NOBLE DRILLING CORP
8-K, 1999-03-23
DRILLING OIL & GAS WELLS
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<PAGE>   1
                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM 8-K

                                 CURRENT REPORT


                     Pursuant to Section 13 or 15(d) of the
                         Securities Exchange Act of 1934

                          Date of Report: March 1, 1999
                        (Date of earliest event reported)


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

<TABLE>
<S>                                   <C>                                    <C>
         DELAWARE                              0-13857                             73-0374541
(State of incorporation)              (Commission file number)                  (I.R.S. employer
                                                                             identification number)
      10370 RICHMOND AVENUE, SUITE 400
               HOUSTON, TEXAS                                                        77042
(Address of principal executive offices)                                          (Zip code)
</TABLE>


       REGISTRANT'S TELEPHONE NUMBER, INCLUDING AREA CODE: (713) 974-3131



<PAGE>   2

ITEM 5.  OTHER EVENTS.

         Reference is hereby made to the Registrant's Registration Statements on
Form S-3 (File Nos. 333-68507 and 333-72059), filed with the Securities and
Exchange Commission (the "Commission") on December 8, 1998 and February 9, 1999,
respectively, and declared effective thereby on December 11, 1998 and February
12, 1999, respectively (collectively, the "Registration Statements"), pursuant
to which the Registrant registered $400,000,000 aggregate principal amount of
global securities for offer and sale in accordance with applicable provisions of
the Securities Act of 1933, as amended.

         On March 11, 1999, the Registrant entered into an Underwriting
Agreement (the "Underwriting Agreement") with Merrill Lynch & Co., Merrill
Lynch, Pierce, Fenner & Smith Incorporated and Salomon Smith Barney Inc., as
representatives of the several underwriters named therein (collectively, the
"Underwriters"), in connection with the proposed public offering by the
Registrant of senior debt securities covered by the Registration Statements. The
Underwriting Agreement in the form in which it was executed is filed herewith as
Exhibit 1.1.

         The Registrant also entered into an Indenture dated as of March 1,
1999, with Chase Bank of Texas, National Association, as trustee ("Trustee"),
with respect to the senior debt securities to be offered and sold pursuant to
the Underwriting Agreement. A copy of the Indenture in the form in which it was
executed is filed herewith as Exhibit 4.1.

         Pursuant to the Indenture, the Registrant and the Trustee entered into
a First Supplemental Indenture dated as of March 16, 1999, providing for the
issuance of the 2009 Notes and the 2019 Notes (as defined below). A copy of the
First Supplemental Indenture in the form in which it was executed is filed
herewith as Exhibit 4.2.

         Pursuant to the Underwriting Agreement, the Registrant agreed to sell
$150,000,000 aggregate principal amount of the Registrant's 6.95% Senior Notes
due 2009 (the "2009 Notes") and $250,000,000 aggregate principal amount of the
Registrant's 7.50% Senior Notes due 2019 (the "2019 Notes" and, together with
the 2009 Notes, the "Notes"). The Notes were issued and sold by the Registrant
on March 16, 1999, and the net proceeds to the Registrant from the sale of the
Notes were approximately $396,731,000.

ITEM 7.  FINANCIAL STATEMENTS AND EXHIBITS.

         (c)      Exhibits

<TABLE>
<CAPTION>
         Exhibit No.       Description
         -----------       -----------

<S>                        <C>
               1.1                  Underwriting Agreement dated March 11, 1999
                                    among Noble Drilling Corporation and Merrill
                                    Lynch & Co., Merrill Lynch, Pierce, Fenner &
                                    Smith Incorporated and Salomon Smith Barney
                                    Inc., as representatives of the several
                                    underwriters named therein.
</TABLE>



                                      -2-
<PAGE>   3

<TABLE>
<S>                                 <C>
               4.1                  Indenture dated as of March 1, 1999 between
                                    Noble Drilling Corporation and Chase Bank of
                                    Texas, National Association, as trustee.

               4.2                  First Supplemental Indenture dated as of
                                    March 16, 1999, between Noble Drilling
                                    Corporation and Chase Bank of Texas,
                                    National Association, as trustee. 
</TABLE>


                                   SIGNATURES

         Pursuant to the requirements of the Securities Exchange Act of 1934,
the Registrant has duly caused this Report to be signed on its behalf by the
undersigned thereunto duly authorized.


                                           NOBLE DRILLING CORPORATION



March 22, 1999                             By: /s/ Robert D. Campbell
                                               ---------------------------------
                                               Robert D. Campbell
                                               President



                                      -3-
<PAGE>   4

                                INDEX TO EXHIBITS


<TABLE>
<CAPTION>
Exhibit No.       Description
- -----------       -----------

<S>               <C>
      1.1         Underwriting Agreement dated March 11, 1999 between Noble
                  Drilling Corporation and Merrill Lynch & Co., Merrill Lynch,
                  Pierce, Fenner & Smith Incorporated and Salomon Smith Barney
                  Inc., as representatives of the several underwriters named
                  therein.

      4.1         Indenture dated as of March 1, 1999 between Noble Drilling
                  Corporation and Chase Bank of Texas, National Association, as
                  trustee.

      4.2         First Supplemental Indenture dated as of March 16, 1999,
                  between Noble Drilling Corporation and Chase Bank of Texas,
                  National Association, as trustee. 
</TABLE>



<PAGE>   1
                                                                    Exhibit 1.1

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







                           NOBLE DRILLING CORPORATION

                            (A DELAWARE CORPORATION)

                                  $400,000,000
                                       OF

                    $150,000,000 6.95% SENIOR NOTES DUE 2009
                    $250,000,000 7.50% SENIOR NOTES DUE 2019




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

                             UNDERWRITING AGREEMENT

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










Dated: March 11, 1999

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

<PAGE>   2

                               TABLE OF CONTENTS


<TABLE>
<CAPTION>
                                                                            PAGE
                                                                            ----
<S>        <C>                                                             <C>
SECTION 1. Representations and Warranties.................................     2
    (a)    Representations and Warranties by the Company..................     2
           (1)   Compliance with Registration Requirements................     3
           (2)   Incorporated Documents...................................     3
           (3)   Independent Accountants..................................     4
           (4)   Financial Statements.....................................     4
           (5)   No Material Adverse Change in Business...................     4
           (6)   Good Standing of the Company.............................     4
           (7)   Good Standing of Subsidiaries............................     5
           (8)   Capitalization...........................................     5
           (9)   Authorization of this Underwriting Agreement.............     5
           (10)  Authorization of the Underwritten Securities.............     5
           (11)  Authorization of the Indenture...........................     6
           (12)  Descriptions of the Underwritten Securities and
                 Indenture................................................     6
           (13)  Absence of Defaults and Conflicts........................     6
           (14)  Absence of Labor Dispute.................................     7
           (15)  Absence of Proceedings...................................     7
           (16)  Accuracy of Exhibits.....................................     7
           (17)  Absence of Further Requirements..........................     7
           (18)  Possession of Intellectual Property......................     8
           (19)  Possession of Licenses and Permits.......................     8
           (20)  Title to Property........................................     8
           (21)  Commodity Exchange Act...................................     8
           (22)  Investment Company Act...................................     9
           (23)  Environmental Laws.......................................     9
    (b)    Officer's Certificates.........................................     9

SECTION 2. Sale and Delivery to Underwriters; Closing.....................     9
    (a)    Underwritten Securities........................................     9
    (b)    Payment........................................................    10
    (c)    Denominations; Registration....................................    10

SECTION 3. Covenants of the Company.......................................    10
    (a)    Compliance with Securities Regulations and Commission 
           Requests.......................................................    10
    (b)    Filing of Amendments...........................................    11
    (c)    Delivery of Registration Statements............................    11
    (d)    Delivery of Prospectuses.......................................    11
    (e)    Continued Compliance with Securities Laws......................    11
    (f)    Blue Sky Qualifications........................................    12
    (g)    Earnings Statement.............................................    12
    (h)    Tender Offer and Consent Solicitation..........................    12
</TABLE>


                                       i
<PAGE>   3

<TABLE>
<S>         <C>                                                            <C>
    (i)     Use of Proceeds...............................................    13
    (j)     Restriction on Sale of Securities.............................    13
    (k)     Reporting Requirements........................................    13

SECTION 4.  Payment of Expenses...........................................    13
    (a)     Expenses......................................................    13
    (b)     Termination of Agreement......................................    13

SECTION 5.  Conditions of Underwriters' Obligations.......................    14
    (a)     Effectiveness of Registration Statement.......................    14
    (b)     Opinion of Counsel for Company................................    14
    (c)     Opinion of Counsel for Underwriters...........................    14
    (d)     Officers' Certificate.........................................    15
    (e)     Accountant's Comfort Letter...................................    15
    (f)     Bring-down Comfort Letter.....................................    15
    (g)     Ratings.......................................................    15
    (h)     No Objection..................................................    16
    (i)     Additional Documents..........................................    16
    (j)     Termination of this Underwriting Agreement....................    16

SECTION 6.  Indemnification...............................................    16
    (a)     Indemnification of Underwriters...............................    16
    (b)     Indemnification of Company, Directors and Officers............    17
    (c)     Actions against Parties; Notification.........................    17
    (d)     Settlement without Consent if Failure to Reimburse............    18

SECTION 7.  Contribution..................................................    19

SECTION 8.  Representations, Warranties and Agreements to Survive
            Delivery......................................................    20

SECTION 9.  Termination...................................................    20
    (a)     Underwriting Agreement........................................    20
    (b)     Liabilities...................................................    21

SECTION 10. Default by One or More of the Underwriters....................    21

SECTION 11. Notices.......................................................    21

SECTION 12. Parties.......................................................    22

SECTION 13. GOVERNING LAW.................................................    22

SECTION 14. Effect of Headings............................................    22
</TABLE>


                                      ii

<PAGE>   4

                           NOBLE DRILLING CORPORATION
                            (a Delaware corporation)

                                  $400,000,000
                                       of
                    $150,000,000 6.95% Senior Notes due 2009
                    $250,000,000 7.50% Senior Notes due 2019


                             UNDERWRITING AGREEMENT


MERRILL LYNCH & CO.
SALOMON SMITH BARNEY
c/o Merrill Lynch, Pierce, Fenner & Smith
              Incorporated
North Tower
World Financial Center
New York, New York  10281-1209

Ladies and Gentlemen:

     Noble Drilling Corporation, a Delaware corporation (the "Company"),
confirms its agreement with Salomon Smith Barney Inc. ("Salomon") and Merrill
Lynch & Co. and Merrill Lynch, Pierce, Fenner & Smith Incorporated ("Merrill
Lynch") and each of the other underwriters named in Schedule A-1 and A-2 hereto
(collectively, the "Underwriters", which term shall also include any
underwriter substituted as hereinafter provided in Section 10 hereof), for whom
Merrill Lynch and Salomon are acting as joint bookrunners (in such capacity,
the "Representatives"), with respect to the issue and sale by the Company and
the purchase by the Underwriters, acting severally and not jointly, of (a)
$150,000,000 aggregate principal amount of the Company's 6.95% Senior Notes due
2009 (the "2009 Notes") in the respective principal amounts set forth in
Schedule A-1 hereof and (b) $250,000,000 aggregate principal amount of the
Company's 7.50% Senior Notes due 2019 (the "2019 Notes") in the respective
principal amounts set forth in Schedule A-2 hereof (collectively, the
"Underwritten Securities"). The Underwritten Securities are to be issued
pursuant to an indenture dated as of March 1, 1999 (the "Indenture") between
the Company and Chase Bank of Texas, National Association, as trustee (the
"Trustee"). The term "Indenture," as used herein, includes the First
Supplemental Indenture dated March 16, 1999, which supplants, modifies and
amends the Indenture and establishes the form and terms of the Underwritten
Securities pursuant to Section 901 of the Indenture.

     The Company understands that the Underwriters propose to make a public
offering of the Underwritten Securities as soon as the Representatives deem
advisable after this Underwriting 

<PAGE>   5

Agreement has been executed and delivered and the Indenture has been qualified
under the Trust Indenture Act of 1939, as amended (the "1939 Act").

     The Company has filed with the Securities and Exchange Commission (the
"Commission") two registration statements on Form S-3 (No. 333-72059 and No.
333-68507) for the registration of the Underwritten Securities under the
Securities Act of 1933, as amended (the "1933 Act"), and the offering thereof
from time to time in accordance with Rule 415 of the rules and regulations of
the Commission under the 1933 Act (the "1933 Act Regulations"). Such
registration statements have been declared effective by the Commission and the
Indenture has been duly qualified under the 1939 Act, and the Company has filed
such post-effective amendments thereto as may be required and each such
post-effective amendment has been declared effective by the Commission. Such
registration statements (as so amended, if applicable), including the
information, if any, deemed to be a part thereof pursuant to Rule 430A(b) of
the 1933 Act Regulations (the "Rule 430A Information") are referred to herein
collectively as the "Registration Statement"; and the final prospectus and the
final prospectus supplement relating to the offering of the Underwritten
Securities, in the forms first furnished to the Underwriters by the Company for
use in connection with the offering of the Underwritten Securities, are
collectively referred to herein as the "Prospectus"; provided, however, that
all references to the "Registration Statement" and the "Prospectus" shall also
be deemed to include all documents incorporated therein by reference pursuant
to the Securities Exchange Act of 1934, as amended (the "1934 Act"). A
"preliminary prospectus" shall be deemed to refer to (i) any prospectus used
before the Registration Statement became effective and (ii) any prospectus that
omitted, as applicable, the Rule 430A Information or other information to be
included upon pricing in a form of prospectus filed with the Commission
pursuant to Rule 424(b) of the 1933 Act Regulations and was used after such
effectiveness and prior to the initial delivery of the Prospectus to the
Underwriters by the Company. For purposes of this Underwriting Agreement, all
references to the Registration Statement, Prospectus or preliminary prospectus
or to any amendment or supplement to any of the foregoing shall be deemed to
include any copy filed with the Commission pursuant to its Electronic Data
Gathering, Analysis and Retrieval system ("EDGAR").

     All references in this Underwriting Agreement to financial statements and
schedules and other information which is "contained," "included" or "stated"
(or other references of like import) in the Registration Statement, Prospectus
or preliminary prospectus shall be deemed to mean and include all such
financial statements and schedules and other information which is incorporated
by reference in the Registration Statement, Prospectus or preliminary
prospectus, as the case may be; and all references in this Underwriting
Agreement to amendments or supplements to the Registration Statement,
Prospectus or preliminary prospectus shall be deemed to include the filing of
any document under the 1934 Act which is incorporated by reference in the
Registration Statement, prospectus or preliminary prospectus, as the case may
be.

     SECTION 1. Representations and Warranties.

     (a) Representations and Warranties by the Company. The Company represents
and warrants to each Underwriter, as of the date hereof and as of the Closing
Time referred to in Section 

                                       2
<PAGE>   6

2(b) hereof, as follows:

          (1) Compliance with Registration Requirements. The Company meets the
     requirements for use of Form S-3 under the 1933 Act. The Registration
     Statement has become effective under the 1933 Act and no stop order
     suspending the effectiveness of the Registration Statement has been issued
     under the 1933 Act and no proceedings for that purpose have been
     instituted or are pending or, to the knowledge of the Company, are
     contemplated by the Commission, and any request on the part of the
     Commission for additional information has been complied with. In addition,
     the Indenture has been duly qualified under the 1939 Act.

          At the respective times the Registration Statement and any
     post-effective amendments thereto (including the filing of the Company's
     most recent Annual Report on Form 10-K with the Commission (the "Annual
     Report on Form 10-K")) became effective and at the Closing Time, the
     Registration Statement and any amendments thereto complied and will comply
     in all material respects with the requirements of the 1933 Act and the
     1933 Act Regulations and the 1939 Act and the rules and regulations of the
     Commission under the 1939 Act (the "1939 Act Regulations") and did not and
     will not contain an untrue statement of a material fact or omit to state a
     material fact required to be stated therein or necessary to make the
     statements therein not misleading. At the date of the Prospectus and at
     the Closing Time, neither the Prospectus nor any amendments and
     supplements thereto included or will include an untrue statement of a
     material fact or omitted or will omit to state a material fact necessary
     in order to make the statements therein, in the light of the circumstances
     under which they were made, not misleading. Notwithstanding the foregoing,
     the representations and warranties in this subsection shall not apply to
     statements in or omissions from the Registration Statement or the
     Prospectus made in reliance upon and in conformity with information
     furnished to the Company in writing by any Underwriter through any of the
     Representatives expressly for use in the Registration Statement or the
     Prospectus.

          Each preliminary prospectus and prospectus filed as part of the
     Registration Statement as originally filed or as part of any amendment
     thereto, or filed pursuant to Rule 424 under the 1933 Act, complied when
     so filed in all material respects with the 1933 Act Regulations and each
     preliminary prospectus and the Prospectus delivered to the Underwriters
     for use in connection with the offering of Underwritten Securities will,
     at the time of such delivery, be identical to any electronically
     transmitted copies thereof filed with the Commission pursuant to EDGAR,
     except to the extent permitted by Regulation S-T.

          (2) Incorporated Documents. The documents incorporated or deemed to
     be incorporated by reference in the Registration Statement and the
     Prospectus, when they became effective or at the time they were or
     hereafter are filed with the Commission, complied with and will comply in
     all material respects with the requirements of the 1934 Act and the rules
     and regulations of the Commission thereunder (the "1934 Act Regulations")


                                       3
<PAGE>   7

     and, when read together with the other information in the Prospectus, at
     the date of the Prospectus and at the Closing Time, did not and will not
     contain an untrue statement of a material fact or omit to state a material
     fact necessary in order to make the statements therein, in the light of the
     circumstances under which they were made, not misleading.

          (3) Independent Accountants. The accountants who certified the
     financial statements and any supporting schedules thereto included in the
     Registration Statement and the Prospectus are independent public
     accountants as required by the 1933 Act and the 1933 Act Regulations.

          (4) Financial Statements. The historical consolidated financial
     statements of the Company included in the Registration Statement and the
     Prospectus, together with the related schedules and notes, present fairly
     in all material respects the financial position of the Company and its
     consolidated subsidiaries at the dates indicated and the statements of
     operations, stockholders' equity and cash flows of the Company and its
     consolidated subsidiaries for the periods specified. Such financial
     statements have been prepared in conformity with generally accepted
     accounting principles ("GAAP") applied on a consistent basis throughout
     the periods involved. The schedules supporting the historical financial
     statements of the Company and its consolidated subsidiaries, if any,
     included in the Registration Statement and the Prospectus present fairly
     and in all material respects in accordance with GAAP the information
     required to be stated therein. The selected financial data and the summary
     financial information relating to the historical financial statements of
     the Company and its consolidated subsidiaries included in the Prospectus
     present fairly the information shown therein and have been compiled on a
     basis consistent with that of the audited financial statements included in
     the Registration Statement.

          (5) No Material Adverse Change in Business. Since the respective
     dates as of which information is given in the Registration Statement and
     the Prospectus, except as otherwise stated therein, (A) there has been no
     material adverse change in the financial condition, or in the earnings,
     business affairs or properties, or development involving a prospective
     material adverse change in the business affairs of the Company and its
     subsidiaries considered as one enterprise, whether or not arising in the
     ordinary course of business (a "Material Adverse Effect"), (B) there have
     been no transactions entered into by the Company or any of its
     subsidiaries, other than those arising in the ordinary course of business,
     which are material with respect to the Company and its subsidiaries
     considered as one enterprise and (C) except for regular dividends on the
     Company's common stock or preferred stock, in amounts per share that are
     consistent with past practice or the applicable charter document or
     supplement thereto, respectively, there has been no dividend or
     distribution of any kind declared, paid or made by the Company on any
     class of its capital stock.

          (6) Good Standing of the Company. The Company has been duly organized
     and is validly existing as a corporation in good standing under the laws
     of the State of Delaware 

                                       4
<PAGE>   8

     and has corporate power and authority to own, lease and operate its
     properties and to conduct its business as described in the Prospectus and
     to enter into and perform its obligations under, or as contemplated under,
     this Underwriting Agreement. The Company is duly qualified as a foreign
     corporation to transact business and is in good standing in each other
     jurisdiction in which such qualification is required, whether by reason of
     the ownership or leasing of property or the conduct of business, except
     where the failure to so qualify or be in good standing would not result in
     a Material Adverse Effect.

          (7) Good Standing of Subsidiaries. Each "significant subsidiary" of
     the Company (as such term is defined in Rule 1-02 of Regulation S-X
     promulgated under the 1933 Act) (each, a "Subsidiary" and, collectively,
     the "Subsidiaries"), if any, has been duly organized and is validly
     existing as a corporation in good standing under the laws of the
     jurisdiction of its incorporation, has corporate power and authority to
     own, lease and operate its properties and to conduct its business as
     described in the Prospectus and is duly qualified as a foreign corporation
     to transact business and is in good standing in each jurisdiction in which
     such qualification is required, whether by reason of the ownership or
     leasing of property or the conduct of business, except where the failure
     to so qualify or be in good standing would not result in a Material
     Adverse Effect. Except as otherwise stated in the Registration Statement
     and the Prospectus, all of the issued and outstanding capital stock of
     each Subsidiary has been duly authorized and is validly issued, fully paid
     and non-assessable and, except for directors' qualifying shares, is owned
     by the Company, directly or through subsidiaries, free and clear of any
     security interest, mortgage, pledge, lien, encumbrance, claim or equity.
     None of the outstanding shares of capital stock of any Subsidiary was
     issued in violation of preemptive or other similar rights of any security
     holder of such Subsidiary.

          (8) Capitalization. The authorized, issued and outstanding shares of
     capital stock of the Company are as set forth in the column entitled
     "Actual" under the "Capitalization" section of the Prospectus (except for
     subsequent issuances thereof, if any, pursuant to reservations, agreements
     or employee benefit plans referred to in the Prospectus or pursuant to the
     exercise of convertible securities or options referred to in the
     Prospectus). Such shares of capital stock have been duly authorized and
     validly issued by the Company and are fully paid and non-assessable, and
     none of such shares of capital stock was issued in violation of preemptive
     or other similar rights of any security holder of the Company.

          (9) Authorization of this Underwriting Agreement. This Underwriting
     Agreement has been, as of the date hereof, duly authorized, executed and
     delivered by the Company.

          (10) Authorization of the Underwritten Securities. The Underwritten
     Securities have been duly authorized by the Company for issuance and sale
     pursuant to this Underwriting Agreement. Such Underwritten Securities when
     issued and authenticated in the manner provided for in the applicable
     Indenture and delivered against payment of the consideration therefor
     specified in this Underwriting Agreement, will constitute valid and


                                       5
<PAGE>   9


     binding obligations of the Company, enforceable against the Company in
     accordance with their terms, except as the enforcement thereof may be
     limited by bankruptcy, insolvency (including, without limitation, all laws
     relating to fraudulent transfers), reorganization, moratorium or other
     similar laws affecting the enforcement of creditors' rights generally or by
     general equitable principles (regardless of whether enforcement is
     considered in a proceeding in equity or at law). Such Underwritten
     Securities will be in the form contemplated by, and each registered holder
     thereof is entitled to the benefits of, the Indenture.

          (11) Authorization of the Indenture. The Indenture has been duly
     authorized, executed and delivered by the Company and, upon such
     authorization, execution and delivery, will constitute a valid and binding
     agreement of the Company, enforceable against the Company in accordance
     with its terms, except as the enforcement thereof may be limited by
     bankruptcy, insolvency (including, without limitation, all laws relating
     to fraudulent transfers), reorganization, moratorium or other similar laws
     affecting the enforcement of creditors' rights generally or by general
     equitable principles (regardless of whether enforcement is considered in a
     proceeding in equity or at law).

          (12) Descriptions of the Underwritten Securities and Indenture. The
     Underwritten Securities and the Indenture conform in all material respects
     to the statements relating thereto contained in the Prospectus and will be
     in substantially the form filed or incorporated by reference, as the case
     may be, as an exhibit to the Registration Statement.

          (13) Absence of Defaults and Conflicts. Neither the Company nor any
     of its subsidiaries is in violation of its charter or by-laws or in
     default in the performance or observance of any obligation, agreement,
     covenant or condition contained in any contract, indenture, mortgage, deed
     of trust, loan or credit agreement, note, lease or other agreement or
     instrument to which the Company or any of its subsidiaries is a party or
     by which it or any of them may be bound, or to which any of the assets,
     properties or operations of the Company or any of its subsidiaries is
     subject (collectively, "Agreements and Instruments"), except for such
     violations or defaults that would not result in a Material Adverse Effect.
     The execution, delivery and performance of this Underwriting Agreement and
     the Indenture and the consummation of the transactions contemplated herein
     and in the Registration Statement and the Prospectus (including the
     issuance and sale of the Underwritten Securities and the use of the
     proceeds from the sale of the Underwritten Securities as described under
     the caption "Use of Proceeds") and compliance by the Company with its
     obligations hereunder and thereunder have been duly authorized by all
     necessary corporate action and do not and will not, whether with or
     without the giving of notice or passage of time or both, conflict with or
     constitute a breach of, or default or Repayment Event (as defined below)
     under, or result in the creation or imposition of any lien, charge or
     encumbrance upon any assets, properties or operations of the Company or
     any of its subsidiaries pursuant to, any Agreements and Instruments
     (except for such conflicts, breaches or defaults, or liens, charges or
     encumbrances that would not result in, or be reasonably expected to result
     in, a Material 

                                       6
<PAGE>   10


     Adverse Effect), nor will such action result in any violation of the
     provisions of the charter or by-laws of the Company or any of its
     Subsidiaries or any applicable law, statute, rule, regulation, judgment,
     order, writ or decree of any government, government instrumentality or
     court, domestic or foreign, having jurisdiction over the Company or any of
     its Subsidiaries or any of their assets, properties or operations. As used
     herein, a "Repayment Event" means any event or condition which gives the
     holder of any note, debenture or other evidence of indebtedness (or any
     person acting on such holder's behalf) the right to require the repurchase,
     redemption or repayment of all or a portion of such indebtedness by the
     Company or any of its subsidiaries.

          (14) Absence of Labor Dispute. No labor dispute with the employees of
     the Company or any of its subsidiaries exists or, to the knowledge of the
     Company, is imminent.

          (15) Absence of Proceedings. There is no action, suit, proceeding,
     inquiry or investigation before or brought by any court or governmental
     agency or body, domestic or foreign, now pending, or to the knowledge of
     the Company overtly threatened, against or affecting the Company or any of
     its subsidiaries which is required to be disclosed in the Registration
     Statement and the Prospectus (other than as stated therein), or which
     might reasonably be expected to result in a Material Adverse Effect, or
     which might reasonably be expected to materially and adversely affect the
     consummation of the transactions contemplated under the Prospectus, this
     Underwriting Agreement or the Indenture, or the performance by the Company
     of its obligations hereunder and thereunder. The aggregate of all pending
     legal or governmental proceedings to which the Company or any of its
     subsidiaries is a party or of which any of their respective assets,
     properties or operations is the subject which are not described in the
     Registration Statement and the Prospectus, including ordinary routine
     litigation incidental to the business, could not reasonably be expected to
     result in a Material Adverse Effect.

          (16) Accuracy of Exhibits. There are no contracts or documents which
     are required to be described in the Registration Statement, the Prospectus
     or the documents incorporated by reference therein or to be filed as
     exhibits thereto which have not been so described and filed as required.

          (17) Absence of Further Requirements. No filing with, or
     authorization, approval, consent, license, order, registration,
     qualification or decree of, any court or governmental authority or agency,
     domestic or foreign, is necessary or required for the due authorization,
     execution and delivery by the Company of this Underwriting Agreement or
     for the performance by the Company of the transactions contemplated under
     the Prospectus, this Underwriting Agreement or the Indenture, except such
     as have been already made, obtained or rendered, as applicable or as may
     be required under the 1933 Act, or the 1933 Act Regulations and foreign or
     state securities or blue sky laws.



                                       7
<PAGE>   11

          (18) Possession of Intellectual Property. The Company and its
     subsidiaries own or possess, or can acquire on reasonable terms, adequate
     patents, patent rights, licenses, inventions, copyrights, know-how
     (including trade secrets and other unpatented and/or unpatentable
     proprietary or confidential information, systems or procedures),
     trademarks, service marks, trade names or other intellectual property
     (collectively, "Intellectual Property") necessary to carry on the business
     now operated by them, and neither the Company nor any of its subsidiaries
     has received any notice or is otherwise aware of any infringement of or
     conflict with asserted rights of others with respect to any Intellectual
     Property or of any facts or circumstances which would render any
     Intellectual Property invalid or inadequate to protect the interest of the
     Company or any of its subsidiaries therein, and which infringement or
     conflict (if the subject of any unfavorable decision, ruling or finding) or
     invalidity or inadequacy, singly or in the aggregate, would result in a
     Material Adverse Effect.

          (19) Possession of Licenses and Permits. The Company and its
     subsidiaries possess such permits, licenses, approvals, consents and other
     authorizations (collectively, "Governmental Licenses") issued by the
     appropriate federal, state, local or foreign regulatory agencies or bodies
     necessary to conduct the business now operated by them except where the
     failure to have such Government Licenses would not result in, or be
     reasonably expected to result in, a Material Adverse Effect. The Company
     and its subsidiaries are in compliance with the terms and conditions of
     all such Governmental Licenses, except where the failure so to comply
     would not, singly or in the aggregate, result in a Material Adverse
     Effect. All of the Governmental Licenses are valid and in full force and
     effect, except where the invalidity of such Governmental Licenses or the
     failure of such Governmental Licenses to be in full force and effect would
     not result in a Material Adverse Effect. Neither the Company nor any of
     its subsidiaries has received any notice of proceedings relating to the
     revocation or modification of any such Governmental Licenses which, singly
     or in the aggregate, if the subject of an unfavorable decision, ruling or
     finding, would result in a Material Adverse Effect.

          (20) Title to Property. The Company and its subsidiaries have good
     and indefeasible title to all offshore drilling rigs described as being
     owned by them in the Prospectus. All of the leases and subleases material
     to the business of the Company and its subsidiaries considered as one
     enterprise, and under which the Company or any of its subsidiaries holds
     offshore drilling rigs described in the Prospectus, are in full force and
     effect, and neither the Company nor any of its subsidiaries has received
     any notice of any material claim of any sort that has been asserted by
     anyone adverse to the rights of the Company or any of its subsidiaries
     under any of the leases or subleases mentioned above, or affecting or
     questioning the rights of the Company or such subsidiary of the continued
     possession of the leased or subleased premises under any such lease or
     sublease.

          (21) Commodity Exchange Act. The Underwritten Securities upon
     issuance, will be excluded or exempted under, or beyond the purview of,
     the Commodity Exchange Act, 


                                       8
<PAGE>   12

     as amended (the "Commodity Exchange Act"), and the rules and regulations of
     the Commodity Futures Trading Commission under the Commodity Exchange Act
     the "Commodity Exchange Act Regulations").

          (22) Investment Company Act. The Company is not, and upon the
     issuance and sale of the Underwritten Securities as herein contemplated
     and the application of the net proceeds therefrom as described in the
     Prospectus will not be, an "investment company" within the meaning of the
     Investment Company Act of 1940, as amended (the "1940 Act").

          (23) Environmental Laws. Except as otherwise stated in the
     Registration Statement and the Prospectus and except as would not, singly
     or in the aggregate, result in a Material Adverse Effect, (A) neither the
     Company nor any of its subsidiaries is in violation of any federal, state,
     local or foreign statute, law, rule, regulation, ordinance, code, policy
     or rule of common law or any judicial or administrative interpretation
     thereof including any judicial or administrative order, consent, decree or
     judgment, relating to pollution or protection of human health, the
     environment (including, without limitation, ambient air, surface water,
     groundwater, land surface or subsurface strata) or wildlife, including,
     without limitation, laws and regulations relating to the release or
     threatened release of chemicals, pollutants, contaminants, wastes, toxic
     substances, hazardous substances, petroleum or petroleum products
     (collectively, "Hazardous Materials") or to the manufacture, processing,
     distribution, use, treatment, storage, disposal, transport or handling of
     Hazardous Materials (collectively, "Environmental Laws"), (B) the Company
     and each of its Subsidiaries have all permits, authorizations and
     approvals required under any applicable Environmental Laws and are in
     compliance with their requirements, (C) there are no pending or threatened
     administrative, regulatory or judicial actions, suits, demands, demand
     letters, claims, liens, notices of noncompliance or violation,
     investigation or proceedings relating to any Environmental Law against the
     Company or any of its subsidiaries and (D) there are no events or
     circumstances that might reasonably be expected to form the basis of an
     order for clean-up or remediation, or an action, suit or proceeding by any
     private party or governmental body or agency, against or affecting the
     Company or any of its subsidiaries relating to Hazardous Materials or any
     Environmental Laws.

     (b) Officers Certificates. Any certificate signed by any officer of the
Company or any of its subsidiaries and delivered to any Underwriter or to
counsel for the Underwriters in connection with the offering of the
Underwritten Securities shall be deemed a representation and warranty by the
Company to each Underwriter as to the matters covered thereby on the date of
such certificate and, unless subsequently amended or supplemented, at the
Closing Time.

     SECTION 2. Sale and Delivery to Underwriters; Closing.

     (a) Underwritten Securities. The several commitments of the Underwriters
to purchase the Underwritten Securities pursuant to this Underwriting Agreement
shall be deemed to have been made on the basis of the representations,
warranties and agreements herein contained and shall be 

                                       9
<PAGE>   13

subject to the terms and conditions herein set forth. The Company agrees to sell
to each Underwriter, severally and not jointly, and each Underwriter, severally
and not jointly, agrees to purchase from the Company, at the price set forth in
Schedule B-1 and Schedule B-2, the aggregate principal amount of respective
Underwritten Securities set forth in Schedule A-1 and Schedule A-2 opposite the
name of such Underwriter, plus any additional principal amount of Underwritten
Securities which such Underwriter may become obligated to purchase pursuant to
the provisions of Section 10 hereof.

     (b) Payment. Payment of the purchase price for, and delivery of, the
Underwritten Securities shall be made at the offices of Andrews & Kurth L.L.P.,
600 Travis, Suite 4200, Houston, Texas 77002, or at such other place as shall
be agreed upon by the Representatives and the Company, at 9:00 A.M. (Central
time) on the third (fourth, if the pricing occurs after 3:30 P.M. (Central
time) on any given day) business day after the date hereof (unless postponed in
accordance with the provisions of Section 10 hereof), or such other time not
later than ten business days after such date as shall be agreed upon by the
Representatives and the Company (such time and date of payment and delivery
being herein called "Closing Time").

     Payment shall be made to the Company by wire transfer of immediately
available funds to a bank account designated by the Company, against delivery
to the Representatives for the respective accounts of the Underwriters of one
or more Global Notes (as defined in the Indenture) in the aggregate principal
amount of the 2009 Notes and one or more Global Notes in the aggregate
principal amount of the 2019 Notes to be purchased by the Underwriters. It is
understood that each Underwriter has authorized the Representatives for their
account, to accept delivery of, receipt for, and make payment of the purchase
price for, the Underwritten Securities which it has severally agreed to
purchase. The Representatives, individually and not as representatives of the
Underwriters, may (but shall not be obligated to) make payment of the purchase
price for the Underwritten Securities to be purchased by any Underwriter whose
funds have not been received by the Closing Time, but such payment shall not
relieve such Underwriter from its obligations hereunder.

     (c) Denominations; Registration. The Global Notes evidencing the
Underwritten Securities shall be registered in such names as the
Representatives may request in writing at least one full business day prior to
the Closing Time. The Global Notes evidencing the Underwritten Securities will
be made available for examination and packaging by the Representatives in The
City of New York not later than 3:00 P.M. (Eastern time) on the business day
prior to the Closing Time.

     SECTION 3. Covenants of the Company. The Company covenants with each
Underwriter participating in the offering of Underwritten Securities, as
follows:

     (a) Compliance with Securities Regulations and Commission Requests. The
Company, subject to Section 3(b), will comply with the requirements of Rule
430A of the 1933 Act Regulations and will notify the Representatives
immediately, and confirm the notice in writing, of (i) the effectiveness of any
post-effective amendment to the Registration Statement or the filing of any
supplement or amendment to the Prospectus, (ii) the receipt of any comments
from the Commission, 


                                      10
<PAGE>   14


(iii) any request by the Commission for any amendment to the Registration
Statement or any amendment or supplement to the Prospectus or for additional
information, and (iv) the issuance by the Commission of any stop order
suspending the effectiveness of the Registration Statement or of any order
preventing or suspending the use of any preliminary prospectus, or of the
suspension of the qualification of the Underwritten Securities for offering or
sale in any jurisdiction, or of the initiation or threatening of any proceedings
for any of such purposes. The Company will promptly effect the filings necessary
pursuant to Rule 424 and will take such steps as it deems necessary to ascertain
promptly whether the Prospectus transmitted for filing under Rule 424 was
received for filing by the Commission and, in the event that it was not, it will
promptly file the Prospectus. The Company will make every reasonable effort to
prevent the issuance of any stop order and, if any stop order is issued, to
obtain the lifting thereof at the earliest possible moment.

     (b) Filing of Amendments. The Company will give the Representatives notice
of its intention to file or prepare any amendment to the Registration Statement
or any amendment, supplement or revision to either the prospectus included in
the Registration Statement at the time it became effective or to the
Prospectus, whether pursuant to the 1933 Act, the 1934 Act or otherwise, will
furnish the Representatives with copies of any such documents a reasonable
amount of time prior to such proposed filing or use, as the case may be, and
will not file or use any such document to which the Representatives or counsel
for the Underwriters shall reasonably object.

     (c) Delivery of Registration Statements. The Company has furnished or will
deliver to the Representatives and counsel for the Underwriters, without
charge, signed copies of the Registration Statement as originally filed and of
each amendment thereto (including exhibits filed therewith or incorporated by
reference therein and documents incorporated or deemed to be incorporated by
reference therein) and signed copies of all consents and certificates of
experts, and will also deliver to the Representatives, without charge, a
conformed copy of the Registration Statement as originally filed and of each
amendment thereto (without exhibits) for each of the Underwriters. The
Registration Statement and each amendment thereto furnished to the Underwriters
will be identical to any electronically transmitted copies thereof filed with
the Commission pursuant to EDGAR, except to the extent permitted by Regulation
S-T.

     (d) Delivery of Prospectuses. The Company will deliver to each
Underwriter, without charge, as many copies of each preliminary prospectus as
such Underwriter may reasonably request, and the Company hereby consents to the
use of such copies for purposes permitted by the 1933 Act. The Company will
furnish to each Underwriter, without charge, during the period when the
Prospectus is required to be delivered under the 1933 Act or the 1934 Act, such
number of copies of the Prospectus as such Underwriter may reasonably request.
The Prospectus and any amendments or supplements thereto furnished to the
Underwriters will be identical to any electronically transmitted copies thereof
filed with the Commission pursuant to EDGAR, except to the extent permitted by
Regulation S-T.

     (e) Continued Compliance with Securities Laws. The Company will comply
with the 1933 Act and the 1933 Act Regulations and the 1934 Act and the 1934
Act Regulations so as to 

                                      11
<PAGE>   15


permit the completion of the distribution of the Underwritten Securities as
contemplated in this Underwriting Agreement and in the Registration Statement
and the Prospectus. If at any time when the Prospectus is required by the 1933
Act or the 1934 Act to be delivered in connection with sales of the Underwritten
Securities, any event shall occur or condition shall exist as a result of which
it is necessary, in the opinion of counsel for the Underwriters or for the
Company, to amend the Registration Statement in order that the Registration
Statement will not contain an untrue statement of a material fact or omit to
state a material fact required to be stated therein or necessary to make the
statements therein not misleading or to amend or supplement the Prospectus in
order that the Prospectus will not include an untrue statement of a material
fact or omit to state a material fact necessary in order to make the statements
therein not misleading in the light of the circumstances existing at the time it
is delivered to a purchaser, or if it shall be necessary, in the opinion of such
counsel, at any such time to amend the Registration Statement or amend or
supplement the Prospectus in order to comply with the requirements of the 1933
Act or the 1933 Act Regulations, the Company will promptly prepare and file with
the Commission, subject to Section 3(b), such amendment or supplement as may be
necessary to correct such statement or omission or to make the Registration
Statement or the Prospectus comply with such requirements, and the Company will
furnish to the Underwriters, without charge, such number of copies of such
amendment or supplement as the Underwriters may reasonably request.

     (f) Blue Sky Qualifications. The Company will use its best efforts, in
cooperation with the Underwriters, to qualify the Underwritten Securities for
offering and sale under the applicable securities laws of such states and other
jurisdictions (domestic or foreign) as the Representatives may designate and to
maintain such qualifications in effect for a period of not less than one year
from the date of this Underwriting Agreement; provided, however, that the
Company shall not be obligated to file any general consent to service of
process or to qualify as a foreign corporation or as a dealer in securities in
any jurisdiction in which it is not so qualified or to subject itself to
taxation in respect of doing business in any jurisdiction in which it is not
otherwise so subject. In each jurisdiction in which the Underwritten Securities
have been so qualified, the Company will file such statements and reports as
may be required by the laws of such jurisdiction to continue such qualification
in effect for a period of not less than one year from the date of this
Underwriting Agreement.

     (g) Earnings Statement. The Company will timely file such reports pursuant
to the 1934 Act as are necessary in order to make generally available to its
securityholders as soon as practicable an earnings statement for the purposes
of, and to provide the benefits contemplated by, the last paragraph of Section
11(a) of the 1933 Act.

     (h) Tender Offer and Consent Solicitation. The Company will use its best
efforts to complete the tender offer for the Company's outstanding $125 million
principal amount of 9 1/8% Senior Notes due 2006 and the related consent
solicitation by the expiration date set forth in the Company's Offer to
Purchase and Consent Solicitation Statement, dated February 19, 1999.



                                      12
<PAGE>   16


     (i) Use of Proceeds. The Company will use the net proceeds received by it
from the sale of the Underwritten Securities in the manner specified in the
Prospectus under "Use of Proceeds."

     (j) Restriction on Sale of Securities. Between the date of this
Underwriting Agreement and the Closing Time the Company will not, without the
prior written consent of the Representatives, directly or indirectly, issue,
sell, offer or contract to sell, grant any option for the sale of, or otherwise
dispose of, any debt securities of the Company (excluding bank indebtedness).

     (k) Reporting Requirements. The Company, during the period when the
Prospectus is required to be delivered under the 1933 Act or the 1934 Act, will
file all documents required to be filed with the Commission pursuant to the
1934 Act within the time periods required by the 1934 Act and the 1934 Act
Regulations.

     SECTION 4. Payment of Expenses.

     (a) Expenses. The Company will pay all expenses incident to the
performance of its obligations under this Underwriting Agreement, including (i)
the preparation, printing and filing of the Registration Statement (including
financial statements and exhibits) as originally filed and of each amendment
thereto, (ii) the preparation, printing and delivery to the Underwriters of
this Underwriting Agreement, any Agreement among Underwriters, the Indenture
and such other documents as may be required in connection with the offering,
purchase, sale, issuance or delivery of the Underwritten Securities, (iii) the
preparation, issuance and delivery of the Underwritten Securities, any
certificates for the Underwritten Securities to the Underwriters, including any
transfer taxes and any stamp or other duties payable upon the sale, issuance or
delivery of the Underwritten Securities to the Underwriters, (iv) the fees and
disbursements of the Company's counsel, accountants and other advisors or
agents (including transfer agents and registrars), as well as the fees and
disbursements of the Trustee and its counsel, (v) the qualification of the
Underwritten Securities under state securities laws in accordance with the
provisions of Section 3(f) hereof, including filing fees and the reasonable
fees and disbursements of counsel for the Underwriters in connection therewith
and in connection with the preparation of any Blue Sky Survey, and any
amendment thereto, (vi) the printing and delivery to the Underwriters of copies
of each preliminary prospectus, and the Prospectus and any amendments or
supplements thereto, (vii) the fees charged by nationally recognized
statistical rating organizations for the rating of the Underwritten Securities
and (viii) the filing fees incident to, and the reasonable fees and
disbursements of counsel to the Underwriters in connection with, the review, if
any, by the National Association of Securities Dealers, Inc. (the "NASD") of
the terms of the sale of the Underwritten Securities.

     (b) Termination of Agreement. If this Underwriting Agreement is terminated
by the Representatives in accordance with the provisions of Section 5 or
Section 9(a)(i) hereof, the Company shall reimburse the Underwriters for all of
their out-of-pocket expenses, including the reasonable fees and disbursements
of counsel for the Underwriters.



                                      13
<PAGE>   17

     SECTION 5. Conditions of Underwriters Obligations. The obligations of the
Underwriters to purchase and pay for the Underwritten Securities pursuant this
Underwriting Agreement are subject to the accuracy of the representations and
warranties of the Company contained in Section 1 hereof or in certificates of
any officer of the Company delivered pursuant to the provisions hereof, to the
performance by the Company of its covenants and other obligations hereunder,
and to the following further conditions:

     (a) Effectiveness of Registration Statement. The Registration Statement
has become effective under the 1933 Act and no stop order suspending the
effectiveness of the Registration Statement shall have been issued under the
1933 Act and no proceedings for that purpose shall have been instituted or be
pending or threatened by the Commission, and any request on the part of the
Commission for additional information shall have been complied with to the
reasonable satisfaction of counsel to the Underwriters. A prospectus containing
information relating to the description of the Underwritten Securities, the
specific method of distribution and similar matters shall have been filed with
the Commission in accordance with Rule 424(b)(1), (2), (3), (4) or (5), as
applicable (or any required post-effective amendment providing such information
shall have been filed and declared effective in accordance with the
requirements of Rule 430A), or, if the Company has elected to rely upon Rule
434 of the 1933 Act Regulations, a Term Sheet including the Rule 434
Information shall have been filed with the Commission in accordance with Rule
424(b)(7).

     (b) Opinion of Counsel for Company. At Closing Time, the Representatives
shall have received the favorable opinion, dated as of the Closing Time, of
Thompson & Knight, P.C., counsel for the Company, in form and substance
reasonably satisfactory to counsel for the Underwriters, together with signed
or reproduced copies of such letter for each of the other Underwriters, to the
effect set forth in Exhibit A hereto and to such further effect as counsel to
the Underwriters may reasonably request.

     (c) Opinion of Counsel for Underwriters. At Closing Time, the
Representatives shall have received the favorable opinion, dated as of the
Closing Time, of Andrews & Kurth L.L.P., counsel for the Underwriters, together
with signed or reproduced copies of such letter for each of the other
Underwriters, with respect to the matters set forth in (1), (2), (6), (7) (it
being understood that any opinion required with respect to the Underwritten
Securities, not being subject to preemptive or other similar rights of the
securityholders of the Company shall be limited to such rights arising by
operation of law or under the charter or by-laws of the Company), (9), (10)
(solely as to the information in the Prospectus under any caption purporting to
describe any such Securities), (16), (17), (20) and the penultimate paragraph
of Exhibit A hereto. In giving such opinion, such counsel may rely, as to all
matters governed by the laws of jurisdictions other than the law of the State
of New York, the federal law of the United States and the General Corporation
Law of the State of Delaware, upon the opinions of counsel satisfactory to the
Representatives. Such counsel may also state that, insofar as such opinion
involves factual matters, they have relied, to the extent they deem proper,
upon certificates of officers of the company and its subsidiaries and
certificates of public officials.



                                      14
<PAGE>   18


     (d) Officers, Certificate. At Closing Time, there shall not have been,
since the date of this Underwriting Agreement or since the respective dates as
of which information is given in the Prospectus, any material adverse change in
the financial condition, or in the earnings, business affairs or properties, or
development involving a prospective material adverse change in the business
affairs of the Company and its subsidiaries considered as one enterprise,
whether or not arising in the ordinary course of business, and the
Representatives shall have received a certificate of the Chief Executive
Officer, President or a Vice President of the Company and of the chief financial
officer or chief accounting officer of the Company, dated as of Closing Time, to
the effect that (i) there has been no such material adverse change, (ii) the
representations and warranties in Section 1(a) are true and correct with the
same force and effect as though expressly made at and as of the Closing Time,
(iii) the Company has complied with all agreements and satisfied all conditions
on its part required under this Underwriting Agreement to be performed or
satisfied at or prior to the Closing Time, and (iv) no stop order suspending the
effectiveness of the Registration Statement has been issued and no proceedings
for that purpose have been instituted, are pending or, to the best of such
officer's knowledge, are threatened by the Commission.

     (e) Accountants Comfort Letter. At the time of the execution of this
Underwriting Agreement, the Representatives shall have received from
PricewaterhouseCoopers LLP a letter dated such date, in form and substance
reasonably satisfactory to the Representatives, together with signed or
reproduced copies of such letter for each of the other Underwriters, containing
statements and information of the type ordinarily included in accountants'
"comfort letters" to underwriters with respect to the financial statements and
certain financial information contained in the Registration Statement and the
Prospectus.

     (f) Bring-down Comfort Letter. At Closing Time, the Representatives shall
have received from PricewaterhouseCoopers LLP a letter, dated as of Closing
Time, to the effect that they reaffirm the statements made in the letter
furnished pursuant to subsection (e) of this Section 5, except that the
specified date referred to shall be a date not more than three business days
prior to the Closing Time.

     (g) Ratings. At Closing Time, the Underwritten Securities shall have the
ratings of at least Baa2 by Moody's Investor's Service Inc. and A- by Standard
& Poor's Ratings Group, a division of McGraw-Hill Inc., and the Company shall
have delivered to the Representatives a letter, dated as of such date, from
each such rating organization, or other evidence satisfactory to the
Representatives, confirming that the Underwritten Securities have such ratings.
Since the time of execution of this Underwriting Agreement, there shall not
have occurred a downgrading in, or withdrawal of, the rating assigned to the
Underwritten Securities or any of the Company's other debt securities by a
"nationally recognized statistical rating agency", as that term is defined by
the Commission for purposes of Rule 436(g)(2) under the 1933 Act Regulations,
and no such rating organization shall have publicly announced that it has under
surveillance or review its rating of the Underwritten Securities or any of the
Company's other debt.


                                      15
<PAGE>   19



     (h) No Objection. If the Registration Statement or an offering of
Underwritten Securities has been filed with the NASD for review, the NASD shall
not have raised any objection with respect to the fairness and reasonableness
of the underwriting terms and arrangements.

     (i) Additional Documents. At Closing Time, counsel for the Underwriters
shall have been furnished with such documents and opinions as they may require
for the purpose of enabling them to pass upon the issuance and sale of the
Underwritten Securities as herein contemplated, or in order to evidence the
accuracy of any of the representations or warranties, or the fulfillment of any
of the conditions, herein contained; and all proceedings taken by the Company
in connection with the issuance and sale of the Underwritten Securities as
herein contemplated shall be satisfactory in form and substance to the
Representatives and counsel for the Underwriters.

     (j) Termination of this Underwriting Agreement. If any condition specified
in this Section 5 shall not have been fulfilled when and as required to be
fulfilled, this Underwriting Agreement may be terminated by the Representatives
by notice to the Company at any time at or prior to the Closing Time, and such
termination shall be without liability of any party to any other party except
as provided in Section 4 and except that Sections 1, 6, 7 and 8 shall survive
any such termination and remain in full force and effect.

     SECTION 6. Indemnification.

     (a) Indemnification of Underwriters. The Company agrees to indemnify and
hold harmless each Underwriter and each person, if any, who controls any
Underwriter within the meaning of Section 15 of the 1933 Act or Section 20 of
the 1934 Act as follows:

          (1) against any and all loss, liability, claim, damage and expense
     whatsoever, as incurred, arising out of any untrue statement or alleged
     untrue statement of a material fact contained in the Registration
     Statement (or any amendment thereto), including the Rule 430A Information
     deemed to be a part thereof, if applicable, or the omission or alleged
     omission therefrom of a material fact required to be stated therein or
     necessary to make the statements therein not misleading or arising out of
     any untrue statement or alleged untrue statement of a material fact
     included in any preliminary prospectus or the Prospectus (or any amendment
     or supplement thereto), or the omission or alleged omission therefrom of a
     material fact necessary in order to make the statements therein, in the
     light of the circumstances under which they were made, not misleading:

          (2) against any and all loss, liability, claim, damage and expense
     whatsoever, as incurred, to the extent of the aggregate amount paid in
     settlement of any litigation, or any investigation or proceeding by any
     governmental agency or body, commenced or threatened, or of any claim
     whatsoever based upon any such untrue statement or omission, or any such
     alleged untrue statement or omission; provided that (subject to Section
     6(d) below) any such settlement is effected with the written consent of
     the Company; and



                                      16
<PAGE>   20

          (3) against any and all expense whatsoever, as incurred (including
     the fees and disbursements of counsel chosen by the Representatives),
     reasonably incurred in investigation, preparing or defending against any
     litigation, or any investigation or proceeding by any governmental agency
     or body, commenced or threatened, or any claim whatsoever based upon any
     such untrue statement or omission, or any such alleged untrue statement or
     omission, to the extent that (x) the Company is required to do so under
     Section 6(d) below and (y) by any such expense is not paid under (1) or
     (2) above;

provided, however, that this indemnity agreement shall not apply to any loss,
liability, claim, damage or expense to the extent arising out of any untrue
statement or omission or alleged untrue statement or omission made in reliance
upon and in conformity with written information furnished to the Company by any
Underwriter through the Representatives expressly for use in the Registration
Statement (or any amendment thereto), including the Rule 430A Information
deemed to be a part thereof, if applicable, or any preliminary prospectus or
the Prospectus (or any amendment or supplement thereto); and provided, further,
that the foregoing indemnity with respect to any untrue statement contained in
or any omission from the preliminary prospectus shall not inure to the benefit
of any Underwriter (or any person controlling such Underwriter) from whom the
person asserting any such loss, liability, claim, damage or expense purchased
any of the Underwritten Securities that are the subject thereof if the Company
shall sustain the burden of proving that (i) the untrue statement or omission
contained in the preliminary prospectus was corrected; (ii) such person was not
sent or given a copy of the Prospectus (excluding documents incorporated by
reference) which corrected the untrue statement or omission at or prior to the
written confirmation of the sale of such Underwritten Securities to such person
if required by applicable law; and (iii) the Company satisfied its obligation
pursuant to Section 3(d) of this Agreement to provide a sufficient number of
copies of the Prospectus to the Underwriters.

     (b) Indemnification of Company, Directors and Officers. Each Underwriter
severally agrees to indemnify and hold harmless the Company, its directors,
each of its officers who signed the Registration Statement, and each person, if
any, who controls the Company within the meaning of Section 15 of the 1933 Act
or Section 20 of the 1934 Act against any and all loss, liability, claim,
damage and expense described in the indemnity contained in subsection (a) of
this Section, as incurred, but only with respect to untrue statements or
omission, or alleged untrue statements or omissions, made in the Registration
Statement (or any amendment thereto), including the Rule 430A Information
deemed to be a part thereof, if applicable, or any preliminary prospectus or
the Prospectus (or any amendment or supplement thereto) in reliance upon and in
conformity with written information furnished to the Company by such
Underwriter through the Representatives expressly for use in the Registration
Statement (or any amendment thereto) or such preliminary prospectus or the
Prospectus (or any amendment or supplement thereto).

     (c) Actions against Parties; Notification. Each indemnified party shall
give notice as promptly as reasonably practicable to each indemnifying party of
any action commenced against it in respect of which indemnity may be sought
hereunder, but failure to so notify an indemnifying party shall not relieve
such indemnifying party from any liability hereunder to the extent it is not


                                      17
<PAGE>   21


materially prejudiced as a result thereof and in any event shall not relieve it
from any liability which it may have otherwise than on account of this
indemnity agreement. In the case of parties indemnified pursuant to Section
6(a) above, counsel to the indemnified parties shall be selected by the
Representatives, and, in the case of parties indemnified pursuant to Section
6(b) above, counsel to the indemnified parties shall be selected by the Company.
The indemnifying party shall be entitled to appoint counsel of the indemnifying
party's choice at the indemnifying party's expense to represent the indemnified
party in any action for which indemnification is sought (in which case the
indemnifying party shall not thereafter be responsible for the fees and expenses
of any separate counsel retained by the indemnified party or parties except as
set forth below); provided, however, that such counsel shall be reasonably
satisfactory to the indemnified party. Notwithstanding the indemnifying party's
election to appoint counsel to represent the indemnified party in an action, the
indemnified party shall have the right to employ separate counsel (including
local counsel), and the indemnifying party shall bear the reasonable fees, costs
and expenses of such separate counsel if (i) the use of counsel chosen by the
indemnifying party to represent the indemnified party would present such counsel
with a conflict of interest, (ii) the actual or potential defendants in, or
targets of, any such action include both the indemnified party and the
indemnifying party and the indemnified party shall have reasonably concluded
that there may be legal defenses available to it and/or other indemnified
parties which are different from or additional to those available to the
indemnifying party, (iii) the indemnifying party shall not have employed counsel
reasonably satisfactory to the indemnified party to represent the indemnified
party within a reasonable time after notice of the institution of such action or
(iv) the indemnifying party shall authorize the indemnified party to employ
separate counsel at the expense of the indemnifying party. In no event shall the
indemnifying parties be liable for fees and expenses of more than one counsel
(in addition to any local counsel) separate from their own counsel for all
indemnified parties in connection with any action or separate but similar or
related actions in the same jurisdiction arising out of the same general
allegations or circumstances. In the case of any such separate firm for the
Underwriters and such control persons of the Underwriters, such firm shall be
designated in writing by the Representatives. In the case of any such separate
firm for the Company and such directors, officers and controlling persons of the
Company, such firm shall be designated in writing by the Company. No
indemnifying party shall, without the prior written consent of the indemnified
parties, settle or compromise or consent to the entry of any judgment with
respect to any litigation, or any investigation or proceeding by any
governmental agency or body, commenced or threatened, or any claim whatsoever in
respect of which indemnification or contribution could be sought under this
Section 6 or Section 7 hereof (whether or not the indemnified parties are actual
or potential parties thereto), unless such settlement compromise or consent (i)
includes an unconditional release of each indemnified party from all liability
arising out of such litigation, investigation, proceeding or claim and (ii) does
not include a statement as to or an admission of fault, culpability or a failure
to act by or on behalf of any indemnified party.

     (d) Settlement without Consent if Failure to Reimburse. If at any time an
indemnified party shall have requested an indemnifying party to reimburse the
indemnified party for fees and expenses of counsel for which such indemnifying
party is otherwise entitled to reimbursement pursuant to the terms of this
Agreement, such indemnifying party agrees that it shall be liable for any


                                      18
<PAGE>   22

settlement of the nature contemplated by Section 6(a)(ii) effected without its
written consent if (i) such settlement is entered into more than 60 days after
receipt by such indemnifying party of the aforesaid request, (ii) such
indemnifying party shall have received notice of the terms of such settlement
at least 30 days prior to such settlement being entered into and (iii) such
indemnifying party shall not have reimbursed such indemnified party in
accordance with such request prior to the date of such settlement.

     SECTION 7. Contribution. If the indemnification provided for in Section 6
hereof is for any reason unavailable to or insufficient to hold harmless an
indemnified party in respect of any losses, labilities, claims, damages or
expenses referred to therein, then each indemnifying party shall contribute to
the aggregate amount of such losses, liabilities, claims, damages and expenses
incurred by such indemnified party, as incurred, (i) in such proportion as is
appropriate to reflect the relative benefits received by the Company, on the
one hand, and the Underwriters, on the other hand, from the offering of the
Underwritten Securities pursuant to this Underwriting Agreement or (ii) if the
allocation provided by clause (i) is not permitted by applicable law, in such
proportion as is appropriate to reflect not only the relative benefits referred
to in clause (i) above but also the relative fault of the Company, on the one
hand, and of the Underwriters, on the other hand, in connection with the
statements or omissions which resulted in such losses, liabilities, claims,
damages or expenses, as well as any other relevant equitable considerations.

     The relative benefits received by the Company, on the one hand, and the
Underwriters, on the other hand, in connection with the offering of the
Underwritten Securities pursuant to this Underwriting Agreement shall be deemed
to be in the same respective proportions as the total net proceeds from the
offering of such Underwritten Securities (before deducting expenses) received
by the Company and the total underwriting discount received by the
Underwriters, in each case as set forth on the cover of the Prospectus, bear to
the aggregate initial public offering price of such Underwritten Securities as
set forth on such cover.

     The relative fault of the Company, on the one hand, and the Underwriters,
on the other hand, shall be determined by reference to, among other things,
whether any such untrue or alleged untrue statement of a material fact or
omission or alleged omission to state a material fact relates to information
supplied by the Company or by the Underwriters and the parties' relative
intent, knowledge, access to information and opportunity to correct or prevent
such statement or omission.

     The Company and the Underwriters agree that it would not be just and
equitable if contribution pursuant to this Section 7 were determined by pro
rata allocation (even if the Underwriters were treated as one entity for such
purpose) or by any other method of allocation which does not take account of
the equitable considerations referred to above in this Section 7. The aggregate
amount of losses, liabilities, claims, damages and expenses incurred by an
indemnified party and referred to above in this Section 7 shall be deemed to
include any legal or other expenses reasonably incurred by such indemnified
party in investigating, preparing or defending against any litigation, or any
investigation or proceeding by any governmental agency or body, commenced or


                                      19
<PAGE>   23

threatened, or any claim whatsoever based upon any such untrue or alleged untrue
statement or omission or alleged omission.

     Notwithstanding the provisions of this Section 7, no Underwriter shall be
required to contribute any amount in excess of the amount by which the total
price at which the Underwritten Securities underwritten by it and distributed
to the public were offered to the public exceeds the amount of any damages
which such Underwriter has otherwise been required to pay by reason of any such
untrue or alleged untrue statement or omission or alleged omission.

     No person guilty of fraudulent misrepresentation (within the meaning of
Section 11(f) of the 1933 Act) shall be entitled to contribution from any
person who was not guilty of such fraudulent misrepresentation.

     For purposes of this Section 7, each person, if any, who controls an
Underwriter within the meaning of Section 15 of the 1933 Act or Section 20 of
the 1934 Act shall have the same rights to contribution as such Underwriter,
and each director of the Company, each officer of the Company who signed the
Registration Statement, and each person, if any, who controls the Company
within the meaning of Section 15 of the 1933 Act or Section 20 of the 1934 Act
shall have the same rights to contribution as the Company. The Underwriters'
respective obligations to contribute pursuant to this Section 7 are several in
proportion to the aggregate principal amount of Underwritten Securities set
forth opposite their respective names in Schedule A-1 and A-2 hereto, and not
joint.

     SECTION 8. Representations, Warranties and Agreements to Survive Delivery.
All representations, warranties and agreements contained in this Underwriting
Agreement or in certificates of officers of the Company submitted pursuant
hereto shall remain operative and in full force and effect, regardless of any
investigation made by or on behalf of any Underwriter or controlling person, or
by or on behalf of the Company, and shall survive delivery of and payment for
the Underwritten Securities.

     SECTION 9. Termination.

     (a) Underwriting Agreement. The Representatives may terminate this
Underwriting Agreement, by notice to the Company, at any time at or prior to
the Closing Time, if (i) there has been, since the time of execution of this
Underwriting Agreement or since the respective dates as of which information is
given in the Prospectus, any material adverse change in the condition,
financial or otherwise, or in the earnings, business affairs or business
prospects of the Company and its subsidiaries considered as one enterprise,
whether or not arising in the ordinary course of business, or (ii) there has
occurred any material adverse change in the financial markets in the United
States , or any outbreak of hostilities or escalation thereof or other calamity
or crisis or any change or development involving a prospective change in
national or international political, financial or economic conditions, in each
case the effect of which is such as to make it, in the judgment of the
Representatives, impracticable to market the Underwritten Securities or to
enforce contracts for the sale of the Underwritten Securities, or (iii) trading
in any securities of the Company has been 

                                      20
<PAGE>   24

suspended or materially limited by the Commission or by the New York Stock
Exchange, or if trading generally on the New York Stock Exchange or the American
Stock Exchange or in the Nasdaq National Market has been suspended or materially
limited, or minimum or maximum prices for trading have been fixed, or maximum
ranges for prices have been required, by either of said exchanges or by such
system or by order of the Commission, the NASD or any other governmental
authority, or (iv) a banking moratorium has been declared by either Federal or
New York authorities.

     (b) Liabilities. If this Underwriting Agreement is terminated pursuant to
this Section 9, such termination shall be without liability of any party to any
other party except as provided in 
Section 4 hereof, and provided further that Sections 1, 6, 7 and 8 shall
survive such termination and remain in full force and effect.

     SECTION 10. Default by One or More of the Underwriters. If one or more of
the Underwriters shall fail at the Closing Time to purchase the Underwritten
Securities which it or they are obligated to purchase (the "Defaulted
Securities"), then the Representatives shall have the right, within 24 hours
thereafter, to make arrangements for one or more of the non-defaulting
Underwriters, or any other underwriters, to purchase all, but not less than
all, of the Defaulted Securities in such amounts as may be agreed upon and upon
the terms herein set forth; if, however, the Representatives shall not have
completed such arrangements within such 24-hour period, then:

          (a) if the aggregate principal amount of Defaulted Securities does
     not exceed 10% of the aggregate principal amount of Underwritten
     Securities to be purchased on such date, each of the non-defaulting
     Underwriters shall be obligated, severally and not jointly, to purchase
     the full amount thereof in the proportions that their respective
     underwriting obligations under Schedule A-1 and A-2 bear to the
     underwriting obligations of all non-defaulting Underwriters, or

          (b) if the aggregate principal amount of Defaulted Securities exceeds
     10% of the aggregate principal amount of Underwritten Securities to be
     purchased on such date this Underwriting Agreement shall terminate without
     liability on the part of any non-defaulting Underwriter.

     No action taken pursuant to this Section 10 shall relieve any defaulting
Underwriter from liability in respect of its default.

     In the event of any such default which does not result in a termination of
this Underwriting Agreement, either the Representatives or the Company shall
have the right to postpone the Closing Time for a period not exceeding seven
days in order to effect any required changes in the Registration Statement or
the Prospectus or in any other documents or arrangements.

     SECTION 11. Notices. All notices and other communications hereunder shall
be in writing and shall be deemed to have been duly given if mailed or
transmitted by any standard form of telecommunication. Notices to the
Underwriters shall be directed to Merrill Lynch at World


                                      21
<PAGE>   25

Financial Center, North Tower, New York, New York 10281-1201, attention of Bill
Montgomery; and notices to the Company shall be directed to it at 10370 Richmond
Avenue, Suite 400, Houston, Texas 77042, attention of Robert D. Campbell,
President.

     SECTION 12. Parties. This Underwriting Agreement shall inure to the
benefit of and be binding upon the Company, the Representatives and, upon
execution of this Underwriting Agreement, any other Underwriters and their
respective successors. Nothing expressed or mentioned in this Underwriting
Agreement is intended or shall be construed to give any person, firm or
corporation, other than the Underwriters and the Company and their respective
successors and the controlling persons and officers and directors referred to in
Sections 6 and 7 and their heirs and legal representatives, any legal or
equitable right, remedy or claim under or in respect of this Underwriting
Agreement or any provision herein contained. This Underwriting Agreement and all
conditions and provisions hereof are intended to be for the sole and exclusive
benefit of the parties hereto and their respective successors, and said
controlling persons and officers and directors and their heirs and legal
representatives, and for the benefit of no other person, firm or corporation. No
purchaser of Underwritten Securities from any Underwriter shall be deemed to be
a successor by reason merely of such purchase.

     SECTION 13. GOVERNING LAW. THIS UNDERWRITING AGREEMENT SHALL BE GOVERNED
BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

     SECTION 14. Effect of Headings. The Article and Section headings herein
and the Table of Contents are for convenience only and shall not affect the
construction hereof.


                                   * * * * *


                                      22
<PAGE>   26

     If the foregoing is in accordance with your understanding of our
agreement, please sign and return to the Company a counterpart hereof,
whereupon this Underwriting Agreement, along with all counterparts, will become
a binding agreement between the Underwriters and the Company in accordance with
its terms.

                                    Very truly yours,

                                    NOBLE DRILLING CORPORATION



                                    By: /s/ Robert D. Campbell  
                                        ---------------------------------------
                                        Robert D. Campbell
                                        President


CONFIRMED AND ACCEPTED,
as of the date first above written:

MERRILL LYNCH & CO.
MERRILL LYNCH, PIERCE, FENNER
& SMITH INCORPORATED


By: /s/ Robert A. Pacha                           
    -------------------------------
         Authorized Signatory



SALOMON SMITH BARNEY INC.


By: /s/  Andrew Safran                                       
    -------------------------------
         Authorized Signatory

For themselves and as Representatives
of the several Underwriters


                                      23
<PAGE>   27

                                 SCHEDULE A-1
                          6.95% SENIOR NOTES DUE 2009

<TABLE>
<CAPTION>
                                                                      PRINCIPAL
                                                                      AMOUNT OF
               NAME OF UNDERWRITER                                    2009 NOTES
               -------------------                                    ----------
<S>                                                                   <C>
Merrill Lynch, Pierce, Fenner & Smith                                 
      Incorporated .............................................     $  69,000,000

Salomon Smith Barney Inc. ......................................        69,000,000

Howard, Weil, Labouisse, Friedrichs Incorporated ...............         1,500,000

First Union Capital Markets Corp. ..............................         1,500,000

Simmons & Company International ................................         1,500,000

Dain Rauscher Wessels
      a division of Dain Rauscher Incorporated .................         1,500,000

Jefferies & Company, Inc. ......................................         1,500,000

Morgan Keegan & Company, Inc. ..................................         1,500,000

The Robinson-Humphrey Company, Inc. ............................         1,500,000

PaineWebber Incorporated .......................................         1,500,000
                                                                     -------------
Total ..........................................................     $ 150,000,000
                                                                     =============
</TABLE>


                                      24
<PAGE>   28

                                  SCHEDULE A-2
                          7.50% SENIOR NOTES DUE 2019


<TABLE>
<CAPTION>
                                                                      PRINCIPAL
                                                                      AMOUNT OF
               NAME OF UNDERWRITER                                    2009 NOTES
               -------------------                                    ----------
<S>                                                                   <C>
Merrill Lynch, Pierce, Fenner & Smith                                
      Incorporated .............................................     $ 115,000,000
                                                                                  
Salomon Smith Barney Inc. ......................................       115,000,000
                                                                     
Howard, Weil, Labouisse, Friedrichs Incorporated ...............         2,500,000
                                                                     
First Union Capital Markets Corp. ..............................         2,500,000               
                                                                     
Simmons & Company International ................................         2,500,000

Dain Rauscher Wessels
      a division of Dain Rauscher Incorporated .................         2,500,000
                                                                     
Jefferies & Company, Inc. ......................................         2,500,000
                                                                     
Morgan Keegan & Company, Inc. ..................................         2,500,000
                                                                     
The Robinson-Humphrey Company, Inc. ............................         2,500,000
                                                                     
PaineWebber Incorporated .......................................         2,500,000
                                                                     -------------
Total ..........................................................     $ 250,000,000
                                                                     =============
</TABLE>                                                             



                                      25
<PAGE>   29

                                  SCHEDULE B-1

                           NOBLE DRILLING CORPORATION

                          6.95% SENIOR NOTES DUE 2009


     1. The initial public offering price of the 2009 Notes shall be 99.929% of
the principal amount thereof, plus accrued interest, if any, from the date of
issuance.

     2. The purchase price to be paid by the Underwriters for the 2009 Notes
shall be 99.279% of the principal amount thereof.

     3. The interest rate on the 2009 Notes shall be 6.95% per annum.

     4. The premium to the Treasury Yield (as defined in the Indenture) used in
determining the Make-Whole Premium (as defined in the Indenture) on the 2009
Notes shall be 25 basis points.


                                      26
<PAGE>   30

                                  SCHEDULE B-2

                           NOBLE DRILLING CORPORATION

                          7.50% SENIOR NOTES DUE 2019


     1. The initial public offering price of the 2019 Notes shall be 100% of
the principal amount thereof, plus accrued interest, if any, from the date of
issuance.

     2. The purchase price to be paid by the Underwriters for the 2019 Notes
shall be 99.125% of the principal amount thereof.

     3. The interest rate on the 2019 Notes shall be 7.50% per annum.

     4. The premium to the Treasury Yield (as defined in the Indenture) used in
determining the Make-Whole Premium (as defined in the Indenture) on the 2019
Notes shall be 35 basis points.


                                      27
<PAGE>   31
                                                                      EXHIBIT A

                      FORM OF OPINION OF COMPANY'S COUNSEL
                          TO BE DELIVERED PURSUANT TO
                                  SECTION 5(b)

     (1) The Company has been duly incorporated and is validly existing as a
corporation in good standing under the laws of the State of Delaware.

     (2) The Company has corporate power and authority to own, lease and
operate its properties and to conduct its business as described in the
Prospectus and to enter into and perform its obligations under, or as
contemplated under, the Underwriting Agreement.

     (3) The Company is duly qualified as a foreign corporation to transact
business and is in good standing in each jurisdiction listed on an exhibit to
such opinion.

     (4) Each Subsidiary has been duly incorporated and is validly existing as
a corporation in good standing under the laws of the jurisdiction of its
incorporation, has corporate power and authority to own, lease and operate its
properties and to conduct its business as described in the Prospectus and is
duly qualified as a foreign corporation to transact business and is in good
standing in each jurisdiction listed on an exhibit to such opinion. Except as
otherwise described in the Prospectus, all of the issued and outstanding
capital stock of each Subsidiary has been duly authorized and is validly
issued, fully paid and non-assessable and, to the best of our knowledge, is
owned by the Company, directly or through subsidiaries, free and clear of any
security interest, mortgage, pledge, lien, encumbrance, claim or equity. None
of the outstanding shares of capital stock of any Subsidiary was issued in
violation of preemptive or other similar rights of any security holder of such
Subsidiary.

     (5) The authorized, issued and outstanding shares of capital stock of the
Company is as set forth in the column entitled "Actual" under the caption
"Capitalization" (except for subsequent issuances thereof, if any, pursuant to
reservations, agreements or employee benefit plans referred to in the
Prospectus or pursuant to the exercise of convertible securities or options
referred to in the Prospectus). Such shares of issued and outstanding capital
stock have been duly authorized and validly issued by the Company and are fully
paid and non-assessable, and none of the outstanding shares of capital stock of
the Company was issued in violation of preemptive or other similar rights of
any security holder of the Company.

     (6) The Underwriting Agreement has been duly authorized, executed and
delivered by the Company.

     (7) The Underwritten Securities have been duly authorized by the Company
for issuance and sale pursuant to the Underwriting Agreement. The Underwritten
Securities, when executed and authenticated in the manner provided for in the
Indenture (assuming the due authorization, execution


                                      A-1
<PAGE>   32
and delivery of the Indenture by the Trustee) and delivered against payment of
the consideration therefor specified in this Underwriting Agreement, will
constitute valid and binding obligations of the Company, enforceable against the
Company in accordance with their terms, except as the enforcement thereof may be
limited by bankruptcy, insolvency (including, without limitation, all laws
relating to fraudulent transfers), reorganization, moratorium or other similar
laws affecting the enforcement of creditors' rights generally or by general
equitable principles (regardless of whether enforcement is considered in a
proceeding in equity or at law). The Underwritten Securities are in the form
contemplated by, and each registered holder thereof is entitled to the benefits
of, the applicable Indenture.

     (8) The Indenture has been duly authorized, executed and delivered by the
Company and (assuming due authorization, execution and delivery thereof by the
applicable Trustee) constitutes a valid and binding agreement of the Company,
enforceable against the Company in accordance with its terms, except as the
enforcement thereof may be limited by (a) bankruptcy, insolvency, fraudulent
transfers or conveyances, reorganization, moratorium or other similar laws
affecting the enforcement of creditors' rights generally, (b) general equitable
principles (regardless of whether enforcement is considered in a proceeding in
equity or at law) and (c) an implied covenant of good faith and fair dealing.

     (9) The Underwritten Securities being sold pursuant to this Underwriting
Agreement and the Indenture conform in all material respects to the statements
relating thereto contained in the Prospectus and are in substantially the form
filed or incorporated by reference, as the case may be, as an exhibit to the
Registration Statement.

     (10) The statements made in the Prospectus under the caption "Description
of the Notes," "Description of Debt Securities" or any other caption purporting
to describe any such Securities, and in the Registration Statement under Item
15, to the extent that it constitutes matters of law, summaries of legal
matters or the Company's charter, bylaws or legal proceedings, or legal
conclusions fairly present in all material respects the information called for
with respect thereto by the 1933 Act Regulations.

     (11) To our knowledge, neither the Company nor any of its Subsidiaries is
in violation of its charter or by-laws and no default by the Company or any of
its Subsidiaries exists in the due performance or observance of any material
obligation, agreement, covenant or condition contained in any contract,
indenture, mortgage, loan agreement, note, lease or other agreement or
instrument that is described or referred to in the Registration Statement or
the Prospectus or filed or incorporated by reference as an exhibit to the
Registration Statement (except for any default which would not have a Material
Adverse Effect).

     (12) The execution, delivery and performance of the Underwriting
Agreement, and the Indenture and the consummation of the transactions
contemplated in the Underwriting Agreement and in the Registration Statement
and the Prospectus (including the issuance and sale of the Underwritten
Securities and the use of the proceeds from the sale of the Underwritten
Securities as 


                                      A-2
<PAGE>   33

described under the caption "Use of Proceeds" and the issuance of any
Underlying Securities) and compliance by the Company with its obligations
thereunder do not and will not, whether with or without the giving of notice or
passage of time or both, constitute a breach of, or default or Repayment Event
under, or result in the creation or imposition of any lien, charge or
encumbrance upon any assets or properties of the Company or any of its
Subsidiaries pursuant to, any contract, indenture, mortgage, deed of trust,
loan or credit agreement, note, lease or any other agreement or instrument,
known to us, to which the Company or any of its subsidiaries is a party or by
which it or any of them may be bound, or to which any of the assets or
properties of the Company or any of its Subsidiaries is subject (except for
such breaches or liens, charges or encumbrances that would not have a Material
Adverse Effect), nor will such action result in any violation of the provisions
of the charter or by-laws of the Company or any of its Subsidiaries organized
under the laws of any jurisdiction within the United States of America or any
applicable law, statute, rule, regulation, known to us, of any known to such
counsel, of the United States of America or the State of Texas or under the
Delaware General Corporation Law, or any administrative or court decree of any
government, government instrumentality or court, domestic or foreign, that
specifically names the Company or any Subsidiary or is directed to any of their
respective properties or assets known to such counsel, other than federal and
state laws, except as specifically addressed herein.

     (13) To the best of our knowledge, there is not pending or threatened any
action, suit, proceeding, inquiry or investigation to which the Company or any
of its subsidiaries is a party or to which the property of the Company or any
of its subsidiaries is subject, before or by any court or governmental agency
or body, domestic or foreign, required to be disclosed in the Registration
Statement, which is not adequately disclosed in the Prospectus or which might
reasonably be expected to result in a Material Adverse Effect, or which might
reasonably be expected to materially and adversely affect the consummation of
the transactions contemplated under the Underwriting Agreement, or the
Indenture or the performance by the Company of its obligations thereunder.

     (14) To the best of our knowledge, there are no franchises, contracts,
indentures, mortgages, loan agreements, notes, leases or other instruments
required to be described or referred to in the Prospectus or to be filed as
exhibits to the Registration Statement other than those described or referred
to therein or filed or incorporated by reference as exhibits thereto, and the
descriptions thereof or references thereto are correct in all material
respects.

     (15) The Registration Statement has been declared effective under the 1933
Act. Any required filing of the Prospectus pursuant to Rule 424(b) has been
made in the manner and within the time period required by Rule 424(b). To the
best of our knowledge, no stop order suspending the effectiveness of the
Registration Statement has been issued under the 1933 Act and no proceedings
for that purpose have been initiated or are pending or overtly threatened by
the Commission.

     (16) The Registration Statement and the Prospectus, excluding the
documents incorporated by reference therein, and each amendment or supplement
to the Registration Statement and Prospectus, excluding the documents
incorporated by reference therein, as of their respective


                                      A-3
<PAGE>   34

effective or issue dates (other than the financial statements and related
notes, the financial statement schedules and other financial data included
therein or omitted therefrom and the Trustee's Statement of Eligibility on Form
T-1 (the "Form T-1"), as to which we express no opinion), complied as to form
in all material respects with the requirements of the 1933 Act and the 1933 Act
Regulations.

     (17) The documents incorporated by reference in the Prospectus (other than
the financial statements and related notes, the financial statement schedules
and other financial data therein or incorporated by reference therein or
omitted therefrom, as to which we express no opinion), when they became
effective or were filed with the Commission, as the case may be, complied as to
form in all material respects with the requirements of the 1933 Act or the 1934
Act, as applicable, and the rules and regulations of the Commission thereunder.

     (18) No filing with, or authorization, approval, consent, license, order,
registration, qualification or decree of, any court or governmental authority
or agency, domestic or foreign, is necessary or required for the due
authorization, execution or delivery by the Company of the Underwriting
Agreement or for the performance by the Company of the transactions
contemplated under the Prospectus, the Underwriting Agreement or the Indenture,
other than under the 1933 Act, the 1933 Act Regulations, the 1939 Act and the
1939 Act Regulations and other than under foreign or state securities or Blue
Sky laws.

     (19) The Indenture has been duly qualified under the 1939 Act.

     (20) The Underwritten Securities, upon issuance, will be excluded or
exempted under, or beyond the purview of, the Commodity Exchange Act, as
amended (the "Commodity Exchange Act"), and the rules and regulations of the
Commodity Futures Trading Commission under the Commodity Exchange Act (the
"Commodity Exchange Act Regulations").

     (21) The Company is not, and upon the issuance and sale of the
Underwritten Securities as herein contemplated and the application of the net
proceeds therefrom as described in the Prospectus will not be, an "investment
company" within the meaning of the Investment Company Act of 1940, as amended
(the "1940 Act").

     In addition, such counsel has participated in conferences with directors,
officers and other representatives of the Company, representatives of the
independent public accountants for the Company, representatives of the
Underwriters and counsel for the Underwriters, at which conferences the
contents of the Registration Statement and the Prospectus and related matters
were discussed, and, although we have not independently verified and are not
passing upon and assume no responsibility for the accuracy, completeness or
fairness of the statements contained in the Registration Statement and
Prospectus (except to the extent specified elsewhere in this opinion), we
advise you that, on the basis of the foregoing, no facts have come to our
attention that would lead us to believe that the Registration Statement or any


                                      A-4
<PAGE>   35

post-effective amendment thereto (except for financial statements and schedules
and other financial data included therein or omitted therefrom and for the Form
T-1, as to which we make no statement), at the time the Registration Statement
or any post-effective amendment thereto (including the filing of the Company's
Annual Report on Form 10-K with the Commission) became effective or at the date
of this Underwriting Agreement, contained an untrue statement of a material
fact or omitted to state a material fact required to be stated therein or
necessary to make the statements therein not misleading or that the Prospectus
or any amendment or supplement thereto (except for financial statements and
schedules and other financial data included therein or omitted therefrom, as to
which we make no statement), at the time the Prospectus was issued, at the time
any such amended or supplemented prospectus was issued or at the Closing Time,
included or includes an untrue statement of a material fact or omitted or omits
to state a material fact necessary in order to make the statements therein, in
the light of the circumstances under which they were made, not misleading.

     In rendering such opinion, such counsel may rely (A) as to matters
involving the application of the laws of the Cayman Islands, upon the opinions
of Maples & Calder, special counsel to the Company (each of which opinions
shall be dated and furnished to the Underwriters at the Closing Time, shall be
reasonably satisfactory in form and substance to counsel for the Underwriters
and shall expressly state that the Underwriters may rely on such opinion s if
it were addressed to them), provided that Thompson & Knight P.C. shall state in
their opinion that they believe that they and the Underwriters are justified in
relying upon such opinion, and (B) as to matters of fact (but not as to legal
conclusions), to the extent they deem proper, on certificates of responsible
officers of the Company and public officials. Such opinion shall not state that
it is to be governed or qualified by, or that it is otherwise subject to, any
treatise, written policy or other document relating to legal opinions,
including, without limitation, the Legal Opinion Accord of the ABA Section of
Business Law (1991).

     With respect to opinions relating to the enforceability of the
Underwritten Securities and Indenture contained in paragraphs (7) and (8)
above, (i) Thompson & Knight P.C. may assume that for such purposes the laws of
the State of Texas are the same as the laws of the State of New York and (ii)
the Underwriters are also entitled to rely on an opinion of Andrews & Kurth
L.L.P. as to such matters under New York law.


                                      A-5

<PAGE>   1
                                                                    Exhibit 4.1

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







                           NOBLE DRILLING CORPORATION
                                     ISSUER


                                      AND


                   CHASE BANK OF TEXAS, NATIONAL ASSOCIATION
                                    TRUSTEE


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


                                   INDENTURE


                           DATED AS OF MARCH 1, 1999


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



                             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 MARCH 1, 1999


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

Section 310(a)(1)....................................................... 609

(a)(2).................................................................. 609

(a)(3).................................................................. Not Applicable

(a)(4).................................................................. Not Applicable

(b)..................................................................... 608, 610

Section 311(a).......................................................... 613

(b)..................................................................... 613

(c)..................................................................... Not Applicable

Section 312(a).......................................................... 701, 702(a)

(b)..................................................................... 702(b)

(c)..................................................................... 702(b)

Section 313(a).......................................................... 703(a)

(b)..................................................................... 703(a)

(c)..................................................................... 703(a)

(d)..................................................................... 703(b)

Section 314(a).......................................................... 704, 1005

(b)..................................................................... Not Applicable

(c)(1).................................................................. 103

(c)(2).................................................................. 103

(c)(3).................................................................. Not Applicable

(d)..................................................................... Not Applicable

(e)..................................................................... 103

Section 315(a).......................................................... 601(a)

(b)..................................................................... 602
</TABLE>


                                     -ii-
<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

Section 316(a)(1)(A).................................................... 502, 512

(a)(1)(B)............................................................... 513

(a)(2).................................................................. Not Applicable

(a) last sentence....................................................... 101

(b)..................................................................... 508

Section 317(a)(1)....................................................... 503

(a)(2).................................................................. 504

(b)..................................................................... 1003

Section 318(a).......................................................... 108
</TABLE>

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


                                     -iii-
<PAGE>   4
                              TABLE OF CONTENTS(1)


<TABLE>
<S>                                                                        <C>
RECITALS OF THE COMPANY.................................................    1

ARTICLE ONE--DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION....    1

SECTION 101. Definitions................................................    1
         Act............................................................    1
         Additional Amounts.............................................    2
         Affiliate......................................................    2
         Agent Members..................................................    2
         Authenticating Agent...........................................    2
         Authorized Newspaper...........................................    2
         Board of Directors.............................................    2
         Board Resolution...............................................    2
         Business Day...................................................    2
         Commission.....................................................    2
         Company........................................................    2
         Company Request................................................    2
         Company Order..................................................    2
         Conversion Event...............................................    2
         Corporate Trust Office.........................................    2
         Default........................................................    3
         Defaulted Interest.............................................    3
         Depositary.....................................................    3
         Dollar.........................................................    3
         Event of Default...............................................    3
         Exchange Rate..................................................    3
         Holder.........................................................    3
         Indenture......................................................    3
         Interest.......................................................    3
         Interest Payment Date..........................................    3
         Judgment Currency..............................................    3
         Maturity.......................................................    3
         Officers' Certificate..........................................    3
         Opinion of Counsel.............................................    3
         Original Issue Discount Security...............................    3
         Outstanding....................................................    3
         Paying Agent...................................................    4
         Person.........................................................    4
         Place of Payment...............................................    4
         Predecessor Security...........................................    4
         Redemption Date................................................    5
         Redemption Price...............................................    5
         Regular Record Date............................................    5
         Required Currency..............................................    5
         Responsible Officer............................................    5
         Securities.....................................................    5
</TABLE>

- --------------
   (1) 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>
         Security Custodian.............................................    5
         Security Register..............................................    5
         Special Record Date............................................    5
         Stated Maturity................................................    5
         Subsidiary.....................................................    5
         Trustee........................................................    5
         Trust Indenture Act............................................    5
         United States..................................................    5
         United States Alien............................................    6
         U.S. Government Obligations....................................    6
         Vice President.................................................    6
         Wholly Owned Subsidiary........................................    6
         Yield to Maturity..............................................    6

SECTION 102. Incorporation by Reference of Trust Indenture Act..........    6

SECTION 103. Compliance Certificates and Opinions.......................    6

SECTION 104. Form of Documents Delivered to Trustee.....................    7

SECTION 105. Acts of Holders; Record Dates..............................    7

SECTION 106. Notices, Etc., to Trustee and Company......................    8

SECTION 107. Notice to Holders; Waiver..................................    8

SECTION 108. Conflict With Trust Indenture Act..........................    9

SECTION 109. Effect of Headings and Table of Contents...................    9

SECTION 110. Successors and Assigns.....................................    9

SECTION 111. Separability Clause........................................    9

SECTION 112. Benefits of Indenture......................................    9

SECTION 113. Governing Law..............................................    9

SECTION 114. Legal Holidays.............................................    9

SECTION 115. Corporate Obligation.......................................   10

ARTICLE TWO--SECURITY FORMS.............................................   10

SECTION 201. Forms Generally............................................   10

SECTION 202. Form of Trustee's Certificate of Authentication............   10

SECTION 203. Securities in Global Form..................................   10

ARTICLE THREE--THE SECURITIES...........................................   13

SECTION 301. Amount Unlimited; Issuable in Series.......................   13

</TABLE>


                                      -v-
<PAGE>   6

<TABLE>
<S>                                                                        <C>
SECTION 302. Denominations..............................................   15

SECTION 303. Execution, Authentication, Delivery and Dating.............   15

SECTION 304. Temporary Securities.......................................   16

SECTION 305. Registration, Registration of Transfer and Exchange........   16

SECTION 306. Mutilated, Destroyed, Lost and Stolen Securities...........   17

SECTION 307. Payment of Interest; Interest Rights Preserved.............   18

SECTION 308. Persons Deemed Owners......................................   19

SECTION 309. Cancellation...............................................   19

SECTION 310. Computation of Interest....................................   19

SECTION 311. CUSIP Numbers..............................................   19

ARTICLE FOUR--SATISFACTION AND DISCHARGE................................   19

SECTION 401. Satisfaction and Discharge of Indenture....................   19

SECTION 402. Application of Trust Money.................................   21

SECTION 403. Discharge of Liability on Securities of Any Series.........   21

SECTION 404. Reinstatement..............................................   21

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...........................   24

SECTION 505. Trustee May Enforce Claims Without Possession of 
             Securities or Coupons......................................   25

SECTION 506. Application of Money Collected.............................   25

SECTION 507. Limitation on Suits........................................   26

SECTION 508. Unconditional Right of Holders to Receive Principal, 
             Premium and Interest.......................................   26

SECTION 509. Restoration of Rights and Remedies.........................   26

SECTION 510. Rights and Remedies Cumulative.............................   26

SECTION 511. Delay or Omission Not Waiver...............................   27
</TABLE>


                                     -vi-
<PAGE>   7

<TABLE>
<S>                                                                        <C>
SECTION 512. Control by Holders.........................................   27

SECTION 513. Waiver of Past Defaults....................................   27

SECTION 514. Undertaking for Costs......................................   27

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..................................   29

SECTION 604. Not Responsible for Recitals or Issuance of Securities.....   30

SECTION 605. May Hold Securities........................................   30

SECTION 606. Money Held in Trust........................................   30

SECTION 607. Compensation and Reimbursement.............................   30

SECTION 608. Disqualification; Conflicting Interests....................   31

SECTION 609. Corporate Trustee Required; Eligibility....................   31

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.....   35

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
</TABLE>


                                     -vii-
<PAGE>   8

<TABLE>
<S>                                                                        <C>
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

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......................................   43

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
</TABLE>


                                    -viii-
<PAGE>   9

<TABLE>
<S>                                                                        <C>
ARTICLE THIRTEEN--MEETINGS OF HOLDERS OF SECURITIES.....................    45

SECTION 1301. Purposes for Which Meetings May Be Called.................    45

SECTION 1302. Call, Notice and Place of Meetings........................    45

SECTION 1303. Persons Entitled to Vote at Meetings......................    45

SECTION 1304. Quorum; Action............................................    45

SECTION 1305. Determination of Voting Rights; Conduct and
              Adjournment of Meetings...................................    46

SECTION 1306. Counting Votes and Recording Action of Meetings...........    46
</TABLE>


                                     -ix-

<PAGE>   10

     INDENTURE, dated as of March 1, 1999, 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
Street, Suite 1150, Houston, Texas 77002, Attention: Corporate Trust
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.

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


                                      -1-
<PAGE>   11

     "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" means each Monday, Tuesday, Wednesday, Thursday and Friday
that is not a day on which banking institutions in the 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 Indenture 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.

     "Corporate Trust Office" means the principal office of the Trustee 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.


                                      -2-
<PAGE>   12
     "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.

     "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:

                                      -3-
<PAGE>   13


     (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.

     "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.


                                      -4-
<PAGE>   14


     "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 first day of the
calendar month of the month of 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.

     "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.


                                      -5-
<PAGE>   15


     "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.

     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.


                                      -6-
<PAGE>   16


     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 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

                                      -7-
<PAGE>   17

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

     (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

                                      -8-
<PAGE>   18

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.

     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


                                      -9-
<PAGE>   19

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.

     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

                                     -10-
<PAGE>   20

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 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.


                                     -11-
<PAGE>   21


     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 or at any time the Depositary ceases to be registered under the Exchange
Act, (2) an Event of Default, or an event which, with notice or the lapse of
time or both, would constitute 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 in its sole discretion that a global Security shall be
exchangeable for definitive Securities in registered form.

     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.



                                     -12-
<PAGE>   22


                                 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;

     (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

                                     -13-
<PAGE>   23

          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 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,


                                     -14-
<PAGE>   24

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.

     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,

                                     -15-
<PAGE>   25

          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.

     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


                                     -16-
<PAGE>   26

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.

     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

                                     -17-
<PAGE>   27

 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 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.


                                     -18-
<PAGE>   28


     SECTION 308. Person 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.

     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 comprising 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
               under the terms of an irrevocable trust agreement in form and
               substance satisfactory

                                     -19-
<PAGE>   29

               to the Trustee, as trust funds in trust solely for the benefit of
               the Holders of Outstanding Securities for that 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;

     (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.


                                     -20-
<PAGE>   30


     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,

     (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.


                                     -21-
<PAGE>   31


                                  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 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


                                     -22-
<PAGE>   32

     (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 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


                                     -23-
<PAGE>   33


          (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.

     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,


                                     -24-
<PAGE>   34


     (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 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
Business Day in the City of New York 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


                                     -25-
<PAGE>   35

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 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

                                     -26-
<PAGE>   36

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.

     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

                                     -27-
<PAGE>   37

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

          (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 

                                     -28-
<PAGE>   38

               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 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 


                                     -29-
<PAGE>   39

          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.

     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);


                                     -30-
<PAGE>   40

     (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.

     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


                                     -31-
<PAGE>   41

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

          (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


                                     -32-
<PAGE>   42

          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, 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.


                                     -33-
<PAGE>   43


     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 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.


                                     -34-
<PAGE>   44


     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
          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


                                     -35-
<PAGE>   45

          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)  either (a) the Company shall be the continuing corporation or (b) the
          Person (if other than the Company or any of its Subsidiaries) formed
          by such consolidation or into which the Company is merged, or the
          Person which acquires, by sale, lease, conveyance, transfer or other
          disposition, all or substantially all of the assets of the Company,
          shall be organized and validly existing under the laws of the United
          States of America, any political subdivision thereof or any state
          thereof or the District of Columbia, and shall expressly assume, by a
          supplemental indenture, the due and punctual payment of the principal
          of (and premium, if any,) and interest on or any Additional Amounts
          with respect to the Securities and the performance of the Company's
          covenants and obligations under this Indenture and the Securities.

     (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



                                     -36-
<PAGE>   46


     (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>   47

     (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.


                                     -38-
<PAGE>   48


     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 the Borough of Manhattan, City of New York,
an office or agency (which may be an office of the Trustee, the Registrar or
the Paying Agent) where Securities may be presented or surrendered for payment,
where Securities may be surrendered for registration of transfer or exchange
and where notices and demands to or upon the Company in respect of Securities
and this Indenture may be served. Unless otherwise designated by the Company by
written notice to the Trustee, such office or agency shall be the office of the
agent of the Trustee in the City of New York which, on the date hereof, is
located at 55 Water Street, North Building, Room 234, Windows 20 and 21, New
York, New York 10041, Attention: Corporate Trust Services. 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


                                     -39-
<PAGE>   49

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 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

                                     -40-
<PAGE>   50

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 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

                                     -41-
<PAGE>   51

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.

     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.



                                     -42-
<PAGE>   52





     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 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 


                                     -43-
<PAGE>   53



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.

     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.



                                     -44-
<PAGE>   54




                                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 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.


                                     -45-
<PAGE>   55



     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.

     (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 



                                     -46-
<PAGE>   56







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.


                                     -47-


<PAGE>   57

     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    /s/ Robert D. Campbell     
                                         ------------------------------------
                                         Name: Robert D. Campbell  
                                         Title: President  


                                   CHASE BANK OF TEXAS, NATIONAL ASSOCIATION


[CORPORATE SEAL]                   By    /s/ Mauri J. Cowen         
                                         ------------------------------------
                                         Name: Mauri J. Cowen      
                                         Title: Vice President and Trust Officer


                                     -48-

<PAGE>   1
                                                                     Exhibit 4.2

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







                           NOBLE DRILLING CORPORATION


                                      and


                   CHASE BANK OF TEXAS, NATIONAL ASSOCIATION


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


                          First Supplemental Indenture
                                  relating to

                                  $400,000,000

                  $150,000,000 of 6.95% Senior Notes due 2009
                  $250,000,000 of 7.50% Senior Notes due 2019

                           Dated as of March 16, 1999

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







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

<PAGE>   2

         FIRST SUPPLEMENTAL INDENTURE, dated as of March 16, 1999 and relating
to the 2009 Notes and the 2019 Notes referred to below (this "Supplemental
Indenture"), between NOBLE DRILLING CORPORATION, a corporation duly organized
and existing under the laws of the State of Delaware (the "Company"), 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 under this Supplemental Indenture and the Indenture referred to below
(the "Trustee"). Capitalized terms not otherwise defined in this Supplemental
Indenture have the meanings assigned to them in the Indenture referred to
below.

                              W I T N E S S E T H:

         WHEREAS, the Company has heretofore executed and delivered to the
Trustee an indenture dated as of March 1, 1999 (as amended, supplemented or
otherwise modified from time to time, the "Indenture") to provide for the
issuance from time to time of its unsecured senior debt securities (the
"Securities") the form and terms of which are to be established pursuant to
Articles Two and Three of the Indenture; and

         WHEREAS, Article Nine of the Indenture provides, among other things,
that the Company and the Trustee may enter into indentures supplemental to the
Indenture for, among other things, the purpose of establishing the form and
terms of the Securities of any series as permitted in Articles Two and Three of
the Indenture and otherwise amending the Indenture in a manner not prejudicial
to the interests of the Holders of the Securities of any series; and

         WHEREAS, the Company desires to create two series of Securities under
the Indenture in an aggregate principal amount of $400,000,000, comprising
$150,000,000 of 6.95% Senior Notes due 2009 (the "2009 Notes") and $250,000,000
of 7.50% Senior Notes due 2019 (the "2019 Notes," and together with the 2009
Notes, the "Notes"), in furtherance of which the Board of Directors of the
Company has adopted a Board Resolution authorizing the Company to enter into
this Supplemental Indenture without the consent of the Holders of the
Securities as provided for in Section 901 of the Indenture; and

         WHEREAS, all acts necessary to make the Notes, when executed by the
Company and authenticated and delivered by the Trustee as provided in the
Indenture, the valid and binding obligations of the Company and to make this
Supplemental Indenture a valid and binding agreement in accordance with Article
Nine of the Indenture have been duly performed and executed;



                                      -1-
<PAGE>   3

         NOW, THEREFORE, in consideration of the promises and mutual agreements
herein contained, the Company and the Trustee mutually covenant and agree for
the equal and proportionate benefit of the Holders from time to time of the
Notes as follows:

         SECTION 1. Issuance, Terms and Form of the 2009 Notes.

         1.1 Issuance of 2009 Notes. A series of Securities is hereby created
which shall be designated as the 6.95% Senior Notes due 2009 and shall be
referred to as the "2009 Notes." The aggregate principal amount of 2009 Notes
created hereby which may be authenticated and delivered under this Supplemental
Indenture shall not exceed $150,000,000, except as permitted under the terms of
the Indenture.

         1.2 Terms of the 2009 Notes. The 2009 Notes shall be executed,
authenticated and delivered in accordance with the provisions of, and shall in
all respects be subject to, the terms, conditions and covenants of the
Indenture and this Supplemental Indenture.

         1.3 Form of the 2009 Notes. The 2009 Notes shall be executed,
authenticated and delivered substantially in the form attached hereto as
Exhibit A, the terms of which are incorporated in this Supplemental Indenture
for all purposes.

         SECTION 2. Issuance, Terms and Form of the 2019 Notes.

         2.1 Issuance of 2019 Notes. A series of Securities is hereby created
which shall be designated as the 7.50% Senior Notes due 2019 and shall be
referred to as the "2019 Notes." The aggregate principal amount of 2019 Notes
created hereby which may be authenticated and delivered under this Supplemental
Indenture shall not exceed $250,000,000, except as permitted under the terms of
the Indenture.

         2.2 Terms of the 2019 Notes. The 2019 Notes shall be executed,
authenticated and delivered in accordance with the provisions of, and shall in
all respects be subject to, the terms, conditions and covenants of the
Indenture and this Supplemental Indenture.

         2.3 Form of the 2019 Notes. The 2019 Notes shall be executed,
authenticated and delivered substantially in the form attached hereto as
Exhibit B, the terms of which are incorporated in this Supplemental Indenture
for all purposes.

         SECTION 3. Separate Voting for Holders of the 2009 Notes and the 2019
Notes.

         3.1 Separate Voting. For purposes of interpreting the voting
provisions contained in Article Thirteen of the Indenture, and for all other
purposes, the 2009 Notes and the 2019 Notes 


                                      -2-
<PAGE>   4

shall vote as separate series of Securities. Therefore, the Holders of the 2009
Notes ("2009 Holders") and the Holders of the 2019 Notes ("2019 Holders") shall
vote separately.

         3.2 Meetings. When determining whether the Holders of an adequate
principal amount of Securities have voted to request a meeting pursuant to
Section 1302(b) of the Indenture, 2009 Holders shall have no right to vote for
a meeting of 2019 Holders and 2019 Holders shall have no right to vote for a
meeting of 2009 Holders.

         3.3 Quorum. When determining whether the Holders of an adequate
principal amount of Securities are present for purposes of determining the
existence of a quorum pursuant to Section 1304 of the Indenture, 2009 Holders
shall not count toward establishing a quorum of 2019 Holders and 2019 Holders
shall not count toward establishing a quorum of 2009 Holders.

         3.4 Resolutions. When determining whether the Holders of an adequate
principal amount of Securities have voted to adopt a resolution pursuant to
Section 1304 of the Indenture, 2009 Holders shall have no right to vote for
resolutions affecting the 2019 Notes and 2019 Holders shall have no right to
vote for resolutions affecting the 2009 Notes.

         SECTION 4. Amendments to the Indenture Relating to the Notes.

         4.1 Amendments to Article One of the Indenture (Definitions). Article
One of the Indenture is hereby amended in respect of, and applicable to, the
Notes and only in respect of, and applicable to, the Notes as follows:

          (a) by adding thereto the following new definitions in their
     appropriate alphabetical order:

          "Attributable Indebtedness," when used with respect to any
     Sale/Leaseback Transaction, means, as at the time of determination, the
     present value (discounted at the rate set forth or implicit in the terms
     of the lease included in such transaction) of the total obligations of the
     lessee for rental payments (other than amounts required to be paid on
     account of taxes, maintenance, repairs, insurance, assessments, utilities,
     operating and labor costs and other items which do not constitute payments
     for property rights) during the remaining term of the lease included in
     such Sale/Leaseback Transaction (including any period for which such lease
     has been extended). In the case of any lease which is terminable by the
     lessee upon the payment of a penalty, such net amount shall be the lesser
     of the net amount determined assuming termination upon the first day such
     lease may be terminated (in which case the net amount shall also include
     the amount of the penalty, but no rent shall be considered as required to
     be paid under such lease subsequent to the first date upon which it may be
     so terminated) or the net amount determined assuming no such termination.


                                      -3-
<PAGE>   5


          "Capitalized Lease Obligations" of any Person means the obligations
     of such Person to pay rent or other amounts under any lease of (or other
     arrangement conveying the right to use) real or personal property, or a
     combination thereof, which obligations are required to be classified and
     accounted for as capital leases on a balance sheet of such Person under
     generally accepted accounting principles, and the amount of such
     obligations shall be the capitalized amount thereof determined in
     accordance with generally accepted accounting principles.

          "Consolidated Net Tangible Assets" means the total amount of assets
     (less applicable reserves and other properly deductible items) after
     deducting (1) all current liabilities (excluding the amount of those which
     are by their terms extendable or renewable at the option of the obligor to
     a date more than 12 months after the date as of which the amount is being
     determined and current maturities of long-term debt) and (2) all goodwill,
     trade names, trademarks, patents, unamortized debt discount and expense and
     other like intangible assets, all as set forth on the most recent quarterly
     balance sheet of the Company and its consolidated Subsidiaries and
     determined in accordance with generally accepted accounting principles.

          "Funded Indebtedness" means all Indebtedness (including Indebtedness
     incurred under any revolving credit, letter of credit or working capital
     facility) that by its terms matures on, or that is renewable at the option
     of any obligor thereon to, a date more than one year after the date on
     which such Indebtedness is originally incurred.

          "Indebtedness" of any Person means, without duplication, (i) all
     indebtedness of such Person for 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), (ii) all obligations of such Person evidenced
     by bonds, debentures, notes or other similar instruments, (iii) all
     obligations of such Person in respect of letters of credit or other
     similar instruments (or reimbursement obligations with respect thereto),
     other than standby letters of credit, performance bonds and other
     obligations issued by or for the account of such Person in the ordinary
     course of business, to the extent not drawn or, to the extent drawn, if
     such drawing is reimbursed not later than the third Business Day following
     demand for reimbursement, (iv) all obligations of such Person to pay the
     deferred and unpaid purchase price of property or services, except trade
     payables and accrued expenses incurred in the ordinary course of business,
     (v) all Capitalized Lease Obligations of such Person, (vi) all
     Indebtedness of others secured by a Lien on any asset of such Person,
     whether or not such Indebtedness is assumed by such Person (provided that
     if the obligations so secured have not been assumed in full by such Person
     or are not otherwise such Person's legal liability in full, then such
     obligations shall be deemed to be in an amount equal to the greater of (a)
     the lesser of (1) the full amount of such obligations and (2) the fair
     market value of such assets, as determined in good faith by the Board of
     Directors of such Person, which determination shall be evidenced by a
     Board 

                                      -4-
<PAGE>   6

     Resolution, and (b) the amount of obligations as have been assumed by such
     Person or which are otherwise such Person's legal liability), and (vii) all
     Indebtedness of others (other than endorsements in the ordinary course of
     business) guaranteed by such Person to the extent of such guarantee.

          "Joint Venture" means any partnership, corporation or other entity in
     which up to and including 50 percent of the partnership interests,
     outstanding voting stock or other equity interests is owned, directly or
     indirectly, by the Company and/or one or more Subsidiaries.

          "Lien" means any mortgage, pledge, lien, encumbrance, charge or
     security interest. For purposes of the Indenture, the Company or any
     Subsidiary of the Company shall be deemed to own subject to a Lien any
     asset which it has acquired or holds subject to the interest of a vendor or
     lessor under any conditional sale agreement, Capitalized Lease Obligation
     or other title retention agreement relating to such asset.

          "Make-Whole Premium" with respect to any Note (or portion of a Note)
     to be redeemed shall equal the excess, if any, of:

               (i) the sum of the present values, calculated as of the
     Redemption Date, of:

               (A) each interest payment that, but for the redemption, would
          have been payable on the Note (or its portion) being redeemed on each
          Interest Payment Date occurring after the Redemption Date (excluding
          any accrued interest for the period before the Redemption Date); and

               (B) the principal amount that, but for the redemption, would
          have been payable at the final maturity of the Note (or its portion)
          being redeemed;

          over

               (ii) the principal amount of the Note (or its portion) being
     redeemed.

     The present values of interest and principal payments referred to in
     clause (i) above will be determined in accordance with generally accepted
     principles of financial analysis. Those present values will be calculated
     by discounting the amount of each payment of interest or principal from
     the date that such payment would have been payable, but for the
     redemption, to the Redemption Date at a discount rate equal to the
     Treasury Yield plus 25 basis points in the case of redemption of the 2009
     Notes and 35 basis points in the case of redemption of the 2019 Notes. The
     Make-Whole Premium will be calculated by an independent investment banking
     institution of national standing appointed by the Company, provided that
     if the 

                                      -5-
<PAGE>   7

     Company fails to make such appointment at least 45 Business Days prior to
     the Redemption Date, or if the institution so appointed is unwilling or
     unable to make the calculation, such calculation will be made by Merrill
     Lynch & Co. or, if that firm is unwilling or unable to make the
     calculation, by an independent investment banking institution of national
     standing appointed by the Trustee (in any such case, the "Independent
     Investment Banker").

          "Non-Recourse Indebtedness" means any Indebtedness of the Company or
     any Subsidiary in respect of which (a) the recourse of the holder of such
     Indebtedness, whether direct or indirect and whether contingent or
     otherwise, is effectively limited to (i) Liens on specified assets and
     (ii) in respect of Indebtedness of a Subsidiary, Liens on assets of the
     Subsidiary acquired after the date of original issuance of the Notes, and
     with respect to such Indebtedness of the Company or a Subsidiary, neither
     the Company nor any Subsidiary (other than the issuer of such
     Indebtedness) provides any credit support or is otherwise liable or
     obligated and (b) the occurrence of any event, or the existence of any
     condition under any agreement or instrument relating to such Indebtedness,
     shall not at any time have the effect of accelerating, or permitting the
     acceleration of, the maturity of any other Indebtedness of the Company or
     any of its Subsidiaries or otherwise permitting any such other Indebtedness
     to be declared due and payable, or to be required to be prepaid, purchased
     or redeemed, prior to the stated maturity thereof; provided that the
     Indebtedness of Noble Drilling (Paul Romano) Inc. existing on the date of
     original issuance of the Notes shall be Non-Recourse Indebtedness.

          "Pari Passu Indebtedness" means any Indebtedness of the Company,
     whether outstanding on the issue date of the Notes or thereafter created,
     incurred or assumed, unless, in the case of any particular Indebtedness,
     the instrument creating or evidencing the same or pursuant to which the
     same is outstanding expressly provides that such Indebtedness shall be
     subordinated in right of payment to the Notes.

          "Permitted Liens" means (i) Liens existing on the date of original
     issuance of a series of Notes; (ii) Liens on property or assets of, or any
     shares of stock of, or other equity interests in, or indebtedness of, any
     Person existing at the time such Person becomes a Subsidiary of the
     Company or at the time such Person is merged into or consolidated with the
     Company or any of its Subsidiaries or at the time of a sale, lease or
     other disposition of the properties of a Person (or a division thereof) as
     an entirety or substantially as an entirety to the Company or a
     Subsidiary; (iii) Liens in favor of the Company or any of its
     Subsidiaries; (iv) Liens in favor of governmental bodies to secure
     progress or advance payments; (v) Liens securing industrial revenue or
     pollution control bonds; (vi) Liens on property securing (a) all or any
     portion of the cost of acquiring, constructing, altering, improving or
     repairing any property or assets, real or personal, or improvements used
     or to be used in connection with such property or (b) Indebtedness
     incurred by the Company or any Subsidiary of the Company prior to or
     within one year after the later of the acquisition,

                                      -6-
<PAGE>   8

     the completion of construction, alteration, improvement or repair or the
     commencement of commercial operation thereof, which Indebtedness is
     incurred for the purpose of financing all or any part of the purchase price
     thereof or construction or improvements thereon; (vii) statutory liens or
     landlords', carriers', warehouseman's, mechanics', suppliers',
     materialmen's, repairmen's or other like Liens arising in the ordinary
     course of business and with respect to amounts not yet delinquent or being
     contested in good faith by appropriate proceedings; (viii) Liens on current
     assets of the Company or any Subsidiary securing Indebtedness of the
     Company or such Subsidiary, respectively; (ix) Liens on the stock,
     partnership or other equity interest of the Company or any Subsidiary in
     any Joint Venture or any Subsidiary that owns an equity interest in such
     Joint Venture to secure Indebtedness, provided the amount of such
     Indebtedness is contributed and/or advanced solely to such Joint Venture;
     and (x) any extensions, substitutions, replacements or renewals in whole or
     in part of a Lien enumerated in clauses (i) through (ix) above.

          "Principal Property" means any drilling rig or drillship, or integral
     portion thereof, owned or leased by the Company or any Subsidiary and used
     for drilling offshore oil and gas wells, which, in the opinion of the Board
     of Directors, is of material importance to the business of the Company and
     its Subsidiaries taken as a whole, but no such drilling rig or drillship,
     or portion thereof, shall be deemed of material importance if its net book
     value (after deducting accumulated depreciation) is less than two percent
     of Consolidated Net Tangible Assets.

          "Sale/Leaseback Transaction" means any arrangement with any Person
     pursuant to which the Company or any Subsidiary leases any Principal
     Property that has been or is to be sold or transferred by the Company or
     the Subsidiary to such Person, other than (1) temporary leases for a term,
     including renewals at the option of the lessee, of not more than five
     years, (2) leases between the Company and a Subsidiary or between
     Subsidiaries, (3) leases of Principal Property executed by the time of, or
     within 12 months after the later of, the acquisition, the completion of
     construction, alteration, improvement or repair or the commencement of
     commercial operation of the Principal Property, and (4) arrangements
     pursuant to any provision of law with an effect similar to the former
     Section 168(f) of the Internal Revenue Code of 1954.

          "Treasury Yield" means a rate of interest per annum equal to the
     weekly average yield to maturity of United States Treasury Notes that have
     a constant maturity that corresponds to the remaining terms to maturity of
     the Notes, calculated to the nearest 1/12th of a year (the "Remaining
     Term"). The Treasury Yield will be determined as of the third Business Day
     immediately before the applicable Redemption Date. The weekly average
     yields of United States Treasury Notes will be determined by referring to
     the most recent statistical release published by the Federal Reserve Bank
     of New York and designated "H.15(519) Selected Interest Rates" or any
     successor release (the "H.15 Statistical Release"). 


                                      -7-
<PAGE>   9


     If the H.15 Statistical Release contains a weekly average yield for United
     States Treasury Notes having a constant maturity that is the same as the
     Remaining Term, then the Treasury Yield will be equal to that weekly
     average yield. In all other cases, the Treasury Yield will be calculated by
     interpolation, on a straight-line basis, between the weekly average yields
     on the United States Treasury Notes that have a constant maturity closest
     to and greater than the Remaining Term and the United States Treasury Notes
     that have a constant maturity closest to and less than the Remaining Term
     (in each case as set forth in the H.15 Statistical Release). Any weekly
     average yields as calculated by interpolation will be rounded to the
     nearest 1/100th of 1% with any figure of 1/200% or above being rounded
     upward. If weekly average yields for United States Treasury Notes are not
     available in the H.15 Statistical Release or otherwise, then the Treasury
     Yield will be calculated by interpolation of comparable rates selected by
     the Independent Investment Banker.

          (b) by deleting the definitions of "Redemption Price" and
     "Subsidiary" and replacing them as follows:

          "Redemption Price" shall be the price equal to 100% of the principal
     amount of the Notes being redeemed plus accrued interest to the Redemption
     Date (subject to the right of holders of record on the relevant record date
     to receive interest due on an interest payment date that is on or prior to
     the Redemption Date), plus the Make-Whole Premium applicable to such series
     of Notes, if any is required to be paid. The Redemption Price will not ever
     be less than 100% of the principal amount of the Notes being redeemed plus
     accrued interest to the Redemption Date.

          "Subsidiary" means, with respect to the Company at any date, any
     corporation, limited liability company, partnership, association or other
     entity the accounts of which would be consolidated with those of the
     Company in the Company's consolidated financial statements if such
     financial statements were prepared in accordance with generally accepted
     accounting principles as of such date, as well as any other corporation,
     limited liability company, partnership, association or other entity (a) of
     which securities or other ownership interests representing more than 50%
     of the equity or more than 50% of the ordinary voting power or, in the
     case of a partnership, more than 50% of the general partnership interests
     are, as of such date, owned, controlled or held, or (b) that is, as of
     such date, otherwise controlled, by the Company or one or more
     Subsidiaries of the Company.

         4.2 Amendments to Article Ten of the Indenture (Covenants of the
Company). Article Ten of the Indenture is hereby amended in respect of, and
applicable to, the Notes and only in respect of, and applicable to, the Notes
by adding thereto the following new Sections 1008 and 1009:



                                      -8-
<PAGE>   10

          SECTION 1008. Limitations on Liens. The Company will not, and will
     not permit any of its Subsidiaries to, issue, assume or guarantee any
     Indebtedness for borrowed money secured by any Lien upon any Principal
     Property or any shares of stock or indebtedness of any Subsidiary that
     owns or leases a Principal Property (whether such Principal Property,
     shares of stock or indebtedness are now owned or hereafter acquired)
     without making effective provision whereby the Notes (together with, if
     the Company shall so determine, any other Indebtedness or other
     obligation) shall be secured equally and ratably with (or, at the option
     of the Company, prior to) the Indebtedness so secured for so long as such
     Indebtedness is so secured. The foregoing restrictions do not, however,
     apply to Indebtedness secured by Permitted Liens.

          Notwithstanding the foregoing, the Company and its Subsidiaries may,
     without securing the Notes, issue, assume or guarantee secured
     Indebtedness that would otherwise be subject to the foregoing restrictions
     in an aggregate principal amount that, together with all other such
     Indebtedness of the Company and its Subsidiaries that would otherwise be
     subject to the foregoing restrictions (including Indebtedness permitted to
     be secured under clause (i) under the definition of Permitted Liens but
     excluding Indebtedness permitted to be secured under clauses (ii) through
     (x) thereunder) and the aggregate amount of Attributable Indebtedness
     deemed outstanding with respect to Sale/Leaseback Transactions (other than
     those in connection with which the Company has voluntarily retired any of
     the Notes, any Pari Passu Indebtedness or any Funded Indebtedness pursuant
     to clause (c) of Section 1009 captioned "Limitation on Sale/Leaseback
     Transactions"), does not at any one time exceed 15 percent of Consolidated
     Net Tangible Assets of the Company and its consolidated subsidiaries.

          SECTION 1009. Limitation on Sale/Leaseback Transactions. The Company
     will not, and will not permit any Subsidiary to, enter into any
     Sale/Leaseback Transaction with any person (other than the Company or a
     Subsidiary) unless: (a) the Company or such Subsidiary would be entitled
     to incur Indebtedness in a principal amount equal to the Attributable
     Indebtedness with respect to such Sale/Leaseback Transaction secured by a
     Lien on the property subject to such Sale/Leaseback Transaction pursuant
     to the covenant contained in Section 1008 captioned "Limitations on Liens"
     without equally and ratably securing the Notes pursuant to such covenant;
     (b) after the date of the first series of Notes issued under the Indenture
     and within a period commencing nine months prior to the consummation of
     such Sale/Leaseback Transaction and ending nine months after the
     consummation thereof, the Company or such Subsidiary shall have expended
     for property used or to be used in the ordinary course of business of the
     Company and its Subsidiaries an amount equal to all or a portion of the
     net proceeds of such Sale/Leaseback Transaction and the Company shall have
     elected to designate such amount as a credit against such Sale/Leaseback
     Transaction (with any such amount not being so designated to be applied as
     set forth in clause (c) below or as otherwise permitted); or (c) the
     Company, during the nine-

                                      -9-
<PAGE>   11

     month period after the effective date of such Sale/Leaseback Transaction,
     shall have applied to either (i) the voluntary defeasance or retirement of
     any Notes, any Pari Passu Indebtedness or any Funded Indebtedness or (ii)
     the acquisition of one or more Principal Properties at fair value, an
     amount equal to the greater of the net proceeds of the sale or transfer of
     the property leased in such Sale/Leaseback Transaction and the fair value,
     as determined by the Board of Directors, of such property as the time of
     entering into such Sale/Leaseback Transaction (in either case adjusted to
     reflect the remaining term of the lease and any amount expended by the
     Company as set forth in clause (b) above), less an amount equal to the sum
     of the principal amount of Notes, Pari Passu Indebtedness and Funded
     Indebtedness voluntarily defeased or retired by the Company plus any amount
     expended to acquire any Principal Properties at fair value, within such
     nine-month period and not designated as a credit against any other
     Sale/Leaseback Transaction entered into by the Company or any Subsidiary
     during such period.

         4.3 Amendments to Article Five of the Indenture (Events of Default).
Article Five of the Indenture is hereby amended in respect of, and applicable
to, the Notes and only in respect of, and applicable to, the Notes by:

          (a) deleting in its entirety clause (1) of Section 501 of the
     Indenture and substituting in lieu thereof the following new clause (1):

               "(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 30 days; or" and

          (b) providing that in accordance with clause (7) of Section 501 of
     the Indenture the following shall constitute an Event of Default with
     respect to the 2009 Notes or the 2019 Notes, as the case may be:

               default under any bond, debenture, note or other evidence of
          Indebtedness (other than Non-Recourse Indebtedness) by either of the
          Company or any Subsidiary or under any mortgage, indenture or
          instrument under which there may be issued or by which there may be
          secured or evidenced any Indebtedness (other than Non-Recourse
          Indebtedness) of either of the Company or any Subsidiary resulting in
          the acceleration of such Indebtedness (other than Non-Recourse
          Indebtedness), or any default in payment of such Indebtedness (other
          than Non-Recourse Indebtedness) (after expiration of any applicable
          grace periods and presentation of any debt instruments, if required),
          if the aggregate amount of all such Indebtedness (other than
          Non-Recourse Indebtedness) that has been so accelerated and with
          respect to which there has been such a default in payment shall
          exceed $25,000,000 and there has been 







                                     -10-
<PAGE>   12



          a failure to obtain rescission or annulment of all such accelerations
          or to discharge all such defaulted indebtedness within 20 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 Notes of such series
          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.

          4.4 Amendments to Article Eleven of the Indenture (Redemption of
Securities). Article Eleven of the Indenture is hereby amended in respect of,
and applicable to, the Notes and only in respect of, and applicable to, the
Notes by deleting Sections 1102, 1103, 1105 and 1106 therefrom in their
entirety and substituting in lieu thereof the following new Sections 1102,
1103, 1105 and 1106:

          SECTION 1102. Election to Redeem; Notice to Trustee. The election of
     the Company to redeem any Notes shall be evidenced by a Board Resolution,
     a certified copy of which is delivered to the Trustee. In case of any
     redemption at the election of the Company, the Company shall, at least 45
     days prior to the Redemption Date fixed by it (unless a shorter notice
     period shall be satisfactory to the Trustee), notify the Trustee of such
     Redemption Date and of the series and aggregate principal amount of Notes
     to be redeemed.

          SECTION 1103. Selection by Trustee of Notes to Be Redeemed. If less
     than all of the 2009 Notes or 2019 Notes are to be redeemed, the
     particular Notes or portions thereof to be redeemed shall be selected not
     more than 60 days prior to the Redemption Date by the Trustee from the
     Outstanding 2009 Notes or 2019 Notes, as the case may be, not previously
     called for redemption, either pro rata, by lot or by another method the
     Trustee shall deem fair 
     and reasonable, and the aggregate principal amounts to be redeemed may be
     equal to $1,000 or any integral multiple thereof.

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

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

          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 




                                     -11-
<PAGE>   13






     a trust as provided in Section 1003) an amount of money sufficient to pay
     the Redemption Price of all the Notes that are to be redeemed on that date.

          SECTION 1106. Notes Payable on Redemption Date. Notice of redemption
     having been given as aforesaid, the Notes 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) such Notes shall cease to accrue
     interest. Upon surrender of any such Note for redemption in accordance
     with said notice, such Notes shall be paid by the Company at the
     Redemption Price.

          If any Notes called for redemption shall not be so paid upon
     surrender thereof for redemption, the Redemption Price thereof shall
     accrue interest at the rate of 6.95% per annum in the case of the 2009
     Notes and 7.50% per annum in the case of the 2019 Notes.

     SECTION 5. Miscellaneous.

     5.1 The Trustee. The recitals contained herein shall be taken as the
statements of the Company and the Trustee shall not assume responsibility for,
or be liable in respect of, the correctness thereof. The Trustee makes no
representation as to, and shall not be liable or responsible for, the validity
or sufficiency of this Supplemental Indenture.

     5.2 Limited Effect. Except as expressly amended hereby, all of the
provisions, covenants, terms and conditions of the Indenture are ratified and
confirmed, and shall remain in full force.

     5.3 Counterparts. This Supplemental Indenture may be executed by one or
more parties hereto on any number of separate counterparts, and all of said
counterparts taken together shall be deemed to constitute one and the same
instrument.

         5.4 GOVERNING LAW. THIS SUPPLEMENTAL INDENTURE SHALL BE DEEMED TO BE A
CONTRACT UNDER THE LAWS OF THE STATE OF NEW YORK AND FOR ALL PURPOSES SHALL BE
GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF SUCH STATE, WITHOUT
REGARD TO PRINCIPLES OF CONFLICTS OF LAWS.


                                     -12-
<PAGE>   14

         IN WITNESS WHEREOF, the parties hereto have caused this Supplemental
Indenture to be duly executed, all as of the date first above written.

                                        NOBLE DRILLING CORPORATION
                                        (the "Company")


                                        By: /s/ Robert D. Campbell
                                            --------------------------------
                                            Robert D. Campbell
                                            President


Attest: /s/ Byron L. Welliver                    
        ----------------------------------------
        Title: Senior Vice President -
               Finance, Treasurer and Controller

                                        CHASE BANK OF TEXAS, NATIONAL
                                        ASSOCIATION, as Trustee


                                        By: /s/ Mauri J. Cowen   
                                            --------------------------------
                                            Title: Vice President and Trust 
                                                   Officer


Attest:  /s/ Lori Knight                         
        ----------------------------------------
         Title: Administrator



                                     -13-
<PAGE>   15

                                                                      EXHIBIT A

                              [FORM OF 2009 NOTE]

               UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED
               REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW 
               YORK CORPORATION ("DTC"), TO ISSUER OR ITS AGENT FOR
               REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT, AND ANY
               CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO.
               OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED
               REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO CEDE &
               CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED
               REPRESENTATIVE OF DTC). ANY TRANSFER, PLEDGE, OR OTHER USE
               HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL
               INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
               INTEREST HEREIN.



                           NOBLE DRILLING CORPORATION

                           6.95% SENIOR NOTE DUE 2009
                                  $150,000,000

No. G-1
CUSIP No. 655042AC3
Issue Date:  March 16, 1999

         Noble Drilling Corporation, a Delaware corporation (the "Company"),
promises to pay to CEDE & CO. or its registered assigns, the principal amount
of _________________________________ MILLION DOLLARS ($__________________) on
March 15, 2009. This 2009 Note shall not bear interest except as specified on
the other side of this 2009 Note. Additional provisions of this 2009 Note are
set forth on the other side of this 2009 Note.

         IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed under its corporate seal.

                                      NOBLE DRILLING CORPORATION



                                      By: 
                                         --------------------------------------
                                            Title:


                                      A-1
<PAGE>   16

                    TRUSTEE'S CERTIFICATE OF AUTHENTICATION

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

Dated: March _____, 1999                   CHASE BANK OF TEXAS, NATIONAL
                                           ASSOCIATION, as Trustee


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


                                      A-2
<PAGE>   17

                      [FORM OF REVERSE SIDE OF 2009 NOTE]

                           6.95% SENIOR NOTE DUE 2009

         1. INTEREST. Commencing March 16, 1999, interest on this 2009 Note
will accrue at the rate of 6.95% per annum and will be payable in cash
semiannually on each March 15 and September 15, commencing September 15, 1999,
to 2009 Holders of record on the close of business on the immediately preceding
March 1 and September 1. All such interest shall be payable on demand.

         2. METHOD OF PAYMENT. Subject to the terms and conditions of the
Indenture, payments in respect of the 2009 Notes shall be made at the office or
agency of the Company maintained for that purpose in the City and State of New
York. The Company will pay cash amounts in money of the United States that at
the time of payment is legal tender for payment of public and private debts.

         3. PAYING AGENT AND SECURITY REGISTRAR. Initially, Chase Bank of
Texas, National Association, as Trustee (the "Trustee"), will act as Paying
Agent and Security Registrar. The Company may appoint and change any paying
agent or security registrar without notice, other than notice to the Trustee.
The Company or any of its Subsidiaries or any of their Affiliates may act as
Paying Agent or Security Registrar.

         4. INDENTURE. The Company issued the 2009 Notes under an Indenture,
dated as of March 1, 1999, between the Company and the Trustee, as supplemented
by a First Supplemental Indenture, dated as of March 16, 1999 (collectively,
the "Indenture"). The terms of the 2009 Notes include those stated in the
Indenture and those made part of the Indenture by reference to the Trust
Indenture Act of 1939, as amended (the "Trust Indenture Act of 1939").
Capitalized terms used herein and not defined herein have the meanings ascribed
thereto in the Indenture. The 2009 Notes are subject to all such terms, and
2009 Holders are referred to the Indenture and the Trust Indenture Act of 1939
for a statement of those terms.

         The 2009 Notes are general unsecured obligations of the Company,
limited to $150,000,000 aggregate principal amount.

         5. REDEMPTION AT THE OPTION OF THE COMPANY. No sinking fund is
provided for the 2009 Notes. The 2009 Notes will be subject to redemption at
the option of the Company, in whole or in part, at any time and from time to
time, upon not less than 30 nor more than 60 days' notice, at the Redemption
Price (as defined below).

         If notice of redemption has been given as provided in Article Eleven
of the Indenture and funds for the redemption of any 2009 Notes called for
redemption shall have been made 

                                      A-3
<PAGE>   18

available on the Redemption Date referred to in such notice, such 2009 Notes
will cease to bear interest on the date fixed for such redemption specified in
such notice and the only right of the Holders of the 2009 Notes from and after
the Redemption Date will be to receive payment of the Redemption Price upon
surrender of such 2009 Notes in accordance with such notice.

          As used herein:

          "Make-Whole Premium" with respect to any 2009 Note (or portion of a
2009 Note) to be redeemed shall equal the excess, if any, of:

     (i) the sum of the present values, calculated as of the Redemption Date,
of:

          (A) each interest payment that, but for the redemption, would have
     been payable on the 2009 Note (or its portion) being redeemed on each
     Interest Payment Date occurring after the Redemption Date (excluding any
     accrued interest for the period before the Redemption Date); and

          (B) the principal amount that, but for the redemption, would have been
     payable at the final maturity of the 2009 Note (or its portion) being
     redeemed;

     over

     (ii) the principal amount of the 2009 Note (or its portion) being redeemed.

          The present values of interest and principal payments referred to in
clause (i) above will be determined in accordance with generally accepted
principles of financial analysis. Those present values will be calculated by
discounting the amount of each payment of interest or principal from the date
that such payment would have been payable, but for the redemption, to the
Redemption Date at a discount rate equal to the Treasury Yield plus 25 basis
points for such 2009 Notes. The Make-Whole Premium will be calculated by an
independent investment banking institution of national standing appointed by
the Company, provided that if the Company fails to make such appointment at
least 45 Business Days prior to the Redemption Date, or if the institution so
appointed is unwilling or unable to make the calculation, such calculation will
be made by the Independent Investment Banker.

          "Redemption Price," with respect to 2009 Notes being redeemed on a
Redemption Date, shall be the price equal to 100% of the principal amount
thereof plus accrued interest to the Redemption Date (subject to the right of
holders of record on the relevant record date to receive interest due on an
Interest Payment Date that is on or prior to the Redemption Date), plus a
Make-Whole Premium, if any is required to be paid. The Redemption Price of any
2009 Notes being 




                                      A-4
<PAGE>   19





redeemed will not ever be less than 100% of the principal amount of such 2009
Notes plus accrued interest thereon to the Redemption Date.

          If less than all the 2009 Notes are to be redeemed, the particular
2009 Notes or portions thereof to be redeemed shall be selected not more than
60 days prior to the Redemption 

Date by the Trustee from the Outstanding 2009 Notes not previously called for
redemption, either pro rata, by lot or by another method the Trustee shall deem
fair and reasonable, and the aggregate principal amounts to be redeemed must be
equal to $1,000 or any integral multiple thereof.

          6. DENOMINATIONS; TRANSFER; EXCHANGE. The 2009 Notes are in
registered form, without coupons, in denominations of $1,000 of principal
amount and integral multiples of $1,000. A 2009 Holder may register the
transfer of or exchange 2009 Notes in accordance with the Indenture. The
Security Registrar may require a 2009 Holder, among other things, to furnish
appropriate endorsements and transfer documents and to pay any taxes and fees
required by law or permitted by the Indenture. The Company shall not be
required to exchange or register a transfer of (a) any 2009 Notes for a period
of 15 days next preceding the first mailing or publication of notice of
redemption of 2009 Notes to be redeemed or (b) any 2009 Notes selected, called
or being called for redemption, in whole or in part, except, in the case of any
2009 Note to be redeemed in part, the portion thereof not so to be redeemed.

          7. PERSONS DEEMED OWNERS. The registered Holder of this 2009 Note may
be treated as the owner of this 2009 Note for all purposes.

          8. UNCLAIMED MONEY. The Trustee and each Paying Agent shall each
return to the Company upon written request any money held by them for the
payment of any amount with respect to the 2009 Notes that remains unclaimed for
two years. After return to the Company, 2009 Holders entitled to the money must
look to the Company for payment as general creditors unless an applicable
abandoned property law designates another person.

          9. AMENDMENT; WAIVER. Subject to certain exceptions set forth in the
Indenture, (i) the Indenture or the 2009 Notes may be amended with the written
consent of the Holders of a majority in aggregate principal amount of the 2009
Notes at the time Outstanding and (ii) certain defaults or noncompliance with
certain provisions may be waived with the written consent of the Holders of a
majority in aggregate principal amount of the 2009 Notes at the time
Outstanding. Subject to certain exceptions set forth in the Indenture, without
the consent of any 2009 Holder, the Company and the Trustee may amend the
Indenture or the 2009 Notes to cure any ambiguity, defect or inconsistency, or
to comply with Article Nine of the Indenture, or to make any change that does
not adversely affect the rights of any Holder of 2009 Notes.

          10. DEFAULTS AND REMEDIES. Under the Indenture, Events of Default
include, among others, (a) default in 





                                      A-5
<PAGE>   20



the payment of principal or premium, if any, when due; (b) default in the
payment of any installment of interest when due, continued for 30 days; (c)
default in the performance of any other covenant of the Company applicable to
the 2009 Notes, continued for 90 days after written notice given in accordance
with the Indenture to the Company by the Trustee or to the Company and the
Trustee, by the Holders of at least 25% in aggregate principal amount of the
2009 Notes then Outstanding requiring the same to be remedied; (d) certain
events of bankruptcy, insolvency or reorganization of the Company; and (e)
default under any bond, debenture, note or other evidence of Indebtedness (other
than Non-Recourse Indebtedness) by either of the Company or any Subsidiary or
under any mortgage, indenture or instrument under which there may be issued or
by which there may be secured or evidenced any Indebtedness (other than
Non-Recourse Indebtedness) of either of the Company or any Subsidiary resulting
in the acceleration of such Indebtedness (other than Non-Recourse Indebtedness),
or any default in payment of such Indebtedness (other than Non-Recourse
Indebtedness) (after expiration of any applicable grace periods and presentation
of any debt instruments, if required), if the aggregate amount of all such
Indebtedness (other than Non-Recourse Indebtedness) that has been so accelerated
and with respect to which there has been such a default in payment shall exceed
$25,000,000 and there has been a failure to obtain rescission or annulment of
all such accelerations or to discharge all such defaulted indebtedness within 20
days after there has been given in accordance with the Indenture to the Company
by the Trustee or to the Company and the Trustee by the Holders of at least 25%
in principal amount of the 2009 Notes 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.

          If any Event of Default shall occur and be continuing, the Trustee or
the Holders of not less than 25% in aggregate principal amount of the 2009
Notes then Outstanding, by notice in writing to the Company (and to the
Trustee, if given by the 2009 Holders), may declare the principal of all of the
2009 Notes and the interest, if any, accrued thereon to be due and payable
immediately; provided, however, that the Holders of a majority in aggregate
principal amount of the 2009 Notes then Outstanding, by notice in writing to
the Company and the Trustee, may rescind and annul such declaration and its
consequences if all defaults under such Indenture are cured or waived.

          No Holder of 2009 Notes then Outstanding may institute any suit,
action or proceeding with respect to, or otherwise attempt to enforce, the
Indenture, unless (i) such Holder previously shall have given to the Trustee
written notice of default and of the continuance thereof, (ii) the Holders of
not less than 25% in aggregate principal amount of the 2009 Notes then
Outstanding shall have made written request to the Trustee to institute such
suit, action or proceeding and shall have offered to the Trustee such
reasonable indemnity as it may require with respect thereto and (iii) the
Trustee for 60 days after its receipt of such notice, request and offer of
indemnity, shall have neglected or refused to institute any such action, suit
or proceeding; provided that, the right of any Holder of any 2009 Note to
receive payment of the principal of, premium, if any, or interest, if any, on
such 2009 Note, on or after the respective due dates, or to institute suit for
the enforcement of any such payment shall not be impaired or affected without
the consent of such Holder. The Holders of a majority in aggregate principal
amount of the 2009 Notes then Outstanding may direct





                                      A-6
<PAGE>   21




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 with
respect to the 2009 Notes, provided that the Trustee may decline to follow such
direction if the Trustee determines that such action or proceeding is unlawful
or would involve the Trustee in personal liability.

          The Company is required to furnish to the Trustee annually a
certificate as to compliance by the Company with all conditions and covenants
under the Indenture.

          11. TRUSTEE DEALINGS WITH THE COMPANY. Subject to certain limitations
imposed by the Trust Indenture Act of 1939 and the Indenture, the Trustee under
the Indenture, in its individual or any other capacity, may become the owner or
pledgee of 2009 Notes and may otherwise deal with and collect obligations owed
to it by the Company or its Affiliates and may otherwise deal with the Company
or its Affiliates with the same rights it would have if it were not Trustee.

          12. NO RECOURSE AGAINST OTHERS. A director, officer, employee or
stockholder, as such, of the Company shall not have any liability for any
obligations of the Company under the 2009 Notes or the Indenture or for any
claim based on, in respect of or by reason of such obligations or their
creation. By accepting a 2009 Note, each 2009 Holder waives and releases all
such liability. The waiver and release are part of the consideration for the
issue of the 2009 Notes.

          13. AUTHENTICATION. This 2009 Note shall not be valid until an
authorized signatory of the Trustee manually signs the Trustee's Certificate of
Authentication on the other side of this 2009 Note.

          14. DEFEASANCE, COVENANT DEFEASANCE. The 2009 Notes are subject to
defeasance and covenant defeasance as provided in the Indenture.

          15. ABBREVIATIONS. Customary abbreviations may be used in the name of
a Holder of 2009 Notes or an assignee, such as TEN COM (= tenants in common),
TEN ENT (= tenants by the entireties), JT TEN (= joint tenants with right of
survivorship and not as tenants in common), CUST (= custodian), and U/G/M/A (=
Uniform Gift to Minors Act).

          16. GOVERNING LAW. THIS 2009 NOTE AND THE INDENTURE SHALL BE GOVERNED
BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK, AS
APPLIED TO CONTRACTS MADE AND PERFORMED WITHIN THE STATE OF NEW YORK, WITHOUT
REGARD TO PRINCIPLES OF CONFLICTS OF LAW.


                                      A-7
<PAGE>   22


          The Company will furnish to any Holder of 2009 Notes upon written
request and without charge a copy of the Indenture. Requests may be made to:
Noble Drilling Corporation, 10370 Richmond Avenue, Suite 400, Houston, Texas
77042, Attention: Corporate Secretary.


                                      A-8

<PAGE>   23

                                                                      EXHIBIT B

                              [FORM OF 2019 NOTE]

          UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE
          OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO
          ISSUER OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR
          PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE
          & CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED
          REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO CEDE & CO. OR TO
          SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF
          DTC). ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR
          OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED
          OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.



                           NOBLE DRILLING CORPORATION

                           7.50% SENIOR NOTE DUE 2019
                                  $250,000,000


No. G-1
CUSIP No. 655042AD1
Issue Date:  March 16, 1999

          Noble Drilling Corporation, a Delaware corporation (the "Company"),
promises to pay to CEDE & CO. or its registered assigns, the principal amount
of _________________________________ MILLION DOLLARS ($__________________) on 
March 15, 2019. This 2019 Note shall not bear interest except as specified on
the other side of this 2019 Note. Additional provisions of this 2019 Note are
set forth on the other side of this Note.

          IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed under its corporate seal.

                                          NOBLE DRILLING CORPORATION



                                          By:
                                             -----------------------------------
                                                Title:


                                      B-1
<PAGE>   24

                    TRUSTEE'S CERTIFICATE OF AUTHENTICATION

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

Dated: March _____, 1999                 CHASE BANK OF TEXAS, NATIONAL
                                         ASSOCIATION, as Trustee


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



                                      B-2
<PAGE>   25

                      [FORM OF REVERSE SIDE OF 2019 NOTE]

                           7.50% SENIOR NOTE DUE 2019

          1. INTEREST. Commencing March 16, 1999, interest on this 2019 Note
will accrue at the rate of 7.50% per annum and will be payable in cash
semiannually on each March 15 and September 15, commencing September 15, 1999,
to 2019 Holders of record on the close of business on the immediately preceding
March 1 and September 1. All such interest shall be payable on demand.

          2. METHOD OF PAYMENT. Subject to the terms and conditions of the
Indenture, payments in respect of the 2019 Notes shall be made at the office or
agency of the Company maintained for that purpose in the City and State of New
York. The Company will pay cash amounts in money of the United States that at
the time of payment is legal tender for payment of public and private debts.

          3. PAYING AGENT AND SECURITY REGISTRAR. Initially, Chase Bank of
Texas, National Association, as Trustee (the "Trustee"), will act as Paying
Agent and Security Registrar. The Company may appoint and change any paying
agent or security registrar without notice, other than notice to the Trustee.
The Company or any of its Subsidiaries or any of their Affiliates may act as
Paying Agent or Security Registrar.

          4. INDENTURE. The Company issued the 2019 Notes under an Indenture,
dated as of March 1, 1999, between the Company and the Trustee, as supplemented
by a First Supplemental Indenture, dated as of March 16, 1999 (collectively,
the "Indenture"). The terms of the 2019 Notes include those stated in the
Indenture and those made part of the Indenture by reference to the Trust
Indenture Act of 1939, as amended (the "Trust Indenture Act of 1939").
Capitalized terms used herein and not defined herein have the meanings ascribed
thereto in the Indenture. The 2019 Notes are subject to all such terms, and
2019 Holders are referred to the Indenture and the Trust Indenture Act of 1939
for a statement of those terms.

          The 2019 Notes are general unsecured obligations of the Company,
limited to $250,000,000 aggregate principal amount.

          5. REDEMPTION AT THE OPTION OF THE COMPANY. No sinking fund is
provided for the 2019 Notes. The 2019 Notes will be subject to redemption at
the option of the Company, in whole or in part, at any time and from time to
time, upon not less than 30 nor more than 60 days' notice, at the Redemption
Price (as defined below).

          If notice of redemption has been given as provided in Article Eleven
of the Indenture and funds for the redemption of any 2019 Notes called for
redemption shall have been made 

                                      B-3
<PAGE>   26

available on the Redemption Date referred to in such notice, such 2019 Notes
will cease to bear interest on the date fixed for such redemption specified in
such notice and the only right of the Holders of the 2019 Notes from and after
the Redemption Date will be to receive payment of the Redemption Price upon
surrender of such 2019 Notes in accordance with such notice.

         As used herein:

         "Make-Whole Premium" with respect to any 2019 Note (or portion of a
2019 Note) to be redeemed shall equal the excess, if any, of:

    (i)  the sum of the present values, calculated as of the Redemption Date, 
of:

              (A) each interest payment that, but for the redemption, would
         have been payable on the 2019 Note (or its portion) being redeemed on
         each Interest Payment Date occurring after the Redemption Date
         (excluding any accrued interest for the period before the Redemption
         Date); and

              (B) the principal amount that, but for the redemption, would have
         been payable at the final maturity of the 2019 Note (or its portion)
         being redeemed;

         over

    (ii) the principal amount of the 2019 Note (or its portion) being redeemed.

         The present values of interest and principal payments referred to in
clause (i) above will be determined in accordance with generally accepted
principles of financial analysis. Those present values will be calculated by
discounting the amount of each payment of interest or principal from the date
that such payment would have been payable, but for the redemption, to the
Redemption Date at a discount rate equal to the Treasury Yield plus 35 basis
points for such 2019 Notes. The Make-Whole Premium will be calculated by an
independent investment banking institution of national standing appointed by
the Company, provided that if the Company fails to make such appointment at
least 45 Business Days prior to the Redemption Date, or if the institution so
appointed is unwilling or unable to make the calculation, such calculation will
be made by the Independent Investment Banker.

         "Redemption Price," with respect to 2019 Notes being redeemed on a
Redemption Date, shall be the price equal to 100% of the principal amount
thereof plus accrued interest to the Redemption Date (subject to the right of
holders of record on the relevant record date to receive interest due on an
Interest Payment Date that is on or prior to the Redemption Date), plus a
Make-Whole Premium, if any is required to be paid. The Redemption Price of any
2019 Notes being 

                                      B-4
<PAGE>   27

redeemed will not ever be less than 100% of the principal
amount of such 2019 Notes plus accrued interest thereon to the Redemption Date.

         If less than all the 2019 Notes are to be redeemed, the particular
2019 Notes or portions thereof to be redeemed shall be selected not more than 60
days prior to the Redemption Date by the Trustee from the Outstanding 2019 Notes
not previously called for redemption, either pro rata, by lot or by another
method the Trustee shall deem fair and reasonable, and the aggregate principal
amounts to be redeemed must be equal to $1,000 or any integral multiple thereof.

          6. DENOMINATIONS; TRANSFER; EXCHANGE. The 2019 Notes are in
registered form, without coupons, in denominations of $1,000 of principal
amount and integral multiples of $1,000. A 2019 Holder may register the
transfer of or exchange 2019 Notes in accordance with the Indenture. The
Security Registrar may require a 2019 Holder, among other things, to furnish
appropriate endorsements and transfer documents and to pay any taxes and fees
required by law or permitted by the Indenture. The Company shall not be
required to exchange or register a transfer of (a) any 2019 Notes for a period
of 15 days next preceding the first mailing or publication of notice of
redemption of 2019 Notes to be redeemed or (b) any 2019 Notes selected, called
or being called for redemption, in whole or in part, except, in the case of any
2019 Note to be redeemed in part, the portion thereof not so to be redeemed.

          7. PERSONS DEEMED OWNERS. The registered Holder of this 2019 Note may
be treated as the owner of this 2019 Note for all purposes.

          8. UNCLAIMED MONEY. The Trustee and each Paying Agent shall each
return to the Company upon written request any money held by them for the
payment of any amount with respect to the 2019 Notes that remains unclaimed for
two years. After return to the Company, 2019 Holders entitled to the money must
look to the Company for payment as general creditors unless an applicable
abandoned property law designates another person.

          9. AMENDMENT; WAIVER. Subject to certain exceptions set forth in the
Indenture, (i) the Indenture or the 2019 Notes may be amended with the written
consent of the Holders of a majority in aggregate principal amount of the 2019
Notes at the time Outstanding and (ii) certain defaults or noncompliance with
certain provisions may be waived with the written consent of the Holders of a
majority in aggregate principal amount of the 2019 Notes at the time
Outstanding. Subject to certain exceptions set forth in the Indenture, without
the consent of any 2019 Holder, the Company and the Trustee may amend the
Indenture or the 2019 Notes to cure any ambiguity, defect or inconsistency, or
to comply with Article Nine of the Indenture, or to make any change that does
not adversely affect the rights of any Holder of 2019 Notes.

          10. DEFAULTS AND REMEDIES. Under the Indenture, Events of Default
include, among others, (a) default in the payment of principal or premium, if
any, when due; (b) default in 




                                      B-5
<PAGE>   28



the payment of any installment of interest when due, continued for 30 days; (c)
default in the performance of any other covenant of the Company applicable to
the 2019 Notes, continued for 90 days after written notice given in accordance
with the Indenture to the Company by the Trustee or to the Company and the
Trustee, by the Holders of at least 25% in aggregate principal amount of the
2019 Notes then Outstanding requiring the same to be remedied; (d) certain
events of bankruptcy, insolvency or reorganization of the Company; and (e)
default under any bond, debenture, note or other evidence of Indebtedness (other
than Non-Recourse Indebtedness) by either of the Company or any Subsidiary or
under any mortgage, indenture or instrument under which there may be issued or
by which there may be secured or evidenced any Indebtedness (other than
Non-Recourse Indebtedness) of either of the Company or any Subsidiary resulting
in the acceleration of such Indebtedness (other than Non-Recourse Indebtedness),
or any default in payment of such Indebtedness (other than Non-Recourse
Indebtedness) (after expiration of any applicable grace periods and presentation
of any debt instruments, if required), if the aggregate amount of all such
Indebtedness (other than Non-Recourse Indebtedness) that has been so accelerated
and with respect to which there has been such a default in payment shall exceed
$25,000,000 and there has been a failure to obtain rescission or annulment of
all such accelerations or to discharge all such defaulted indebtedness within 20
days after there has been given in accordance with the Indenture to the Company
by the Trustee or to the Company and the Trustee by the Holders of at least 25%
in principal amount of the 2019 Notes 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.

          If any Event of Default shall occur and be continuing, the Trustee or
the Holders of not less than 25% in aggregate principal amount of the 2019
Notes then Outstanding, by notice in writing to the Company (and to the
Trustee, if given by the 2019 Holders), may declare the principal of all of the
2019 Notes and the interest, if any, accrued thereon to be due and payable
immediately; provided, however, that the Holders of a majority in aggregate
principal amount of the 2019 Notes then Outstanding, by notice in writing to
the Company and the Trustee, may rescind and annul such declaration and its
consequences if all defaults under such Indenture are cured or waived.

          No Holder of 2019 Notes then Outstanding may institute any suit,
action or proceeding with respect to, or otherwise attempt to enforce, the
Indenture, unless (i) such Holder previously shall have given to the Trustee
written notice of default and of the continuance thereof, (ii) the Holders of
not less than 25% in aggregate principal amount of the 2019 Notes then
Outstanding shall have made written request to the Trustee to institute such
suit, action or proceeding and shall have offered to the Trustee such
reasonable indemnity as it may require with respect thereto and (iii) the
Trustee for 60 days after its receipt of such notice, request and offer of
indemnity, shall have neglected or refused to institute any such action, suit
or proceeding; provided that, the right of any Holder of any 2019 Note to
receive payment of the principal of, premium, if any, or interest, if any, on
such 2019 Note, on or after the respective due dates, or to institute suit for
the enforcement of any such payment shall not be impaired or affected without
the consent of such Holder. The Holders of a majority in aggregate principal
amount of the 2019 Notes then Outstanding may direct 





                                      B-6
<PAGE>   29





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 with
respect to the 2019 Notes, provided that the Trustee may decline to follow such
direction if the Trustee determines that such action or proceeding is unlawful
or would involve the Trustee in personal liability.

          The Company is required to furnish to the Trustee annually a
certificate as to compliance by the Company with all conditions and covenants
under the Indenture.

          11. TRUSTEE DEALINGS WITH THE COMPANY. Subject to certain limitations
imposed by the Trust Indenture Act of 1939 and the Indenture, the Trustee under
the Indenture, in its individual or any other capacity, may become the owner or
pledgee of 2019 Notes and may otherwise deal with and collect obligations owed
to it by the Company or its Affiliates and may otherwise deal with the Company
or its Affiliates with the same rights it would have if it were not Trustee.

          12. NO RECOURSE AGAINST OTHERS. A director, officer, employee or
stockholder, as such, of the Company shall not have any liability for any
obligations of the Company under the 2019 Notes or the Indenture or for any
claim based on, in respect of or by reason of such obligations or their
creation. By accepting a 2019 Note, each 2019 Holder waives and releases all
such liability. The waiver and release are part of the consideration for the
issue of the 2019 Notes.

          13. AUTHENTICATION. This 2019 Note shall not be valid until an
authorized signatory of the Trustee manually signs the Trustee's Certificate of
Authentication on the other side of this 2019 Note.

          14. DEFEASANCE, COVENANT DEFEASANCE. The 2019 Notes are subject to
defeasance and covenant defeasance as provided in the Indenture.

          15. ABBREVIATIONS. Customary abbreviations may be used in the name of
a Holder of 2019 Notes or an assignee, such as TEN COM (= tenants in common),
TEN ENT (= tenants by the entireties), JT TEN (= joint tenants with right of
survivorship and not as tenants in common), CUST (= custodian), and U/G/M/A (=
Uniform Gift to Minors Act).

          16. GOVERNING LAW. THIS 2019 NOTE AND THE INDENTURE SHALL BE GOVERNED
BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK, AS
APPLIED TO CONTRACTS MADE AND PERFORMED WITHIN THE STATE OF NEW YORK, WITHOUT
REGARD TO PRINCIPLES OF CONFLICTS OF LAW.


                                      B-7


<PAGE>   30
          The Company will furnish to any Holder of 2019 Notes upon written
request and without charge a copy of the Indenture. Requests may be made to:
Noble Drilling Corporation, 10370 Richmond Avenue, Suite 400, Houston, Texas
77042, Attention: Corporate Secretary.


                                      B-8
<PAGE>   31

                                   ASSIGNMENT

          FOR VALUE RECEIVED, the undersigned hereby sell(s), assign(s) and
transfer(s) unto ______________________________________________________________
                      (Please insert Name, Social Security Number or other
                                 Identifying Number of Assignee)

at the following address:

_______________________________________________________________________________

_______________________________________________________________________________
    (Please print or typewrite name and address, including postal zip code,
                                  of assignee)

_______________________________________________________________________________

this Note and all rights hereunder, hereby irrevocably constituting and
appointing ____________________________________________________________________
Attorney to transfer this Note on the books of the Trustee, with full power of
substitution in the premises.

Dated: ____________________________     _______________________________________

                                        Notice: The signature(s) on this
                                        Assignment must correspond with the
                                        name(s) as written upon the face of
                                        this Note in every particular, without
                                        alteration or enlargement or any change
                                        whatsoever.


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