NOBLE DRILLING CORP
S-3, 1998-12-08
DRILLING OIL & GAS WELLS
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<PAGE>   1


    AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON DECEMBER 8, 1998
                                                             FILE NO. 333-

================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                ---------------

                                    FORM S-3
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                                ---------------

                           NOBLE DRILLING CORPORATION
             (Exact name of registrant as specified in its charter)


          DELAWARE                                       73-0374541
(State or other jurisdiction of             (I.R.S. employer identification no.)
 incorporation or organization)

<TABLE>
<S>                                                      <C>
              10370 RICHMOND AVENUE                                        JAMES C. DAY
                   SUITE 400                              CHAIRMAN, PRESIDENT AND CHIEF EXECUTIVE OFFICER
              HOUSTON, TEXAS 77042                                  NOBLE DRILLING CORPORATION
                (713) 974-3131                                   10370 RICHMOND AVENUE, SUITE 400
(Address, including zip code, and telephone number,                   HOUSTON, TEXAS 77042
  including area code, of Registrant's principal                         (713) 974-3131
              executive offices)                         (Name, address, including zip code, and telephone
                                                         number, including area code, of agent for service)
</TABLE>

                                ---------------

                                 With a copy to:
                                 David L. Emmons
                             Thompson & Knight, P.C.
                         1700 Pacific Avenue, Suite 3300
                               Dallas, Texas 75201

         APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC: From
time to time after effectiveness

         If the only securities being registered on this form are being offered
pursuant to dividend or interest reinvestment plans, check the following box.[ ]

         If any of the securities being registered on this form are to be
offered on a delayed or continuous basis pursuant to Rule 415 under the
Securities Act of 1933, other than securities offered only in connection with
dividend or interest reinvestment plans, check the following box. [X]

         If this form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list the Securities Act registration statement number of the earlier
effective registration statement for the same offering. [ ]

         If this form is a post-effective amendment filed pursuant to Rule
462(b) under the Securities Act, check the following box and list the Securities
Act registration statement number of the earlier effective registration
statement for the same offering. [ ]

         If delivery of the prospectus is expected to be made pursuant to Rule
434, please check the following box. [ ]

                                ---------------

                       CALCULATION OF REGISTRATION FEE(1)
<TABLE>
<CAPTION>
- -----------------------------------------------------------------------------------------------------------------------------------
                                                  Proposed Maximum    Proposed Maximum
          Title of Each Class of                    Amount to be     Offering Price per    Aggregate Offering         Amount of
        Securities to be Registered                  Registered           Unit(1)              Price(1)          Registration Fee
- -----------------------------------------------------------------------------------------------------------------------------------
<S>                                               <C>                        <C>             <C>                      <C>
Debt Securities(2)(3)...........................
- -----------------------------------------------------------------------------------------------------------------------------------
Common Stock, par value $.10 per share(3).......
- -----------------------------------------------------------------------------------------------------------------------------------
Preferred Stock, par value $1.00 per share(3)(4)
- -----------------------------------------------------------------------------------------------------------------------------------
Depositary Shares(5)............................
- -----------------------------------------------------------------------------------------------------------------------------------
Warrants(6).....................................
- -----------------------------------------------------------------------------------------------------------------------------------
Total...........................................  (1)$300,000,000            100%            (1)$300,000,000          $83,400
- -----------------------------------------------------------------------------------------------------------------------------------
</TABLE>



<PAGE>   2

(1)      Estimated solely for the purpose of calculating the registration fee
         pursuant to Rule 457(o). In no event will the aggregate initial
         offering price of all securities issued from time to time pursuant to
         this Registration Statement exceed $300,000,000. Any securities
         registered hereunder may be sold separately or as units with other
         securities registered hereunder.

(2)      Subject to note (1), there are being registered hereunder an
         indeterminate principal amount of Debt Securities. If any Debt
         Securities are being issued at an original issue discount, then the
         offering price shall be in such greater principal amount as shall
         result in an aggregate initial offering price not to exceed
         $300,000,000, less the dollar amount of any securities previously
         issued hereunder.

(3)      Subject to note (1), there are being registered hereunder an
         indeterminate number of shares of Common Stock as may be sold, from
         time to time, by the Registrant. There are also being registered
         hereunder an indeterminate number of shares of Common Stock as shall be
         issuable upon conversion or redemption of Preferred Stock or Debt
         Securities registered hereby. The Common Stock being registered
         includes associated Preferred Stock purchase rights.

(4)      Subject to note (1), there are being registered hereunder an
         indeterminate number of shares of Preferred Stock as may be sold, from
         time to time, by the Registrant.

(5)      Subject to note (1), there are being registered hereunder an
         indeterminate number of Depositary Shares to be evidenced by Depositary
         Receipts issued pursuant to a Deposit Agreement. In the event the
         Registrant elects to offer to the public fractional interests in shares
         of Preferred Stock registered hereunder, Depositary Receipts will be
         distributed to those persons purchasing such fractional interests, and
         the shares of Preferred Stock will be issued to the depositary under
         the Deposit Agreement.

(6)      Subject to note (1), there are being registered hereunder an
         indeterminate amount and number of Warrants, representing rights to
         purchase Preferred Stock, Common Stock or Debt Securities registered
         hereby or equity securities issued by an unaffiliated corporation or
         other entity and held by the Registrant.

                               ------------------

         The registrant hereby amends this registration statement on such date
or dates as may be necessary to delay its effective date until the registrant
shall file a further amendment which specifically states that this registration
statement shall thereafter become effective in accordance with section 8(a) of
the Securities Act of 1933 or until the registration statement shall become
effective on such date as the SEC, acting pursuant to said section 8(a), may
determine.

================================================================================



<PAGE>   3
                  Subject to Completion Dated December 8, 1998
Preliminary Prospectus




                                  $300,000,000
                                                                          [LOGO]
                                 DEBT SECURITIES
                                  COMMON STOCK
                                 PREFERRED STOCK
                                    WARRANTS


                           NOBLE DRILLING CORPORATION


                              -------------------


         We may offer from time to time (1) unsecured debt securities consisting
of senior notes and debentures and subordinated notes and debentures and/or
other unsecured evidences of indebtedness in one or more series; (2) shares of
common stock; (3) shares of preferred stock, in one or more series, which may be
convertible into or exchangeable for common stock or debt securities; and (4)
warrants to purchase debt securities, preferred stock, common stock or other
securities.

         The aggregate initial offering price of the securities that we offer
will not exceed $300,000,000. We will offer the securities in amounts, at prices
and on terms to be determined by market conditions at the time of our offerings.

         We will provide the specific terms of the securities in supplements to
this Prospectus. You should read this Prospectus and the Prospectus Supplements
carefully before you invest in any of our securities. This Prospectus may not be
used to consummate sales of our securities unless it is accompanied by a
Prospectus Supplement.


                              -------------------


         Neither the Securities and Exchange Commission nor any state securities
commission has approved of the securities to be issued under this Prospectus or
determined if this Prospectus is accurate or adequate. Any representation to the
contrary is a criminal offense.


                              -------------------

         The information in this Prospectus is incomplete and may be changed. We
may not sell these securities until the registration statement filed with the
Securities and Exchange Commission is effective. This Prospectus is not an offer
to sell these securities and it is not soliciting an offer to buy these
securities in any state where the offer or sale is not permitted. We may not use
this Prospectus to sell securities unless we also give prospective investors a
Prospectus Supplement.


                              -------------------


                    This Prospectus is dated December , 1998

<PAGE>   4




                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                                                       PAGE
                                                                                                                       ----
<S>                                                                                                                      <C>
ABOUT THIS PROSPECTUS.....................................................................................................2
WHERE YOU CAN FIND MORE INFORMATION.......................................................................................2
THE COMPANY...............................................................................................................3
RISK FACTORS..............................................................................................................3
         Dependance on the Oil and Gas Industry...........................................................................3
         Risks of Modification, Refurbishment and Upgrade Projects........................................................3
A WARNING ABOUT FORWARD-LOOKING STATEMENTS................................................................................4
USE OF PROCEEDS...........................................................................................................4
RATIO OF EARNINGS TO FIXED CHARGES........................................................................................5
DESCRIPTION OF DEBT SECURITIES............................................................................................5
         General..........................................................................................................5
         Denominations....................................................................................................6
         Subordination....................................................................................................6
         Consolidation, Merger or Sale....................................................................................7
         Modification of Indentures.......................................................................................7
         Events of Default................................................................................................7
         Covenants........................................................................................................8
         Payment and Transfer.............................................................................................8
         Global Securities................................................................................................8
         Defeasance......................................................................................................10
         Meetings........................................................................................................10
         Governing Law...................................................................................................10
         Notices.........................................................................................................11
DESCRIPTION OF CAPITAL STOCK.............................................................................................11
         General.........................................................................................................11
         Common Stock....................................................................................................11
         Preferred Stock and Depositary Shares...........................................................................11
         Warrants........................................................................................................17
         Foreign Ownership...............................................................................................17
         Preferred Stock Purchase Rights.................................................................................17
PLAN OF DISTRIBUTION.....................................................................................................18
         By Agents.......................................................................................................18
         By Underwriters.................................................................................................18
         Direct Sales....................................................................................................18
         General Information.............................................................................................18
LEGAL MATTERS............................................................................................................18
EXPERTS..................................................................................................................18
</TABLE>



<PAGE>   5




                              ABOUT THIS PROSPECTUS

         This Prospectus is part of a registration statement that we filed with
the Securities and Exchange Commission (the "SEC") utilizing a "shelf"
registration process. Under this shelf process, we may, over the next two years,
sell different types of the securities described in this Prospectus in one or
more offerings up to a total offering amount of $300,000,000. This Prospectus
provides you with a general description of the securities we may offer. Each
time we sell securities, we will provide a Prospectus Supplement that will
contain specific information about the terms of that offering and the securities
offered by us in that offering. The Prospectus Supplement may also add, update
or change information contained in this Prospectus. You should read both this
Prospectus and any Prospectus Supplement together with additional information
described under the heading WHERE YOU CAN FIND MORE INFORMATION.


                       WHERE YOU CAN FIND MORE INFORMATION

         We file annual, quarterly and special reports, proxy statements and
other information with the SEC. Our SEC filings are available to the public over
the Internet at the SEC's web site at http://www.sec.gov. You may also read and
copy any document we file at the SEC's public reference rooms in Washington,
D.C., New York, New York and Chicago, Illinois. Please call the SEC at
1-800-SEC-0330 for further information on the public reference rooms.

         The SEC allows us to "incorporate by reference" the information we file
with them, which means that we can disclose important information to you by
referring you to those documents. The information incorporated by reference is
an important part of this Prospectus, and information that we file later with
the SEC will automatically update and supersede this information. We incorporate
by reference the documents listed below and any future filings we make with the
SEC under Sections 13(a), 13(c), 14, or 15(d) of the Securities Exchange Act of
1934 until our offering is completed.

         o        Annual Report on Form 10-K for the year ended December 31,
                  1997;

         o        Quarterly Reports on Form 10-Q for the quarters ended March
                  31, 1998, June 30, 1998 and September 30, 1998; and

         o        The descriptions of our Common Stock and Preferred Stock
                  Purchase Rights contained in our Registration Statements filed
                  under Section 12 of the Securities Exchange Act of 1934.

         You may request a copy of these filings, at no cost, by writing or
telephoning us at the following address:

                  Julie J. Robertson
                  Vice President-Administration and Corporate Secretary
                  Noble Drilling Corporation
                  10370 Richmond Avenue, Suite 400
                  Houston, Texas 77042
                  (713) 974-3131

         You should rely only on the information incorporated by reference or
provided in this Prospectus or any Prospectus Supplement. We have not authorized
anyone else to provide you with different information. We are not making an
offer of these securities in any state where the offer is not permitted. You
should not assume that the information in this Prospectus or any Prospectus
Supplement is accurate as of any date other than the date on the front of those
documents.

                                        2

<PAGE>   6




                                   THE COMPANY

         Noble Drilling Corporation provides diversified services to the oil and
gas industry worldwide, including offshore drilling services, turnkey drilling
services and engineering and production management services. Because our
drilling fleet is broadly diversified, we are able to provide drilling services
in a variety of water depths and operating conditions. We have been providing
contract oil and gas drilling services in the United States since 1921 and
internationally during various periods since 1939.

         Our offshore drilling rig fleet consists of 47 units comprising nine
semisubmersibles (including one active, five submersibles in various stages of
conversion, one semisubmersible being upgraded and two hulls), three dynamically
positioned drillships, 32 independent leg cantilevered jackup rigs (one of which
is bareboat chartered by a 50% owned subsidiary) and three submersibles. These
rig counts include two units in which the Company has a partial ownership
interest: one semisubmersible hull - 50% interest (with an option to increase to
70%) and one drillship - 41% interest.

         Under our EVA-4000(TM) program, we have been converting submersible
units to semisubmersible units. We expect to complete one such conversion, the
Noble Paul Romano, by the end of 1998 and we expect to complete and deliver a
second conversion, the Noble Paul Wolff, in the first quarter of 1999. We have
already begun three other EVA-4000(TM) conversions which we expect to deliver in
1999. In addition, we are substantially upgrading one of our semisubmersibles.
These conversion projects are part of our strategy to increase the number of
rigs in our fleet capable of drilling in deeper water.


                                  RISK FACTORS

         Investing in our securities involves a certain amount of risk. You
should carefully consider the following factors, among others, before deciding
to invest.

DEPENDENCE ON THE OIL AND GAS INDUSTRY

         We depend on the levels of activity in offshore world oil and U.S.
natural gas exploration, development and production. Both short-term and
long-term trends in oil and natural gas prices affect that activity. In recent
years, crude oil and natural gas production, and the availability of drilling
rigs, have been extremely volatile. The domestic price of U.S. benchmark crude
oil recently approached a four-year low. Weakness and uncertainty in the demand
for and price of natural gas in the Gulf of Mexico, from time to time,
contributes to decreased exploration and production activities. Demand for
drilling services outside the United States, excluding the North Sea, has been
less volatile in recent years, but still depends on a variety of political and
economic factors beyond our control, including worldwide demand for oil and
natural gas, the ability of the Organization of Petroleum Exporting Countries
("OPEC") to set and maintain production levels and pricing, the level of
production of non-OPEC countries and the policies of the various governments
regarding exploration and development of their oil and natural gas reserves.

         If the domestic price of natural gas decreases, our dayrates on new
contracts and utilization rates in the U.S. Gulf will likely decrease.
Similarly, if the prices of crude oil or natural gas decrease in other world
markets where our international drilling units compete, our rates in those
markets will decrease. We cannot predict the future level of demand for our
drilling services, and we cannot predict the future conditions in the offshore
contract drilling industry.

RISKS OF MODIFICATION, REFURBISHMENT AND UPGRADE PROJECTS

         We intend to commit a significant amount of our capital resources to
modify, refurbish and upgrade certain of our drilling rigs. We are upgrading
five of our shallow water submersible rigs into EVA-4000(TM) design
semisubmersible rigs. In addition, we are substantially upgrading one of our
semisubmersibles. These projects are subject to the risks of delay or cost
overruns inherent in large construction and refurbishment projects, including
shipyard availability, shortages of materials or skilled labor, unforeseen
engineering problems, work stoppages,

                                        3

<PAGE>   7




weather interference, unanticipated cost increases, nonavailability of necessary
equipment and inability to obtain any of the requisite permits or approvals.
Significant delays will hurt our marketing plans for such rigs and may
jeopardize the contracts or letters of intent we have negotiated for such rigs.


                   A WARNING ABOUT FORWARD-LOOKING STATEMENTS

         We make forward-looking statements in this document, and in our public
documents to which we refer, that are subject to risks and uncertainties in
addition to those set forth above. These forward-looking statements include
information about possible or assumed future results of our operations. Also,
when we use any of the words "believes," "expects," "anticipates" or similar
expressions, we are making forward-looking statements. Many possible events or
factors could affect our future financial results and performance. This could
cause our results or performance to differ materially from those we express in
our forward-looking statements. You should consider these risks when you
purchase securities. These possible events or factors include the following:

         o        volatility in crude oil and natural gas prices;

         o        heavy demand for the equipment and services that we need in
                  order to finish on schedule the major shipyard refurbishment
                  and conversion projects that are in various stages of
                  completion or that we plan to begin;

         o        potential further deterioration of our customer's demand for
                  our drilling services in the U.S. Gulf of Mexico, where a
                  number of our drilling rigs are located;

         o        risks associated with turnkey drilling operations;

         o        intense competition in the drilling industry;

         o        political and economic conditions in international markets
                  where we operate;

         o        adverse weather (such as hurricanes) and seas;

         o        operational risks (such as blowouts, fires and loss of
                  production);

         o        early termination provisions generally found in our drilling
                  contracts;

         o        limitations on insurance coverage; and

         o        requirements and potential liability imposed by governmental
                  regulation of the drilling industry (including environmental
                  regulation).


                                 USE OF PROCEEDS

         Unless we specify otherwise in the applicable Prospectus Supplement,
the net proceeds (after the payment of offering expenses and underwriting
discounts or commissions) we receive from the sale of the securities offered by
this Prospectus and any Prospectus Supplement will be used for general corporate
purposes. General corporate purposes may include any of the following:

         o        repaying debt;

         o        investing in or lending money to our subsidiaries;

         o        providing working capital;


                                        4

<PAGE>   8




         o        funding capital expenditures;

         o        redeeming our preferred stock (currently, there is none
                  outstanding); or

         o        paying for possible acquisitions or the expansion of our
                  businesses.

We may temporarily invest the net proceeds we receive from any offering of
securities or use the net proceeds to repay short-term debt until we can use
them for their stated purposes.


                       RATIO OF EARNINGS TO FIXED CHARGES

         The ratio of earnings to fixed charges for each of the periods
indicated is as follows:

<TABLE>
<CAPTION>
- -------------------------------------------------------------------------------------------------------------------------
       Nine Months                                       Twelve Months Ended December 31,
          Ended            ----------------------------------------------------------------------------------------------
   September 30, 1998           1997                1996                1995               1994                1993
- -------------------------------------------------------------------------------------------------------------------------
<S>       <C>                   <C>                  <C>                 <C>                <C>                 <C>
          12.1                  20.6                 6.0                 1.4                3.1                 4.1
- -------------------------------------------------------------------------------------------------------------------------
</TABLE>

         These computations include us and our subsidiaries, and companies in
which we own 50% or less of the outstanding equity. For these ratios, "earnings"
is determined by adding "total fixed charges" (excluding interest capitalized),
income taxes, minority common stockholders equity in net income and amortization
of interest capitalized to income from continuing operations after eliminating
equity in undistributed earnings and adding back losses of companies in which at
least 20% but less than 50% equity is owned. For this purpose, "total fixed
charges" consists of (1) interest on all indebtedness and amortization of debt
discount and expense, (2) interest capitalized and (3) an interest factor
attributable to rentals.


                         DESCRIPTION OF DEBT SECURITIES

         Any Debt Securities we offer will be our direct unsecured general
obligations. The Debt Securities will be either senior debt securities or
subordinated debt securities. The Debt Securities will be issued under one or
more separate indentures between us and Chase Bank of Texas, National
Association, as Trustee. Senior Debt Securities will be issued under a "Senior
Indenture" and Subordinated Debt Securities will be issued under a "Subordinated
Indenture". Together the Senior Indenture and the Subordinated Indenture are
called "Indentures".

         We have summarized selected provisions of the Indentures below. The
summary is not complete. The forms of the Indentures have been filed as exhibits
to the registration statement and you should read the Indentures for provisions
that may be important to you. In the summary below, we have included references
to section numbers of the applicable Indentures so that you can easily locate
these provisions. Capitalized terms used in the summary have the meanings
specified in the Indentures.

GENERAL

         The Debt Securities will be our direct, unsecured obligations. The
Senior Debt Securities will rank equally with all of our other senior and
unsubordinated debt. The Subordinated Debt Securities will have a junior
position to all of our Senior Debt.

         We conduct a substantial part of our operations through our
subsidiaries. To the extent of such operations, holders of Debt Securities will
have a position junior to the prior claims of creditors of our subsidiaries,
including trade creditors, debtholders, secured creditors, taxing authorities
and guarantee holders, and any preferred stockholders, except to the extent that
we may ourself be a creditor with recognized claims against any subsidiary.

                                        5

<PAGE>   9




Our ability to pay principal of and premium, if any, and interest on any Debt
Securities is, to a large extent, dependent upon the payment to us of dividends,
interest or other charges by our subsidiaries.

         One of our subsidiaries recently borrowed $145 million, and another
subsidiary has entered into a note purchase agreement pursuant to which it will
borrow an additional $112.25 million, in connection with the Noble Paul Romano
and Noble Paul Wolff conversions from submersibles to EVA-4000(TM)
semisubmersibles. In addition, a third subsidiary is currently seeking to obtain
financing in the amount of $115 million in connection with the similar
conversion of the Noble Jim Thompson. The outstanding indebtedness for the Noble
Paul Wolff is, and for the Noble Jim Thompson will be, guaranteed by us. The
outstanding indebtedness for the Noble Paul Romano is non-recourse to us and any
of our subsidiaries other than the subsidiary that issued the debt.

         A Prospectus Supplement and a supplemental indenture relating to any
series of Debt Securities being offered will include specific terms relating to
the offering. These terms will include some or all of the following:

         o        The title and type of the Debt Securities;

         o        The total principal amount of the Debt Securities;

         o        The percentage of the principal amount at which the Debt
                  Securities will be issued and any payments due if the maturity
                  of the Debt Securities is accelerated;

         o        The dates on which the principal of the Debt Securities will
                  be payable;

         o        The interest rate which the Debt Securities will bear and the
                  interest payment dates for the Debt Securities;

         o        Any optional redemption periods;

         o        Any sinking fund or other provisions that would obligate us to
                  repurchase or otherwise redeem some or all of the Debt
                  Securities;

         o        Any provisions granting special rights to holders when a
                  specified event occurs;

         o        Any changes to or additional Events of Defaults or covenants;

         o        Any special tax implications of the Debt Securities, including
                  provisions for Original Issue Discount Securities, if offered;
                  and

         o        Any other terms of the Debt Securities.

         None of the Indentures limits the amount of Debt Securities that may be
issued. Each Indenture allows Debt Securities to be issued up to the principal
amount that may be authorized by us and may be in any currency or currency unit
designated by us.

         Debt Securities of a series may be issued in registered, bearer, coupon
or global form. (Sections 201 & 203.)

DENOMINATIONS

         The Prospectus Supplement for each issuance of Debt Securities will
state whether the securities will be issued in registered form of $1,000 each or
multiples thereof or bearer form of $5,000 each.





                                        6

<PAGE>   10




SUBORDINATION

         Under the Subordinated Indenture, payment of the principal, interest
and any premium on the Subordinated Debt Securities will generally be
subordinated and junior in right of payment to the prior payment in full of all
Senior Debt. The Subordinated Indenture provides that no payment of principal,
interest and any premium on the Subordinated Debt Securities may be made in the
event:

         o        of any insolvency, bankruptcy or similar proceeding involving
                  us or our property, or

         o        we fail to pay the principal, interest, any premium or any
                  other amounts on any Senior Debt when due.

         The Subordinated Indenture will not limit the amount of Senior Debt
that we may incur.

         "Senior Debt" is defined to include all notes or other unsecured
evidences of indebtedness, including guarantees given by us, for money borrowed
by us, not expressed to be subordinate or junior in right of payment to any of
our other indebtedness.

CONSOLIDATION, MERGER OR SALE

         Each Indenture generally permits a consolidation or merger between us
and another corporation. They also permit the sale by us of all or substantially
all of our property and assets. If this happens, the remaining or acquiring
corporation shall assume all of our responsibilities and liabilities under the
Indentures, including the payment of all amounts due on the Debt Securities and
performance of the covenants in the Indentures. However, we will consolidate or
merge with or into any other corporation or sell all or substantially all of our
assets only according to the terms and conditions of the Indentures. The
remaining or acquiring corporation will be substituted for us in the Indentures
with the same effect as if it had been an original party to the Indentures.
Thereafter, the successor corporation may exercise our rights and powers under
any Indenture, in our name or in its own name. Any act or proceeding required or
permitted to be done by our Board of Directors or any of our officers may be
done by the board or officers of the successor corporation. If we sell all or
substantially all of our assets, we shall be released from all our liabilities
and obligations under any Indenture and under the Debt Securities. (Sections 801
& 802.)

MODIFICATION OF INDENTURES

         Under each Indenture our rights and obligations and the rights of the
holders may be modified with the consent of the holders of a majority in
aggregate principal amount of the outstanding Debt Securities of each series
affected by the modification. No modification of the principal or interest
payment terms, and no modification reducing the percentage required for
modifications, is effective against any holder without its consent. (Sections
901 & 902.)

EVENTS OF DEFAULT

         "Event of Default" when used in an Indenture, will mean any of the
following:

         o        failure to pay the principal of or any premium on any Debt
                  Security when due;

         o        failure to deposit any sinking fund payment when due;

         o        failure to pay interest on any Debt Security for 30 days;

         o        failure to perform any other covenant in the Indenture that
                  continues for 90 days after being given written notice;

         o        certain events in bankruptcy, insolvency or reorganization of
                  Noble Drilling Corporation; or


                                        7

<PAGE>   11




         o        any other Event of Default included in any Indenture or
                  supplemental indenture. (Section 501.)

         An Event of Default for a particular series of Debt Securities does not
necessarily constitute an Event of Default for any other series of Debt
Securities issued under an Indenture. The Trustee may withhold notice to the
holders of Debt Securities of any default (except in the payment of principal or
interest) if it considers such withholding of notice to be in the best interests
of the holders. (Section 602.)

         If an Event of Default for any series of Debt Securities occurs and
continues, the Trustee or the holders of at least 25% in aggregate principal
amount of the Debt Securities of the series may declare the entire principal of
all the Debt Securities of that series to be due and payable immediately. If
this happens, subject to certain conditions, the holders of a majority of the
aggregate principal amount of the Debt Securities of that series can void the
declaration. (Section 502.)

         Other than its duties in case of a default, a Trustee is not obligated
to exercise any of its rights or powers under any Indenture at the request,
order or direction of any holders, unless the holders offer the Trustee
reasonable indemnity. (Section 601.) If they provide this reasonable
indemnification, the holders of a majority in principal amount of any series of
Debt Securities may direct the time, method and place of conducting any
proceeding or any remedy available to the Trustee, or exercising any power
conferred upon the Trustee, for any series of Debt Securities. (Section 512.)

COVENANTS

         Under the Indentures, we will:

         o        pay the principal of, and interest and any premium on, the
                  Debt Securities when due;

         o        maintain a place of payment;

         o        deliver a report to the Trustee at the end of each fiscal year
                  reviewing our obligations under the Indentures; and

         o        deposit sufficient funds with any paying agent on or before
                  the due date for any principal, interest or premium.

PAYMENT AND TRANSFER

         Principal, interest and any premium on fully registered securities will
be paid at designated places. Payment will be made by check mailed to the
persons in whose names the Debt Securities are registered on days specified in
the Indentures or any Prospectus Supplement. Debt Securities payments in other
forms will be paid at a place designated by us and specified in a Prospectus
Supplement. (Section 307.)

         Fully registered securities may be transferred or exchanged at the
corporate trust office of the Trustee or at any other office or agency
maintained by us for such purposes, without the payment of any service charge
except for any tax or governmental charge. (Section 1002.)

GLOBAL SECURITIES

         Certain series of the Debt Securities may be issued as permanent global
Debt Securities to be deposited with a depositary with respect to that series.
Unless otherwise indicated in the Prospectus Supplement, the following is a
summary of the depository arrangements applicable to Debt Securities issued in
permanent global form and for which The Depositary Trust Company ("DTC") acts as
depositary (the "Global Debt Securities").

         Each Global Debt Security will be deposited with, or on behalf of, DTC,
as depositary, or its nominee and registered in the name of a nominee of DTC.
Except under the limited circumstances described below, Global Debt Securities
are not exchangeable for definitive certificated Debt Securities.

                                        8

<PAGE>   12




         Ownership of beneficial interests in a Global Debt Security is limited
to institutions that have accounts with DTC or its nominee ("participants") or
persons that may hold interests through participants. In addition, ownership of
beneficial interests by participants in a Global Debt Security will be evidenced
only by, and the transfer of that ownership interest will be effected only
through, records maintained by DTC or its nominee for a Global Debt Security.
Ownership of beneficial interests in a Global Debt Security by persons that hold
through participants will be evidenced only by, and the transfer of that
ownership interest within that participant will be effected only through,
records maintained by that participant. DTC has no knowledge of the actual
beneficial owners of the Debt Securities. Beneficial owners will not receive
written confirmation from DTC of their purchase, but beneficial owners are
expected to receive written confirmations providing details of the transaction,
as well as periodic statements of their holdings, from the participants through
which the beneficial owners entered the transaction. The laws of some
jurisdictions require that certain purchasers of securities take physical
delivery of such securities in definitive form. Such laws may impair the ability
to transfer beneficial interests in a Global Debt Security.

         Payment of principal of, and interest on, Debt Securities represented
by a Global Debt Security registered in the name of or held by DTC or its
nominee will be made to DTC or its nominee, as the case may be, as the
registered owner and holder of the Global Debt Security representing those Debt
Securities. We have been advised by DTC that upon receipt of any payment of
principal of, or interest on, a Global Debt Security, DTC will immediately
credit accounts of participants on its book-entry registration and transfer
system with payments in amounts proportionate to their respective beneficial
interests in the principal amount of that Global Debt Security as shown in the
records of DTC. Payments by participants to owners of beneficial interests in a
Global Debt Security held through those participants will be governed by
standing instructions and customary practices, as is now the case with
securities held for the accounts of customers in bearer form or registered in
"street name", and will be the sole responsibility of those participants,
subject to any statutory or regulatory requirements that may be in effect from
time to time.

         Neither we, any Trustee nor any of our respective agents will be
responsible for any aspect of the records of DTC, any nominee or any participant
relating to, or payments made on account of, beneficial interests in a permanent
Global Debt Security or for maintaining, supervising or reviewing any of the
records of DTC, any nominee or any participant relating to such beneficial
interests.

         A Global Debt Security is exchangeable for definitive Debt Securities
registered in the name of, and a transfer of a Global Debt Security may be
registered to, any person other than DTC or its nominee, only if:

         o        DTC notifies us that it is unwilling or unable to continue as
                  depositary for that Global Debt Security or at any time DTC
                  ceases to be registered under the Exchange Act;

         o        we determine in our discretion that the Global Debt Security
                  shall be exchangeable for definitive Debt Securities in
                  registered form; or

         o        there shall have occurred and be continuing an Event of
                  Default or an event which, with notice or the lapse of time or
                  both, would constitute an Event of Default under the Debt
                  Securities.

         Any Global Debt Security that is exchangeable pursuant to the preceding
sentence will be exchangeable in whole for definitive Debt Securities in
registered form, of like tenor and of an equal aggregate principal amount as the
Global Debt Security, in denominations specified in the applicable Prospectus
Supplement (if other than $1,000 and integral multiples of $1,000). The
definitive Debt Securities will be registered by the registrar in the name or
names instructed by DTC. We expect that these instructions may be based upon
directions received by DTC from its participants with respect to ownership of
beneficial interests in the Global Debt Security.

         Except as provided above, owners of the beneficial interests in a
Global Debt Security will not be entitled to receive physical delivery of Debt
Securities in definitive form and will not be considered the holders of Debt
Securities for any purpose under the Indentures. No Global Debt Security shall
be exchangeable except for another Global Debt Security of like denomination and
tenor to be registered in the name of DTC or its nominee. Accordingly, each
person owning a beneficial interest in a Global Debt Security must rely on the
procedures of

                                        9

<PAGE>   13




DTC and, if that person is not a participant, on the procedures of the
participant through which that person owns its interest, to exercise any rights
of a holder under the Global Debt Security or the Indentures.

         We understand that, under existing industry practices, in the event
that we request any action of holders, or an owner of a beneficial interest in a
Global Debt Security desires to give or take any action that a holder is
entitled to give or take under the Debt Securities or the Indentures, DTC would
authorize the participants holding the relevant beneficial interests to give or
take that action, and those participants would authorize beneficial owners
owning through those participants to give or take that action or would otherwise
act upon the instructions of beneficial owners owning through them.

         DTC has advised us that DTC is a limited purpose trust company
organized under the laws of the State of New York, a "banking organization"
within the meaning of the New York Banking Law, a member of the Federal Reserve
System, a "clearing corporation" within the meaning of the New York Uniform
Commercial Code and a "clearing agency" registered under the Exchange Act. DTC
was created to hold securities of its participants and to facilitate the
clearance and settlement of securities transactions among its participants in
those securities through electronic book-entry changes in accounts of the
participants, thereby eliminating the need for physical movement of securities
certificates. DTC's participants include securities brokers and dealers, banks,
trust companies, clearing corporations and certain other organizations. DTC is
owned by a number of its participants and by the New York Stock Exchange, Inc.,
the American Stock Exchange, Inc. and the National Association of Securities
Dealers, Inc. Access to DTC's book-entry system is also available to others,
such as banks, brokers, dealers and trust companies that clear through or
maintain a custodial relationship with a participant, either directly or
indirectly. The rules applicable to DTC and its participants are on file with
the SEC.

DEFEASANCE

         We will be discharged from our obligations on the Debt Securities of
any series at any time if we deposit with the Trustee sufficient cash or
government securities to pay the principal, interest, any premium and any other
sums due to the stated maturity date or a redemption date of the Debt Securities
of the series. If this happens, the holders of the Debt Securities of the series
will not be entitled to the benefits of the Indenture except for registration of
transfer and exchange of Debt Securities and replacement of lost, stolen or
mutilated Debt Securities. (Section 401.)

         Under Federal income tax law as of the date of this Prospectus, a
discharge may be treated as an exchange of the related Debt Securities. Each
holder might be required to recognize gain or loss equal to the difference
between the holder's cost or other tax basis for the Debt Securities and the
value of the holder's interest in the trust. Holders might be required to
include as income a different amount than would be includable without the
discharge. Prospective investors are urged to consult their own tax advisers as
to the consequences of a discharge, including the applicability and effect of
tax laws other than the Federal income tax law.

 MEETINGS

         Each Indenture contains provisions describing how meetings of the
Holders of Debt Securities of a series may be convened. A meeting may be called
at any time by the Trustee, and also, upon request, by us or the Holders of at
least 10% in principal amount of the outstanding Debt Securities of a series. A
notice of the meeting must always be given in the manner described under
"-Notices" below. Generally speaking, except for any consent that must be given
by all Holders of a series as described under "-Modification of Indentures"
above, any resolution presented at a meeting of the Holders of a series of Debt
Securities may be adopted by the affirmative vote of the Holders of a majority
in principal amount of the outstanding Debt Securities of that series, unless
the Indenture allows the action to be voted upon to be taken with the approval
of the Holders of a different specific percentage of principal amount of
outstanding Debt Securities of a series. In that case, the Holders of
outstanding Debt Securities of at least the specified percentage must vote in
favor of the action. Any resolution passed or decision taken at any meeting of
Holders of Debt Securities of any series in accordance with the applicable
Indenture will be binding on all Holders of Debt Securities of that series and
any related coupons, unless, as discussed in "-Modification of Indentures"
above, the action is only effective against Holders that have approved it. The
quorum at any meeting

                                       10

<PAGE>   14




called to adopt a resolution, and at any reconvened meeting, will be Holders
holding or representing a majority in principal amount of the outstanding Debt
Securities of a series.

GOVERNING LAW

         Each Indenture and the Debt Securities will be governed by and
construed in accordance with the laws of the State of New York.

NOTICES

         Notices to Holders of Debt Securities will be given by mail to the
addresses of such Holders as they appear in the Security Register.


                          DESCRIPTION OF CAPITAL STOCK

GENERAL

         As of the date of this Prospectus, we are authorized to issue up to
215,000,000 shares of stock, including up to 200,000,000 shares of Common Stock
and up to 15,000,000 shares of Preferred Stock. As of November 6, 1998, we had
131,077,729 shares of Common Stock and no shares of Preferred Stock outstanding.
As of that date, we also had approximately 3,287,381 shares of Common Stock
reserved for issuance upon exercise of options or in connection with other
awards outstanding under various employee or director incentive, compensation
and option plans. In addition, we have reserved for issuance shares of Common
Stock for our matching fund obligations under our 401(k) savings plan and
employee retirement plans.

         The following summary is not complete. You should refer to the
applicable provisions of our Certificate of Incorporation, the Delaware General
Corporation Law and the documents we have incorporated by reference for a
complete statement of the terms and rights of our capital stock.

COMMON STOCK

         Voting Rights. Each Holder of Common Stock is entitled to one vote per
share. Subject to the rights, if any, of the holders of any series of Preferred
Stock pursuant to applicable law or the provision of the Certificate of
Designations creating that series, all voting rights are vested in the holders
of shares of Common Stock. Holders of shares of Common Stock have noncumulative
voting rights, which means that the holders of more than 50% of the shares
voting for the election of directors can elect 100% of the directors, and the
holders of the remaining shares voting for the election of directors will not be
able to elect any directors.

         Dividends. Dividends may be paid to the holders of Common Stock when,
as and if declared by the Board of Directors out of funds legally available for
their payment, subject to the rights of holders of any Preferred Stock.

         Rights Upon Liquidation. In the event of our voluntary or involuntary
liquidation, dissolution or winding up, the holders of Common Stock will be
entitled to share equally in any of our assets available for distribution after
the payment in full of all debts and distributions and after the holders of all
series of outstanding Preferred Stock, if any, have received their liquidation
preferences in full.

         Miscellaneous. The issued and outstanding shares of Common Stock are
fully paid and nonassessable. Holders of shares of Common Stock are not entitled
to preemptive rights. Shares of Common Stock are not convertible into shares of
any other class of capital stock. Bank One Trust Company, N.A., Oklahoma City,
Oklahoma, is the transfer agent and registrar for the Common Stock. The Common
Stock is listed on the New York Stock Exchange under the symbol "NE."




                                       11

<PAGE>   15




PREFERRED STOCK AND DEPOSITARY SHARES

         We may issue shares of our Preferred Stock in one or more series. We
will determine the dividend, voting, conversion and other rights of the series
being offered and the terms and conditions relating to its offering and sale at
the time of the offer and sale. We may also issue fractional shares of Preferred
Stock that will be represented by Depositary Shares and Depositary Receipts.

         Description of Preferred Stock.

         The Certificate of Incorporation authorizes the Board of Directors or a
committee of the Board of Directors to cause Preferred Stock to be issued in one
or more series, without stockholder action. The Board of Directors is authorized
to issue up to 15,000,000 shares of Preferred Stock, and can determine the
number of shares of each series, and the rights, preferences and limitations of
each series. We may amend the Certificate of Incorporation to increase the
number of authorized shares of Preferred Stock in a manner permitted by the
Certificate of Incorporation and the Delaware General Corporation Law. As of the
date of this Prospectus, we have no shares of Preferred Stock outstanding.

         The particular terms of any series of Preferred Stock being offered by
us under this shelf registration will be described in the Prospectus Supplement
relating to that series of Preferred Stock. Those terms may include:

         o        the number of shares of the series of Preferred Stock being
                  offered;
         
         o        the title and liquidation preference per share of that series
                  of the Preferred Stock;

         o        the purchase price of the Preferred Stock;

         o        the dividend rate (or method for determining such rate);

         o        the dates on which dividends will be paid;

         o        whether dividends on that series of Preferred Stock will be
                  cumulative or non-cumulative and, if cumulative, the dates
                  from which dividends shall commence to accumulate;

         o        any redemption or sinking fund provisions applicable to that
                  series of Preferred Stock;

         o        any conversion provisions applicable to that series of
                  Preferred Stock;

         o        whether we have elected to offer Depositary Shares with
                  respect to that series of Preferred Stock; or

         o        any additional dividend, liquidation, redemption, sinking fund
                  and other rights and restrictions applicable to that series of
                  Preferred Stock.

         If the terms of any series of Preferred Stock being offered differ from
the terms set forth below, those terms will also be disclosed in the Prospectus
Supplement relating to that series of Preferred Stock. The following summary is
not complete. You should refer to the Certificate of Designations relating to
the series of the Preferred Stock for the complete terms of that Preferred
Stock. That Certificate of Designations for any series of Preferred Stock will
be filed with the SEC promptly after the offering of that series of Preferred
Stock.

         The Preferred Stock will, when issued, be fully paid and nonassessable.
Unless otherwise specified in the Prospectus Supplement, in the event we
liquidate, dissolve or wind-up our business, each series of Preferred Stock will
have the same rank as to dividends and distributions as each other series of the
Preferred Stock we may issue in the future. The Preferred Stock will have no
preemptive rights.

         Dividend Rights. Holders of Preferred Stock of each series will be
entitled to receive, when, as and if declared by the Board of Directors, cash
dividends at the rates and on the dates set forth in the Prospectus Supplement.
Dividend rates may be fixed or variable or both. Different series of Preferred
Stock may be entitled to dividends at different dividend rates or based upon
different methods of determination. Each dividend will be payable to the holders
of record as they appear on our stock books (or, if applicable, the records of
the Depositary referred to below under "Depositary Shares") on record dates
determined by the Board of Directors. Dividends on any series of the Preferred
Stock may be cumulative or non-cumulative, as specified in the Prospectus
Supplement. If the Board of Directors fails to declare a dividend on any series
of Preferred Stock for which dividends are non-cumulative, then the right to
receive that dividend will be lost, and we will have no obligation to pay the
dividend for that dividend period, whether or not dividends are declared for any
future dividend period.

                                       12

<PAGE>   16




         No full dividends will be declared or paid on any series of Preferred
Stock, unless full dividends for the dividend period commencing after the
immediately preceding dividend payment date (and cumulative dividends still
owing, if any) have been or contemporaneously are declared and paid on all other
series of Preferred Stock which have the same rank as, or rank senior to, that
series of Preferred Stock. When those dividends are not paid in full, dividends
will be declared pro rata, so that the amount of dividends declared per share on
that series of Preferred Stock and on each other series of Preferred Stock
having the same rank as, or ranking senior to, that series of Preferred Stock
will in all cases bear to each other the same ratio that accrued dividends per
share on that series of Preferred Stock and the other Preferred Stock bear to
each other. In addition, generally, unless full dividends, including cumulative
dividends still owing, if any, on all outstanding shares of any series of
Preferred Stock have been paid, no dividends will be declared or paid on the
Common Stock and generally we may not redeem or purchase any Common Stock. No
interest, or sum of money in lieu of interest, will be paid in connection with
any dividend payment or payments which may be in arrears.

         The amount of dividends payable for each dividend period will be
computed by annualizing the applicable dividend rate and dividing by the number
of dividend periods in a year, except that the amount of dividends payable for
the initial dividend period or any period shorter than a full dividend period
shall be computed on the basis of a 360-day year consisting of twelve 30-day
months and, for any period less than a full month, the actual number of days
elapsed in the period.

         Rights Upon Liquidation. In the event we liquidate, dissolve or wind-up
our affairs, either voluntarily or involuntarily, the holders of each series of
Preferred Stock will be entitled to receive liquidating distributions in the
amount set forth in the Prospectus Supplement relating to each series of
Preferred Stock, plus an amount equal to accrued and unpaid dividends, if any,
before any distribution of assets is made to the holders of Common Stock. If the
amounts payable with respect to Preferred Stock of any series and any stock
having the same rank as that series of Preferred Stock are not paid in full, the
holders of Preferred Stock and of such other stock will share ratably in any
such distribution of assets in proportion to the full respective preferential
amounts to which they are entitled. After the holders of each series of
Preferred Stock and any stock having the same rank as the Preferred Stock are
paid in full, they will have no right or claim to any of our remaining assets.
Neither the sale of all or substantially all our property or business nor a
merger or consolidation by us with any other corporation will be considered a
dissolution, liquidation or winding up by us of our business or affairs.

         Redemption. Any series of Preferred Stock may be redeemable, in whole
or in part, at our option. In addition, any series of Preferred Stock may be
subject to mandatory redemption pursuant to a sinking fund. The redemption
provisions that may apply to a series of Preferred Stock, including the
redemption dates and the redemption prices for that series, will be set forth in
the Prospectus Supplement.

         If a series of Preferred Stock is subject to mandatory redemption, the
Prospectus Supplement will specify the year we can begin to redeem shares of the
Preferred Stock, the number of shares of the Preferred Stock we can redeem each
year, and the redemption price per share. We may pay the redemption price in
cash, stock or in cash that we have received specifically from the sale of our
capital stock, as specified in the Prospectus Supplement. If the redemption
price is to be paid only from the proceeds of the sale of our capital stock, the
terms of the series of Preferred Stock may also provide that, if no such capital
stock is sold or if the amount of cash received is insufficient to pay in full
the redemption price then due, the series of Preferred Stock will automatically
be converted into shares of the applicable capital stock pursuant to conversion
provisions specified in the Prospectus Supplement.

         If fewer than all the outstanding shares of any series of Preferred
Stock are to be redeemed, whether by mandatory or optional redemption, the Board
of Directors will determine the method for selecting the shares to be redeemed,
which may be by lot or pro rata or by any other method determined to be
equitable. From and after the redemption date, dividends will cease to accrue on
the shares of Preferred Stock called for redemption and all rights of the
holders of those shares (except the right to receive the redemption price) will
cease.

         In the event that full dividends, including accrued but unpaid
dividends, if any, have not been paid on any series of Preferred Stock, we may
not redeem that series in part and we may not purchase or acquire any shares of

                                       13

<PAGE>   17




that series of Preferred Stock, except by an offer made on the same terms to all
holders of that series of Preferred Stock.

         Conversion Rights. The Prospectus Supplement will state the terms, if
any, on which shares of a series of Preferred Stock are convertible into shares
of Common Stock or another series of our Preferred Stock. As described under
"-Redemption" above, under certain circumstances, Preferred Stock may be
mandatorily converted into Common Stock or another series of our Preferred
Stock.

         Voting Rights. Except as indicated below or in the Prospectus
Supplement, or except as expressly required by applicable law, the holders of
Preferred Stock will not be entitled to vote. Except as indicated in the
Prospectus Supplement, in the event we issue full shares of any series of
Preferred Stock, each share will be entitled to one vote on matters on which
holders of that series of Preferred Stock are entitled to vote. However, as more
fully described below under "-Description of Depositary Shares", if we issue
Depositary Shares representing a fraction of a share of a series of Preferred
Stock, each Depositary Share will, in effect, be entitled to that fraction of a
vote, rather than a full vote. Because each full share of any series of
Preferred Stock will be entitled to one vote, the voting power of that series
will depend on the number of shares in that series, and not on the aggregate
liquidation preference or initial offering price of the shares of that series of
Preferred Stock.

         Transfer Agent and Registrar. Bank One Trust Company, N.A., Oklahoma
City, Oklahoma will be the transfer agent, registrar and dividend disbursement
agent for the Preferred Stock and any Depositary Shares (see the description of
Depositary Shares below). The registrar for the Preferred Stock will send
notices to the holders of the Preferred Stock of any meetings at which such
holders will have the right to elect directors or to vote on any other matter.

         Description of Depositary Shares.

         General. We may, at our option, elect to offer fractional shares of
Preferred Stock, rather than full shares of Preferred Stock. If we do, we will
issue to the public receipts for Depositary Shares, and each of these Depositary
Shares will represent a fraction (to be set forth in the Prospectus Supplement)
of a share of a particular series of Preferred Stock.

         The shares of any series of Preferred Stock underlying the Depositary
Shares will be deposited under a Deposit Agreement (the "Deposit Agreement")
between us and a bank or trust company selected by us (the "Depositary").
Subject to the terms of the Deposit Agreement, each owner of a Depositary Share
will be entitled, in proportion to the applicable fractional interest in shares
of Preferred Stock underlying that Depositary Share, to all the rights and
preferences of the Preferred Stock underlying that Depositary Share. Those
rights include dividend, voting, redemption, conversion and liquidation rights.

         The Depositary Shares will be evidenced by depositary receipts issued
pursuant to the Deposit Agreement ("Depositary Receipts"). Depositary Receipts
will be issued to those persons who purchase the fractional interests in the
Preferred Stock underlying the Depositary Shares, in accordance with the terms
of the offering. Copies of the forms of Deposit Agreement and Depositary Receipt
are filed as exhibits to the registration statement. The following summary of
the Deposit Agreement, the Depositary Shares and the Depositary Receipts is not
complete. You should refer to the forms of the Deposit Agreement and Depositary
Receipts that are filed as exhibits to the registration statement.

         Dividends and Other Distributions. The Depositary will distribute all
cash dividends or other cash distributions received in respect of the Preferred
Stock to the record holders of Depositary Shares relating to that Preferred
Stock in proportion to the number of Depositary Shares owned by those holders.

         If there is a distribution other than in cash, the Depositary will
distribute property received by it to the record holders of Depositary Shares
that are entitled to receive the distribution, unless the Depositary determines
that it is not feasible to make the distribution. If this occurs, the Depositary
may, with our approval, sell the property and distribute the net proceeds from
the sale to the applicable holders.

                                       14

<PAGE>   18




         Redemption of Depositary Shares. If a series of Preferred Stock
underlying the Depositary Shares is subject to redemption, the Depositary Shares
will be redeemed from the proceeds received by the Depositary resulting from the
redemption, in whole or in part, of that series of Preferred Stock held by the
Depositary. The redemption price per Depositary Share will be equal to the
applicable fraction of the redemption price per share payable with respect to
that series of the Preferred Stock. Whenever we redeem shares of Preferred Stock
that are held by the Depositary, the Depositary will redeem, as of the same
redemption date, the number of Depositary Shares representing the shares of
Preferred Stock so redeemed. If fewer than all the Depositary Shares are to be
redeemed, the Depositary Shares to be redeemed will be selected by lot or pro
rata as determined by the Depositary.

         After the date fixed for redemption, the Depositary Shares called for
redemption will no longer be outstanding, and all rights of the holders of those
Depositary Shares will cease, except the right to receive any money, securities,
or other property upon surrender to the Depositary of the Depositary Receipts
evidencing those Depositary Shares.

         Voting the Preferred Stock. Upon receipt of notice of any meeting at
which the holders of Preferred Stock are entitled to vote, the Depositary will
mail the information contained in the notice of meeting to the record holders of
the Depositary Shares underlying that Preferred Stock. Each record holder of
those Depositary Shares on the record date (which will be the same date as the
record date for the Preferred Stock) will be entitled to instruct the Depositary
as to the exercise of the voting rights pertaining to the amount of the
Preferred Stock underlying that holder's Depositary Shares. The Depositary will
try, as far as practicable, to vote the number of shares of Preferred Stock
underlying those Depositary Shares in accordance with such instructions, and we
will agree to take all action which may be deemed necessary by the Depositary in
order to enable the Depositary to do so. The Depositary will not vote the shares
of Preferred Stock to the extent it does not receive specific instructions from
the holders of Depositary Shares underlying the Preferred Stock.

         Amendment and Termination of the Depositary Agreement. The form of
Depositary Receipt evidencing the Depositary Shares and any provision of the
Deposit Agreement may be amended at any time by agreement between us and the
Depositary. However, any amendment that materially and adversely alters the
rights of the holders of Depositary Shares will not be effective unless the
amendment has been approved by the holders of at least a majority of the
Depositary Shares then outstanding. The Deposit Agreement may be terminated by
us or by the Depositary only if (i) all outstanding Depositary Shares have been
redeemed or (ii) there has been a final distribution of the underlying Preferred
Stock in connection with our liquidation, dissolution or winding up and the
Preferred Stock has been distributed to the holders of Depositary Receipts.

         Resignation and Removal of Depositary. The Depositary may resign at any
time by delivering a notice to us of its election to do so. We may remove the
Depositary at any time. Any such resignation or removal will take effect upon
the appointment of a successor Depositary and its acceptance of its appointment.
The successor Depositary must be appointed within 60 days after delivery of the
notice of resignation or removal.

         Miscellaneous. The Depositary will forward to holders of Depository
Receipts all reports and communications from us that we deliver to the
Depositary and that we are required to furnish to the holders of the Preferred
Stock.

         Neither we nor the Depositary will be liable if either of us is
prevented or delayed by law or any circumstance beyond our control in performing
our respective obligations under the Deposit Agreement. Our obligations and
those of the Depositary will be limited to the performance in good faith of our
respective duties under the Deposit Agreement. Neither we nor the Depositary
will be obligated to prosecute or defend any legal proceeding in respect of any
Depositary Shares or Preferred Stock unless satisfactory indemnity is furnished.
We and the Depositary may rely upon written advice of counsel or accountants, or
upon information provided by persons presenting Preferred Stock for deposit,
holders of Depositary Receipts or other persons believed to be competent and on
documents believed to be genuine.

                                       15

<PAGE>   19




         Description of Permanent Global Preferred Securities.

         Certain series of the Preferred Stock or Depositary Shares may be
issued as permanent global securities to be deposited with a depositary with
respect to that series. Unless otherwise indicated in the Prospectus Supplement,
the following is a summary of the depositary arrangements applicable to
Preferred Stock or Depositary Receipts issued in permanent global form and for
which DTC acts as the depositary ("Global Preferred Securities").

         Each Global Preferred Security will be deposited with, or on behalf of,
DTC or its nominee and registered in the name of a nominee of DTC. Except under
the limited circumstances described below, Global Preferred Securities are not
exchangeable for definitive certificated Preferred Stock or Depositary Receipts.

         Ownership of beneficial interests in a Global Preferred Security is
limited to institutions that have accounts with DTC or its nominee
("participants") or persons that may hold interests through participants. In
addition, ownership of beneficial interests by participants in a Global
Preferred Security will be evidenced only by, and the transfer of that ownership
interest will be effected only through, records maintained by DTC or its nominee
for a Global Preferred Security. Ownership of beneficial interests in a Global
Preferred Security by persons that hold through participants will be evidenced
only by, and the transfer of that ownership interest within that participant
will be effected only through, records maintained by that participant. DTC has
no knowledge of the actual beneficial owners of the Preferred Stock or
Depositary Shares, as the case may be, represented by a Global Preferred
Security. Beneficial owners will not receive written confirmation from DTC of
their purchase, but beneficial owners are expected to receive written
confirmations providing details of the transaction, as well as periodic
statements of their holdings, from the participants through which the beneficial
owners entered the transaction. The laws of some jurisdictions require that
certain purchasers of securities take physical delivery of such securities in
definitive form. Such laws may impair the ability to transfer beneficial
interests in a Global Preferred Security.

         Payments on Preferred Stock and Depositary Shares represented by a
Global Preferred Security registered in the name of or held by DTC or its
nominee will be made to DTC or its nominee, as the case may be, as the
registered owner and holder of the Global Preferred Security representing the
Preferred Stock or Depositary Shares. We have been advised by DTC that upon
receipt of any payment on a Global Preferred Security, DTC will immediately
credit accounts of participants on its book-entry registration and transfer
system with payments in amounts proportionate to their respective beneficial
interests in that Global Preferred Security as shown in the records of DTC.
Payments by participants to owners of beneficial interests in a Global Preferred
Security held through those participants will be governed by standing
instructions and customary practices, as is now the case with securities held
for the accounts of customers in bearer form or registered in "street name", and
will be the sole responsibility of those participants, subject to any statutory
or regulatory requirements as may be in effect from time to time.

         Neither we nor any of our agents will be responsible for any aspect of
the records of DTC, any nominee or any participant relating to, or payments made
on account of beneficial interests in a Global Preferred Security or for
maintaining, supervising or reviewing any of the records of DTC, any nominee or
any participant relating to such beneficial interests.

         A Global Preferred Security is exchangeable for definitive certificated
Preferred Stock or Depositary Receipts, as the case may be, registered in the
name of, and a transfer of a Global Preferred Security may be registered to, a
person other than DTC or its nominee, only if:

         o        DTC notifies us that it is unwilling or unable to continue as
                  Depositary for the Global Preferred Security or at any time
                  DTC ceases to be registered under the Exchange Act; or

         o        We determine in our discretion that the Global Preferred
                  Security shall be exchangeable for definitive Preferred Stock
                  or Depositary Receipts, as the case may be, in registered
                  form.

         Any Global Preferred Security that is exchangeable pursuant to the
preceding sentence will be exchangeable in whole for definitive certificated
Preferred Stock or Depositary Receipts, as the case may be, registered by the
registrar in the name or names instructed by DTC. We expect that those
instructions may be based

                                       16

<PAGE>   20




upon directions received by DTC from its participants with respect to ownership
of beneficial interests in that Global Preferred Security.

         Except as provided above, owners of the beneficial interests in a
Global Preferred Security will not be entitled to receive physical delivery of
certificates representing shares of Preferred Stock or Depositary Shares, as the
case may be, and will not be considered the holders of Preferred Stock or
Depositary Shares, as the case may be. No Global Preferred Security shall be
exchangeable except for another Global Preferred Security to be registered in
the name of DTC or its nominee. Accordingly, each person owning a beneficial
interest in a Global Preferred Security must rely on the procedures of DTC and,
if that person is not a participant, on the procedures of the participant
through which that person owns its interest, to exercise any rights of a holder
of Preferred Stock or Depositary Shares, as the case may be.

         We understand that, under existing industry practices, in the event
that we request any action of holders, or an owner of a beneficial interest in a
Global Preferred Security desires to give or take any action that a holder of
Preferred Stock or Depositary Shares, as the case may be, is entitled to give or
take, DTC would authorize the participants holding the relevant beneficial
interests to give or take that action and those participants would authorize
beneficial owners owning through those participants to give or take that action
or would otherwise act upon the instructions of beneficial owners owning through
them.

         A brief description of DTC is set forth above under "Description of
Debt Securities-Permanent Global Debt Securities."

WARRANTS

         We may issue Warrants for the purchase of Debt Securities, Preferred
Stock or Common Stock. We may issue Warrants alone or together with any other
securities. Each series of Warrants will be issued under a separate Warrant
Agreement (each a "Warrant Agreement") to be entered into between us and a
Warrant Agent ("Warrant Agent"). The Warrant Agent will act solely as our agent
in connection with the Warrant of such series and will not assume any obligation
or relationship of agency for or with holders or beneficial owners of Warrants.
Further terms of the Warrants and the applicable Warrant Agreement will be set
forth in the applicable Prospectus Supplement.

FOREIGN OWNERSHIP

         The Certificate of Incorporation contains provisions that limit foreign
ownership of our capital stock. These provisions protect our ability to continue
to own our mobile offshore drilling units as U.S. flag vessels and to comply
with certain financial covenants that require us to maintain U.S. citizenship
that are contained in certain of our financing agreements.

         In order to continue to enjoy the benefits of U.S. flag registry for
our vessels, we must maintain "United States citizenship" as defined in the
Shipping Act, 1916, as amended (the "Shipping Act"). A corporation is not
considered a U.S. citizen for these purposes unless, among other things, the
controlling interest of the corporation (a majority in the case of non-coastwise
trade) is owned by U.S. citizens. Under regulations adopted by the U.S. Maritime
Administration to implement the citizenship requirements, the "controlling
interest" test is applied to each class of our stock. The Common Stock and
Preferred Stock (combining all series of Preferred Stock) are considered to be
separate classes of capital stock for this purpose.

         Under the provisions of the Certificate of Incorporation, (i) any
transfer, or attempted or purported transfer, of any shares of our capital stock
that would result in the ownership or control by one or more persons who is not
a U.S. citizen for purposes of the Shipping Act of an aggregate percentage of
the shares of any class of capital stock in excess of a fixed percentage (the
"Permitted Percentage") that is equal to 90% of the percentage that would
prevent us from being a U.S. citizen (currently 50%) for purposes of the
Shipping Act, will, for so long as such excess shall exist, be void and
ineffective as against us, and (ii) if at any time ownership of shares of our
capital stock (either of record or beneficial) by persons other than U.S.
citizens exceeds the Permitted Percentage, we may withhold payment of dividends
on such shares determined to be in excess of the Permitted Percentage and may
suspend voting rights attributable to such shares. The shares subject to any
such withholding of dividends or

                                       17

<PAGE>   21




suspension of voting rights would be those foreign-owned shares that our Board
of Directors determines became so owned most recently. The Permitted Percentage
is currently 45%.

PREFERRED STOCK PURCHASE RIGHTS

         We have a stockholder rights plan which was adopted in 1995 and amended
in 1997. Under this plan, one Right (a "Right") is attached to each outstanding
share of Common Stock. The Rights are exercisable only if a person or group of
affiliated or associated persons acquires beneficial ownership of 15 % or more
of our outstanding Common Stock or announces a tender offer, the consummation of
which would result in ownership by a person or group of 15% or more of our
Common Stock. Each Right entitles the registered holder to purchase from us one
one-hundredth of a share of Series A Junior Participating Preferred Stock at an
exercise price of $120.00. The existence of the Rights may, under certain
circumstances, render more difficult or discourage attempts to acquire us.


                              PLAN OF DISTRIBUTION

         We may sell the offered securities (a) through agents; (b) through
underwriters or dealers; or (c) directly to one or more purchasers.

BY AGENTS

         Offered securities may be sold through agents designated by us. The
agents agree to use their reasonable best efforts to solicit purchases for the
period of their appointment.

BY UNDERWRITERS

         If underwriters are used in the sale, the offered securities will be
acquired by the underwriters for their own account. The underwriters may resell
the securities in one or more transactions, including negotiated transactions,
at a fixed public offering price or at varying prices determined at the time of
sale. The obligations of the underwriters to purchase the securities will be
subject to certain conditions. The underwriters will be obligated to purchase
all the securities of the series offered if any of the securities are purchased.
Any initial public offering price and any discounts or concessions allowed or
re-allowed or paid to dealers may be changed from time to time.

DIRECT SALES

         Offered securities may also be sold directly by us. In this case, no
underwriters or agents would be involved.

GENERAL INFORMATION

         Underwriters, dealers and agents that participate in the distribution
of the offered securities may be underwriters as defined in the Securities Act
of 1933 (the "Act"), and any discounts or commissions received by them from us
and any profit on the resale of the offered securities by them may be treated as
underwriting discounts and commissions under the Act. Any underwriters or agents
will be identified and their compensation described in a Prospectus Supplement.

         We may have agreements with the underwriters, dealers and agents to
indemnify them against certain civil liabilities, including liabilities under
the Act, or to contribute with respect to payments which the underwriters,
dealers or agents may be required to make.

         Underwriters, dealers and agents may engage in transactions with, or
perform services for, us or our subsidiaries in the ordinary course of their
businesses.

                                       18

<PAGE>   22




                                  LEGAL MATTERS

         Certain legal matters in connection with the Debt Securities we are
offering pursuant to this Prospectus will be passed upon for us by our counsel,
Thompson & Knight, P.C., located at 1700 Pacific Avenue, Suite 3300, Dallas,
Texas 75201.


                                     EXPERTS

         The consolidated financial statements incorporated in this Prospectus
by reference to the Annual Report on Form 10-K for the year ended December 31,
1997, have been so incorporated in reliance on the report of
PricewaterhouseCoopers LLP, independent accountants, given on the authority of
said firm as experts in auditing and accounting.

                                       19

<PAGE>   23








                                     [LOGO]




                                  $300,000,000


                                 DEBT SECURITIES
                                  COMMON STOCK
                                 PREFERRED STOCK
                                    WARRANTS




                                 --------------

                                   PROSPECTUS

                                 --------------

















<PAGE>   24




                                   P A R T II

                     INFORMATION NOT REQUIRED IN PROSPECTUS

ITEM 14.  OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION.

         Except for the SEC registration fee and the NASD filing fee, all
expenses are estimated. All such expenses will be paid by the Registrant.

<TABLE>
<S>                                                                                  <C>                   
SEC registration fee...............................................................  $               83,400
Accounting fees and expenses.......................................................                  60,000
Legal fees and expenses............................................................                  85,000
Printing expenses..................................................................                  50,000
Blue sky fees and expenses (including legal fees)..................................                  10,000
Miscellaneous......................................................................                  11,600
                                                                                     ----------------------
         Total.....................................................................  $              300,000
                                                                                     ======================
</TABLE>


ITEM 15.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.

         The Registrant is a Delaware corporation. Under Section 145 of the
General Corporation Law of the State of Delaware, the Registrant has the power
to indemnify its directors and officers, subject to certain limitations.

         Reference is made to Article VI of the Bylaws of the Registrant, which
Article is filed as part of Exhibit 4.8 hereto and provides for indemnification
of directors and officers of the Registrant under certain circumstances.

         The Registrant anticipates that any underwriting agreement will include
provisions relating to the indemnification of directors, officers and
controlling persons of the Registrant against certain liabilities, including
liabilities under the Securities Act of 1933.

         Pursuant to the General Corporation Law of the State of Delaware, the
Certificate of Incorporation of the Registrant, filed as Exhibits 4.1 through
4.8 hereto, limits the personal liability of the directors of the Registrant to
the Registrant or its stockholders for monetary damages for breach of fiduciary
duty under certain circumstances.

         The Registrant has entered into an indemnity agreement with each of its
directors and officers to supplement the indemnification protection available
under the statute, bylaws and certificate of incorporation referred to above.
These indemnity agreements generally provide that the Registrant will indemnify
the parties thereto to the fullest extent permitted by law. The indemnity
agreements were approved and ratified by stockholders of the Registrant in 1996.

         The Registrant also maintains insurance to protect itself and its
directors, officers, employees and agents against expenses, liabilities and
losses incurred by such persons in connection with their service in the
foregoing capacities.

         The foregoing summaries are necessarily subject to the complete text of
the statute, bylaw, agreements, certificate of incorporation and insurance
policy referred to above and are qualified in their entirety by reference
thereto.


                                      II-1

<PAGE>   25

ITEM 16.  EXHIBITS.


         The following exhibits are filed as part of this Registration
Statement:


      NUMBER                         EXHIBIT

       1.1          --       Underwriting Agreement.

       4.1          --       Restated Certificate of Incorporation of the
                             Registrant dated August 29, 1985 (filed as Exhibit
                             3.7 to the Registrant's Registration Statement on
                             Form 10 (No. 0-13857) and incorporated herein by
                             reference).

       4.2          --       Certificate of Amendment of Restated Certificate of
                             Incorporation of the Registrant dated May 5, 1987
                             (filed as Exhibit 4.2 to the Registrant's
                             Registration Statement on Form S-3 (No. 33-67130)
                             and incorporated herein by reference).

       4.3          --       Certificate of Amendment of Restated Certificate of
                             Incorporation of the Registrant dated July 31,
                             1991(filed as Exhibit 3.16 to the Registrant's
                             Annual Report on Form 10-K for the year ended
                             December 31, 1991 and incorporated herein by
                             reference).

       4.4          --       Certificate of Amendment of Restated Certificate of
                             Incorporation of the Registrant dated September 15,
                             1994 (filed as Exhibit 3.1 to the Registrant's
                             Quarterly Report on Form 10-Q for the three-month
                             period ended March 31, 1995 and incorporated herein
                             by reference).

       4.5          --       Certificate of Designations of Series A Junior
                             Participating Preferred Stock, par value $1.00 per
                             share, of the Registrant dated as of June 29, 1995
                             (filed as Exhibit 3.2 to the Registrant's Quarterly
                             Report on Form 10-Q for the three-month period
                             ended June 30, 1995 and incorporated herein by
                             reference).

       4.6          --       Certificate of Amendment of Certificate of
                             Designations of Series A Junior Participating
                             Preferred Stock of Registrant dated September 5,
                             1997 (filed as Exhibit 3.6 to the Registrant's
                             Annual Report on Form 10-K for the year ended
                             December 31, 1997 and incorporated herein by
                             reference).

       4.7          --       Composite copy of the Bylaws of the Registrant as
                             currently in effect (filed as Exhibit 3.7 to the
                             Registrant's Annual Report on Form 10-K for the
                             year ended December 31, 1997 and incorporated
                             herein by reference).

       4.8          --       Amendment of Articles IV and VI of the Bylaws of
                             the Registrant adopted January 29, 1998 (filed as
                             Exhibit 3.8 to the Registrant's Form 10-K/A
                             (Amendment No. 1) dated June 29, 1998 and
                             incorporated herein by reference).

       4.9          --       Form of Senior Indenture.

       4.10         --       Form of Subordinated Indenture.

       4.11         --       First Supplemental Indenture dated as of May 30,
                             1997 to Indenture dated as of October 1, 1993
                             governing the 9 1/4% Senior Notes due 2003 (filed
                             as Exhibit 4.2 to the Registrant's Annual Report on
                             Form 10-K for the year ended December 31, 1997 and
                             incorporated herein by reference).

       4.12         --       Indenture dated as of July 1, 1996 governing the 9
                             1/8% Senior Notes due 2006 (including form of
                             Note)(filed as Exhibit 4.1 to the Registrant's Form
                             8-K dated July 16, 1996 (date of event: July 1,
                             1996) and incorporated herein by reference).


                                      II-2


<PAGE>   26





       4.13         --       Credit Agreement, dated as of August 14, 1997,
                             among Noble Drilling Corporation, the lending
                             institutions listed from time to time on Annex I
                             thereto, Credit Lyonnais New York Branch, as
                             Documentation Agent and Christiania Bank Og
                             Kreditkasse ASA, New York Branch, as Arranger and
                             Administrative Agent (filed as Exhibit 4.4 to the
                             Registrant's Annual Report on Form 10-K for the
                             year ended December 31, 1997 and incorporated
                             herein by reference).

       4.14         --       Rights Agreement dated as of June 28, 1995 between
                             the Registrant and Liberty Bank and Trust Company
                             of Oklahoma City, N.A. (filed as Exhibit 4 to the
                             Registrant's Form 8-K dated June 29, 1995 (date of
                             event: June 28, 1995) and incorporated herein by
                             reference).

       4.15         --       Amendment No. 1 to Rights Agreement, dated
                             September 3, 1997, between Noble Drilling
                             Corporation and Liberty Bank and Trust Company of
                             Oklahoma City, N.A. (filed as Exhibit 4.2 to the
                             Registrant's Form 8-A/A (Amendment No. 1) dated
                             September 3, 1997 and incorporated herein by
                             reference).

       4.16         --       Summary of Rights to Purchase Preferred Shares, as
                             amended as of September 3, 1997 to conform with
                             Amendment No. 1 to Rights Agreement, dated
                             September 3, 1997 (filed as Exhibit 4.3 to the
                             Registrant's Form 8-K dated September 3, 1997 (date
                             of event: September 3, 1997) and incorporated
                             herein by reference).

       4.17         --       Note Purchase Agreement dated as of September 24,
                             1998, by and among Noble Drilling (Paul Romano)
                             Inc. and each of the note purchasers thereunder.
                             Each note purchaser has entered into a separate
                             Note Purchase Agreement, which agreements are
                             substantially identical in all material respects,
                             except for the principal amount of notes purchased.
                             A schedule identifying each of the note purchasers
                             that entered into a Note Purchase Agreement with
                             Noble Drilling (Paul Romano) Inc. and the principal
                             amount of notes to be purchased by each such note
                             purchaser is included as Schedule A to the Note
                             Purchase Agreement (filed as Exhibit 4.1 to the
                             Registrant's Form 10-Q for the three-month period
                             ended September 30, 1998 and incorporated herein by
                             reference).

       4.18         --       Form of Indenture and Security Agreement to be
                             entered into between Noble Drilling (Paul Romano)
                             Inc. and Chase Bank of Texas, National Association,
                             as Trustee (filed as Exhibit 4.2 to the
                             Registrant's Form 10-Q for the three-month period
                             ended September 30, 1998 and incorporated herein by
                             reference).

       4.19         --       Form of First Naval Mortgage covering the Noble
                             Paul Romano to be made by Noble Drilling (Paul
                             Romano) Inc. in favor of Chase Bank of Texas,
                             National Association, as Indenture Trustee (filed
                             as Exhibit 4.3 to the Registrant's Form 10-Q for
                             the three-month period ended September 30, 1998 and
                             incorporated herein by reference).

       4.20         --       Note Purchase Agreement dated as of July 1, 1998,
                             by and among Noble Drilling (Paul Wolff) Ltd.,
                             Chase Bank of Texas, National Association, as
                             Trustee, and each of the note purchasers
                             thereunder. Each note purchaser has entered into a
                             separate Note Purchase Agreement, which agreements
                             are substantially identical in all material
                             respects, except for the principal amount of notes
                             purchased. A schedule identifying each of the note
                             purchasers that entered into a Note Purchase
                             Agreement with Noble Drilling (Paul Wolff) Ltd. and
                             the principal amount of notes purchased by each
                             such note purchaser is included as Annex I to the
                             Note Purchase Agreement (filed as Exhibit 4.4 to
                             the Registrant's Form 10-Q for the three-month
                             period ended September 30, 1998 and incorporated
                             herein by reference).

       4.21         --       Indenture of First Naval Mortgage, dated as of July
                             1, 1998, made by Noble Drilling (Paul Wolff) Ltd.
                             in favor of Chase Bank of Texas, National
                             Association, as Trustee (filed as Exhibit 4.5 to
                             the Registrant's Form 10-Q for the three-month
                             period ended September 30, 1998 and incorporated
                             herein by reference).

                                      II-3


<PAGE>   27



       4.22         --       Parent Guaranty, dated as of July 1, 1998, by Noble
                             Drilling Corporation in favor of Chase Bank of
                             Texas, National Association, as Trustee (filed as
                             Exhibit 4.6 to the Registrant's Form 10-Q for the
                             three-month period ended September 30, 1998 and
                             incorporated herein by reference).

       4.23         --       Second Amendment, dated September 10, 1998, to
                             Credit Agreement, dated as of August 14, 1997,
                             among Noble Drilling Corporation, the lending
                             institutions listed from time to time on Annex I
                             thereto, Credit Lyonnais, New York Branch, as
                             Documentation Agent, and Christiana Bank Og
                             Kreditkasse ASA, New York Branch, as Administrative
                             Agent (filed as Exhibit 4.7 to the Registrant's
                             Form 10-Q for the three-month period ended
                             September 30, 1998 and incorporated herein by
                             reference).

       5.1          --       Opinion of Thompson & Knight, A Professional
                             Corporation.

       12.1         --       Statement re Computation of Ratio of Earnings to
                             Fixed Charges.

       23.1         --       Consent of PricewaterhouseCoopers LLP.

       23.2         --       Consent of Thompson & Knight, A Professional
                             Corporation (contained in its opinion filed as
                             Exhibit 5.1).

       24.1         --       Powers of Attorney (included on signature page).

       25.1         --       Form T-1 Statement of Eligibility and Qualification
                             under the Trust Indenture Act of 1939, as amended, 
                             with respect to Trustee for Senior Debt Securities.

       25.2         --       Form T-1 Statement of Eligibility and Qualification
                             under the Trust Indenture Act of 1939, as amended, 
                             with respect to Trustee for Subordinated Debt 
                             Securities.

       *        To be filed by amendment or by Form 8-K.

ITEM 17.  UNDERTAKINGS.

         (b)      Filings incorporating subsequent Exchange Act documents by
reference.

         The undersigned Registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act of 1933, each filing of the
Registrant's Annual Report pursuant to Section 13(a) or Section 15(d) of the
Securities Exchange Act of 1934 that is incorporated by reference in the
Registration Statement shall be deemed to be a new registration statement
relating to the securities offered therein, and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof.

         (h)      Acceleration of effectiveness.

         Insofar as indemnification for liabilities arising under the Securities
Act of 1933 may be permitted to directors, officers and controlling persons of
the Registrant pursuant to the foregoing provisions, or otherwise, the
Registrant has been advised that in the opinion of the SEC such indemnification
is against public policy as expressed in the Act and is, therefore,
unenforceable. In the event that a claim for indemnification against such
liabilities (other than the payment by the Registrant of expenses incurred or
paid by a director, officer or controlling person of the Registrant in the
successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Registrant will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against public
policy as expressed in the Act and will be governed by the final adjudication of
such issue.

         (i)      Rule 430A.

         The undersigned Registrant hereby undertakes that:

                  (1) For purposes of determining any liability under the
Securities Act of 1933, the information omitted from the form of prospectus
filed as part of this Registration Statement in reliance upon Rule 430A and

                                      II-4

<PAGE>   28




contained in a form of prospectus filed by the Registrant pursuant to Rule
424(b)(1) or (4) or 497(h) under the Securities Act shall be deemed to be part
of this Registration Statement as of the time it was declared effective.

                  (2) For the purpose of determining any liability under the
Securities Act of 1933, each post-effective amendment that contains a form of
prospectus shall be deemed to be a new registration statement relating to the
securities offered therein, and the offering of such securities at that time
shall be deemed to be the initial bona fide offering thereof.

                                      II-5

<PAGE>   29




                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, the
Registrant certifies that it has reasonable grounds to believe that it meets all
of the requirements for filing on Form S-3 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Houston, State of Texas, on the 7th day of December,
1998.

                                     NOBLE DRILLING CORPORATION



                                     By: /s/ James C. Day
                                        ------------------------------------
                                                   James C. Day
                                 Chairman, President and Chief Executive Officer


         Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated. Each person whose signature appears below
constitutes and appoints James C. Day and Byron L. Welliver, and each of them
(with full power to each of them to act alone), his true and lawful
attorney-in-fact and agent, with full power of substitution and resubstitution,
for him and in his name, place and stead, in any and all capacities to sign on
his behalf individually and in each capacity stated below any amendment,
including post-effective amendments, to this Registration Statement, and to file
the same, with all exhibits thereto and other documents in connection therewith
with the SEC, granting unto said attorneys-in-fact and agents, and each of them,
full power and authority to do and perform each and every act and thing
requisite and necessary to be done in and about the premises, as fully to all
intents and purposes as he might or could do in person, hereby ratifying and
confirming all that said attorneys-in-fact and agents and either of them, or
their substitutes, may lawfully do or cause to be done by virtue hereof.

<TABLE>
<CAPTION>
                    SIGNATURE                                       TITLE                              DATE
                    ---------                                       -----                              ----


<S>                                               <C>                                            <C>
                /s/ James C. Day                  Chairman, President and Chief                  December 7, 1998
- ----------------------------------------------    Executive Officer and Director
                  James C. Day                    (Principal Executive Officer)


              /s/ Byron L. Welliver               Senior Vice President - Finance,               December 7, 1998
- ----------------------------------------------    Treasurer and Controller (Principal
                Byron L. Welliver                 Financial and Accounting Officer)


              /s/ Michael A. Cawley               Director                                       December 7, 1998
- ----------------------------------------------
                Michael A. Cawley


             /s/ Lawrence J. Chazen               Director                                       December 7, 1998
- ----------------------------------------------
               Lawrence J. Chazen


             /s/ Tommy C. Craighead               Director                                       December 7, 1998
- ----------------------------------------------
               Tommy C. Craighead
</TABLE>




                                      II-6

<PAGE>   30




<TABLE>
<S>                                               <C>                                            <C>
               /s/ William J. Dore                Director                                       December 7, 1998
- ----------------------------------------------
                 William J. Dore


               /s/ James L. Fishel                Director                                       December 7, 1998
- ----------------------------------------------
                 James L. Fishel


               /s/ Marc E. Leland                 Director                                       December 7, 1998
- ----------------------------------------------
                 Marc E. Leland


              /s/ William A. Sears                Director                                       December 7, 1998
- ----------------------------------------------
                William A. Sears
</TABLE>

                                      II-7

<PAGE>   31


                               INDEX TO EXHIBITS



<TABLE>
<CAPTION>
     EXHIBIT
     NUMBER                 DESCRIPTION
     ------                 -----------

<S>                          <C>
       1.1*         --       Underwriting Agreement.

       4.1          --       Restated Certificate of Incorporation of the Registrant dated August 29, 1985
                             (filed as Exhibit 3.7 to the Registrant's Registration Statement on Form 10 (No.
                             0-13857) and incorporated herein by reference).

       4.2          --       Certificate of Amendment of Restated Certificate of Incorporation of the
                             Registrant dated May 5, 1987 (filed as Exhibit 4.2 to the Registrant's
                             Registration Statement on Form S-3 (No. 33-67130) and incorporated herein by
                             reference).

       4.3          --       Certificate of Amendment of Restated Certificate of Incorporation of the
                             Registrant dated July 31, 1991(filed as Exhibit 3.16 to the Registrant's Annual
                             Report on Form 10-K for the year ended December 31, 1991 and incorporated herein
                             by reference).

       4.4          --       Certificate of Amendment of Restated Certificate of Incorporation of the
                             Registrant dated September 15, 1994 (filed as Exhibit 3.1 to the Registrant's
                             Quarterly Report on Form 10-Q for the three-month period ended March 31, 1995 and
                             incorporated herein by reference).

       4.5          --       Certificate of Designations of Series A Junior Participating Preferred Stock, par
                             value $1.00 per share, of the Registrant dated as of June 29, 1995 (filed as
                             Exhibit 3.2 to the Registrant's Quarterly Report on Form 10-Q for the three-month
                             period ended June 30, 1995 and incorporated herein by reference).

       4.6          --       Certificate of Amendment of Certificate of Designations of Series A Junior
                             Participating Preferred Stock of Registrant dated September 5, 1997 (filed as
                             Exhibit 3.6 to the Registrant's Annual Report on Form 10-K for the year ended
                             December 31, 1997 and incorporated herein by reference).

       4.7          --       Composite copy of the Bylaws of the Registrant as currently in effect (filed as
                             Exhibit 3.7 to the Registrant's Annual Report on Form 10-K for the year ended
                             December 31, 1997 and incorporated herein by reference).

       4.8          --       Amendment of Articles IV and VI of the Bylaws of the Registrant adopted January
                             29, 1998 (filed as Exhibit 3.8 to the Registrant's Form 10-K/A (Amendment No. 1)
                             dated June 29, 1998 and incorporated herein by reference).

       4.9          --       Form of Senior Indenture.

       4.10         --       Form of Subordinated Indenture.

       4.11         --       First Supplemental Indenture dated as of May 30, 1997 to Indenture dated as of
                             October 1, 1993 governing the 9 1/4% Senior Notes due 2003 (filed as Exhibit 4.2
                             to the Registrant's Annual Report on Form 10-K for the year ended December 31,
                             1997 and incorporated herein by reference).

       4.12         --       Indenture dated as of July 1, 1996 governing the 9 1/8% Senior Notes due 2006
                             (including form of Note)(filed as Exhibit 4.1 to the Registrant's Form 8-K dated
                             July 16, 1996 (date of event: July 1, 1996) and incorporated herein by
                             reference).
</TABLE>




<PAGE>   32





<TABLE>
<S>                          <C>
       4.13         --       Credit Agreement, dated as of August 14, 1997, among Noble Drilling Corporation,
                             the lending institutions listed from time to time on Annex I thereto, Credit
                             Lyonnais New York Branch, as Documentation Agent and Christiania Bank Og
                             Kreditkasse ASA, New York Branch, as Arranger and Administrative Agent (filed as
                             Exhibit 4.4 to the Registrant's Annual Report on Form 10-K for the year ended
                             December 31, 1997 and incorporated herein by reference).

       4.14         --       Rights Agreement dated as of June 28, 1995 between the Registrant and Liberty
                             Bank and Trust Company of Oklahoma City, N.A. (filed as Exhibit 4 to the
                             Registrant's Form 8-K dated June 29, 1995 (date of event: June 28, 1995) and
                             incorporated herein by reference).

       4.15         --       Amendment No. 1 to Rights Agreement, dated September 3, 1997, between Noble
                             Drilling Corporation and Liberty Bank and Trust Company of Oklahoma City, N.A.
                             (filed as Exhibit 4.2 to the Registrant's Form 8-A/A (Amendment No. 1) dated
                             September 3, 1997 and incorporated herein by reference).

       4.16         --       Summary of Rights to Purchase Preferred Shares, as amended as of September 3,
                             1997 to conform with Amendment No. 1 to Rights Agreement, dated September 3, 1997
                             (filed as Exhibit 4.3 to the Registrant's Form 8-K dated September 3, 1997 (date
                             of event: September 3, 1997) and incorporated herein by reference).

       4.17         --       Note Purchase Agreement dated as of September 24, 1998, by and among Noble
                             Drilling (Paul Romano) Inc. and each of the note purchasers thereunder. Each note
                             purchaser has entered into a separate Note Purchase Agreement, which agreements
                             are substantially identical in all material respects, except for the principal
                             amount of notes purchased. A schedule identifying each of the note purchasers
                             that entered into a Note Purchase Agreement with Noble Drilling (Paul Romano)
                             Inc. and the principal amount of notes to be purchased by each such note
                             purchaser is included as Schedule A to the Note Purchase Agreement (filed as
                             Exhibit 4.1 to the Registrant's Form 10-Q for the three-month period ended
                             September 30, 1998 and incorporated herein by reference).

       4.18         --       Form of Indenture and Security Agreement to be entered into between Noble
                             Drilling (Paul Romano) Inc. and Chase Bank of Texas, National Association, as
                             Trustee (filed as Exhibit 4.2 to the Registrant's Form 10-Q for the three-month
                             period ended September 30, 1998 and incorporated herein by reference).

       4.19         --       Form of First Naval Mortgage covering the Noble Paul Romano to be made by Noble
                             Drilling (Paul Romano) Inc. in favor of Chase Bank of Texas, National
                             Association, as Indenture Trustee (filed as Exhibit 4.3 to the Registrant's Form
                             10-Q for the three-month period ended September 30, 1998 and incorporated herein
                             by reference).

       4.20         --       Note Purchase Agreement dated as of July 1, 1998, by and among Noble Drilling
                             (Paul Wolff) Ltd., Chase Bank of Texas, National Association, as Trustee, and
                             each of the note purchasers thereunder. Each note purchaser has entered into a
                             separate Note Purchase Agreement, which agreements are substantially identical in
                             all material respects, except for the principal amount of notes purchased. A
                             schedule identifying each of the note purchasers that entered into a Note
                             Purchase Agreement with Noble Drilling (Paul Wolff) Ltd. and the principal amount
                             of notes purchased by each such note purchaser is included as Annex I to the Note
                             Purchase Agreement (filed as Exhibit 4.4 to the Registrant's Form 10-Q for the
                             three-month period ended September 30, 1998 and incorporated herein by
                             reference).

       4.21         --       Indenture of First Naval Mortgage, dated as of July 1, 1998, made by Noble
                             Drilling (Paul Wolff) Ltd. in favor of Chase Bank of Texas, National Association,
                             as Trustee (filed as Exhibit 4.5 to the Registrant's Form 10-Q for the
                             three-month period ended September 30, 1998 and incorporated herein by
                             reference).
</TABLE>


<PAGE>   33





<TABLE>
<S>                          <C>
       4.22         --       Parent Guaranty, dated as of July 1, 1998, by Noble Drilling Corporation in favor
                             of Chase Bank of Texas, National Association, as Trustee (filed as Exhibit 4.6 to
                             the Registrant's Form 10-Q for the three-month period ended September 30, 1998
                             and incorporated herein by reference).

       4.23         --       Second Amendment, dated September 10, 1998, to Credit Agreement, dated as of
                             August 14, 1997, among Noble Drilling Corporation, the lending institutions
                             listed from time to time on Annex I thereto, Credit Lyonnais, New York Branch, as
                             Documentation Agent, and Christiana Bank Og Kreditkasse ASA, New York Branch, as
                             Administrative Agent (filed as Exhibit 4.7 to the Registrant's Form 10-Q for the
                             three-month period ended September 30, 1998 and incorporated herein by
                             reference).

       5.1          --       Opinion of Thompson & Knight, A Professional Corporation.

       12.1         --       Statement re Computation of Ratio of Earnings to Fixed Charges.

       23.1         --       Consent of PricewaterhouseCoopers LLP.

       23.2         --       Consent of Thompson & Knight, A Professional Corporation (contained in its
                             opinion filed as Exhibit 5.1).

       24.1         --       Powers of Attorney (included on signature page).

       25.1         --       Form T-1 Statement of Eligibility and Qualification under the Trust Indenture 
                             Act of 1939, as amended, with respect to Trustee for Senior Debt Securities.

       25.2         --       Form T-1 Statement of Eligibility and Qualification under the Trust Indenture 
                             Act of 1939, as amended, with respect to Trustee for Subordinated Debt 
                             Securities.
</TABLE>

- --------------------------

       *        To be filed by amendment or by Form 8-K.

<PAGE>   1
[Form of December __, 1998]
                                                                     EXHIBIT 4.9

===============================================================================


                           NOBLE DRILLING CORPORATION
                                     ISSUER


                                       AND


                    CHASE BANK OF TEXAS, NATIONAL ASSOCIATION
                                     TRUSTEE


                                ----------------


                                    INDENTURE


                         DATED AS OF             , 199   
                                     ------------     ---


                                ----------------



                             SENIOR DEBT SECURITIES
                              (ISSUABLE IN SERIES)






===============================================================================


<PAGE>   2


                           NOBLE DRILLING CORPORATION

           RECONCILIATION AND TIE BETWEEN TRUST INDENTURE ACT OF 1939
                 AND INDENTURE, DATED AS OF              , 199   
                                            -------------     ---

<TABLE>
<CAPTION>
                                   Section of
                                Trust Indenture                                        Section(s) of
                                  Act of 1939                                            Indenture
                                ---------------                                         -------------

<S>                                                                                     <C>
(S) 310 (a)(1)............................................................................... 609
(a)(2)....................................................................................... 609
(a)(3)....................................................................................... Not Applicable
(a)(4)....................................................................................... Not Applicable
(b).......................................................................................... 608, 610
(S) 311 (a).................................................................................. 613
(b).......................................................................................... 613
(c).......................................................................................... Not Applicable
(S) 312 (a).................................................................................. 701, 702(a)
(b).......................................................................................... 702(b)
(c).......................................................................................... 702(b)
(S) 313 (a).................................................................................. 703(a)
(b).......................................................................................... 703(a)
(c).......................................................................................... 703(a)
(d).......................................................................................... 703(b)
(S) 314 (a).................................................................................. 704, 1005
(b).......................................................................................... Not Applicable
(c)(1)....................................................................................... 103
(c)(2)....................................................................................... 103
(c)(3)....................................................................................... Not Applicable
(d).......................................................................................... Not Applicable
(e).......................................................................................... 103
(S) 315 (a).................................................................................. 601(a)
(b).......................................................................................... 602
</TABLE>



<PAGE>   3

<TABLE>

<S>                                                                                           <C>
(c).......................................................................................... 601(b)
(d).......................................................................................... 601(c)
(d)(1)....................................................................................... 601(a)(1)
(d)(2)....................................................................................... 601(c)(2)
(d)(3)....................................................................................... 601(c)(3)
(e).......................................................................................... 514
(S) 316 (a)(1)(A)............................................................................ 502, 512
(a)(1)(B).................................................................................... 513
(a)(2)....................................................................................... Not Applicable
(a) last sentence............................................................................ 101
(b).......................................................................................... 508
(S) 317 (a)(1)............................................................................... 503
(a)(2)....................................................................................... 504
(b).......................................................................................... 1003
(S) 318 (a).................................................................................. 108
</TABLE>

- -------------
Note:    This reconciliation and tie shall not, for any purpose, be deemed to
         be a part of the Indenture.



<PAGE>   4


                               TABLE OF CONTENTS
<TABLE>


<S>      <C>                                                                                                      <C>
PARTIES...........................................................................................................1

RECITALS OF THE COMPANY...........................................................................................1

ARTICLE ONE -- DEFINITIONS AND OTHER PROVISIONS
               OF GENERAL APPLICATION

SECTION 101.  Definitions.........................................................................................1
         Act......................................................................................................2
         Additional Amounts.......................................................................................2
         Affiliate................................................................................................2
         Agent Members............................................................................................2
         Authenticating Agent.....................................................................................2
         Authorized Newspaper.....................................................................................2
         Board of Directors.......................................................................................2
         Board Resolution.........................................................................................3
         Business Day.............................................................................................3
         Commission...............................................................................................3
         Company..................................................................................................3
         Company Request..........................................................................................3
         Conversion Event.........................................................................................3
         Corporate Trust Office...................................................................................3
         Default..................................................................................................3
         Defaulted Interest.......................................................................................3
         Depositary...............................................................................................3
         Dollar...................................................................................................4
         Event of Default.........................................................................................4
         Exchange Rate............................................................................................4
         Holder...................................................................................................4
         Indenture................................................................................................4
         Interest.................................................................................................4
         Interest Payment Date....................................................................................4
         Judgment Currency........................................................................................4
         Maturity.................................................................................................4
         Officers' Certificate....................................................................................4
</TABLE>

- -----------------
Note:    This table of contents shall not, for any purpose, be deemed to be a
         part of the Indenture.


                                     - iv -

<PAGE>   5

<TABLE>

<S>               <C>                                                                                            <C>
         Opinion of Counsel.......................................................................................4
         Original Issue Discount Security.........................................................................4
         Outstanding..............................................................................................5
         Paying Agent.............................................................................................6
         Person...................................................................................................6
         Place of Payment.........................................................................................6
         Predecessor Security.....................................................................................6
         Redemption Date..........................................................................................6
         Redemption Price.........................................................................................6
         Regular Record Date......................................................................................6
         Required Currency........................................................................................6
         Responsible Officer......................................................................................6
         Securities...............................................................................................6
         Security Custodian.......................................................................................7
         Security Register........................................................................................7
         Special Record Date......................................................................................7
         Stated Maturity..........................................................................................7
         Subsidiary...............................................................................................7
         Trustee..................................................................................................7
         Trust Indenture Act......................................................................................7
         United States............................................................................................7
         United States Alien......................................................................................7
         U.S. Government Obligations..............................................................................7
         Vice President...........................................................................................8
         Wholly Owned Subsidiary..................................................................................8
         Yield to Maturity........................................................................................8

SECTION 102.      Incorporation by Reference of Trust Indenture Act...............................................8

SECTION 103.      Compliance Certificates and Opinions............................................................8

SECTION 104.      Form of Documents Delivered to Trustee..........................................................9

SECTION 105.      Acts of Holders; Record Dates..................................................................10

SECTION 106.      Notices, Etc., to Trustee and Company..........................................................11

SECTION 107.      Notice to Holders; Waiver......................................................................11

SECTION 108.      Conflict With Trust Indenture Act..............................................................12

SECTION 109.      Effect of Headings and Table of Contents.......................................................12

SECTION 110.      Successors and Assigns.........................................................................12

SECTION 111.      Separability Clause............................................................................12

SECTION 112.      Benefits of Indenture..........................................................................13

SECTION 113.      Governing Law..................................................................................13
</TABLE>


                                     - v -

<PAGE>   6


<TABLE>

<S>               <C>                                                                                            <C>
SECTION 114.      Legal Holidays.................................................................................13

SECTION 115.      Corporate Obligation...........................................................................13

ARTICLE TWO -- SECURITY FORMS

SECTION 201.      Forms Generally................................................................................13

SECTION 202.      Form of Trustee's Certificate of Authentication................................................14

SECTION 203.      Securities in Global Form......................................................................14

ARTICLE THREE -- THE SECURITIES

SECTION 301.      Amount Unlimited; Issuable in Series...........................................................17

SECTION 302.      Denominations..................................................................................20

SECTION 303.      Execution, Authentication, Delivery and Dating.................................................20

SECTION 304.      Temporary Securities...........................................................................22

SECTION 305.      Registration, Registration of Transfer and Exchange............................................22

SECTION 306.      Mutilated, Destroyed, Lost and Stolen Securities...............................................23

SECTION 307.      Payment of Interest; Interest Rights Preserved.................................................24

SECTION 308.      Persons Deemed Owners..........................................................................25

SECTION 309.      Cancellation...................................................................................26

SECTION 310.      Computation of Interest........................................................................26

SECTION 311.      CUSIP Numbers..................................................................................26

ARTICLE FOUR -- SATISFACTION AND DISCHARGE

SECTION 401.      Satisfaction and Discharge of Indenture........................................................26

SECTION 402.      Application of Trust Money.....................................................................28

SECTION 403.      Discharge of Liability on Securities of Any Series.............................................29

SECTION 404.      Reinstatement..................................................................................29

ARTICLE FIVE -- REMEDIES

SECTION 501.      Events of Default..............................................................................30

SECTION 502.      Acceleration of Maturity; Rescission and Annulment.............................................32
</TABLE>


                                     - vi -

<PAGE>   7



<TABLE>

<S>               <C>                                                                                            <C>
SECTION 503.      Collection of Indebtedness and Suits for Enforcement by
                  Trustee........................................................................................33

SECTION 504.      Trustee May File Proofs of Claim...............................................................34

SECTION 505.      Trustee May Enforce Claims Without Possession of Securities or
                  Coupons........................................................................................35

SECTION 506.      Application of Money Collected.................................................................35

SECTION 507.      Limitation on Suits............................................................................36

SECTION 508.      Unconditional Right of Holders to Receive Principal, Premium
                  and Interest...................................................................................36

SECTION 509.      Restoration of Rights and Remedies.............................................................37

SECTION 510.      Rights and Remedies Cumulative.................................................................37

SECTION 511.      Delay or Omission Not Waiver...................................................................37

SECTION 512.      Control by Holders.............................................................................37

SECTION 513.      Waiver of Past Defaults........................................................................38

SECTION 514.      Undertaking for Costs..........................................................................38

SECTION 515.      Waiver of Stay or Extension Laws...............................................................39

ARTICLE SIX -- THE TRUSTEE

SECTION 601.      Certain Duties and Responsibilities............................................................39

SECTION 602.      Notice of Defaults.............................................................................40

SECTION 603.      Certain Rights of Trustee......................................................................41

SECTION 604.      Not Responsible for Recitals or Issuance of Securities.........................................42

SECTION 605.      May Hold Securities............................................................................42

SECTION 606.      Money Held in Trust............................................................................42

SECTION 607.      Compensation and Reimbursement.................................................................42

SECTION 608.      Disqualification; Conflicting Interests........................................................43

SECTION 609.      Corporate Trustee Required; Eligibility........................................................44

SECTION 610.      Resignation and Removal; Appointment of Successor..............................................44
</TABLE>


                                    - vii -

<PAGE>   8


<TABLE>

<S>               <C>                                                                                           <C>
SECTION 611.      Acceptance of Appointment by Successor.........................................................46

SECTION 612.      Merger, Conversion, Consolidation or Succession to Business....................................47

SECTION 613.      Preferential Collection of Claims Against Company..............................................47

SECTION 614.      Appointment of Authenticating Agent............................................................47

ARTICLE SEVEN -- HOLDER'S LISTS AND REPORTS BY TRUSTEE AND COMPANY

SECTION 701.      Company to Furnish Trustee Names and Addresses of Holders......................................49

SECTION 702.      Preservation of Information; Communications to Holders.........................................49

SECTION 703.      Reports by Trustee.............................................................................50

SECTION 704.      Reports by Company.............................................................................50

ARTICLE EIGHT -- CONSOLIDATION, MERGER, CONVEYANCE, TRANSFER OR LEASE

SECTION 801.      Company May Consolidate, Etc., Only on Certain Terms...........................................50

SECTION 802.      Successor Person Substituted...................................................................51

ARTICLE NINE -- SUPPLEMENTAL INDENTURES

SECTION 901.      Supplemental Indentures Without Consent of Holders.............................................51

SECTION 902.      Supplemental Indentures With Consent of Holders................................................52

SECTION 903.      Execution of Supplemental Indentures...........................................................54

SECTION 904.      Effect of Supplemental Indentures..............................................................54

SECTION 905.      Conformity With Trust Indenture Act............................................................54

SECTION 906.      Reference in Securities to Supplemental Indentures.............................................54

ARTICLE TEN -- COVENANTS

SECTION 1001.     Payment of Principal, Premium and Interest.....................................................54

SECTION 1002.     Maintenance of Office or Agency................................................................55

SECTION 1003.     Money for Securities Payments to be Held in Trust..............................................55

SECTION 1004.     Existence......................................................................................56

SECTION 1005.     Statement by Officers as to Default............................................................57

SECTION 1006.     Waiver of Certain Covenants....................................................................57
</TABLE>


                                    - viii -

<PAGE>   9


<TABLE>

<S>               <C>                                                                                           <C>
SECTION 1007.     Additional Amounts.............................................................................57

ARTICLE ELEVEN -- REDEMPTION OF SECURITIES

SECTION 1101.     Applicability of Article.......................................................................58

SECTION 1102.     Election to Redeem; Notice to Trustee..........................................................58

SECTION 1103.     Selection by Trustee of Securities to be Redeemed..............................................59

SECTION 1104.     Notice of Redemption...........................................................................59

SECTION 1105.     Deposit of Redemption Price....................................................................60

SECTION 1106.     Securities Payable on Redemption Date..........................................................60

SECTION 1107.     Securities Redeemed in Part....................................................................60

ARTICLE TWELVE -- SINKING FUNDS

SECTION 1201.     Applicability of Article.......................................................................61

SECTION 1202.     Satisfaction of Sinking Fund Payments with Securities..........................................61

SECTION 1203.     Redemption of Securities for Sinking Fund......................................................62

ARTICLE THIRTEEN -- MEETINGS OF HOLDERS OF SECURITIES

SECTION 1301.     Purposes for Which Meetings May Be Called......................................................62

SECTION 1302.     Call, Notice and Place of Meetings.............................................................62

SECTION 1303.     Persons Entitled to Vote at Meetings...........................................................63

SECTION 1304.     Quorum; Action.................................................................................63

SECTION 1305.     Determination of Voting Rights; Conduct and Adjournment of
                  Meetings.......................................................................................64

SECTION 1306.     Counting Votes and Recording Action of Meetings................................................64

TESTIMONIUM......................................................................................................67

SIGNATURE AND SEALS..............................................................................................67
</TABLE>


                                     - ix -

<PAGE>   10


         INDENTURE, dated as of _______________, 199__, between NOBLE DRILLING
CORPORATION, a corporation duly organized and existing under the laws of the
State of Delaware (herein called the "Company"), having its principal office at
10370 Richmond Avenue, Suite 400, Houston, Texas 77042, and CHASE BANK OF
TEXAS, NATIONAL ASSOCIATION, a national banking association duly organized and
existing under the laws of the United States of America, as Trustee (herein
called the "Trustee"), the office of the Trustee at which at the date hereof
its corporate trust business is principally administered being 600 Travis,
Suite 1150, Houston, Texas 77002, Attention: Global Trust Service Department.

                            RECITALS OF THE COMPANY

         The Company has duly authorized the execution and delivery of this
Indenture to provide for the issuance from time to time of its unsecured
debentures, notes or other evidences of indebtedness (herein called the
"Securities"), to be issued in one or more series as provided in this
Indenture.

         This Indenture is subject to the provisions of the Trust Indenture Act
and the rules and regulations of the Commission promulgated thereunder that are
required to be part of this Indenture and, to the extent applicable, shall be
governed by such provisions.

         All things necessary to make this Indenture a valid agreement of the
Company, in accordance with its terms, have been done.

         NOW, THEREFORE, THIS INDENTURE WITNESSETH:

         For and in consideration of the premises and the purchase of the
Securities by the Holders thereof, it is mutually covenanted and agreed, for
the equal and proportionate benefit of all Holders of the Securities or of
series thereof, as follows:

                                  ARTICLE ONE

                        DEFINITIONS AND OTHER PROVISIONS
                             OF GENERAL APPLICATION

         SECTION 101. Definitions.

         For all purposes of this Indenture, except as otherwise expressly
provided or unless the context otherwise requires:

         (1)   the terms defined in this Article One have the meanings assigned
               to them in this Article One and include the plural as well as
               the singular;

         (2)   all accounting terms not otherwise defined herein have the
               meanings assigned to them in accordance with generally accepted
               accounting principles in the United States, and, except as
               otherwise herein expressly provided, the term "generally
               accepted accounting principles" with respect to any computation
               required or permitted hereunder shall mean such accounting
               principles as are generally accepted in the United States at the
               date of such computation; and

         (3)   the words "herein," "hereof" and "hereunder" and other words of
               similar import refer to this Indenture as a whole and not to any
               particular Article, Section or other subdivision.

         Certain terms, used principally in Article Six, are defined in Section
102.


                                     - 1 -

<PAGE>   11


         "Act," when used with respect to any Holder, has the meaning specified
in Section 105.

         "Additional Amounts" means any additional amounts that are required by
the express terms of a Security or by or pursuant to a Board Resolution, under
circumstances specified therein or pursuant thereto, to be paid by the Company
with respect to certain taxes, assessments or other governmental charges
imposed on certain Holders and that are owing to such Holders.

         "Affiliate" of any specified Person means any other Person directly or
indirectly controlling or controlled by or under direct or indirect common
control with such specified Person. For the purposes of this definition,
"control" when used with respect to any specified Person means the power to
direct the management and policies of such Person, directly or indirectly,
whether through the ownership of voting securities, by contract or otherwise;
and the terms "controlling" and "controlled" have meanings correlative to the
foregoing.

         "Agent Members" has the meaning specified in Section 203.

         "Authenticating Agent" means any Person, which may include the
Company, authorized by the Trustee to act on behalf of the Trustee pursuant to
Section 614 to authenticate Securities of one or more series.

         "Authorized Newspaper" means a newspaper, in the English language or
in an official language of the country of publication, customarily published on
each Business Day, whether or not published on Saturdays, Sundays or holidays,
and of general circulation in the place in connection with which the term is
used or in the financial community of such place. Where successive publications
are required to be made in Authorized Newspapers, the successive publications
may be made in the same or in different newspapers in the same city meeting the
foregoing requirements and in each case on any Business Day.

         "Board of Directors" means either the board of directors of the
Company or any duly authorized committee of that board.

         "Board Resolution" means a copy of a resolution certified by the
Secretary or an Assistant Secretary of the Company to have been duly adopted by
the Board of Directors and to be in full force and effect on the date of such
certification, and delivered to the Trustee.

         "Business Day," when used with respect to any Place of Payment, means
each Monday, Tuesday, Wednesday, Thursday and Friday that is not a day on which
banking institutions in that Place of Payment or the city in which the
Corporate Trust Office is located are authorized or obligated by law or
executive order to close.

         "Commission" means the Securities and Exchange Commission, as from
time to time constituted, created under the Securities Exchange Act of 1934, as
amended, or, if at any time after the execution of this instrument such
Commission is not existing and performing the duties now assigned to it under
the Trust Indenture Act, then the body performing such duties at such time.

         "Company" means the Person named as the "Company" in the first
paragraph of this instrument until a successor Person shall have become such
pursuant to the applicable provisions of this Indenture, and thereafter
"Company" shall mean such successor Person.

         "Company Request" and "Company Order" mean, respectively, a written
request or order signed in the name of the Company by its Chairman of the
Board, its President or a Vice President, and by its Treasurer, an Assistant
Treasurer, its Controller, an Assistant Controller, its Secretary or an
Assistant Secretary, and delivered to the Trustee.

         "Conversion Event" has the meaning specified in Section 501.


                                     - 2 -

<PAGE>   12


         "Corporate Trust Office" means the principal office of the Trustee in
Houston, Texas at which at any particular time its corporate trust business
shall be principally administered, which office at the date hereof is that
indicated in the introductory paragraph of this Indenture.

         "Default" means, with respect to the Securities of any series, any
event, act or condition that is, or after notice or the passage of time or both
would be, an Event of Default with respect to Securities of such series.

         "Defaulted Interest" has the meaning specified in Section 307.

         "Depositary" means, with respect to the Securities of any series
issuable or issued in whole or in part in a global form, the Person designated
as Depositary by the Company pursuant to Section 301 with respect to the
Securities of such series, until a successor Depositary shall have become such
pursuant to the applicable provisions of this Indenture, and thereafter
"Depositary" shall mean or include each Person who is then a Depositary
hereunder, and if at any time there is more than one such person, "Depositary"
as used with respect to the Securities of any series shall mean the Depositary
with respect to the Securities of that series.

         "Dollar" or "$" means a dollar or other equivalent unit in such coin
or currency of the United States as at the time shall be legal tender for the
payment of public and private debts.

         "Event of Default" has the meaning specified in Section 501.

         "Exchange Rate" has the meaning specified in Section 302.

         "Holder," when used with respect to any Security, means the Person in
whose name the Security is registered in the Security Register.

         "Indenture" means this instrument as originally executed or as it may
from time to time be supplemented or amended by one or more indentures
supplemental hereto entered into pursuant to the applicable provisions hereof
and shall include the terms of particular series of Securities established as
contemplated by Section 301 and the provisions of the Trust Indenture Act that
are deemed to be a part of and govern this instrument.

         "Interest," when used with respect to an Original Issue Discount
Security that by its terms bears interest only after Maturity, means interest
payable after Maturity.

         "Interest Payment Date," when used with respect to any Security, means
the Stated Maturity of an installment of interest on such Security.

         "Judgment Currency" has the meaning specified in Section 506.

         "Maturity," when used with respect to any Security, means the date on
which the principal of such Security or an installment of principal becomes due
and payable as therein or herein provided, whether at the Stated Maturity or by
declaration of acceleration, call for redemption or otherwise.

         "Officers' Certificate" means a certificate signed by the Chairman of
the Board, the President or a Vice President, and by the Treasurer, the
Controller, the Secretary or an Assistant Treasurer, Assistant Controller or
Assistant Secretary of the Company, and delivered to the Trustee, which
certificate shall be in compliance with Section 103 hereof.

         "Opinion of Counsel" means a written opinion of counsel, who may be
counsel for or an employee of the Company, rendered, if applicable, in
accordance with Section 314(c) of the Trust Indenture Act, which opinion shall
be in compliance with Section 103 hereof.


                                     - 3 -

<PAGE>   13


         "Original Issue Discount Security" means any Security that provides
for an amount less than the principal amount thereof to be due and payable upon
a declaration of acceleration of the Maturity thereof pursuant to Section 502.

         "Outstanding," when used with respect to Securities of a series, means
as of the date of determination, all Securities of such series theretofore
authenticated and delivered under this Indenture, except:

         (i)   Securities theretofore canceled by the Trustee or delivered to
               the Trustee for cancellation;

         (ii)  Securities for whose payment or redemption money in the
               necessary amount has been theretofore irrevocably deposited with
               the Trustee or any Paying Agent (other than the Company) in
               trust or set aside and segregated in trust by the Company (if
               the Company shall act as its own Paying Agent) for the Holders
               of such Securities; provided that, if such Securities are to be
               redeemed, notice of such redemption has been duly given pursuant
               to this Indenture or provision therefor satisfactory to the
               Trustee has been made; and

         (iii) Securities that have been paid pursuant to Section 306 or in
               exchange for or in lieu of which other Securities have been
               authenticated and delivered pursuant to this Indenture, other
               than any such Securities in respect of which there shall have
               been presented to the Trustee proof satisfactory to it that such
               Securities are held by a bona fide purchaser in whose hands such
               Securities are valid obligations of the Company; provided,
               however, that in determining whether the Holders of the
               requisite principal amount of the Outstanding Securities have
               given any request, demand, authorization, direction, notice,
               consent or waiver hereunder, or whether a quorum is present at a
               meeting of Holders of Securities, (a) the principal amount of an
               Original Issue Discount Security that shall be deemed to be
               Outstanding for such purposes shall be the principal amount
               thereof that would be due and payable as of the date of such
               determination upon acceleration of the Maturity thereof pursuant
               to Section 502, (b) the principal amount of a Security
               denominated in a foreign currency shall be the U.S. dollar
               equivalent, determined by the Company on the date of original
               issuance of such Security, of the principal amount (or, in the
               case of an Original Issue Discount Security, the U.S. dollar
               equivalent, determined on the date of original issuance of such
               Security, of the amount determined as provided in (a) above), of
               such Security and (c) Securities owned by the Company or any
               other obligor upon the Securities or any Affiliate of the
               Company or of such other obligor shall be disregarded and deemed
               not to be Outstanding, except that, in determining whether the
               Trustee shall be protected in relying upon any such request,
               demand, authorization, direction, notice, consent or waiver or
               upon any such determination as to the presence of a quorum, only
               Securities which a Responsible Officer of the Trustee knows to
               be so owned shall be so disregarded. Securities so owned which
               have been pledged in good faith may be regarded as Outstanding
               if the pledgee establishes to the satisfaction of the Trustee
               the pledgee's right so to act with respect to such Securities
               and that the pledgee is not the Company or any other obligor
               upon the Securities or any Affiliate of the Company or of such
               other obligor.

         "Paying Agent" means any Person, which may include the Company,
authorized by the Company to pay the principal of, premium (if any) or interest
on or any Additional Amounts with respect to any one or more series of
Securities on behalf of the Company.

         "Person" means any individual, corporation, partnership, limited
liability company, joint venture, incorporated or unincorporated association,
joint-stock company, trust, unincorporated organization or government or other
agency or political subdivision thereof or other entity of any kind.

         "Place of Payment," when used with respect to the Securities of any
series, means the place or places where the principal of, premium (if any) or
interest on or any Additional Amounts with respect to the Securities of such
series are payable as specified in accordance with Section 301 subject to the
provisions of Section 1002.


                                     - 4 -

<PAGE>   14


         "Predecessor Security" of any particular Security means every previous
Security evidencing all or a portion of the same debt as that evidenced by such
particular Security; and, for the purposes of this definition, any Security
authenticated and delivered under Section 306 in exchange for or in lieu of a
mutilated, destroyed, lost or stolen Security shall be deemed to evidence the
same debt as the mutilated, destroyed, lost or stolen Security.

         "Redemption Date," when used with respect to any Security to be
redeemed, means the date fixed for such redemption by or pursuant to the terms
of such Security and this Indenture.

         "Redemption Price," when used with respect to any Security to be
redeemed, means the price at which it is to be redeemed pursuant to the terms
of such Security and this Indenture.

         "Regular Record Date" for the interest payable on any Interest Payment
Date on the Securities of any series means the date specified for that purpose
as contemplated by Section 301, or, if not so specified, the last day of the
calendar month preceding such Interest Payment Date if such Interest Payment
Date is the fifteenth day of the calendar month or the fifteenth day of the
calendar month preceding such Interest Payment Date if such Interest Payment
Date is the first day of a calendar month, whether or not such day shall be a
Business Day.

         "Required Currency" has the meaning specified in Section 506.

         "Responsible Officer," when used with respect to the Trustee, means
any officer of the Trustee with direct responsibility for the administration of
this Indenture and also means, with respect to a particular corporate trust
matter, any other officer to whom such matter is referred because of his
knowledge of and familiarity with the particular subject.

         "Securities" has the meaning stated in the first recital of this
Indenture and more particularly means any Securities authenticated and
delivered under this Indenture.

         "Security Custodian" means, with respect to Securities of a series
issued in global form, the Trustee for Securities of such series, acting in its
capacity as custodian with respect to the Securities of such series, or any
successor entity thereto.

         "Security Register" and "Security Registrar" have the respective
meanings specified in Section 305.

         "Special Record Date" for the payment of any Defaulted Interest on the
Securities of any series means a date fixed by the Trustee pursuant to Section
307.

         "Stated Maturity," when used with respect to any Security or any
installment of principal thereof or interest thereon, means the date specified
in such Security as the fixed date on which the principal of such Security or
such installment of principal or interest is due and payable.

         "Subsidiary" means, as to any Person, a corporation more than 50% of
the outstanding voting stock of which is owned, directly or indirectly, by such
Person or by one or more other Subsidiaries of such Person, or by such Person
and one or more other Subsidiaries of such Person. For the purposes of this
definition, "voting stock" means stock that ordinarily has voting power for the
election of directors, whether at all times or only so long as no senior class
of stock has such voting power by reason of any contingency.

         "Trustee" means the Person named as the "Trustee" in the first
paragraph of this instrument until a successor Trustee shall have become such
pursuant to the applicable provisions of this Indenture, and thereafter
"Trustee" shall mean or include each Person who is then a Trustee hereunder,
and if at any time there is more than one such Person, "Trustee" as used with
respect to the Securities of any series shall mean the Trustee with respect to
Securities of that series.


                                     - 5 -

<PAGE>   15


         "Trust Indenture Act" means the Trust Indenture Act of 1939 as in
force at the date as of which this instrument was executed, except as provided
in Section 905; provided, however, that, in the event the Trust Indenture Act
of 1939 is amended after such date, "Trust Indenture Act" means, to the extent
required by any such amendment, the Trust Indenture Act of 1939 as so amended.

         "United States" means the United States of America (including the
States and the District of Columbia) and its "possessions," which include
Puerto Rico, the U.S. Virgin Islands, Guam, American Samoa, Wake Island and the
Northern Mariana Islands.

         "United States Alien" means any Person who, for United States federal
income tax purposes, is a foreign corporation, a nonresident alien individual,
a nonresident alien or foreign fiduciary of an estate or trust, or a foreign
partnership.

         "U.S. Government Obligations" has the meaning specified in Section
401.

         "Vice President," when used with respect to the Company or the
Trustee, means any vice president, whether or not designated by a number or a
word or words added before or after the title "vice president".

         "Wholly Owned Subsidiary" means, as to any Person, a corporation all
the outstanding voting stock (other than any directors' qualifying shares) of
which is owned, directly or indirectly, by such Person or by one or more other
Wholly Owned Subsidiaries of such Person, or by such Person and one or more
other Wholly Owned Subsidiaries of such Person. For the purposes of this
definition, "voting stock" means stock which ordinarily has voting power for
the election of directors, whether at all times or only so long as no senior
class of stock has such voting power by reason of any contingency.

         "Yield to Maturity," when used with respect to any Original Issue
Discount Security, means the yield to maturity, if any, set forth on the face
thereof.

         SECTION 102. Incorporation by Reference of Trust Indenture Act.

         Whenever this Indenture refers to a provision of the Trust Indenture
Act, the provision is incorporated by reference in and made a part of this
Indenture. The following Trust Indenture Act terms used in this Indenture have
the following meanings:

         "Bankruptcy Act" means the Bankruptcy Act or Title 11 of the United
States Code.

         "indenture securities" means the Securities.

         "indenture security holder" means a Holder.

         "indenture to be qualified" means this Indenture.

         "indenture trustee" or "institutional trustee" means the Trustee.

         "obligor" on the indenture securities means the Company or any other
obligor on the Securities.

         All terms used in this Indenture that are defined by the Trust
Indenture Act, defined by a Trust Indenture Act reference to another statute or
defined by Commission rule under the Trust Indenture Act and not otherwise
defined herein have the meanings assigned to them therein.


                                     - 6 -

<PAGE>   16


         SECTION 103. Compliance Certificates and Opinions.

         Except as otherwise expressly provided by this Indenture, upon any
application or request by the Company to the Trustee to take any action under
any provision of this Indenture, the Company shall furnish to the Trustee an
Officers' Certificate stating that all conditions precedent, if any, provided
for in this Indenture relating to the proposed action have been complied with
and an Opinion of Counsel stating that in the opinion of such counsel all such
conditions precedent, if any, have been complied with, except that in the case
of any such application or request as to which the furnishing of such documents
is specifically required by any provision of this Indenture relating to such
particular application or request, no additional certificate or opinion need be
furnished.

         Every certificate or opinion with respect to compliance with a
condition or covenant provided for in this Indenture shall include

         (1)   a statement that each Person signing such certificate or opinion
               has read such covenant or condition and the definitions herein
               relating thereto;

         (2)   a brief statement as to the nature and scope of the examination
               or investigation upon which the statements or opinions contained
               in such certificate or opinion are based;

         (3)   a statement that, in the opinion of each such Person, such
               Person has made such examination or investigation as is
               necessary to enable such Person to express an informed opinion
               as to whether or not such covenant or condition has been
               complied with; and

         (4)   a statement as to whether, in the opinion of each such Person,
               such condition or covenant has been complied with.

         SECTION 104. Form of Documents Delivered to Trustee.

         In any case where several matters are required to be certified by, or
covered by an opinion of, any specified Person, it is not necessary that all
such matters be certified by, or covered by the opinion of, only one such
Person, or that they be so certified or covered by only one document, but one
such Person may certify or give an opinion with respect to some matters and one
or more other such Persons as to other matters, and any such Person may certify
or give an opinion as to such matters in one or several documents.

         Any certificate or opinion of an officer of the Company may be based,
insofar as it relates to legal matters, upon a certificate or opinion of, or
representations by, counsel, unless such officer knows, or in the exercise of
reasonable care should know, that the certificate or opinion or representations
with respect to the matters upon which his certificate or opinion is based are
erroneous. Any such certificate or Opinion of Counsel may be based, insofar as
it relates to factual matters, upon a certificate or opinion of, or
representations by, an officer or officers of the Company stating that the
information with respect to such factual matters is in the possession of the
Company, unless such counsel knows, or in the exercise of reasonable care
should know, that the certificate or opinion or representations with respect to
such matters are erroneous.

         Where any Person is required to make, give or execute two or more
applications, requests, consents, certificates, statements, opinions or other
instruments under this Indenture, they may, but need not, be consolidated and
form one instrument.

         SECTION 105. Acts of Holders; Record Dates.

         (a) Any request, demand, authorization, direction, notice, consent,
waiver or other action provided by this Indenture to be given or taken by
Holders may be embodied in and evidenced by one or more instruments of
substantially similar tenor signed by such Holders in person or by an agent
duly appointed in writing. Except as herein otherwise expressly provided, such
action shall become effective when such instrument or instruments or record or
both


                                     - 7 -

<PAGE>   17


are delivered to the Trustee and, where it is hereby expressly required, to the
Company. Such instrument or instruments and any such record (and the action
embodied therein and evidenced thereby) are herein sometimes referred to as the
"Act" of the Holders signing such instrument or instruments and so voting at
any such meeting. Proof of execution of any such instrument or of a writing
appointing any such agent, or the holding of any Person of a Security, shall be
sufficient for any purpose of this Indenture and (subject to Section 601)
conclusive in favor of the Trustee and the Company, if made in the manner
provided in this Section 105. The record of any meeting of Holders of
Securities shall be proved in the manner provided in Section 1306.

         The Company may set a record date for purposes of determining the
identity of Holders of Securities entitled to vote or consent to any action by
vote or consent authorized or permitted under this Indenture. If a record date
is fixed, those Persons who were Holders of Outstanding Securities at such
record date (or their duly designated proxies), and only those Persons, shall
be entitled with respect to such Securities to take such action by vote or
consent or to revoke any vote or consent previously given, whether or not such
Persons continue to be Holders after such record date. Promptly after any
record date is set pursuant to this paragraph, the Company, at its own expense,
shall cause notice thereof to be given to the Trustee in writing in the manner
provided in Section 106 and to the relevant Holders as set forth in Section
107.

         (b) The fact and date of the execution by any Person of any such
instrument or writing may be proved by the affidavit of a witness of such
execution or by a certificate of a notary public or other officer authorized by
law to take acknowledgments of deeds, certifying that the individual signing
such instrument or writing acknowledged to him the execution thereof. Where
such execution is by a signer acting in a capacity other than his individual
capacity, such certificate or affidavit shall also constitute sufficient proof
of his authority. The fact and date of the execution of any such instrument or
writing, or the authority of the Person executing the same, may also be proved
in any other manner which the Trustee deems sufficient.

         (c) The principal amount and serial numbers of Securities held by any
Person, and the date of holding the same, shall be proved by the Security
Register.

         (d) In determining whether the Holders of the requisite principal
amount of Securities have given any request, demand, authorization, direction,
notice, consent or waiver under this Indenture, the principal amount of an
Original Issue Discount Security that may be counted in making such
determination and that shall be deemed to be Outstanding for such purposes
shall be equal to the amount of the principal thereof that would be due and
payable upon a declaration of acceleration of the Maturity thereof pursuant to
Section 502 at the time the taking of such action by the Holders of such
requisite principal amount is evidenced to the Trustee for such Securities.

         (e) Any request, demand, authorization, direction, notice, consent,
waiver or other Act of the Holder of any Security shall bind every future
Holder of the same Security and the Holder of every Security issued upon the
registration of transfer thereof or in exchange therefor or in lieu thereof in
respect of anything done, omitted or suffered to be done by the Trustee or the
Company in reliance thereon, whether or not notation of such action is made
upon such Security. Any consent or waiver of the Holder of any Security shall
be irrevocable for a period of six months after the date of execution thereof,
but otherwise any such Holder or subsequent Holder may revoke the request,
demand, authorization, direction, notice, consent or other Act as to his
Security or portion of his Security; provided, however, that such revocation
shall be effective only if the Trustee receives the notice of revocation before
the date the Act becomes effective.

         SECTION 106. Notices, Etc., to Trustee and Company.

         Any request, demand, authorization, direction, notice, consent, waiver
or Act of Holders or other document provided or permitted by this Indenture to
be made upon, given or furnished to, or filed with,

         (1)   the Trustee by any Holder or by the Company shall be sufficient
               for every purpose hereunder if made, given, furnished or filed
               in writing to or with the Trustee at its Corporate Trust Office,
               Attention: Global Trust Service Department, or


                                     - 8 -

<PAGE>   18


         (2)   the Company by the Trustee or by any Holder shall be sufficient
               for every purpose hereunder (unless otherwise herein expressly
               provided) if in writing and mailed, first-class postage prepaid,
               to the Company addressed to it at the address of its principal
               office specified in the first paragraph of this Indenture or at
               any other address previously furnished in writing to the Trustee
               by the Company, Attention: Corporate Secretary.

         SECTION 107. Notice to Holders; Waiver.

         Where this Indenture provides for notice to Holders of Securities of
any event, such notice shall be sufficiently given (unless otherwise herein
expressly provided) if in writing and mailed, first-class postage prepaid, to
each Holder affected by such event, at the address of such Holder as it appears
in the Security Register, not later than the latest date, and not earlier than
the earliest date, prescribed for the giving of such notice.

         In case by reason of the suspension of regular mail service, or by
reason of any other cause it shall be impracticable to give such notice to
Holders of Securities by mail, then such notification as shall be made with the
approval of the Trustee shall constitute a sufficient notification for every
purpose hereunder. In any case in which notice to Holders of Securities is
given by mail, neither the failure to mail such notice, nor any defect in any
notice so mailed, to any particular Holder of a Security, shall affect the
sufficiency of such notice with respect to other Holders of Securities.

         Where this Indenture provides for notice in any manner, such notice
may be waived in writing by the Person entitled to receive such notice, either
before or after the event, and such waiver shall be the equivalent of such
notice. Waivers of notice by Holders shall be filed with the Trustee, but such
filing shall not be a condition precedent to the validity of any action taken
in reliance upon such waiver.

         SECTION 108. Conflict With Trust Indenture Act.

         If any provision hereof limits, qualifies or conflicts with any
provision of the Trust Indenture Act or another provision hereof required to be
included in this Indenture by any of the provisions of the Trust Indenture Act,
such provision of the Trust Indenture Act shall control. If any provision of
this Indenture modifies or excludes any provision of the Trust Indenture Act
that may be so modified or excluded, the former provision shall be deemed to
apply to this Indenture as so modified or to be excluded.

         SECTION 109. Effect of Headings and Table of Contents.

         The Article and Section headings herein and the Table of Contents are
for convenience only and shall not affect the construction hereof.

         SECTION 110. Successors and Assigns.

         All covenants and agreements in this Indenture by the Company shall
bind its successors and assigns, whether or not so expressed.

         SECTION 111. Separability Clause.

         In case any provision in this Indenture or in the Securities shall be
invalid, illegal or unenforceable, the validity, legality and enforceability of
the remaining provisions shall not in any way be affected or impaired thereby.



                                     - 9 -

<PAGE>   19


         SECTION 112. Benefits of Indenture.

         Nothing in this Indenture or in the Securities, express or implied,
shall give to any Person any benefit or any legal or equitable right, remedy or
claim under this Indenture, other than the parties hereto and their successors
hereunder, any Authenticating Agent, Paying Agent or Security Registrar and the
Holders.

         SECTION 113. Governing Law.

         This Indenture and the Securities shall be governed by and construed
in accordance with the laws of the State of New York, but without giving effect
to applicable principles of conflicts of law to the extent the application of
the laws of another jurisdiction would be required thereby.

         SECTION 114. Legal Holidays.

         In any case where any Interest Payment Date, Redemption Date or Stated
Maturity of any Security shall not be a Business Day at any Place of Payment,
then (notwithstanding any other provision of this Indenture or of the
Securities) payment of principal of, premium (if any) and interest on or any
Additional Amounts with respect to Securities of any series need not be made at
such Place of Payment on such date, but may be made on the next succeeding
Business Day at such Place of Payment with the same force and effect as if made
on the Interest Payment Date or Redemption Date, or at the Stated Maturity,
provided that no interest shall accrue with respect to such payment for the
period from and after such Interest Payment Date, Redemption Date or Stated
Maturity, as the case may be.

         SECTION 115. Corporate Obligation.

         No recourse may be taken, directly or indirectly, against any
incorporator, subscriber to the capital stock, stockholder, officer, director
or employee of the Company or the Trustee or of any predecessor or successor of
the Company or the Trustee with respect to the Company's obligations on the
Securities or the obligations of the Company or the Trustee under this
Indenture or any certificate or other writing delivered in connection herewith.

                                  ARTICLE TWO

                                 SECURITY FORMS

         SECTION 201. Forms Generally.

         The Securities of each series shall be in fully registered form and in
substantially such form or forms (including temporary or permanent global form)
as shall be established by or pursuant to a Board Resolution or in one or more
indentures supplemental hereto, in each case with such appropriate insertions,
omissions, substitutions and other variations as are required or permitted by
this Indenture and may have such letters, numbers or other marks of
identification and such legends or endorsements placed thereon as may be
required to comply with the rules of any securities exchange or as may,
consistently herewith, be determined by the officers of the Company executing
such Securities, as evidenced by their execution of the Securities. If
temporary Securities of any series are issued in global form as permitted by
Section 304, the form thereof shall be established as provided in the preceding
sentence. A copy of the Board Resolution establishing the form or forms of
Securities of any series (or any such temporary global Security) shall be
delivered to the Trustee at or prior to the delivery of the Company Order
contemplated by Section 303 for the authentication and delivery of such
Securities (or any such temporary global Security).

         The definitive Securities shall be printed, lithographed or engraved
on steel engraved borders or may be produced in any other manner, all as
determined by the officers executing such Securities, as evidenced by their
execution thereof.



                                     - 10 -

<PAGE>   20


         SECTION 202. Form of Trustee's Certificate of Authentication.

         The Trustee's certificate of authentication shall be in substantially
the following form:

         "This is one of the Securities of the series designated therein
referred to in the within-mentioned Indenture.

                                  Chase Bank of Texas, National Association
                                  as Trustee

                                  By
                                    -------------------------------------------
                                       Authorized Signatory"


         SECTION 203. Securities in Global Form.

         If Securities of a series are issuable in global form, as contemplated
by Section 301, then, notwithstanding clause (10) of Section 301 and the
provisions of Section 302, any such Security shall represent such of the
Outstanding Securities of such series as shall be specified therein and may
provide that it shall represent the aggregate amount of Outstanding Securities
from time to time endorsed thereon and that the aggregate amount of Outstanding
Securities represented thereby may from time to time be reduced to reflect
exchanges or redemptions. Any endorsement of a Security in global form to
reflect the amount, or any increase or decrease in the amount, of Outstanding
Securities represented thereby shall be made by the Trustee in such manner and
upon instructions given by such Person or Persons as shall be specified in such
Security or in a Company Order to be delivered to the Trustee pursuant to
Section 303 or Section 304. Subject to the provisions of Section 303 and, if
applicable, Section 304, the Trustee shall deliver and redeliver any Security
in permanent global form in the manner and upon instructions given by the
Person or Persons specified in such Security or in the applicable Company
Order. With respect to the Securities of any series that are represented by a
Security in global form, the Company authorizes the execution and delivery by
the Trustee of a letter of representations or other similar agreement or
instrument in the form customarily provided for by the Depositary appointed
with respect to such global Security. Any Security in global form may be
deposited with the Depositary or its nominee, or may remain in the custody of
the Security Custodian therefor pursuant to an agreement between the Trustee
and the Depositary. If a Company Order pursuant to Section 303 or 304 has been,
or simultaneously is, delivered, any instructions by the Company with respect
to endorsement or delivery or redelivery of a Security in global form shall be
in writing but need not comply with Section 103 and need not be accompanied by
an Opinion of Counsel.

         Members of, or participants in, the Depositary ("Agent Members") shall
have no rights under this Indenture with respect to any Security issued in
global form held on their behalf by the Depositary, or the Security Custodian
as its custodian, or under such global Security, and the Depositary may be
treated by the Company, the Security Custodian and any agent of the Company or
the Trustee as the absolute owner of such global Security for all purposes
whatsoever. Notwithstanding the foregoing, (i) the registered holder of a
Security of any series issued in global form may grant proxies and otherwise
authorize any Person, including Agent Members and Persons that may hold
interests through Agent Members, to take any action that a Holder of such
series is entitled to take under this Indenture or the Securities of such
series and (ii) nothing herein shall prevent the Company, the Security
Custodian or any agent of the Company or the Security Custodian, from giving
effect to any written certification, proxy or other authorization furnished by
the Depositary or shall impair, as between the Depositary and its Agent
Members, the operation of customary practices governing the exercise of the
rights of a beneficial owner of any Security.

         Notwithstanding Section 305, except as otherwise specified as
contemplated by Section 301, any permanent global Security shall be
exchangeable only as provided in this paragraph. If the beneficial owners of
interests in a permanent global Security are entitled to exchange such interest
for Securities of such series and of like tenor and principal amount of another
authorized form and denomination, as specified as contemplated by Section 301,
then without unnecessary delay but in any event not later than the earliest
date on which such interests may be so exchanged, the Company shall deliver to
the Trustee definitive Securities of that series in an aggregate principal
amount equal to


                                     - 11 -

<PAGE>   21


the principal amount of such permanent global Security, executed by the
Company. On or after the earliest date on which such interests may be so
exchanged, such permanent global Security shall be surrendered from time to
time in accordance with instructions given to the Trustee and the Depositary
(which instructions shall be in writing but need not comply with Section 103 or
be accompanied by an Opinion of Counsel) by the Depositary or such other
depositary as shall be specified in the Company Order with respect thereto to
the Trustee, as the Company's agent for such purpose, to be exchanged, in whole
or in part, for definitive Securities of the same series without charge and the
Trustee shall authenticate and deliver, in exchange for each portion of such
permanent global Security, a like aggregate principal amount of other
definitive Securities of the same series of authorized denominations and of
like tenor as the portion of such permanent global Security to be exchanged;
provided, however, that no such exchanges may occur during a period beginning
at the opening of business 15 days before any selection of Securities of that
series is to be redeemed and ending on the relevant Redemption Date.

         Promptly following any such exchange in part, such permanent global
Security marked to evidence the partial exchange shall be returned by the
Trustee to the Depositary or such other depositary referred to above in
accordance with the instructions of the Company referred to above. If a
definitive Security is issued in exchange for any portion of a permanent global
Security after the close of business at the office or agency where such
exchange occurs on (i) any Regular Record Date and before the opening of
business at such office or agency on the relevant Interest Payment Date, or
(ii) any Special Record Date and before the opening of business at such office
or agency on the related proposed date for payment of Defaulted Interest,
interest or Defaulted Interest, as the case may be, will not be payable on such
Interest Payment Date or proposed date for payment, as the case may be, in
respect of such Security, but will be payable on such Interest Payment Date or
proposed for payment, as the case may be, only to the Person to whom interest
in respect of such portion of such permanent global Security is payable in
accordance with the provisions of this Indenture.

         Notwithstanding Section 305, except as otherwise specified as
contemplated by Section 301, transfers of a Security issued in global form
shall be limited to transfers of such global Security in whole, but not in
part, to the Depositary, its successors or their respective nominees. Interests
of beneficial owners in a Security issued in global form may be transferred in
accordance with the rules and procedures of the Depositary. Securities of any
series shall be transferred to all beneficial owners of a global Security of
such series in exchange for their beneficial interests in that global Security
if, and only if, either (1) the Depositary notifies the Company that it is
unwilling or unable to continue as Depositary for the global Security of such
series and a successor Depositary is not appointed by the Company within 90
days of such notice, (2) an Event of Default has occurred with respect to such
series and is continuing and the Security Registrar has received a request from
the Depositary or the Trustee to issue Securities of such series in lieu of all
or a portion of that global Security (in which case the Company shall deliver
Securities of such series within 30 days of such request) or (3) the Company
determines not to have the Securities of such series represented by a global
Security.

         In connection with any transfer of a portion of the beneficial
interest in a global Security of any series to beneficial owners pursuant to
this Section 203, the Security Registrar shall reflect on its books and records
the date and a decrease in the principal amount of the global Security of that
series in an amount equal to the principal amount of the beneficial interest in
the global Security of that series to be transferred, and the Company shall
execute, and the Trustee upon receipt of a Company Order for the authentication
and delivery of Securities of that series shall authenticate and deliver, one
or more Securities of the same series of like tenor and amount.

         In connection with the transfer of all the beneficial interests in a
global Security of any series to beneficial owners pursuant to this Section
203, the global Security shall be deemed to be surrendered to the Trustee for
cancellation, and the Company shall execute, and the Trustee shall authenticate
and deliver, to each beneficial owner identified by the Depositary in exchange
for its beneficial interest in the global Security, an equal aggregate
principal amount of Securities of that series of authorized denominations.

         Neither the Company nor the Trustee will have any responsibility or
liability for any aspect of the records relating to, or payments made on
account of, Securities of any series by the Depositary, or for maintaining,
supervising


                                     - 12 -

<PAGE>   22


or reviewing any records of the Depositary relating to such Securities. Neither
the Company nor the Trustee shall be liable for any delay by the related global
Security Holder or the Depositary in identifying the beneficial owners, and
each such Person may conclusively rely on, and shall be protected in relying
on, instructions from such global Security Holder or the Depositary for all
purposes (including with respect to the registration and delivery, and the
respective principal amounts, of the Securities to be issued).

         The provisions of the last sentence of Section 303 shall apply to any
Security in global form if such Security was never issued and sold by the
Company and the Company delivers to the Trustee the Security in global form
together with written instructions (which need not comply with Section 103 and
need not be accompanied by an Opinion of Counsel) with regard to the reduction
in the principal amount of Securities represented thereby, together with the
written statement contemplated by the last sentence of Section 303.

         Notwithstanding the provisions of Sections 201 and 307, unless
otherwise specified as contemplated by Section 301, payment of principal of,
premium (if any) and interest on or any Additional Amounts with respect to any
Security in permanent global form shall be made to the Person or Persons
specified therein.

         Notwithstanding the provisions of Section 308 and except as provided
in the preceding paragraph, the Company, the Trustee and any agent of the
Company or of the Trustee shall treat a Person as the Holder of such principal
amount of Outstanding Securities represented by a global Security as shall be
specified in a written statement, if any, of the Holder of such global Security
which is produced to the Security Registrar by such Holder.

         Global Securities may be issued in either temporary or permanent form.
Permanent global Securities will be issued in definitive form.

                                 ARTICLE THREE

                                 THE SECURITIES

         SECTION 301. Amount Unlimited; Issuable in Series.

         The aggregate principal amount of Securities that may be authenticated
and delivered under this Indenture is unlimited.

         The Securities may be issued in one or more series. There shall be
established in or pursuant to a Board Resolution, and set forth in an Officers'
Certificate, or established in one or more indentures supplemental hereto,
prior to the issuance of Securities of any series,

         (1)   the title of the Securities of such series (which shall
               distinguish the Securities of the series from all other
               Securities);

         (2)   any limit upon the aggregate principal amount of the Securities
               of such series which may be authenticated and delivered under
               this Indenture (except for Securities authenticated and
               delivered upon registration of transfer of, or in exchange for,
               or in lieu of, other Securities of such series pursuant to
               Section 203, 304, 305, 306, 906 or 1107);

         (3)   whether Securities of such series are to be issuable initially
               in temporary global form and whether any Securities of such
               series are to be issuable in permanent global form and, if so,
               whether beneficial owners of interests in any such global
               Security may exchange such interests for Securities of such
               series and of like tenor of any authorized form and denomination
               and the circumstances under which any such exchanges may occur,
               if other than in the manner provided in Sections 203 or 305, and
               the Depositary for any global Security or Securities of such
               series;


                                     - 13 -

<PAGE>   23


         (4)   the manner in which any interest payable on a temporary global
               Security of such series on any Interest Payment Date will be
               paid if other than in the manner provided in Section 304;

         (5)   the date or dates on which the principal or premium (if any) of
               the Securities of such series is payable or the method of
               determination thereof;

         (6)   the rate or rates, or the method of determination thereof, at
               which the Securities of such series shall bear interest, if any,
               whether and under what circumstances Additional Amounts with
               respect to such Securities shall be payable, the date or dates
               from which such interest shall accrue, the Interest Payment
               Dates on which such interest shall be payable and, if other than
               as set forth in Section 101, the Regular Record Date for the
               interest payable on any Securities on any Interest Payment Date;

         (7)   the place or places where, subject to the provisions of Section
               1002, the principal of, premium (if any) and interest on or any
               Additional Amounts with respect to the Securities of such series
               shall be payable;

         (8)   the period or periods within which, the price or prices (whether
               denominated in cash, securities or otherwise) at which and the
               terms and conditions upon which Securities of such series may be
               redeemed, in whole or in part, at the option of the Company, if
               the Company is to have that option, and the manner in which the
               Company must exercise any such option, if different from those
               set forth herein;

         (9)   the obligation, if any, of the Company to redeem or purchase
               Securities of such series pursuant to any sinking fund or
               analogous provisions or at the option of a Holder thereof and
               the period or periods within which, the price or prices (whether
               denominated in cash, securities or otherwise) at which and the
               terms and conditions upon which, Securities of such series shall
               be redeemed or purchased in whole or in part pursuant to such
               obligation;

         (10)  the denomination in which any Securities of that series shall be
               issuable, if other than denominations of $1,000 and any integral
               multiple thereof;

         (11)  the currency or currencies (including composite currencies), if
               other than Dollars, or the form, including equity securities,
               other debt securities (including Securities), warrants or any
               other securities or property of the Company or any other Person,
               in which payment of the principal of, premium (if any) and
               interest on or any Additional Amounts with respect to the
               Securities of such series shall be payable;

         (12)  if the principal of, premium (if any) or interest on or any
               Additional Amounts with respect to the Securities of such series
               are to be payable, at the election of the Company or a Holder
               thereof, in a currency or currencies (including composite
               currencies) other than that in which the Securities are stated
               to be payable, the currency or currencies (including composite
               currencies) in which payment of the principal of, premium (if
               any) and interest on or any Additional Amounts with respect to
               Securities of such series as to which such election is made
               shall be payable, and the periods within which and the terms and
               conditions upon which such election is to be made;

         (13)  if the amount of payments of principal of, premium (if any) and
               interest on or any Additional Amounts with respect to the
               Securities of such series may be determined with reference to
               any commodities, currencies or indices, values, rates or prices
               or any other index or formula, the manner in which such amounts
               shall be determined;

         (14)  if other than the entire principal amount thereof, the portion
               of the principal amount of Securities of


                                     - 14 -

<PAGE>   24


               such series that shall be payable upon declaration of
               acceleration of the Maturity thereof pursuant to Section 502;

         (15)  any additional means of satisfaction and discharge of this
               Indenture with respect to Securities of such series pursuant to
               Section 401, any additional conditions to discharge pursuant to
               Section 401 or 403 and the application, if any, of Section 403;

         (16)  any deletions or modifications of or additions to the
               definitions set forth in Section 101, Events of Default set
               forth in Section 501 or covenants of the Company set forth in
               Article Ten pertaining to the Securities of such series;

         (17)  if the Securities of such series are to be convertible into or
               exchangeable for equity securities, other debt securities
               (including Securities), warrants or any other securities or
               property of the Company or any other Person, at the option of
               the Company or the Holder or upon the occurrence of any
               condition or event, the terms and conditions for such conversion
               or exchange;

         (18)  whether any of such Securities will be subject to certain
               optional interest rate reset provisions;

         (19)  the additions or changes, if any, to the Indenture with respect
               to such Securities as shall be necessary to permit or facilitate
               the issuance of such Securities in bearer form, registered or
               not registrable as to principal, and with or without interest
               coupons; and

         (20)  any other terms of such series (which terms shall not be
               inconsistent with the provisions of this Indenture).

         All Securities of any one series shall be substantially identical
except as to denomination and except as may otherwise be provided in or
pursuant to the Board Resolution referred to above and (subject to Section 303)
set forth, or determined in the manner provided, in the Officers' Certificate
referred to above or in any such indenture supplemental hereto.

         At the option of the Company, interest on the Securities of any series
that bears interest may be paid by mailing a check to the address of any Holder
as such address shall appear in the Security Register.

         If any of the terms of the series are established by action taken
pursuant to a Board Resolution, a copy of an appropriate record of such action
together with such Board Resolution shall be certified by the Secretary or an
Assistant Secretary of the Company and delivered to the Trustee at or prior to
the delivery of the Officers' Certificate setting forth the terms of the
series.

         SECTION 302. Denominations.

         The Securities of each series shall be issuable in such denominations
as shall be specified as contemplated by Section 301. In the absence of any
such provisions with respect to the Securities of any series, the Securities of
such series denominated in Dollars shall be issuable in denominations of $1,000
and any integral multiple thereof. Unless otherwise provided as contemplated by
Section 301 with respect to any series of Securities, any Securities of a
series denominated in a currency other than Dollars shall be issuable in
denominations that are the equivalent, as determined by the Company by
reference to the noon buying rate in The City of New York for cable transfers
for such currency ("Exchange Rate"), as such rate is reported or otherwise made
available by the Federal Reserve Bank of New York, on the applicable issue date
for such Securities, of $1,000 and any integral multiple thereof.



                                     - 15 -

<PAGE>   25


         SECTION 303. Execution, Authentication, Delivery and Dating.

         The Securities shall be executed on behalf of the Company by its
Chairman of the Board, its President, its Treasurer or one of its Vice
Presidents, under its corporate seal reproduced thereon or affixed thereto
attested by its Secretary or one of its Assistant Secretaries. The signature of
any of these officers on the Securities may be manual or facsimile.

         Securities bearing the manual or facsimile signatures of individuals
who were at any time the proper officers of the Company shall bind the Company,
notwithstanding that such individuals or any of them have ceased to hold such
offices prior to the authentication and delivery of such Securities or did not
hold such offices at the date of such Securities.

         At any time and from time to time after the execution and delivery of
this Indenture, the Company may deliver Securities of any series executed by
the Company to the Trustee for authentication, together with a Company Order
for the authentication and delivery of such Securities, and the Trustee in
accordance with the Company Order shall authenticate and deliver such
Securities as in this Indenture provided and not otherwise.

         If the form or terms of the Securities of a series have been
established in or pursuant to one or more Board Resolutions or any other method
permitted by Sections 201 and 301, in authenticating such Securities, and
accepting the additional responsibilities under this Indenture in relation to
such Securities, the Trustee shall be entitled to receive, and (subject to
Section 601) shall be fully protected in relying upon, an Opinion of Counsel
stating that,

         (a)   if the form of such Securities has been established in
               conformity with the provisions of this Indenture;

         (b)   if the terms of such Securities have been established in
               conformity with the provisions of this Indenture; and

         (c)   that such Securities when authenticated and delivered by the
               Trustee and issued by the Company in the manner and subject to
               any conditions specified in such Opinion of Counsel, will
               constitute legal, valid and binding obligations of the Company,
               enforceable in accordance with their terms, except as such
               enforcement is subject to the effect of (i) bankruptcy,
               insolvency, fraudulent conveyance, reorganization or other laws
               relating to or affecting creditors' rights and (ii) general
               principles of equity (regardless of whether such enforcement is
               considered in a proceeding in equity or at law).

If such form or terms have been so established, the Trustee shall not be
required to authenticate such Securities if the issue of such Securities
pursuant to this Indenture will affect the Trustee's own rights, duties or
immunities under the Securities and this Indenture or otherwise in a manner not
reasonably acceptable to the Trustee.

         Each Security shall be dated the date of its authentication.

         No Security shall be entitled to any benefit under this Indenture or
be valid or obligatory for any purpose unless there appears on such Security a
certificate of authentication substantially in the form provided for herein
executed by the Trustee by manual signature, and such certificate upon any
Security shall be conclusive evidence, and the only evidence, that such
Security has been duly authenticated and delivered hereunder. Notwithstanding
the foregoing, if any Security shall have been authenticated and delivered
hereunder but never issued and sold by the Company, and the Company shall
deliver such Security to the Trustee for cancellation as provided in Section
309 together with a written statement (which need not comply with Section 103
and need not be accompanied by an Opinion of Counsel) stating that such
Security has never been issued and sold by the Company, for all purposes of
this Indenture such Security shall be deemed never to have been authenticated
and delivered hereunder and shall never be entitled to the benefits of this
Indenture.



                                     - 16 -

<PAGE>   26


         SECTION 304. Temporary Securities.

         Pending the preparation of definitive Securities of any series, the
Company may execute, and upon Company Order the Trustee shall authenticate and
deliver, temporary Securities that are printed, lithographed, typewritten,
mimeographed or otherwise produced, in any authorized denomination,
substantially of the tenor of the definitive Securities in lieu of which they
are issued, in registered form and with such appropriate insertions, omissions,
substitutions and other variations as the officers of the Company executing
such Securities may determine, as evidenced by their execution of such
Securities.

         Except in the case of temporary Securities in global form (which shall
be exchanged in accordance with the provisions of the following paragraphs), if
temporary Securities of any series are issued, the Company will cause
definitive Securities of that series to be prepared without unreasonable delay.
After the preparation of definitive Securities of such series, the temporary
Securities of such series shall be exchangeable for definitive Securities of
such series upon surrender of the temporary Securities of such series at the
office or agency of the Company in a Place of Payment for that series, without
charge to the Holder. Upon surrender for cancellation of any one or more
temporary Securities of any series, the Company shall execute and deliver a
Company Order requesting the Trustee to authenticate and deliver and the
Trustee shall authenticate and deliver in exchange therefor a like principal
amount of definitive Securities of the same series of authorized denominations.
Until so exchanged the temporary Securities of any series shall in all respects
be entitled to the same benefits under this Indenture as definitive Securities
of such series.

         All Outstanding temporary Securities of any series shall in all
respects be entitled to the same benefits under this Indenture as definitive
Securities of the same series and of like tenor authenticated and delivered
hereunder.

         SECTION 305. Registration, Registration of Transfer and Exchange.

         The Company shall cause to be kept for each series of Securities at
one of the offices or agencies maintained pursuant to Section 1002 a register
(the register maintained in such office and in any other office or agency of
the Company in a Place of Payment being herein sometimes collectively referred
to as the "Security Register") in which, subject to such reasonable regulations
as it may prescribe, the Company shall provide for the registration of
Securities and of transfers of Securities of such series. The Trustee is hereby
initially appointed "Security Registrar" for the purpose of registering
Securities and transfers of Securities as herein provided.

         Except as set forth in Section 203 or as may be provided pursuant to
Section 301, upon surrender for registration of transfer of any Security of any
series at the office or agency in a Place of Payment for that series, the
Company shall execute and deliver a Company Order requesting the Trustee to
authenticate and deliver and the Trustee shall authenticate and deliver, in the
name of the designated transferee or transferees, one or more new Securities of
the same series and of like tenor, of any authorized denominations and of a
like aggregate principal amount.

         At the option of the Holder, Securities of any series may be exchanged
for other Securities of the same series and of like tenor, of any authorized
denominations and of a like aggregate principal amount, upon surrender of the
Securities to be exchanged at such office or agency. Whenever any Securities
are so surrendered for exchange, the Company shall execute, and the Trustee
shall authenticate and deliver, the Securities which the Holder making the
exchange is entitled to receive.

         All Securities issued upon any registration of transfer or exchange of
Securities shall be the valid obligations of the Company, evidencing the same
debt, and entitled to the same benefits under this Indenture, as the Securities
surrendered upon such registration of transfer or exchange.

         Every Security presented or surrendered for registration of transfer
or for exchange shall (if so required by the Company or the Trustee) be duly
endorsed, or be accompanied by a written instrument of transfer in form
satisfactory to the Company and the Security Registrar duly executed, by the
Holder thereof or his attorney duly authorized in writing.


                                     - 17 -

<PAGE>   27


         No service charge shall be made for any registration of transfer or
exchange of Securities, but the Company may require payment of a sum sufficient
to cover any tax or other governmental charge that may be imposed in connection
with any registration of transfer or exchange of Securities, other than
exchange pursuant to Section 304, 906 or 1107 not involving any transfer.

         The Company shall not be required (i) to issue, register the transfer
of or exchange Securities of any series during a period beginning at the
opening of business 15 days before the day of the mailing of a notice of
redemption of Securities of such series selected for redemption and ending at
the close of business on the day of the mailing of the relevant notice of
redemption or (ii) to register the transfer of or exchange any Security so
selected for redemption in whole or in part, except the unredeemed portion of
any Security being redeemed in part.

         SECTION 306. Mutilated, Destroyed, Lost and Stolen Securities.

         If any mutilated Security is surrendered to the Trustee, the Company
shall execute and deliver a Company Order requesting the Trustee to
authenticate and deliver and the Trustee shall authenticate and deliver in
exchange therefor a new Security of the same series and of like tenor and
principal amount and bearing a number not contemporaneously outstanding.

         If there shall be delivered to the Company and the Trustee (i)
evidence to their satisfaction of the destruction, loss or theft of any
Security and (ii) such security or indemnity as may be required by them to save
each of them and any agent of either of them harmless, then, in the absence of
notice to the Company or the Trustee that such Security has been acquired by a
bona fide purchaser, the Company shall execute and upon the Company's request
the Trustee shall authenticate and deliver, in lieu of any such destroyed, lost
or stolen Security, a new Security of the same series and of like tenor and
principal amount and bearing a number not contemporaneously outstanding.

         In case any such mutilated, destroyed, lost or stolen Security has
become or is about to become due and payable, the Company in its discretion
may, instead of issuing a new Security, pay such Security.

         Upon the issuance of any new Security under this Section 306, the
Company may require the payment of a sum sufficient to cover any tax or other
governmental charge that may be imposed in relation thereto and any other
expenses (including the fee and expenses of the Trustee) connected therewith.

         Every new Security of any series issued pursuant to this Section 306
in lieu of any destroyed, lost or stolen Security shall constitute an original
additional contractual obligation of the Company, whether or not the destroyed,
lost or stolen Security shall be at any time enforceable by anyone, and shall
be entitled to all the benefits of this Indenture equally and proportionately
with any and all other Securities of that series duly issued hereunder.

         The provisions of this Section 306 are exclusive and shall preclude
(to the extent lawful) all other rights and remedies with respect to the
replacement or payment of mutilated, destroyed, lost or stolen Securities.

         SECTION 307. Payment of Interest; Interest Rights Preserved.

         Interest on any Security which is payable, and is punctually paid or
duly provided for, on any Interest Payment Date shall be paid to the Person in
whose name that Security (or one or more Predecessor Securities) is registered
at the close of business on the Regular Record Date for such interest. Unless
otherwise provided with respect to the Securities of any series, payment of
interest may be made at the option of the Company by check mailed or delivered
to the address of any Person entitled thereto as such address shall appear in
the Security Register.

         Any interest on any Security of any series which is payable, but is
not punctually paid or duly provided for,


                                     - 18 -

<PAGE>   28


on any Interest Payment Date (herein called "Defaulted Interest") shall
forthwith cease to be payable to the Holder on the relevant Regular Record Date
by virtue of having been such Holder, and such Defaulted Interest may be paid
by the Company, at its election in each case, as provided in clause (1) or (2)
below:

         (1)   The Company may elect to make payment of any Defaulted Interest
               to the Persons in whose names the Securities of such series (or
               their respective Predecessor Securities) are registered at the
               close of business on a Special Record Date for the payment of
               such Defaulted Interest, which shall be fixed in the following
               manner. The Company shall notify the Trustee in writing of the
               amount of Defaulted Interest proposed to be paid on each
               Security of such series and the date of the proposed payment,
               and at the same time the Company shall deposit with the Trustee
               an amount of money equal to the aggregate amount proposed to be
               paid in respect of such Defaulted Interest or shall make
               arrangements satisfactory to the Trustee for such deposit prior
               to the date of the proposed payment, such money when deposited
               to be held in trust for the benefit of the Persons entitled to
               such Defaulted Interest as in this clause (1) provided.
               Thereupon the Trustee shall fix a Special Record Date for the
               payment of such Defaulted Interest which shall be not more than
               15 days and not less than 10 days prior to the date of the
               proposed payment and not less than 10 days after the receipt by
               the Trustee of the notice of the proposed payment. The Trustee
               shall promptly notify the Company of such Special Record Date
               and, in the name and at the expense of the Company, shall cause
               notice of the proposed payment of such Defaulted Interest and
               the Special Record Date therefor to be mailed, first-class
               postage prepaid, to each Holder of Securities of such series at
               his address as it appears in the Security Register, not less
               than 10 days prior to such Special Record Date. The Trustee may,
               in its discretion, in the name and at the expense of the
               Company, cause a similar notice to be published at least once in
               an Authorized Newspaper, but such publication shall not be a
               condition precedent to the establishment of such Special Record
               Date. Notice of the proposed payment of such Defaulted Interest
               and the Special Record Date therefor having been so mailed, such
               Defaulted Interest shall be paid to the Persons in whose names
               the Securities of such series (or their respective Predecessor
               Securities) are registered at the close of business on such
               Special Record Date and shall no longer be payable pursuant to
               the following clause (2).

         (2)   The Company may make payment of any Defaulted Interest on the
               Securities of any series in any other lawful manner not
               inconsistent with the requirements of any securities exchange on
               which such Securities may be listed, and upon such notice as may
               be required by such exchange, if, after notice given by the
               Company to the Trustee of the proposed payment pursuant to this
               clause (2), such manner of payment shall be deemed practicable
               by the Trustee.

         Subject to the foregoing provisions of this Section 307, each Security
delivered under this Indenture, upon registration of transfer of, in exchange
for or in lieu of, any other Security, shall carry the rights to interest
accrued and unpaid, and to accrue, which were carried by such other Security.

         SECTION 308. Persons Deemed Owners.

         Prior to due presentment of a Security for registration of transfer,
the Company, the Trustee and any agent of the Company or the Trustee may treat
the Person in whose name such Security is registered as the owner of such
Security for the purpose of receiving payment of principal of, premium (if any)
and (subject to Sections 305 and 307) interest on such Security and for all
other purposes whatsoever, whether or not such Security be overdue, and neither
the Company, the Trustee nor any agent of the Company or the Trustee shall be
affected by notice to the contrary.

         SECTION 309. Cancellation.

         All Securities surrendered for payment, redemption, registration of
transfer or exchange or for credit against any sinking fund payment shall, if
surrendered to any Person other than the Trustee, be delivered to the Trustee.
All


                                     - 19 -

<PAGE>   29


Securities so delivered shall be promptly canceled by the Trustee. The Company
may at any time deliver to the Trustee for cancellation any Securities
previously authenticated and delivered hereunder which the Company may have
acquired in any manner whatsoever, and all Securities so delivered shall be
promptly canceled by the Trustee. No Securities shall be authenticated in lieu
of or in exchange for any Securities canceled as provided in this Section 309,
except as expressly permitted by this Indenture. All canceled Securities held
by the Trustee shall be disposed of by the Trustee in accordance with its
customary procedures, unless the Trustee is otherwise directed by a Company
Order.

         SECTION 310. Computation of Interest.

         Except as otherwise specified as contemplated by Section 301 for
Securities of any series, interest on the Securities of each series shall be
computed on the basis of a year compressing twelve 30-day months.

         SECTION 311. CUSIP Numbers.

         The Company in issuing the Securities may use "CUSIP" numbers (if then
generally in use), and, if so, the Trustee shall use "CUSIP" numbers in notices
of redemption as a convenience to Holders; provided that any such notice may
state that no representation is made as to the correctness of such numbers
either as printed on the Securities or as contained in any notice of a
redemption and that reliance may be placed only on the other identification
numbers printed on the Securities, and any such redemption shall not be
affected by any defect in or omission of such numbers.

                                  ARTICLE FOUR

                           SATISFACTION AND DISCHARGE

         SECTION 401. Satisfaction and Discharge of Indenture.

         This Indenture shall upon Company Request cease to be of further
effect with respect to Securities of a series, and the Trustee, at the expense
of the Company, shall execute proper instruments acknowledging satisfaction and
discharge of this Indenture with respect to Securities of such series, when

         (1) either

             (A)  all Securities of such series theretofore authenticated and
                  delivered (other than (i) Securities that have been
                  destroyed, lost or stolen and that have been replaced or paid
                  as provided in Section 306, and (ii) Securities for whose
                  payment money has theretofore been deposited in trust or
                  segregated and held in trust by the Company and thereafter
                  repaid to the Company or discharged from such trust, as
                  provided in Section 1003) have been delivered to the Trustee
                  for cancellation;

             (B)  with respect to all Outstanding Securities of such series not
                  theretofore delivered to the Trustee for cancellation, the
                  Company has deposited or caused to be deposited with the
                  Trustee as trust funds, under the terms of an irrevocable
                  trust agreement in form and substance satisfactory to the
                  Trustee, for the purpose money or U.S. Government Obligations
                  maturing as to principal and interest in such amounts and at
                  such times as will, together with the income to accrue
                  thereon, without consideration of any reinvestment thereof,
                  be sufficient to pay and discharge the entire indebtedness on
                  all Outstanding Securities of such series not theretofore
                  delivered to the Trustee for cancellation for principal of,
                  premium (if any) and interest on or any Additional Amounts
                  with respect to such Securities to the Stated Maturity or any
                  Redemption Date contemplated by the penultimate paragraph of
                  this Section 401, as the case may be; or



                                     - 20 -

<PAGE>   30


             (C)  the Company has properly fulfilled such other means of
                  satisfaction and discharge as is specified, as contemplated
                  by Section 301, to be applicable to the Securities of such
                  series;

         (2) the Company has paid or caused to be paid all other sums payable
             hereunder by the Company with respect to the Outstanding
             Securities of such series;

         (3) the Company has complied with any other conditions specified
             pursuant to Section 301 to be applicable to the discharge of
             Securities of such series pursuant to this Section 401;

         (4) the Company has delivered to the Trustee an Officers' Certificate
             and an Opinion of Counsel, each stating that all conditions
             precedent herein provided for relating to the satisfaction and
             discharge of this Indenture with respect to the Outstanding
             Securities of such series have been complied with;

         (5) if the conditions set forth in Section 401(1)(A) have not been
             satisfied, and unless otherwise specified pursuant to Section 301
             for the Securities of such series, the Company has delivered to
             the Trustee an Opinion of Counsel to the effect that the Holders
             of Securities of such series will not recognize income, gain or
             loss for United States federal income tax purposes as a result of
             such deposit, satisfaction and discharge and will be subject to
             United States federal income tax on the same amount and in the
             same manner and at the same time as would have been the case if
             such deposit, satisfaction and discharge had not occurred; and

         (6) no Default or Event of Default with respect to the Securities of
             such issue shall have occurred and be continuing on the date of
             such deposit or, in so far as clause (5) or (6) of Section 501 is
             concerned, at any time in the period ending on the 91st day after
             the date of such deposit (it being understood that this condition
             shall not be deemed satisfied until the expiration of such
             period).

         For the purposes of this Indenture, "U.S. Government Obligations"
means direct noncallable obligations of, or noncallable obligations the payment
of principal of and interest on which is guaranteed by, the United States of
America, or to the payment of which obligations or guarantees the full faith
and credit of the United States of America is pledged, or beneficial interests
in a trust the corpus of which consists exclusively of money or such
obligations or a combination thereof.

         If any Outstanding Securities of such series are to be redeemed prior
to their Stated Maturity, whether pursuant to any optional redemption
provisions or in accordance with any mandatory sinking fund requirement, the
trust agreement referred to in subclause (B) of clause (1) of this Section 401
shall provide therefor and the Company shall make such arrangements as are
satisfactory to the Trustee for the giving of notice of redemption by the
Trustee in the name, and at the expense, of the Company.

         Notwithstanding the satisfaction and discharge of this Indenture with
respect to the Outstanding Securities of such series pursuant to this Section
401, the obligations of the Company to the Trustee under Section 607, the
obligations of the Company to any Authenticating Agent under Section 614 and,
except for a discharge pursuant to subclause (A) of clause (1) of this Section
401, the obligations of the Company under Sections 305, 306, 404, 1001 and 1002
and the obligations of the Trustee under Section 402 and the last paragraph of
Section 1003 shall survive.

         SECTION 402. Application of Trust Money.

         Subject to the provisions of the last paragraph of Section 1003, all
money deposited with the Trustee pursuant to Section 401 shall be held in trust
and applied by it, in accordance with the provisions of the Securities and this
Indenture, to the payment, either directly or through any Paying Agent
(including the Company acting as its own Paying Agent) as the Trustee may
determine, to the Persons entitled thereto, of the principal of, premium (if
any) and interest on or any Additional Amounts with respect to Securities of
such Securities for the payment of which such money has been deposited with the
Trustee.


                                     - 21 -

<PAGE>   31


         SECTION 403. Discharge of Liability on Securities of Any Series.

         If this Section 403 is specified, as contemplated by Section 301, to
be applicable to Securities of any series, the Company shall be deemed to have
paid and discharged the entire indebtedness on all the Outstanding Securities
of such series, the obligation of the Company under this Indenture and the
Securities of such series to pay the principal of, premium (if any) and
interest on and any Additional Amounts with respect to Securities of such
series shall cease, terminate and be completely discharged, and the Trustee, at
the expense of the Company, shall execute proper instruments acknowledging such
satisfaction and discharge, when

         (1)   the Company has complied with the provisions of Section 401 of
               this Indenture (other than any additional conditions specified
               pursuant to Sections 301 and 401(3) and except that the Opinion
               of Counsel referred to in Section 401(5) shall state that it is
               based on a ruling by the Internal Revenue Service or other
               change since the date hereof under applicable Federal income tax
               law) with respect to all Outstanding Securities of such series,

         (2)   the Company has delivered to the Trustee a Company Request
               requesting such satisfaction and discharge,

         (3)   the Company has complied with any other conditions specified
               pursuant to Section 301 to be applicable to the discharge of
               Securities of such series pursuant to this Section 403, and

         (4)   the Company has delivered to the Trustee an Officers'
               Certificate and an Opinion of Counsel, each stating that all
               conditions precedent herein provided for relating to the
               discharge of the indebtedness on the Outstanding Securities of
               such series have been complied with.

         Upon the satisfaction of the conditions set forth in this Section 403
with respect to all the Outstanding Securities of any series, the terms and
conditions of such series, including the terms and conditions with respect
thereto set forth in this Indenture, shall no longer be binding upon, or
applicable to, the Company; provided that, the Company shall not be discharged
from any payment obligations in respect of Securities of such series which are
deemed not to be Outstanding under clause (iii) of the definition thereof if
such obligations continue to be valid obligations of the Company under
applicable law or pursuant to Section 305 or 306.

         SECTION 404. Reinstatement.

         If the Trustee or Paying Agent is unable to apply any money or U.S.
Government Obligations deposited with respect to Securities of any series in
accordance with Section 401 by reason of any legal proceeding or by reason of
any order or judgment of any court or governmental authority enjoining,
restraining or otherwise prohibiting such application, the Company's
obligations under this Indenture with respect to the Securities of such series
and the Securities of such series shall be revived and reinstated as though no
deposit had occurred pursuant to Section 401 until such time as the Trustee or
Paying Agent is permitted to apply all such money or U.S. Government
Obligations in accordance with Section 401; provided, however, that if the
Company has made any payment of principal of, premium (if any) or interest on
or any Additional Amounts with respect to any Securities because of the
reinstatement of its obligations, the Company shall be subrogated to the rights
of the Holders of such Securities to receive such payment from the money or
U.S. Government Obligations held by the Trustee or Paying Agent.



                                     - 22 -

<PAGE>   32


                                  ARTICLE FIVE

                                    REMEDIES

         SECTION 501. Events of Default.

         "Event of Default," wherever used herein with respect to Securities of
any series, means any one of the following events (whatever the reason for such
Event of Default and whether it shall be voluntary or involuntary or effected
by operation of law or pursuant to any judgment, decree or order of any court
or any order, rule or regulation of any administrative or governmental body),
unless it is either inapplicable to a particular series or it is specifically
deleted or modified in or pursuant to the supplemental indenture or Board
Resolution establishing such series of Securities or in the form of Security
for such series:

         (1)   default in the payment of any interest on or any Additional
               Amounts with respect to any Security of that series when such
               interest or Additional Amounts become due and payable, and
               continuance of such default for a period of 60 days; or

         (2)   default in the payment of the principal of or premium (if any)
               on any Security of that series at its Maturity; or

         (3)   default in the deposit of any mandatory sinking fund payment,
               when and as due by the terms of a Security of that series, and
               continuance of such default for a period of 60 days; or

         (4)   default in the performance or breach of any covenant of the
               Company in this Indenture (other than a covenant a default in
               whose performance or whose breach is elsewhere in this Section
               501 specifically dealt with or which has expressly been included
               in this Indenture solely for the benefit of one or more series
               of Securities other than that series), and continuance of such
               default or breach for a period of 90 days after there has been
               given, by registered or certified mail, to the Company by the
               Trustee or to the Company and the Trustee by the Holders of at
               least 25% in principal amount of all Outstanding Securities a
               written notice specifying such default or breach and requiring
               it to be remedied and stating that such notice is a "Notice of
               Default" hereunder; or

         (5)   the entry by a court having jurisdiction in the premises of (A)
               a decree or order for relief in respect of the Company in an
               involuntary case or proceeding under any applicable federal or
               state bankruptcy, insolvency, reorganization or other similar
               law or (B) a decree or order adjudging the Company a bankrupt or
               insolvent, or approving as properly filed a petition seeking
               reorganization, arrangement, adjustment or composition of or in
               respect of the Company under any applicable federal or state
               law, or appointing a custodian, receiver, liquidator, assignee,
               trustee, sequestrator or other similar official of the Company
               or of any substantial part of its property, or ordering the
               winding up or liquidation of its affairs, and the continuance of
               any such decree or order for relief or any such other decree or
               order unstayed and in effect for a period of 90 consecutive
               days; or

         (6)   the commencement by the Company of a voluntary case or
               proceeding under any applicable federal or state bankruptcy,
               insolvency, reorganization or other similar law or of any other
               case or proceeding to be adjudicated a bankrupt or insolvent, or
               the consent by it to the entry of a decree or order for relief
               in respect of the Company in an involuntary case or proceeding
               under any applicable federal or state bankruptcy, insolvency,
               reorganization or other similar law or to the commencement of
               any bankruptcy or insolvency case or proceeding against it, or
               the filing by it, of a petition or answer or consent seeking
               reorganization or relief under any applicable federal or state
               law, or the consent by it to the filing of such petition or to
               the appointment of or taking possession by a custodian,
               receiver, liquidator, assignee, trustee, sequestrator or similar
               official of the Company or of any substantial part


                                     - 23 -

<PAGE>   33


               of its property, or the making by it of an assignment for the
               benefit of creditors, or the admission by it in writing of its
               inability to pay its debts generally as they become due, or the
               taking of corporate action by the Company in furtherance of any
               such action; or

         (7)   any other Event of Default provided with respect to Securities
               of that series.

         Notwithstanding the foregoing provisions of this Section 501, if the
principal of, premium (if any) or any interest on or any Additional Amounts
with respect to any Security is payable in a currency or currencies (including
a composite currency) other than Dollars and such currency or currencies are
not available to the Company for making payment thereof due to the imposition
of exchange controls or other circumstances beyond the control of the Company
(a "Conversion Event"), the Company will be entitled to satisfy its obligations
to Holders of the Securities by making such payment in Dollars in an amount
equal to the Dollar equivalent of the amount payable in such other currency, as
determined by the Company by reference to the Exchange Rate, as such Exchange
Rate is certified for customs purposes by the Federal Reserve Bank of New York
on the date of such payment, or, if such rate is not then available, on the
basis of the most recently available Exchange Rate. Notwithstanding the
foregoing provisions of this Section 501, any payment made under such
circumstances in Dollars where the required payment is in a currency other than
Dollars will not constitute an Event of Default under this Indenture.

         Promptly after the occurrence of a Conversion Event with respect to
the Securities of any series, the Company shall give written notice thereof to
the Trustee; and the Trustee, promptly after receipt of such notice, shall give
notice thereof in the manner provided in Section 107 to the Holders of such
series. Promptly after the making of any payment in Dollars as a result of a
Conversion Event with respect to the Securities of any series, the Company
shall give notice in the manner provided in Section 107 to the Holders of such
series, setting forth the applicable Exchange Rate and describing the
calculation of such payments.

         SECTION 502. Acceleration of Maturity; Rescission and Annulment.

         If an Event of Default with respect to any Securities of any series at
the time Outstanding occurs and is continuing, then in every such case the
Trustee or the Holders of not less than 25% in principal amount of the
Outstanding Securities of (i) the series affected by such default (in the case
of an Event of Default described in clause (1), (2), (3) or (7) of Section 501)
or (ii) all series of Securities (in the case of an Event of Default described
in clause (4) of Section 501) may declare the principal amount (or, if any such
Securities are Original Issue Discount Securities, such portion of the
principal amount as may be specified in the terms of that series) of all of the
Securities of the series affected by such default or all series, as the case
may be, to be due and payable immediately, by a notice in writing to the
Company (and to the Trustee if given by Holders), and upon any such declaration
such amount shall become immediately due and payable. If an Event of Default
described in clause (5) or (6) of Section 501 shall occur, the principal amount
of the Outstanding Securities of all series ipso facto shall become and be
immediately due and payable without any declaration or other act on the part of
the Trustee or any Holder.

         At any time after such a declaration of acceleration with respect to
Securities of any series (or of all series, as the case may be) has been made
and before a judgment or decree for payment of the money due has been obtained
by the Trustee as hereinafter provided in this Article Five, the Holders of a
majority in principal amount of the Outstanding Securities of that series (or
of all series, as the case may be), by written notice to the Company and the
Trustee, may rescind and annul such declaration and its consequences if

         (1)      the Company has paid or deposited with the Trustee a sum
                  sufficient to pay

                  (A)  all overdue interest on, and any Additional Amounts with
                       respect to, all Securities of that series (or of all
                       series, as the case may be),

                  (B)  the principal of or premium (if any) on any Securities
                       of that series (or of all series, as the

                                    - 24 -

<PAGE>   34



                       case may be) which have become due otherwise than by
                       such declaration of acceleration and interest thereon at
                       the rate or rates prescribed therefor in such Securities
                       (in the case of Original Issue Discount Securities, the
                       Securities' Yield to Maturity),

                  (C)  to the extent that payment of such interest is lawful,
                       interest upon overdue interest and any Additional
                       Amounts at the rate or rates prescribed therefor in such
                       Securities (in the case of Original Issue Discount
                       Securities, the Securities' Yield to Maturity), and

                  (D)  all sums paid or advanced by the Trustee hereunder and
                       the reasonable compensation, expenses, disbursements and
                       advances of the Trustee, its agents and counsel and all
                       other amounts due the Trustee under Section 607; and

         (2)      all Events of Default with respect to Securities of that
                  series (or of all series, as the case may be), other than the
                  nonpayment of the principal of Securities of that series (or
                  of all series, as the case may be) which have become due
                  solely by such declaration of acceleration, have been cured
                  or waived as provided in Section 513.

No such rescission shall affect any subsequent default or impair any right
consequent thereon.

         SECTION 503. Collection of Indebtedness and Suits for Enforcement by
                      Trustee.

         The Company covenants that if

         (1)      default is made in the payment of any installment of interest
                  on, or any Additional Amounts with respect to, any Security
                  of any series when such interest or Additional Amounts shall
                  have become due and payable and such default continues for a
                  period of 60 days, or

         (2)      default is made in the payment of the principal of or premium
                  (if any) on any Security at the Maturity thereof, the Company
                  will, upon demand of the Trustee, pay to it, for the benefit
                  of the Holders of such Securities, the whole amount then due
                  and payable on such Securities for principal of, premium (if
                  any) and interest on or any Additional Amounts with respect
                  to such Securities and, to the extent that payment of such
                  interest shall be legally enforceable, interest on any
                  overdue principal, premium (if any) and on any overdue
                  interest or Additional Amounts, at the rate or rates
                  prescribed therefor in such Securities (or in the case of
                  Original Issue Discount Securities, the Securities' Yield to
                  Maturity), and, in addition thereto, such further amount as
                  shall be sufficient to cover the costs and expenses of
                  collection, including the reasonable compensation, expenses,
                  disbursements and advances of the Trustee, its agents and
                  counsel, and all other amounts due the Trustee under Section
                  607.

         If the Company fails to pay such amounts forthwith upon such demand,
the Trustee, in its own name and as trustee of an express trust, may institute
a judicial proceeding for the collection of the sums so due and unpaid, may
prosecute such proceeding to judgment or final decree and may enforce the same
against the Company or any other obligor upon such Securities and collect the
moneys adjudged or decreed to be payable in the manner provided by law out of
the property of the Company or any other obligor upon such Securities, wherever
situated.

         If an Event of Default with respect to Securities of any series occurs
and is continuing, the Trustee may in its discretion proceed to protect and
enforce its rights and the rights of the Holders of Securities of such series
by such appropriate judicial proceedings as the Trustee shall deem most
effectual to protect and enforce any such rights, whether for the specific
enforcement of any covenant or agreement in this Indenture or in aid of the
exercise of any power granted herein, or to enforce any other proper remedy.



                                     - 25 -

<PAGE>   35


         SECTION 504. Trustee May File Proofs of Claim.

         In case of the pendency of any receivership, insolvency, liquidation,
bankruptcy, reorganization, arrangement, adjustment, composition or other
judicial proceeding relative to the Company or any other obligor upon the
Securities or the property of the Company or of such other obligor or their
creditors, the Trustee (irrespective of whether the principal (or lesser amount
in the case of Original Issue Discount Securities) of the Securities shall then
be due and payable as therein expressed or by declaration or otherwise and
irrespective of whether the Trustee shall have made any demand on the Company
for the payment of overdue principal of, premium (if any), interest on or any
Additional Amounts with respect to such Securities) shall be entitled and
empowered, by intervention in such proceeding or otherwise,

         (i)   to file and prove a claim for the whole amount of principal (or
               lesser amount in the case of Original Issue Discount Securities)
               (and premium, if any) and interest and any Additional Amounts
               owing and unpaid in respect of the Securities and to file such
               other papers or documents as may be necessary or advisable to
               have the claims of the Trustee (including any claim for the
               reasonable compensation, expenses, disbursements and advances of
               the Trustee, its agents and counsel) and of the Holders allowed
               in such judicial proceeding, and

         (ii)  to collect and receive any monies or other property payable or
               deliverable on any such claims and to distribute the same; and
               any custodian, receiver, assignee, trustee, liquidator,
               sequestrator or other similar official in any such judicial
               proceeding is hereby authorized by each Holder to make such
               payments to the Trustee and, in the event that the Trustee shall
               consent to the making of such payments directly to the Holders,
               to pay to the Trustee any amount due it for the reasonable
               compensation, expenses, disbursements and advances of the
               Trustee, its agents and counsel, and any other amounts due the
               Trustee under Section 607.

         Nothing herein contained shall be deemed to authorize the Trustee to
authorize or consent to or accept or adopt on behalf of any Holder any plan of
reorganization, arrangement, adjustment or composition affecting the Securities
or the rights of any Holder thereof or to authorize the Trustee to vote in
respect of the claim of any Holder in any such proceedings; provided, however,
that the Trustee may, on behalf of the Holders, vote for the election of a
trustee in bankruptcy or similar official.

         SECTION 505. Trustee May Enforce Claims Without Possession of
                      Securities or Coupons.

         All rights of action and claim under this Indenture or the Securities
may be prosecuted and enforced by the Trustee without possession of any of the
Securities or the production thereof in any proceeding relating thereto; any
such proceeding instituted by the Trustee shall be brought in its own name as
trustee of an express trust; after provision for the payment of the reasonable
compensation, expenses, disbursements and advances of the Trustee, its agents
and counsel, and any other amounts due the Trustee under Section 607, any
recovery of judgment shall be for the ratable benefit of the Holders of the
Securities in respect of which such judgment has been recovered.

         SECTION 506. Application of Money Collected.

         Any money collected by the Trustee pursuant to this Article Five shall
be applied in the following order, at the date or dates fixed by the Trustee
and, in case of the distribution of such money on account of principal of,
premium (if any) or interest on or any Additional Amounts with respect to any
Securities, upon presentation of the Securities, and the notation thereon of
the payment if only partially paid and upon surrender thereof if fully paid:

         FIRST: To the payment of all amounts due the Trustee under Section
607;

         SECOND: To the payment of the amounts then due and unpaid for
principal of, premium (if any) and interest


                                     - 26 -

<PAGE>   36


on and any Additional Amounts with respect to such Securities in respect of
which or for the benefit of which such money has been collected, ratably,
without preference or priority of any kind, according to the amounts due and
payable on such Securities for principal of, premium (if any), interest on and
Additional Amounts, respectively; and

         THIRD: The balance, if any, to the Company.

         To the fullest extent allowed under applicable law, if for the purpose
of obtaining judgment against the Company in any court it is necessary to
convert the sum due in respect of the principal of, premium (if any) or
interest on or any Additional Amounts with respect to the Securities of any
series (the "Required Currency") into a currency in which a judgment will be
rendered (the "Judgment Currency"), the rate of exchange used shall be the rate
at which in accordance with normal banking procedures the Trustee could
purchase in The City of New York the Required Currency with the Judgment
Currency on the New York Business Day next preceding that on which final
judgment is given. Neither the Company nor the Trustee shall be liable for any
shortfall nor shall it benefit from any windfall in payments to Holders of
Securities under this Section 506 caused by a change in exchange rates between
the time the amount of a judgment against it is calculated as above and the
time the Trustee converts the Judgment Currency into the Required Currency to
make payments under this Section 506 to Holders of Securities, but payment of
such judgment shall discharge all amounts owed by the Company on the claim or
claims underlying such judgment.

         SECTION 507. Limitation on Suits.

         Subject to Section 508, no Holder of any Security of any series shall
have any right to institute any proceeding, judicial or otherwise, with respect
to this Indenture, or for the appointment of a receiver or trustee, or for any
other remedy hereunder, unless

         (1)   an Event of Default with respect to Securities of such series
               shall have occurred and be continuing and such Holder has
               previously given written notice to the Trustee of such
               continuing Event of Default;

         (2)   the Holders of not less than 25% in principal amount of the
               Outstanding Securities of that series shall have made written
               request to the Trustee to institute proceedings in respect of
               such Event of Default in its own name as Trustee hereunder;

         (3)   such Holder or Holders have offered to the Trustee reasonable
               indemnity against the costs, expenses and liabilities to be
               incurred in compliance with such request;

         (4)   the Trustee for 60 days after its receipt of such notice,
               request and offer of indemnity has failed to institute any such
               proceeding; and

         (5)   no direction inconsistent with such written request has been
               given to the Trustee during such 60-day period by the Holders of
               a majority in principal amount of the Outstanding Securities of
               that series; it being understood and intended that no one or
               more of such Holders shall have any right in any manner whatever
               by virtue of, or by availing of, any provision of this Indenture
               to affect, disturb or prejudice the rights of any other of such
               Holders, or to obtain or to seek to obtain priority or
               preference over any other of such Holders or to enforce any
               right under this Indenture, except in the manner herein provided
               and for the equal and ratable benefit of all of such Holders.

         SECTION 508. Unconditional Right of Holders to Receive Principal,
Premium and Interest.

         Notwithstanding any other provision in this Indenture, the Holder of
any Security shall have the right, which is absolute and unconditional, to
receive payment of the principal of, premium (if any) and (subject to Section
307) interest on or any Additional Amounts with respect to such Security on the
Stated Maturity or Maturities expressed in


                                     - 27 -

<PAGE>   37


such Security (or, in the case of redemption, on the Redemption Date) and to
institute suit for the enforcement of any such payment on or after such
respective dates, and such rights shall not be impaired or affected without the
consent of such Holder.

         SECTION 509. Restoration of Rights and Remedies.

         If the Trustee or any Holder of any Security has instituted any
proceeding to enforce any right or remedy under this Indenture and such
proceeding has been discontinued or abandoned for any reason, or has been
determined adversely to the Trustee or to such Holder, then and in every such
case, the Company, the Trustee and the Holders shall, subject to any
determination in such proceeding, be restored severally and respectively to
their former positions hereunder, and thereafter all rights and remedies of the
Trustee and the Holders shall continue as though no such proceeding had been
instituted.

         SECTION 510. Rights and Remedies Cumulative.

         Except as otherwise provided with respect to the replacement or
payment of mutilated, destroyed, lost or stolen Securities in the last
paragraph of Section 306, no right or remedy herein conferred upon or reserved
to the Trustee or to the Holders is intended to be exclusive of any other right
or remedy, and every right and remedy shall, to the extent permitted by law, be
cumulative and in addition to every other right and remedy given hereunder or
now or hereafter existing at law or in equity or otherwise. The assertion or
employment of any right or remedy hereunder, or otherwise, shall not prevent
the concurrent assertion or employment of any other appropriate right or
remedy.

         SECTION 511. Delay or Omission Not Waiver.

         No delay or omission of the Trustee or of any Holder of any Securities
to exercise any right or remedy accruing upon any Event of Default shall impair
any such right or remedy or constitute a waiver of any such Event of Default or
an acquiescence therein. Every right and remedy given by this Article Five or
by law to the Trustee or to the Holders may be exercised from time to time, and
as often as may be deemed expedient, by the Trustee or by the Holders, as the
case may be.

         SECTION 512. Control by Holders.

         With respect to Securities of any series, the Holders of a majority in
principal amount of the Outstanding Securities of such series shall have the
right to direct the time, method and place of conducting any proceeding for any
remedy available to the Trustee, or exercising any trust or power conferred on
the Trustee, relating to or arising under an Event of Default described in
clause (1), (2), (3) or (7) of Section 501, and with respect to all Securities
the Holders of a majority in principal amount of all Outstanding Securities
shall have the right to direct the time, method and place of conducting any
remedy available to the Trustee, or exercising any trust or power conferred on
the Trustee, not relating to or arising under such an Event of Default,
provided that in each such case

         (1)   the Trustee shall have the right to decline to follow any such
               direction if the Trustee, being advised by counsel, determines
               that the action so directed may not lawfully be taken or would
               conflict with this Indenture or if the Trustee in good faith
               shall, by a Responsible Officer, determine that the proceedings
               so directed would involve it in personal liability or be
               unjustly prejudicial to the Holders not taking part in such
               direction, and

         (2)   the Trustee may take any other action deemed proper by the
               Trustee which is not inconsistent with such direction.



                                     - 28 -

<PAGE>   38


         SECTION 513. Waiver of Past Defaults.

         Subject to Sections 508 and 902, the Holders of a majority in
principal amount of the Outstanding Securities of any series may on behalf of
the Holders of all the Securities of such series waive any past default
hereunder with respect to such series and its consequences, and the Holders of
a majority in principal amount of all Outstanding Securities may on behalf of
the Holders of all Securities waive any other past default hereunder and its
consequences, except in each case a default

         (1)   in the payment of the principal of, premium (if any) or interest
               on or any Additional Amounts with respect to any Security, or

         (2)   in respect of a covenant or provision hereof that under Article
               Nine cannot be modified or amended without the consent of the
               Holder of each Outstanding Security affected.

         Upon any such waiver, such default shall cease to exist, and any Event
of Default arising therefrom shall be deemed to have been cured, for every
purpose of this Indenture; but no such waiver shall extend to any subsequent or
other default or impair any right consequent thereon.

         SECTION 514. Undertaking for Costs.

         All parties to this Indenture agree, and each Holder of any Security
by his acceptance thereof shall be deemed to have agreed, that any court may in
its discretion require, in any suit for the enforcement of any right or remedy
under this Indenture, or in any suit against the Trustee for any action taken
or omitted by it as Trustee, the filing by any party litigant in such suit of
an undertaking to pay the costs of such suit, and that such court may in its
discretion assess reasonable costs, including reasonable attorneys' fees,
against any party litigant in such suit, having due regard to the merits and
good faith of the claims or defenses made by such party litigant. The
provisions of this Section 514 shall not apply to any suit instituted by the
Company, by the Trustee, by any Holder or group of Holders holding in the
aggregate more than 10% in principal amount of the Outstanding Securities of
any series, or by any Holder for the enforcement of the payment of the
principal of, premium (if any) or interest on or any Additional Amounts with
respect to any Security on or after the Stated Maturity or Maturities expressed
in such Security (or, in the case of redemption, on or after the Redemption
Date).

         SECTION 515. Waiver of Stay or Extension Laws.

         The Company covenants (to the extent that it may lawfully do so) that
it will not at any time insist upon, or plead, or in any manner whatsoever
claim or take the benefit or advantage of, any stay or extension law wherever
enacted, now or at any time hereafter in force, which may affect the covenants
or the performance of this Indenture; and the Company (to the extent that it
may lawfully do so) hereby expressly waives all benefit or advantage of any
such law and covenants that it will not hinder, delay or impede the execution
of any power herein granted to the Trustee, but will suffer and permit the
execution of every such power as though no such law had been enacted.

                                  ARTICLE SIX

                                  THE TRUSTEE

         SECTION 601. Certain Duties and Responsibilities.

         (a)   Except during the continuance of an Event of Default with
               respect to the Securities of any series,

               (1) the Trustee undertakes to perform such duties and only such
                   duties as are specifically set forth in this Indenture, and
                   no implied covenants or obligations shall be read into this
                   Indenture against the Trustee; and

                                     - 29 -

<PAGE>   39


               (2) in the absence of bad faith on its part, the Trustee may
                   conclusively rely, as to the truth of the statements and the
                   correctness of the opinions expressed therein, upon
                   certificates or opinions furnished to the Trustee and
                   conforming to the requirements of this Indenture; but in the
                   case of any such certificates or opinions that by any
                   provision hereof are specifically required to be furnished
                   to the Trustee, the Trustee shall be under a duty to examine
                   the same to determine whether or not they conform to the
                   requirements of this Indenture.

         (b)   In case an Event of Default has occurred and is continuing with
               respect to the Securities of any series, the Trustee shall
               exercise such of the rights and powers vested in it by this
               Indenture, and use the same degree of care and skill in their
               exercise, as a prudent man would exercise or use under the
               circumstances in the conduct of his own affairs.

         (c)   No provision of this Indenture shall be construed to relieve the
               Trustee from liability for its own negligent action, its own
               negligent failure to act or its own willful misconduct, except
               that

               (1) this clause (1) shall not be construed to limit the effect
                   of subsection (a) of this Section 601;

               (2) the Trustee shall not be liable for any error of judgment
                   made in good faith by a Responsible Officer, unless it shall
                   be proved that the Trustee was negligent in ascertaining the
                   pertinent facts;

               (3) the Trustee shall not be liable with respect to any action
                   it takes or omits to take in good faith in accordance with
                   the direction of the Holders of a majority in principal
                   amount of the Outstanding Securities of any series or of all
                   series, determined as provided in Section 512, relating to
                   the time, method and place of conducting any proceeding for
                   any remedy available to the Trustee, or exercising any trust
                   or power conferred upon the Trustee, under this Indenture
                   with respect to the Securities of such series; and

               (4) no provision of this Indenture shall require the Trustee to
                   expend or risk its own funds or otherwise incur any
                   financial liability in the performance of any of its duties
                   hereunder, or in the exercise of any of its rights or
                   powers, if it shall have reasonable grounds for believing
                   that repayment of such funds or adequate indemnity against
                   such risk or liability is not reasonably assured to it.

         (d)   Whether or not therein expressly so provided, every provision
               of this Indenture relating to the conduct or affecting the
               liability of or affording protection to the Trustee shall be
               subject to the provisions of this Section 601.

         SECTION 602. Notice of Defaults.

         Within 90 days after the occurrence of any Default or Event of Default
with respect to the Securities of any series, the Trustee shall give notice of
such Default or Event of Default known to the Trustee to all Holders of
Securities of such series in the manner provided in Section 107, unless such
default shall have been cured or waived; provided, however, that, except in the
case of a Default or Event of Default in the payment of the principal of,
premium (if any) or interest on or any Additional Amounts with respect to any
Security of such series or in the payment of any sinking fund installment with
respect to Securities of such series, the Trustee shall be protected in
withholding such notice if and so long as the board of directors, the executive
committee or a trust committee of directors or Responsible Officers of the
Trustee in good faith determine that the withholding of such notice is in the
interest of the Holders of Securities of such series; and provided, further,
that in the case of any Default or Event of Default of the character specified
in


                                     - 30 -

<PAGE>   40


Section 501(4) with respect to Securities of such series, no such notice to
Holders shall be given until at least 60 days after the occurrence thereof.

         SECTION 603. Certain Rights of Trustee.

         Subject to the provisions of Section 601:

         (a)   the Trustee may rely and shall be protected in acting or
               refraining from acting upon any resolution, certificate,
               statement, instrument, opinion, report, notice, request,
               direction, consent, order, bond, debenture, note, coupon, other
               evidence of indebtedness or other paper or document believed by
               it to be genuine and to have been signed or presented by the
               proper party or parties;

         (b)   any request or direction of the Company mentioned herein shall
               be sufficiently evidenced by a Company Request or Company Order
               and any resolution of the Board of Directors may be sufficiently
               evidenced by a Board Resolution;

         (c)   whenever in the administration of this Indenture the Trustee
               shall deem it desirable that a matter be proved or established
               prior to taking, suffering or omitting any action hereunder, the
               Trustee (unless other evidence be herein specifically
               prescribed) may, in the absence of bad faith on its part, rely
               upon an Officers' Certificate;

         (d)   the Trustee may consult with counsel and the written advice of
               such counsel or any Opinion of Counsel shall be full and
               complete authorization and protection in respect of any action
               taken, suffered or omitted by it hereunder in good faith and in
               reliance thereon;

         (e)   the Trustee shall be under no obligation to exercise any of the
               rights or powers vested in it by this Indenture at the request
               or direction of any of the Holders pursuant to this Indenture,
               unless such Holders shall have offered to the Trustee reasonable
               security or indemnity against the costs, expenses and
               liabilities that might be incurred by it in compliance with such
               request or direction;

         (f)   the Trustee shall not be bound to make any investigation into
               the facts or matters stated in any resolution, certificate,
               statement, instrument, opinion, report, notice, request,
               direction, consent, order, bond, debenture, note, coupon, other
               evidence of indebtedness or other paper or document, but the
               Trustee, in its discretion, may make such further inquiry or
               investigation into such facts or matters as it may see fit, and,
               if the Trustee shall determine to make such further inquiry or
               investigation, it shall be entitled to examine the books,
               records and premises of the Company, personally or by agent or
               attorney;

         (g)   the Trustee may execute any of the trusts or powers hereunder or
               perform any duties hereunder either directly or by or through
               agents or attorneys and, except for any Affiliates of the
               Trustee, the Trustee shall not be responsible for any misconduct
               or negligence on the part of any agent or attorney appointed
               with due care by it hereunder;

         (h)   the Trustee shall not be charged with knowledge of any Default
               or Event of Default with respect to the Securities of any series
               for which it is acting as Trustee unless either (1) a
               Responsible Officer shall have actual knowledge of such Default
               or Event of Default or (2) written notice of such Default or
               Event of Default shall have been given to the Trustee by the
               Company or any other obligor on such Securities or by any Holder
               of such Securities; and

         (i)   the Trustee shall not be liable for any action taken, suffered
               or omitted by it in good faith and believed by it to be
               authorized or within the discretion or rights or powers
               conferred upon it by this Indenture.


                                     - 31 -

<PAGE>   41


         SECTION 604. Not Responsible for Recitals or Issuance of Securities.

         The recitals contained herein and in the Securities, except the
Trustee's certificates of authentication, shall be taken as the statements of
the Company, and the Trustee assumes no responsibility for their correctness.
The Trustee makes no representations as to the validity or sufficiency of this
Indenture or of the Securities. The Trustee shall not be accountable for the
use or application by the Company of Securities or the proceeds thereof.

         SECTION 605. May Hold Securities.

         The Trustee, any Authenticating Agent, any Paying Agent, any Security
Registrar or any other agent of the Company, in its individual or any other
capacity, may become the owner or pledgee of Securities and, subject to
Sections 608 and 613, may otherwise deal with the Company with the same rights
it would have if it were not Trustee, Authenticating Agent, Paying Agent,
Security Registrar or such other agent.

         SECTION 606. Money Held in Trust.

         Money held by the Trustee in trust hereunder need not be segregated
from other funds except to the extent required by law. The Trustee shall be
under no liability for interest on any money received by it hereunder except as
otherwise agreed in writing with the Company.

         SECTION 607. Compensation and Reimbursement.

         The Company agrees

         (1)   to pay to the Trustee from time to time reasonable compensation
               for all services rendered by it hereunder (which compensation
               shall not be limited by any provision of law in regard to the
               compensation of a trustee of an express trust);

         (2)   except as otherwise expressly provided herein, to reimburse the
               Trustee upon its request for all reasonable expenses,
               disbursements and advances incurred or made by the Trustee in
               accordance with any provision of this Indenture (including the
               reasonable compensation and the reasonable expenses and
               disbursements of its agents and counsel), except any such
               expense, disbursement or advance as may be attributable to its
               negligence or bad faith; and

         (3)   to indemnify the Trustee and each of its directors, officers,
               employees, agents and/or representatives for, and to hold each
               of them harmless against, any loss, liability or expense
               incurred without negligence or bad faith on each of their part,
               arising out of or in connection with the acceptance or
               administration of the trust or trusts hereunder, including the
               costs and expenses of defending themselves against any claim or
               liability in connection with the exercise or performance of any
               of the Trustees' powers or duties hereunder.

         As security for the performance of the obligations of the Company
under this Section 607, the Trustee shall have a lien prior to the Securities
on all property and funds held or collected by the Trustee as such, except
funds held in trust for the payment of principal of, premium (if any) or
interest on or any Additional Amounts with respect to particular Securities.

         Any expenses and compensation for any services rendered by the Trustee
after the occurrence of an Event of Default specified in clause (5) or (6) of
Section 501 shall constitute expenses and compensation for services of
administration under all applicable federal or state bankruptcy, insolvency,
reorganization or other similar laws.

         The provisions of this Section 607 and any lien arising hereunder
shall survive the resignation or removal of the Trustee or the discharge of the
Company's obligations under this Indenture and the termination of this
Indenture.


                                     - 32 -

<PAGE>   42


         SECTION 608. Disqualification; Conflicting Interests.

         (a)   If the Trustee has or shall acquire any conflicting interest, as
               defined in this Section 608, with respect to the Securities of
               any series, it shall, within 90 days after ascertaining that it
               has such conflicting interest, either eliminate such conflicting
               interest or resign with respect to the Securities of that series
               in the manner and with the effect hereinafter specified in this
               Article Six.

         (b)   In the event that the Trustee shall fail to comply with the
               provisions of subsection (a) of this Section 608 with respect to
               the Securities of any series, the Trustee shall, within 10 days
               after the expiration of such 90-day period, transmit by mail to
               all Holders of Securities of that series, as their names and
               addresses appear in the Security Register, notice of such
               failure.

         (c)   For the purposes of this Section 608, the term "conflicting
               interest" shall have the meaning specified in Section 310(b) of
               the Trust Indenture Act and the Trustee shall comply with
               Section 310(b) of the Trust Indenture Act; provided, that there
               shall be excluded from the operation of Section 310(b)(1) of the
               Trust Indenture Act with respect to the Securities of any series
               any indenture or indentures under which other securities, or
               certificates of interest or participation in other securities,
               of the Company are outstanding, if the requirements for such
               exclusion set forth in Section 310(b)(1) of the Trust Indenture
               Act are met. For purposes of the preceding sentence, the
               optional provision permitted by the second sentence of Section
               310(b)(9) of the Trust Indenture Act shall be applicable.

         SECTION 609. Corporate Trustee Required; Eligibility.

         There shall at all times be a Trustee hereunder which shall be a
corporation organized and doing business under the laws of the United States of
America, any State thereof or the District of Columbia, authorized under such
laws to exercise corporate trust powers, having a combined capital and surplus
of at least $50 million and subject to supervision or examination by federal or
state (or the District of Columbia) authority. If such corporation publishes
reports of condition at least annually, pursuant to law or to the requirements
of said supervising or examining authority, then for the purposes of this
Section 609, the combined capital and surplus of such corporation shall be
deemed to be its combined capital and surplus as set forth in its most recent
report of condition so published. If at any time the Trustee shall cease to be
eligible in accordance with the provisions of this Section 609, it shall resign
immediately in the manner and with the effect hereinafter specified in this
Article Six.

         The Indenture shall always have a Trustee who satisfies the
requirements of Sections 310(a)(1), 310(a)(2) and 310(a)(5) of the Trust
Indenture Act.

         SECTION 610. Resignation and Removal; Appointment of Successor.

         (a)   No resignation or removal of the Trustee and no appointment of a
               successor Trustee pursuant to this Article Six shall become
               effective until the acceptance of appointment by the successor
               Trustee in accordance with the applicable requirements of
               Section 611.

         (b)   The Trustee may resign at any time with respect to the
               Securities of one or more series by giving written notice
               thereof to the Company. If the instrument of acceptance by a
               successor Trustee required by Section 611 shall not have been
               delivered to the resigning Trustee within 30 days after the
               giving of such notice of resignation, the resigning Trustee may
               petition any court of competent jurisdiction for the appointment
               of a successor Trustee with respect to the Securities of such
               series.

         (c)   The Trustee may be removed at any time with respect to the
               Securities of any series by Act of the


                                     - 33 -

<PAGE>   43


               Holders of a majority in principal amount of the Outstanding
               Securities of such series, delivered to the Trustee and to the
               Company.

         (d)   If at any time:

               (1) the Trustee shall fail to comply with Section 608(a) after
                   written request therefor by the Company or by any Holder who
                   has been a bona fide Holder of a Security for at least six
                   months, or

               (2) the Trustee shall cease to be eligible under Section 609 and
                   shall fail to resign after written request therefor by the
                   Company or by any such Holder of Securities, or

               (3) the Trustee shall become incapable of acting or shall be
                   adjudged a bankrupt or insolvent or a receiver of the
                   Trustee or of its property shall be appointed or any public
                   officer shall take charge or control of the Trustee or of
                   its property or affairs for the purpose of rehabilitation,
                   conservation or liquidation, then, in any such case, (i) the
                   Company by a Board Resolution may remove the Trustee with
                   respect to all Securities, or (ii) subject to Section 514,
                   any Holder who has been a bona fide Holder of a Security for
                   at least six months may, on behalf of himself and all others
                   similarly situated, petition any court of competent
                   jurisdiction for the removal of the Trustee with respect to
                   all Securities and the appointment of a successor Trustee or
                   Trustees.

         (e)   If the Trustee shall resign, be removed or become incapable of
               acting, or if a vacancy shall occur in the office of Trustee for
               any cause, with respect to the Securities of one or more series,
               the Company, by a Board Resolution, shall promptly appoint a
               successor Trustee or Trustees with respect to the Securities of
               that or those series (it being understood that any such
               successor Trustee may be appointed with respect to the
               Securities of one or more or all of such series and that at any
               time there shall be only one Trustee with respect to the
               Securities of any particular series) and such successor Trustee
               or Trustees shall comply with the applicable requirements of
               Section 611. If no successor Trustee with respect to the
               Securities of any series shall have been so appointed by the
               Company and accepted appointment in the manner required by
               Section 611, any Holder who has been a bona fide Holder of a
               Security of such series for at least six months may, on behalf
               of himself and all others similarly situated, petition any court
               of competent jurisdiction for the appointment of a successor
               Trustee with respect to the Securities of such series.

         (f)   The Company shall give notice of each resignation and each
               removal of the Trustee with respect to the Securities of any
               series and each appointment of a successor Trustee with respect
               to the Securities of any series by mailing written notice of
               such event by first-class mail, postage prepaid, to all Holders
               of Securities of such series as their names and addresses appear
               in the Security Register. Each notice shall include the name of
               the successor Trustee with respect to the Securities of such
               series and the address of its Corporate Trust Office.

         SECTION 611.      Acceptance of Appointment by Successor.

         (a)      In case of the appointment hereunder of a successor Trustee
                  with respect to all Securities, every such successor Trustee
                  so appointed shall execute, acknowledge and deliver to the
                  Company and to the retiring Trustee an instrument accepting
                  such appointment, and thereupon the resignation or removal of
                  the retiring Trustee shall become effective and such successor
                  Trustee, without any further act, deed or conveyance, shall
                  become vested with all the rights, powers, trusts and duties
                  of the retiring Trustee; but, on the request of the Company or
                  the successor Trustee, such retiring Trustee shall, upon
                  payment of its charges, execute and deliver an instrument
                  transferring to such successor Trustee all


                                     - 34 -

<PAGE>   44


                   the rights, powers and trusts of the retiring Trustee and
                   shall duly assign, transfer and deliver to such successor
                   Trustee all property and money held by such retiring Trustee
                   hereunder.

         (b)       In case of the appointment hereunder of a successor Trustee
                   with respect to the Securities of one or more (but not all)
                   series, the Company, the retiring Trustee and each successor
                   Trustee with respect to the Securities of one or more series
                   shall execute and deliver an indenture supplemental hereto
                   wherein each successor Trustee shall accept such appointment
                   and which (1) shall contain such provisions as shall be
                   necessary or desirable to transfer and confirm to, and to
                   vest in, each successor Trustee all the rights, powers,
                   trusts and duties of the retiring Trustee with respect to
                   the Securities of that or those series to which the
                   appointment of such successor Trustee relates, (2) if the
                   retiring Trustee is not retiring with respect to all
                   Securities, shall contain such provisions as shall be deemed
                   necessary or desirable to confirm that all the rights,
                   powers, trusts and duties of the retiring Trustee with
                   respect to the Securities of that or those series as to
                   which the retiring Trustee is not retiring shall continue to
                   be vested in the retiring Trustee and (3) shall add to or
                   change any of the provisions of this Indenture as shall be
                   necessary to provide for or facilitate the administration of
                   the trusts hereunder by more than one Trustee, it being
                   understood that nothing herein or in such supplemental
                   indenture shall constitute such Trustees co-trustees of the
                   same trust and that each such Trustee shall be trustee of a
                   trust or trusts hereunder separate and apart from any trust
                   or trusts hereunder administered by any other such Trustee;
                   and upon the execution and delivery of such supplemental
                   indenture, the resignation or removal of the retiring
                   Trustee shall become effective to the extent provided
                   therein and each such successor Trustee, without any further
                   act, deed or conveyance, shall become vested with all the
                   rights, powers, trusts and duties of the retiring Trustee
                   with respect to the Securities of that or those series to
                   which the appointment of such successor Trustee relates;
                   but, on request of the Company or any successor Trustee,
                   such retiring Trustee shall duly assign, transfer and
                   deliver to such successor Trustee all property and money
                   held by such retiring Trustee hereunder with respect to the
                   Securities of that or those series to which the appointment
                   of such successor Trustee relates.

         (c)       Upon request of any such successor Trustee, the Company
                   shall execute any and all instruments for more fully and
                   certainly vesting in and confirming to such successor
                   Trustee all such rights, powers and trusts referred to in
                   paragraph (a) or (b) of this Section 611, as the case may
                   be.

         (d)       No successor Trustee shall accept its appointment unless at
                   the time of such acceptance such successor Trustee shall be
                   qualified and eligible under this Article Six.

         SECTION 612. Merger, Conversion, Consolidation or Succession to
Business.

         Any corporation into which the Trustee may be merged or converted or
with which it may be consolidated, or any corporation resulting from any
merger, conversion or consolidation to which the Trustee shall be a party, or
any corporation succeeding to all or substantially all the corporate trust
business of the Trustee, shall be the successor of the Trustee hereunder,
provided such corporation shall be otherwise qualified and eligible under this
Article Six, without the execution or filing of any paper or any further act on
the part of any of the parties hereto. In case any Securities shall have been
authenticated, but not delivered, by the Trustee then in office, any successor
by merger, conversion or consolidation to such authenticating Trustee may adopt
such authentication and deliver the Securities so authenticated with the same
effect as if such successor Trustee had itself authenticated such Securities.

         SECTION 613. Preferential Collection of Claims Against Company.

         The Trustee shall comply with Section 311(a) of the Trust Indenture
Act, excluding any creditor relationship described in Section 311(b) of the
Trust Indenture Act. A Trustee who has resigned or been removed shall be
subject to Section 311(a) of the Trust Indenture Act to the extent indicated
therein.


                                     - 35 -

<PAGE>   45


         SECTION 614. Appointment of Authenticating Agent.

         The Trustee may appoint an Authenticating Agent or Agents that shall
be authorized to act on behalf of the Trustee to authenticate Securities issued
upon original issue and upon exchange, registration of transfer or partial
redemption or pursuant to Section 306, and Securities so authenticated shall be
entitled to the benefits of this Indenture and shall be valid and obligatory
for all purposes as if authenticated by the Trustee hereunder. Wherever
reference is made in this Indenture to the authentication and delivery of
Securities by the Trustee or the Trustee's certificate of authentication, such
reference shall be deemed to include authentication and delivery on behalf of
the Trustee by an Authenticating Agent and a certificate of authentication
executed on behalf of the Trustee by an Authenticating Agent. Each
Authenticating Agent shall be acceptable to the Company and shall at all times
be a corporation organized and doing business under the laws of the United
States of America, any state thereof or the District of Columbia, having a
combined capital and surplus of not less than $50 million or equivalent amount
expressed in a foreign currency and subject to supervision or examination by
federal or state (or the District of Columbia) authority or authority of such
country. If such Authenticating Agent publishes reports of condition at least
annually, pursuant to law or to the requirements of said supervising or
examining authority, then for the purposes of this Section 614, the combined
capital and surplus of such Authenticating Agent shall be deemed to be its
combined capital and surplus as set forth in its most recent report of
condition so published. If at any time an Authenticating Agent shall cease to
be eligible in accordance with the provisions of this Section 614, such
Authenticating Agent shall resign immediately in the manner and with the effect
specified in this Section 614.

         Any corporation into which an Authenticating Agent may be merged or
converted or with which it may be consolidated, or any corporation resulting
from any merger, conversion or consolidation to which such Authenticating Agent
shall be a party, or any corporation succeeding to the corporate agency or
corporate trust business of an Authenticating Agent, shall continue to be an
Authenticating Agent, provided such corporation shall be otherwise eligible
under this Section 614, without the execution or filing of any paper or any
further act on the part of the Trustee or the Authenticating Agent.

         An Authenticating Agent may resign at any time by giving written
notice thereof to the Trustee and to the Company. The Trustee may at any time
terminate the agency of an Authenticating Agent by giving written notice
thereof to such Authenticating Agent and to the Company. Upon receiving such a
notice of resignation or upon such a termination, or in case at any time such
Authenticating Agent shall cease to be eligible in accordance with the
provisions of this Section 614, the Trustee may appoint a successor
Authenticating Agent which shall be acceptable to the Company and shall mail
written notice of such appointment by first-class mail, postage prepaid, to all
Holders as their names and addresses appear in the Security Register. Any
successor Authenticating Agent upon acceptance of its appointment hereunder
shall become vested with all the rights, powers and duties of its predecessor
hereunder, with like effect as if originally named as an Authenticating Agent.
No successor Authenticating Agent shall be appointed unless eligible under the
provisions of this Section 614.

         The Company agrees to pay to each Authenticating Agent from time to
time reasonable compensation for its services under this Section 614.

         If an appointment is made pursuant to this Section 614, the Securities
may have endorsed thereon, in addition to the Trustee's certificate of
authentication, an alternate certificate of authentication in the following
form:



                                     - 36 -

<PAGE>   46


         This is one of the Securities of the series designated therein
referred to in the within-mentioned Indenture.



                                        ---------------------------------------
                                        As Trustee


                                        By
                                                -------------------------------
                                                   As Authenticating Agent


                                        By
                                                -------------------------------
                                                   Authorized Signatory

         Notwithstanding any provision of this Section 614 to the contrary, if
at any time any Authenticating Agent appointed hereunder with respect to any
series of Securities shall not also be acting as the Security Registrar
hereunder with respect to any series of Securities, then, in addition to all
other duties of an Authenticating Agent hereunder, such Authenticating Agent
shall also be obligated: (i) to furnish to the Security Registrar promptly all
information necessary to enable the Security Registrar to maintain at all times
an accurate and current Security Register; and (ii) prior to authenticating any
Security denominated in a foreign currency, to ascertain from the Company the
units of such foreign currency that are required to be determined by the
Company pursuant to Section 302.

                                 ARTICLE SEVEN

               HOLDER'S LISTS AND REPORTS BY TRUSTEE AND COMPANY

    SECTION 701. Company to Furnish Trustee Names and Addresses of Holders.

         With respect to each series of Securities, the Company will furnish or
cause to be furnished to the Trustee:

         (a)   semi-annually, not more than 15 days after each Regular Record
               Date relating to that series (or, if there is no Regular Record
               Date relating to that series, on January 1 and July 1), a list,
               in such form as the Trustee may reasonably require, of the names
               and addresses of the Holders of that series as of such dates,
               and

         (b)   at such other times as the Trustee may request in writing,
               within 30 days after the receipt by the Company of any such
               request, a list of similar form and content, such list to be
               dated as of a date not more than 15 days prior to the time such
               list is furnished; provided, that so long as the Trustee is the
               Security Registrar, the Company shall not be required to furnish
               or cause to be furnished such a list to the Trustee. The Company
               shall otherwise comply with Section 310(a) of the Trust
               Indenture Act.

         SECTION 702. Preservation of Information; Communications to Holders.

         (a)   The Trustee shall preserve, in as current a form as is
               reasonably practicable, the names and addresses of Holders of
               each series contained in the most recent list furnished to the
               Trustee as provided in Section 701 and the names and addresses
               of Holders of each series received by the Trustee in its
               capacity as Security Registrar. The Trustee may destroy any list
               furnished to it as provided in Section 701 upon receipt of a new
               list so furnished. The Trustee shall otherwise comply with
               Section 310(a) of the Trust Indenture Act.



                                     - 37 -

<PAGE>   47


         (b)   Holders of Securities may communicate pursuant to Section 312(b)
               of the Trust Indenture Act with other Holders with respect to
               their rights under this Indenture or under the Securities. The
               Company, the Trustee, the Security Registrar and any other
               Person shall have the protection of Section 312(c) of the Trust
               Indenture Act.

         SECTION 703. Reports by Trustee.

         (a)   Within 60 days after May 15 of each year after the execution of
               this Indenture, the Trustee shall transmit by mail to Holders a
               brief report dated as of such May 15 that complies with Section
               313(a) of the Trust Indenture Act. The Trustee shall comply with
               Section 313(b) of the Trust Indenture Act. The Trustee shall
               transmit by mail all reports as required by Sections 313(c) and
               313(d) of the Trust Indenture Act.

         (b)   A copy of each report pursuant to subsection (a) of this Section
               703 shall, at the time of its transmission to Holders, be filed
               by the Trustee with each stock exchange upon which any
               Securities are listed, with the Commission and with the Company.
               The Company will notify the Trustee when any Securities are
               listed on any stock exchange.

         SECTION 704. Reports by Company.

         The Company shall file with the Trustee, within 15 days after the
Company is required to file the same with the Commission, copies of the annual
reports and of the information, documents and other reports (or copies of such
portions of any of the foregoing as the Commission may from time to time by
rules and regulations prescribe) which the Company may be required to file with
the Commission pursuant to Section 13 or Section 15(d) of the Securities
Exchange Act of 1934, as amended, and shall otherwise comply with Section
314(a) of the Trust Indenture Act.

                                 ARTICLE EIGHT

              CONSOLIDATION, MERGER, CONVEYANCE, TRANSFER OR LEASE

         SECTION 801. Company May Consolidate, Etc., Only on Certain Terms.

         The Company shall not consolidate with or merge into any other Person
or convey, transfer or lease its properties and assets substantially as an
entirety to any Person, unless:

         (1)   the Person formed by such consolidation or into which the
               Company is merged or the Person which acquires by conveyance or
               transfer, or which leases, the properties and assets of the
               Company substantially as an entirety shall be a corporation,
               partnership or trust, shall be organized and existing under the
               laws of the United States of America, any State thereof or the
               District of Columbia and shall expressly assume, by an indenture
               supplemental hereto, executed and delivered to the Trustee, in
               form satisfactory to the Trustee, the due and punctual payment
               of the principal of, premium (if any) and interest on or any
               Additional Amounts with respect to all the Securities and the
               performance of every covenant of this Indenture on the part of
               the Company to be performed or observed;

         (2)   immediately after giving effect to such transaction, and
               treating any indebtedness that becomes Indebtedness of the
               Company or a Subsidiary of the Company as a result of such
               transaction as having been incurred by the Company or such
               Subsidiary at the time of such transaction, no Default or Event
               of Default, shall have happened and be continuing; and

         (3)   the Company has delivered to the Trustee an Officers'
               Certificate and an Opinion of Counsel, each stating that such
               consolidation, merger, conveyance, transfer or lease and, if a
               supplemental indenture


                                     - 38 -

<PAGE>   48


               is required in connection with such transaction, such
               supplemental indenture comply with this Article Eight and that
               all conditions precedent herein provided for relating to such
               transaction have been complied with.

         SECTION 802. Successor Person Substituted.

         Upon any consolidation by the Company with or merger by the Company
into any other Person or any conveyance, transfer or lease of the properties
and assets of the Company substantially as an entirety in accordance with
Section 801, the successor Person formed by such consolidation or into which
the Company is merged or to which such conveyance, transfer or lease is made
shall succeed to, and be substituted for, and may exercise every right and
power of, the Company under this Indenture with the same effect as if such
successor Person had been named as the Company herein, and thereafter, except
in the case of such lease, the predecessor Person shall be relieved of all
obligations and covenants under this Indenture and the Securities.

                                  ARTICLE NINE

                            SUPPLEMENTAL INDENTURES

         SECTION 901. Supplemental Indentures Without Consent of Holders.

         Without the consent of any Holders, the Company, when authorized by a
Board Resolution, and the Trustee, at any time and from time to time, may enter
into one or more indentures supplemental hereto, in form satisfactory to the
Trustee, for any of the following purposes:

         (1)   to evidence the succession of another Person to the Company and
               the assumption by any such successor of the covenants of the
               Company herein and in the Securities; or

         (2)   to add to the covenants of the Company for the benefit of the
               Holders of all or any series of Securities (and if such
               covenants are to be for the benefit of less than all series of
               Securities, stating that such covenants are expressly being
               included solely for the benefit of such series) to convey,
               transfer, assign, mortgage or pledge any property to or with the
               Trustee or otherwise secure any series of the Securities or to
               surrender any right or power herein conferred upon the Company;
               or

         (3)   to add any additional Events of Default with respect to all or
               any series of the Securities (and, if such Event of Default is
               applicable to less than all series of Securities, specifying the
               series to which such Event of Default is applicable); or

         (4)   to change or eliminate any of the provisions of this Indenture,
               provided that any such change or elimination shall become
               effective only when there is no Security Outstanding of any
               series created prior to the execution of such supplemental
               indenture which is adversely affected by such change in or
               elimination of such provision; or

         (5)   to secure the Securities; or

         (6)   to supplement any of the provisions of this Indenture to such
               extent as shall be necessary to permit or facilitate the
               defeasance and discharge of any series of Securities pursuant to
               Section 401; provided, however, that any such action shall not
               adversely affect the interest of the Holders of Securities of
               such series or any other series of Securities in any material
               respect; or

         (7)   to establish the form or terms of Securities of any series as
               permitted by Sections 201 and 301; or



                                     - 39 -

<PAGE>   49


         (8)   to evidence and provide for the acceptance of appointment
               hereunder by a successor Trustee with respect to the Securities
               of one or more series and to add to or change any of the
               provisions of this Indenture as shall be necessary to provide
               for or facilitate the administration of the trusts hereunder by
               more than one Trustee, pursuant to the requirements of Section
               611(b); or

         (9)   to cure any ambiguity, to correct or supplement any provision
               herein which may be defective or inconsistent with any other
               provision herein, or to make any other provisions with respect
               to matters or questions arising under this Indenture, provided
               such other provisions as may be made shall not adversely affect
               the interests of the Holders of Securities of any series in any
               material respect.

         SECTION 902. Supplemental Indentures With Consent of Holders.

         With the consent of the Holders of a majority in principal amount of
the Outstanding Securities of all series affected by such supplemental
indenture (acting as one class), by Act of said Holders delivered to the
Company and the Trustee, the Company, when authorized by a Board Resolution,
and the Trustee may enter into an indenture or indentures supplemental hereto
for the purpose of adding any provisions to or changing in any manner or
eliminating any of the provisions of this Indenture or of modifying in any
manner the rights of the Holders of Securities of such series under this
Indenture; provided, however, that no such supplemental indenture shall,
without the consent of the Holder of each Outstanding Security affected
thereby,

         (1)   change the Stated Maturity of the principal of, or any
               installment of principal of or interest on, any Security, or
               reduce the principal amount thereof or the rate of interest
               thereon, any Additional Amounts with respect thereto or any
               premium payable upon the redemption thereof, or change any
               obligation of the Company to pay Additional Amounts (except as
               contemplated by Section 801(1) and permitted by Section 901(1)),
               or reduce the amount of the principal of an Original Issue
               Discount Security that would be due and payable upon a
               declaration of acceleration of the Maturity thereof pursuant to
               Section 502, or change any Place of Payment where, or the coin
               or currency or currencies (including composite currencies) in
               which, any Security or any premium or any interest thereon or
               Additional Amounts with respect thereto is payable, or impair
               the right to institute suit for the enforcement of any such
               payment on or after the Stated Maturity thereof (or, in the case
               of redemption, on or after the Redemption Date),

         (2)   reduce the percentage in principal amount of Outstanding
               Securities, the consent of whose Holders is required for any
               such supplemental indenture, or the consent of whose Holders is
               required for any waiver (of compliance with certain provisions
               of this Indenture or certain defaults hereunder and their
               consequences) provided for in this Indenture, or

         (3)   modify any of the provisions of this Section 902, Section 513 or
               Section 1006, except to increase any such percentage or to
               provide with respect to any particular series the right to
               condition the effectiveness of any supplemental indenture as to
               that series on the consent of the Holders of a specified
               percentage of the aggregate principal amount of Outstanding
               Securities of such series (which provision may be made pursuant
               to Section 301 without the consent of any Holder) or to provide
               that certain other provisions of this Indenture cannot be
               modified or waived without the consent of the Holder of each
               Outstanding Security affected thereby, provided, however, that
               this clause (3) shall not be deemed to require the consent of
               any Holder with respect to changes in the references to "the
               Trustee" and concomitant changes in this Section 902 and Section
               1006, or the deletion of this proviso, in accordance with the
               requirements of Section 611(b) and Section 901(7).

A supplemental indenture which changes or eliminates any covenant or other
provision of this Indenture which has expressly been included solely for the
benefit of one or more particular series of Securities, or which modifies the
rights of the Holders of Securities of such series with respect to such
covenant or other provision, shall be deemed not to affect the rights under
this Indenture of the Holders of Securities of any other series.


                                     - 40 -

<PAGE>   50




         It shall not be necessary for any Act of Holders under this Section
902 to approve the particular form of any proposed supplemental indenture, but
it shall be sufficient if such Act shall approve the substance thereof.

         SECTION 903. Execution of Supplemental Indentures.

         In executing, or accepting the additional trusts created by, any
supplemental indenture permitted by this Article Nine or the modifications
thereby of the trusts created by this Indenture, the Trustee shall be entitled
to receive, and (subject to Section 601) shall be fully protected in relying
upon an Opinion of Counsel stating that the execution of such supplemental
indenture is authorized or permitted by this Indenture. The Trustee may, but
shall not be obligated to, enter into any such supplemental indenture which
affects the Trustee's own rights, duties, immunities or liabilities under this
Indenture or otherwise.

         SECTION 904. Effect of Supplemental Indentures.

         Upon the execution of any supplemental indenture under this Article
Nine, this Indenture shall be modified in accordance therewith, and such
supplemental indenture shall form a part of this Indenture for all purposes;
and every Holder of Securities theretofore or thereafter authenticated and
delivered hereunder shall be bound thereby.

         SECTION 905. Conformity With Trust Indenture Act.

         Every supplemental indenture executed pursuant to this Article Nine
shall conform to the requirements of the Trust Indenture Act as then in effect.

         SECTION 906. Reference in Securities to Supplemental Indentures.

         Securities of any series authenticated and delivered after the
execution of any supplemental indenture pursuant to this Article Nine may, and
shall if required by the Trustee, bear a notation in form approved by the
Trustee as to any matter provided for in such supplemental indenture. If the
Company shall so determine, new Securities of any series so modified as to
conform, in the opinion of the Trustee and the Company, to any such
supplemental indenture may be prepared and executed by the Company and
authenticated and delivered by the Trustee in exchange for Outstanding
Securities of such series.

                                  ARTICLE TEN

                                   COVENANTS

         SECTION 1001. Payment of Principal, Premium and Interest.

         The Company covenants and agrees for the benefit of the Holders of
each series of Securities that it will duly and punctually pay the principal
of, premium (if any) and interest on [and any Additional Amounts with respect
to] the Securities of that series in accordance with the terms of the
Securities and this Indenture.

         SECTION 1002. Maintenance of Office or Agency.

         The Company will maintain in each Place of Payment for any series of
Securities an office or agency where Securities of that series may be presented
or surrendered for payment, where Securities of that series may be surrendered
for registration of transfer or exchange and where notices and demands to or
upon the Company in respect of the Securities of that series and this Indenture
may be served. The Company will give prompt written notice to the Trustee of
the location, and any change in the location, of such office or agency. If at
any time the Company shall fail to


                                     - 41 -

<PAGE>   51


maintain any such required office or agency or shall fail to furnish the
Trustee with the address thereof, such presentations, surrenders, notices and
demands may be made or served at the Corporate Trust Office of the Trustee and
the Company hereby appoints the Trustee its agent to receive all presentations,
surrenders, notices and demands.

         The Company may also from time to time designate one or more other
offices or agencies where the Securities of one or more series may be presented
or surrendered for any or all such purposes and may from time to time rescind
such designations; provided, however, that no such designation or rescission
shall in any manner relieve the Company of its obligation to maintain an office
or agency in each Place of Payment for Securities of any series for such
purposes. The Company will give prompt written notice to the Trustee of any
such designation or rescission and of any change in the location of any such
other office or agency.

         SECTION 1003. Money for Securities Payments to be Held in Trust.

         If the Company, any Subsidiary or any of their respective Affiliates
shall at any time act as Paying Agent with respect to any series of Securities,
such Paying Agent will, on or before each due date of the principal of, premium
(if any) or interest on or any Additional Amounts with respect to any of the
Securities of that series, segregate and hold in trust for the benefit of the
Persons entitled thereto a sum sufficient to pay the principal, premium (if
any) or interest or any Additional Amounts so becoming due until such sums
shall be paid to such Persons or otherwise disposed of as herein provided and
will promptly notify the Trustee of its action or failure so to act.

         Whenever the Company shall have one or more Paying Agents for any
series of Securities, the Company will, on or before each due date of the
principal of, premium (if any) or interest on any Securities of that series,
deposit with a Paying Agent a sum sufficient to pay the principal of, premium
(if any) or interest so becoming due, such sum to be held in trust for the
benefit of the Persons entitled to such principal, premium or interest, and
(unless such Paying Agent is the Trustee) the Company will promptly notify the
Trustee of its action or failure so to act.

         The Company will cause each Paying Agent for any series of Securities
other than the Trustee to execute and deliver to the Trustee an instrument in
which such Paying Agent shall agree with the Trustee, subject to the provisions
of this Section 1003, that such Paying Agent will:

         (1)   hold all sums held by it for the payment of the principal of,
               premium (if any) or interest on or any Additional Amounts with
               respect to Securities of that series in trust for the benefit of
               the Persons entitled thereto until such sums shall be paid to
               such Persons or otherwise disposed of as herein provided;

         (2)   give the Trustee notice of any default by the Company (or any
               other obligor upon the Securities of that series) in the making
               of any payment of principal of, premium (if any) or interest on
               or any Additional Amounts with respect to the Securities of that
               series; and

         (3)   at any time during the continuance of any such default, upon the
               written request of the Trustee, forthwith pay to the Trustee all
               sums so held in trust by such Paying Agent.

         The Company may at any time, for the purpose of obtaining the
satisfaction and discharge of this Indenture or for any other purpose, pay, or
by Company Order direct any Paying Agent to pay, to the Trustee all sums held
in trust by the Company or such Paying Agent, such sums to be held by the
Trustee upon the same trusts as those upon which sums were held by the Company
or such Paying Agent; and, upon such payment by any Paying Agent to the
Trustee, such Paying Agent shall be released from all further liability with
respect to such money.

         Any money deposited with the Trustee or any Paying Agent, or then held
by the Company, in trust for the payment of the principal of, premium (if any)
or interest on or any Additional Amounts with respect to any Security of any
series and remaining unclaimed for three years after such principal of, premium
(if any) or interest on or any


                                     - 42 -

<PAGE>   52


Additional Amounts with respect to any Securities have become due and payable
shall, unless otherwise required by mandatory provisions of applicable escheat,
or abandoned or unclaimed property law, be paid to the Company on Company
Request, or (if then held by the Company) shall be discharged from such trust;
and the Holder of such Security shall thereafter, as an unsecured general
creditor, look only to the Company for payment thereof, and all liability of
the Trustee or such Paying Agent with respect to such trust money, and all
liability of the Company as trustee thereof, shall thereupon cease; provided,
however, that the Trustee or such Paying Agent, before being required to make
any such repayment, may at the expense of the Company cause to be published
once, in an Authorized Newspaper in The Borough of Manhattan, The City of New
York and in such other Authorized Newspapers as the Trustee shall deem
appropriate, notice that such money remains unclaimed and that, after a date
specified herein, which shall not be less than 30 days from the date of such
publication, any unclaimed balance of such money then remaining will, unless
otherwise required by mandatory provisions of applicable escheat, or abandoned
or unclaimed property law, be repaid to the Company.

         SECTION 1004. Existence.

         Subject to Article Eight, the Company will do or cause to be done all
things necessary to preserve and keep in full force and effect its corporate
existence.

         SECTION 1005. Statement by Officers as to Default.

         The Company will deliver to the Trustee, within 120 days after the end
of each fiscal year of the Company ending after the date hereof so long as any
Security is outstanding hereunder, an Officers' Certificate, complying with
Section 314(a)(4) of the Trust Indenture Act and stating that a review of the
activities of the Company during such year and of performance under this
Indenture has been made under the supervision of the signers thereof and
whether or not to the best of their knowledge, based upon such review, the
Company is in default in the performance, observance or fulfillment of any of
its covenants and other obligations under this Indenture, and if the Company
shall be in default, specifying each such default known to them and the nature
and status thereof. One of the officers signing the Officers' Certificate
delivered pursuant to this Section 1005 shall be the principal executive,
financial or accounting officer of the Company.

         For purposes of this Section 1005, such compliance shall be determined
without regard to any period of grace or requirement of notice provided under
this Indenture.

         SECTION 1006. Waiver of Certain Covenants.

         The Company may omit in any particular instance to comply with any
covenant or condition set forth in Sections 1001 through 1005, inclusive, or
any covenant added for the benefit of any series of Securities as contemplated
by Section 301 (unless otherwise specified pursuant to Section 301) if before
or after the time for such compliance the Holders of a majority in principal
amount of the Outstanding Securities of all series affected by such omission
(acting as one class) shall, by Act of such Holders, either waive such
compliance in such instance or generally waive compliance with such covenant or
condition, but no such waiver shall extend to or affect such covenant or
condition except to the extent so expressly waived, and, until such waiver
shall become effective, the obligations of the Company and the duties of the
Trustee in respect of any such covenant or condition shall remain in full force
and effect.

         SECTION 1007. Additional Amounts.

         If the Securities of a series expressly provide for the payment of
Additional Amounts, the Company will pay to the Holder of any Security of such
series Additional Amounts as expressly provided therein. Whenever in this
Indenture there is mentioned, in any context, the payment of the principal of,
or premium (if any) or interest on any Security of any series or the net
proceeds received from the sale or exchange of any Security of any series, such
mention shall be deemed to include mention of the payment of Additional Amounts
provided for in this Section 1007 to the


                                     - 43 -

<PAGE>   53


extent that, in such context, Additional Amounts are, were or would be payable
in respect thereof pursuant to the provisions of this Section 1007 and express
mention of the payment of Additional Amounts (if applicable) in any provisions
hereof shall not be construed as excluding Additional Amounts in those
provisions hereof where such express mention is not made.

         If the Securities of a series provide for the payment of Additional
Amounts, at least 10 days prior to the first Interest Payment Date with respect
to that series of Securities (or if the Securities of that series will not bear
interest prior to Maturity, the first day on which a payment of principal and
any premium is made), and at least 10 days prior to each date of payment of
principal and any premium or interest if there has been any change with respect
to the matters set forth in the below-mentioned Officers' Certificate, the
Company shall furnish the Trustee and the Company's principal Paying Agent or
Paying Agents, if other than the Trustee, with an Officers' Certificate
instructing the Trustee and such Paying Agent or Paying Agents whether such
payment of principal of and any premium or interest on the Securities of that
series shall be made to Holders of Securities of that series who are United
States Aliens without withholding for or on account of any tax, assessment or
other governmental charge described in the Securities of that series. If any
such withholding shall be required, then such Officers' Certificate shall
specify by country the amount, if any, required to be withheld on such payments
to such Holders of Securities and the Company will pay to such Paying Agent the
Additional Amounts required by this Section 1007. The Company covenants to
indemnify the Trustee and any Paying Agent for, and to hold them harmless
against any loss, liability or expense reasonably incurred without negligence
or bad faith on their part arising out of or in connection with actions taken
or omitted by any of them in reliance on any Officers' Certificate furnished
pursuant to this Section 1007.

                                 ARTICLE ELEVEN

                            REDEMPTION OF SECURITIES

         SECTION 1101. Applicability of Article.

         Securities of any series which are redeemable before their Stated
Maturity shall be redeemable in accordance with their terms and (except as
otherwise specified as contemplated by Section 301 for Securities of any
series) in accordance with this Article Eleven.

         SECTION 1102. Election to Redeem; Notice to Trustee.

         Unless otherwise provided with respect to the Securities of a series
as contemplated by Section 301, the election of the Company to redeem any
Securities shall be evidenced by a Board Resolution. In case of any redemption
at the election of the Company of less than all the Securities of any series,
the Company shall, a reasonable period prior to the Redemption Date fixed by
the Company (unless a shorter notice shall be satisfactory to the Trustee),
notify the Trustee of such Redemption Date and of the principal amount of
Securities of such series to be redeemed. In the case of any redemption of
Securities prior to the expiration of any restriction on such redemption
provided in the terms of such Securities or elsewhere in this Indenture, the
Company shall furnish the Trustee with an Officers' Certificate evidencing
compliance with such restriction.

         SECTION 1103. Selection by Trustee of Securities to be Redeemed.

         If less than all the Securities of any series are to be redeemed, the
particular Securities to be redeemed shall be selected not more than 60 days
prior to the Redemption Date by the Trustee, from the Outstanding Securities of
such series not previously called for redemption, by such method as the Trustee
shall deem fair and appropriate and that may provide for the selection for
redemption of portions (equal to the minimum authorized denomination for
Securities of that series or any integral multiple thereof) of the principal
amount of Securities of such series of a denomination larger than the minimum
authorized denomination for Securities of that series or of the principal
amount of global Securities of such series.


                                     - 44 -

<PAGE>   54


         The Trustee shall promptly notify the Company and the Security
Registrar in writing of the Securities selected for redemption and, in the case
of any Securities selected for partial redemption, the principal amount thereof
to be redeemed.

         For all purposes of this Indenture, unless the context otherwise
requires, all provisions relating to the redemption of Securities shall relate,
in the case of any Securities redeemed or to be redeemed only in part, to the
portion of the principal amount of such Securities which has been or is to be
redeemed.

         SECTION 1104. Notice of Redemption.

         Notice of redemption shall be given in the manner provided in Section
107 to each Holder of Securities to be redeemed not less than 30 nor more than
60 days prior to the Redemption Date.

         All notices of redemption shall state:

         (1)   the Redemption Date,

         (2)   the Redemption Price,

         (3)   if less than all the Outstanding Securities of any series are to
               be redeemed, the identification (and, in the case of partial
               redemption, the principal amounts) of the particular Securities
               to be redeemed,

         (4)   that on the Redemption Date the Redemption Price will become due
               and payable upon each such Security to be redeemed and, if
               applicable, that interest thereon will cease to accrue on and
               after said date,

         (5)   the place or places where such Securities are to be surrendered
               for payment of the Redemption Price,

         (6)   that the redemption is for a sinking fund, if such is the case,
               and

         (7)   the "CUSIP" number, if applicable.

         A notice of redemption as contemplated by Section 107 need not
identify particular Securities to be redeemed. Notice of redemption of
Securities to be redeemed at the election of the Company shall be given by the
Company or, at the Company's request, by the Trustee in the name and at the
expense of the Company.

         SECTION 1105. Deposit of Redemption Price.

         On or before 10:00 a.m., New York City time, on any Redemption Date,
the Company shall deposit with the Trustee or with a Paying Agent (or, if the
Company is acting as its own Paying Agent, segregate and hold in trust as
provided in Section 1003) an amount of money sufficient to pay the Redemption
Price of, and (except if the Redemption Date shall be an Interest Payment Date)
accrued interest on, and any Additional Amounts with respect to, all the
Securities which are to be redeemed on that date.

         SECTION 1106. Securities Payable on Redemption Date.

         Notice of redemption having been given as aforesaid, the Securities so
to be redeemed shall, on the Redemption Date, become due and payable at the
Redemption Price therein specified, and from and after such date (unless the
Company shall default in the payment of the Redemption Price and accrued
interest) such Securities shall cease to bear interest. Upon surrender of any
such Security for redemption in accordance with said notice, such Security
shall be paid by the Company at the Redemption Price, together with accrued
interest (and any Additional Amounts) to the


                                     - 45 -

<PAGE>   55


Redemption Date; provided, however, that installments of interest whose Stated
Maturity is on or prior to the Redemption Date shall be payable to the Holders
of such Securities, or one or more Predecessor Securities, registered as such
at the close of business on the relevant Record Dates according to their terms
and the provisions of Section 307.

         If any Security called for redemption shall not be so paid upon
surrender thereof for redemption, the principal of and premium (if any) shall,
until paid, bear interest from the Redemption Date at the rate prescribed
therefor in the Security or, in the case of Original Issue Discount Securities,
the Securities' Yield to Maturity.

         SECTION 1107. Securities Redeemed in Part.

         Any Security which is to be redeemed only in part shall be surrendered
at a Place of Payment therefor (with, if the Company or the Trustee so
requires, due endorsement by, or a written instrument of transfer in form
satisfactory to the Company and the Trustee duly executed by, the Holder
thereof or his attorney duly authorized in writing), and the Company shall
execute, and the Trustee shall authenticate and deliver to the Holder of such
Security without service charge, a new Security or Securities of the same
series and Stated Maturity, of any authorized denomination as requested by such
Holder, in aggregate principal amount equal to and in exchange for the
unredeemed portion of the principal of the Security so surrendered.

         Unless otherwise specified as contemplated by Section 301, the Company
and any Affiliate of the Company may at any time purchase or otherwise acquire
Securities in the open market or by private agreement. Such acquisition shall
not operate as or be deemed for any purpose to be a redemption of the
indebtedness represented by such Securities. Any Securities purchased or
acquired by the Company may be delivered to the Trustee and, upon such
delivery, the indebtedness represented thereby shall be deemed to be satisfied.
Section 309 shall apply to all Securities so delivered.

                                 ARTICLE TWELVE

                                 SINKING FUNDS

         SECTION 1201. Applicability of Article.

         The provisions of this Article Twelve shall be applicable to any
sinking fund for the retirement of Securities of a series except as otherwise
specified as contemplated by Section 301 for Securities of such series.

         The minimum amount of any sinking fund payment provided for by the
terms of Securities of any series is herein referred to as a "mandatory sinking
fund payment," and any payment in excess of such minimum amount provided for by
the terms of Securities of any series is herein referred to as an "optional
sinking fund payment". Unless otherwise provided by the terms of Securities of
any series, the cash amount of any sinking fund payment may be subject to
reduction as provided in Section 1202. Each sinking fund payment shall be
applied to the redemption of Securities of any series as provided for by the
terms of Securities of such series.

         SECTION 1202. Satisfaction of Sinking Fund Payments with Securities.

         The Company (1) may deliver Outstanding Securities of a series (other
than any previously called for redemption) and (2) may apply as a credit
Securities of a series which have been redeemed either at the election of the
Company pursuant to the terms of such Securities or through the application of
permitted optional sinking fund payments pursuant to the terms of such
Securities, in each case in satisfaction of all or any part of any sinking fund
payment with respect to the Securities of such series required to be made
pursuant to the terms of such Securities as provided for by the terms of such
series; provided that such Securities have not been previously so credited.
Such Securities shall be received and credited for such purpose by the Trustee
at the Redemption Price specified in such Securities for redemption through
operation of the sinking fund and the amount of such sinking payment shall be
reduced accordingly.


                                     - 46 -

<PAGE>   56


         SECTION 1203. Redemption of Securities for Sinking Fund.

         Not less than 45 days prior (unless a shorter period shall be
satisfactory to the Trustee) to each sinking fund payment date for any series
of Securities, the Company will deliver to the Trustee an Officers' Certificate
specifying the amount of the next ensuing sinking fund payment for that series
pursuant to the terms of that series, the portion thereof, if any, which is to
be satisfied by payment of cash and the portion thereof, if any, which is to be
satisfied by delivery of or by crediting Securities of that series pursuant to
Section 1202 and will also deliver to the Trustee any Securities to be so
delivered. Not less than 30 days before each such sinking fund payment date the
Trustee shall select the Securities to be redeemed upon such sinking fund
payment date in the manner specified in Section 1103 and cause notice of the
redemption thereof to be given in the name of and at the expense of the Company
in the manner provided in Section 1104. Such notice having been duly given, the
redemption of such Securities shall be made upon the terms and in the manner
stated in Sections 1106 and 1107.

                                ARTICLE THIRTEEN

                       MEETINGS OF HOLDERS OF SECURITIES

         SECTION 1301. Purposes for Which Meetings May Be Called.

         A meeting of Holders of Securities of any or all series may be called
at any time and from time to time pursuant to this Article Thirteen to make,
give or take any request, demand, authorization, direction, notice, consent,
waiver or other action provided by this Indenture to be made, given or taken by
Holders of Securities of such series.

         SECTION 1302. Call, Notice and Place of Meetings.

         (a)   The Trustee may at any time call a meeting of Holders of
               Securities of any series for any purpose specified in Section
               1301, to be held at such time and at such place in Houston,
               Texas, in The Borough of Manhattan, The City of New York, or in
               any other location as the Trustee shall determine. Notice of
               every meeting of Holders of Securities of any series, setting
               forth the time and the place of such meeting and in general
               terms the action proposed to be taken at such meeting, shall be
               given, in the manner provided in Section 107, not less than 20
               nor more than 180 days prior to the date fixed for the meeting.

         (b)   In case at any time the Company, pursuant to a Board Resolution,
               or the Holders of at least 10% in aggregate principal amount of
               the Outstanding Securities of any series, shall have requested
               the Trustee for any such series to call a meeting of the Holders
               of Securities of such series for any purpose specified in
               Section 1301, by written request setting forth in reasonable
               detail the action proposed to be taken at the meeting, and the
               Trustee shall not have made the first publication of the notice
               of such meeting within 30 days after receipt of such request or
               shall not thereafter proceed to cause the meeting to be held as
               provided herein, then the Company or the Holders of Securities
               of such series in the amount above specified, as the case may
               be, may determine the time and the place in Houston, Texas, in
               The Borough of Manhattan, The City of New York, or in London,
               for such meeting and may call such meeting for such purposes by
               giving notice thereof as provided in subsection (a) of this
               Section 1302.

         SECTION 1303. Persons Entitled to Vote at Meetings.

         To be entitled to vote at any meeting of Holders of Securities of any
series, a Person shall be (1) a Holder of one or more Outstanding Securities of
such series, or (2) a Person appointed by an instrument in writing as proxy for
a Holder or Holders of one or more Outstanding Securities of such series by
such Holder or Holders. The only Persons who shall be entitled to be present or
to speak at any meeting of Holders of Securities of any series shall be the
Persons


                                     - 47 -

<PAGE>   57


entitled to vote at such meeting and their counsel, any representatives of the
Trustee and its counsel and any representatives of the Company and its counsel.

         SECTION 1304. Quorum; Action.

         The Persons entitled to vote a majority in aggregate principal amount
of the Outstanding Securities of a series shall constitute a quorum for a
meeting of Holders of Securities of such series. In the absence of a quorum
within 30 minutes of the time appointed for any such meeting, the meeting
shall, if convened at the request of Holders of Securities of such series, be
dissolved. In any other case, the meeting may be adjourned for a period of not
less than 10 days as determined by the chairman of the meeting prior to the
adjournment of such meeting. In the absence of a quorum at any such adjourned
meeting, such adjourned meeting may be further adjourned for a period of not
less than 10 days as determined by the chairman of the meeting prior to the
adjournment of such adjourned meeting. Subject to Section 1305(d), notice of
the reconvening of any adjourned meeting shall be given as provided in Section
1302(a), except that such notice need be given only once not less than five
days prior to the date on which the meeting is scheduled to be reconvened.
Notice of the reconvening of an adjourned meeting shall state expressly that
Persons entitled to vote a majority in principal amount of the Outstanding
Securities of such series shall constitute a quorum.

         Except as limited by the proviso to Section 902, any resolution
presented to a meeting or adjourned meeting duly reconvened at which a quorum
is present as aforesaid may be adopted by the affirmative vote of the Holders
of a majority in aggregate principal amount of the Outstanding Securities of
that series; provided, however, that, except as limited by the proviso to
Section 902, any resolution with respect to any request, demand, authorization,
direction, notice, consent or waiver which this Indenture expressly provides
may be made, given or taken by the Holders of a specified percentage that is
less than a majority in aggregate principal amount of the Outstanding
Securities of a series may be adopted at a meeting or an adjourned meeting duly
reconvened and at which a quorum is present as aforesaid by the affirmative
vote of the Holders of such specified percentage in aggregate principal amount
of the Outstanding Securities of that series.

         Except as limited by the proviso to Section 902, any resolution passed
or decision taken at any meeting of Holders of Securities of any series duly
held in accordance with this Section 1304 shall be binding on all the Holders
of Securities of such series, whether or not present or represented at the
meeting.

         SECTION 1305. Determination of Voting Rights; Conduct and Adjournment
                       of Meetings.

         (a)   The holding of Securities shall be proved in the manner
               specified in Section 105 and the appointment of any proxy shall
               be proved in the manner specified in Section 105. Such
               regulations may provide that written instruments appointing
               proxies, regular on their face, may be presumed valid and
               genuine without the proof specified in Section 105 or other
               proof.

         (b)   The Trustee shall, by an instrument in writing, appoint a
               temporary chairman of the meeting, unless the meeting shall have
               been called by the Company or by Holders of Securities as
               provided in Section 1302(b), in which case the Company or the
               Holders of Securities of the series calling the meeting, as the
               case may be, shall appoint a temporary chairman. A permanent
               chairman and a permanent secretary of the meeting shall be
               elected by vote of the Persons entitled to vote a majority in
               aggregate principal amount of the Outstanding Securities of such
               series represented at the meeting.

         (c)   At any meeting each Holder of a Security of such series and each
               proxy shall be entitled to one vote for each $1,000 principal
               amount of the Outstanding Securities of such series held or
               represented by him; provided, however, that no vote shall be
               cast or counted at any meeting in respect of any Security
               challenged as not Outstanding and ruled by the chairman of the
               meeting to be not Outstanding. The chairman of the meeting shall
               have no right to vote, except as a Holder of a Security of such
               series or as a proxy.


                                     - 48 -

<PAGE>   58


         (d)   Any meeting of Holders of Securities of any series duly called
               pursuant to Section 1302 at which a quorum is present may be
               adjourned from time to time by Persons entitled to vote a
               majority in aggregate principal amount of the Outstanding
               Securities of such series represented at the meeting; and the
               meeting may be held as so adjourned without further notice.

         SECTION 1306. Counting Votes and Recording Action of Meetings.

         The vote upon any resolution submitted to any meeting of Holders of
Securities of any series shall be by written ballots on which shall be
subscribed the signatures of the Holders of Securities of such series or of
their representatives by proxy and the principal amounts and serial numbers of
the Outstanding Securities of such series held or represented by them. The
permanent chairman of the meeting shall appoint two inspectors of votes who
shall count all votes cast at the meeting for or against any resolution and who
shall make and file with the secretary of the meeting their verified written
reports in duplicate of all votes cast at the meeting. A record, at least in
duplicate, of the proceedings of each meeting of Holders of Securities of any
series shall be prepared by the secretary of the meeting and there shall be
attached to such record the original reports of the inspectors of votes on any
vote by ballot taken thereat and affidavits by one or more persons having
knowledge of the facts setting forth a copy of the notice of the meeting and
showing that such notice was given as provided in Section 1302 and, if
applicable, Section 1304. Each copy shall be signed and verified by the
affidavits of the permanent chairman and secretary of the meeting and one such
copy shall be delivered to the Company, and another to the Trustee to be
preserved by the Trustee, the latter to have attached thereto the ballots voted
at the meeting. Any record so signed and verified shall be conclusive evidence
of the matters therein stated.

                                     * * *

         This instrument may be executed in any number of counterparts, each of
which so executed shall be deemed to be an original, but all such counterparts
shall together constitute but one and the same instrument.

         IN WITNESS WHEREOF, the parties hereto have caused this Indenture to
be duly executed, and their respective corporate seals to be hereunto affixed
and attested, all as of the day and year first above written.

                                   NOBLE DRILLING CORPORATION



[CORPORATE SEAL]                   By
                                     -------------------------------------
                                     Name:
                                          --------------------------------
                                     Title:
                                           -------------------------------


                                   CHASE BANK OF TEXAS, NATIONAL ASSOCIATION


[CORPORATE SEAL]                    By
                                      ------------------------------------
                                      Name:
                                           -------------------------------
                                      Title:
                                            ------------------------------




                                     - 49 -

<PAGE>   1

[Form of December __, 1998]                                        EXHIBIT 4.10
================================================================================









                           NOBLE DRILLING CORPORATION
                                     ISSUER



                                       AND

                    CHASE BANK OF TEXAS, NATIONAL ASSOCIATION
                                     TRUSTEE


                                 ---------------



                                    INDENTURE


                        DATED AS OF ______________, 199__



                                ----------------



                          SUBORDINATED DEBT SECURITIES
                              (ISSUABLE IN SERIES)







================================================================================


<PAGE>   2




                           NOBLE DRILLING CORPORATION

           RECONCILIATION AND TIE BETWEEN TRUST INDENTURE ACT OF 1939
                 AND INDENTURE, DATED AS OF ____________, 199__


<TABLE>
<CAPTION>

           Section of
         Trust Indenture                                                                    Section(s) of
           Act of 1939                                                                        Indenture
- ---------------------------------                                                    ---------------------------
<S>                      <C>                                                              <C>
(S) 310               (a)(1)........................................................      609
                      (a)(2)........................................................      609
                      (a)(3)........................................................      Not Applicable
                      (a)(4)........................................................      Not Applicable
                      (b)...........................................................      608, 610
(S) 311               (a)...........................................................      613
                      (b)...........................................................      613
                      (c)...........................................................      Not Applicable
(S) 312               (a)...........................................................      701, 702(a)
                      (b)...........................................................      702(b)
                      (c)...........................................................      702(b)
(S) 313               (a)...........................................................      703(a)
                      (b)...........................................................      703(a)
                      (c)...........................................................      703(a)
                      (d)...........................................................      703(b)
(S) 314               (a)...........................................................      704, 1005
                      (b)...........................................................      Not Applicable
                      (c)(1)........................................................      103
                      (c)(2)........................................................      103
                      (c)(3)........................................................      Not Applicable
                      (d)...........................................................      Not Applicable
                      (e)...........................................................      103
(S) 315               (a)...........................................................      601(a)
                      (b)...........................................................      602
                      (c)...........................................................      601(b)
                      (d)...........................................................      601(c)
                      (d)(1)........................................................      601(a)(1)
                      (d)(2)........................................................      601(c)(2)
                      (d)(3)........................................................      601(c)(3)
                      (e)...........................................................      514
(S) 316               (a)(1)(A).....................................................      502, 512
                      (a)(1)(B).....................................................      513
                      (a)(2)........................................................      Not Applicable
                      (a) last sentence.............................................      101
                      (b)...........................................................      508
(S) 317               (a)(1)........................................................      503
                      (a)(2)........................................................      504
                      (b)...........................................................      1003
(S) 318               (a)...........................................................      108
</TABLE>

- -------------
Note: This reconciliation and tie shall not, for any purpose, be deemed to be a
part of the Indenture.



                                       -i-

<PAGE>   3




                                TABLE OF CONTENTS

<TABLE>
<CAPTION>

                                                                                                              Page

<S>                                                                                                              <C>
ARTICLE ONE - DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION...........................................-1-
         SECTION 101.    Definitions............................................................................-1-
                  Act ..........................................................................................-1-
                  Additional Amounts............................................................................-1-
                  Affiliate.....................................................................................-2-
                  Agent Members.................................................................................-2-
                  Authenticating Agent..........................................................................-2-
                  Authorized Newspaper..........................................................................-2-
                  Board of Directors............................................................................-2-
                  Board Resolution..............................................................................-2-
                  Business Day..................................................................................-2-
                  Capital Stock.................................................................................-2-
                  Capitalized Lease Obligation..................................................................-2-
                  Commission....................................................................................-2-
                  Company  .....................................................................................-2-
                  Company Request...............................................................................-2-
                  Conversion Event..............................................................................-2-
                  Corporate Trust Office........................................................................-3-
                  Default  .....................................................................................-3-
                  Defaulted Interest............................................................................-3-
                  Depositary....................................................................................-3-
                  Designated Senior Indebtedness................................................................-3-
                  Disqualified Capital Stock....................................................................-3-
                  Dollar   .....................................................................................-3-
                  Event of Default..............................................................................-3-
                  Exchange Rate.................................................................................-3-
                  Holder   .....................................................................................-3-
                  Indebtedness..................................................................................-3-
                  Indenture.....................................................................................-4-
                  Interest .....................................................................................-4-
                  Interest Payment Date.........................................................................-4-
                  Interest Swap and Hedging Obligation..........................................................-4-
                  Judgment Currency.............................................................................-4-
                  Junior Security...............................................................................-4-
                  Maturity .....................................................................................-4-
                  Officers' Certificate.........................................................................-4-
                  Opinion of Counsel............................................................................-4-
                  Original Issue Discount Security..............................................................-4-
                  Outstanding...................................................................................-4-
                  Paying Agent..................................................................................-5-
                  Payment Default...............................................................................-5-
                  Payment Notice................................................................................-5-
                  Person   .....................................................................................-5-
                  Place of Payment..............................................................................-5-
                  Predecessor Security..........................................................................-5-
                  Qualified Capital Stock.......................................................................-5-
                  Redemption Date...............................................................................-5-
                  Redemption Price..............................................................................-5-
                  Regular Record Date...........................................................................-5-
                  Required Currency.............................................................................-6-
</TABLE>


                                      -ii-

<PAGE>   4


<TABLE>

<S>                                                                                                              <C>
                  Responsible Officer...........................................................................-6-
                  Securities....................................................................................-6-
                  Security Custodian............................................................................-6-
                  Security Register.............................................................................-6-
                  Senior Indebtedness...........................................................................-6-
                  Special Record Date...........................................................................-6-
                  Stated Maturity...............................................................................-6-
                  Subsidiary....................................................................................-6-
                  Trustee  .....................................................................................-6-
                  Trust Indenture Act...........................................................................-6-
                  United States.................................................................................-6-
                  United States Alien...........................................................................-7-
                  U.S. Government Obligations...................................................................-7-
                  Vice President................................................................................-7-
                  Wholly Owned Subsidiary.......................................................................-7-
                  Yield to Maturity.............................................................................-7-
         SECTION 102.   Incorporation by Reference of Trust Indenture Act.......................................-7-
         SECTION 103.   Compliance Certificates and Opinions....................................................-7-
         SECTION 104.   Form of Documents Delivered to Trustee..................................................-8-
         SECTION 105.   Acts of Holders; Record Dates...........................................................-8-
         SECTION 106.   Notices, Etc., to Trustee and Company...................................................-9-
         SECTION 107.   Notice to Holders; Waiver...............................................................-9-
         SECTION 108.   Conflict With Trust Indenture Act......................................................-10-
         SECTION 109.   Effect of Headings and Table of Contents...............................................-10-
         SECTION 110.   Successors and Assigns.................................................................-10-
         SECTION 111.   Separability Clause....................................................................-10-
         SECTION 112.   Benefits of Indenture..................................................................-10-
         SECTION 113.   Governing Law..........................................................................-10-
         SECTION 114.   Legal Holidays.........................................................................-10-
         SECTION 115.   Corporate Obligation...................................................................-11-

ARTICLE TWO - SECURITY FORMS...................................................................................-11-
         SECTION 201.   Forms Generally........................................................................-11-
         SECTION 202.   Form of Trustee's Certificate of Authentication........................................-11-
         SECTION 203.   Securities in Global Form..............................................................-11-

ARTICLE THREE - THE SECURITIES.................................................................................-13-
         SECTION 301.   Amount Unlimited; Issuable in Series...................................................-13-
         SECTION 302.   Denominations..........................................................................-16-
         SECTION 303.   Execution, Authentication, Delivery and Dating.........................................-16-
         SECTION 304.   Temporary Securities...................................................................-17-
         SECTION 305.   Registration, Registration of Transfer and Exchange....................................-17-
         SECTION 306.   Mutilated, Destroyed, Lost and Stolen Securities.......................................-18-
         SECTION 307.   Payment of Interest; Interest Rights Preserved.........................................-18-
         SECTION 308.   Persons Deemed Owners..................................................................-19-
         SECTION 309.   Cancellation...........................................................................-19-
         SECTION 310.   Computation of Interest................................................................-20-
         SECTION 311.   CUSIP Numbers..........................................................................-20-

ARTICLE FOUR - SATISFACTION AND DISCHARGE......................................................................-20-
         SECTION 401.   Satisfaction and Discharge of Indenture................................................-20-
         SECTION 402.   Application of Trust Money.............................................................-21-
         SECTION 403.   Discharge of Liability on Securities of Any Series.....................................-21-
         SECTION 404.   Reinstatement..........................................................................-22-
</TABLE>


                                      -iii-

<PAGE>   5


<TABLE>


<S>                                                                                                            <C>
ARTICLE FIVE - REMEDIES .......................................................................................-22-
         SECTION 501.   Events of Default .....................................................................-22-
         SECTION 502.   Acceleration of Maturity; Rescission and Annulment.....................................-23-
         SECTION 503.   Collection of Indebtedness and Suits for Enforcement by Trustee........................-24-
         SECTION 504.   Trustee May File Proofs of Claim.......................................................-25-
         SECTION 505.   Trustee May Enforce Claims Without Possession of Securities or Coupons.................-25-
         SECTION 506.   Application of Money Collected.........................................................-26-
         SECTION 507.   Limitation on Suits....................................................................-26-
         SECTION 508.   Unconditional Right of Holders to Receive Principal, Premium and Interest..............-27-
         SECTION 509.   Restoration of Rights and Remedies.....................................................-27-
         SECTION 510.   Rights and Remedies Cumulative.........................................................-27-
         SECTION 511.   Delay or Omission Not Waiver...........................................................-27-
         SECTION 512.   Control by Holders.....................................................................-27-
         SECTION 513.   Waiver of Past Defaults................................................................-28-
         SECTION 514.   Undertaking for Costs..................................................................-28-
         SECTION 515.   Waiver of Stay or Extension Laws.......................................................-28-

ARTICLE SIX - THE TRUSTEE......................................................................................-28-
         SECTION 601.   Certain Duties and Responsibilities....................................................-28-
         SECTION 602.   Notice of Defaults.....................................................................-29-
         SECTION 603.   Certain Rights of Trustee..............................................................-30-
         SECTION 604.   Not Responsible for Recitals or Issuance of Securities.................................-31-
         SECTION 605.   May Hold Securities....................................................................-31-
         SECTION 606.   Money Held in Trust....................................................................-31-
         SECTION 607.   Compensation and Reimbursement.........................................................-31-
         SECTION 608.   Disqualification; Conflicting Interests................................................-32-
         SECTION 609.   Corporate Trustee Required; Eligibility................................................-32-
         SECTION 610.   Resignation and Removal; Appointment of Successor......................................-32-
         SECTION 611.   Acceptance of Appointment by Successor.................................................-33-
         SECTION 612.   Merger, Conversion, Consolidation or Succession to Business............................-34-
         SECTION 613.   Preferential Collection of Claims Against Company......................................-34-
         SECTION 614.   Appointment of Authenticating Agent....................................................-34-

ARTICLE SEVEN - HOLDER'S LISTS AND REPORTS BY TRUSTEE AND COMPANY .............................................-35-
         SECTION 701.   Company to Furnish Trustee Names and Addresses of Holders..............................-35-
         SECTION 702.   Preservation of Information; Communications to Holders.................................-36-
         SECTION 703.   Reports by Trustee.....................................................................-36-
         SECTION 704.   Reports by Company.....................................................................-36-

ARTICLE EIGHT - CONSOLIDATION, MERGER, CONVEYANCE, TRANSFER OR LEASE ..........................................-36-
         SECTION 801.   Company May Consolidate, Etc., Only on Certain Terms...................................-36-
         SECTION 802.   Successor Person Substituted...........................................................-37-

ARTICLE NINE - SUPPLEMENTAL INDENTURES.........................................................................-37-
         SECTION 901.   Supplemental Indentures Without Consent of Holders.....................................-37-
         SECTION 902.   Supplemental Indentures With Consent of Holders........................................-38-
         SECTION 903.   Execution of Supplemental Indentures...................................................-39-
         SECTION 904.   Effect of Supplemental Indentures......................................................-39-
         SECTION 905.   Conformity With Trust Indenture Act....................................................-39-
         SECTION 906.   Reference in Securities to Supplemental Indentures.....................................-39-

ARTICLE TEN - COVENANTS........................................................................................-39-
         SECTION 1001.  Payment of Principal, Premium and Interest.............................................-39-
         SECTION 1002.  Maintenance of Office or Agency........................................................-39-
         SECTION 1003.  Money for Securities Payments to be Held in Trust......................................-40-
</TABLE>

                                      -iv-

<PAGE>   6


<TABLE>

<S>                                                                                                             <C>
         SECTION 1004.  Existence..............................................................................-41-
         SECTION 1005.  Statement by Officers as to Default....................................................-41-
         SECTION 1006.  Waiver of Certain Covenants............................................................-41-
         SECTION 1007.  Additional Amounts.....................................................................-41-

ARTICLE ELEVEN - REDEMPTION OF SECURITIES......................................................................-42-
         SECTION 1101.  Applicability of Article...............................................................-42-
         SECTION 1102.  Election to Redeem; Notice to Trustee..................................................-42-
         SECTION 1103.  Selection by Trustee of Securities to be Redeemed......................................-42-
         SECTION 1104.  Notice of Redemption...................................................................-42-
         SECTION 1105.  Deposit of Redemption Price............................................................-43-
         SECTION 1106.  Securities Payable on Redemption Date..................................................-43-
         SECTION 1107.  Securities Redeemed in Part............................................................-43-

ARTICLE TWELVE - SINKING FUNDS.................................................................................-44-
         SECTION 1201.  Applicability of Article...............................................................-44-
         SECTION 1202.  Satisfaction of Sinking Fund Payments with Securities..................................-44-
         SECTION 1203.  Redemption of Securities for Sinking Fund..............................................-44-

ARTICLE THIRTEEN - SUBORDINATION...............................................................................-44-
         SECTION 1301.  Securities Subordinated to Senior Indebtedness.........................................-44-
         SECTION 1302.  No Payment on Securities in Certain Circumstances......................................-45-
         SECTION 1303.  Securities Subordinated to Prior Payment of All Senior.................................-45-
         SECTION 1304.  Subrogation to Rights of Holders of Senior Indebtedness................................-46-
         SECTION 1305.  Obligations of the Company Unconditional...............................................-47-
         SECTION 1306.  Trustee Entitled to Assume Payments Not Prohibited in Absence of Notice................-47-
         SECTION 1307.  Application by Trustee of Amounts Deposited with It....................................-47-
         SECTION 1308.  Subordination Rights Not Impaired by Acts or Omissions of the Company or
                        Holders of Senior Indebtedness.........................................................-47-
         SECTION 1309.  Trustee to Effectuate Subordination of Securities......................................-48-
         SECTION 1310.  Right of Trustee to Hold Senior Indebtedness...........................................-48-
         SECTION 1311.  Article Thirteen Not to Prevent Events of Default......................................-48-
         SECTION 1312.  No Fiduciary Duty of Trustee to Holders of Senior Indebtedness.........................-48-
         SECTION 1313.  Article Applicable to Paying Agent.....................................................-48-

ARTICLE FOURTEEN - MEETINGS OF HOLDERS OF SECURITIES...........................................................-49-
         SECTION 1401.  Purposes for Which Meetings May Be Called..............................................-49-
         SECTION 1402.  Call, Notice and Place of Meetings.....................................................-49-
         SECTION 1403.  Persons Entitled to Vote at Meetings...................................................-49-
         SECTION 1404.  Quorum;  Action........................................................................-49-
         SECTION 1405.  Determination of Voting Rights; Conduct and Adjournment of Meetings....................-50-
         SECTION 1406.  Counting Votes and Recording Action of Meetings........................................-50-
</TABLE>


                                       -v-

<PAGE>   7




         INDENTURE, dated as of ____________, 199___ between NOBLE DRILLING
CORPORATION, a corporation duly organized and existing under the laws of the
State of Delaware (herein called the "Company"), having its principal office at
10370 Richmond Avenue, Suite 400, Houston, Texas 77042, and CHASE BANK OF TEXAS,
NATIONAL ASSOCIATION, a national banking association duly organized and existing
under the laws of the United States of America, as Trustee (herein called the
"Trustee"), the office of the Trustee at which at the date hereof its corporate
trust business is principally administered being 600 Travis, Suite 1150,
Houston, Texas 77002, Attention: Global Trust Service Department.

                             RECITALS OF THE COMPANY

         The Company has duly authorized the execution and delivery of this
Indenture to provide for the issuance from time to time of its unsecured
subordinated debentures, notes or other evidences of indebtedness (herein called
the "Securities"), to be issued in one or more series as provided in this
Indenture.

         This Indenture is subject to the provisions of the Trust Indenture Act
and the rules and regulations of the Commission promulgated thereunder that are
required to be part of this Indenture and, to the extent applicable, shall be
governed by such provisions.

         All things necessary to make this Indenture a valid agreement of the
Company, in accordance with its terms, have been done.

         NOW, THEREFORE, THIS INDENTURE WITNESSETH:

         For and in consideration of the premises and the purchase of the
Securities by the Holders thereof, it is mutually covenanted and agreed, for the
equal and proportionate benefit of all Holders of the Securities or of series
thereof, as follows:

                                   ARTICLE ONE

                        DEFINITIONS AND OTHER PROVISIONS
                             OF GENERAL APPLICATION

SECTION 101.               Definitions.

         For all purposes of this Indenture, except as otherwise expressly
provided or unless the context otherwise requires:

                  (1) the terms defined in this Article One have the meanings
         assigned to them in this Article One and include the plural as well as
         the singular;

                  (2) all accounting terms not otherwise defined herein have the
         meanings assigned to them in accordance with generally accepted
         accounting principles in the United States, and, except as otherwise
         herein expressly provided, the term "generally accepted accounting
         principles" with respect to any computation required or permitted
         hereunder shall mean such accounting principles as are generally
         accepted in the United States at the date of such computation; and

                  (3) the words "herein," "hereof" and "hereunder" and other
         words of similar import refer to this Indenture as a whole and not to
         any particular Article, Section or other subdivision.

         Certain terms, used principally in Article Six, are defined in Section
102.

         "Act," when used with respect to any Holder, has the meaning specified
in Section 105.

         "Additional Amounts" means any additional amounts that are required by
the express terms of a Security or by or pursuant to a Board Resolution, under
circumstances specified therein or pursuant thereto, to be paid by the 

                                       -1-

<PAGE>   8



Company with respect to certain taxes, assessments or other governmental charges
imposed on certain Holders and that are owing to such Holders.

         "Affiliate" of any specified Person means any other Person directly or
indirectly controlling or controlled by or under direct or indirect common
control with such specified Person. For the purposes of this definition,
"control" when used with respect to any specified Person means the power to
direct the management and policies of such Person, directly or indirectly,
whether through the ownership of voting securities, by contract or otherwise;
and the terms "controlling" and "controlled" have meanings correlative to the
foregoing.

         "Agent Members" has the meaning specified in Section 203.

         "Authenticating Agent" means any Person, which may include the Company,
authorized by the Trustee to act on behalf of the Trustee pursuant to Section
614 to authenticate Securities of one or more series.

         "Authorized Newspaper" means a newspaper, in the English language or in
an official language of the country of publication, customarily published on
each Business Day, whether or not published on Saturdays, Sundays or holidays,
and of general circulation in the place in connection with which the term is
used or in the financial community of such place. Where successive publications
are required to be made in Authorized Newspapers, the successive publications
may be made in the same or in different newspapers in the same city meeting the
foregoing requirements and in each case on any Business Day.

         "Board of Directors" means either the board of directors of the Company
or any duly authorized committee of that board.

         "Board Resolution" means a copy of a resolution certified by the
Secretary or an Assistant Secretary of the Company to have been duly adopted by
the Board of Directors and to be in full force and effect on the date of such
certification, and delivered to the Trustee.

         "Business Day," when used with respect to any Place of Payment, means
each Monday, Tuesday, Wednesday, Thursday and Friday that is not a day on which
banking institutions in that Place of Payment or the city in which the Corporate
Trust Office is located are authorized or obligated by law or executive order to
close.

         "Capital Stock" means, with respect to any Person, any and all shares,
interests, rights to purchase (other than convertible or exchangeable
Indebtedness), warrants, options, participations or other equivalents of or
interests (however designated) in stock issued by that Person.

         "Capitalized Lease Obligation" means rental obligations under a lease
that are required to be capitalized for financial reporting purposes in
accordance with generally accepted accounting principles, and the amount of
Indebtedness represented by such obligations shall be the capitalized amount of
such obligations, as determined in accordance with generally accepted accounting
principles.

         "Commission" means the Securities and Exchange Commission, as from time
to time constituted, created under the Securities Exchange Act of 1934, as
amended, or, if at any time after the execution of this instrument such
Commission is not existing and performing the duties now assigned to it under
the Trust Indenture Act, then the body performing such duties at such time.

         "Company" means the Person named as the "Company" in the first
paragraph of this instrument until a successor Person shall have become such
pursuant to the applicable provisions of this Indenture, and thereafter
"Company" shall mean such successor Person.

         "Company Request" and "Company Order" mean, respectively, a written
request or order signed in the name of the Company by its Chairman of the Board,
its President or a Vice President, and by its Treasurer, an Assistant Treasurer,
its Controller, an Assistant Controller, its Secretary or an Assistant
Secretary, and delivered to the Trustee.

         "Conversion Event" has the meaning specified in Section 501.


                                       -2-

<PAGE>   9




         "Corporate Trust Office" means the principal office of the Trustee in
Houston, Texas at which at any particular time its corporate trust business
shall be principally administered, which office at the date hereof is that
indicated in the introductory paragraph of this Indenture.

         "Default" means, with respect to the Securities of any series, any
event, act or condition that is, or after notice or the passage of time or both
would be, an Event of Default with respect to Securities of such series.

         "Defaulted Interest" has the meaning specified in Section 307.

         "Depositary" means, with respect to the Securities of any series
issuable or issued in whole or in part in a global form, the Person designated
as Depositary by the Company pursuant to Section 301 with respect to the
Securities of such series, until a successor Depositary shall have become such
pursuant to the applicable provisions of this Indenture, and thereafter
"Depositary" shall mean or include each Person who is then a Depositary
hereunder, and if at any time there is more than one such person, "Depositary"
as used with respect to the Securities of any series shall mean the Depositary
with respect to the Securities of that series.

         "Designated Senior Indebtedness," unless otherwise provided with
respect to the Securities of a series as contemplated by Section 301, means any
Senior Indebtedness that (i) in the instrument evidencing the same or the
assumption or guarantee thereof (or related documents to which the Company is a
party) is expressly designated as "Designated Senior Indebtedness" for purposes
of this Indenture and (ii) satisfies such other conditions as may be provided
with respect to the Securities of such series; provided that such instruments or
documents may place limitations and conditions on the right of such Senior
Indebtedness to exercise the rights of Designated Senior Indebtedness.

         "Disqualified Capital Stock" means, when used with respect to the
Securities of any series, (a) with respect to any Person, Capital Stock of such
Person that, by its terms or by the terms of any security into which it is
convertible, exercisable or exchangeable, is, or upon the happening of an event
or the passage of time would be, required to be redeemed or repurchased
(including at the option of the holder thereof) by such Person or any Subsidiary
of such Person, in whole or in part, on or prior to the Stated Maturity of the
Securities of such series, and (b) with respect to any Subsidiary of such Person
(including with respect to any Subsidiary of the Company), any Capital Stock
other than any common stock with no preference, privileges, or redemption or
repayment provisions.

         "Dollar" or "$" means a dollar or other equivalent unit in such coin or
currency of the United States as at the time shall be legal tender for the
payment of public and private debts.

         "Event of Default" has the meaning specified in Section 501.

         "Exchange Rate" has the meaning specified in Section 302.

         "Holder," when used with respect to any Security, means the Person in
whose name the Security is registered in the Security Register.

         "Indebtedness" of any Person, unless otherwise provided with respect to
the Securities of a series as contemplated by Section 301, means, without
duplication, the following (whether currently outstanding or hereafter incurred
or created): (i) all liabilities and obligations, contingent or otherwise, of
any such Person (a) in respect of borrowed money (whether or not the recourse of
the lender is to the whole of the assets of such Person or only to a portion
thereof), (b) evidenced by bonds, notes, debentures or similar instruments, (c)
representing the balance deferred and unpaid of the purchase price of any
property or services, except such as would constitute trade payables to trade
creditors in the ordinary course of business that are not more than 90 days past
their original due date, (d) evidenced by bankers' acceptances or similar
instruments issued or accepted by banks, (e) for the payment of money relating
to a Capitalized Lease Obligation or (f) evidenced by a letter of credit or a
reimbursement obligation of such Person with respect to any letter of credit;
(ii) all net obligations of such Person under Interest Swap and Hedging
Obligations; (iii) all liabilities of others of the kind described in the
preceding clause (i) or (ii) that such Person has guaranteed or that is
otherwise its legal liability and all obligations to purchase, redeem or acquire
any Capital Stock; and (iv) any and all deferrals, renewals, extensions,
refinancings, refundings (whether direct or indirect) of, or amendments,
modifications 


                                       -3-

<PAGE>   10


or supplements to, any liability of the kind described in any of the preceding
clauses (i), (ii) or (iii), or this clause (iv), whether or not between or among
the same parties.

         "Indenture" means this instrument as originally executed or as it may
from time to time be supplemented or amended by one or more indentures
supplemental hereto entered into pursuant to the applicable provisions hereof
and shall include the terms of particular series of Securities established as
contemplated by Section 301 and the provisions of the Trust Indenture Act that
are deemed to be a part of and govern this instrument.

         "Interest," when used with respect to an Original Issue Discount
Security that by its terms bears interest only after Maturity, means interest
payable after Maturity.

         "Interest Payment Date," when used with respect to any Security, means
the Stated Maturity of an installment of interest on such Security.

         "Interest Swap and Hedging Obligation" means any obligation of any
Person pursuant to any interest rate swap agreement, interest rate cap
agreement, interest rate collar agreement, interest rate exchange agreement,
currency exchange agreement or any other agreement or arrangement designed to
protect against fluctuations in interest rates or currency values, including,
without limitation, any arrangement whereby, directly or indirectly, such Person
is entitled to receive from time to time periodic payments calculated by
applying either a fixed or floating rate of interest on a stated notional amount
in exchange for periodic payments made by such Person calculated by applying a
fixed or floating rate of interest on the same notional amount.

         "Judgment Currency" has the meaning specified in Section 506.

         "Junior Security" of a Person means, when used with respect to the
Securities of any series, any Qualified Capital Stock of such Person or any
Indebtedness of such Person that is subordinated in right of payment to the
Securities of such series and has no scheduled installment of principal due, by
redemption, sinking fund payment or otherwise, on or prior to the Stated
Maturity of the Securities of such series.

         "Maturity," when used with respect to any Security, means the date on
which the principal of such Security or an installment of principal becomes due
and payable as therein or herein provided, whether at the Stated Maturity or by
declaration of acceleration, call for redemption or otherwise.

         "Officers' Certificate" means a certificate signed by the Chairman of
the Board, the President or a Vice President, and by the Treasurer, the
Controller, the Secretary or an Assistant Treasurer, Assistant Controller or
Assistant Secretary of the Company, and delivered to the Trustee, which
certificate shall be in compliance with Section 103 hereof.

         "Opinion of Counsel" means a written opinion of counsel, who may be
counsel for or an employee of the Company, rendered, if applicable, in
accordance with Section 314(c) of the Trust Indenture Act, which opinion shall
be in compliance with Section 103 hereof.

         "Original Issue Discount Security" means any Security that provides for
an amount less than the principal amount thereof to be due and payable upon a
declaration of acceleration of the Maturity thereof pursuant to Section 502.

         "Outstanding," when used with respect to Securities of a series, means
as of the date of determination, all Securities of such series theretofore
authenticated and delivered under this Indenture, except:

                  (i) Securities theretofore canceled by the Trustee or
         delivered to the Trustee for cancellation;

                  (ii) Securities for whose payment or redemption money in the
         necessary amount has been theretofore irrevocably deposited with the
         Trustee or any Paying Agent (other than the Company) in trust or set
         aside and segregated in trust by the Company (if the Company shall act
         as its own Paying Agent) for the Holders of such Securities; provided
         that, if such Securities are to be redeemed, notice of such redemption
         has been duly given pursuant to this Indenture or provision therefor
         satisfactory to the Trustee has been made; and


                                      -4-
<PAGE>   11


                  (iii) Securities that have been paid pursuant to Section 306
         or in exchange for or in lieu of which other Securities have been
         authenticated and delivered pursuant to this Indenture, other than any
         such Securities in respect of which there shall have been presented to
         the Trustee proof satisfactory to it that such Securities are held by a
         bona fide purchaser in whose hands such Securities are valid
         obligations of the Company; provided, however, that in determining
         whether the Holders of the requisite principal amount of the
         Outstanding Securities have given any request, demand, authorization,
         direction, notice, consent or waiver hereunder, or whether a quorum is
         present at a meeting of Holders of Securities, (a) the principal amount
         of an Original Issue Discount Security that shall be deemed to be
         Outstanding for such purposes shall be the principal amount thereof
         that would be due and payable as of the date of such determination upon
         acceleration of the Maturity thereof pursuant to Section 502, (b) the
         principal amount of a Security denominated in a foreign currency shall
         be the U.S. dollar equivalent, determined by the Company on the date of
         original issuance of such Security, of the principal amount (or, in the
         case of an Original Issue Discount Security, the U.S. dollar
         equivalent, determined on the date of original issuance of such
         Security, of the amount determined as provided in (a) above), of such
         Security and (c) Securities owned by the Company or any other obligor
         upon the Securities or any Affiliate of the Company or of such other
         obligor shall be disregarded and deemed not to be Outstanding, except
         that, in determining whether the Trustee shall be protected in relying
         upon any such request, demand, authorization, direction, notice,
         consent or waiver or upon any such determination as to the presence of
         a quorum, only Securities which a Responsible Officer of the Trustee
         knows to be so owned shall be so disregarded. Securities so owned which
         have been pledged in good faith may be regarded as Outstanding if the
         pledgee establishes to the satisfaction of the Trustee the pledgee's
         right so to act with respect to such Securities and that the pledgee is
         not the Company or any other obligor upon the Securities or any
         Affiliate of the Company or of such other obligor.

         "Paying Agent" means any Person, which may include the Company,
authorized by the Company to pay the principal of, premium (if any) or interest
on or any Additional Amounts with respect to any one or more series of
Securities on behalf of the Company.

         "Payment Default" has the meaning specified in Section 1302(a).

         "Payment Notice" has the meaning specified in Section 1302(b).

         "Person" means any individual, corporation, partnership, limited
liability company, joint venture, incorporated or unincorporated association,
joint-stock company, trust, unincorporated organization or government or other
agency or political subdivision thereof or other entity of any kind.

         "Place of Payment," when used with respect to the Securities of any
series, means the place or places where the principal of, premium (if any) or
interest on or any Additional Amounts with respect to the Securities of such
series are payable as specified in accordance with Section 301 subject to the
provisions of Section 1002.

         "Predecessor Security" of any particular Security means every previous
Security evidencing all or a portion of the same debt as that evidenced by such
particular Security; and, for the purposes of this definition, any Security
authenticated and delivered under Section 306 in exchange for or in lieu of a
mutilated, destroyed, lost or stolen Security shall be deemed to evidence the
same debt as the mutilated, destroyed, lost or stolen Security.

         "Qualified Capital Stock" means any Capital Stock of the Company that
is not Disqualified Capital Stock.

         "Redemption Date," when used with respect to any Security to be
redeemed, means the date fixed for such redemption by or pursuant to the terms
of such Security and this Indenture.

         "Redemption Price," when used with respect to any Security to be
redeemed, means the price at which it is to be redeemed pursuant to the terms of
such Security and this Indenture.

         "Regular Record Date" for the interest payable on any Interest Payment
Date on the Securities of any series means the date specified for that purpose
as contemplated by Section 301, or, if not so specified, the last day of the
calendar month preceding such Interest Payment Date if such Interest Payment
Date is the fifteenth day of the calendar month or the fifteenth day of the
calendar

                                      -5-

<PAGE>   12

month preceding such Interest Payment Date if such Interest Payment Date is the
first day of a calendar month, whether or not such day shall be a Business Day.

         "Required Currency" has the meaning specified in Section 506.

         "Responsible Officer," when used with respect to the Trustee, means any
officer of the Trustee with direct responsibility for the administration of this
Indenture and also means, with respect to a particular corporate trust matter,
any other officer to whom such matter is referred because of his knowledge of
and familiarity with the particular subject.

         "Securities" has the meaning stated in the first recital of this
Indenture and more particularly means any Securities authenticated and delivered
under this Indenture.

         "Security Custodian" means, with respect to Securities of a series
issued in global form, the Trustee for Securities of such series, acting in its
capacity as custodian with respect to the Securities of such series, or any
successor entity thereto.

         "Security Register" and "Security Registrar" have the respective
meanings specified in Section 305.

         "Senior Indebtedness" of the Company, unless otherwise provided with
respect to the Securities of a series as contemplated by Section 301, means (i)
all Indebtedness of the Company, whether currently outstanding or hereafter
issued, unless, by the terms of the instrument creating or evidencing such
Indebtedness, it is provided that such Indebtedness is not superior in right of
payment to the Securities or to other Indebtedness which is pari passu with or
subordinated to the Securities, and (ii) any modifications, refunding,
deferrals, renewals or extensions of any such Indebtedness or securities, notes
or other evidences of Indebtedness issued in exchange for such Indebtedness;
provided that in no event shall "Senior Indebtedness" include (a) Indebtedness
of the Company owed or owing to any Subsidiary of the Company or any officer,
director or employee of the Company or any Subsidiary of the Company, (b)
Indebtedness to trade creditors or (c) any liability for taxes owed or owing by
the Company.

         "Special Record Date" for the payment of any Defaulted Interest on the
Securities of any series means a date fixed by the Trustee pursuant to Section
307.

         "Stated Maturity," when used with respect to any Security or any
installment of principal thereof or interest thereon, means the date specified
in such Security as the fixed date on which the principal of such Security or
such installment of principal or interest is due and payable.

         "Subsidiary" means, as to any Person, a corporation more than 50% of
the outstanding voting stock of which is owned, directly or indirectly, by such
Person or by one or more other Subsidiaries of such Person, or by such Person
and one or more other Subsidiaries of such Person. For the purposes of this
definition, "voting stock" means stock that ordinarily has voting power for the
election of directors, whether at all times or only so long as no senior class
of stock has such voting power by reason of any contingency.

         "Trustee" means the Person named as the "Trustee" in the first
paragraph of this instrument until a successor Trustee shall have become such
pursuant to the applicable provisions of this Indenture, and thereafter
"Trustee" shall mean or include each Person who is then a Trustee hereunder, and
if at any time there is more than one such Person, "Trustee" as used with
respect to the Securities of any series shall mean the Trustee with respect to
Securities of that series.

         "Trust Indenture Act" means the Trust Indenture Act of 1939 as in force
at the date as of which this instrument was executed, except as provided in
Section 905; provided, however, that, in the event the Trust Indenture Act of
1939 is amended after such date, "Trust Indenture Act" means, to the extent
required by any such amendment, the Trust Indenture Act of 1939 as so amended.

         "United States" means the United States of America (including the
States and the District of Columbia) and its "possessions," which include Puerto
Rico, the U.S. Virgin Islands, Guam, American Samoa, Wake Island and the
Northern Mariana Islands.


                                      -6-
<PAGE>   13


         "United States Alien" means any Person who, for United States federal
income tax purposes, is a foreign corporation, a nonresident alien individual, a
nonresident alien or foreign fiduciary of an estate or trust, or a foreign
partnership.

         "U.S. Government Obligations" has the meaning specified in Section 401.

         "Vice President," when used with respect to the Company or the Trustee,
means any vice president, whether or not designated by a number or a word or
words added before or after the title "vice president".

         "Wholly Owned Subsidiary" means, as to any Person, a corporation all
the outstanding voting stock (other than any directors' qualifying shares) of
which is owned, directly or indirectly, by such Person or by one or more other
Wholly Owned Subsidiaries of such Person, or by such Person and one or more
other Wholly Owned Subsidiaries of such Person. For the purposes of this
definition, "voting stock" means stock which ordinarily has voting power for the
election of directors, whether at all times or only so long as no senior class
of stock has such voting power by reason of any contingency.

         "Yield to Maturity," when used with respect to any Original Issue
Discount Security, means the yield to maturity, if any, set forth on the face
thereof.

SECTION 102.    Incorporation by Reference of Trust Indenture Act.

         Whenever this Indenture refers to a provision of the Trust Indenture
Act, the provision is incorporated by reference in and made a part of this
Indenture. The following Trust Indenture Act terms used in this Indenture have
the following meanings:

         "Bankruptcy Act" means the Bankruptcy Act or Title 11 of the United
States Code.

         "indenture securities" means the Securities.

         "indenture security holder" means a Holder.

         "indenture to be qualified" means this Indenture.

         "indenture trustee" or "institutional trustee" means the Trustee.

         "obligor" on the indenture securities means the Company or any other
obligor on the Securities.

         All terms used in this Indenture that are defined by the Trust
Indenture Act, defined by a Trust Indenture Act reference to another statute or
defined by Commission rule under the Trust Indenture Act and not otherwise
defined herein have the meanings assigned to them therein.

SECTION 103.   Compliance Certificates and Opinions.

         Except as otherwise expressly provided by this Indenture, upon any
application or request by the Company to the Trustee to take any action under
any provision of this Indenture, the Company shall furnish to the Trustee an
Officers' Certificate stating that all conditions precedent, if any, provided
for in this Indenture relating to the proposed action have been complied with
and an Opinion of Counsel stating that in the opinion of such counsel all such
conditions precedent, if any, have been complied with, except that in the case
of any such application or request as to which the furnishing of such documents
is specifically required by any provision of this Indenture relating to such
particular application or request, no additional certificate or opinion need be
furnished.

         Every certificate or opinion with respect to compliance with a
condition or covenant provided for in this Indenture shall include


                                      -7-
<PAGE>   14


                  (1) a statement that each Person signing such certificate or
         opinion has read such covenant or condition and the definitions herein
         relating thereto;

                  (2) a brief statement as to the nature and scope of the
         examination or investigation upon which the statements or opinions
         contained in such certificate or opinion are based;

                  (3) a statement that, in the opinion of each such Person, such
         Person has made such examination or investigation as is necessary to
         enable such Person to express an informed opinion as to whether or not
         such covenant or condition has been complied with; and

                  (4) a statement as to whether, in the opinion of each such
         Person, such condition or covenant has been complied with.

SECTION 104.    Form of Documents Delivered to Trustee.

         In any case where several matters are required to be certified by, or
covered by an opinion of, any specified Person, it is not necessary that all
such matters be certified by, or covered by the opinion of, only one such
Person, or that they be so certified or covered by only one document, but one
such Person may certify or give an opinion with respect to some matters and one
or more other such Persons as to other matters, and any such Person may certify
or give an opinion as to such matters in one or several documents.

         Any certificate or opinion of an officer of the Company may be based,
insofar as it relates to legal matters, upon a certificate or opinion of, or
representations by, counsel, unless such officer knows, or in the exercise of
reasonable care should know, that the certificate or opinion or representations
with respect to the matters upon which his certificate or opinion is based are
erroneous. Any such certificate or Opinion of Counsel may be based, insofar as
it relates to factual matters, upon a certificate or opinion of, or
representations by, an officer or officers of the Company stating that the
information with respect to such factual matters is in the possession of the
Company, unless such counsel knows, or in the exercise of reasonable care should
know, that the certificate or opinion or representations with respect to such
matters are erroneous.

         Where any Person is required to make, give or execute two or more
applications, requests, consents, certificates, statements, opinions or other
instruments under this Indenture, they may, but need not, be consolidated and
form one instrument.

SECTION 105.    Acts of Holders; Record Dates.

         (a) Any request, demand, authorization, direction, notice, consent,
waiver or other action provided by this Indenture to be given or taken by
Holders may be embodied in and evidenced by one or more instruments of
substantially similar tenor signed by such Holders in person or by an agent duly
appointed in writing. Except as herein otherwise expressly provided, such action
shall become effective when such instrument or instruments or record or both are
delivered to the Trustee and, where it is hereby expressly required, to the
Company. Such instrument or instruments and any such record (and the action
embodied therein and evidenced thereby) are herein sometimes referred to as the
"Act" of the Holders signing such instrument or instruments and so voting at any
such meeting. Proof of execution of any such instrument or of a writing
appointing any such agent, or the holding of any Person of a Security, shall be
sufficient for any purpose of this Indenture and (subject to Section 601)
conclusive in favor of the Trustee and the Company, if made in the manner
provided in this Section 105. The record of any meeting of Holders of Securities
shall be proved in the manner provided in Section 1406.

         The Company may set a record date for purposes of determining the
identity of Holders of Securities entitled to vote or consent to any action by
vote or consent authorized or permitted under this Indenture. If a record date
is fixed, those Persons who were Holders of Outstanding Securities at such
record date (or their duly designated proxies), and only those Persons, shall be
entitled with respect to such Securities to take such action by vote or consent
or to revoke any vote or consent previously given, whether or not such Persons
continue to be Holders after such record date. Promptly after any record date is
set pursuant to this paragraph, the Company, at its own expense, shall cause
notice



                                      -8-
<PAGE>   15



thereof to be given to the Trustee in writing in the manner provided in Section
106 and to the relevant Holders as set forth in Section 107.

         (b) The fact and date of the execution by any Person of any such
instrument or writing may be proved by the affidavit of a witness of such
execution or by a certificate of a notary public or other officer authorized by
law to take acknowledgments of deeds, certifying that the individual signing
such instrument or writing acknowledged to him the execution thereof. Where such
execution is by a signer acting in a capacity other than his individual
capacity, such certificate or affidavit shall also constitute sufficient proof
of his authority. The fact and date of the execution of any such instrument or
writing, or the authority of the Person executing the same, may also be proved
in any other manner which the Trustee deems sufficient.

         (c) The principal amount and serial numbers of Securities held by any
Person, and the date of holding the same, shall be proved by the Security
Register.

         (d) In determining whether the Holders of the requisite principal
amount of Securities have given any request, demand, authorization, direction,
notice, consent or waiver under this Indenture, the principal amount of an
Original Issue Discount Security that may be counted in making such
determination and that shall be deemed to be Outstanding for such purposes shall
be equal to the amount of the principal thereof that would be due and payable
upon a declaration of acceleration of the Maturity thereof pursuant to Section
502 at the time the taking of such action by the Holders of such requisite
principal amount is evidenced to the Trustee for such Securities.

         (e) Any request, demand, authorization, direction, notice, consent,
waiver or other Act of the Holder of any Security shall bind every future Holder
of the same Security and the Holder of every Security issued upon the
registration of transfer thereof or in exchange therefor or in lieu thereof in
respect of anything done, omitted or suffered to be done by the Trustee or the
Company in reliance thereon, whether or not notation of such action is made upon
such Security. Any consent or waiver of the Holder of any Security shall be
irrevocable for a period of six months after the date of execution thereof, but
otherwise any such Holder or subsequent Holder may revoke the request, demand,
authorization, direction, notice, consent or other Act as to his Security or
portion of his Security; provided, however, that such revocation shall be
effective only if the Trustee receives the notice of revocation before the date
the Act becomes effective.

SECTION 106.   Notices, Etc., to Trustee and Company.

         Any request, demand, authorization, direction, notice, consent, waiver
or Act of Holders or other document provided or permitted by this Indenture to
be made upon, given or furnished to, or filed with,

                  (1) the Trustee by any Holder or by the Company shall be
         sufficient for every purpose hereunder if made, given, furnished or
         filed in writing to or with the Trustee at its Corporate Trust Office,
         Attention: Global Trust Service Department, or

                  (2) the Company by the Trustee or by any Holder shall be
         sufficient for every purpose hereunder (unless otherwise herein
         expressly provided) if in writing and mailed, first-class postage
         prepaid, to the Company addressed to it at the address of its principal
         office specified in the first paragraph of this Indenture or at any
         other address previously furnished in writing to the Trustee by the
         Company, Attention: Corporate Secretary.

SECTION 107.   Notice to Holders; Waiver.

         Where this Indenture provides for notice to Holders of Securities of
any event, such notice shall be sufficiently given (unless otherwise herein
expressly provided) if in writing and mailed, first-class postage prepaid, to
each Holder affected by such event, at the address of such Holder as it appears
in the Security Register, not later than the latest date, and not earlier than
the earliest date, prescribed for the giving of such notice.

         In case by reason of the suspension of regular mail service, or by
reason of any other cause it shall be impracticable to give such notice to
Holders of Securities by mail, then such notification as shall be made with the


                                      -9-

<PAGE>   16


approval of the Trustee shall constitute a sufficient notification for every
purpose hereunder. In any case in which notice to Holders of Securities is given
by mail, neither the failure to mail such notice, nor any defect in any notice
so mailed, to any particular Holder of a Security, shall affect the sufficiency
of such notice with respect to other Holders of Securities.

         Where this Indenture provides for notice in any manner, such notice may
be waived in writing by the Person entitled to receive such notice, either
before or after the event, and such waiver shall be the equivalent of such
notice. Waivers of notice by Holders shall be filed with the Trustee, but such
filing shall not be a condition precedent to the validity of any action taken in
reliance upon such waiver.

SECTION 108.   Conflict With Trust Indenture Act.

         If any provision hereof limits, qualifies or conflicts with any
provision of the Trust Indenture Act or another provision hereof required to be
included in this Indenture by any of the provisions of the Trust Indenture Act,
such provision of the Trust Indenture Act shall control. If any provision of
this Indenture modifies or excludes any provision of the Trust Indenture Act
that may be so modified or excluded, the former provision shall be deemed to
apply to this Indenture as so modified or to be excluded.

SECTION 109.   Effect of Headings and Table of Contents.

         The Article and Section headings herein and the Table of Contents are
for convenience only and shall not affect the construction hereof.

SECTION 110.   Successors and Assigns.

         All covenants and agreements in this Indenture by the Company shall
bind its successors and assigns, whether or not so expressed.

SECTION 111.   Separability Clause.

         In case any provision in this Indenture or in the Securities shall be
invalid, illegal or unenforceable, the validity, legality and enforceability of
the remaining provisions shall not in any way be affected or impaired thereby.

SECTION 112.   Benefits of Indenture.

         Nothing in this Indenture or in the Securities, express or implied,
shall give to any Person any benefit or any legal or equitable right, remedy or
claim under this Indenture, other than the parties hereto and their successors
hereunder, any Authenticating Agent, Paying Agent or Security Registrar and the
Holders and any holders of any Senior Indebtedness.

SECTION 113.   Governing Law.

         This Indenture and the Securities shall be governed by and construed in
accordance with the laws of the State of New York, but without giving effect to
applicable principles of conflicts of law to the extent the application of the
laws of another jurisdiction would be required thereby.

SECTION 114.   Legal Holidays.

         In any case where any Interest Payment Date, Redemption Date or Stated
Maturity of any Security shall not be a Business Day at any Place of Payment,
then (notwithstanding any other provision of this Indenture or of the
Securities) payment of principal of, premium (if any) and interest on or any
Additional Amounts with respect to Securities of any series need not be made at
such Place of Payment on such date, but may be made on the next succeeding
Business Day at such Place of Payment with the same force and effect as if made
on the Interest Payment Date or Redemption Date, or at the Stated Maturity,
provided that no interest shall accrue with respect to such payment for the
period from and after such Interest Payment Date, Redemption Date or Stated
Maturity, as the case may be.


                                      -10-
<PAGE>   17


SECTION 115.   Corporate Obligation.

         No recourse may be taken, directly or indirectly, against any
incorporator, subscriber to the capital stock, stockholder, officer, director or
employee of the Company or the Trustee or of any predecessor or successor of the
Company or the Trustee with respect to the Company's obligations on the
Securities or the obligations of the Company or the Trustee under this Indenture
or any certificate or other writing delivered in connection herewith.

                                   ARTICLE TWO

                                 SECURITY FORMS

SECTION 201.   Forms Generally.

         The Securities of each series shall be in fully registered form and in
substantially such form or forms (including temporary or permanent global form)
as shall be established by or pursuant to a Board Resolution or in one or more
indentures supplemental hereto, in each case with such appropriate insertions,
omissions, substitutions and other variations as are required or permitted by
this Indenture and may have such letters, numbers or other marks of
identification and such legends or endorsements placed thereon as may be
required to comply with the rules of any securities exchange or as may,
consistently herewith, be determined by the officers of the Company executing
such Securities, as evidenced by their execution of the Securities. If temporary
Securities of any series are issued in global form as permitted by Section 304,
the form thereof shall be established as provided in the preceding sentence. A
copy of the Board Resolution establishing the form or forms of Securities of any
series (or any such temporary global Security) shall be delivered to the Trustee
at or prior to the delivery of the Company Order contemplated by Section 303 for
the authentication and delivery of such Securities (or any such temporary global
Security).

         The definitive Securities shall be printed, lithographed or engraved on
steel engraved borders or may be produced in any other manner, all as determined
by the officers executing such Securities, as evidenced by their execution
thereof.

SECTION 202.   Form of Trustee's Certificate of Authentication.

         The Trustee's certificate of authentication shall be in substantially
the following form:

                  "This is one of the Securities of the series designated
         therein referred to in the within-mentioned Indenture.

                                   Chase Bank of Texas, National Association
                                   as Trustee

                                   By
                                      ---------------------------------------   
                                      Authorized Signatory"

SECTION 203.   Securities in Global Form.

         If Securities of a series are issuable in global form, as contemplated
by Section 301, then, notwithstanding clause (10) of Section 301 and the
provisions of Section 302, any such Security shall represent such of the
Outstanding Securities of such series as shall be specified therein and may
provide that it shall represent the aggregate amount of Outstanding Securities
from time to time endorsed thereon and that the aggregate amount of Outstanding
Securities represented thereby may from time to time be reduced to reflect
exchanges or redemptions. Any endorsement of a Security in global form to
reflect the amount, or any increase or decrease in the amount, of Outstanding
Securities represented thereby shall be made by the Trustee in such manner and
upon instructions given by such Person or Persons as shall be specified in such
Security or in a Company Order to be delivered to the Trustee pursuant to
Section 303 or Section 304. Subject to the provisions of Section 303 and, if
applicable, Section 304, the Trustee shall deliver and redeliver any Security in
permanent global form in the manner and upon instructions given by the Person or
Persons specified in such Security or in the applicable Company Order. With
respect to the Securities of any series that are 


                                      -11-


<PAGE>   18

represented by a Security in global form, the Company authorizes the execution
and delivery by the Trustee of a letter of representations or other similar
agreement or instrument in the form customarily provided for by the Depositary
appointed with respect to such global Security. Any Security in global form may
be deposited with the Depositary or its nominee, or may remain in the custody of
the Security Custodian therefor pursuant to an agreement between the Trustee and
the Depositary. If a Company Order pursuant to Section 303 or 304 has been, or
simultaneously is, delivered, any instructions by the Company with respect to
endorsement or delivery or redelivery of a Security in global form shall be in
writing but need not comply with Section 103 and need not be accompanied by an
Opinion of Counsel.

         Members of, or participants in, the Depositary ("Agent Members") shall
have no rights under this Indenture with respect to any Security issued in
global form held on their behalf by the Depositary, or the Security Custodian as
its custodian, or under such global Security, and the Depositary may be treated
by the Company, the Security Custodian and any agent of the Company or the
Trustee as the absolute owner of such global Security for all purposes
whatsoever. Notwithstanding the foregoing, (i) the registered holder of a
Security of any series issued in global form may grant proxies and otherwise
authorize any Person, including Agent Members and Persons that may hold
interests through Agent Members, to take any action that a Holder of such series
is entitled to take under this Indenture or the Securities of such series and
(ii) nothing herein shall prevent the Company, the Security Custodian or any
agent of the Company or the Security Custodian, from giving effect to any
written certification, proxy or other authorization furnished by the Depositary
or shall impair, as between the Depositary and its Agent Members, the operation
of customary practices governing the exercise of the rights of a beneficial
owner of any Security.

         Notwithstanding Section 305, except as otherwise specified as
contemplated by Section 301, any permanent global Security shall be exchangeable
only as provided in this paragraph. If the beneficial owners of interests in a
permanent global Security are entitled to exchange such interest for Securities
of such series and of like tenor and principal amount of another authorized form
and denomination, as specified as contemplated by Section 301, then without
unnecessary delay but in any event not later than the earliest date on which
such interests may be so exchanged, the Company shall deliver to the Trustee
definitive Securities of that series in an aggregate principal amount equal to
the principal amount of such permanent global Security, executed by the Company.
On or after the earliest date on which such interests may be so exchanged, such
permanent global Security shall be surrendered from time to time in accordance
with instructions given to the Trustee and the Depositary (which instructions
shall be in writing but need not comply with Section 103 or be accompanied by an
Opinion of Counsel) by the Depositary or such other depositary as shall be
specified in the Company Order with respect thereto to the Trustee, as the
Company's agent for such purpose, to be exchanged, in whole or in part, for
definitive Securities of the same series without charge and the Trustee shall
authenticate and deliver, in exchange for each portion of such permanent global
Security, a like aggregate principal amount of other definitive Securities of
the same series of authorized denominations and of like tenor as the portion of
such permanent global Security to be exchanged; provided, however, that no such
exchanges may occur during a period beginning at the opening of business 15 days
before any selection of Securities of that series is to be redeemed and ending
on the relevant Redemption Date. Promptly following any such exchange in part,
such permanent global Security marked to evidence the partial exchange shall be
returned by the Trustee to the Depositary or such other depositary referred to
above in accordance with the instructions of the Company referred to above. If a
definitive Security is issued in exchange for any portion of a permanent global
Security after the close of business at the office or agency where such exchange
occurs on (i) any Regular Record Date and before the opening of business at such
office or agency on the relevant Interest Payment Date, or (ii) any Special
Record Date and before the opening of business at such office or agency on the
related proposed date for payment of Defaulted Interest, interest or Defaulted
Interest, as the case may be, will not be payable on such Interest Payment Date
or proposed date for payment, as the case may be, in respect of such Security,
but will be payable on such Interest Payment Date or proposed for payment, as
the case may be, only to the Person to whom interest in respect of such portion
of such permanent global Security is payable in accordance with the provisions
of this Indenture.

         Notwithstanding Section 305, except as otherwise specified as
contemplated by Section 301, transfers of a Security issued in global form shall
be limited to transfers of such global Security in whole, but not in part, to
the Depositary, its successors or their respective nominees. Interests of
beneficial owners in a Security issued in global form may be transferred in
accordance with the rules and procedures of the Depositary. Securities of any
series shall be transferred to all beneficial owners of a global Security of
such series in exchange for their beneficial interests in that global Security
if, and only if, either (1) the Depositary notifies the Company that it is
unwilling or unable to continue as Depositary for the global Security of such
series and a successor Depositary is not appointed by the Company within


                                      -12-

<PAGE>   19


90 days of such notice, (2) an Event of Default has occurred with respect to
such series and is continuing and the Security Registrar has received a request
from the Depositary or the Trustee to issue Securities of such series in lieu of
all or a portion of that global Security (in which case the Company shall
deliver Securities of such series within 30 days of such request) or (3) the
Company determines not to have the Securities of such series represented by a
global Security.

         In connection with any transfer of a portion of the beneficial interest
in a global Security of any series to beneficial owners pursuant to this Section
203, the Security Registrar shall reflect on its books and records the date and
a decrease in the principal amount of the global Security of that series in an
amount equal to the principal amount of the beneficial interest in the global
Security of that series to be transferred, and the Company shall execute, and
the Trustee upon receipt of a Company Order for the authentication and delivery
of Securities of that series shall authenticate and deliver, one or more
Securities of the same series of like tenor and amount.

         In connection with the transfer of all the beneficial interests in a
global Security of any series to beneficial owners pursuant to this Section 203,
the global Security shall be deemed to be surrendered to the Trustee for
cancellation, and the Company shall execute, and the Trustee shall authenticate
and deliver, to each beneficial owner identified by the Depositary in exchange
for its beneficial interest in the global Security, an equal aggregate principal
amount of Securities of that series of authorized denominations.

         Neither the Company nor the Trustee will have any responsibility or
liability for any aspect of the records relating to, or payments made on account
of, Securities of any series by the Depositary, or for maintaining, supervising
or reviewing any records of the Depositary relating to such Securities. Neither
the Company nor the Trustee shall be liable for any delay by the related global
Security Holder or the Depositary in identifying the beneficial owners, and each
such Person may conclusively rely on, and shall be protected in relying on,
instructions from such global Security Holder or the Depositary for all purposes
(including with respect to the registration and delivery, and the respective
principal amounts, of the Securities to be issued).

         The provisions of the last sentence of Section 303 shall apply to any
Security in global form if such Security was never issued and sold by the
Company and the Company delivers to the Trustee the Security in global form
together with written instructions (which need not comply with Section 103 and
need not be accompanied by an Opinion of Counsel) with regard to the reduction
in the principal amount of Securities represented thereby, together with the
written statement contemplated by the last sentence of Section 303.

         Notwithstanding the provisions of Sections 201 and 307, unless
otherwise specified as contemplated by Section 301, payment of principal of,
premium (if any) and interest on or any Additional Amounts with respect to any
Security in permanent global form shall be made to the Person or Persons
specified therein.

         Notwithstanding the provisions of Section 308 and except as provided in
the preceding paragraph, the Company, the Trustee and any agent of the Company
or of the Trustee shall treat a Person as the Holder of such principal amount of
Outstanding Securities represented by a global Security as shall be specified in
a written statement, if any, of the Holder of such global Security which is
produced to the Security Registrar by such Holder.

         Global Securities may be issued in either temporary or permanent form.
Permanent global Securities will be issued in definitive form.

                                  ARTICLE THREE

                                 THE SECURITIES

SECTION 301.   Amount Unlimited; Issuable in Series.

         The aggregate principal amount of Securities that may be authenticated
and delivered under this Indenture is unlimited.


                                      -13-

<PAGE>   20

         The Securities may be issued in one or more series. There shall be
established in or pursuant to a Board Resolution, and set forth in an Officers'
Certificate, or established in one or more indentures supplemental hereto, prior
to the issuance of Securities of any series,

                  (1) the title of the Securities of such series (which shall
         distinguish the Securities of the series from all other Securities);

                  (2) any limit upon the aggregate principal amount of the
         Securities of such series which may be authenticated and delivered
         under this Indenture (except for Securities authenticated and delivered
         upon registration of transfer of, or in exchange for, or in lieu of,
         other Securities of such series pursuant to Section 203, 304, 305, 306,
         906 or 1107);

                  (3) whether Securities of such series are to be issuable
         initially in temporary global form and whether any Securities of such
         series are to be issuable in permanent global form and, if so, whether
         beneficial owners of interests in any such global Security may exchange
         such interests for Securities of such series and of like tenor of any
         authorized form and denomination and the circumstances under which any
         such exchanges may occur, if other than in the manner provided in
         Sections 203 or 305, and the Depositary for any global Security or
         Securities of such series;

                  (4) the manner in which any interest payable on a temporary
         global Security of such series on any Interest Payment Date will be
         paid if other than in the manner provided in Section 304;

                  (5) the date or dates on which the principal or premium (if
         any) of the Securities of such series is payable or the method of
         determination thereof;

                  (6) the rate or rates, or the method of determination thereof,
         at which the Securities of such series shall bear interest, if any,
         whether and under what circumstances Additional Amounts with respect to
         such Securities shall be payable, the date or dates from which such
         interest shall accrue, the Interest Payment Dates on which such
         interest shall be payable and, if other than as set forth in Section
         101, the Regular Record Date for the interest payable on any Securities
         on any Interest Payment Date;

                  (7) the place or places where, subject to the provisions of
         Section 1002, the principal of, premium (if any) and interest on or any
         Additional Amounts with respect to the Securities of such series shall
         be payable;

                  (8) the period or periods within which, the price or prices
         (whether denominated in cash, securities or otherwise) at which and the
         terms and conditions upon which Securities of such series may be
         redeemed, in whole or in part, at the option of the Company, if the
         Company is to have that option, and the manner in which the Company
         must exercise any such option, if different from those set forth
         herein;

                  (9) the obligation, if any, of the Company to redeem or
         purchase Securities of such series pursuant to any sinking fund or
         analogous provisions or at the option of a Holder thereof and the
         period or periods within which, the price or prices (whether
         denominated in cash, securities or otherwise) at which and the terms
         and conditions upon which, Securities of such series shall be redeemed
         or purchased in whole or in part pursuant to such obligation;

                  (10) the denomination in which any Securities of that series
         shall be issuable, if other than denominations of $1,000 and any
         integral multiple thereof;

                  (11) the currency or currencies (including composite
         currencies), if other than Dollars, or the form, including equity
         securities, other debt securities (including Securities), warrants or
         any other securities or property of the Company or any other Person, in
         which payment of the principal of, premium (if any) and interest on or
         any Additional Amounts with respect to the Securities of such series
         shall be payable;



                                      -14-
<PAGE>   21


                  (12) if the principal of, premium (if any) or interest on or
         any Additional Amounts with respect to the Securities of such series
         are to be payable, at the election of the Company or a Holder thereof,
         in a currency or currencies (including composite currencies) other than
         that in which the Securities are stated to be payable, the currency or
         currencies (including composite currencies) in which payment of the
         principal of, premium (if any) and interest on or any Additional
         Amounts with respect to Securities of such series as to which such
         election is made shall be payable, and the periods within which and the
         terms and conditions upon which such election is to be made;

                  (13) if the amount of payments of principal of, premium (if
         any) and interest on or any Additional Amounts with respect to the
         Securities of such series may be determined with reference to any
         commodities, currencies or indices, values, rates or prices or any
         other index or formula, the manner in which such amounts shall be
         determined;

                  (14) if other than the entire principal amount thereof, the
         portion of the principal amount of Securities of such series that shall
         be payable upon declaration of acceleration of the Maturity thereof
         pursuant to Section 502;

                  (15) any additional means of satisfaction and discharge of
         this Indenture with respect to Securities of such series pursuant to
         Section 401, any additional conditions to discharge pursuant to Section
         401 or 403 and the application, if any, of Section 403;

                  (16) any deletions or modifications of or additions to the
         definitions set forth in Section 101, Events of Default set forth in
         Section 501 or covenants of the Company set forth in Article Ten
         pertaining to the Securities of such series;

                  (17) if the Securities of such series are to be convertible
         into or exchangeable for equity securities, other debt securities
         (including Securities), warrants or any other securities or property of
         the Company or any other Person, at the option of the Company or the
         Holder or upon the occurrence of any condition or event, the terms and
         conditions for such conversion or exchange;

                  (18) whether any of such Securities will be subject to certain
         optional interest rate reset provisions;

                  (19) the additions or changes, if any, to the Indenture with
         respect to such Securities as shall be necessary to permit or
         facilitate the issuance of such Securities in bearer form, registered
         or not registrable as to principal, and with or without interest
         coupons; and

                  (20) any other terms of such series (which terms shall not be
         inconsistent with the provisions of this Indenture).

         All Securities of any one series shall be substantially identical
except as to denomination and except as may otherwise be provided in or pursuant
to the Board Resolution referred to above and (subject to Section 303) set
forth, or determined in the manner provided, in the Officers' Certificate
referred to above or in any such indenture supplemental hereto.

         At the option of the Company, interest on the Securities of any series
that bears interest may be paid by mailing a check to the address of any Holder
as such address shall appear in the Security Register.

         If any of the terms of the series are established by action taken
pursuant to a Board Resolution, a copy of an appropriate record of such action
together with such Board Resolution shall be certified by the Secretary or an
Assistant Secretary of the Company and delivered to the Trustee at or prior to
the delivery of the Officers' Certificate setting forth the terms of the series.

         The Securities shall be subordinated in right of payment to Senior
Indebtedness as provided in Article Thirteen.


                                      -15-



<PAGE>   22


SECTION 302.   Denominations.

         The Securities of each series shall be issuable in such denominations
as shall be specified as contemplated by Section 301. In the absence of any such
provisions with respect to the Securities of any series, the Securities of such
series denominated in Dollars shall be issuable in denominations of $1,000 and
any integral multiple thereof. Unless otherwise provided as contemplated by
Section 301 with respect to any series of Securities, any Securities of a series
denominated in a currency other than Dollars shall be issuable in denominations
that are the equivalent, as determined by the Company by reference to the noon
buying rate in The City of New York for cable transfers for such currency
("Exchange Rate"), as such rate is reported or otherwise made available by the
Federal Reserve Bank of New York, on the applicable issue date for such
Securities, of $1,000 and any integral multiple thereof.

SECTION 303.   Execution, Authentication, Delivery and Dating.

         The Securities shall be executed on behalf of the Company by its
Chairman of the Board, its President, its Treasurer or one of its Vice
Presidents, under its corporate seal reproduced thereon or affixed thereto
attested by its Secretary or one of its Assistant Secretaries. The signature of
any of these officers on the Securities may be manual or facsimile.

         Securities bearing the manual or facsimile signatures of individuals
who were at any time the proper officers of the Company shall bind the Company,
notwithstanding that such individuals or any of them have ceased to hold such
offices prior to the authentication and delivery of such Securities or did not
hold such offices at the date of such Securities.

         At any time and from time to time after the execution and delivery of
this Indenture, the Company may deliver Securities of any series executed by the
Company to the Trustee for authentication, together with a Company Order for the
authentication and delivery of such Securities, and the Trustee in accordance
with the Company Order shall authenticate and deliver such Securities as in this
Indenture provided and not otherwise.

         If the form or terms of the Securities of a series have been
established in or pursuant to one or more Board Resolutions or any other method
permitted by Sections 201 and 301, in authenticating such Securities, and
accepting the additional responsibilities under this Indenture in relation to
such Securities, the Trustee shall be entitled to receive, and (subject to
Section 601) shall be fully protected in relying upon, an Opinion of Counsel
stating that,

                  (a) if the form of such Securities has been established in
         conformity with the provisions of this Indenture;

                  (b) if the terms of such Securities have been established in
         conformity with the provisions of this Indenture; and

                  (c) that such Securities when authenticated and delivered by
         the Trustee and issued by the Company in the manner and subject to any
         conditions specified in such Opinion of Counsel, will constitute legal,
         valid and binding obligations of the Company, enforceable in accordance
         with their terms, except as such enforcement is subject to the effect
         of (i) bankruptcy, insolvency, fraudulent conveyance, reorganization or
         other laws relating to or affecting creditors' rights and (ii) general
         principles of equity (regardless of whether such enforcement is
         considered in a proceeding in equity or at law).

If such form or terms have been so established, the Trustee shall not be
required to authenticate such Securities if the issue of such Securities
pursuant to this Indenture will affect the Trustee's own rights, duties or
immunities under the Securities and this Indenture or otherwise in a manner not
reasonably acceptable to the Trustee.

         Each Security shall be dated the date of its authentication.

         No Security shall be entitled to any benefit under this Indenture or be
valid or obligatory for any purpose unless there appears on such Security a
certificate of authentication substantially in the form provided for herein
executed by the Trustee by manual signature, and such certificate upon any
Security shall be conclusive evidence, and the only 



                                      -16-
<PAGE>   23

evidence, that such Security has been duly authenticated and delivered
hereunder. Notwithstanding the foregoing, if any Security shall have been
authenticated and delivered hereunder but never issued and sold by the Company,
and the Company shall deliver such Security to the Trustee for cancellation as
provided in Section 309 together with a written statement (which need not comply
with Section 103 and need not be accompanied by an Opinion of Counsel) stating
that such Security has never been issued and sold by the Company, for all
purposes of this Indenture such Security shall be deemed never to have been
authenticated and delivered hereunder and shall never be entitled to the
benefits of this Indenture.

SECTION 304.   Temporary Securities.

         Pending the preparation of definitive Securities of any series, the
Company may execute, and upon Company Order the Trustee shall authenticate and
deliver, temporary Securities that are printed, lithographed, typewritten,
mimeographed or otherwise produced, in any authorized denomination,
substantially of the tenor of the definitive Securities in lieu of which they
are issued, in registered form and with such appropriate insertions, omissions,
substitutions and other variations as the officers of the Company executing such
Securities may determine, as evidenced by their execution of such Securities.

         Except in the case of temporary Securities in global form (which shall
be exchanged in accordance with the provisions of the following paragraphs), if
temporary Securities of any series are issued, the Company will cause definitive
Securities of that series to be prepared without unreasonable delay. After the
preparation of definitive Securities of such series, the temporary Securities of
such series shall be exchangeable for definitive Securities of such series upon
surrender of the temporary Securities of such series at the office or agency of
the Company in a Place of Payment for that series, without charge to the Holder.
Upon surrender for cancellation of any one or more temporary Securities of any
series, the Company shall execute and deliver a Company Order requesting the
Trustee to authenticate and deliver and the Trustee shall authenticate and
deliver in exchange therefor a like principal amount of definitive Securities of
the same series of authorized denominations. Until so exchanged the temporary
Securities of any series shall in all respects be entitled to the same benefits
under this Indenture as definitive Securities of such series.

         All Outstanding temporary Securities of any series shall in all
respects be entitled to the same benefits under this Indenture as definitive
Securities of the same series and of like tenor authenticated and delivered
hereunder.

SECTION 305.   Registration, Registration of Transfer and Exchange.

         The Company shall cause to be kept for each series of Securities at one
of the offices or agencies maintained pursuant to Section 1002 a register (the
register maintained in such office and in any other office or agency of the
Company in a Place of Payment being herein sometimes collectively referred to as
the "Security Register") in which, subject to such reasonable regulations as it
may prescribe, the Company shall provide for the registration of Securities and
of transfers of Securities of such series. The Trustee is hereby initially
appointed "Security Registrar" for the purpose of registering Securities and
transfers of Securities as herein provided.

         Except as set forth in Section 203 or as may be provided pursuant to
Section 301, upon surrender for registration of transfer of any Security of any
series at the office or agency in a Place of Payment for that series, the
Company shall execute and deliver a Company Order requesting the Trustee to
authenticate and deliver and the Trustee shall authenticate and deliver, in the
name of the designated transferee or transferees, one or more new Securities of
the same series and of like tenor, of any authorized denominations and of a like
aggregate principal amount.

         At the option of the Holder, Securities of any series may be exchanged
for other Securities of the same series and of like tenor, of any authorized
denominations and of a like aggregate principal amount, upon surrender of the
Securities to be exchanged at such office or agency. Whenever any Securities are
so surrendered for exchange, the Company shall execute, and the Trustee shall
authenticate and deliver, the Securities which the Holder making the exchange is
entitled to receive.

         All Securities issued upon any registration of transfer or exchange of
Securities shall be the valid obligations of the Company, evidencing the same
debt, and entitled to the same benefits under this Indenture, as the Securities
surrendered upon such registration of transfer or exchange.


                                      -17-

<PAGE>   24


         Every Security presented or surrendered for registration of transfer or
for exchange shall (if so required by the Company or the Trustee) be duly
endorsed, or be accompanied by a written instrument of transfer in form
satisfactory to the Company and the Security Registrar duly executed, by the
Holder thereof or his attorney duly authorized in writing.

         No service charge shall be made for any registration of transfer or
exchange of Securities, but the Company may require payment of a sum sufficient
to cover any tax or other governmental charge that may be imposed in connection
with any registration of transfer or exchange of Securities, other than exchange
pursuant to Section 304, 906 or 1107 not involving any transfer.

         The Company shall not be required (i) to issue, register the transfer
of or exchange Securities of any series during a period beginning at the opening
of business 15 days before the day of the mailing of a notice of redemption of
Securities of such series selected for redemption and ending at the close of
business on the day of the mailing of the relevant notice of redemption or (ii)
to register the transfer of or exchange any Security so selected for redemption
in whole or in part, except the unredeemed portion of any Security being
redeemed in part.

SECTION 306.   Mutilated, Destroyed, Lost and Stolen Securities.

         If any mutilated Security is surrendered to the Trustee, the Company
shall execute and deliver a Company Order requesting the Trustee to authenticate
and deliver and the Trustee shall authenticate and deliver in exchange therefor
a new Security of the same series and of like tenor and principal amount and
bearing a number not contemporaneously outstanding.

         If there shall be delivered to the Company and the Trustee (i) evidence
to their satisfaction of the destruction, loss or theft of any Security and (ii)
such security or indemnity as may be required by them to save each of them and
any agent of either of them harmless, then, in the absence of notice to the
Company or the Trustee that such Security has been acquired by a bona fide
purchaser, the Company shall execute and upon the Company's request the Trustee
shall authenticate and deliver, in lieu of any such destroyed, lost or stolen
Security, a new Security of the same series and of like tenor and principal
amount and bearing a number not contemporaneously outstanding.

         In case any such mutilated, destroyed, lost or stolen Security has
become or is about to become due and payable, the Company in its discretion may,
instead of issuing a new Security, pay such Security.

         Upon the issuance of any new Security under this Section 306, the
Company may require the payment of a sum sufficient to cover any tax or other
governmental charge that may be imposed in relation thereto and any other
expenses (including the fee and expenses of the Trustee) connected therewith.

         Every new Security of any series issued pursuant to this Section 306 in
lieu of any destroyed, lost or stolen Security shall constitute an original
additional contractual obligation of the Company, whether or not the destroyed,
lost or stolen Security shall be at any time enforceable by anyone, and shall be
entitled to all the benefits of this Indenture equally and proportionately with
any and all other Securities of that series duly issued hereunder.

         The provisions of this Section 306 are exclusive and shall preclude (to
the extent lawful) all other rights and remedies with respect to the replacement
or payment of mutilated, destroyed, lost or stolen Securities.

SECTION 307.   Payment of Interest; Interest Rights Preserved.

         Interest on any Security which is payable, and is punctually paid or
duly provided for, on any Interest Payment Date shall be paid to the Person in
whose name that Security (or one or more Predecessor Securities) is registered
at the close of business on the Regular Record Date for such interest. Unless
otherwise provided with respect to the Securities of any series, payment of
interest may be made at the option of the Company by check mailed or delivered
to the address of any Person entitled thereto as such address shall appear in
the Security Register.

         Any interest on any Security of any series which is payable, but is not
punctually paid or duly provided for, on any Interest Payment Date (herein
called "Defaulted Interest") shall forthwith cease to be payable to the Holder
on



                                      -18-

<PAGE>   25

the relevant Regular Record Date by virtue of having been such Holder, and such
Defaulted Interest may be paid by the Company, at its election in each case, as
provided in clause (1) or (2) below:

                  (1) The Company may elect to make payment of any Defaulted
         Interest to the Persons in whose names the Securities of such series
         (or their respective Predecessor Securities) are registered at the
         close of business on a Special Record Date for the payment of such
         Defaulted Interest, which shall be fixed in the following manner. The
         Company shall notify the Trustee in writing of the amount of Defaulted
         Interest proposed to be paid on each Security of such series and the
         date of the proposed payment, and at the same time the Company shall
         deposit with the Trustee an amount of money equal to the aggregate
         amount proposed to be paid in respect of such Defaulted Interest or
         shall make arrangements satisfactory to the Trustee for such deposit
         prior to the date of the proposed payment, such money when deposited to
         be held in trust for the benefit of the Persons entitled to such
         Defaulted Interest as in this clause (1) provided. Thereupon the
         Trustee shall fix a Special Record Date for the payment of such
         Defaulted Interest which shall be not more than 15 days and not less
         than 10 days prior to the date of the proposed payment and not less
         than 10 days after the receipt by the Trustee of the notice of the
         proposed payment. The Trustee shall promptly notify the Company of such
         Special Record Date and, in the name and at the expense of the Company,
         shall cause notice of the proposed payment of such Defaulted Interest
         and the Special Record Date therefor to be mailed, first-class postage
         prepaid, to each Holder of Securities of such series at his address as
         it appears in the Security Register, not less than 10 days prior to
         such Special Record Date. The Trustee may, in its discretion, in the
         name and at the expense of the Company, cause a similar notice to be
         published at least once in an Authorized Newspaper, but such
         publication shall not be a condition precedent to the establishment of
         such Special Record Date. Notice of the proposed payment of such
         Defaulted Interest and the Special Record Date therefor having been so
         mailed, such Defaulted Interest shall be paid to the Persons in whose
         names the Securities of such series (or their respective Predecessor
         Securities) are registered at the close of business on such Special
         Record Date and shall no longer be payable pursuant to the following
         clause (2).

                  (2) The Company may make payment of any Defaulted Interest on
         the Securities of any series in any other lawful manner not
         inconsistent with the requirements of any securities exchange on which
         such Securities may be listed, and upon such notice as may be required
         by such exchange, if, after notice given by the Company to the Trustee
         of the proposed payment pursuant to this clause (2), such manner of
         payment shall be deemed practicable by the Trustee.

         Subject to the foregoing provisions of this Section 307, each Security
delivered under this Indenture, upon registration of transfer of, in exchange
for or in lieu of, any other Security, shall carry the rights to interest
accrued and unpaid, and to accrue, which were carried by such other Security.

SECTION 308.   Persons Deemed Owners.

         Prior to due presentment of a Security for registration of transfer,
the Company, the Trustee and any agent of the Company or the Trustee may treat
the Person in whose name such Security is registered as the owner of such
Security for the purpose of receiving payment of principal of, premium (if any)
and (subject to Sections 305 and 307) interest on such Security and for all
other purposes whatsoever, whether or not such Security be overdue, and neither
the Company, the Trustee nor any agent of the Company or the Trustee shall be
affected by notice to the contrary.

SECTION 309.   Cancellation.

         All Securities surrendered for payment, redemption, registration of
transfer or exchange or for credit against any sinking fund payment shall, if
surrendered to any Person other than the Trustee, be delivered to the Trustee.
All Securities so delivered shall be promptly canceled by the Trustee. The
Company may at any time deliver to the Trustee for cancellation any Securities
previously authenticated and delivered hereunder which the Company may have
acquired in any manner whatsoever, and all Securities so delivered shall be
promptly canceled by the Trustee. No Securities shall be authenticated in lieu
of or in exchange for any Securities canceled as provided in this Section 309,
except as expressly permitted by this Indenture. All canceled Securities held by
the Trustee shall be disposed of by the Trustee in accordance with its customary
procedures, unless the Trustee is otherwise directed by a Company Order.



                                      -19-
<PAGE>   26


SECTION 310.   Computation of Interest.

         Except as otherwise specified as contemplated by Section 301 for
Securities of any series, interest on the Securities of each series shall be
computed on the basis of a year compressing twelve 30-day months.

SECTION 311.   CUSIP Numbers.

         The Company in issuing the Securities may use "CUSIP" numbers (if then
generally in use), and, if so, the Trustee shall use "CUSIP" numbers in notices
of redemption as a convenience to Holders; provided that any such notice may
state that no representation is made as to the correctness of such numbers
either as printed on the Securities or as contained in any notice of a
redemption and that reliance may be placed only on the other identification
numbers printed on the Securities, and any such redemption shall not be affected
by any defect in or omission of such numbers.

                                  ARTICLE FOUR

                           SATISFACTION AND DISCHARGE

SECTION 401.   Satisfaction and Discharge of Indenture.

         This Indenture shall upon Company Request cease to be of further effect
with respect to Securities of a series, and the Trustee, at the expense of the
Company, shall execute proper instruments acknowledging satisfaction and
discharge of this Indenture with respect to Securities of such series, when

                  (1)  either

                           (A) all Securities of such series theretofore
                  authenticated and delivered (other than (i) Securities that
                  have been destroyed, lost or stolen and that have been
                  replaced or paid as provided in Section 306, and (ii)
                  Securities for whose payment money has theretofore been
                  deposited in trust or segregated and held in trust by the
                  Company and thereafter repaid to the Company or discharged
                  from such trust, as provided in Section 1003) have been
                  delivered to the Trustee for cancellation;

                           (B) with respect to all Outstanding Securities of
                  such series not theretofore delivered to the Trustee for
                  cancellation, the Company has deposited or caused to be
                  deposited with the Trustee as trust funds, under the terms of
                  an irrevocable trust agreement in form and substance
                  satisfactory to the Trustee, for the purpose money or U.S.
                  Government Obligations maturing as to principal and interest
                  in such amounts and at such times as will, together with the
                  income to accrue thereon, without consideration of any
                  reinvestment thereof, be sufficient to pay and discharge the
                  entire indebtedness on all Outstanding Securities of such
                  series not theretofore delivered to the Trustee for
                  cancellation for principal of, premium (if any) and interest
                  on or any Additional Amounts with respect to such Securities
                  to the Stated Maturity or any Redemption Date contemplated by
                  the penultimate paragraph of this Section 401, as the case may
                  be; or

                           (C) the Company has properly fulfilled such other
                  means of satisfaction and discharge as is specified, as
                  contemplated by Section 301, to be applicable to the
                  Securities of such series;

                  (2) the Company has paid or caused to be paid all other sums
         payable hereunder by the Company with respect to the Outstanding
         Securities of such series;

                  (3) the Company has complied with any other conditions
         specified pursuant to Section 301 to be applicable to the discharge of
         Securities of such series pursuant to this Section 401;

                  (4) the Company has delivered to the Trustee an Officers'
         Certificate and an Opinion of Counsel, each stating that all conditions
         precedent herein provided for relating to the satisfaction and
         discharge of this Indenture with respect to the Outstanding Securities
         of such series have been complied with;


                                      -20-

<PAGE>   27


                  (5) if the conditions set forth in Section 401(1)(A) have not
         been satisfied, and unless otherwise specified pursuant to Section 301
         for the Securities of such series, the Company has delivered to the
         Trustee an Opinion of Counsel to the effect that the Holders of
         Securities of such series will not recognize income, gain or loss for
         United States federal income tax purposes as a result of such deposit,
         satisfaction and discharge and will be subject to United States federal
         income tax on the same amount and in the same manner and at the same
         time as would have been the case if such deposit, satisfaction and
         discharge had not occurred; and

                  (6) no Default or Event of Default with respect to the
         Securities of such issue shall have occurred and be continuing on the
         date of such deposit or, in so far as clause (5) or (6) of Section 501
         is concerned, at any time in the period ending on the 91st day after
         the date of such deposit (it being understood that this condition shall
         not be deemed satisfied until the expiration of such period).

         For the purposes of this Indenture, "U.S. Government Obligations" means
direct noncallable obligations of, or noncallable obligations the payment of
principal of and interest on which is guaranteed by, the United States of
America, or to the payment of which obligations or guarantees the full faith and
credit of the United States of America is pledged, or beneficial interests in a
trust the corpus of which consists exclusively of money or such obligations or a
combination thereof.

         If any Outstanding Securities of such series are to be redeemed prior
to their Stated Maturity, whether pursuant to any optional redemption provisions
or in accordance with any mandatory sinking fund requirement, the trust
agreement referred to in subclause (B) of clause (1) of this Section 401 shall
provide therefor and the Company shall make such arrangements as are
satisfactory to the Trustee for the giving of notice of redemption by the
Trustee in the name, and at the expense, of the Company.

         Notwithstanding the satisfaction and discharge of this Indenture with
respect to the Outstanding Securities of such series pursuant to this Section
401, the obligations of the Company to the Trustee under Section 607, the
obligations of the Company to any Authenticating Agent under Section 614 and,
except for a discharge pursuant to subclause (A) of clause (1) of this Section
401, the obligations of the Company under Sections 305, 306, 404, 1001 and 1002
and the obligations of the Trustee under Section 402 and the last paragraph of
Section 1003 shall survive.

SECTION 402.   Application of Trust Money.

         Subject to the provisions of the last paragraph of Section 1003, all
money deposited with the Trustee pursuant to Section 401 shall be held in trust
and applied by it, in accordance with the provisions of the Securities and this
Indenture, to the payment, either directly or through any Paying Agent
(including the Company acting as its own Paying Agent) as the Trustee may
determine, to the Persons entitled thereto, of the principal of, premium (if
any) and interest on or any Additional Amounts with respect to Securities of
such Securities for the payment of which such money has been deposited with the
Trustee.

SECTION 403.   Discharge of Liability on Securities of Any Series.

         If this Section 403 is specified, as contemplated by Section 301, to be
applicable to Securities of any series, the Company shall be deemed to have paid
and discharged the entire indebtedness on all the Outstanding Securities of such
series, the obligation of the Company under this Indenture and the Securities of
such series to pay the principal of, premium (if any) and interest on and any
Additional Amounts with respect to Securities of such series shall cease,
terminate and be completely discharged, and the Trustee, at the expense of the
Company, shall execute proper instruments acknowledging such satisfaction and
discharge, when

                  (1) the Company has complied with the provisions of Section
         401 of this Indenture (other than any additional conditions specified
         pursuant to Sections 301 and 401(3) and except that the Opinion of
         Counsel referred to in Section 401(5) shall state that it is based on a
         ruling by the Internal Revenue Service or other change since the date
         hereof under applicable Federal income tax law) with respect to all
         Outstanding Securities of such series,


                                      -21-

<PAGE>   28


                  (2) the Company has delivered to the Trustee a Company Request
         requesting such satisfaction and discharge,

                  (3) the Company has complied with any other conditions
         specified pursuant to Section 301 to be applicable to the discharge of
         Securities of such series pursuant to this Section 403, and

                  (4) the Company has delivered to the Trustee an Officers'
         Certificate and an Opinion of Counsel, each stating that all conditions
         precedent herein provided for relating to the discharge of the
         indebtedness on the Outstanding Securities of such series have been
         complied with.

         Upon the satisfaction of the conditions set forth in this Section 403
with respect to all the Outstanding Securities of any series, the terms and
conditions of such series, including the terms and conditions with respect
thereto set forth in this Indenture, shall no longer be binding upon, or
applicable to, the Company; provided that, the Company shall not be discharged
from any payment obligations in respect of Securities of such series which are
deemed not to be Outstanding under clause (iii) of the definition thereof if
such obligations continue to be valid obligations of the Company under
applicable law or pursuant to Section 305 or 306.

SECTION 404.   Reinstatement.

         If the Trustee or Paying Agent is unable to apply any money or U.S.
Government Obligations deposited with respect to Securities of any series in
accordance with Section 401 by reason of any legal proceeding or by reason of
any order or judgment of any court or governmental authority enjoining,
restraining or otherwise prohibiting such application, the Company's obligations
under this Indenture with respect to the Securities of such series and the
Securities of such series shall be revived and reinstated as though no deposit
had occurred pursuant to Section 401 until such time as the Trustee or Paying
Agent is permitted to apply all such money or U.S. Government Obligations in
accordance with Section 401; provided, however, that if the Company has made any
payment of principal of, premium (if any) or interest on or any Additional
Amounts with respect to any Securities because of the reinstatement of its
obligations, the Company shall be subrogated to the rights of the Holders of
such Securities to receive such payment from the money or U.S.
Government Obligations held by the Trustee or Paying Agent.

                                  ARTICLE FIVE

                                    REMEDIES

SECTION 501.   Events of Default.

         "Event of Default," wherever used herein with respect to Securities of
any series, means any one of the following events (whatever the reason for such
Event of Default and whether it shall be occasioned by the provisions of Article
Thirteen or be voluntary or involuntary or effected by operation of law or
pursuant to any judgment, decree or order of any court or any order, rule or
regulation of any administrative or governmental body), unless it is either
inapplicable to a particular series or it is specifically deleted or modified in
or pursuant to the supplemental indenture or Board Resolution establishing such
series of Securities or in the form of Security for such series:

                  (1) default in the payment of any interest on or any
         Additional Amounts with respect to any Security of that series when
         such interest or Additional Amounts become due and payable, and
         continuance of such default for a period of 60 days; or

                  (2) default in the payment of the principal of or premium (if
         any) on any Security of that series at its Maturity; or

                  (3) default in the deposit of any mandatory sinking fund
         payment, when and as due by the terms of a Security of that series, and
         continuance of such default for a period of 60 days; or

                  (4) default in the performance or breach of any covenant of
         the Company in this Indenture (other than a covenant a default in whose
         performance or whose breach is elsewhere in this Section 501
         specifically 



                                      -22-
<PAGE>   29


         dealt with or which has expressly been included in this Indenture
         solely for the benefit of one or more series of Securities other than
         that series), and continuance of such default or breach for a period of
         90 days after there has been given, by registered or certified mail, to
         the Company by the Trustee or to the Company and the Trustee by the
         Holders of at least 25% in principal amount of all Outstanding
         Securities a written notice specifying such default or breach and
         requiring it to be remedied and stating that such notice is a "Notice
         of Default" hereunder; or

                  (5) the entry by a court having jurisdiction in the premises
         of (A) a decree or order for relief in respect of the Company in an
         involuntary case or proceeding under any applicable federal or state
         bankruptcy, insolvency, reorganization or other similar law or (B) a
         decree or order adjudging the Company a bankrupt or insolvent, or
         approving as properly filed a petition seeking reorganization,
         arrangement, adjustment or composition of or in respect of the Company
         under any applicable federal or state law, or appointing a custodian,
         receiver, liquidator, assignee, trustee, sequestrator or other similar
         official of the Company or of any substantial part of its property, or
         ordering the winding up or liquidation of its affairs, and the
         continuance of any such decree or order for relief or any such other
         decree or order unstayed and in effect for a period of 90 consecutive
         days; or

                  (6) the commencement by the Company of a voluntary case or
         proceeding under any applicable federal or state bankruptcy,
         insolvency, reorganization or other similar law or of any other case or
         proceeding to be adjudicated a bankrupt or insolvent, or the consent by
         it to the entry of a decree or order for relief in respect of the
         Company in an involuntary case or proceeding under any applicable
         federal or state bankruptcy, insolvency, reorganization or other
         similar law or to the commencement of any bankruptcy or insolvency case
         or proceeding against it, or the filing by it, of a petition or answer
         or consent seeking reorganization or relief under any applicable
         federal or state law, or the consent by it to the filing of such
         petition or to the appointment of or taking possession by a custodian,
         receiver, liquidator, assignee, trustee, sequestrator or similar
         official of the Company or of any substantial part of its property, or
         the making by it of an assignment for the benefit of creditors, or the
         admission by it in writing of its inability to pay its debts generally
         as they become due, or the taking of corporate action by the Company in
         furtherance of any such action; or

                  (7) any other Event of Default provided with respect to
         Securities of that series.

         Notwithstanding the foregoing provisions of this Section 501, if the
principal of, premium (if any) or any interest on or any Additional Amounts with
respect to any Security is payable in a currency or currencies (including a
composite currency) other than Dollars and such currency or currencies are not
available to the Company for making payment thereof due to the imposition of
exchange controls or other circumstances beyond the control of the Company (a
"Conversion Event"), the Company will be entitled to satisfy its obligations to
Holders of the Securities by making such payment in Dollars in an amount equal
to the Dollar equivalent of the amount payable in such other currency, as
determined by the Company by reference to the Exchange Rate, as such Exchange
Rate is certified for customs purposes by the Federal Reserve Bank of New York
on the date of such payment, or, if such rate is not then available, on the
basis of the most recently available Exchange Rate. Notwithstanding the
foregoing provisions of this Section 501, any payment made under such
circumstances in Dollars where the required payment is in a currency other than
Dollars will not constitute an Event of Default under this Indenture.

         Promptly after the occurrence of a Conversion Event with respect to the
Securities of any series, the Company shall give written notice thereof to the
Trustee; and the Trustee, promptly after receipt of such notice, shall give
notice thereof in the manner provided in Section 107 to the Holders of such
series. Promptly after the making of any payment in Dollars as a result of a
Conversion Event with respect to the Securities of any series, the Company shall
give notice in the manner provided in Section 107 to the Holders of such series,
setting forth the applicable Exchange Rate and describing the calculation of
such payments.

SECTION 502.   Acceleration of Maturity; Rescission and Annulment.

         If an Event of Default with respect to any Securities of any series at
the time Outstanding occurs and is continuing, then in every such case the
Trustee or the Holders of not less than 25% in principal amount of the
Outstanding Securities of (i) the series affected by such default (in the case
of an Event of Default described in clause


                                      -23-

<PAGE>   30

(1), (2), (3) or (7) of Section 501) or (ii) all series of Securities (in the
case of an Event of Default described in clause (4) of Section 501) may declare
the principal amount (or, if any such Securities are Original Issue Discount
Securities, such portion of the principal amount as may be specified in the
terms of that series) of all of the Securities of the series affected by such
default or all series, as the case may be, to be due and payable immediately, by
a notice in writing to the Company (and to the Trustee if given by Holders), and
upon any such declaration such amount shall become immediately due and payable.
If an Event of Default described in clause (5) or (6) of Section 501 shall
occur, the principal amount of the Outstanding Securities of all series ipso
facto shall become and be immediately due and payable without any declaration or
other act on the part of the Trustee or any Holder.

         At any time after such a declaration of acceleration with respect to
Securities of any series (or of all series, as the case may be) has been made
and before a judgment or decree for payment of the money due has been obtained
by the Trustee as hereinafter provided in this Article Five, the Holders of a
majority in principal amount of the Outstanding Securities of that series (or of
all series, as the case may be), by written notice to the Company and the
Trustee, may rescind and annul such declaration and its consequences if

                  (1) the Company has paid or deposited with the Trustee a sum
         sufficient to pay

                           (A) all overdue interest on, and any Additional
                  Amounts with respect to, all Securities of that series (or of
                  all series, as the case may be),

                           (B) the principal of or premium (if any) on any
                  Securities of that series (or of all series, as the case may
                  be) which have become due otherwise than by such declaration
                  of acceleration and interest thereon at the rate or rates
                  prescribed therefor in such Securities (in the case of
                  Original Issue Discount Securities, the Securities' Yield to
                  Maturity),

                           (C) to the extent that payment of such interest is
                  lawful, interest upon overdue interest and any Additional
                  Amounts at the rate or rates prescribed therefor in such
                  Securities (in the case of Original Issue Discount Securities,
                  the Securities' Yield to Maturity), and

                           (D) all sums paid or advanced by the Trustee
                  hereunder and the reasonable compensation, expenses,
                  disbursements and advances of the Trustee, its agents and
                  counsel and all other amounts due the Trustee under Section
                  607;

         and

                  (2) all Events of Default with respect to Securities of that
         series (or of all series, as the case may be), other than the
         nonpayment of the principal of Securities of that series (or of all
         series, as the case may be) which have become due solely by such
         declaration of acceleration, have been cured or waived as provided in
         Section 513.

No such rescission shall affect any subsequent default or impair any right
consequent thereon.

SECTION 503.   Collection of Indebtedness and Suits for Enforcement by Trustee.

         The Company covenants that if

                  (1) default is made in the payment of any installment of
         interest on, or any Additional Amounts with respect to, any Security of
         any series when such interest or Additional Amounts shall have become
         due and payable and such default continues for a period of 60 days, or

                  (2) default is made in the payment of the principal of or
         premium (if any) on any Security at the Maturity thereof,

the Company will, upon demand of the Trustee, pay to it, for the benefit of the
Holders of such Securities, the whole amount then due and payable on such
Securities for principal of, premium (if any) and interest on or any Additional


                                      -24-
<PAGE>   31


Amounts with respect to such Securities and, to the extent that payment of such
interest shall be legally enforceable, interest on any overdue principal,
premium (if any) and on any overdue interest or Additional Amounts, at the rate
or rates prescribed therefor in such Securities (or in the case of Original
Issue Discount Securities, the Securities' Yield to Maturity), and, in addition
thereto, such further amount as shall be sufficient to cover the costs and
expenses of collection, including the reasonable compensation, expenses,
disbursements and advances of the Trustee, its agents and counsel, and all other
amounts due the Trustee under Section 607.

         If the Company fails to pay such amounts forthwith upon such demand,
the Trustee, in its own name and as trustee of an express trust, may institute a
judicial proceeding for the collection of the sums so due and unpaid, may
prosecute such proceeding to judgment or final decree and may enforce the same
against the Company or any other obligor upon such Securities and collect the
moneys adjudged or decreed to be payable in the manner provided by law out of
the property of the Company or any other obligor upon such Securities, wherever
situated.

         If an Event of Default with respect to Securities of any series occurs
and is continuing, the Trustee may in its discretion proceed to protect and
enforce its rights and the rights of the Holders of Securities of such series by
such appropriate judicial proceedings as the Trustee shall deem most effectual
to protect and enforce any such rights, whether for the specific enforcement of
any covenant or agreement in this Indenture or in aid of the exercise of any
power granted herein, or to enforce any other proper remedy.

SECTION 504.   Trustee May File Proofs of Claim.

         In case of the pendency of any receivership, insolvency, liquidation,
bankruptcy, reorganization, arrangement, adjustment, composition or other
judicial proceeding relative to the Company or any other obligor upon the
Securities or the property of the Company or of such other obligor or their
creditors, the Trustee (irrespective of whether the principal (or lesser amount
in the case of Original Issue Discount Securities) of the Securities shall then
be due and payable as therein expressed or by declaration or otherwise and
irrespective of whether the Trustee shall have made any demand on the Company
for the payment of overdue principal of, premium (if any), interest on or any
Additional Amounts with respect to such Securities) shall be entitled and
empowered, by intervention in such proceeding or otherwise,

                  (i) to file and prove a claim for the whole amount of
         principal (or lesser amount in the case of Original Issue Discount
         Securities) (and premium, if any) and interest and any Additional
         Amounts owing and unpaid in respect of the Securities and to file such
         other papers or documents as may be necessary or advisable to have the
         claims of the Trustee (including any claim for the reasonable
         compensation, expenses, disbursements and advances of the Trustee, its
         agents and counsel) and of the Holders allowed in such judicial
         proceeding, and

                  (ii) to collect and receive any monies or other property
         payable or deliverable on any such claims and to distribute the same;
         and any custodian, receiver, assignee, trustee, liquidator,
         sequestrator or other similar official in any such judicial proceeding
         is hereby authorized by each Holder to make such payments to the
         Trustee and, in the event that the Trustee shall consent to the making
         of such payments directly to the Holders, to pay to the Trustee any
         amount due it for the reasonable compensation, expenses, disbursements
         and advances of the Trustee, its agents and counsel, and any other
         amounts due the Trustee under Section 607.

         Nothing herein contained shall be deemed to authorize the Trustee to
authorize or consent to or accept or adopt on behalf of any Holder any plan of
reorganization, arrangement, adjustment or composition affecting the Securities
or the rights of any Holder thereof or to authorize the Trustee to vote in
respect of the claim of any Holder in any such proceedings; provided, however,
that the Trustee may, on behalf of the Holders, vote for the election of a
trustee in bankruptcy or similar official.

SECTION 505.   Trustee May Enforce Claims Without Possession of Securities 
               or Coupons.

         All rights of action and claim under this Indenture or the Securities
may be prosecuted and enforced by the Trustee without possession of any of the
Securities or the production thereof in any proceeding relating thereto; any
such proceeding instituted by the Trustee shall be brought in its own name as
trustee of an express trust; after provision for 


                                      -25-

<PAGE>   32


the payment of the reasonable compensation, expenses, disbursements and advances
of the Trustee, its agents and counsel, and any other amounts due the Trustee
under Section 607, any recovery of judgment shall be for the ratable benefit of
the Holders of the Securities in respect of which such judgment has been
recovered.

SECTION 506.   Application of Money Collected.

         Subject to Article Thirteen, any money collected by the Trustee
pursuant to this Article Five shall be applied in the following order, at the
date or dates fixed by the Trustee and, in case of the distribution of such
money on account of principal of, premium (if any) or interest on or any
Additional Amounts with respect to any Securities, upon presentation of the
Securities, and the notation thereon of the payment if only partially paid and
upon surrender thereof if fully paid:

                  FIRST: To the payment of all amounts due the Trustee under
         Section 607;

                  SECOND: To the payment of the amounts then due and unpaid for
         principal of, premium (if any) and interest on and any Additional
         Amounts with respect to such Securities in respect of which or for the
         benefit of which such money has been collected, ratably, without
         preference or priority of any kind, according to the amounts due and
         payable on such Securities for principal of, premium (if any), interest
         on and Additional Amounts, respectively; and

                  THIRD: The balance, if any, to the Company.

         To the fullest extent allowed under applicable law, if for the purpose
of obtaining judgment against the Company in any court it is necessary to
convert the sum due in respect of the principal of, premium (if any) or interest
on or any Additional Amounts with respect to the Securities of any series (the
"Required Currency") into a currency in which a judgment will be rendered (the
"Judgment Currency"), the rate of exchange used shall be the rate at which in
accordance with normal banking procedures the Trustee could purchase in The City
of New York the Required Currency with the Judgment Currency on the New York
Business Day next preceding that on which final judgment is given. Neither the
Company nor the Trustee shall be liable for any shortfall nor shall it benefit
from any windfall in payments to Holders of Securities under this Section 506
caused by a change in exchange rates between the time the amount of a judgment
against it is calculated as above and the time the Trustee converts the Judgment
Currency into the Required Currency to make payments under this Section 506 to
Holders of Securities, but payment of such judgment shall discharge all amounts
owed by the Company on the claim or claims underlying such judgment.

SECTION 507.   Limitation on Suits.

         Subject to Section 508, no Holder of any Security of any series shall
have any right to institute any proceeding, judicial or otherwise, with respect
to this Indenture, or for the appointment of a receiver or trustee, or for any
other remedy hereunder, unless

                  (1) an Event of Default with respect to Securities of such
         series shall have occurred and be continuing and such Holder has
         previously given written notice to the Trustee of such continuing Event
         of Default;

                  (2) the Holders of not less than 25% in principal amount of
         the Outstanding Securities of that series shall have made written
         request to the Trustee to institute proceedings in respect of such
         Event of Default in its own name as Trustee hereunder;

                  (3) such Holder or Holders have offered to the Trustee
         reasonable indemnity against the costs, expenses and liabilities to be
         incurred in compliance with such request;

                  (4) the Trustee for 60 days after its receipt of such notice,
         request and offer of indemnity has failed to institute any such
         proceeding; and



                                      -26-

<PAGE>   33


                  (5) no direction inconsistent with such written request has
         been given to the Trustee during such 60-day period by the Holders of a
         majority in principal amount of the Outstanding Securities of that
         series; it being understood and intended that no one or more of such
         Holders shall have any right in any manner whatever by virtue of, or by
         availing of, any provision of this Indenture to affect, disturb or
         prejudice the rights of any other of such Holders, or to obtain or to
         seek to obtain priority or preference over any other of such Holders or
         to enforce any right under this Indenture, except in the manner herein
         provided and for the equal and ratable benefit of all of such Holders.

SECTION 508.   Unconditional Right of Holders to Receive Principal, Premium 
               and Interest.

         Notwithstanding any other provision in this Indenture, the Holder of
any Security shall have the right, which is absolute and unconditional, to
receive payment of the principal of, premium (if any) and (subject to Section
307) interest on or any Additional Amounts with respect to such Security on the
Stated Maturity or Maturities expressed in such Security (or, in the case of
redemption, on the Redemption Date) and to institute suit for the enforcement of
any such payment on or after such respective dates, and such rights shall not be
impaired or affected without the consent of such Holder.

SECTION 509.   Restoration of Rights and Remedies.

         If the Trustee or any Holder of any Security has instituted any
proceeding to enforce any right or remedy under this Indenture and such
proceeding has been discontinued or abandoned for any reason, or has been
determined adversely to the Trustee or to such Holder, then and in every such
case, the Company, the Trustee and the Holders shall, subject to any
determination in such proceeding, be restored severally and respectively to
their former positions hereunder, and thereafter all rights and remedies of the
Trustee and the Holders shall continue as though no such proceeding had been
instituted.

SECTION 510.   Rights and Remedies Cumulative.

         Except as otherwise provided with respect to the replacement or payment
of mutilated, destroyed, lost or stolen Securities in the last paragraph of
Section 306, no right or remedy herein conferred upon or reserved to the Trustee
or to the Holders is intended to be exclusive of any other right or remedy, and
every right and remedy shall, to the extent permitted by law, be cumulative and
in addition to every other right and remedy given hereunder or now or hereafter
existing at law or in equity or otherwise. The assertion or employment of any
right or remedy hereunder, or otherwise, shall not prevent the concurrent
assertion or employment of any other appropriate right or remedy.

SECTION 511.   Delay or Omission Not Waiver.

         No delay or omission of the Trustee or of any Holder of any Securities
to exercise any right or remedy accruing upon any Event of Default shall impair
any such right or remedy or constitute a waiver of any such Event of Default or
an acquiescence therein. Every right and remedy given by this Article Five or by
law to the Trustee or to the Holders may be exercised from time to time, and as
often as may be deemed expedient, by the Trustee or by the Holders, as the case
may be.

SECTION 512.   Control by Holders.

         With respect to Securities of any series, the Holders of a majority in
principal amount of the Outstanding Securities of such series shall have the
right to direct the time, method and place of conducting any proceeding for any
remedy available to the Trustee, or exercising any trust or power conferred on
the Trustee, relating to or arising under an Event of Default described in
clause (1), (2), (3) or (7) of Section 501, and with respect to all Securities
the Holders of a majority in principal amount of all Outstanding Securities
shall have the right to direct the time, method and place of conducting any
remedy available to the Trustee, or exercising any trust or power conferred on
the Trustee, not relating to or arising under such an Event of Default, provided
that in each such case

                  (1) the Trustee shall have the right to decline to follow any
         such direction if the Trustee, being advised by counsel, determines
         that the action so directed may not lawfully be taken or would conflict
         with this 


                                      -27-

<PAGE>   34


         Indenture or if the Trustee in good faith shall, by a Responsible
         Officer, determine that the proceedings so directed would involve it in
         personal liability or be unjustly prejudicial to the Holders not taking
         part in such direction, and

                  (2) the Trustee may take any other action deemed proper by the
         Trustee which is not inconsistent with such direction.

SECTION 513.   Waiver of Past Defaults.

         Subject to Sections 508 and 902, the Holders of a majority in principal
amount of the Outstanding Securities of any series may on behalf of the Holders
of all the Securities of such series waive any past default hereunder with
respect to such series and its consequences, and the Holders of a majority in
principal amount of all Outstanding Securities may on behalf of the Holders of
all Securities waive any other past default hereunder and its consequences,
except in each case a default

                  (1) in the payment of the principal of, premium (if any) or
         interest on or any Additional Amounts with respect to any Security, or

                  (2) in respect of a covenant or provision hereof that under
         Article Nine cannot be modified or amended without the consent of the
         Holder of each Outstanding Security affected.

         Upon any such waiver, such default shall cease to exist, and any Event
of Default arising therefrom shall be deemed to have been cured, for every
purpose of this Indenture; but no such waiver shall extend to any subsequent or
other default or impair any right consequent thereon.

SECTION 514.   Undertaking for Costs.

         All parties to this Indenture agree, and each Holder of any Security by
his acceptance thereof shall be deemed to have agreed, that any court may in its
discretion require, in any suit for the enforcement of any right or remedy under
this Indenture, or in any suit against the Trustee for any action taken or
omitted by it as Trustee, the filing by any party litigant in such suit of an
undertaking to pay the costs of such suit, and that such court may in its
discretion assess reasonable costs, including reasonable attorneys' fees,
against any party litigant in such suit, having due regard to the merits and
good faith of the claims or defenses made by such party litigant. The provisions
of this Section 514 shall not apply to any suit instituted by the Company, by
the Trustee, by any Holder or group of Holders holding in the aggregate more
than 10% in principal amount of the Outstanding Securities of any series, or by
any Holder for the enforcement of the payment of the principal of, premium (if
any) or interest on or any Additional Amounts with respect to any Security on or
after the Stated Maturity or Maturities expressed in such Security (or, in the
case of redemption, on or after the Redemption Date).

SECTION 515.   Waiver of Stay or Extension Laws.

         The Company covenants (to the extent that it may lawfully do so) that
it will not at any time insist upon, or plead, or in any manner whatsoever claim
or take the benefit or advantage of, any stay or extension law wherever enacted,
now or at any time hereafter in force, which may affect the covenants or the
performance of this Indenture; and the Company (to the extent that it may
lawfully do so) hereby expressly waives all benefit or advantage of any such law
and covenants that it will not hinder, delay or impede the execution of any
power herein granted to the Trustee, but will suffer and permit the execution of
every such power as though no such law had been enacted.

                                   ARTICLE SIX

                                   THE TRUSTEE

SECTION 601.   Certain Duties and Responsibilities.


                                      -28-

<PAGE>   35



                  (a) Except during the continuance of an Event of Default with
         respect to the Securities of any series,

                           (1) the Trustee undertakes to perform such duties and
                  only such duties as are specifically set forth in this
                  Indenture, and no implied covenants or obligations shall be
                  read into this Indenture against the Trustee; and

                           (2) in the absence of bad faith on its part, the
                  Trustee may conclusively rely, as to the truth of the
                  statements and the correctness of the opinions expressed
                  therein, upon certificates or opinions furnished to the
                  Trustee and conforming to the requirements of this Indenture;
                  but in the case of any such certificates or opinions that by
                  any provision hereof are specifically required to be furnished
                  to the Trustee, the Trustee shall be under a duty to examine
                  the same to determine whether or not they conform to the
                  requirements of this Indenture.

                  (b) In case an Event of Default has occurred and is continuing
         with respect to the Securities of any series, the Trustee shall
         exercise such of the rights and powers vested in it by this Indenture,
         and use the same degree of care and skill in their exercise, as a
         prudent man would exercise or use under the circumstances in the
         conduct of his own affairs.

                  (c) No provision of this Indenture shall be construed to
         relieve the Trustee from liability for its own negligent action, its
         own negligent failure to act or its own willful misconduct, except that

                           (1) this clause (1) shall not be construed to limit
                  the effect of subsection (a) of this Section 601;

                           (2) the Trustee shall not be liable for any error of
                  judgment made in good faith by a Responsible Officer, unless
                  it shall be proved that the Trustee was negligent in
                  ascertaining the pertinent facts;

                           (3) the Trustee shall not be liable with respect to
                  any action it takes or omits to take in good faith in
                  accordance with the direction of the Holders of a majority in
                  principal amount of the Outstanding Securities of any series
                  or of all series, determined as provided in Section 512,
                  relating to the time, method and place of conducting any
                  proceeding for any remedy available to the Trustee, or
                  exercising any trust or power conferred upon the Trustee,
                  under this Indenture with respect to the Securities of such
                  series; and

                           (4) no provision of this Indenture shall require the
                  Trustee to expend or risk its own funds or otherwise incur any
                  financial liability in the performance of any of its duties
                  hereunder, or in the exercise of any of its rights or powers,
                  if it shall have reasonable grounds for believing that
                  repayment of such funds or adequate indemnity against such
                  risk or liability is not reasonably assured to it.

                  (d) Whether or not therein expressly so provided, every
         provision of this Indenture relating to the conduct or affecting the
         liability of or affording protection to the Trustee shall be subject to
         the provisions of this Section 601.

SECTION 602.   Notice of Defaults.

         Within 90 days after the occurrence of any Default or Event of Default
with respect to the Securities of any series, the Trustee shall give notice of
such Default or Event of Default known to the Trustee to all Holders of
Securities of such series in the manner provided in Section 107, unless such
default shall have been cured or waived; provided, however, that, except in the
case of a Default or Event of Default in the payment of the principal of,
premium (if any) or interest on or any Additional Amounts with respect to any
Security of such series or in the payment of any sinking fund installment with
respect to Securities of such series, the Trustee shall be protected in
withholding such notice if and so long as the board of directors, the executive
committee or a trust committee of directors or Responsible Officers


                                      -29-

<PAGE>   36


of the Trustee in good faith determine that the withholding of such notice is in
the interest of the Holders of Securities of such series; and provided, further,
that in the case of any Default or Event of Default of the character specified
in Section 501(4) with respect to Securities of such series, no such notice to
Holders shall be given until at least 60 days after the occurrence thereof.

SECTION 603.   Certain Rights of Trustee.

         Subject to the provisions of Section 601:

                  (a) the Trustee may rely and shall be protected in acting or
         refraining from acting upon any resolution, certificate, statement,
         instrument, opinion, report, notice, request, direction, consent,
         order, bond, debenture, note, coupon, other evidence of indebtedness or
         other paper or document believed by it to be genuine and to have been
         signed or presented by the proper party or parties;

                  (b) any request or direction of the Company mentioned herein
         shall be sufficiently evidenced by a Company Request or Company Order
         and any resolution of the Board of Directors may be sufficiently
         evidenced by a Board Resolution;

                  (c) whenever in the administration of this Indenture the
         Trustee shall deem it desirable that a matter be proved or established
         prior to taking, suffering or omitting any action hereunder, the
         Trustee (unless other evidence be herein specifically prescribed) may,
         in the absence of bad faith on its part, rely upon an Officers'
         Certificate;

                  (d) the Trustee may consult with counsel and the written
         advice of such counsel or any Opinion of Counsel shall be full and
         complete authorization and protection in respect of any action taken,
         suffered or omitted by it hereunder in good faith and in reliance
         thereon;

                  (e) the Trustee shall be under no obligation to exercise any
         of the rights or powers vested in it by this Indenture at the request
         or direction of any of the Holders pursuant to this Indenture, unless
         such Holders shall have offered to the Trustee reasonable security or
         indemnity against the costs, expenses and liabilities that might be
         incurred by it in compliance with such request or direction;

                  (f) the Trustee shall not be bound to make any investigation
         into the facts or matters stated in any resolution, certificate,
         statement, instrument, opinion, report, notice, request, direction,
         consent, order, bond, debenture, note, coupon, other evidence of
         indebtedness or other paper or document, but the Trustee, in its
         discretion, may make such further inquiry or investigation into such
         facts or matters as it may see fit, and, if the Trustee shall determine
         to make such further inquiry or investigation, it shall be entitled to
         examine the books, records and premises of the Company, personally or
         by agent or attorney;

                  (g) the Trustee may execute any of the trusts or powers
         hereunder or perform any duties hereunder either directly or by or
         through agents or attorneys and, except for any Affiliates of the
         Trustee, the Trustee shall not be responsible for any misconduct or
         negligence on the part of any agent or attorney appointed with due care
         by it hereunder;

                  (h) the Trustee shall not be charged with knowledge of any
         Default or Event of Default with respect to the Securities of any
         series for which it is acting as Trustee unless either (1) a
         Responsible Officer shall have actual knowledge of such Default or
         Event of Default or (2) written notice of such Default or Event of
         Default shall have been given to the Trustee by the Company or any
         other obligor on such Securities or by any Holder of such Securities;
         and

                  (i) the Trustee shall not be liable for any action taken,
         suffered or omitted by it in good faith and believed by it to be
         authorized or within the discretion or rights or powers conferred upon
         it by this Indenture.


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<PAGE>   37


SECTION 604.   Not Responsible for Recitals or Issuance of Securities.

         The recitals contained herein and in the Securities, except the
Trustee's certificates of authentication, shall be taken as the statements of
the Company, and the Trustee assumes no responsibility for their correctness.
The Trustee makes no representations as to the validity or sufficiency of this
Indenture or of the Securities. The Trustee shall not be accountable for the use
or application by the Company of Securities or the proceeds thereof.

SECTION 605.   May Hold Securities.

         The Trustee, any Authenticating Agent, any Paying Agent, any Security
Registrar or any other agent of the Company, in its individual or any other
capacity, may become the owner or pledgee of Securities and, subject to Sections
608 and 613, may otherwise deal with the Company with the same rights it would
have if it were not Trustee, Authenticating Agent, Paying Agent, Security
Registrar or such other agent.

SECTION 606.   Money Held in Trust.

         Money held by the Trustee in trust hereunder need not be segregated
from other funds except to the extent required by law. The Trustee shall be
under no liability for interest on any money received by it hereunder except as
otherwise agreed in writing with the Company.

SECTION 607.   Compensation and Reimbursement.

         The Company agrees

                  (1) to pay to the Trustee from time to time reasonable
         compensation for all services rendered by it hereunder (which
         compensation shall not be limited by any provision of law in regard to
         the compensation of a trustee of an express trust);

                  (2) except as otherwise expressly provided herein, to
         reimburse the Trustee upon its request for all reasonable expenses,
         disbursements and advances incurred or made by the Trustee in
         accordance with any provision of this Indenture (including the
         reasonable compensation and the reasonable expenses and disbursements
         of its agents and counsel), except any such expense, disbursement or
         advance as may be attributable to its negligence or bad faith; and

                  (3) to indemnify the Trustee and each of its directors,
         officers, employees, agents and/or representatives for, and to hold
         each of them harmless against, any loss, liability or expense incurred
         without negligence or bad faith on each of their part, arising out of
         or in connection with the acceptance or administration of the trust or
         trusts hereunder, including the costs and expenses of defending
         themselves against any claim or liability in connection with the
         exercise or performance of any of the Trustees' powers or duties
         hereunder.

         As security for the performance of the obligations of the Company under
this Section 607, the Trustee shall have a lien prior to the Securities on all
property and funds held or collected by the Trustee as such, except funds held
in trust for the payment of principal of, premium (if any) or interest on or any
Additional Amounts with respect to particular Securities.

         Any expenses and compensation for any services rendered by the Trustee
after the occurrence of an Event of Default specified in clause (5) or (6) of
Section 501 shall constitute expenses and compensation for services of
administration under all applicable federal or state bankruptcy, insolvency,
reorganization or other similar laws.

         The provisions of this Section 607 and any lien arising hereunder shall
survive the resignation or removal of the Trustee or the discharge of the
Company's obligations under this Indenture and the termination of this
Indenture.



                                      -31-

<PAGE>   38


SECTION 608.   Disqualification; Conflicting Interests.

         (a) If the Trustee has or shall acquire any conflicting interest, as
defined in this Section 608, with respect to the Securities of any series, it
shall, within 90 days after ascertaining that it has such conflicting interest,
either eliminate such conflicting interest or resign with respect to the
Securities of that series in the manner and with the effect hereinafter
specified in this Article Six.

         (b) In the event that the Trustee shall fail to comply with the
provisions of subsection (a) of this Section 608 with respect to the Securities
of any series, the Trustee shall, within 10 days after the expiration of such
90-day period, transmit by mail to all Holders of Securities of that series, as
their names and addresses appear in the Security Register, notice of such
failure.

         (c) For the purposes of this Section 608, the term "conflicting
interest" shall have the meaning specified in Section 310(b) of the Trust
Indenture Act and the Trustee shall comply with Section 310(b) of the Trust
Indenture Act; provided, that there shall be excluded from the operation of
Section 310 (b) (1) of the Trust Indenture Act with respect to the Securities of
any series any indenture or indentures under which other securities, or
certificates of interest or participation in other securities, of the Company
are outstanding, if the requirements for such exclusion set forth in Section
310(b) (1) of the Trust Indenture Act are met. For purposes of the preceding
sentence, the optional provision permitted by the second sentence of Section 310
(b) (9) of the Trust Indenture Act shall be applicable.

SECTION 609.   Corporate Trustee Required; Eligibility.

         There shall at all times be a Trustee hereunder which shall be a
corporation organized and doing business under the laws of the United States of
America, any State thereof or the District of Columbia, authorized under such
laws to exercise corporate trust powers, having a combined capital and surplus
of at least $50 million and subject to supervision or examination by federal or
state (or the District of Columbia) authority. If such corporation publishes
reports of condition at least annually, pursuant to law or to the requirements
of said supervising or examining authority, then for the purposes of this
Section 609, the combined capital and surplus of such corporation shall be
deemed to be its combined capital and surplus as set forth in its most recent
report of condition so published. If at any time the Trustee shall cease to be
eligible in accordance with the provisions of this Section 609, it shall resign
immediately in the manner and with the effect hereinafter specified in this
Article Six.

         The Indenture shall always have a Trustee who satisfies the
requirements of Sections 310(a)(1), 310(a)(2) and 310(a)(5) of the Trust
Indenture Act.

SECTION 610.   Resignation and Removal; Appointment of Successor.

         (a) No resignation or removal of the Trustee and no appointment of a
successor Trustee pursuant to this Article Six shall become effective until the
acceptance of appointment by the successor Trustee in accordance with the
applicable requirements of Section 611.

         (b) The Trustee may resign at any time with respect to the Securities
of one or more series by giving written notice thereof to the Company. If the
instrument of acceptance by a successor Trustee required by Section 611 shall
not have been delivered to the resigning Trustee within 30 days after the giving
of such notice of resignation, the resigning Trustee may petition any court of
competent jurisdiction for the appointment of a successor Trustee with respect
to the Securities of such series.

         (c) The Trustee may be removed at any time with respect to the
Securities of any series by Act of the Holders of a majority in principal amount
of the Outstanding Securities of such series, delivered to the Trustee and to
the Company.

         (d) If at any time:

                  (1) the Trustee shall fail to comply with Section 608(a) after
         written request therefor by the Company or by any Holder who has been a
         bona fide Holder of a Security for at least six months, or



                                      -32-

<PAGE>   39


                  (2) the Trustee shall cease to be eligible under Section 609
         and shall fail to resign after written request therefor by the Company
         or by any such Holder of Securities, or

                  (3) the Trustee shall become incapable of acting or shall be
         adjudged a bankrupt or insolvent or a receiver of the Trustee or of its
         property shall be appointed or any public officer shall take charge or
         control of the Trustee or of its property or affairs for the purpose of
         rehabilitation, conservation or liquidation,

then, in any such case, (i) the Company by a Board Resolution may remove the
Trustee with respect to all Securities, or (ii) subject to Section 514, any
Holder who has been a bona fide Holder of a Security for at least six months
may, on behalf of himself and all others similarly situated, petition any court
of competent jurisdiction for the removal of the Trustee with respect to all
Securities and the appointment of a successor Trustee or Trustees.

         (e) If the Trustee shall resign, be removed or become incapable of
acting, or if a vacancy shall occur in the office of Trustee for any cause, with
respect to the Securities of one or more series, the Company, by a Board
Resolution, shall promptly appoint a successor Trustee or Trustees with respect
to the Securities of that or those series (it being understood that any such
successor Trustee may be appointed with respect to the Securities of one or more
or all of such series and that at any time there shall be only one Trustee with
respect to the Securities of any particular series) and such successor Trustee
or Trustees shall comply with the applicable requirements of Section 611. If no
successor Trustee with respect to the Securities of any series shall have been
so appointed by the Company and accepted appointment in the manner required by
Section 611, any Holder who has been a bona fide Holder of a Security of such
series for at least six months may, on behalf of himself and all others
similarly situated, petition any court of competent jurisdiction for the
appointment of a successor Trustee with respect to the Securities of such
series.

         (f) The Company shall give notice of each resignation and each removal
of the Trustee with respect to the Securities of any series and each appointment
of a successor Trustee with respect to the Securities of any series by mailing
written notice of such event by first-class mail, postage prepaid, to all
Holders of Securities of such series as their names and addresses appear in the
Security Register. Each notice shall include the name of the successor Trustee
with respect to the Securities of such series and the address of its Corporate
Trust Office.

SECTION 611.   Acceptance of Appointment by Successor.

         (a) In case of the appointment hereunder of a successor Trustee with
respect to all Securities, every such successor Trustee so appointed shall
execute, acknowledge and deliver to the Company and to the retiring Trustee an
instrument accepting such appointment, and thereupon the resignation or removal
of the retiring Trustee shall become effective and such successor Trustee,
without any further act, deed or conveyance, shall become vested with all the
rights, powers, trusts and duties of the retiring Trustee; but, on the request
of the Company or the successor Trustee, such retiring Trustee shall, upon
payment of its charges, execute and deliver an instrument transferring to such
successor Trustee all the rights, powers and trusts of the retiring Trustee and
shall duly assign, transfer and deliver to such successor Trustee all property
and money held by such retiring Trustee hereunder.

         (b) In case of the appointment hereunder of a successor Trustee with
respect to the Securities of one or more (but not all) series, the Company, the
retiring Trustee and each successor Trustee with respect to the Securities of
one or more series shall execute and deliver an indenture supplemental hereto
wherein each successor Trustee shall accept such appointment and which (1) shall
contain such provisions as shall be necessary or desirable to transfer and
confirm to, and to vest in, each successor Trustee all the rights, powers,
trusts and duties of the retiring Trustee with respect to the Securities of that
or those series to which the appointment of such successor Trustee relates, (2)
if the retiring Trustee is not retiring with respect to all Securities, shall
contain such provisions as shall be deemed necessary or desirable to confirm
that all the rights, powers, trusts and duties of the retiring Trustee with
respect to the Securities of that or those series as to which the retiring
Trustee is not retiring shall continue to be vested in the retiring Trustee and
(3) shall add to or change any of the provisions of this Indenture as shall be
necessary to provide for or facilitate the administration of the trusts
hereunder by more than one Trustee, it being understood that nothing herein or
in such supplemental indenture shall constitute such Trustees co-trustees of the
same trust and that each such Trustee shall be trustee of a trust or trusts
hereunder separate and apart from any trust or trusts hereunder administered by
any other such Trustee; and upon the execution and delivery of such supplemental
indenture, the resignation or removal of the retiring Trustee shall become
effective to the extent provided therein and each such successor Trustee,
without any further act,

                                      -33-

<PAGE>   40

deed or conveyance, shall become vested with all the rights, powers, trusts and
duties of the retiring Trustee with respect to the Securities of that or those
series to which the appointment of such successor Trustee relates; but, on
request of the Company or any successor Trustee, such retiring Trustee shall
duly assign, transfer and deliver to such successor Trustee all property and
money held by such retiring Trustee hereunder with respect to the Securities of
that or those series to which the appointment of such successor Trustee relates.

         (c) Upon request of any such successor Trustee, the Company shall
execute any and all instruments for more fully and certainly vesting in and
confirming to such successor Trustee all such rights, powers and trusts referred
to in paragraph (a) or (b) of this Section 611, as the case may be.

         (d) No successor Trustee shall accept its appointment unless at the
time of such acceptance such successor Trustee shall be qualified and eligible
under this Article Six.

SECTION 612.   Merger, Conversion, Consolidation or Succession to Business.

         Any corporation into which the Trustee may be merged or converted or
with which it may be consolidated, or any corporation resulting from any merger,
conversion or consolidation to which the Trustee shall be a party, or any
corporation succeeding to all or substantially all the corporate trust business
of the Trustee, shall be the successor of the Trustee hereunder, provided such
corporation shall be otherwise qualified and eligible under this Article Six,
without the execution or filing of any paper or any further act on the part of
any of the parties hereto. In case any Securities shall have been authenticated,
but not delivered, by the Trustee then in office, any successor by merger,
conversion or consolidation to such authenticating Trustee may adopt such
authentication and deliver the Securities so authenticated with the same effect
as if such successor Trustee had itself authenticated such Securities.

SECTION 613.   Preferential Collection of Claims Against Company.

         The Trustee shall comply with Section 311(a) of the Trust Indenture
Act, excluding any creditor relationship described in Section 311 (b) of the
Trust Indenture Act. A Trustee who has resigned or been removed shall be subject
to Section 311 (a) of the Trust Indenture Act to the extent indicated therein.

SECTION 614.   Appointment of Authenticating Agent.

         The Trustee may appoint an Authenticating Agent or Agents that shall be
authorized to act on behalf of the Trustee to authenticate Securities issued
upon original issue and upon exchange, registration of transfer or partial
redemption or pursuant to Section 306, and Securities so authenticated shall be
entitled to the benefits of this Indenture and shall be valid and obligatory for
all purposes as if authenticated by the Trustee hereunder. Wherever reference is
made in this Indenture to the authentication and delivery of Securities by the
Trustee or the Trustee's certificate of authentication, such reference shall be
deemed to include authentication and delivery on behalf of the Trustee by an
Authenticating Agent and a certificate of authentication executed on behalf of
the Trustee by an Authenticating Agent. Each Authenticating Agent shall be
acceptable to the Company and shall at all times be a corporation organized and
doing business under the laws of the United States of America, any state thereof
or the District of Columbia, having a combined capital and surplus of not less
than $50 million or equivalent amount expressed in a foreign currency and
subject to supervision or examination by federal or state (or the District of
Columbia) authority or authority of such country. If such Authenticating Agent
publishes reports of condition at least annually, pursuant to law or to the
requirements of said supervising or examining authority, then for the purposes
of this Section 614, the combined capital and surplus of such Authenticating
Agent shall be deemed to be its combined capital and surplus as set forth in its
most recent report of condition so published. If at any time an Authenticating
Agent shall cease to be eligible in accordance with the provisions of this
Section 614, such Authenticating Agent shall resign immediately in the manner
and with the effect specified in this Section 614.

         Any corporation into which an Authenticating Agent may be merged or
converted or with which it may be consolidated, or any corporation resulting
from any merger, conversion or consolidation to which such Authenticating Agent
shall be a party, or any corporation succeeding to the corporate agency or
corporate trust business of an Authenticating Agent, shall continue to be an
Authenticating Agent, provided such corporation shall be otherwise 


                                      -34-

<PAGE>   41

eligible under this Section 614, without the execution or filing of any paper or
any further act on the part of the Trustee or the Authenticating Agent.

         An Authenticating Agent may resign at any time by giving written notice
thereof to the Trustee and to the Company. The Trustee may at any time terminate
the agency of an Authenticating Agent by giving written notice thereof to such
Authenticating Agent and to the Company. Upon receiving such a notice of
resignation or upon such a termination, or in case at any time such
Authenticating Agent shall cease to be eligible in accordance with the
provisions of this Section 614, the Trustee may appoint a successor
Authenticating Agent which shall be acceptable to the Company and shall mail
written notice of such appointment by first-class mail, postage prepaid, to all
Holders as their names and addresses appear in the Security Register. Any
successor Authenticating Agent upon acceptance of its appointment hereunder
shall become vested with all the rights, powers and duties of its predecessor
hereunder, with like effect as if originally named as an Authenticating Agent.
No successor Authenticating Agent shall be appointed unless eligible under the
provisions of this Section 614.

         The Company agrees to pay to each Authenticating Agent from time to
time reasonable compensation for its services under this Section 614.

         If an appointment is made pursuant to this Section 614, the Securities
may have endorsed thereon, in addition to the Trustee's certificate of
authentication, an alternate certificate of authentication in the following
form:

         This is one of the Securities of the series designated therein referred
to in the within-mentioned Indenture.

                                        
                                            ----------------------------------- 
                                            As Trustee

                                            By
                                              ---------------------------------
                                                   As Authenticating Agent

                                            By
                                              ---------------------------------
                                                   Authorized Signatory

                  Notwithstanding any provision of this Section 614 to the
contrary, if at any time any Authenticating Agent appointed hereunder with
respect to any series of Securities shall not also be acting as the Security
Registrar hereunder with respect to any series of Securities, then, in addition
to all other duties of an Authenticating Agent hereunder, such Authenticating
Agent shall also be obligated: (i) to furnish to the Security Registrar promptly
all information necessary to enable the Security Registrar to maintain at all
times an accurate and current Security Register; and (ii) prior to
authenticating any Security denominated in a foreign currency, to ascertain from
the Company the units of such foreign currency that are required to be
determined by the Company pursuant to Section 302.

                                  ARTICLE SEVEN

                HOLDER'S LISTS AND REPORTS BY TRUSTEE AND COMPANY

SECTION 701.   Company to Furnish Trustee Names and Addresses of Holders.

         With respect to each series of Securities, the Company will furnish or
cause to be furnished to the Trustee:

         (a) semi-annually, not more than 15 days after each Regular Record Date
relating to that series (or, if there is no Regular Record Date relating to that
series, on January 1 and July 1), a list, in such form as the Trustee may
reasonably require, of the names and addresses of the Holders of that series as
of such dates, and

         (b) at such other times as the Trustee may request in writing, within
30 days after the receipt by the Company of any such request, a list of similar
form and content, such list to be dated as of a date not more than 15 days prior
to the time such list is furnished; provided, that so long as the Trustee is the
Security Registrar, the Company shall



                                      -35-

<PAGE>   42

not be required to furnish or cause to be furnished such a list to the Trustee.
The Company shall otherwise comply with Section 310(a) of the Trust Indenture
Act.

SECTION 702.   Preservation of Information; Communications to Holders.

         (a) The Trustee shall preserve, in as current a form as is reasonably
practicable, the names and addresses of Holders of each series contained in the
most recent list furnished to the Trustee as provided in Section 701 and the
names and addresses of Holders of each series received by the Trustee in its
capacity as Security Registrar. The Trustee may destroy any list furnished to it
as provided in Section 701 upon receipt of a new list so furnished. The Trustee
shall otherwise comply with Section 310(a) of the Trust Indenture Act.

         (b) Holders of Securities may communicate pursuant to Section 312 (b)
of the Trust Indenture Act with other Holders with respect to their rights under
this Indenture or under the Securities. The Company, the Trustee, the Security
Registrar and any other Person shall have the protection of Section 312(c) of
the Trust Indenture Act.

SECTION 703.   Reports by Trustee.

         (a) Within 60 days after May 15 of each year after the execution of
this Indenture, the Trustee shall transmit by mail to Holders a brief report
dated as of such May 15 that complies with Section 313(a) of the Trust Indenture
Act. The Trustee shall comply with Section 313 (b) of the Trust Indenture Act.
The Trustee shall transmit by mail all reports as required by Sections 313(c)
and 313(d) of the Trust Indenture Act.

         (b) A copy of each report pursuant to subsection (a) of this Section
703 shall, at the time of its transmission to Holders, be filed by the Trustee
with each stock exchange upon which any Securities are listed, with the
Commission and with the Company. The Company will notify the Trustee when any
Securities are listed on any stock exchange.

SECTION 704.   Reports by Company.

         The Company shall file with the Trustee, within 15 days after the
Company is required to file the same with the Commission, copies of the annual
reports and of the information, documents and other reports (or copies of such
portions of any of the foregoing as the Commission may from time to time by
rules and regulations prescribe) which the Company may be required to file with
the Commission pursuant to Section 13 or Section 15(d) of the Securities
Exchange Act of 1934, as amended, and shall otherwise comply with Section 314(a)
of the Trust Indenture Act.

                                  ARTICLE EIGHT

              CONSOLIDATION, MERGER, CONVEYANCE, TRANSFER OR LEASE

SECTION 801.   Company May Consolidate, Etc., Only on Certain Terms.

         The Company shall not consolidate with or merge into any other Person
or convey, transfer or lease its properties and assets substantially as an
entirety to any Person, unless:

                  (1) the Person formed by such consolidation or into which the
         Company is merged or the Person which acquires by conveyance or
         transfer, or which leases, the properties and assets of the Company
         substantially as an entirety shall be a corporation, partnership or
         trust, shall be organized and existing under the laws of the United
         States of America, any State thereof or the District of Columbia and
         shall expressly assume, by an indenture supplemental hereto, executed
         and delivered to the Trustee, in form satisfactory to the Trustee, the
         due and punctual payment of the principal of, premium (if any) and
         interest on or any Additional Amounts with respect to all the
         Securities and the performance of every covenant of this Indenture on
         the part of the Company to be performed or observed;

                  (2) immediately after giving effect to such transaction, and
         treating any indebtedness that becomes Indebtedness of the Company or a
         Subsidiary of the Company as a result of such transaction as


                                      -36-

<PAGE>   43

         having been incurred by the Company or such Subsidiary at the time of
         such transaction, no Default or Event of Default, shall have happened
         and be continuing; and

                  (3) the Company has delivered to the Trustee an Officers'
         Certificate and an Opinion of Counsel, each stating that such
         consolidation, merger, conveyance, transfer or lease and, if a
         supplemental indenture is required in connection with such transaction,
         such supplemental indenture comply with this Article Eight and that all
         conditions precedent herein provided for relating to such transaction
         have been complied with.

SECTION 802.   Successor Person Substituted.

         Upon any consolidation by the Company with or merger by the Company
into any other Person or any conveyance, transfer or lease of the properties and
assets of the Company substantially as an entirety in accordance with Section
801, the successor Person formed by such consolidation or into which the Company
is merged or to which such conveyance, transfer or lease is made shall succeed
to, and be substituted for, and may exercise every right and power of, the
Company under this Indenture with the same effect as if such successor Person
had been named as the Company herein, and thereafter, except in the case of such
lease, the predecessor Person shall be relieved of all obligations and covenants
under this Indenture and the Securities.

                                  ARTICLE NINE

                             SUPPLEMENTAL INDENTURES

SECTION 901.   Supplemental Indentures Without Consent of Holders.

         Without the consent of any Holders, the Company, when authorized by a
Board Resolution, and the Trustee, at any time and from time to time, may enter
into one or more indentures supplemental hereto, in form satisfactory to the
Trustee, for any of the following purposes:

                  (1) to evidence the succession of another Person to the
         Company and the assumption by any such successor of the covenants of
         the Company herein and in the Securities; or

                  (2) to add to the covenants of the Company for the benefit of
         the Holders of all or any series of Securities (and if such covenants
         are to be for the benefit of less than all series of Securities,
         stating that such covenants are expressly being included solely for the
         benefit of such series) to convey, transfer, assign, mortgage or pledge
         any property to or with the Trustee or otherwise secure any series of
         the Securities or to surrender any right or power herein conferred upon
         the Company; or

                  (3) to add any additional Events of Default with respect to
         all or any series of the Securities (and, if such Event of Default is
         applicable to less than all series of Securities, specifying the series
         to which such Event of Default is applicable); or

                  (4) to change or eliminate any of the provisions of this
         Indenture, provided that any such change or elimination shall become
         effective only when there is no Security Outstanding of any series
         created prior to the execution of such supplemental indenture which is
         adversely affected by such change in or elimination of such provision;
         or

                  (5) to secure the Securities; or

                  (6) to supplement any of the provisions of this Indenture to
         such extent as shall be necessary to permit or facilitate the
         defeasance and discharge of any series of Securities pursuant to
         Section 401; provided, however, that any such action shall not
         adversely affect the interest of the Holders of Securities of such
         series or any other series of Securities in any material respect; or

                  (7) to establish the form or terms of Securities of any series
         as permitted by Sections 201 and 301; or



                                      -37-

<PAGE>   44



                  (8) to evidence and provide for the acceptance of appointment
         hereunder by a successor Trustee with respect to the Securities of one
         or more series and to add to or change any of the provisions of this
         Indenture as shall be necessary to provide for or facilitate the
         administration of the trusts hereunder by more than one Trustee,
         pursuant to the requirements of Section 611(b); or

                  (9) to cure any ambiguity, to correct or supplement any
         provision herein which may be defective or inconsistent with any other
         provision herein, or to make any other provisions with respect to
         matters or questions arising under this Indenture, provided such other
         provisions as may be made shall not adversely affect the interests of
         the Holders of Securities of any series in any material respect.

SECTION 902.   Supplemental Indentures With Consent of Holders.

         With the consent of the Holders of a majority in principal amount of
the Outstanding Securities of all series affected by such supplemental indenture
(acting as one class), by Act of said Holders delivered to the Company and the
Trustee, the Company, when authorized by a Board Resolution, and the Trustee may
enter into an indenture or indentures supplemental hereto for the purpose of
adding any provisions to or changing in any manner or eliminating any of the
provisions of this Indenture or of modifying in any manner the rights of the
Holders of Securities of such series under this Indenture; provided, however,
that no such supplemental indenture shall, without the consent of the Holder of
each Outstanding Security affected thereby,

                  (1) change the Stated Maturity of the principal of, or any
         installment of principal of or interest on, any Security, or reduce the
         principal amount thereof or the rate of interest thereon, any
         Additional Amounts with respect thereto or any premium payable upon the
         redemption thereof, or change any obligation of the Company to pay
         Additional Amounts (except as contemplated by Section 801(1) and
         permitted by Section 901(1)), or reduce the amount of the principal of
         an Original Issue Discount Security that would be due and payable upon
         a declaration of acceleration of the Maturity thereof pursuant to
         Section 502, or change any Place of Payment where, or the coin or
         currency or currencies (including composite currencies) in which, any
         Security or any premium or any interest thereon or Additional Amounts
         with respect thereto is payable, or impair the right to institute suit
         for the enforcement of any such payment on or after the Stated Maturity
         thereof (or, in the case of redemption, on or after the Redemption
         Date), or modify the provisions of this Indenture with respect to the
         subordination of any Security in a manner adverse to the holder
         thereof,

                  (2) reduce the percentage in principal amount of Outstanding
         Securities, the consent of whose Holders is required for any such
         supplemental indenture, or the consent of whose Holders is required for
         any waiver (of compliance with certain provisions of this Indenture or
         certain defaults hereunder and their consequences) provided for in this
         Indenture, or

                  (3) modify any of the provisions of this Section 902, Section
         513 or Section 1006, except to increase any such percentage or to
         provide with respect to any particular series the right to condition
         the effectiveness of any supplemental indenture as to that series on
         the consent of the Holders of a specified percentage of the aggregate
         principal amount of Outstanding Securities of such series (which
         provision may be made pursuant to Section 301 without the consent of
         any Holder) or to provide that certain other provisions of this
         Indenture cannot be modified or waived without the consent of the
         Holder of each Outstanding Security affected thereby, provided,
         however, that this clause (3) shall not be deemed to require the
         consent of any Holder with respect to changes in the references to "the
         Trustee" and concomitant changes in this Section 902 and Section 1006,
         or the deletion of this proviso, in accordance with the requirements of
         Section 611 (b) and Section 901(7).

A supplemental indenture which changes or eliminates any covenant or other
provision of this Indenture which has expressly been included solely for the
benefit of one or more particular series of Securities, or which modifies the
rights of the Holders of Securities of such series with respect to such covenant
or other provision, shall be deemed not to affect the rights under this
Indenture of the Holders of Securities of any other series.

         It shall not be necessary for any Act of Holders under this Section 902
to approve the particular form of any proposed supplemental indenture, but it
shall be sufficient if such Act shall approve the substance thereof.


                                      -38-

<PAGE>   45


SECTION 903.   Execution of Supplemental Indentures.

         In executing, or accepting the additional trusts created by, any
supplemental indenture permitted by this Article Nine or the modifications
thereby of the trusts created by this Indenture, the Trustee shall be entitled
to receive, and (subject to Section 601) shall be fully protected in relying
upon an Opinion of Counsel stating that the execution of such supplemental
indenture is authorized or permitted by this Indenture. The Trustee may, but
shall not be obligated to, enter into any such supplemental indenture which
affects the Trustee's own rights, duties, immunities or liabilities under this
Indenture or otherwise.

SECTION 904.   Effect of Supplemental Indentures.

         Upon the execution of any supplemental indenture under this Article
Nine, this Indenture shall be modified in accordance therewith, and such
supplemental indenture shall form a part of this Indenture for all purposes; and
every Holder of Securities theretofore or thereafter authenticated and delivered
hereunder shall be bound thereby.

SECTION 905.   Conformity With Trust Indenture Act.

         Every supplemental indenture executed pursuant to this Article Nine
shall conform to the requirements of the Trust Indenture Act as then in effect.

SECTION 906.   Reference in Securities to Supplemental Indentures.

         Securities of any series authenticated and delivered after the
execution of any supplemental indenture pursuant to this Article Nine may, and
shall if required by the Trustee, bear a notation in form approved by the
Trustee as to any matter provided for in such supplemental indenture. If the
Company shall so determine, new Securities of any series so modified as to
conform, in the opinion of the Trustee and the Company, to any such supplemental
indenture may be prepared and executed by the Company and authenticated and
delivered by the Trustee in exchange for Outstanding Securities of such series.

                                   ARTICLE TEN

                                    COVENANTS

SECTION 1001.  Payment of Principal, Premium and Interest.

         The Company covenants and agrees for the benefit of the Holders of each
series of Securities that it will duly and punctually pay the principal of,
premium (if any) and interest on and any Additional Amounts with respect to the
Securities of that series in accordance with the terms of the Securities and
this Indenture.

SECTION 1002.  Maintenance of Office or Agency.

         The Company will maintain in each Place of Payment for any series of
Securities an office or agency where Securities of that series may be presented
or surrendered for payment, where Securities of that series may be surrendered
for registration of transfer or exchange and where notices and demands to or
upon the Company in respect of the Securities of that series and this Indenture
may be served. The Company will give prompt written notice to the Trustee of the
location, and any change in the location, of such office or agency. If at any
time the Company shall fail to maintain any such required office or agency or
shall fail to furnish the Trustee with the address thereof, such presentations,
surrenders, notices and demands may be made or served at the Corporate Trust
Office of the Trustee and the Company hereby appoints the Trustee its agent to
receive all presentations, surrenders, notices and demands.

         The Company may also from time to time designate one or more other
offices or agencies where the Securities of one or more series may be presented
or surrendered for any or all such purposes and may from time to time rescind
such designations; provided, however, that no such designation or rescission
shall in any manner relieve the Company of its obligation to maintain an office
or agency in each Place of Payment for Securities of any series for such
purposes. 



                                      -39-

<PAGE>   46

The Company will give prompt written notice to the Trustee of any such
designation or rescission and of any change in the location of any such other
office or agency.

SECTION 1003.  Money for Securities Payments to be Held in Trust.

         If the Company, any Subsidiary or any of their respective Affiliates
shall at any time act as Paying Agent with respect to any series of Securities,
such Paying Agent will, on or before each due date of the principal of, premium
(if any) or interest on or any Additional Amounts with respect to any of the
Securities of that series, segregate and hold in trust for the benefit of the
Persons entitled thereto a sum sufficient to pay the principal, premium (if any)
or interest or any Additional Amounts so becoming due until such sums shall be
paid to such Persons or otherwise disposed of as herein provided and will
promptly notify the Trustee of its action or failure so to act.

         Whenever the Company shall have one or more Paying Agents for any
series of Securities, the Company will, on or before each due date of the
principal of, premium (if any) or interest on any Securities of that series,
deposit with a Paying Agent a sum sufficient to pay the principal of, premium
(if any) or interest so becoming due, such sum to be held in trust for the
benefit of the Persons entitled to such principal, premium or interest, and
(unless such Paying Agent is the Trustee) the Company will promptly notify the
Trustee of its action or failure so to act.

         The Company will cause each Paying Agent for any series of Securities
other than the Trustee to execute and deliver to the Trustee an instrument in
which such Paying Agent shall agree with the Trustee, subject to the provisions
of this Section 1003, that such Paying Agent will:

         (1) hold all sums held by it for the payment of the principal of,
premium (if any) or interest on or any Additional Amounts with respect to
Securities of that series in trust for the benefit of the Persons entitled
thereto until such sums shall be paid to such Persons or otherwise disposed of
as herein provided;

         (2) give the Trustee notice of any default by the Company (or any other
obligor upon the Securities of that series) in the making of any payment of
principal of, premium (if any) or interest on or any Additional Amounts with
respect to the Securities of that series; and

         (3) at any time during the continuance of any such default, upon the
written request of the Trustee, forthwith pay to the Trustee all sums so held in
trust by such Paying Agent.

         The Company may at any time, for the purpose of obtaining the
satisfaction and discharge of this Indenture or for any other purpose, pay, or
by Company Order direct any Paying Agent to pay, to the Trustee all sums held in
trust by the Company or such Paying Agent, such sums to be held by the Trustee
upon the same trusts as those upon which sums were held by the Company or such
Paying Agent; and, upon such payment by any Paying Agent to the Trustee, such
Paying Agent shall be released from all further liability with respect to such
money.

         Any money deposited with the Trustee or any Paying Agent, or then held
by the Company, in trust for the payment of the principal of, premium (if any)
or interest on or any Additional Amounts with respect to any Security of any
series and remaining unclaimed for three years after such principal of, premium
(if any) or interest on or any Additional Amounts with respect to any Securities
have become due and payable shall, unless otherwise required by mandatory
provisions of applicable escheat, or abandoned or unclaimed property law, be
paid to the Company on Company Request, or (if then held by the Company) shall
be discharged from such trust; and the Holder of such Security shall thereafter,
as an unsecured general creditor, look only to the Company for payment thereof,
and all liability of the Trustee or such Paying Agent with respect to such trust
money, and all liability of the Company as trustee thereof, shall thereupon
cease; provided, however, that the Trustee or such Paying Agent, before being
required to make any such repayment, may at the expense of the Company cause to
be published once, in an Authorized Newspaper in The Borough of Manhattan, The
City of New York and in such other Authorized Newspapers as the Trustee shall
deem appropriate, notice that such money remains unclaimed and that, after a
date specified herein, which shall not be less than 30 days from the date of
such publication, any unclaimed balance of such money then remaining will,
unless otherwise required by mandatory provisions of applicable escheat, or
abandoned or unclaimed property law, be repaid to the Company.



                                      -40-
<PAGE>   47


SECTION 1004.  Existence.

         Subject to Article Eight, the Company will do or cause to be done all
things necessary to preserve and keep in full force and effect its corporate
existence.

SECTION 1005.  Statement by Officers as to Default.

         The Company will deliver to the Trustee, within 120 days after the end
of each fiscal year of the Company ending after the date hereof so long as any
Security is outstanding hereunder, an Officers' Certificate, complying with
Section 314(a)(4) of the Trust Indenture Act and stating that a review of the
activities of the Company during such year and of performance under this
Indenture has been made under the supervision of the signers thereof and whether
or not to the best of their knowledge, based upon such review, the Company is in
default in the performance, observance or fulfillment of any of its covenants
and other obligations under this Indenture, and if the Company shall be in
default, specifying each such default known to them and the nature and status
thereof. One of the officers signing the Officers' Certificate delivered
pursuant to this Section 1005 shall be the principal executive, financial or
accounting officer of the Company.

         For purposes of this Section 1005, such compliance shall be determined
without regard to any period of grace or requirement of notice provided under
this Indenture.

SECTION 1006.  Waiver of Certain Covenants.

         The Company may omit in any particular instance to comply with any
covenant or condition set forth in Sections 1001 through 1005, inclusive, or any
covenant added for the benefit of any series of Securities as contemplated by
Section 301 (unless otherwise specified pursuant to Section 301) if before or
after the time for such compliance the Holders of a majority in principal amount
of the Outstanding Securities of all series affected by such omission (acting as
one class) shall, by Act of such Holders, either waive such compliance in such
instance or generally waive compliance with such covenant or condition, but no
such waiver shall extend to or affect such covenant or condition except to the
extent so expressly waived, and, until such waiver shall become effective, the
obligations of the Company and the duties of the Trustee in respect of any such
covenant or condition shall remain in full force and effect.

SECTION 1007.  Additional Amounts.

         If the Securities of a series expressly provide for the payment of
Additional Amounts, the Company will pay to the Holder of any Security of such
series Additional Amounts as expressly provided therein. Whenever in this
Indenture there is mentioned, in any context, the payment of the principal of,
or premium (if any) or interest on any Security of any series or the net
proceeds received from the sale or exchange of any Security of any series, such
mention shall be deemed to include mention of the payment of Additional Amounts
provided for in this Section 1007 to the extent that, in such context,
Additional Amounts are, were or would be payable in respect thereof pursuant to
the provisions of this Section 1007 and express mention of the payment of
Additional Amounts (if applicable) in any provisions hereof shall not be
construed as excluding Additional Amounts in those provisions hereof where such
express mention is not made.

         If the Securities of a series provide for the payment of Additional
Amounts, at least 10 days prior to the first Interest Payment Date with respect
to that series of Securities (or if the Securities of that series will not bear
interest prior to Maturity, the first day on which a payment of principal and
any premium is made), and at least 10 days prior to each date of payment of
principal and any premium or interest if there has been any change with respect
to the matters set forth in the below-mentioned Officers' Certificate, the
Company shall furnish the Trustee and the Company's principal Paying Agent or
Paying Agents, if other than the Trustee, with an Officers' Certificate
instructing the Trustee and such Paying Agent or Paying Agents whether such
payment of principal of and any premium or interest on the Securities of that
series shall be made to Holders of Securities of that series who are United
States Aliens without withholding for or on account of any tax, assessment or
other governmental charge described in the Securities of that series. If any
such withholding shall be required, then such Officers' Certificate shall
specify by country the amount, if any, required to be withheld on such payments
to such Holders of Securities and the Company will pay to such Paying Agent the
Additional Amounts required by this Section 1007. The Company covenants to
indemnify the Trustee and


                                      -41-

<PAGE>   48


any Paying Agent for, and to hold them harmless against any loss, liability or
expense reasonably incurred without negligence or bad faith on their part
arising out of or in connection with actions taken or omitted by any of them in
reliance on any Officers' Certificate furnished pursuant to this Section 1007.

                                 ARTICLE ELEVEN

                            REDEMPTION OF SECURITIES

SECTION 1101.  Applicability of Article.

         Securities of any series which are redeemable before their Stated
Maturity shall be redeemable in accordance with their terms and (except as
otherwise specified as contemplated by Section 301 for Securities of any series)
in accordance with this Article Eleven.

SECTION 1102.  Election to Redeem; Notice to Trustee.

         Unless otherwise provided with respect to the Securities of a series as
contemplated by Section 301, the election of the Company to redeem any
Securities shall be evidenced by a Board Resolution. In case of any redemption
at the election of the Company of less than all the Securities of any series,
the Company shall, a reasonable period prior to the Redemption Date fixed by the
Company (unless a shorter notice shall be satisfactory to the Trustee), notify
the Trustee of such Redemption Date and of the principal amount of Securities of
such series to be redeemed. In the case of any redemption of Securities prior to
the expiration of any restriction on such redemption provided in the terms of
such Securities or elsewhere in this Indenture, the Company shall furnish the
Trustee with an Officers' Certificate evidencing compliance with such
restriction.

SECTION 1103.  Selection by Trustee of Securities to be Redeemed.

         If less than all the Securities of any series are to be redeemed, the
particular Securities to be redeemed shall be selected not more than 60 days
prior to the Redemption Date by the Trustee, from the Outstanding Securities of
such series not previously called for redemption, by such method as the Trustee
shall deem fair and appropriate and that may provide for the selection for
redemption of portions (equal to the minimum authorized denomination for
Securities of that series or any integral multiple thereof) of the principal
amount of Securities of such series of a denomination larger than the minimum
authorized denomination for Securities of that series or of the principal amount
of global Securities of such series.

         The Trustee shall promptly notify the Company and the Security
Registrar in writing of the Securities selected for redemption and, in the case
of any Securities selected for partial redemption, the principal amount thereof
to be redeemed.

         For all purposes of this Indenture, unless the context otherwise
requires, all provisions relating to the redemption of Securities shall relate,
in the case of any Securities redeemed or to be redeemed only in part, to the
portion of the principal amount of such Securities which has been or is to be
redeemed.

SECTION 1104.  Notice of Redemption.

         Notice of redemption shall be given in the manner provided in Section
107 to each Holder of Securities to be redeemed not less than 30 nor more than
60 days prior to the Redemption Date.

         All notices of redemption shall state:

         (1)      the Redemption Date,

         (2)      the Redemption Price,

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<PAGE>   49

         (3) if less than all the Outstanding Securities of any series are to be
redeemed, the identification (and, in the case of partial redemption, the
principal amounts) of the particular Securities to be redeemed,

         (4) that on the Redemption Date the Redemption Price will become due
and payable upon each such Security to be redeemed and, if applicable, that
interest thereon will cease to accrue on and after said date,

         (5) the place or places where such Securities are to be surrendered 
for payment of the Redemption Price,

         (6) that the redemption is for a sinking fund, if such is the case, and

         (7) the "CUSIP" number, if applicable.

         A notice of redemption as contemplated by Section 107 need not identify
particular Securities to be redeemed. Notice of redemption of Securities to be
redeemed at the election of the Company shall be given by the Company or, at the
Company's request, by the Trustee in the name and at the expense of the Company.

SECTION 1105.  Deposit of Redemption Price.

         On or before 10:00 a.m., New York City time, on any Redemption Date,
the Company shall deposit with the Trustee or with a Paying Agent (or, if the
Company is acting as its own Paying Agent, segregate and hold in trust as
provided in Section 1003) an amount of money sufficient to pay the Redemption
Price of, and (except if the Redemption Date shall be an Interest Payment Date)
accrued interest on, and any Additional Amounts with respect to, all the
Securities which are to be redeemed on that date.

SECTION 1106.  Securities Payable on Redemption Date.

         Notice of redemption having been given as aforesaid, the Securities so
to be redeemed shall, on the Redemption Date, become due and payable at the
Redemption Price therein specified, and from and after such date (unless the
Company shall default in the payment of the Redemption Price and accrued
interest) such Securities shall cease to bear interest. Upon surrender of any
such Security for redemption in accordance with said notice, such Security shall
be paid by the Company at the Redemption Price, together with accrued interest
(and any Additional Amounts) to the Redemption Date; provided, however, that
installments of interest whose Stated Maturity is on or prior to the Redemption
Date shall be payable to the Holders of such Securities, or one or more
Predecessor Securities, registered as such at the close of business on the
relevant Record Dates according to their terms and the provisions of Section
307.

         If any Security called for redemption shall not be so paid upon
surrender thereof for redemption, the principal of and premium (if any) shall,
until paid, bear interest from the Redemption Date at the rate prescribed
therefor in the Security or, in the case of Original Issue Discount Securities,
the Securities' Yield to Maturity.

SECTION 1107.  Securities Redeemed in Part.

         Any Security which is to be redeemed only in part shall be surrendered
at a Place of Payment therefor (with, if the Company or the Trustee so requires,
due endorsement by, or a written instrument of transfer in form satisfactory to
the Company and the Trustee duly executed by, the Holder thereof or his attorney
duly authorized in writing), and the Company shall execute, and the Trustee
shall authenticate and deliver to the Holder of such Security without service
charge, a new Security or Securities of the same series and Stated Maturity, of
any authorized denomination as requested by such Holder, in aggregate principal
amount equal to and in exchange for the unredeemed portion of the principal of
the Security so surrendered.

         Unless otherwise specified as contemplated by Section 301, the Company
and any Affiliate of the Company may at any time purchase or otherwise acquire
Securities in the open market or by private agreement. Such acquisition shall
not operate as or be deemed for any purpose to be a redemption of the
indebtedness represented by such Securities. Any Securities purchased or
acquired by the Company may be delivered to the Trustee and, upon such delivery,
the indebtedness represented thereby shall be deemed to be satisfied. Section
309 shall apply to all Securities so delivered.

                                      -43-

<PAGE>   50

                                 ARTICLE TWELVE

                                  SINKING FUNDS

SECTION 1201.  Applicability of Article.

         The provisions of this Article Twelve shall be applicable to any
sinking fund for the retirement of Securities of a series except as otherwise
specified as contemplated by Section 301 for Securities of such series.

         The minimum amount of any sinking fund payment provided for by the
terms of Securities of any series is herein referred to as a "mandatory sinking
fund payment," and any payment in excess of such minimum amount provided for by
the terms of Securities of any series is herein referred to as an "optional
sinking fund payment". Unless otherwise provided by the terms of Securities of
any series, the cash amount of any sinking fund payment may be subject to
reduction as provided in Section 1202. Each sinking fund payment shall be
applied to the redemption of Securities of any series as provided for by the
terms of Securities of such series.

SECTION 1202.  Satisfaction of Sinking Fund Payments with Securities.

         The Company (1) may deliver Outstanding Securities of a series (other
than any previously called for redemption) and (2) may apply as a credit
Securities of a series which have been redeemed either at the election of the
Company pursuant to the terms of such Securities or through the application of
permitted optional sinking fund payments pursuant to the terms of such
Securities, in each case in satisfaction of all or any part of any sinking fund
payment with respect to the Securities of such series required to be made
pursuant to the terms of such Securities as provided for by the terms of such
series; provided that such Securities have not been previously so credited. Such
Securities shall be received and credited for such purpose by the Trustee at the
Redemption Price specified in such Securities for redemption through operation
of the sinking fund and the amount of such sinking payment shall be reduced
accordingly.

SECTION 1203.  Redemption of Securities for Sinking Fund.

         Not less than 45 days prior (unless a shorter period shall be
satisfactory to the Trustee) to each sinking fund payment date for any series of
Securities, the Company will deliver to the Trustee an Officers' Certificate
specifying the amount of the next ensuing sinking fund payment for that series
pursuant to the terms of that series, the portion thereof, if any, which is to
be satisfied by payment of cash and the portion thereof, if any, which is to be
satisfied by delivery of or by crediting Securities of that series pursuant to
Section 1202 and will also deliver to the Trustee any Securities to be so
delivered. Not less than 30 days before each such sinking fund payment date the
Trustee shall select the Securities to be redeemed upon such sinking fund
payment date in the manner specified in Section 1103 and cause notice of the
redemption thereof to be given in the name of and at the expense of the Company
in the manner provided in Section 1104. Such notice having been duly given, the
redemption of such Securities shall be made upon the terms and in the manner
stated in Sections 1106 and 1107.

                                ARTICLE THIRTEEN

                                  SUBORDINATION

SECTION 1301.  Securities Subordinated to Senior Indebtedness.

         The Company and each Holder of a Security, by his acceptance thereof,
agree that (a) the payment of the principal of, premium (if any) and interest on
and any Additional Amounts with respect to each and all the Securities and (b)
any other payment in respect of the Securities, including on account of the
acquisition or redemption of Securities by the Company, is subordinated, to the
extent and in the manner provided in this Article Thirteen, to the prior payment
in full of all Senior Indebtedness of the Company, whether outstanding at the
date of this Indenture or thereafter created, incurred, assumed or guaranteed,
and that these subordination provisions are for the benefit of the holders of
Senior Indebtedness.

                                      -44-

<PAGE>   51


         This Article Thirteen shall constitute a continuing offer to all
Persons who, in reliance upon such provisions, become holders of, or continue to
hold, Senior Indebtedness, and such provisions are made for the benefit of the
holders of Senior Indebtedness, and such holders are made obligees hereunder and
any one or more of them may enforce such provisions.

SECTION 1302.  No Payment on Securities in Certain Circumstances.

         (a) No payment shall be made by the Company on account of the principal
of, premium (if any) or interest on or any Additional Amounts with respect to
the Securities of any series or to acquire any of such Securities (including any
repurchases of such Securities pursuant to the provisions hereof or thereof at
the option of the Holder of such Securities) for cash or property (other than
Junior Securities of the Company), or on account of any redemption provisions of
such Securities, in the event of default in payment of any principal of, premium
(if any) or interest on any Senior Indebtedness of the Company when the same
becomes due and payable, whether at maturity or at a date fixed for prepayment
or by declaration or otherwise (a "Payment Default"), unless and until such
Payment Default has been cured or waived or otherwise has ceased to exist.

         (b) No payment (by set-off or otherwise) may be made by or on behalf of
the Company on account of the principal of, premium (if any) or interest on or
any Additional Amounts with respect to the Securities of any series or to
acquire any of such Securities (including any repurchases of such Securities
pursuant to the provisions hereof or thereof at the option of the Holder of such
Securities) for cash or property (other than Junior Securities), or on account
of the redemption provisions of such Securities, in the event of any event of
default (other than a Payment Default) with respect to any Designated Senior
Indebtedness permitting the holders of such Designated Senior Indebtedness (or a
trustee or other representative on behalf of the holders thereof) to declare
such Designated Senior Indebtedness due and payable prior to the date on which
it would otherwise have become due and payable, upon written notice thereof to
the Company and the Trustee by any holders of Designated Senior Indebtedness (or
a trustee or other representative on behalf of the holders thereof) (the
"Payment Notice"), unless and until such event of default shall have been cured
or waived or otherwise has ceased to exist; provided, that such payments may not
be prevented pursuant to this Section 1302(b) for more than 179 days after an
applicable Payment Notice has been received by the Trustee unless the Designated
Senior Indebtedness in respect of which such event of default exists has been
declared due and payable in its entirety, in which case no such payment may be
made until such acceleration has been rescinded or annulled or such Designated
Senior Indebtedness has been paid in full. No event of default that existed or
was continuing on the date of any Payment Notice (whether or not such event of
default is on the same issue of Designated Senior Indebtedness) may be made the
basis for the giving of a second Payment Notice, and only one such Payment
Notice may be given in any 365-day period.

         (c) In furtherance of the provisions of Section 1301, in the event
that, notwithstanding the foregoing provisions of this Section 1302, any payment
or distribution of assets of the Company (other than Junior Securities of the
Company) shall be received by the Trustee or the Holders of Securities of any
series at a time when such payment or distribution was prohibited by the
provisions of this Section 1302, then, unless such payment or distribution is no
longer prohibited by this Section 1302, such payment or distribution (subject to
the provisions of Section 1307) shall be received and held in trust by the
Trustee or such Holder or Paying Agent for the benefit of the holders of Senior
Indebtedness of the Company, and shall be paid or delivered by the Trustee or
such Holders or such Paying Agent, as the case may be, to the holders of Senior
Indebtedness of the Company remaining unpaid or unprovided for or their
representative or representatives, or to the trustee or trustees under any
indenture pursuant to which any instruments evidencing such Senior Indebtedness
of the Company may have been issued, ratably, according to the aggregate amounts
remaining unpaid on account of such Senior Indebtedness of the Company held or
represented by each, for application to the payment of all Senior Indebtedness
in full after giving effect to all concurrent payments and distributions to or
for the holders of such Senior Indebtedness.

SECTION 1303.  Securities Subordinated to Prior Payment of All Senior

         Indebtedness on Dissolution, Liquidation or Reorganization.

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<PAGE>   52

         Upon any distribution of assets of the Company or upon any dissolution,
winding up, total or partial liquidation or reorganization of the Company,
whether voluntary or involuntary, in bankruptcy, insolvency, receivership or
similar proceeding or upon assignment for the benefit of creditors:

         (a) the holders of all Senior Indebtedness of the Company shall first
be entitled to receive payments in full before the Holders of Securities of any
series are entitled to receive any payment on account of the principal of,
premium (if any) or interest on or any Additional Amounts with respect to such
Securities (other than Junior Securities of the Company);

         (b) any payment or distribution of assets of the Company of any kind or
character, whether in cash, property or securities (other than Junior Securities
of the Company), to which the Holders of Securities of any series or the Trustee
on behalf of such Holders would be entitled, except for the provisions of this
Article Thirteen, shall be paid by the liquidating trustee or agent or other
Person making such a payment or distribution directly to the holders of such
Senior Indebtedness or their representative, ratably according to the respective
amounts of Senior Indebtedness held or represented by each, to the extent
necessary to make payment in full of all such Senior Indebtedness remaining
unpaid after giving effect to all concurrent payments and distributions to the
holders of such Senior Indebtedness; and

         (c) in the event that, notwithstanding the foregoing, any payment or
distribution of assets of the Company of any kind or character, whether in cash,
property or securities (other than Junior Securities of the Company), shall be
received by the Trustee or the Holders of Securities of any series or any Paying
Agent (or, if the Company or any Affiliate of the Company is acting as its own
Paying Agent, money for any such payment or distribution shall be segregated or
held in trust) on account of the principal of, premium (if any) or interest on
or any Additional Amounts with respect to the Securities of such series before
all Senior Indebtedness of the Company is paid in full, such payment or
distribution (subject to the provisions of Section 1307) shall be received and
held in trust by the Trustee or such Holder or Paying Agent for the benefit of
the holders of such Senior Indebtedness, or their respective representatives,
ratably according to the respective amounts of such Senior Indebtedness held or
represented by each, to the extent necessary to make payment as provided herein
of all such Senior Indebtedness remaining unpaid after giving effect to all
concurrent payments and distributions and all provisions therefor to or for the
holders of such Senior Indebtedness, but only to the extent that as to any
holder of such Senior Indebtedness, as promptly as practical following notice
from the Trustee to the holders of such Senior Indebtedness that such prohibited
payment has been received by the Trustee, Holder(s) or Paying Agent (or has been
segregated as provided above), such holder (or a representative therefor)
notifies the Trustee of the amounts then due and owing on such Senior
Indebtedness, if any, held by such holder and only the amounts specified in such
notices to the Trustee shall be paid to the holders of such Senior Indebtedness.

SECTION 1304.  Subrogation to Rights of Holders of Senior Indebtedness.

         Subject to the payment in full of all Senior Indebtedness of the
Company as provided herein, the Holders of the Securities shall be subrogated
(to the extent of the payments or distributions made to the holders of such
Senior Indebtedness pursuant to the provisions of this Article Thirteen) to the
rights of the holders of such Senior Indebtedness to receive payments or
distributions of assets of the Company applicable to the Senior Indebtedness
until all amounts owing on the Securities shall be paid in full. For the purpose
of such subrogation, no such payments or distributions to the holders of such
Senior Indebtedness by the Company, or by or on behalf of the Holders of the
Securities by virtue of this Article Thirteen, which otherwise would have been
made to such Holders shall, as between the Company and such Holders, be deemed
to be payment by the Company or on account of such Senior Indebtedness, it being
understood that the provisions of this Article Thirteen are and are intended
solely for the purpose of defining the relative rights of the Holders of the
Securities, on the one hand, and the holders of such Senior Indebtedness, on the
other hand.

         If any payment or distribution to which the Holders of the Securities
would otherwise have been entitled but for the provisions of this Article
Thirteen shall have been applied, pursuant to the provisions of this Article
Thirteen, to the payment of amounts payable under Senior Indebtedness of the
Company, then such Holders shall be entitled to receive from the holders of such
Senior Indebtedness any payments or distributions received by such holders of
Senior Indebtedness in excess of the amount sufficient to pay all amounts
payable under or in respect of such Senior Indebtedness in full.

                                      -46-

<PAGE>   53

SECTION 1305.  Obligations of the Company Unconditional.

         Nothing contained in this Article Thirteen or elsewhere in this
Indenture or in the Securities is intended to or shall impair, as between the
Company and the Holders of the Securities of any series, the obligation of the
Company, which is absolute and unconditional, to pay to such Holders the
principal of, premium (if any) and interest on or any Additional Amounts with
respect to the Securities of such series as and when the same shall become due
and payable in accordance with their terms, or is intended to or shall affect
the relative rights of such Holders and creditors of the Company other than the
holders of the Senior Indebtedness, nor shall anything herein or therein prevent
the Trustee or any Holder from exercising all remedies otherwise permitted by
applicable law upon default under this Indenture, subject to the rights, if any,
under this Article Thirteen, of the holders of Senior Indebtedness in respect of
cash, property or securities of the Company received upon the exercise of any
such remedy. Notwithstanding anything to the contrary in this Article Thirteen
or elsewhere in this Indenture or in the Securities, upon any distribution of
assets of the Company referred to in this Article Thirteen, the Trustee, subject
to the provisions of Sections 601 and 603, and the Holders of the Securities
shall be entitled to rely upon any order or decree made by any court of
competent jurisdiction in which such dissolution, winding up, liquidation or
reorganization proceedings are pending, or a certificate of the liquidating
trustee or agent or other Person making any distribution to the Trustee or to
such Holders for the purpose of ascertaining the Persons entitled to participate
in such distribution, the holders of the Senior Indebtedness and other
Indebtedness of the Company, the amount thereof or payable thereon, the amount
or amounts paid or distributed thereon and all other facts pertinent thereto or
to this Article Thirteen so long as such court has been apprised of the
provisions of, or the order, decree or certificate makes reference to, the
provisions of this Article Thirteen.

SECTION 1306.  Trustee Entitled to Assume Payments Not Prohibited in Absence of 
               Notice.

         The Trustee shall not at any time be charged with knowledge of the
existence of any facts that would prohibit the making of any payment to or by
the Trustee unless and until a Responsible Officer of the Trustee or any Paying
Agent shall have received, no later than two Business Days prior to such
payment, written notice thereof from the Company or from one or more holders of
Senior Indebtedness or from any representative therefor and, prior to the
receipt of any such written notice, the Trustee, subject to the provisions of
Sections 601 and 603, shall be entitled in all respects conclusively to assume
that no such fact exists.

SECTION 1307.  Application by Trustee of Amounts Deposited with It.

         Amounts deposited in trust with the Trustee pursuant to and in
accordance with Article Four shall be for the sole benefit of Holders of the
Securities of series for the benefit of which such amounts were deposited, and,
to the extent allocated for the payment of Securities of such series, shall not
be subject to the subordination provisions of this Article Thirteen. Otherwise,
any deposit of assets with the Trustee or the Paying Agent (whether or not in
trust) for the payment of principal of, premium (if any) or interest on or any
Additional Amounts with respect to any Securities shall be subject to the
provisions of Sections 1301, 1302, 1303 and 1304; provided that if prior to two
Business Days preceding the date on which by the terms of this Indenture any
such assets may become distributable for any purpose (including without
limitation, the payment of either principal of, premium (if any) or interest on
or any Additional Amounts with respect to any Security), the Trustee or such
Paying Agent shall not have received with respect to such assets the written
notice provided for in Section 1306, then the Trustee or such Paying Agent shall
have full power and authority to receive such assets and to apply the same to
the purpose for which they were received, and shall not be affected by any
notice to the contrary that may be received by it on or after such date; and
provided further that nothing contained in this Article Thirteen shall prevent
the Company from making, or the Trustee from receiving or applying, any payment
in connection with the redemption of Securities if the first publication of
notice of such redemption (whether by mail or otherwise in accordance with this
Indenture) has been made, and the Trustee has received such payment from the
Company, prior to the occurrence of any of the contingencies specified in
Section 1302 or 1303.

SECTION 1308.  Subordination Rights Not Impaired by Acts or Omissions of the 
               Company or Holders of Senior Indebtedness.

         No right of any present or future holders of any Senior Indebtedness to
enforce subordination provisions contained in this Article Thirteen shall at any
time in any way be prejudiced or impaired by any act or failure to act on the
part of the Company or by any act or failure to act, in good faith, by any such
holder, or by any noncompliance by 

                                      -47-

<PAGE>   54

the Company with the terms of this Indenture, regardless of any knowledge
thereof that any such holder may have or be otherwise charged with. The holders
of Senior Indebtedness may extend, renew, modify or amend the terms of the
Senior Indebtedness or any security therefor and release, sell or exchange such
security and otherwise deal freely with the Company, all without affecting the
liabilities and obligations of the parties to this Indenture or the Holders of
the Securities.

SECTION 1309.  Trustee to Effectuate Subordination of Securities.

         Each Holder of a Security by his acceptance thereof authorizes and
expressly directs the Trustee on his behalf to take such action as may be
necessary or appropriate to effectuate the subordination provisions contained in
this Article Thirteen and to protect the rights of the Holders of the Securities
pursuant to this Indenture, and appoints the Trustee his attorney-in-fact for
such purpose, including, in the event of any dissolution, winding up,
liquidation or reorganization of the Company (whether in bankruptcy, insolvency
or receivership proceedings or upon an assignment for the benefit of creditors
of the Company), the filing of a claim for the unpaid balance of his Securities
in the form required in said proceedings and cause said claim to be approved. If
the Trustee does not file a proper claim or proof of debt in the form required
in such proceeding prior to 30 days before the expiration of the time to file
such claim or claims, then the holders of the Senior Indebtedness or their
representative is hereby authorized to have the right to file and is hereby
authorized to file an appropriate claim for and on behalf of the Holders of said
Securities. Nothing herein contained shall be deemed to authorize the Trustee or
the holders of Senior Indebtedness or their representative to authorize or
consent to or accept or adopt on behalf of any Holder of Securities any plan of
reorganization, arrangement, adjustment or composition affecting the Securities
or the rights of any Holder thereof, or to authorize the Trustee or the holders
of Senior Indebtedness or their representative to vote in respect of the claim
of any Holder of the Securities in any such proceeding.

SECTION 1310.  Right of Trustee to Hold Senior Indebtedness.

         The Trustee in its individual capacity shall be entitled to all of the
rights set forth in this Article Thirteen in respect of any Senior Indebtedness
at any time held by it to the same extent as any other holder of Senior
Indebtedness, and nothing in this Indenture shall be construed to deprive the
Trustee of any of its rights as such holder.

SECTION 1311.  Article Thirteen Not to Prevent Events of Default.

         The failure to make a payment on account of principal of, premium (if
any) or interest on the Securities by reason of any provision of this Article
Thirteen shall not be construed as preventing the occurrence of a Default or an
Event of Default under Section 501 or in any way prevent the Holders of the
Securities from exercising any right hereunder other than the right to receive
payment on the Securities.

SECTION 1312.  No Fiduciary Duty of Trustee to Holders of Senior Indebtedness.

         The Trustee shall not be deemed to owe any fiduciary duty to the
holders of Senior Indebtedness, and shall not be liable to any such holders
(other than for its willful misconduct or negligence) if it shall in good faith
mistakenly pay over or distribute to the Holders of the Securities or the
Company or any other Person, cash, property or securities to which any holders
of Senior Indebtedness shall be entitled by virtue of this Article Thirteen or
otherwise. Nothing in this Section 1312 shall affect the obligation of any other
such Person to hold such payment for the benefit of, and to pay such payment
over to, the holders of Senior Indebtedness or their representative.

SECTION 1313.  Article Applicable to Paying Agent.

         In case at any time any Payment Agent other than the Trustee shall have
been appointed by the Company and be then acting hereunder, the term "Trustee"
as used in this Article Thirteen shall in such case (unless the context shall
otherwise require) be construed as extending to and including such Payment Agent
within its meaning as fully for all intents and purposes as if such Paying Agent
were named in this Article Thirteen in addition to or in place of the Trustee;
provided, however, that this Section 1313 shall not apply to the Company or any
Affiliate of the Company if it or such Affiliate acts as Paying Agent.

                                      -48-

<PAGE>   55

                                ARTICLE FOURTEEN

                        MEETINGS OF HOLDERS OF SECURITIES

SECTION 1401.  Purposes for Which Meetings May Be Called.

         A meeting of Holders of Securities of any or all series may be called
at any time and from time to time pursuant to this Article Fourteen to make,
give or take any request, demand, authorization, direction, notice, consent,
waiver or other action provided by this Indenture to be made, given or taken by
Holders of Securities of such series.

SECTION 1402.  Call, Notice and Place of Meetings.

         (a) The Trustee may at any time call a meeting of Holders of Securities
of any series for any purpose specified in Section 1401, to be held at such time
and at such place in Houston, Texas, in The Borough of Manhattan, The City of
New York, or in any other location as the Trustee shall determine. Notice of
every meeting of Holders of Securities of any series, setting forth the time and
the place of such meeting and in general terms the action proposed to be taken
at such meeting, shall be given, in the manner provided in Section 107, not less
than 20 nor more than 180 days prior to the date fixed for the meeting.

         (b) In case at any time the Company, pursuant to a Board Resolution, or
the Holders of at least 10% in aggregate principal amount of the Outstanding
Securities of any series, shall have requested the Trustee for any such series
to call a meeting of the Holders of Securities of such series for any purpose
specified in Section 1401, by written request setting forth in reasonable detail
the action proposed to be taken at the meeting, and the Trustee shall not have
made the first publication of the notice of such meeting within 30 days after
receipt of such request or shall not thereafter proceed to cause the meeting to
be held as provided herein, then the Company or the Holders of Securities of
such series in the amount above specified, as the case may be, may determine the
time and the place in Houston, Texas, in The Borough of Manhattan, The City of
New York, or in London, for such meeting and may call such meeting for such
purposes by giving notice thereof as provided in subsection (a) of this Section
1402.

SECTION 1403.  Persons Entitled to Vote at Meetings.

         To be entitled to vote at any meeting of Holders of Securities of any
series, a Person shall be (1) a Holder of one or more Outstanding Securities of
such series, or (2) a Person appointed by an instrument in writing as proxy for
a Holder or Holders of one or more Outstanding Securities of such series by such
Holder or Holders. The only Persons who shall be entitled to be present or to
speak at any meeting of Holders of Securities of any series shall be the Persons
entitled to vote at such meeting and their counsel, any representatives of the
Trustee and its counsel and any representatives of the Company and its counsel.

SECTION 1404.  Quorum;  Action.

         The Persons entitled to vote a majority in aggregate principal amount
of the Outstanding Securities of a series shall constitute a quorum for a
meeting of Holders of Securities of such series. In the absence of a quorum
within 30 minutes of the time appointed for any such meeting, the meeting shall,
if convened at the request of Holders of Securities of such series, be
dissolved. In any other case, the meeting may be adjourned for a period of not
less than 10 days as determined by the chairman of the meeting prior to the
adjournment of such meeting. In the absence of a quorum at any such adjourned
meeting, such adjourned meeting may be further adjourned for a period of not
less than 10 days as determined by the chairman of the meeting prior to the
adjournment of such adjourned meeting. Subject to Section 1405(d), notice of the
reconvening of any adjourned meeting shall be given as provided in Section
1402(a), except that such notice need be given only once not less than five days
prior to the date on which the meeting is scheduled to be reconvened. Notice of
the reconvening of an adjourned meeting shall state expressly that Persons
entitled to vote a majority in principal amount of the Outstanding Securities of
such series shall constitute a quorum.

         Except as limited by the proviso to Section 902, any resolution
presented to a meeting or adjourned meeting duly reconvened at which a quorum is
present as aforesaid may be adopted by the affirmative vote of the Holders of a
majority in aggregate principal amount of the Outstanding Securities of that
series; provided, however, that, except as 

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<PAGE>   56

limited by the proviso to Section 902, any resolution with respect to any
request, demand, authorization, direction, notice, consent or waiver which this
Indenture expressly provides may be made, given or taken by the Holders of a
specified percentage that is less than a majority in aggregate principal amount
of the Outstanding Securities of a series may be adopted at a meeting or an
adjourned meeting duly reconvened and at which a quorum is present as aforesaid
by the affirmative vote of the Holders of such specified percentage in aggregate
principal amount of the Outstanding Securities of that series.

         Except as limited by the proviso to Section 902, any resolution passed
or decision taken at any meeting of Holders of Securities of any series duly
held in accordance with this Section 1404 shall be binding on all the Holders of
Securities of such series, whether or not present or represented at the meeting.

SECTION 1405.  Determination of Voting Rights; Conduct and Adjournment of 
               Meetings.

         (a) The holding of Securities shall be proved in the manner specified
in Section 105 and the appointment of any proxy shall be proved in the manner
specified in Section 105. Such regulations may provide that written instruments
appointing proxies, regular on their face, may be presumed valid and genuine
without the proof specified in Section 105 or other proof.

         (b) The Trustee shall, by an instrument in writing, appoint a temporary
chairman of the meeting, unless the meeting shall have been called by the
Company or by Holders of Securities as provided in Section 1402(b), in which
case the Company or the Holders of Securities of the series calling the meeting,
as the case may be, shall appoint a temporary chairman. A permanent chairman and
a permanent secretary of the meeting shall be elected by vote of the Persons
entitled to vote a majority in aggregate principal amount of the Outstanding
Securities of such series represented at the meeting.

         (c) At any meeting each Holder of a Security of such series and each
proxy shall be entitled to one vote for each $ 1,000 principal amount of the
Outstanding Securities of such series held or represented by him; provided,
however, that no vote shall be cast or counted at any meeting in respect of any
Security challenged as not Outstanding and ruled by the chairman of the meeting
to be not Outstanding. The chairman of the meeting shall have no right to vote,
except as a Holder of a Security of such series or as a proxy.

         (d) Any meeting of Holders of Securities of any series duly called
pursuant to Section 1402 at which a quorum is present may be adjourned from time
to time by Persons entitled to vote a majority in aggregate principal amount of
the Outstanding Securities of such series represented at the meeting; and the
meeting may be held as so adjourned without further notice.

SECTION 1406.  Counting Votes and Recording Action of Meetings.

         The vote upon any resolution submitted to any meeting of Holders of
Securities of any series shall be by written ballots on which shall be
subscribed the signatures of the Holders of Securities of such series or of
their representatives by proxy and the principal amounts and serial numbers of
the Outstanding Securities of such series held or represented by them. The
permanent chairman of the meeting shall appoint two inspectors of votes who
shall count all votes cast at the meeting for or against any resolution and who
shall make and file with the secretary of the meeting their verified written
reports in duplicate of all votes cast at the meeting. A record, at least in
duplicate, of the proceedings of each meeting of Holders of Securities of any
series shall be prepared by the secretary of the meeting and there shall be
attached to such record the original reports of the inspectors of votes on any
vote by ballot taken thereat and affidavits by one or more persons having
knowledge of the facts setting forth a copy of the notice of the meeting and
showing that such notice was given as provided in Section 1402 and, if
applicable, Section 1404. Each copy shall be signed and verified by the
affidavits of the permanent chairman and secretary of the meeting and one such
copy shall be delivered to the Company, and another to the Trustee to be
preserved by the Trustee, the latter to have attached thereto the ballots voted
at the meeting. Any record so signed and verified shall be conclusive evidence
of the matters therein stated.


                                      * * *

                                      -50-

<PAGE>   57


         This instrument may be executed in any number of counterparts, each of
which so executed shall be deemed to be an original, but all such counterparts
shall together constitute but one and the same instrument.

         IN WITNESS WHEREOF, the parties hereto have caused this Indenture to be
duly executed, and their respective corporate seals to be hereunto affixed and
attested, all as of the day and year first above written.

                                 NOBLE DRILLING CORPORATION



[CORPORATE SEAL]                 By
                                    -------------------------------------------
                                      Name:
                                            -----------------------------------
                                      Title:
                                             ----------------------------------


                                 CHASE BANK OF TEXAS, NATIONAL ASSOCIATION



[CORPORATE SEAL]                 By
                                    -------------------------------------------
                                      Name:
                                            -----------------------------------
                                      Title:
                                             ----------------------------------




                                      -51-

<PAGE>   1
                                                                    Exhibit 5.1



                     [LETTERHEAD OF THOMPSON & KNIGHT, P.C.]

                                December 7, 1998



Noble Drilling Corporation
10370 Richmond Avenue, Suite 400
Houston, Texas  77042

         Re:      Noble Drilling Corporation Registration Statement on Form S-3

Ladies and Gentlemen:

         We have acted as counsel to Noble Drilling Corporation, a Delaware
corporation (the "Company"), in connection with the preparation and filing of
the Company's Registration Statement on Form S-3 (the "Registration Statement")
to be filed with the Securities and Exchange Commission (the "Commission") on
December 8, 1998 under the Securities Act of 1933, as amended (the "Securities
Act"). The Registration Statement relates to the issuance and sale from time to
time, pursuant to the General Rules and Regulations promulgated under the
Securities Act of $300,000,000 aggregate gross proceeds of (i) debt securities,
which may be either senior (the "Senior Debt Securities") or subordinated (the
"Subordinated Debt Securities" and, together with the Senior Debt Securities,
the "Debt Securities"), (ii) shares of common stock, par value $.10 per share,
of the Company (the "Common Stock"), (iii) shares of preferred stock, par value
$1.00 per share, of the Company (the "Preferred Stock"), which may be issued in
the form of depositary shares evidenced by depositary receipts (the "Depositary
Shares"), (iv) warrants to purchase Debt Securities (the "Debt Warrants"),
shares of Common Stock (the "Common Stock Warrants") and shares of Preferred
Stock (the "Preferred Stock Warrants" and, together with the Debt Warrants and
the Common Stock Warrants, the "Securities Warrants") of the Company, (v) Debt
Securities, Common Stock and Preferred Stock that may be issued upon exercise of
the Securities Warrants and (vi) such indeterminate amount of Offered Securities
(as defined below) as may be issued in exchange for or upon conversion of, as
the case may be, the Offered Securities, with an aggregate initial public
offering price of up to $300,000,000. The Debt Securities, Common Stock,
Preferred Stock, Depositary Shares and Securities Warrants are hereinafter
referred to collectively as the "Offered Securities."

         The Offered Securities will be sold or delivered from time to time as
set forth in the Registration Statement, any amendment thereto, the prospectus
contained therein (the "Prospectus") and supplements to the Prospectus (the
"Prospectus Supplements"). The Senior Debt Securities will be issued under an
Indenture to be entered into between the Company and Chase Bank of Texas,
National Association, as Trustee (the "Senior Indenture"). The Subordinated Debt
Securities will be issued under an Indenture to be entered into between the
Company and the Trustee (the "Subordinated Indenture"). The forms of the Senior
Indenture and Subordinated Indenture (collectively, the "Indentures") are
included as exhibits to the Registration Statement.

         This opinion is delivered in accordance with the requirements of Item
601(b)(5) of Regulation S-K under the Securities Act.

         In connection with this opinion, we have examined originals or copies,
certified or otherwise 


<PAGE>   2
Noble Drilling Corporation
December 7, 1998
Page 2


identified to our satisfaction, of the Registration Statement and such
agreements, certificates of public officials, certificates of trustees,
certificates of officers or other representatives of the Company and others, and
such other documents, certificates and records as we have deemed necessary or
appropriate as a basis for the opinions set forth herein.

         In our examination, we have assumed the legal capacity of all natural
persons, the genuineness of all signatures, the authenticity of all documents
submitted to us as originals, the conformity to original documents of all
documents submitted to us as certified, conformed or photostatic copies and the
authenticity of the originals of such latter documents. In making our
examination of executed documents and documents to be executed, we have assumed
that the parties thereto had or will have the power, corporate, trust or other,
to enter into and perform all obligations thereunder and have also assumed the
due authorization by all requisite action, corporate or other, and execution and
delivery by such parties of such documents and the validity and binding effect
thereof on such parties. As to any facts material to the opinions expressed
herein which were not independently established or verified, we have relied upon
oral or written statements and representations of officers and other
representatives of the Company, trustees and others.

         Based upon the foregoing, and subject to the qualifications and
limitations set forth herein, we are of the opinion that:

         1. The Debt Securities have been duly authorized by the Company and,
         (i) when the Registration Statement has become effective under the
         Securities Act, (ii) when the Indenture or Indentures, as the case may
         be, have been duly executed and delivered by the parties thereto and
         (iii) when the Debt Securities have been duly executed and
         authenticated in accordance with the terms of the Indentures and
         delivered and sold and upon payment in full therefor as contemplated by
         the Registration Statement, such Debt Securities will constitute valid
         and legally binding obligations of the Company enforceable in
         accordance with their terms and entitled to the benefits of such
         Indentures.

         2. The shares of Common Stock being registered under the Registration
         Statement have been duly authorized by the Company and (i) when the
         Registration Statement has become effective under the Act and (ii)
         when the shares of Common Stock have been delivered by the Company
         upon purchase thereof and payment in full therefor as contemplated by
         the Registration Statement, such shares of Common Stock will be
         validly issued, fully paid and nonassessable.

         3. The shares of Preferred Stock being registered under the
         Registration Statement will be duly authorized by the Company, validly
         issued, fully paid and nonassessable when (i) the Registration
         Statement has become effective under the Act, (ii) a certificate of
         designations relating to the series of the Preferred Stock being
         issued, in a form to be included as an exhibit of the Registration
         Statement, has been duly filed with the Secretary of State of Delaware
         and (iii) the shares of Preferred Stock have been delivered by the
         Company upon purchase thereof and payment in full therefor as
         contemplated by the Registration Statement.

         4. The Securities Warrants have been duly authorized by the Company and
         (i) when the Registration Statement has become effective under the Act,
         (ii) upon the execution and delivery of a debt warrant agreement, 
         common stock warrant agreement or preferred stock warrant agreement, as
         the case may be, relating to such Securities Warrants in a form to be
         included as an exhibit to the Registration Statement, and (iii) when 
         such Securities Warrants have been duly executed, countersigned, 
         delivered and sold in the applicable form and as contemplated by the
         Registration Statement, such Securities Warrants will constitute valid
         and

<PAGE>   3
Noble Drilling Corporation
December 7, 1998
Page 3


         legally binding obligations of the Company enforceable against the
         Company in accordance with their terms.

         The opinions expressed above are limited by and subject to the
following qualifications:

         (a) We express no opinion other than as to the federal securities laws
of the United States of America, the laws of the State of New York and the
General Corporation Law of the State of Delaware; provided, however, we have
assumed, without investigation, that the laws of the State of New York are
identical in all respects to the laws of the State of Texas.

         (b) In rendering the opinions expressed herein, we have assumed that no
action heretofore taken by the Board of Directors of the Company in connection
with the matters described or referred to herein will be modified, rescinded or
withdrawn after the date hereof.

         (c) The opinions expressed in paragraphs 1 and 4 above are subject to
the qualification that the validity and binding effect of the Securities and the
Indentures may be limited or affected by (i) bankruptcy, insolvency,
reorganization, fraudulent transfer or conveyance, receivership, moratorium and
other similar laws relating to or affecting creditors' rights generally, (ii)
general principles of equity, regardless of whether applied in a proceeding in
equity or at law and (iii) an implied covenant of good faith and fair dealing.

         We hereby consent to the filing of this opinion with the Commission as
Exhibit 5.1 to the Registration Statement. We also consent to the reference to
our firm under the caption "Legal Matters" in the Registration Statement. In
giving this consent, we do not thereby admit that we are in the category of
persons whose consent is required under Section 7 of the Securities Act or the
Rules and Regulations of the Commission promulgated thereunder. This opinion is
expressed as of the date hereof unless otherwise expressly stated, and we
disclaim any undertaking to advise you of any subsequent changes of the facts
stated or assumed herein or any subsequent changes in applicable law.

                                        Very truly yours,

                                        THOMPSON & KNIGHT, P.C.


                                        By: /s/        David L. Emmons
                                            ----------------------------------
                                                        Shareholder




<PAGE>   1
                                  EXHIBIT 12.1
                                        
                           NOBLE DRILLING CORPORATION
               COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES
                         (Dollar Amounts in Thousands)


<TABLE>
<CAPTION>
                                            NINE MONTHS ENDED  
                                              SEPTEMBER, 30                      YEAR ENDED DECEMBER 31,
                                            -----------------  ------------------------------------------------------------ 
                                                  1998           1997         1996          1995        1994          1993
                                            -----------------  --------     --------     --------     --------     --------
<S>                                         <C>                <C>          <C>          <C>          <C>          <C>
Earnings:            
Income before income taxes and 
extraordinary charge....................(1)    $186,434        $379,613     $101,959     $  4,866     $ 27,195     $ 24,415
            
Add:            
Interest on indebtedness and
  amortization of debt expense 
  and discount..........................          3,402          12,894       18,758       12,156       12,351        8,038
            
Interest component of rent expense......          1,898           2,128        1,668          731          457           --
            
Equity in losses of joint ventures......          2,888             528           --           --           --           --
            
Minority interest.......................             --             256          428          214          169          232
                                               --------        --------     --------     --------     --------     --------
            
      Earnings as adjusted..............       $194,622        $395,419     $122,813     $ 17,967     $ 40,172     $ 32,685
                                               ========        ========     ========     ========     ========     ========
            
Fixed Charges:            
Interest on indebtedness and 
  amortization of debt expense 
  and discount..........................       $  3,402        $ 12,894     $ 18,758     $ 12,156     $ 12,351     $  8,038
            
Capitalized interest....................         10,845           4,218           --           --           --           --
            
Interest component of rent expense......          1,898           2,128        1,668          731          457           --
                                               --------        --------     --------     --------     --------     --------
            
                  Fixed charges ........       $ 16,145        $ 19,240     $ 20,426     $ 12,887     $ 12,808     $  8,038
                                               ========        ========     ========     ========     ========     ========

Ratio of earnings to fixed charges......(2)        12.1            20.6          6.0          1.4          3.1          4.1
                                               ========        ========     ========     ========     ========     ========
</TABLE>            
 
(1) Included in the 1997 amount is a  non-recurring gain of $197,676,000 related
    to the sale of the Company's mat-supported jackup rigs.

(2) Excluding a non-recurring gain of $197,676,000 related to the sale of the
    Company's mat-supported jackup rigs, the ratio of earnings to fixed charges 
    for 1997 was 10.3.

<PAGE>   1
                                                                    Exhibit 23.1

                       CONSENT OF INDEPENDENT ACCOUNTANTS

We hereby consent to the incorporation by reference in the Prospectus
constituting part of this Registration Statement on Form S-3 of our report dated
January 29, 1998 appearing on page 24 of Noble Drilling Corporation's Annual
Report for the year ended December 31, 1997.  We also consent to the reference
to us under the heading "Experts" in such Prospectus.


PRICEWATERHOUSECOOPERS LLP


Houston, Texas
December 7, 1998

<PAGE>   1
                                                                    EXHIBIT 25.1
===============================================================================

                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                            -------------------------

                                    FORM T-1

                       STATEMENT OF ELIGIBILITY UNDER THE
                           TRUST INDENTURE ACT OF 1939
                  OF A CORPORATION DESIGNATED TO ACT AS TRUSTEE

                CHECK IF AN APPLICATION TO DETERMINE ELIGIBILITY
                 OF A TRUSTEE PURSUANT TO SECTION 305(b)(2) ____

                             -----------------------

                    CHASE BANK OF TEXAS, NATIONAL ASSOCIATION
               (Exact name of trustee as specified in its charter)

                                   74-0800980
                     (I.R.S. Employer Identification Number)

     712 MAIN STREET, HOUSTON, TEXAS                           77002
  (Address of principal executive offices)                   (Zip code)

                    LEE BOOCKER, 712 MAIN STREET, 26TH FLOOR
                       HOUSTON, TEXAS 77002 (713) 216-2448
            (Name, address and telephone number of agent for service)

                           NOBLE DRILLING CORPORATION
               (Exact name of obligor as specified in its charter)

               DELAWARE                               73-0374541
   (State or other jurisdiction of                 (I.R.S. Employer
    incorporation or organization)               Identification Number)

       10370 RICHMOND AVENUE
           HOUSTON, TEXAS                                 77042
 (Address of principal executive offices)               (Zip code)

                             SENIOR DEBT SECURITIES
                         (Title of indenture securities)

===============================================================================


<PAGE>   2



ITEM 1.           GENERAL INFORMATION.

         FURNISH THE FOLLOWING INFORMATION AS TO THE TRUSTEE:

         (a)      NAME AND ADDRESS OF EACH EXAMINING OR SUPERVISING
                  AUTHORITY TO WHICH IT IS SUBJECT.

                  Comptroller of the Currency, Washington, D.C.
                  Federal Deposit Insurance Corporation, Washington, D.C.
                  Board of Governors of the Federal Reserve System, Washington,
                  D.C.

         (b)      WHETHER IT IS AUTHORIZED TO EXERCISE CORPORATE TRUST POWERS.

                  The trustee is authorized to exercise corporate trust powers.

ITEM 2.           AFFILIATIONS WITH THE OBLIGOR.

                  IF THE OBLIGOR IS AN AFFILIATE OF THE TRUSTEE, DESCRIBE EACH
                  SUCH AFFILIATION.

                  The obligor is not an affiliate of the trustee. (See Note on 
                  Page 7.)

ITEM 3.           VOTING SECURITIES OF THE TRUSTEE.

                  FURNISH THE FOLLOWING INFORMATION AS TO EACH CLASS OF VOTING
                  SECURITIES OF THE TRUSTEE.

                            COL. A                             COL. B
                        TITLE OF CLASS                  AMOUNT OUTSTANDING

                  Not applicable by virtue of Form T-1 General Instruction
                           B and response to Item 13.

ITEM 4.           TRUSTEESHIPS UNDER OTHER INDENTURES.

                  IF THE TRUSTEE IS A TRUSTEE UNDER ANOTHER INDENTURE UNDER
WHICH ANY OTHER SECURITIES, OR CERTIFICATES OF INTEREST OR PARTICIPATION IN ANY
OTHER SECURITIES, OF THE OBLIGOR ARE OUTSTANDING, FURNISH THE FOLLOWING
INFORMATION:

                  (a)      TITLE OF THE SECURITIES OUTSTANDING UNDER EACH SUCH 
                  OTHER INDENTURE.

                  Not applicable by virtue of Form T-1 General Instruction
                           B and response to Item 13.





<PAGE>   3



ITEM 4. (CONTINUED)

                  (b)      A BRIEF STATEMENT OF THE FACTS RELIED UPON AS A BASIS
                  FOR THE CLAIM THAT NO CONFLICTING INTEREST WITHIN THE MEANING 
                  OF SECTION 310(B)(1) OF THE ACT ARISES AS A RESULT OF THE 
                  TRUSTEESHIP UNDER ANY SUCH OTHER INDENTURE, INCLUDING A 
                  STATEMENT AS TO HOW THE INDENTURE SECURITIES WILL RANK AS 
                  COMPARED WITH THE SECURITIES ISSUED UNDER SUCH OTHER
                  INDENTURE.

                  Not applicable by virtue of Form T-1 General Instruction
                           B and response to Item 13.

ITEM 5.           INTERLOCKING DIRECTORATES AND SIMILAR RELATIONSHIPS WITH 
OBLIGOR OR UNDERWRITERS.

                  IF THE TRUSTEE OR ANY OF THE DIRECTORS OR EXECUTIVE OFFICER OF
THE TRUSTEE IS A DIRECTOR, OFFICER, PARTNER, EMPLOYEE, APPOINTEE, OR
REPRESENTATIVE OF THE OBLIGOR OR OF ANY UNDERWRITER FOR THE OBLIGOR, IDENTIFY
EACH SUCH PERSON HAVING ANY SUCH CONNECTION AND STATE THE NATURE OF EACH SUCH
CONNECTION.

                  Not applicable by virtue of Form T-1 General Instruction
                           B and response to Item 13.

ITEM 6.           VOTING SECURITIES OF THE TRUSTEE OWNED BY THE OBLIGOR OR ITS 
OFFICIALS.

                  FURNISH THE FOLLOWING INFORMATION AS TO THE VOTING SECURITIES
OF THE TRUSTEE OWNED BENEFICIALLY BY THE OBLIGOR AND EACH DIRECTOR, PARTNER AND
EXECUTIVE OFFICER OF THE OBLIGOR.
<TABLE>
<CAPTION>

         COL. A                    COL. B                   COL. C                             COL. D
                                                                                            PERCENTAGE OF
                                                                                          VOTING SECURITIES
                                                                                            REPRESENTED BY
                                                         AMOUNT OWNED                      AMOUNT GIVEN IN
   NAME OF OWNER               TITLE OF CLASS            BENEFICIALLY                          COL. C
   -------------               --------------            ------------                     -----------------

<S>                            <C>                       <C>                              <C>

</TABLE>

   Not applicable by virtue of Form T-1 General Instruction B and response to
Item 13.











<PAGE>   4



ITEM 7.           VOTING SECURITIES OF THE TRUSTEE OWNED BY UNDERWRITERS OR 
THEIR OFFICIALS.

                  FURNISH THE FOLLOWING INFORMATION AS TO THE VOTING SECURITIES
OF THE TRUSTEE OWNED BENEFICIALLY BY EACH UNDERWRITER FOR THE OBLIGOR AND EACH
DIRECTOR, PARTNER AND EXECUTIVE OFFICER OF EACH SUCH UNDERWRITER.

<TABLE>
<CAPTION>

         COL. A                      COL. B                    COL. C                           COL. D
                                                                                             PERCENTAGE OF
                                                                                           VOTING SECURITIES
                                                                                            REPRESENTED BY
                                                            AMOUNT OWNED                    AMOUNT GIVEN IN
   NAME OF OWNER                TITLE OF CLASS              BENEFICIALLY                         COL. C
   ------------                 --------------              ------------                   -----------------
<S>                             <C>                         <C>                           <C>

</TABLE>

   Not applicable by virtue of Form T-1 General Instruction B and response to
Item 13.


ITEM 8.           SECURITIES OF THE OBLIGOR OWNED OR HELD BY THE TRUSTEE.

                  FURNISH THE FOLLOWING INFORMATION AS TO THE SECURITIES OF THE
OBLIGOR OWNED BENEFICIALLY OR HELD AS COLLATERAL SECURITY FOR OBLIGATIONS IN
DEFAULT BY THE TRUSTEE.

<TABLE>
<CAPTION>

         COL. A                      COL. B                   COL. C                   COL. D
                                                          AMOUNT OWNED
                                   WHETHER THE           BENEFICIALLY OR             PERCENT OF
                                   SECURITIES           HELD AS COLLATERAL             CLASS
                                   ARE VOTING             SECURITY FOR              REPRESENTED BY
                                  OR NONVOTING           OBLIGATIONS IN              AMOUNT GIVEN
      TITLE OF CLASS               SECURITIES               DEFAULT                    IN COL. C
      --------------              ------------          ------------------          --------------
<S>                              <C>                   <C>                         <C>

</TABLE>

   Not applicable by virtue of Form T-1 General Instruction B and response
to Item 13.

















<PAGE>   5



ITEM 9.           SECURITIES OF UNDERWRITERS OWNED OR HELD BY THE TRUSTEE.

                  IF THE TRUSTEE OWNS BENEFICIALLY OR HOLDS AS COLLATERAL
SECURITY FOR OBLIGATIONS IN DEFAULT ANY SECURITIES OF AN UNDERWRITER FOR THE
OBLIGOR, FURNISH THE FOLLOWING INFORMATION AS TO EACH CLASS OF SECURITIES OF
SUCH UNDERWRITER ANY OF WHICH ARE SO OWNED OR HELD BY THE TRUSTEE.

<TABLE>
<CAPTION>

         COL. A                     COL. B                      COL. C                      COL. D
                                                             AMOUNT OWNED
                                                            BENEFICIALLY OR               PERCENT OF
                                                           HELD AS COLLATERAL               CLASS
     NAME OF ISSUER                                           SECURITY FOR              REPRESENTED BY
           AND                      AMOUNT                   OBLIGATIONS IN              AMOUNT GIVEN
     TITLE OF CLASS              OUTSTANDING               DEFAULT BY TRUSTEE               IN COL. C
     --------------              -----------               ------------------           --------------

<S>                             <C>                       <C>                          <C>

</TABLE>

   Not applicable by virtue of Form T-1 General Instruction B and response to
Item 13.


ITEM 10.          OWNERSHIP OR HOLDINGS BY THE TRUSTEE OF VOTING
                  SECURITIES OF CERTAIN AFFILIATES OR SECURITY HOLDERS OF THE
                  OBLIGOR.

                  IF THE TRUSTEE OWNS BENEFICIALLY OR HOLDS AS COLLATERAL
SECURITY FOR OBLIGATIONS IN DEFAULT VOTING SECURITIES OF A PERSON WHO, TO THE
KNOWLEDGE OF THE TRUSTEE (1) OWNS 10% OR MORE OF THE VOTING SECURITIES OF THE
OBLIGOR OR (2) IS AN AFFILIATE, OTHER THAN A SUBSIDIARY, OF THE OBLIGOR, FURNISH
THE FOLLOWING INFORMATION AS TO THE VOTING SECURITIES OF SUCH PERSON.

<TABLE>
<CAPTION>

         COL. A                   COL. B                    COL. C                        COL. D
                                                        AMOUNT OWNED
                                                        BENEFICIALLY OR                  PERCENT OF
                                                       HELD AS COLLATERAL                  CLASS
      NAME OF ISSUER                                     SECURITY FOR                  REPRESENTED BY
           AND                     AMOUNT               OBLIGATIONS IN                  AMOUNT GIVEN
      TITLE OF CLASS            OUTSTANDING            DEFAULT BY TRUSTEE                 IN COL. C
      --------------            -----------            -------------------             --------------

<S>                            <C>                    <C>                             <C>

</TABLE>

   Not applicable by virtue of Form T-1 General Instruction B and response to
Item 13.








<PAGE>   6




ITEM 11.          OWNERSHIP OR HOLDINGS BY THE TRUSTEE OF ANY SECURITIES 
                  OF A PERSON OWNING 50% OR MORE OF THE VOTING SECURITIES OF 
                  THE OBLIGOR.

                  IF THE TRUSTEE OWNS BENEFICIALLY OR HOLDS AS COLLATERAL
SECURITY FOR OBLIGATIONS IN DEFAULT ANY SECURITIES OF A PERSON WHO, TO THE
KNOWLEDGE OF THE TRUSTEE, OWNS 50% OR MORE OF THE VOTING SECURITIES OF THE
OBLIGOR, FURNISH THE FOLLOWING INFORMATION AS TO EACH CLASS OF SECURITIES OR
SUCH PERSON ANY OF WHICH ARE SO OWNED OR HELD BY THE TRUSTEE.
<TABLE>
<CAPTION>

         COL. A                     COL. B                      COL. C                     COL. D
                                                            AMOUNT OWNED
                                                           BENEFICIALLY OR              PERCENT OF
                                                          HELD AS COLLATERAL               CLASS
      NAME OF ISSUER                                         SECURITY FOR              REPRESENTED BY
           AND                       AMOUNT                 OBLIGATIONS IN              AMOUNT GIVEN
      TITLE OF CLASS              OUTSTANDING             DEFAULT BY TRUSTEE              IN COL. C
     ---------------              -----------             ------------------           --------------

<S>                               <C>                     <C>                         <C> 

</TABLE>

    Not applicable by virtue of Form T-1 General Instruction B and response to
Item 13.


ITEM 12.          INDEBTEDNESS OF THE OBLIGOR TO THE TRUSTEE.

                  EXCEPT AS NOTED IN THE INSTRUCTIONS, IF THE OBLIGOR IS
INDEBTED TO THE TRUSTEE, FURNISH THE FOLLOWING INFORMATION:

<TABLE>
<CAPTION>

           COL. A               COL. B               COL. C

         NATURE OF             AMOUNT
       INDEBTEDNESS          OUTSTANDING           DATE DUE
       ------------          -----------           ---------
<S>                         <C>                   <C> 

</TABLE>

   Not applicable by virtue of Form T-1 General Instruction B and response
to Item 13.


ITEM 13.          DEFAULTS BY THE OBLIGOR.

         (a) STATE WHETHER THERE IS OR HAS BEEN A DEFAULT WITH RESPECT TO THE
SECURITIES UNDER THIS INDENTURE. EXPLAIN THE NATURE OF ANY SUCH DEFAULT.

         There is not, nor has there been, a default with respect to the
securities under this indenture. (See Note on Page 7.)






<PAGE>   7



ITEM 13. (CONTINUED)

         (b) IF THE TRUSTEE IS A TRUSTEE UNDER ANOTHER INDENTURE UNDER WHICH ANY
SECURITIES, OR CERTIFICATES OF INTEREST OR PARTICIPATION IN ANY OTHER
SECURITIES, OF THE OBLIGOR ARE OUTSTANDING, OR IS TRUSTEE FOR MORE THAN ONE
OUTSTANDING SERIES OF SECURITIES UNDER THE INDENTURE, STATE WHETHER THERE HAS
BEEN A DEFAULT UNDER ANY SUCH INDENTURE OR SERIES, IDENTIFY THE INDENTURE OR
SERIES AFFECTED, AND EXPLAIN THE NATURE OF ANY SUCH DEFAULT.

         There has not been a default under any such indenture or series. (See
 Note on Page 7.)

ITEM 14.           AFFILIATIONS WITH THE UNDERWRITERS.

                  IF ANY UNDERWRITER IS AN AFFILIATE OF THE TRUSTEE, DESCRIBE
EACH SUCH AFFILIATION.

       Not applicable by virtue of Form T-1 General Instruction B and response
to Item 13.

ITEM 15.          FOREIGN TRUSTEE.

                  IDENTIFY THE ORDER OR RULE PURSUANT TO WHICH THE FOREIGN
TRUSTEE IS AUTHORIZED TO ACT AS SOLE TRUSTEE UNDER INDENTURES QUALIFIED OR TO BE
QUALIFIED UNDER THE ACT.

                  Not applicable.

ITEM 16.          LIST OF EXHIBITS.

                  LIST BELOW ALL EXHIBITS FILED AS PART OF THIS STATEMENT OF
ELIGIBILITY.

                  o 1.  A copy of the articles of association of the trustee 
                  now in effect.

                  # 2.  A copy of the certificate of authority of the trustee 
                  to commence business.

                  * 3.  A copy of the certificate of authorization of the 
                  trustee to exercise corporate trust powers issued by the 
                  Board of Governors of the Federal Reserve System under date 
                  of January 21, 1948.

                  + 4.  A copy of the existing bylaws of the trustee.

                    5.  Not applicable.

                    6.  The consent of the United States institutional
                        trustees required by Section 321(b) of the Act.

                  []7.  A copy of the latest report of condition of the
                        trustee published pursuant to law or the requirements of
                        its supervising or examining authority.



<PAGE>   8



                    8. Not applicable.

                    9. Not applicable.

                      NOTE REGARDING INCORPORATED EXHIBITS

         Effective January 20, 1998, the name of the Trustee was changed from
Texas Commerce Bank National Association to Chase Bank of Texas, National
Association. The exhibits incorporated herein by reference, except for Exhibit
7, were filed under the former name of the Trustee.

         o Incorporated by reference to exhibit bearing the same designation and
previously filed with the Securities and Exchange Commission as exhibits to the
Form S-3 File No. 33-56195.

         # Incorporated by reference to exhibit bearing the same designation and
previously filed with the Securities and Exchange Commission as exhibits to the
Form S-3 File No. 33-42814.

         * Incorporated by reference to exhibit bearing the same designation and
previously filed with the Securities and Exchange Commission as exhibits to the
Form S-11 File No. 33-25132.

         + Incorporated by reference to exhibit bearing the same designation and
previously filed with the Securities and Exchange Commission as exhibits to the
Form S-3 File No. 33-65055.

        [] Incorporated by reference to exhibit bearing the same designation
and previously filed with the Securities and Exchange Commission as exhibits to
the Form S-3 File No. 333-52197.

                                      NOTE

                  In as much as this Form T-1 is filed prior to the
ascertainment by the trustee of all facts on which to base responsive answers to
Items 2 and 13, the answers to said Items are based on incomplete information.
Such Items may, however, be considered as correct unless amended by an amendment
to this Form T-1.



<PAGE>   9



                                    SIGNATURE


         PURSUANT TO THE REQUIREMENTS OF THE TRUST INDENTURE ACT OF 1939 THE
TRUSTEE, CHASE BANK OF TEXAS, NATIONAL ASSOCIATION, FORMERLY KNOWN AS TEXAS
COMMERCE BANK NATIONAL ASSOCIATION, A NATIONAL BANKING ASSOCIATION ORGANIZED AND
EXISTING UNDER THE LAWS OF THE UNITED STATES OF AMERICA, HAS DULY CAUSED THIS
STATEMENT OF ELIGIBILITY TO BE SIGNED ON ITS BEHALF BY THE UNDERSIGNED,
THEREUNTO AUTHORIZED, ALL IN THE CITY OF HOUSTON, AND STATE OF TEXAS, ON THE 7th
DAY OF DECEMBER, 1998.

                                         CHASE BANK OF TEXAS, NATIONAL
                                              ASSOCIATION, AS TRUSTEE


                                         By:     /s/ MAURI COWEN
                                            --------------------------------
                                                     Mauri Cowen
                                            Vice President and Trust Officer



























<PAGE>   10


                                                                       EXHIBIT 6



Securities and Exchange Commission
Washington, D.C. 20549

Gentlemen:

         The undersigned is to be the trustee under an Indenture between Noble
Drilling Corporation, a Delaware corporation (the "Company"), and Chase Bank of
Texas, National Association, as Trustee, to be entered into in connection with
the issuance of the Company's Senior Debt Securities.

         In accordance with Section 321(b) of the Trust Indenture Act of 1939,
the undersigned hereby consents that reports of examinations of the undersigned,
made by Federal or State authorities authorized to make such examinations, may
be furnished by such authorities to the Securities and Exchange Commission upon
its request therefor.

                                         Very truly yours,

                                         CHASE BANK OF TEXAS, NATIONAL
                                              ASSOCIATION, as Trustee


                                         By: /s/    MAURI COWEN
                                             ---------------------------
                                                    Mauri Cowen
                                         Vice President and Trust Officer








<PAGE>   1
                                                                    EXHIBIT 25.2

================================================================================

                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                            -------------------------

                                    FORM T-1

                       STATEMENT OF ELIGIBILITY UNDER THE
                           TRUST INDENTURE ACT OF 1939
                  OF A CORPORATION DESIGNATED TO ACT AS TRUSTEE

                CHECK IF AN APPLICATION TO DETERMINE ELIGIBILITY
                 OF A TRUSTEE PURSUANT TO SECTION 305(b)(2) ____

                             -----------------------

                    CHASE BANK OF TEXAS, NATIONAL ASSOCIATION
               (Exact name of trustee as specified in its charter)

                                   74-0800980
                     (I.R.S. Employer Identification Number)

   712 MAIN STREET, HOUSTON, TEXAS                                 77002
(Address of principal executive offices)                         (Zip code)

                    LEE BOOCKER, 712 MAIN STREET, 26TH FLOOR
                       HOUSTON, TEXAS 77002 (713) 216-2448
            (Name, address and telephone number of agent for service)

                           NOBLE DRILLING CORPORATION
               (Exact name of obligor as specified in its charter)

          DELAWARE                                             73-0374541
(State or other jurisdiction of                             (I.R.S. Employer
incorporation or organization)                            Identification Number)

     10370 RICHMOND AVENUE
          HOUSTON, TEXAS                                          77042
(Address of principal executive offices)                        (Zip code)

                          SUBORDINATED DEBT SECURITIES
                         (Title of indenture securities)

================================================================================

<PAGE>   2



ITEM 1.           GENERAL INFORMATION.

         FURNISH THE FOLLOWING INFORMATION AS TO THE TRUSTEE:

         (a)      NAME AND ADDRESS OF EACH EXAMINING OR SUPERVISING AUTHORITY TO
                  WHICH IT IS SUBJECT.

                  Comptroller of the Currency, Washington, D.C. 
                  Federal Deposit Insurance Corporation, Washington, D.C. 
                  Board of Governors of the Federal Reserve System, 
                  Washington, D.C.

         (b)      WHETHER IT IS AUTHORIZED TO EXERCISE CORPORATE TRUST POWERS.

                  The trustee is authorized to exercise corporate trust powers.

ITEM 2.           AFFILIATIONS WITH THE OBLIGOR.

                  IF THE OBLIGOR IS AN AFFILIATE OF THE TRUSTEE, DESCRIBE EACH
                  SUCH AFFILIATION.

                  The obligor is not an affiliate of the trustee. (See Note on
                  Page 7.)

ITEM 3.           VOTING SECURITIES OF THE TRUSTEE.

                  FURNISH THE FOLLOWING INFORMATION AS TO EACH CLASS OF VOTING
                  SECURITIES OF THE TRUSTEE.

                             COL. A                         COL. B
                         TITLE OF CLASS                AMOUNT OUTSTANDING
                         --------------                ------------------

                  Not applicable by virtue of Form T-1 General Instruction B and
                  response to Item 13.

ITEM 4.           TRUSTEESHIPS UNDER OTHER INDENTURES.

                  IF THE TRUSTEE IS A TRUSTEE UNDER ANOTHER INDENTURE UNDER
WHICH ANY OTHER SECURITIES, OR CERTIFICATES OF INTEREST OR PARTICIPATION IN ANY
OTHER SECURITIES, OF THE OBLIGOR ARE OUTSTANDING, FURNISH THE FOLLOWING
INFORMATION:

                  (a)      TITLE OF THE SECURITIES OUTSTANDING UNDER EACH SUCH 
                  OTHER INDENTURE.

                  Not applicable by virtue of Form T-1 General Instruction B and
                  response to Item 13.





<PAGE>   3



ITEM 4. (CONTINUED)

                  (b)      A BRIEF STATEMENT OF THE FACTS RELIED UPON AS A BASIS
                  FOR THE CLAIM THAT NO CONFLICTING INTEREST WITHIN THE MEANING
                  OF SECTION 310(b)(1) OF THE ACT ARISES AS A RESULT OF THE
                  TRUSTEESHIP UNDER ANY SUCH OTHER INDENTURE, INCLUDING A
                  STATEMENT AS TO HOW THE INDENTURE SECURITIES WILL RANK AS
                  COMPARED WITH THE SECURITIES ISSUED UNDER SUCH OTHER
                  INDENTURE.

                  Not applicable by virtue of Form T-1 General Instruction B and
                  response to Item 13.

ITEM 5.           INTERLOCKING DIRECTORATES AND SIMILAR RELATIONSHIPS WITH 
                  OBLIGOR OR UNDERWRITERS.

                  IF THE TRUSTEE OR ANY OF THE DIRECTORS OR EXECUTIVE OFFICER OF
THE TRUSTEE IS A DIRECTOR, OFFICER, PARTNER, EMPLOYEE, APPOINTEE, OR
REPRESENTATIVE OF THE OBLIGOR OR OF ANY UNDERWRITER FOR THE OBLIGOR, IDENTIFY
EACH SUCH PERSON HAVING ANY SUCH CONNECTION AND STATE THE NATURE OF EACH SUCH
CONNECTION.

                  Not applicable by virtue of Form T-1 General Instruction B and
                  response to Item 13.

ITEM 6.           VOTING SECURITIES OF THE TRUSTEE OWNED BY THE OBLIGOR OR ITS 
                  OFFICIALS.

                  FURNISH THE FOLLOWING INFORMATION AS TO THE VOTING SECURITIES
OF THE TRUSTEE OWNED BENEFICIALLY BY THE OBLIGOR AND EACH DIRECTOR, PARTNER AND
EXECUTIVE OFFICER OF THE OBLIGOR.

<TABLE>
<CAPTION>


     COL. A                       COL. B                   COL. C                 COL. D
                                                                               PERCENTAGE OF
                                                                              VOTING SECURITIES
                                                                               REPRESENTED BY
                                                           AMOUNT OWNED        AMOUNT GIVEN IN
   NAME OF OWNER               TITLE OF CLASS              BENEFICIALLY             COL. C
   -------------               --------------              ------------       -----------------
<S>                            <C>                         <C>                <C>


</TABLE>



     Not applicable by virtue of Form T-1 General Instruction B and response to
Item 13.












<PAGE>   4



ITEM 7.           VOTING SECURITIES OF THE TRUSTEE OWNED BY UNDERWRITERS OR 
                  THEIR OFFICIALS.

                  FURNISH THE FOLLOWING INFORMATION AS TO THE VOTING SECURITIES
OF THE TRUSTEE OWNED BENEFICIALLY BY EACH UNDERWRITER FOR THE OBLIGOR AND EACH
DIRECTOR, PARTNER AND EXECUTIVE OFFICER OF EACH SUCH UNDERWRITER.

<TABLE>
<CAPTION>

     COL. A                       COL. B                   COL. C                 COL. D
                                                                               PERCENTAGE OF
                                                                              VOTING SECURITIES
                                                                               REPRESENTED BY
                                                           AMOUNT OWNED        AMOUNT GIVEN IN
   NAME OF OWNER               TITLE OF CLASS              BENEFICIALLY             COL. C
   -------------               --------------              ------------       -----------------
<S>                            <C>                         <C>                <C>


</TABLE>

     Not applicable by virtue of Form T-1 General Instruction B and response to
Item 13.




ITEM 8.           SECURITIES OF THE OBLIGOR OWNED OR HELD BY THE TRUSTEE.

                  FURNISH THE FOLLOWING INFORMATION AS TO THE SECURITIES OF THE
OBLIGOR OWNED BENEFICIALLY OR HELD AS COLLATERAL SECURITY FOR OBLIGATIONS IN
DEFAULT BY THE TRUSTEE.

<TABLE>
<CAPTION>


         COL. A                     COL. B                 COL. C                 COL. D
                                                         AMOUNT OWNED
                                  WHETHER THE           BENEFICIALLY OR          PERCENT OF
                                  SECURITIES           HELD AS COLLATERAL           CLASS
                                  ARE VOTING             SECURITY FOR           REPRESENTED BY
                                 OR NONVOTING           OBLIGATIONS IN           AMOUNT GIVEN
      TITLE OF CLASS              SECURITIES               DEFAULT                  IN COL. C
      --------------             ------------          ------------------       ---------------
<S>                              <C>                   <C>                      <C>


</TABLE>

     Not applicable by virtue of Form T-1 General Instruction B and response to
Item 13.


















<PAGE>   5



ITEM 9.           SECURITIES OF UNDERWRITERS OWNED OR HELD BY THE TRUSTEE.

                  IF THE TRUSTEE OWNS BENEFICIALLY OR HOLDS AS COLLATERAL
SECURITY FOR OBLIGATIONS IN DEFAULT ANY SECURITIES OF AN UNDERWRITER FOR THE
OBLIGOR, FURNISH THE FOLLOWING INFORMATION AS TO EACH CLASS OF SECURITIES OF
SUCH UNDERWRITER ANY OF WHICH ARE SO OWNED OR HELD BY THE TRUSTEE.

<TABLE>
<CAPTION>


         COL. A                 COL. B               COL. C                    COL. D
                                                  AMOUNT OWNED
                                                 BENEFICIALLY OR             PERCENT OF
                                                HELD AS COLLATERAL             CLASS
     NAME OF ISSUER                               SECURITY FOR             REPRESENTED BY
         AND                    AMOUNT           OBLIGATIONS IN             AMOUNT GIVEN
     TITLE OF CLASS           OUTSTANDING       DEFAULT BY TRUSTEE            IN COL. C
     --------------           ------------      ------------------        ------------------
<S>                           <C>               <C>                       <C>


</TABLE>

     Not applicable by virtue of Form T-1 General Instruction B and response to
Item 13.



ITEM 10.          OWNERSHIP OR HOLDINGS BY THE TRUSTEE OF VOTING SECURITIES OF 
                  CERTAIN AFFILIATES OR SECURITY HOLDERS OF THE OBLIGOR.

                  IF THE TRUSTEE OWNS BENEFICIALLY OR HOLDS AS COLLATERAL
SECURITY FOR OBLIGATIONS IN DEFAULT VOTING SECURITIES OF A PERSON WHO, TO THE
KNOWLEDGE OF THE TRUSTEE (1) OWNS 10% OR MORE OF THE VOTING SECURITIES OF THE
OBLIGOR OR (2) IS AN AFFILIATE, OTHER THAN A SUBSIDIARY, OF THE OBLIGOR, FURNISH
THE FOLLOWING INFORMATION AS TO THE VOTING SECURITIES OF SUCH PERSON.

<TABLE>
<CAPTION>


         COL. A                 COL. B               COL. C                    COL. D
                                                  AMOUNT OWNED
                                                 BENEFICIALLY OR             PERCENT OF
                                                HELD AS COLLATERAL             CLASS
     NAME OF ISSUER                               SECURITY FOR             REPRESENTED BY
         AND                    AMOUNT           OBLIGATIONS IN             AMOUNT GIVEN
     TITLE OF CLASS           OUTSTANDING       DEFAULT BY TRUSTEE            IN COL. C
     --------------           ------------      ------------------        ------------------
<S>                           <C>               <C>                       <C>


</TABLE>

     Not applicable by virtue of Form T-1 General Instruction B and response to
Item 13.









<PAGE>   6




ITEM 11.          OWNERSHIP OR HOLDINGS BY THE TRUSTEE OF ANY SECURITIES OF A 
                  PERSON OWNING 50% OR MORE OF THE VOTING SECURITIES OF THE 
                  OBLIGOR.

                  IF THE TRUSTEE OWNS BENEFICIALLY OR HOLDS AS COLLATERAL
SECURITY FOR OBLIGATIONS IN DEFAULT ANY SECURITIES OF A PERSON WHO, TO THE
KNOWLEDGE OF THE TRUSTEE, OWNS 50% OR MORE OF THE VOTING SECURITIES OF THE
OBLIGOR, FURNISH THE FOLLOWING INFORMATION AS TO EACH CLASS OF SECURITIES OR
SUCH PERSON ANY OF WHICH ARE SO OWNED OR HELD BY THE TRUSTEE.

<TABLE>
<CAPTION>


         COL. A                 COL. B               COL. C                    COL. D
                                                  AMOUNT OWNED
                                                 BENEFICIALLY OR             PERCENT OF
                                                HELD AS COLLATERAL             CLASS
     NAME OF ISSUER                               SECURITY FOR             REPRESENTED BY
         AND                    AMOUNT           OBLIGATIONS IN             AMOUNT GIVEN
     TITLE OF CLASS           OUTSTANDING       DEFAULT BY TRUSTEE            IN COL. C
     --------------           ------------      ------------------        ------------------
<S>                           <C>               <C>                       <C>


</TABLE>

     Not applicable by virtue of Form T-1 General Instruction B and response to
Item 13.



ITEM 12.          INDEBTEDNESS OF THE OBLIGOR TO THE TRUSTEE.

                  EXCEPT AS NOTED IN THE INSTRUCTIONS, IF THE OBLIGOR IS
INDEBTED TO THE TRUSTEE, FURNISH THE FOLLOWING INFORMATION:

<TABLE>
<CAPTION>

          COL. A                            COL. B                   COL. C

         NATURE OF                          AMOUNT
        INDEBTEDNESS                      OUTSTANDING               DATE DUE
        ------------                      -----------               --------
<S>                                       <C>                       <C>


</TABLE>


     Not applicable by virtue of Form T-1 General Instruction B and response to
Item 13.



ITEM 13.          DEFAULTS BY THE OBLIGOR.

         (a) STATE WHETHER THERE IS OR HAS BEEN A DEFAULT WITH RESPECT TO THE
SECURITIES UNDER THIS INDENTURE. EXPLAIN THE NATURE OF ANY SUCH DEFAULT.

         There is not, nor has there been, a default with respect to the
securities under this indenture. (See Note on Page 7.)






<PAGE>   7



ITEM 13. (CONTINUED)

         (b) IF THE TRUSTEE IS A TRUSTEE UNDER ANOTHER INDENTURE UNDER WHICH ANY
SECURITIES, OR CERTIFICATES OF INTEREST OR PARTICIPATION IN ANY OTHER
SECURITIES, OF THE OBLIGOR ARE OUTSTANDING, OR IS TRUSTEE FOR MORE THAN ONE
OUTSTANDING SERIES OF SECURITIES UNDER THE INDENTURE, STATE WHETHER THERE HAS
BEEN A DEFAULT UNDER ANY SUCH INDENTURE OR SERIES, IDENTIFY THE INDENTURE OR
SERIES AFFECTED, AND EXPLAIN THE NATURE OF ANY SUCH DEFAULT.

         There has not been a default under any such indenture or series. (See
Note on Page 7.)

ITEM 14.     AFFILIATIONS WITH THE UNDERWRITERS.

             IF ANY UNDERWRITER IS AN AFFILIATE OF THE TRUSTEE, DESCRIBE EACH 
             SUCH AFFILIATION.

       Not applicable by virtue of Form T-1 General Instruction B and response
to Item 13.

ITEM 15.     FOREIGN TRUSTEE.

             IDENTIFY THE ORDER OR RULE PURSUANT TO WHICH THE FOREIGN TRUSTEE IS
AUTHORIZED TO ACT AS SOLE TRUSTEE UNDER INDENTURES QUALIFIED OR TO BE QUALIFIED
UNDER THE ACT.

             Not applicable.

ITEM 16.     LIST OF EXHIBITS.

             LIST BELOW ALL EXHIBITS FILED AS PART OF THIS STATEMENT OF
ELIGIBILITY.

             o   1.  A copy of the articles of association of the trustee now in
             effect.

             #   2.  A copy of the certificate of authority of the trustee to 
             commence business.

             *   3.  A copy of the certificate of authorization of the trustee 
             to exercise corporate trust powers issued by the Board of Governors
             of the Federal Reserve System under date of January 21, 1948.

             +   4.  A copy of the existing bylaws of the trustee.

                 5.  Not applicable.

                 6.  The consent of the United States institutional trustees 
                     required by Section 321(b) of the Act.

             [ ] 7.  A copy of the latest report of condition of the trustee 
                     published pursuant to law or the requirements of its 
                     supervising or examining authority.



<PAGE>   8



                 8.  Not applicable.

                 9.  Not applicable.

                      NOTE REGARDING INCORPORATED EXHIBITS

         Effective January 20, 1998, the name of the Trustee was changed from
Texas Commerce Bank National Association to Chase Bank of Texas, National
Association. The exhibits incorporated herein by reference, except for Exhibit
7, were filed under the former name of the Trustee.

         o     Incorporated by reference to exhibit bearing the same designation
and previously filed with the Securities and Exchange Commission as exhibits to
the Form S-3 File No. 33-56195.

         #     Incorporated by reference to exhibit bearing the same designation
and previously filed with the Securities and Exchange Commission as exhibits to
the Form S-3 File No. 33-42814.

         *     Incorporated by reference to exhibit bearing the same designation
and previously filed with the Securities and Exchange Commission as exhibits to
the Form S-11 File No. 33-25132.

         +     Incorporated by reference to exhibit bearing the same designation
and previously filed with the Securities and Exchange Commission as exhibits to
the Form S-3 File No. 33-65055.

         [ ]   Incorporated by reference to exhibit bearing the same designation
and previously filed with the Securities and Exchange Commission as exhibits to
the Form S-3 File No. 333-52197.

                                      NOTE

               Inasmuch as this Form T-1 is filed prior to the ascertainment by
the trustee of all facts on which to base responsive answers to Items 2 and 13,
the answers to said Items are based on incomplete information. Such Items may,
however, be considered as correct unless amended by an amendment to this Form
T-1.



<PAGE>   9



                                    SIGNATURE


         PURSUANT TO THE REQUIREMENTS OF THE TRUST INDENTURE ACT OF 1939 THE
TRUSTEE, CHASE BANK OF TEXAS, NATIONAL ASSOCIATION, FORMERLY KNOWN AS TEXAS
COMMERCE BANK NATIONAL ASSOCIATION, A NATIONAL BANKING ASSOCIATION ORGANIZED AND
EXISTING UNDER THE LAWS OF THE UNITED STATES OF AMERICA, HAS DULY CAUSED THIS
STATEMENT OF ELIGIBILITY TO BE SIGNED ON ITS BEHALF BY THE UNDERSIGNED,
THEREUNTO AUTHORIZED, ALL IN THE CITY OF HOUSTON, AND STATE OF TEXAS, ON THE 7th
DAY OF DECEMBER, 1998.

                                         CHASE BANK OF TEXAS, NATIONAL
                                            ASSOCIATION, AS TRUSTEE


                                         By:     /s/ MAURI COWEN
                                            ------------------------------------
                                                     Mauri Cowen
                                             Vice President and Trust Officer





<PAGE>   10


                                                                       EXHIBIT 6



Securities and Exchange Commission
Washington, D.C. 20549

Gentlemen:

         The undersigned is to be the trustee under an Indenture between Noble
Drilling Corporation, a Delaware corporation (the "Company"), and Chase Bank of
Texas, National Association, as Trustee, to be entered into in connection with
the issuance of the Company's Subordinated Debt Securities.

         In accordance with Section 321(b) of the Trust Indenture Act of 1939,
the undersigned hereby consents that reports of examinations of the undersigned,
made by Federal or State authorities authorized to make such examinations, may
be furnished by such authorities to the Securities and Exchange Commission upon
its request therefor.

                                          Very truly yours,

                                          CHASE BANK OF TEXAS, NATIONAL
                                              ASSOCIATION, as Trustee


                                          By:      /s/ MAURI COWEN
                                             -----------------------------------
                                                       Mauri Cowen
                                               Vice President and Trust Officer




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