ATMOS ENERGY CORP
S-3, 1998-04-20
NATURAL GAS DISTRIBUTION
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<PAGE>   1
 
     AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON APRIL 20, 1998
 
                                               REGISTRATION NO. 333-
================================================================================
 
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
                             ---------------------
                                    FORM S-3
 
                          REGISTRATION STATEMENT UNDER
                           THE SECURITIES ACT OF 1933
                             ---------------------
 
                            ATMOS ENERGY CORPORATION
             (Exact name of Registrant as specified in its charter)
 
<TABLE>
<S>                                            <C>
             TEXAS AND VIRGINIA                                 75-1743247
       (State or other jurisdiction of                       (I.R.S. Employer
       incorporation or organization)                       Identification No.)
          1800 THREE LINCOLN CENTRE                          GLEN A. BLANSCET
              5430 LBJ FREEWAY                        VICE PRESIDENT, GENERAL COUNSEL
             DALLAS, TEXAS 75240                          AND CORPORATE SECRETARY
               (972) 934-9227                            1800 THREE LINCOLN CENTRE
      (Address, including zip code, and                      5430 LBJ FREEWAY
   telephone number, including area code,                   DALLAS, TEXAS 75240
of registrant's principal executive offices)                  (972) 934-9227
                                                    (Name, address, including zip code,
                                                      and telephone number, including
                                                      area code, of agent of service)
</TABLE>
 
                  Please send copies of all communications to:
 
<TABLE>
<S>                                            <C>
               BRYAN E. BISHOP                                JONATHAN JEWETT
                VAN M. JOLAS                               FAITH D. GROSSNICKLE
         LOCKE PURNELL RAIN HARRELL                         SHEARMAN & STERLING
        (A PROFESSIONAL CORPORATION)                       599 LEXINGTON AVENUE
        2200 ROSS AVENUE, SUITE 2200                   NEW YORK, NEW YORK 10022-6069
             DALLAS, TEXAS 75201
               (214) 740-8000
</TABLE>
 
     APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO PUBLIC: From time to
time after the effectiveness of the Registration Statement.
 
     If the only securities being registered on this Form are being offered
pursuant to dividend or interest reinvestment plans, please check the following
box.  [ ]
 
     If any of the securities being registered on this Form are to be offered on
a delayed or continuous basis pursuant to Rule 415 under the Securities Act of
1933, other than the securities offered only in connection with dividend or
interest reinvestment plans, check the following box.  [X]
 
     If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list the Securities Act registration statement number of the earlier
effective registration statement for the same offering.  [ ]
 
     If this Form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering.  [ ]
 
     If delivery of the prospectus is expected to be made pursuant to Rule 434,
please check the following box.  [ ]
 
                        CALCULATION OF REGISTRATION FEE
 
<TABLE>
<CAPTION>
==============================================================================================================================
                                                             PROPOSED MAXIMUM       PROPOSED MAXIMUM
TITLE OF EACH CLASS OF SECURITIES       AMOUNT TO BE          OFFERING PRICE       AGGREGATE OFFERING         AMOUNT OF
        TO BE REGISTERED               REGISTERED(1)          PER UNIT(2)(3)          PRICE(2)(3)          REGISTRATION FEE
- ------------------------------------------------------------------------------------------------------------------------------
<S>                                <C>                    <C>                    <C>                    <C>
Debt Securities............             $150,000,000               100%               $150,000,000             $44,250
==============================================================================================================================
</TABLE>
 
(1) Plus such additional principal amount as may be necessary such that, if Debt
    Securities are issued with an original issue discount, the aggregate initial
    offering price of all Debt Securities will equal $150,000,000.
(2) Estimated solely for purposes of calculating the registration fee.
(3) Excluding accrued interest and accrued amortization of discount, if any, to
the date of delivery.
 
                             ---------------------
 
     THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR
DATES AS MAY BE NECESSARY TO DELAY THEIR EFFECTIVE DATE UNTIL THE REGISTRANT
SHALL FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(A) OF
THE SECURITIES ACT OF 1933, OR UNTIL THE REGISTRATION STATEMENT SHALL BECOME
EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SAID SECTION 8(A),
MAY DETERMINE.
================================================================================
<PAGE>   2
 
INFORMATION CONTAINED HEREIN IS SUBJECT TO COMPLETION OR AMENDMENT. A
REGISTRATION STATEMENT RELATING TO THESE SECURITIES HAS BEEN FILED WITH THE
SECURITIES AND EXCHANGE COMMISSION. THESE SECURITIES MAY NOT BE SOLD NOR MAY
OFFERS TO BUY BE ACCEPTED PRIOR TO THE TIME THE REGISTRATION STATEMENT BECOMES
EFFECTIVE. THIS PROSPECTUS SHALL NOT CONSTITUTE AN OFFER TO SELL OR THE
SOLICITATION OF AN OFFER TO BUY NOR SHALL THERE BE ANY SALE OF THESE SECURITIES
IN ANY STATE IN WHICH SUCH OFFER, SOLICITATION OR SALE WOULD BE UNLAWFUL PRIOR
TO REGISTRATION OR QUALIFICATION UNDER THE SECURITIES LAWS OF ANY SUCH STATE.
 
                  SUBJECT TO COMPLETION, DATED APRIL 20, 1998
 
PROSPECTUS
 
                            ATMOS ENERGY CORPORATION
 
                                  $150,000,000
 
                                DEBT SECURITIES
 
                             ---------------------
 
     Atmos Energy Corporation, a Texas and Virginia corporation (the "Company"),
may offer from time to time, together or separately, its debt securities ("Debt
Securities") on terms to be determined at the time of offering. Debt Securities
with an aggregate issue price of up to $150,000,000 may be issued, in one or
more series, under this Prospectus. The Debt Securities will be unsecured and
will rank equally with all other unsecured and unsubordinated indebtedness of
the Company.
 
     The prospectus supplement ("Prospectus Supplement") accompanying this
Prospectus sets forth, with respect to the particular series or issue of Debt
Securities for which this Prospectus and the Prospectus Supplement are being
delivered ("Offered Securities"): the terms of the Debt Securities offered,
including, where applicable, their title, aggregate principal amount, maturity,
rate of any interest (or the manner of calculation and time of payment thereof),
any redemption or repayment terms, any index, formula or other method pursuant
to which principal, premium or interest may be determined and the form of such
Debt Securities (which may be in registered or global form), any initial public
offering price, the purchase price and net proceeds to the Company and the other
specific terms of such offering.
 
                             ---------------------
 
  THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND
 EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION NOR HAS THE SECURITIES
   AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION PASSED UPON THE
ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A
                               CRIMINAL OFFENSE.
 
                             ---------------------
 
     Offered Securities may be sold directly to purchasers or to or through
underwriters, dealers or agents. If any underwriters, dealers or agents are
involved in the offering of any Offered Securities, their names and any
applicable fee, commission or discount arrangements will be set forth in the
Prospectus Supplement. See "Plan of Distribution".
 
                             ---------------------
 
               The date of this Prospectus is             , 1998.
<PAGE>   3
 
                             AVAILABLE INFORMATION
 
     The Company is subject to the informational requirements of the Securities
Exchange Act of 1934 (the "Exchange Act"), and in accordance therewith files
reports, proxy statements and other information with the Securities and Exchange
Commission (the "Commission"), which may be inspected and copied at the public
reference facilities maintained by the Commission at Judiciary Plaza, Room 1024,
450 Fifth Street, N.W., Room 1024, Washington, D.C. 20549, and at the following
regional offices of the Commission: New York Office (Seven World Trade Center,
Suite 1300, New York, New York 10048) and Chicago Office (500 W. Madison St.,
Suite 1400, Chicago, Illinois 60621-2511). Copies of such materials also can be
obtained upon request from the Public Reference Section of the Commission at
Judiciary Plaza, Room 1024, 450 Fifth Street, N.W., Washington, D.C. 20549, at
prescribed rates. In addition, such materials may also be inspected and copied
at the offices of the New York Stock Exchange, Inc., 20 Broad Street, New York,
New York 10005, on which exchange one or more of the Company's securities are
listed. Finally, copies of reports, proxy statements and other information filed
with the Commission electronically by the Company may be inspected by accessing
the Commission's Internet site at http://www.sec.gov.
 
     The Company has filed with the Commission a registration statement on Form
S-3 (herein, together with all amendments and exhibits, referred to as the
"Registration Statement") under the Securities Act of 1933, as amended (the
"Securities Act"). This Prospectus does not contain all the information set
forth in the Registration Statement, certain parts of which are omitted in
accordance with the rules and regulations of the Commission. For further
information, reference is hereby made to the Registration Statement. Such
additional information may be obtained from the Commission's principal office in
Washington, D.C. Statements contained in this Prospectus as to the contents of
any contract or other document referred to herein or therein are not necessarily
complete, and in each instance reference is made to the copy of such contract or
other document filed as an exhibit to the Registration Statement or such other
document. A copy of the Registration Statement and the exhibits and schedules
thereto may be examined without charge at the Commission's principal offices at
450 Fifth Street, N.W., Room 1024, Washington, D.C. 20549, and copies of such
materials can be obtained from the Public Reference Section of the Commission at
prescribed rates.
 
                INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE
 
     The following documents, which have heretofore been filed by the Company
with the Commission pursuant to the Exchange Act, are incorporated herein by
reference and are deemed to be a part hereof:
 
          (a) Annual Report on Form 10-K for the fiscal year ended September 30,
     1997;
 
          (b) Quarterly Report on Form 10-Q for the quarter ended December 31,
     1997; and
 
          (c) Current Report on Form 8-K dated November 13, 1997.
 
     All documents filed by the Company pursuant to Sections 13(a), 13(c), 14 or
15(d) of the Exchange Act after the date of this Prospectus and prior to the
termination of the offering of the Debt Securities offered hereby also shall be
deemed to be incorporated by reference herein and to be a part hereof from the
date of filing of such documents.
 
     The Company will provide without charge to each person to whom this
Prospectus is delivered, upon the written or oral request of any such person, a
copy of any or all of the foregoing documents incorporated herein by reference,
other than exhibits to such documents (unless such exhibits are specifically
incorporated by reference into such documents). Such requests should be directed
to: Atmos Energy Corporation, 1800 Three Lincoln Centre, 5430 LBJ Freeway,
Dallas, Texas 75240, Attention: Investor Relations.
 
     Any statement contained in a document all or a portion of which is
incorporated or deemed to be incorporated by reference herein shall be deemed to
be modified or superseded for purposes of this Prospectus to the extent that a
statement contained herein or in any other subsequently filed document which
also is or is deemed to be incorporated by reference herein modifies or
supersedes such statement. Any statement so
<PAGE>   4
 
modified shall not be deemed to constitute a part of this Prospectus except as
so modified, and any statement so superseded shall not be deemed to constitute
part of this Prospectus.
 
                DISCLOSURE REGARDING FORWARD-LOOKING STATEMENTS
 
     Statements contained in this Prospectus, including the documents that are
incorporated by reference as set forth in "Incorporation of Certain Documents by
Reference," that are not historical facts are forward-looking statements as
defined in the Private Securities Litigation Reform Act of 1995. Forward-looking
statements are based on management's beliefs as well as assumptions made by and
information currently available to management. Because such statements are based
on expectations as to future economic performance and are not statements of
fact, actual results may differ materially from those projected. Important
factors that could cause future results to differ include, but are not limited
to, national, regional and local economic competitive conditions, regulatory and
business trends and decisions, technological developments, Year 2000 issues,
inflation rates, weather conditions, and other factors discussed in this and
other filings by the Company with the Commission, all of which are difficult to
predict and many of which are beyond the control of the Company. Accordingly,
while the Company believes these forward-looking statements to be reasonable,
there can be no assurance that they will approximate actual experience or that
the expectations derived from them will be realized. When used in the Company's
documents or oral presentations, the words "anticipate," "estimate," "expect,"
"objective," "projection," "forecast," "goal" or similar words are intended to
identify forward-looking statements.
 
                                  THE COMPANY
 
     The Company distributes and sells natural gas and propane to approximately
1.02 million residential, commercial, industrial, agricultural, and other
customers. The Company distributes and sells natural gas through its five
operating divisions to approximately 985,000 customers in 802 cities, towns, and
communities in service areas located in Colorado, Georgia, Illinois, Iowa,
Kansas, Kentucky, Louisiana, Missouri, South Carolina, Tennessee, Texas and
Virginia. The Company also transports gas for others through parts of its
distribution system. It also distributes propane to approximately 29,000
customers in Kentucky, North Carolina, Tennessee and Virginia.
 
     The Company, through various wholly-owned subsidiaries, conducts operations
which complement its natural gas and propane distribution business. One
subsidiary, United Cities Gas Storage Company, owns natural gas storage fields
in Kansas and Kentucky, which are used to supplement natural gas used by
customers in those states. Another subsidiary, UCG Energy Corporation ("UCG
Energy"), leases appliances, real estate, equipment, and vehicles to the United
Cities Gas Company division and others, and owns a small interest in a
partnership engaged in exploration and production activities. UCG Energy also
owns a 45% interest in Woodward Marketing, L.L.C. ("WMLLC"), which conducts a
gas marketing business. WMLLC provides gas marketing services to industrial
customers, municipalities and local distribution companies, including the United
Cities Gas Company division.
 
     UCG Energy also owns Atmos Propane, Inc. (the "Propane Division"), which is
engaged in the retail distribution of propane (LP) gas, the wholesale supply and
transportation of LP gas, the transportation of certain petroleum products for
other companies and the direct merchandising and repair of propane gas
appliances. The Propane Division has LP storage facilities in 15 towns in which
it operates, with a total storage capacity of approximately 2,119,000 gallons.
 
     The Company's principal executive offices are located at 1800 Three Lincoln
Centre, 5430 LBJ Freeway, Dallas, Texas 75240, and its telephone number is (972)
934-9227.
 
                                        2
<PAGE>   5
 
                       RATIO OF EARNINGS TO FIXED CHARGES
 
     The following table sets forth the ratio of earnings to fixed charges for
the Company for the periods indicated:
 
<TABLE>
<CAPTION>
                                                                                THREE MONTHS
                                                                                    ENDED
                                                 YEAR ENDED SEPTEMBER 30,       DECEMBER 31,
                                             --------------------------------   -------------
                                             1993   1994   1995   1996   1997   1996    1997
                                             ----   ----   ----   ----   ----   -----   -----
<S>                                          <C>    <C>    <C>    <C>    <C>    <C>     <C>
Ratio of Earnings to Fixed Charges.........  2.35   2.30   2.31   2.82   1.95   4.00    3.81
</TABLE>
 
     For purposes of computing the foregoing ratios, (i) "earnings" represent
the Company's net income from continuing operations plus applicable income taxes
and fixed charges, and (ii) "fixed charges" represent interest expense,
amortization of debt discount, premium and expense, and a portion of lease
payments considered to represent an interest factor.
 
                                USE OF PROCEEDS
 
     Unless otherwise specified in the applicable Prospectus Supplement, the net
proceeds received by the Company from the sale of the Debt Securities will be
used for the repayment of short-term debt (i) incurred in connection with the
establishment of a new customer service center located in Amarillo, Texas and
(ii) representing transaction costs incurred in connection with the merger of
United Cities Gas Company with and into the Company. If the Company elects at
the time of an issuance of the Debt Securities to make a different or more
specific use of proceeds other than that set forth herein, such use will be
described in the Prospectus Supplement.
 
                         DESCRIPTION OF DEBT SECURITIES
 
     The Debt Securities will be issued under an Indenture ("Indenture") between
the Company and U.S. Bank Trust National Association, Trustee ("Trustee"). The
form of the Indenture has been filed as an exhibit to the Registration
Statement. The Indenture is subject to and governed by the Trust Indenture Act
of 1939, as amended ("TIA"). The following summary of certain provisions of the
Indenture does not purport to be complete and is subject to, and qualified in
its entirety by reference to, the Indenture, including the definitions of
certain terms therein. Whenever particular sections or defined terms of the
Indenture are referred to, such sections or defined terms are incorporated by
reference herein as part of the statement made, and the statement is qualified
in its entirety by such reference.
 
GENERAL
 
     The Indenture provides that any Offered Securities may be issued in one or
more series, in each case as authorized from time to time by the Company; the
Indenture does not limit the aggregate principal amount of debt securities that
may be issued thereunder. Reference is made to the Prospectus Supplement
relating to the Offered Securities for the following:
 
          (1) The title of such Debt Securities.
 
          (2) The aggregate principal amount of such Debt Securities, the
     percentage of their principal amount at which such Debt Securities will be
     issued and the date or dates on which the principal of such Debt Securities
     will be payable or the method by which such date or dates will be
     determined or extended.
 
          (3) The rate or rates (which may be fixed or variable) at which such
     Debt Securities will bear interest, if any, and, if variable, the method by
     which such rate or rates will be determined.
 
          (4) The date or dates from which any interest will accrue or the
     method by which such date or dates will be determined, the date or dates on
     which any interest will be payable (including the Regular
 
                                        3
<PAGE>   6
 
     Record Dates for such Interest Payment Dates) and the basis on which any
     interest will be calculated if other than on the basis of a 360-day year of
     twelve 30-day months.
 
          (5) The place or places, if any, other than or in addition to New York
     City, where the principal of (and premium, if any, on) and interest, if
     any, on such Debt Securities will be payable, where any Debt Securities may
     be surrendered for registration of transfer, where such Debt Securities may
     be surrendered for exchange and where notices or demands to or upon the
     Company in respect of such Debt Securities may be served.
 
          (6) The period or periods within which, the price or prices at which
     and the other terms and conditions upon which, such Debt Securities may be
     redeemed, in whole or in part, at the option of the Company, if the Company
     is to have that option.
 
          (7) The obligation, if any, of the Company to redeem, purchase or
     repay such Debt Securities, in whole or in part, pursuant to any sinking
     fund or analogous provision or at the option of a holder thereof, and the
     period or periods within which, the price or prices at which and the other
     terms and conditions upon which, such Debt Securities will be so redeemed,
     purchased or repaid.
 
          (8) Whether the amount of payments of principal of (and premium, if
     any, on) and interest, if any, on such Debt Securities may be determined
     with reference to an index, formula or other method (which index, formula
     or method may, without limitation, be based on one or more commodities,
     equity indices or other indices) and the manner in which such amounts will
     be determined.
 
          (9) Any deletions from, modifications of or additions to the Events of
     Default or covenants of the Company with respect to such Debt Securities
     (which Events of Default or covenants may not be consistent with the Events
     of Default or covenants set forth in the general provisions of the
     Indenture).
 
          (10) If other than the entire principal amount thereof, the portion of
     the principal amount of such Debt Securities that will be payable upon
     declaration of acceleration of the maturity thereof or the method by which
     such portion will be determined.
 
          (11) Any provisions in modification of, in addition to or in lieu of
     any of the provisions concerning defeasance and covenant defeasance
     contained in the Indenture that will be applicable to such Debt Securities.
 
          (12) Any provisions granting special rights to the holders of such
     Debt Securities upon the occurrence of such events as may be specified.
 
          (13) If other than the Trustee, the designation of any Paying Agent or
     Security Registrar for such Debt Securities, and the designation of any
     transfer or other agents or depositories for such Debt Securities.
 
          (14) Whether such Debt Securities will be issuable initially in
     temporary global form, whether any such Debt Security is to be issuable in
     permanent global form (a "Global Security") and, if so, whether beneficial
     owners of interests in any Global Security may exchange such interests for
     Debt Securities 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 the Indenture, and, if such Debt Securities are
     to be issuable as a Global Security, the identity of the depository for
     such Debt Securities.
 
          (15) The person to whom any interest on any Debt Security will be
     payable, if other than the person in whose name such Debt Security (or one
     or more Predecessor Securities) is registered at the close of business on
     the Regular Record Date for such interest or the manner in which, any
     interest payable on a temporary Debt Security issued in global form will be
     paid (if other than as described in "Book-Entry Debt Securities" below).
 
          (16) The denomination or denominations in which such Debt Securities
     will be issuable, if other than $1,000 or any integral multiple thereof.
 
                                        4
<PAGE>   7
 
          (17) Whether and under what circumstances the Company will pay
     Additional Amounts, as contemplated by Section 1008 of the Indenture, on
     such Debt Securities to any holder who is not a United States person
     (including any modification of the definition of such term as contained in
     the Indenture) in respect of any tax, assessment or governmental charge
     and, if so, whether the Company will have the option to redeem such Debt
     Securities rather than pay such Additional Amounts (and the terms of any
     such option).
 
          (18) Any other, terms, conditions, rights and preferences (or
     limitations on such rights and preferences) of such Debt Securities not
     inconsistent with the provisions of the Indenture (Section 301).
 
     If the terms of any series of Debt Securities provide that the Company may
be required to pay Additional Amounts in respect thereof, for purposes of this
Prospectus, any reference to the payment of the principal of (and premium, if
any, on) or interest, if any, on such Debt Securities will be deemed to include
mention of the payment of the Additional Amounts provided for by the terms of
such Debt Securities.
 
     The Debt Securities referred to on the cover page of this Prospectus, and
any additional debt securities issued under the Indenture, are herein
collectively referred to, while a single Trustee is acting with respect to all
debt securities issued thereunder, as the "Indenture Securities". The Indenture
provides that there may be more than one Trustee thereunder, each with respect
to one or more series of Indenture Securities. At a time when two or more
Trustees are acting under the Indenture, each with respect to only certain
series, the term "Indenture Securities" as used herein will mean the series with
respect to which each respective Trustee is acting. In the event that there is
more than one Trustee under the Indenture, the powers and trust obligations of
each Trustee as described herein will extend only to the series of Indenture
Securities for which it is the Trustee. If two or more Trustees are acting under
the Indenture, then the Indenture Securities for which each Trustee is acting
would in effect be treated as if issued under separate indentures.
 
     The Debt Securities may provide for less than the entire principal amount
thereof to be due and payable upon a declaration of acceleration of the maturity
thereof. A discussion of the federal income tax and other considerations
applicable to Original Issue Discount Securities will be set forth in the
Prospectus Supplement relating thereto.
 
     The Debt Securities will be unsecured obligations of the Company and will
rank on a parity with all other unsecured and unsubordinated indebtedness of the
Company.
 
     The general provisions of the Indenture do not limit the ability of the
Company to incur indebtedness and do not afford holders of Debt Securities
protection in the event of highly leveraged or similar transactions involving
the Company. However, the general provisions of the Indenture do provide that
neither the Company nor any Restricted Subsidiary will subject certain of its
properties or assets to any mortgage or other encumbrance unless the Indenture
Securities outstanding thereunder are secured equally and ratably with or prior
to such other indebtedness thereby secured. See "Limitations on Liens" and
"Limitation on Sale and Leaseback Transactions" under the heading "Certain
Covenants". Reference is made to the Prospectus Supplement for information with
respect to any deletions from, modifications of or additions to the Events of
Default or covenants of the Company that are described below, including any
addition of a covenant or other provision providing event risk or similar
protection.
 
     Under the Indenture, the Company has the ability to issue Indenture
Securities with terms different from those of Indenture Securities previously
issued thereunder and, without the consent of the holders, to reopen a previous
issue of a series of Indenture Securities and issue additional Indenture
Securities of such series (unless such reopening was restricted when such series
was created) in an aggregate principal amount determined by the Company (Section
301).
 
     There is no requirement that future issues of debt securities of the
Company be issued under the Indenture, and the Company will be free to employ
other indentures or documentation, possibly containing provisions different from
those included in the Indenture or applicable to one or more issues of Indenture
Securities, in connection with such future issues.
 
                                        5
<PAGE>   8
 
CERTAIN COVENANTS
 
  Limitations on Liens
 
     The Indenture provides that the Company will not, and will not permit any
Restricted Subsidiary to, create, incur, issue or assume any Indebtedness
secured by any Lien on any Principal Property, or on shares of stock or
Indebtedness of any Restricted Subsidiary ("Restricted Securities"), without
making effective provision for the Outstanding Indenture Securities (other than
any Outstanding Indenture Securities not entitled to this covenant) to be
secured by the Lien equally and ratably with (or prior to) any and all
Indebtedness and obligations secured or to be secured thereby for so long as
such Indebtedness is so secured, except that the foregoing restriction will not
apply to:
 
          (1) Any Lien existing on the date of the first issuance of Indenture
     Securities under the Indenture, including, but not limited to, the Liens on
     property or after-acquired property of the Company or its Subsidiaries
     under the Greeley Indenture or the United Cities Indenture.
 
          (2) Any Lien on any Principal Property or Restricted Securities of any
     Person existing at the time such Person is merged or consolidated with or
     into the Company or a Restricted Subsidiary, or becomes a Restricted
     Subsidiary.
 
          (3) Any Lien on any Principal Property existing at the time of
     acquisition of such Principal Property by the Company or a Restricted
     Subsidiary, whether or not assumed by the Company or such Restricted
     Subsidiary, provided that no such Lien may extend to any other Principal
     Property of the Company or any Restricted Subsidiary.
 
          (4) Any Lien on any Principal Property (including any improvements on
     an existing Principal Property) of the Company or any Restricted
     Subsidiary, and any Lien on the shares of stock of a Restricted Subsidiary
     that was formed or is held for the purpose of acquiring and holding such
     Principal Property, in each case to secure all or any part of the cost of
     acquisition, development, operation, construction, alteration, repair or
     improvement of all or any part of such Principal Property (or to secure
     Indebtedness incurred by the Company or a Restricted Subsidiary for the
     purpose of financing all or any part of such cost); provided that such Lien
     is created prior to, at the time of, or within 12 months after the latest
     of, the acquisition, completion of construction or improvement or
     commencement of commercial operation of such Principal Property and
     provided, further, that no such Lien may extend to any other Principal
     Property of the Company or any Restricted Subsidiary, other than any
     theretofore unimproved real property on which the Principal Property is so
     constructed or developed or the improvement is located.
 
          (5) Any Lien on any Principal Property or Restricted Securities to
     secure Indebtedness owing to the Company or to another Restricted
     Subsidiary.
 
          (6) Any Lien in favor of governmental bodies to secure advances or
     other payments pursuant to any contract or statute or to secure
     Indebtedness incurred to finance the purchase price or cost of constructing
     or improving the property subject to such Lien.
 
          (7) Any Lien created in connection with a project financed with, and
     created to secure, Non-Recourse Indebtedness.
 
          (8) Any Lien required to be placed on any property of the Company or
     its Subsidiaries pursuant to the provisions of the Greeley Indenture, the
     United Cities Indenture, the Note Purchase Agreements or the Loan
     Agreement.
 
          (9) Any extension, renewal, substitution or replacement (or successive
     extensions, renewals, substitutions or replacements), in whole or in part,
     of any Lien referred to in the foregoing clauses (1) through (8), provided
     that the Indebtedness secured thereby may not exceed the principal amount
     of Indebtedness so secured at the time of such renewal or refunding, and
     that such renewal or refunding Lien must be limited to all or any part of
     the same property and improvements thereon, shares of stock or Indebtedness
     that secured the Lien renewed or refunded.
 
                                        6
<PAGE>   9
 
          (10) Any Lien not permitted above securing Indebtedness that, together
     with the aggregate outstanding principal amount of other secured
     Indebtedness that would otherwise be subject to the foregoing restrictions
     (excluding Indebtedness secured by Liens permitted under the foregoing
     exceptions) and the Attributable Debt in respect of all Sale and Leaseback
     Transactions (not including Attributable Debt in respect of any such Sale
     and Leaseback Transactions described in clause (iii) or (iv) of the next
     succeeding paragraph) would not then exceed 10% of Consolidated Net
     Tangible Assets (Section 1006).
 
  Limitation on Sale and Leaseback Transactions
 
     The Indenture provides that the Company will not, and will not permit any
Restricted Subsidiary to, enter into any Sale and Leaseback Transaction unless
(i) the Company or a Restricted Subsidiary would be entitled, without securing
the Outstanding Indenture Securities, to incur Indebtedness secured by a Lien on
the Principal Property that is the subject of such Sale and Leaseback
Transaction; (ii) the Attributable Debt associated therewith would be in an
amount permitted under clause (10) of the preceding paragraph; (iii) the
proceeds received in respect of the Principal Property so sold and leased back
at the time of entering into such Sale and Leaseback Transaction are used for
the business and operations of the Company or any Subsidiary; or (iv) within 12
months after the sale or transfer, an amount equal to the proceeds received in
respect of the Principal Property so sold and leased back at the time of
entering into such Sale and Leaseback Transaction is applied to the prepayment
(other than mandatory prepayment) of any Outstanding Indenture Securities or
Funded Indebtedness of the Company or a Restricted Subsidiary (other than Funded
Indebtedness that is held by the Company or any Restricted Subsidiary or Funded
Indebtedness of the Company that is subordinate in right of payment to any
Outstanding Indenture Securities) (Section 1007).
 
  Certain Definitions
 
     "Attributable Debt" means, as to any particular lease under which any
Person is at the time liable, at any date as of which the amount thereof is to
be determined, the total net amount of rent required to be paid by such Person
under such lease during the remaining term thereof (excluding amounts required
to be paid on account of maintenance and repairs, services, insurance, taxes,
assessments, water rates and similar charges and contingent rents), discounted
from the respective due dates thereof at the weighted average of the rates of
interest (or Yield to Maturity, in the case of Original Issue Discount
Securities) borne by the Indenture Securities then outstanding under the
Indenture, compounded annually.
 
     "Capital Stock" means, with respect to any corporation, any and all shares,
interests, rights to purchase, warrants, options, participations or other
equivalents of or interests (however designated) in stock issued by that
corporation.
 
     "Consolidated Net Tangible Assets" means the aggregate amount of assets
(less applicable reserves and other properly deductible items) after deducting
therefrom (i) all current liabilities (excluding any portion thereof
constituting Funded Indebtedness) and (ii) all goodwill, trade names,
trademarks, patents, unamortized debt discount and expense and other like
intangibles, all as set forth on the most recent consolidated balance sheet of
the Company contained in the latest annual report to shareholders of the Company
and computed in accordance with generally accepted accounting principles.
 
     "Funded Indebtedness" as applied to any Person, means all Indebtedness of
such Person maturing after, or renewable or extendable at the option of such
Person beyond, 12 months from the date of determination.
 
     "Greeley Indenture" means that certain Indenture of Mortgage and Deed of
Trust, dated as of March 1, 1957, from Greeley Gas Company to U.S. Bank National
Association (formerly The Central Bank and Trust Company), as Trustee, as
amended and supplemented through December 1, 1993 (the Indenture of Mortgage and
Deed of Trust through the Tenth Supplemental Indenture by the Company to U.S.
Bank National Association (formerly The Central Bank and Trust Company), as
Trustee).
 
     "Indebtedness" means obligations for money borrowed, evidenced by notes,
bonds, debentures or other similar evidences of indebtedness.
 
                                        7
<PAGE>   10
 
     "Lien" means any lien, mortgage, pledge, encumbrance, charge or security
interest securing Indebtedness; provided, however, that the following types of
transactions will not be considered for purposes of this definition to result in
a Lien: (i) any acquisition by the Company or any Restricted Subsidiary of any
property or assets subject to any reservation or exception under the terms of
which any vendor, lessor or assignor creates, reserves or excepts or has
created, reserved or excepted an interest in oil, gas or any other mineral in
place or the proceeds thereof, (ii) any conveyance or assignment whereby the
Company or any Restricted Subsidiary conveys or assigns to any Person or Persons
an interest in oil, gas or any other mineral in place or the proceeds thereof,
(iii) any Lien upon any property or assets either owned or leased by the Company
or any Restricted Subsidiary or in which the Company or any Restricted
Subsidiary owns an interest that secures for the benefit of the Person or
Persons paying the expenses of developing or conducting operations for the
recovery, storage, transportation or sale of the mineral resources of the such
property or assets (or property or assets with which it is unitized) the payment
to such Person or Persons of the Company's or the Restricted Subsidiary's
proportionate part of such development or operating expenses, (iv) any hedging
arrangements entered into in the ordinary course of business, including any
obligation to deliver any mineral, commodity or asset in connection therewith or
(v) any guarantees by the Company of the repayment of Indebtedness of any
Subsidiary or guarantees by any Subsidiary of the repayment of Indebtedness of
any entity, including, but not limited to, Indebtedness of Woodward Marketing,
L.L.C.
 
     "Loan Agreement" means that certain Loan Agreement by and between the
Company and NationsBank of Texas, N.A., dated as of November 26, 1996.
 
     "Note Purchase Agreements" collectively refers to the following Note
Purchase Agreements, as amended, which were executed by and between the Company
and the following parties on the dates indicated: (i) John Hancock Mutual Life
Insurance Company, dated December 21, 1987; (ii) Mellon Bank, N.A., Trustee
under Master Trust Agreement of AT&T Corporation, dated January 1, 1984, for
Employee Pension Plans -- AT&T -- John Hancock -- Private Placement, dated
December 21, 1987 (Agreement is identical to Hancock Agreement listed above
except as to the parties thereto and the amounts thereof); (iii) John Hancock
Mutual Life Insurance Company, dated October 11, 1989; (iv) The Variable Annuity
Life Insurance Company, dated August 29, 1991; (v) The Variable Annuity Life
Insurance Company, dated August 31, 1992; and (vi) New York Life Insurance
Company, New York Life Insurance and Annuity Corporation, The Variable Annuity
Life Insurance Company, American General Life Insurance Company and Merit Life
Insurance Company, dated November 14, 1994.
 
     "Non-Recourse Indebtedness" means, at any time, Indebtedness incurred after
the date of the Indenture by the Company or a Restricted Subsidiary in
connection with the acquisition of property or assets by the Company or a
Restricted Subsidiary or the financing of the construction of or improvements on
property, whenever acquired, provided that, under the terms of such Indebtedness
and pursuant to applicable law, the recourse at such time and thereafter of the
lenders with respect to such Indebtedness is limited to the property or assets
so acquired, or such construction or improvements, including Indebtedness as to
which a performance or completion guarantee or similar undertaking was initially
applicable to such Indebtedness or the related property or assets if such
guarantee or similar undertaking has been satisfied and is no longer in effect.
 
     "Person" means any individual, corporation, partnership, limited liability
company, joint venture, association, joint-stock company, trust, unincorporated
organization or government or any agency or political subdivision thereof.
 
     "Principal Property" means any natural gas distribution property or propane
property located in the United States, except any such property that in the
opinion of the Board of Directors of the Company is not of material importance
to the total business conducted by the Company and its consolidated
Subsidiaries.
 
     "Restricted Subsidiary" means any Subsidiary that owns or leases a
Principal Property.
 
     "Sale and Leaseback Transaction" means any arrangement with any Person
pursuant to which the Company or any Restricted Subsidiary leases any Principal
Property that has been or is to be sold or transferred by the Company or the
Restricted Subsidiary to such Person, other than (i) a lease for a term,
 
                                        8
<PAGE>   11
 
including renewals at the option of the lessee, of not more than three years or
classified as an operating lease under generally accepted accounting principles,
(ii) leases between the Company and a Restricted Subsidiary or between
Restricted Subsidiaries and (iii) leases of a Principal Property executed by the
time of, or within 12 months after the latest of, the acquisition, the
completion of construction or improvement, or the commencement of commercial
operation, of the Principal Property.
 
     "Subsidiary" of the Company means (i) a corporation, a majority of which
Capital Stock with voting power, under ordinary circumstances, to elect
directors is owned, directly or indirectly, at the date of determination, by the
Company, by one or more Subsidiaries or by the Company and one or more
Subsidiaries or (ii) any other Person (other than a corporation) in which at the
date of determination the Company, one or more Subsidiaries or the Company and
one or more Subsidiaries, directly or indirectly, has at least a majority
ownership and power to direct the policies, management and affairs thereof.
 
     "United Cities Indenture" means that certain Indenture of Mortgage, dated
as of July 15, 1959, from United Cities Gas Company to U.S. Bank Trust National
Association (formerly First Trust of Illinois, National Association), and M.J.
Kruger, as Trustees, as amended and supplemented through July 29, 1997 (the
Indenture of Mortgage through the Twenty-Second Supplemental Indenture by the
Company to U.S. Bank Trust National Association (formerly First Trust National
Association), and Russell C. Bergman, as Trustees) (Section 101).
 
DENOMINATIONS
 
     Unless otherwise provided in the applicable Prospectus Supplement, Debt
Securities are issuable only in fully registered form in denominations of $1,000
and integral multiples of $1,000. The Indenture also provides that Debt
Securities of a series may be issuable in global form. See "Book-Entry Debt
Securities" below (Sections 201, 301 and 302).
 
PAYMENT, TRANSFER AND EXCHANGE
 
     The Company will be required to maintain an office or agency in each Place
of Payment for such series, and may from time to time designate additional
offices or agencies, at which the principal of (and premium, if any, on) and
interest, if any, on such series will be payable (Sections 301 and 1002). If so
provided in the Prospectus Supplement, the Place of Payment will be New York
City, and the Company will initially designate the office of the agent of the
Trustee in New York City as an office where such principal, premium and interest
will be payable. Notwithstanding the foregoing, at the option of the Company,
interest, if any, may be paid on Debt Securities (i) by check mailed to the
person entitled thereto at such person's address appearing in the Security
Register or (ii) by wire transfer to an account located inside the United States
maintained by the person entitled thereto as specified in the Security Register
(Sections 308 and 1002). Unless otherwise provided in the Prospectus Supplement,
payment of any installment of interest on Debt Securities will be made to the
person in whose name such Debt Security is registered at the close of business
on the Regular Record Date for such interest (Section 308).
 
     The Company may from time to time designate additional offices or agencies,
approve a change in the location of any office or agency and, except as provided
above, rescind the designation of any office or agency.
 
     All moneys paid by the Company to the Trustee or a Paying Agent for the
payment of principal of (or premium, if any, on) or interest, if any, on any
Debt Security that remains unclaimed for two years after such principal, premium
or interest becomes due and payable will be repaid to the Company, and the
holder of such Debt Security will (subject to applicable abandoned property or
similar laws) thereafter, as an unsecured general creditor, look only to the
Company for payment thereof (Section 1003).
 
     Subject to the terms of the Indenture and the limitations applicable to
Global Securities, Debt Securities of any series will be exchangeable for other
Debt Securities of the same series of any authorized denominations and of a like
aggregate principal amount (Section 306).
 
     Subject to the terms of the Indenture and the limitations applicable to
Global Securities, Debt Securities of a series may be presented for registration
of transfer and for exchange (i) at each office or agency required to be
maintained by the Company for payment of such series, as described above, and
(ii) at each other office
                                        9
<PAGE>   12
 
or agency that the Company may designate from time to time for such purposes.
Registration of transfers and exchanges will be effected if the transfer agent
is satisfied with the evidence of ownership and identity of the person making
the request and if the transfer form thereon is duly executed. No service charge
will be made for any registration of transfer or exchange of Debt Securities,
but the Company may require payment of any tax or other governmental charge
payable in connection therewith (Section 306).
 
     In the event of any redemption in part, the Company will not be required
(i) to register the transfer of or exchange Debt Securities of any series during
a period beginning at the opening of business 15 days before any selection of
Debt Securities of that series to be redeemed and ending at the close of
business on the date the relevant notice of redemption is mailed, (ii) to
register the transfer of or exchange any Debt Security or portion thereof called
for redemption, except the unredeemed portion, if any, of a Debt Security being
redeemed in part or (iii) to register the transfer of or exchange any Debt
Security that has been surrendered for repayment at the option of the holder,
except the portion, if any, of such Debt Security not to be so repaid (Section
306).
 
CONSOLIDATION, MERGER AND SALE OF ASSETS
 
     The Company may not consolidate with or merge into, or sell, assign,
transfer, lease, convey or otherwise dispose of all or substantially all of its
assets to, any Person, unless each of the following conditions is satisfied:
 
          (1) Immediately after giving effect to such transaction, no Event of
     Default (or event that with notice or lapse of time, or both, would be
     such) with respect to the Indenture Securities will have happened and be
     continuing.
 
          (2) The corporation or other entity formed by such consolidation or
     into which the Company is merged, or the Person to which such properties
     and assets will have been conveyed, transferred or leased, assumes the
     Company's obligation as to the due and punctual payment of the principal of
     (and premium, if any, on) and interest, if any, on the Indenture Securities
     and the performance and observance of every covenant to be performed by the
     Company under the Indenture, and will be organized under the laws of the
     United States, one of the States thereof or the District of Columbia.
 
          (3) The Company has delivered to the Trustee an Officers' Certificate
     and Opinion of Counsel, each stating that the transaction complies with
     these conditions (Section 801).
 
     In the event that any transaction described in and complying with the
conditions listed in the immediately preceding paragraph occurs, the Company
would be discharged from all obligations and covenants under the Indenture and
all obligations under the Indenture Securities, with the successor corporation
or Person succeeding to such obligations and covenants of the Company (Section
802).
 
     In the event of any such transaction, the Indenture provides that, if any
Principal Property or Restricted Securities would thereupon become subject to
any Lien, the Indenture Securities (other than any Indenture Securities not
entitled to the benefit of the "Limitation of Liens" covenant) will be secured,
as to such Principal Property or Restricted Securities, equally and ratably with
(or prior to) the Indebtedness that upon the occurrence of such transaction
would become secured by such Lien, unless such Lien could be created under the
Indenture without equally and ratably securing such Indenture Securities
(Section 803).
 
MODIFICATION AND WAIVER
 
     The Indenture permits the Company and the Trustee, with the consent of the
holders of not less than a majority in aggregate principal amount of Outstanding
Indenture Securities affected thereby, to execute supplemental indentures adding
any provisions to or changing or eliminating any provisions of the Indenture or
modifying the rights of such holders, except that no such supplemental indenture
may, without the consent of the holder of each Outstanding Indenture Security
affected thereby:
 
          (1) Change the Stated Maturity of the principal of (or premium, if
     any, on) or any installment of interest on any Indenture Security, or
     reduce the principal amount thereof (or any premium, if any, thereon) or
     the rate of interest, if any, thereon, or change any obligation of the
     Company to pay
                                       10
<PAGE>   13
 
     Additional Amounts on any Indenture Security as contemplated by Section
     1008 of the Indenture, or reduce the amount of the principal of an Indexed
     Security or an Original Issue Discount Security that would be due and
     payable upon an acceleration of maturity thereof or the amount thereof
     provable in bankruptcy, or adversely affect the right of repayment, if any,
     at the option of the holder, or change any Place of Payment where any
     Indenture Security or any premium or interest thereon is payable, or impair
     the right to institute suit for the enforcement of any such payment on or
     after the Stated Maturity thereof (or on or after any Redemption Date or
     Repayment Date), or adversely affect any right to convert or exchange any
     Indenture Security.
 
          (2) Reduce the aforesaid percentage in principal amount of Outstanding
     Indenture Securities, the consent of the holders of which is required for
     any such supplemental indenture.
 
          (3) Reduce the percentage in principal amount of outstanding Indenture
     Securities, the consent of the holders of which is necessary to modify or
     waive any default under the Indenture (Section 902).
 
     The holders of a majority in aggregate principal amount of Outstanding
Indenture Securities have the right to waive compliance by the Company with
certain covenants contained in the Indenture (Section 1009).
 
     Modification and amendment of the Indenture may be made by the Company and
the Trustee without the consent of any holder, for any of the following
purposes: (i) to evidence the succession of another Person to the Company as
obligor under the Indenture; (ii) to add to the covenants of the Company for the
benefit of the holders of any series of Indenture Securities; (iii) to add
Events of Default for the benefit of the holders of any such series; (iv) to
change or eliminate any provisions of the Indenture, provided that any such
change or elimination will become effective only when there is no Indenture
Security Outstanding thereunder of any series that is entitled to the benefit of
such provisions; (v) to secure the Indenture Securities Outstanding under the
Indenture pursuant to the requirements of Section 803 or 1006 of the Indenture,
or otherwise; (vi) to establish the form or terms of Indenture Securities of any
series, as permitted by Sections 201 and 301 of the Indenture; (vii) to provide
for the acceptance of appointment by a successor Trustee or facilitate the
administration of the trusts under the Indenture by more than one Trustee;
(viii) to close the Indenture with respect to the authentication and delivery of
additional series of Indenture Securities; (ix) to cure any ambiguity or
inconsistency in the Indenture, provided such action does not adversely affect
in any material respect the interests of holders of Indenture Securities of any
series thereunder; (x) to supplement any of the provisions of the Indenture to
the extent necessary to permit or facilitate defeasance and discharge of any
series of Indenture Securities, provided that such action does not adversely
affect in any material respect the interests of the holders of the Indenture
Securities; or (xi) to make any other change that does not affect the rights of
any holder (Section 901).
 
     The Indenture provides that in determining whether the holders of the
requisite principal amount of Indenture Securities of a series then outstanding
have given any request, demand, authorization, direction, notice, consent or
waiver thereunder or whether a quorum is present at a meeting of holders of such
Indenture Securities, (i) the principal amount of an Original Issue Discount
Security that will be deemed to be outstanding will be the amount of the
principal thereof that would be due and payable as of the date of such
determination upon acceleration of the maturity thereof and (ii) the principal
amount of an Indexed Security that may be counted in making such determination
or calculation and that will be deemed outstanding for such purpose will be
equal to the principal face amount of such Indexed Security at original
issuance, unless otherwise provided with respect to such Indenture Security
pursuant to Section 301 (Section 101).
 
EVENTS OF DEFAULT
 
     The following are Events of Default with respect to any series of Indenture
Securities: (i) default in the payment of any installment of interest upon any
Indenture Security of such series when it becomes due and payable, continued for
30 days; (ii) default in the payment of the principal of (or premium, if any,
on) any Indenture Security of such series at its Maturity; (iii) failure on the
part of the Company to observe or perform any other covenant or agreement
contained in the Indenture (other than a covenant or agreement included in the
Indenture solely for the benefit of less than all series of Indenture Securities
or a covenant the
 
                                       11
<PAGE>   14
 
default in the performance of which would be covered by clause (vi) below) for
60 days after written notice of such failure, requiring the Company to remedy
the same, has been given 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
Outstanding Indenture Securities of such series; (iv) default under any
indenture or instrument under which the Company or any Restricted Subsidiary has
at the time outstanding indebtedness for borrowed money or guarantees thereof in
any individual instance in excess of $15,000,000 and, if not already matured in
accordance with its terms, such indebtedness has been accelerated and such
acceleration is not rescinded or annulled within 15 days after notice thereof
has been given 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 Outstanding
Indenture Securities of such series; provided that, if, prior to the entry of
judgment in favor of the Trustee for payment of the Indenture Securities of such
series, the default under such indenture or instrument has been remedied or
cured by the Company or such Restricted Subsidiary, or waived by the holders of
such indebtedness, then the Event of Default under the Indenture will be deemed
likewise to have been remedied, cured or waived; (v) certain events of
bankruptcy, insolvency or reorganization affecting the Company; and (vi) any
other Event of Default included in the Indenture for the benefit of Indenture
Securities of such series (Section 501).
 
     If an Event of Default with respect to Indenture Securities of any series
at the time Outstanding occurs and is continuing, either the Trustee or the
holders of at least 25% in aggregate principal amount of the Outstanding
Securities of that series (or, if the Indenture Securities of that series are
Original Issue Discount Securities or Indexed Securities, such portion of the
principal amount as may be specified in the terms of that series) by notice as
provided in the Indenture may declare the principal amount of all the Indenture
Securities of that series and the accrued interest thereon to be due and payable
immediately. At any time after a declaration of acceleration with respect to
Indenture Securities of any series has been made, but before a judgment or
decree for payment of money has been obtained by the Trustee, the holders of a
majority in aggregate principal amount of the Outstanding Securities of that
series may, under certain circumstances, rescind and annul such acceleration
(Section 502).
 
     The holders of a majority in aggregate principal amount of Outstanding
Indenture Securities of any series have the right to waive certain past defaults
under the Indenture (Section 513).
 
     The Indenture provides that, subject to the duty of the Trustee during
default to act with the required standard of care, the Trustee will be under no
obligation to exercise any of its rights or powers under the Indenture at the
request or direction of any of the holders, unless such holders shall have
offered to the Trustee reasonable indemnity (Section 602). Subject to such
provisions for the indemnification of the Trustee, the holders of a majority in
aggregate principal amount of the Outstanding Securities of any series will 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, with respect to the Indenture Securities of that series unless
the Trustee shall determine that the action specified would be in conflict with
any rule or law (Section 512).
 
     The Company will be required to furnish the Trustee annually a certificate
stating whether or not the Company is in default under the Indenture and, if so,
specifying all such defaults and the nature thereof (Section 1004).
 
DEFEASANCE AND COVENANT DEFEASANCE
 
     The Indenture provides that the Company may elect either (i) to defease and
be discharged from any and all obligations with respect to all or a portion of
the Indenture Securities of any series (except for the obligations (a) to pay
Additional Amounts, if any; (b) to register the transfer of or exchange such
Indenture Securities; (c) to replace temporary or mutilated, destroyed, lost or
stolen Indenture Securities of such series; (d) to maintain an office or agency
in respect of such Indenture Securities; and (e) to hold moneys for payment in
trust) ("defeasance"); or (ii) to be released from its obligations with respect
to such outstanding Indenture Securities under Sections 1006 and 1007 of the
Indenture (being the restrictions described above under "Liens" and "Sale and
Leaseback Transactions", respectively, under the heading "Certain Covenants")
or, if so provided pursuant to the Indenture, its obligations with respect to
any other covenant, and any
 
                                       12
<PAGE>   15
 
omission to comply with such obligations will not constitute a default or an
Event of Default with respect to such Indenture Securities ("covenant
defeasance"), in either case upon the irrevocable deposit by the Company with
the Trustee (or other qualifying trustee), in trust, of (i) an amount in cash
(ii) Government Obligations (as defined below) that, through the payment of
principal and interest in accordance with their terms, will provide money in an
amount, or (iii) a combination thereof in an amount, sufficient to pay the
principal of (and premium, if any, on) and interest, if any, to Stated Maturity
(or redemption) on such Indenture Securities and any mandatory sinking fund or
analogous payments thereon, on the scheduled due dates therefor (Article 14).
 
     Such a trust may only be established if, among other things, the Company
has delivered to the Trustee an Opinion of Counsel to the effect that the
holders of such Indenture Securities will not recognize income, gain or loss for
United States federal income tax purposes as a result of such defeasance or
covenant defeasance and will be subject to United States federal income tax on
the same amounts, in the same manner and at the same times as would have been
the case if such defeasance or covenant defeasance had not occurred, and such
opinion, in the case of defeasance under clause (i) above, must refer to and be
based upon a ruling of the Internal Revenue Service or a change in applicable
United States federal income tax law occurring after the date of the Indenture
(Section 1404).
 
     In the event the Company effects covenant defeasance with respect to any
Indenture Securities and such Indenture Securities are declared due and payable
because of the occurrence of any Event of Default other than (a) an Event of
Default described in clause (iii) under "Events of Default" with respect to
Sections 1006 and 1007 of the Indenture (which Sections would no longer be
applicable to such Indenture Securities) or (b) an Event of Default described in
clause (iii) or (vi) under "Events of Default" with respect to any other
covenant as to which there has been defeasance, the realizable value of the
money and Government Obligations on deposit with the Trustee may not be
sufficient to pay amounts due on such Debt Securities at the time of the
acceleration resulting from such Event of Default, in that the required deposit
with the Trustee is based upon scheduled cash flows rather than market value,
which will vary depending upon interest rates and other factors. However, the
Company would remain liable to make payment of such shortfall amounts due at the
time of acceleration.
 
     The Prospectus Supplement may further describe the provisions, if any,
permitting such defeasance or covenant defeasance, including any modifications
to the provisions described above, with respect to the Indenture Securities of
or within a particular series.
 
BOOK-ENTRY DEBT SECURITIES
 
     Debt Securities of a series may be issued in whole or in part in the form
of one or more Global Securities that will be deposited with, or on behalf of, a
depository identified in the Prospectus Supplement relating to such series.
Global Securities will be issued in registered form and in either temporary or
permanent form. Unless otherwise provided in the Prospectus Supplement, Debt
Securities of a series that are represented by a Global Security may be issued
in any denomination, and will be issued in registered form only, without
coupons. Payments of principal of (and premium, if any, on) and interest, if
any, on Debt Securities of such series represented by a Global Security will be
made by the Company or the Trustee to the depository (Sections 304 and 305).
 
     The Company anticipates that any Global Securities will be deposited with,
or on behalf of, The Depository Trust Company ("DTC"), New York, New York, that
such Global Securities will be registered in the name of DTC's nominee, and that
the following provisions will apply to the depository arrangements with respect
to any such Global Securities. Additional or differing terms of the depository
arrangement will be described in the Prospectus Supplement relating to Offered
Securities issued in the form of Global Securities.
 
     So long as DTC or its nominee is the registered owner of a Global Security,
DTC or its nominee, as the case may be, will be considered the sole holder of
the Debt Securities represented by such Global Security for all purposes under
the Indenture. Except as described below, owners of beneficial interests in a
Global Security will not be entitled to have Debt Securities represented by such
Global Security registered in their names, will not receive or be entitled to
receive physical delivery of Debt Securities in certificated form and
                                       13
<PAGE>   16
 
will not be considered the owners or holders of Debt Securities under the
Indenture. The laws of some states require that certain purchasers of securities
take physical delivery of such securities in certificated form; accordingly,
such laws may limit the transferability of beneficial interests in a Global
Security.
 
     Debt Securities will be issued in fully registered, certificated form
("Definitive Securities") to holders or their nominees, rather than to DTC or
its nominee only if (i) DTC notifies the Trustee in writing that DTC is no
longer willing or able to continue as depositary and a qualified successor
depository is not appointed by the Company within 90 days following such notice;
(ii) the Company, at any time and in its sole discretion, determines not to have
any Debt Securities of one or more series represented by Global Securities; or
(iii) after the occurrence of an Event of Default with respect to such Debt
Securities, a holder of Debt Securities notifies the Trustee in writing that it
wishes to receive a Definitive Security. In any such instance, an owner of a
beneficial interest in a Global Security will be entitled to physical delivery
of Definitive Securities equal in principal amount to such beneficial interest
and registered in its name.
 
     The following is based on information furnished by DTC:
 
          DTC will act as securities depository for the Debt Securities. The
     Debt Securities will be issued as fully registered securities registered in
     the name of Cede & Co. (DTC's nominee). One fully registered Debt Security
     certificate will be issued with respect to each $200 million of principal
     amount of the Debt Securities of a series, and an additional certificate
     will be issued with respect to any remaining principal amount of such
     series.
 
          DTC is a limited-purpose trust company organized under the New York
     Banking Law, a "banking organization" within the meaning of the New York
     Banking Law, a member of the Federal Reserve System, a "clearing
     corporation" within the meaning of the New York Uniform Commercial Code,
     and a "clearing agency" registered pursuant to the provisions of Section
     17A of the Exchange Act. DTC holds securities that its participants
     ("Participants") deposit with DTC.
 
          DTC also facilitates the settlement among Participants of securities
     transactions, such as transfers and pledges, in deposited securities
     through electronic computerized book-entry changes in Participants'
     accounts, thereby eliminating the need for physical movement of securities
     certificates. Direct Participants include securities brokers and dealers,
     banks, trust companies, clearing corporations and certain other
     organizations ("Direct Participants"). DTC is owned by a number of its
     Direct Participants and by the New York Stock Exchange, Inc., the American
     Stock Exchange, Inc. and the National Association of Securities Dealers,
     Inc. Access to the DTC system is also available to others such as
     securities brokers and dealers, banks and trust companies that clear
     through or maintain a custodial relationship with a Direct Participant,
     either directly or indirectly ("Indirect Participants"). The rules
     applicable to DTC and its Participants are on file with the Commission.
 
          Purchases of Debt Securities under the DTC system must be made by or
     through Direct Participants, which will receive a credit for the Debt
     Securities on DTC's records. The ownership interest of each actual
     purchaser of each Debt Security ("Beneficial Owner") is in turn to be
     recorded on the Participants' records. A Beneficial Owner will not receive
     written confirmation from DTC of its purchase, but such Beneficial Owner is
     expected to receive a written confirmation providing details of the
     transaction, as well as periodic statements of its holdings, from the
     Participant through which such Beneficial Owner entered into the
     transaction. Transfers of ownership interests in Debt Securities are to be
     accomplished by entries made on the books of Participants acting on behalf
     of Beneficial Owners. Beneficial Owners will not receive certificates
     representing their ownership interests in Debt Securities, except in the
     event that use of the book-entry system for the Debt Securities is
     discontinued.
 
          To facilitate subsequent transfers, the Debt Securities will be
     registered in the name of DTC's partnership nominee, Cede & Co. The deposit
     of the Debt Securities with DTC and their registration in the name of Cede
     & Co. will effect no change in beneficial ownership. DTC will have no
     knowledge of the actual Beneficial Owners of the Debt Securities; DTC
     records will reflect only the identity of the Direct Participants to whose
     accounts Debt Securities are credited, which may or may not be the
 
                                       14
<PAGE>   17
 
     Beneficial Owners. The Participants will remain responsible for keeping
     account of their holdings on behalf of their customers.
 
          Delivery of notices and other communications by DTC to Direct
     Participants, by Direct Participants to Indirect Participants, and by
     Direct and Indirect Participants to Beneficial Owners will be governed by
     arrangements among them, subject to any statutory or regulatory
     requirements as may be in effect from time to time.
 
          Neither DTC nor Cede & Co. will consent or vote with respect to the
     Debt Securities. Under its usual procedures, DTC mails a proxy (an "Omnibus
     Proxy") to the issuer as soon as possible after the record date. The
     Omnibus Proxy assigns Cede & Co.'s consenting or voting rights to those
     Direct Participants to whose accounts the Debt Securities are credited on
     the record date (identified on a list attached to the Omnibus Proxy).
 
          Principal, premium and interest payments on the Debt Securities will
     be made to DTC. DTC's practice is to credit Direct Participants' accounts
     on the payment date in accordance with their respective holdings as shown
     on DTC's records unless DTC has reason to believe that it will not receive
     payment on the payable date. Payments by Participants to Beneficial Owners
     will be governed by standing instructions and customary practices, as is
     the case with securities held for the accounts of customers in bearer form
     or registered in "street name", and will be the responsibility of such
     Participant and not of DTC, the Paying Agent or the Company, subject to any
     statutory or regulatory requirements as may be in effect from time to time.
     Payment of principal and interest to DTC is the responsibility of the
     Company or the Paying Agent, disbursement of such payments to Direct
     Participants will be the responsibility of DTC, and disbursement of such
     payments to the Beneficial Owners will be the responsibility of Direct and
     Indirect Participants.
 
          DTC may discontinue providing its services as securities depository
     with respect to the Debt Securities at any time by giving reasonable notice
     to the Company or the Paying Agent. Under such circumstances, in the event
     that a successor securities depository is not appointed, Debt Security
     certificates are required to be printed and delivered.
 
          The Company may decide to discontinue use of the system of book-entry
     transfers through DTC (or a successor securities depository). In that
     event, Debt Security certificates will be printed and delivered.
 
     The information in this section concerning DTC and DTC's book-entry system
has been obtained from sources (including DTC) that the Company believes to be
reliable, but the Company takes no responsibility for the accuracy thereof.
 
     Unless stated otherwise in the applicable Prospectus Supplement, the
underwriters or agents with respect to Offered Debt Securities issued as Global
Securities will be Direct Participants in DTC.
 
     None of the Company, any underwriter or agent, the Trustee or any Paying
Agent will have any responsibility or liability for any aspect of the records
relating to or payments made on account of beneficial interests in a Global
Security, or for maintaining, supervising or reviewing any records relating to
such beneficial interests.
 
CONCERNING THE TRUSTEE
 
     U.S. Bank Trust National Association is the Trustee under the Indenture.
The Trustee serves as trustee under (i) the Twenty-First Supplemental Indenture,
dated as of February 5, 1997, and the Twenty-Second Supplemental Indenture,
dated as of July 29, 1997, supplementing an Indenture of Mortgage, dated as of
July 15, 1959, relating to the Company's First Mortgage Bonds aggregating $111
million, and (ii) the Company's Medium Term Notes, Series A aggregating $22
million.
 
                                       15
<PAGE>   18
 
                              PLAN OF DISTRIBUTION
 
     The Company may sell the Offered Securities to one or more underwriters for
public offering and sale by them or may sell the Offered Securities to investors
directly or through agents. Any such underwriter or agent involved in the offer
and sale of the Offered Securities will be named in the related Prospectus
Supplement. The Company has reserved the right to sell the Offered Securities
directly to investors on its own behalf in those jurisdictions where it is
authorized to do so.
 
     Underwriters may offer and sell the Offered Securities at a fixed price or
prices that may be changed, at market prices prevailing at the time of sale, at
prices related to such prevailing market prices or at negotiated prices. The
Company also may, from time to time, authorize dealers, acting as the Company's
agents, to offer and sell the Offered Securities upon such terms and conditions
as set forth in the related Prospectus Supplement. In connection with the sale
of the Offered Securities, underwriters may receive compensation from the
Company in the form of underwriting discounts or commissions and may also
receive commissions from purchasers of the Offered Securities for whom they may
act as agent. Underwriters may sell the Offered Securities to or through
dealers, and such dealers may receive compensation in the form of discounts,
concessions or commissions from the underwriters and/or commissions (which may
be changed from time to time) from the purchaser for whom they may act as
agents.
 
     Any underwriting compensation paid by the Company to underwriters or agents
in connection with the offering of the Offered Securities, and any discounts,
concessions or commissions allowed by underwriters to participating dealers,
will be set forth in the related Prospectus Supplement. Dealers and agents
participating in the distribution of the Offered Securities may be deemed to be
underwriters, and any discounts and commissions received by them and any profit
realized by them on resale of the Offered Securities may be deemed to be
underwriting discounts and commissions under the Securities Act. Underwriters,
dealers and agents may be entitled, under agreements entered into with the
Company, to indemnification against and contribution towards certain civil
liabilities, including any liabilities under the Securities Act.
 
     Until the distribution of the Offered Securities is completed, rules of the
Commission may limit the ability of underwriters to bid for and purchase the
Offered Securities. As an exception to these rules, underwriters are permitted
to engaged in certain transactions that stabilize the price of the Offered
Securities. Such transactions consist of bids or purchases for the purpose of
pegging, fixing or maintaining the price of the Offered Securities. If
underwriters create a short position in the Offered Securities in connection
with the offering, i.e., if they sell more Offered Securities than are set forth
on the cover page of the applicable Prospectus Supplement, underwriters may
reduce that short position by purchasing Offered Securities in the open market.
In general, purchase of a security for the purpose of stabilization or to reduce
a short position could cause the price of the security to be higher than it
might be in the absence of such purchases. Such activities, if commenced, may be
discontinued at any time.
 
     If so indicated in the related Prospectus Supplement, the Company will
authorize underwriters, dealers or agents to solicit offers by certain
institutions to purchase such Offered Securities from the Company pursuant to
delayed delivery contracts providing for payment and delivery at a future date.
Such contracts will be subject only to those conditions set forth in the related
Prospectus Supplement, and the Prospectus Supplement will set forth the
commission payable for solicitation of such contracts.
 
     Any Offered Securities issued hereunder will be new issues of securities
with no established trading market. Any underwriters or agents to or through
whom such Offered Securities are sold by the Company for public offering and
sale may make a market in such Offered Securities, but such underwriters or
agents will not be obligated to do so and may discontinue any market at any time
without notice. No assurance can be given as to the liquidity of the trading
market for any such Offered Securities.
 
     Certain of the underwriters, dealers or agents and their associates may
engage in transactions with, and perform services for, the Company and certain
of its affiliates in the ordinary course of business.
 
                                       16
<PAGE>   19
 
                                 LEGAL MATTERS
 
     Certain legal matters relating to the Debt Securities will be passed upon
for the Company by Locke Purnell Rain Harrell (A Professional Corporation), in
Dallas Texas. Dan Busbee, a director of the Company, is a shareholder in such
law firm. The validity of the Offered Securities will be passed upon for any
underwriters, dealers or agents by Shearman & Sterling, New York, New York.
 
                                    EXPERTS
 
     The consolidated financial statements of the Company at September 30, 1997
appearing in the Company's Annual Report on Form 10-K have been audited by Ernst
& Young LLP, independent auditors, as set forth in its report included therein
and incorporated herein by reference. Such consolidated financial statements are
incorporated herein by reference in reliance upon such report given upon the
authority of such firm as experts in accounting and auditing.
 
     The consolidated financial statements of United Cities Gas Company at
December 31, 1996 appearing in the Company's Annual Report on Form 10-K have
been audited by Arthur Andersen LLP, independent auditors, as set forth in its
report included therein and incorporated herein by reference. Such consolidated
financial statements are incorporated herein by reference in reliance upon such
report given upon the authority of such firm as experts in accounting and
auditing.
 
                                       17
<PAGE>   20
 
                                    PART II
 
                     INFORMATION NOT REQUIRED IN PROSPECTUS
 
ITEM 14. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION.
 
     The following table indicates the expenses to be paid by the Registrant in
connection with the sale and distribution of the Debt Securities being
registered hereby, other than underwriting or broker dealer fees, discounts and
commissions. All amounts are estimated except for the Securities Act
registration fee.
 
<TABLE>
<S>                                                           <C>
Securities and Exchange Commission registration fee.........  $ 44,250
Rating agency fees..........................................    86,250
Trustee's fees and expenses.................................     5,000
Blue Sky fees (including counsel fees)......................     2,500
Accounting fees and expenses................................    30,000
Legal fees and expenses.....................................    40,000
Printing expenses...........................................    12,000
Miscellaneous expenses......................................    20,000
                                                              --------
          Total.............................................  $240,000
                                                              ========
</TABLE>
 
ITEM 15. INDEMNIFICATION OF DIRECTORS AND OFFICERS.
 
     The Texas Business Corporation Act and the Virginia Stock Corporation Act
permit, and in some cases require, corporations to indemnify directors and
officers who are or have been a party or are threatened to be made a party to
litigation against judgments, penalties (including excise and similar taxes),
fines, settlements, and reasonable expenses under certain circumstances. Article
IX of the Company's Restated Articles of Incorporation, as Amended, and Article
IX of the Company Bylaws provide for indemnification of judgments, penalties
(including excise and similar taxes), fines, settlements, and reasonable
expenses and the advance payment or reimbursement of such reasonable expenses to
directors and officers to the fullest extent permitted by law.
 
     As authorized by Article 2.02-1 of the Texas Business Corporation Act (the
"TBCA"), and Section 13.1-697 of the Virginia Stock Corporation Act ("VSCA"),
each director and officer of the Company may be indemnified by the Company
against expenses (including attorney's fees, judgments, fines and amounts paid
in settlement) actually and reasonably incurred in connection with the defense
or settlement of any threatened, pending or completed legal proceedings in which
he is involved by reason of the fact that he is or was a director or officer of
the Company if he acted in good faith and in a manner that he reasonably
believed to be in or not opposed to the best interests of the Company, and, with
respect to any criminal action or proceeding, if he had no reasonable cause to
believe that his conduct was unlawful. In each case, such indemnity shall be to
the fullest extent authorized by the TBCA and the VSCA, as amended. If the
director or officer is found liable for willful or intentional misconduct in the
performance of his duty to the Company, then indemnification will not be made.
 
     Article X of the Restated Articles of Incorporation, as Amended, of the
Company provides that no director of the Company shall be personally liable to
the Company or its shareholders for monetary damages for any breach of fiduciary
duty as a director except for liability (i) for any breach of duty of loyalty to
the Company or its shareholders, (ii) for an act or omission not in good faith
or which involves intentional misconduct or a knowing violation of law, (iii)
for a transaction from which the director received an improper benefit, whether
or not the benefit resulted from an action taken within the scope of the
director's office, (iv) for an act or omission for which the liability of a
director is expressly provided by statute or (v) for an act related to an
unlawful stock repurchase or payment of a dividend. In addition, Article IX of
the Restated Articles of Incorporation, as Amended, and Article IX of the
Amended and Restated Bylaws of the Company require the Company to indemnify to
the fullest extent authorized by law any person made or threatened to be made
party to any action, suit or proceeding, whether criminal, civil,
administrative, arbitrative or investigative, by reason of the fact that such
person is or was a director or officer of the Company or serves or served at
 
                                      II-1
<PAGE>   21
 
the request of the Company as a director, officer, partner, venturer,
proprietor, trustee, employee, agent or similar functionary of any other
enterprise.
 
     The Company maintains an officers' and directors' liability insurance
policy insuring officers and directors against certain liabilities, including
liabilities under the Securities Act of 1933. The effect of such policy is to
indemnify such officers and directors of the Company against losses incurred by
them while acting in such capacities.
 
     Insofar as indemnification for liabilities arising under the Securities Act
may be permitted to directors, officers or persons controlling the Company,
pursuant to the foregoing provisions, the Company has been informed that in the
opinion of the Commission such indemnification is against public policy as
expressed in such act and is therefore unenforceable.
 
ITEM 16. EXHIBITS.
 
<TABLE>
<C>                      <C>  <S>
         1.1              --  Form of Purchase Agreement.*
         4.1              --  Form of Indenture.
         4.2              --  Form of Debt Security.*
         4.3(a)           --  Note Purchase Agreement, dated as of December 21, 1987, by
                              and between the Company and John Hancock Mutual Life
                              Insurance Company (Exhibit 10(c) of Form 8-K filed January
                              7, 1988 (File No. 0-11249)).
                              Note Purchase Agreement, dated as of December 21, 1987, by
                              and between the Company and John Hancock Charitable Trust I
                              (Agreement is identical to Hancock Agreement listed above
                              except as to the parties thereto and the amounts thereof.).
                              Note Purchase Agreement dated as of December 21, 1987, by
                              and between the Company and Mellon Bank, N.A., Trustee under
                              Master Trust Agreement of AT&T Corporation, dated January 1,
                              1984, for Employee Pension Plans -- AT&T -- John
                              Hancock -- Private Placement (Agreement is identical to
                              Hancock Agreement listed above except as to the parties
                              thereto and the amounts thereof.).
         4.3(b)           --  Amendment to Note Purchase Agreement, dated October 11,
                              1989, by and between the Company and John Hancock Mutual
                              Life Insurance Company revising Note Purchase Agreement
                              dated December 21, 1987 (Exhibit (10(b)(ii) of Form 10-K for
                              fiscal year ended September 30, 1989 (File No. 1-10042)).
                              Amendment to Note Purchase Agreement, dated October 11,
                              1989, by and between the Company and John Hancock Charitable
                              Trust I revising Note Purchase Agreement dated December 21,
                              1987 (Amendment is identical to Hancock amendment listed
                              above except as to the parties thereto and the amounts
                              thereof.).
                              Amendment to Note Purchase Agreement dated October 11, 1989,
                              by and between the Company and Mellon Bank, N.A., Trustee
                              under Master Trust Agreement of AT&T Corporation, dated
                              January 1, 1984, for Employee Pension Plans -- AT&T -- John
                              Hancock -- Private Placement revising Note Purchase
                              Agreement dated December 21, 1987 (Amendment is identical to
                              Hancock amendment listed above except as to the parties
                              thereto and the amounts thereof.).
         4.3(c)           --  Amendment to Note Purchase Agreement dated November 12,
                              1991, by and between the Company and John Hancock Mutual
                              Life Insurance Company revising Note Purchase Agreement
                              dated December 21, 1987 (Exhibit 10(b)(iii) of Form 10-K for
                              fiscal year ended September 30, 1991 (File No. 1-10042)).
</TABLE>
 
                                      II-2
<PAGE>   22
<TABLE>
<C>                      <C>  <S>
                              Amendment to Note Purchase Agreement, dated November 12,
                              1991, by and between the Company and John Hancock Charitable
                              Trust I revising Note Purchase Agreement dated December 21,
                              1987 (Amendment is identical to Hancock amendment listed
                              above except as to the parties thereto and the amounts
                              thereof.).
                              Amendment to Note Purchase Agreement, dated November 12,
                              1991, by and between the Company and Mellon Bank, N.A.,
                              Trustee under Master Trust Agreement of AT&T Corporation,
                              dated January 1, 1984, for Employee Pension
                              Plans -- AT&T -- John Hancock -- Private Placement revising
                              Note Purchase Agreement dated December 21, 1987 (Amendment
                              is identical to Hancock amendment above except as to the
                              parties thereto and the amounts thereof.).
         4.3(d)           --  Amendment to Note Purchase Agreement, dated December 22,
                              1993, by and between the Company and John Hancock Mutual
                              Life Insurance Company revising Note Purchase Agreement
                              dated December 21, 1987.
                              Amendment to Note Purchase Agreement, dated December 22,
                              1993, by and between the Company and Mellon Bank, N.A.,
                              Trustee under Master Trust Agreement of AT&T Corporation,
                              dated January 1, 1984, for Employee Pension
                              Plans -- AT&T -- John Hancock -- Private Placement revising
                              Note Purchase Agreement dated December 21, 1987 (Amendment
                              is identical to Hancock amendment listed above except as to
                              the parties thereto and the amounts thereof).
         4.3(e)           --  Amendment to Note Purchase Agreement, dated December 20,
                              1994 by and between the Company and John Hancock Mutual Life
                              Insurance Company revising Note Purchase Agreement dated
                              December 21, 1987.
                              Amendment to Note Purchase Agreement, dated December 20,
                              1994, by and between the Company and Mellon Bank, N.A.,
                              Trustee under Master Trust Agreement of AT&T Corporation,
                              dated January 1, 1984, for Employee Pension
                              Plans -- AT&T -- John Hancock -- Private Placement revising
                              Note Purchase Agreement dated December 21, 1987 (Amendment
                              is identical to Hancock amendment listed above).
         4.3(f)           --  Amendment to Note Purchase Agreement, dated July 29, 1997,
                              by and between the Company and John Hancock Mutual Life
                              Insurance Company revising Note Purchase Agreement dated
                              December 21, 1987.
                              Amendment to Note Purchase Agreement, dated July 29, 1997,
                              by and between the Company and Mellon Bank, N.A., Trustee
                              under Master Trust Agreement of AT&T Corporation, dated
                              January 1, 1984, for Employee Pension Plans -- AT&T -- John
                              Hancock -- Private Placement revising Note Purchase
                              Agreement dated December 21, 1987 (Amendment is identical to
                              Hancock Amendment listed above except as to the parties
                              thereto and the amounts thereof).
         4.4(a)           --  Note Purchase Agreement, dated as of October 11, 1989, by
                              and between the Company and John Hancock Mutual Life
                              Insurance Company (Exhibit 10(c) of Form 10-K for fiscal
                              year ended September 30, 1989 (File No. 1-10042)).
         4.4(b)           --  Amendment to Note Purchase Agreement, dated as of November
                              12, 1991, by and between the Company and John Hancock Mutual
                              Life Insurance Company revising Note Purchase Agreement
                              dated October 11, 1989 (Exhibit 10(c)(ii) of Form 10-K for
                              fiscal year ended September 30, 1991 (File No. 1-10042)).
         4.4(c)           --  Amendment to Note Purchase Agreement, dated December 22,
                              1993, by and between the Company and John Hancock Mutual
                              Life Insurance Company revising Note Purchase Agreement
                              dated October 11, 1989.
</TABLE>
 
                                      II-3
<PAGE>   23
<TABLE>
<C>                      <C>  <S>
         4.4(d)           --  Amendment to Note Purchase Agreement, dated December 20,
                              1994, by and between the Company and John Hancock Mutual
                              Life Insurance Company revising Note Purchase Agreement
                              dated October 11, 1989.
         4.4(e)           --  Amendment to Note Purchase Agreement, dated July 29, 1997,
                              by and between the Company and John Hancock Mutual Life
                              Insurance Company revising Note Purchase Agreement dated
                              October 11, 1989.
         4.5(a)           --  Note Purchase Agreement, dated as of August 29, 1991, by and
                              between the Company and The Variable Annuity Life Insurance
                              Company (Exhibit 10(f)(i) of Form 10-K for fiscal year ended
                              September 30, 1991 (File No. 10042)).
         4.5(b)           --  Amendment to Note Purchase Agreement, dated November 26,
                              1991, by and between the Company and The Variable Annuity
                              Life Insurance Company revising Note Purchase Agreement
                              dated August 29, 1991 (Exhibit 10(f)(ii) of Form 10-K for
                              fiscal year ended September 30, 1991 (File No. 1-10042)).
         4.5(c)           --  Amendment to Note Purchase Agreement, dated December 22,
                              1993, by and between the Company and The Variable Annuity
                              Life Insurance Company revising Note Purchase Agreement
                              dated August 29, 1991.
         4.5(d)           --  Amendment to Note Purchase Agreement, dated July 29, 1997,
                              by and between the Company and The Variable Annuity Life
                              Insurance Company revising Note Purchase Agreement dated
                              August 29, 1991.
         4.6(a)           --  Note Purchase Agreement, dated as of August 31, 1992, by and
                              between the Company and The Variable Annuity Life Insurance
                              Company (Exhibit 10(f) of Form 10-K for fiscal year ended
                              September 30, 1992 (File No. 1-10042)).
         4.6(b)           --  Amendment to Note Purchase Agreement, dated December 22,
                              1993, by and between the Company and The Variable Annuity
                              Life Insurance Company revising Note Purchase Agreement
                              dated August 31, 1992.
         4.6(c)           --  Amendment to Note Purchase Agreement, dated July 29, 1997,
                              by and between the Company and The Variable Annuity Life
                              Insurance Company revising Note Purchase Agreement dated
                              August 31, 1992.
         4.7(a)           --  Note Purchase Agreement, dated November 14, 1994, by and
                              among the Company and New York Life Insurance Company, New
                              York Life Insurance and Annuity Corporation, The Variable
                              Annuity Life Insurance Company, American General Life
                              Insurance Company, and Merit Life Insurance Company (Exhibit
                              10.1 of Form 10-Q for quarter ended December 31, 1994 (File
                              No. 1-10042)).
         4.7(b)           --  Amendment to Note Purchase Agreement, dated July 29, 1997,
                              by and among the Company and New York Life Insurance
                              Company, New York Life Insurance and Annuity Corporation,
                              The Variable Annuity Life Insurance Company, American
                              General Life Insurance Company and Merit Life Insurance
                              Company revising Note Purchase Agreement dated November 14,
                              1994.
         4.8              --  Loan Agreement by and between the Company and NationsBank of
                              Texas, N.A. dated as of November 26, 1996 (Exhibit 10.1 of
                              Form 10-Q for quarter ended December 31, 1996 (File No.
                              1-10042)).
         4.9(a)           --  Indenture of Mortgage, dated as of July 15, 1959, from
                              United Cities Gas Company to First Trust of Illinois,
                              National Association, and M.J. Kruger, as Trustees, as
                              amended and supplemented through December 1, 1992 (the
                              Indenture of Mortgage through the 20th Supplemental
                              Indenture) (Exhibit to Registration Statement of United
                              Cities Gas Company on Form S-3 (File No. 33-56983)).
</TABLE>
 
                                      II-4
<PAGE>   24
<TABLE>
<C>                      <C>  <S>
         4.9(b)           --  Twenty-First Supplemental Indenture dated as of February 5,
                              1997 by and among United Cities Gas Company and Bank of
                              America Illinois and First Trust National Association and
                              Russell C. Bergman supplementing Indenture of Mortgage dated
                              as of July 15, 1959 (Exhibit 10.7(a) of Form 10-K for the
                              fiscal year ended September 30, 1997 (File No. 1-10042)).
         4.9(c)           --  Twenty-Second Supplemental Indenture dated as of July 29,
                              1997 by and among the Company and First Trust National
                              Association and Russell C. Bergman supplementing Indenture
                              of Mortgage dated as of July 15, 1959 (Exhibit 10.7(b) of
                              Form 10-K for the fiscal year ended September 30, 1997 (File
                              No. 1-10042)).
         4.10(a)          --  Form of Indenture between United Cities Gas Company and
                              First Trust of Illinois, National Association, as Trustee
                              dated as of November 15, 1995 (Exhibit to Registration
                              Statement of United Cities Gas Company on Form S-3 (File No.
                              33-56983)).
         4.10(b)          --  First Supplemental Indenture between the Company and First
                              Trust of Illinois, National Association, as Trustee dated as
                              of July 29, 1997 (Exhibit 10.8(a) of Form 10-K for the
                              fiscal year ended September 30, 1997 (File No. 1-10042)).
         4.11(a)          --  Seventh Supplemental Indenture, dated as of October 1, 1983
                              between Greeley Gas Company ("the Greeley Gas Division") and
                              the Central Bank of Denver, N.A. ("Central Bank") (Exhibit
                              10.1 of Form 10-Q for quarter ended June 30, 1994 (File No.
                              1-10042)).
         4.11(b)          --  Ninth Supplemental Indenture, dated as of April 1, 1991,
                              between the Greeley Gas Division and Central Bank (Exhibit
                              10.2 of Form 10-Q for quarter ended June 30, 1994 (File No.
                              1-10042)).
         4.11(c)          --  Bond Purchase Agreement, dated as of April 1, 1991, between
                              the Greeley Gas Division and Central Bank (Exhibit 10.3 of
                              Form 10-Q for quarter ended June 30, 1994 (File No.
                              1-10042)).
         4.11(d)          --  Tenth Supplemental Indenture, dated as of December 1, 1993,
                              between the Company and Colorado National Bank, formerly
                              Central Bank (Exhibit 10.4 of Form 10-Q for quarter ended
                              June 30, 1994 (File No. 1-10042)).
         5.1              --  Opinion of Locke Purnell Rain Harrell (A Professional
                              Corporation) as to certain legal matters.
        12.1              --  Computation of Ratio of Earnings to Fixed Charges of the
                              Company.
        23.1              --  Consent of Ernst & Young LLP.
        23.2              --  Consent of Arthur Andersen LLP.
        23.3              --  Consent of Locke Purnell Rain Harrell (A Professional
                              Corporation) (set forth in its opinion filed as Exhibit
                              5.1).
        24.1              --  Powers of attorney (set forth on the signature page(s)
                              hereof).
        25.1              --  Statement of Eligibility and Qualifications on Form T-1 of
                              Trustee under the Indenture.
</TABLE>
 
- ---------------
 
* Such exhibit will be filed by the Registrant as an exhibit to a Current Report
  on Form 8-K and incorporated herein by reference.
 
                                      II-5
<PAGE>   25
 
ITEM 17. UNDERTAKINGS.
 
     (a) RULE 415 OFFERING. The undersigned registrant hereby undertakes:
 
          (1) To file, during any period in which offers or sales are being
     made, a post-effective amendment to this registration statement:
 
             (i) To include any prospectus required by section 10(a)(3) of the
        Securities Act of 1933;
 
             (ii) To reflect in the prospectus any facts or events arising after
        the effective date of the registration statement (or the most recent
        post-effective amendment thereof) which, individually or in the
        aggregate, represent a fundamental change in the information set forth
        in the registration statement. Notwithstanding the foregoing, any
        increase or decrease in volume of securities offered (if the total
        dollar value of securities offered would not exceed that which was
        registered) and any deviation from the low or high and of the estimated
        maximum offering range may be reflected in the form of prospectus filed
        with the Commission pursuant to Rule 424(b) if, in the aggregate, the
        changes in volume and price represent no more than a 20% change in the
        maximum aggregate offering price set forth in the "Calculation of
        Registration Fee" table in the effective registration statement;
 
             (iii) To include any material information with respect to the plan
        of distribution not previously disclosed in the registration statement
        or any material change to such information in the registration
        statement;
 
          Provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) of this
     section do not apply if the information required to be included in a
     post-effective amendment by those paragraphs is contained in periodic
     reports filed with or furnished to the Commission by the registrant
     pursuant to section 13 or section 15(d) of the Securities Exchange Act of
     1934 that are incorporated by reference in the Registration Statement.
 
          (2) That, for the purpose of determining any liability under the
     Securities Act of 1933, each such post-effective amendment shall be deemed
     to be a new registration statement relating to the securities offered
     therein, and the offering of such securities at that time shall be deemed
     to be the initial bona fide offering thereof.
 
          (3) To remove from registration by means of a post-effective amendment
     any of the securities being registered which remain unsold at the
     termination of the offering.
 
     (b) FILINGS INCORPORATING SUBSEQUENT EXCHANGE ACT DOCUMENTS BY REFERENCE.
The undersigned registrant hereby undertakes that, for purposes of determining
any liability under the Securities Act of 1933, each filing of the registrant's
annual report pursuant to section 13(a) or section 15(d) of the Securities
Exchange Act of 1934 that is incorporated by reference in the registration
statement shall be deemed to be a new registration statement relating to the
securities offered therein, and the offering of such securities at that time
shall be deemed to be the initial bona fide offering thereof.
 
     (c) INDEMNIFICATION. Insofar as indemnification for liabilities arising
under the Securities Act of 1933 may be permitted to directors, officers and
controlling persons of the registrant pursuant to the foregoing provisions, or
otherwise, the registrant has been advised that in the opinion of the Securities
and Exchange Commission such indemnification is against public policy as
expressed in the Act and is, therefore, unenforceable. In the event that a claim
for indemnification against such liabilities (other than the payment by the
registrant of expenses incurred or paid by a director, officer or controlling
person of the registrant in the successful defense of any action, suit or
proceeding) is asserted by such director, officer or controlling person in
connection with the securities being registered, the registrant will, unless in
the opinion of its counsel the matter has been settled by controlling precedent,
submit to a court of appropriate jurisdiction the question whether such
indemnification by it is against public policy as expressed in the Act and will
be governed by the final adjudication of such issue.
 
                                      II-6
<PAGE>   26
 
     (d) REGISTRATION STATEMENT PERMITTED BY RULE 430A. The undersigned
registrant hereby undertakes that:
 
          (1) For purposes of determining any liability under the Securities Act
     of 1933, the information omitted from the form of prospectus filed as part
     of this registration statement in reliance upon Rule 430A and contained in
     a form of prospectus filed by the registrant pursuant to Rule 424(b)(1) or
     (4) or 497(h) under the Securities Act shall be deemed to be part of this
     registration statement as of the time it was declared effective.
 
          (2) For the purpose of determining any liability under the Securities
     Act of 1933, each post-effective amendment that contains a form of
     prospectus shall be deemed to be a new registration statement relating to
     the securities offered therein, and the offering of such securities at that
     time shall be deemed to be the initial bona fide offering thereof.
 
     (e) QUALIFICATION OF TRUST INDENTURES UNDER THE TRUST INDENTURE ACT OF 1939
FOR DELAYED OFFERINGS
 
     The undersigned registrant hereby undertakes to file an application for the
purpose of determining the eligibility of the trustee to act under subsection
(a) of section 310 of the Trust Indenture Act ("Act") in accordance with the
rules and regulations prescribed by the Commission under Section 305(b)(2) of
the Act.
 
                                      II-7
<PAGE>   27
 
                                   SIGNATURES
 
     Pursuant to the requirements of the Securities Act of 1933, the registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-3 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Dallas, State of Texas, on April 20, 1998.
 
                                            ATMOS ENERGY CORPORATION
 
                                            By:     /s/ ROBERT W. BEST
                                              ----------------------------------
                                                  Robert W. Best, Chairman,
                                                           President
                                                 and Chief Executive Officer
 
                               POWER OF ATTORNEY
 
     Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated. Each person whose signature appears below
hereby constitutes and appoints Robert W. Best his true and lawful
attorney-in-fact and agent, with full power of substitution and resubstitution,
for him and in his name, place, and stead, in any and all capacities, to sign
any and all amendments (including post-effective amendments and amendments
thereto) to this Registration Statement, and to file the same, with all exhibits
thereto, and all other documents in connection therewith, with the Securities
and Exchange Commission, granting unto said attorney-in-fact and agent full
power and authority to do and perform each and every act and thing requisite and
necessary to be done, as fully to all intents and purposes as he might or could
do in person, hereby ratifying and confirming all that said attorney-in-fact and
agent or his substitute or substitutes may lawfully do or cause to be done by
virtue hereof.
 
<TABLE>
<CAPTION>
                      SIGNATURE                                      TITLE                        DATE
                      ---------                                      -----                        ----
<C>                                                    <S>                                <C>
 
                 /s/ ROBERT W. BEST                    Chairman, President and Chief         April 20, 1998
- -----------------------------------------------------    Executive Officer (Principal
                   Robert W. Best                        Executive Officer)
 
                 /s/ LARRY J. DAGLEY                   Executive Vice President and Chief    April 20, 1998
- -----------------------------------------------------    Financial Officer (Principal
                   Larry J. Dagley                       Financial Officer)
 
              /s/ DAVID L. BICKERSTAFF                 Vice President and Controller         April 20, 1998
- -----------------------------------------------------    (Principal Accounting Officer)
                David L. Bickerstaff
 
                /s/ TRAVIS W. BAIN II                  Director                              April 15, 1998
- -----------------------------------------------------
                  Travis W. Bain II
 
                   /s/ DAN BUSBEE                      Director                              April 17, 1998
- -----------------------------------------------------
                     Dan Busbee
 
                /s/ RICHARD W. CARDIN                  Director                              April 15, 1998
- -----------------------------------------------------
                  Richard W. Cardin
</TABLE>
 
                                      II-8
<PAGE>   28
 
<TABLE>
<CAPTION>
                      SIGNATURE                                      TITLE                        DATE
                      ---------                                      -----                        ----
<C>                                                    <S>                                <C>
 
                /s/ THOMAS J. GARLAND                  Director                              April 15, 1998
- -----------------------------------------------------
                  Thomas J. Garland
 
                 /s/ GENE C. KOONCE                    Director                              April 17, 1998
- -----------------------------------------------------
                   Gene C. Koonce
 
                /s/ VINCENT J. LEWIS                   Director                              April 15, 1998
- -----------------------------------------------------
                  Vincent J. Lewis
 
               /s/ THOMAS C. MEREDITH                  Director                              April 15, 1998
- -----------------------------------------------------
                 Thomas C. Meredith
 
                /s/ PHILLIP E. NICHOL                  Director                              April 17, 1998
- -----------------------------------------------------
                  Phillip E. Nichol
 
                  /s/ CARL S. QUINN                    Director                              April 15, 1998
- -----------------------------------------------------
                    Carl S. Quinn
 
               /s/ CHARLES K. VAUGHAN                  Director                              April 17, 1998
- -----------------------------------------------------
                 Charles K. Vaughan
 
                 /s/ RICHARD WARE II                   Director                              April 15, 1998
- -----------------------------------------------------
                   Richard Ware II
</TABLE>
 
                                      II-9
<PAGE>   29
 
                                 EXHIBIT INDEX
 
<TABLE>
<CAPTION>
        EXHIBIT
         NUMBER                                  DESCRIPTION
        -------                                  -----------
<C>                      <S>
         1.1             -- Form of Purchase Agreement.*
         4.1             -- Form of Indenture.
         4.2             -- Form of Debt Security.*
         4.3(a)          -- Note Purchase Agreement, dated as of December 21, 1987,
                            by and between the Company and John Hancock Mutual Life
                            Insurance Company (Exhibit 10(c) of Form 8-K filed
                            January 7, 1988 (File No. 0-11249)).
                         Note Purchase Agreement, dated as of December 21, 1987, by
                            and between the Company and John Hancock Charitable Trust
                            I (Agreement is identical to Hancock Agreement listed
                            above except as to the parties thereto and the amounts
                            thereof.).
                         Note Purchase Agreement dated as of December 21, 1987, by
                            and between the Company and Mellon Bank, N.A., Trustee
                            under Master Trust Agreement of AT&T Corporation, dated
                            January 1, 1984, for Employee Pension Plans --
                            AT&T -- John Hancock -- Private Placement (Agreement is
                            identical to Hancock Agreement listed above except as to
                            the parties thereto and the amounts thereof.).
         4.3(b)          -- Amendment to Note Purchase Agreement, dated October 11,
                            1989, by and between the Company and John Hancock Mutual
                            Life Insurance Company revising Note Purchase Agreement
                            dated December 21, 1987 (Exhibit (10(b)(ii) of Form 10-K
                            for fiscal year ended September 30, 1989 (File No.
                            1-10042)).
                         Amendment to Note Purchase Agreement, dated October 11,
                            1989, by and between the Company and John Hancock
                            Charitable Trust I revising Note Purchase Agreement dated
                            December 21, 1987 (Amendment is identical to Hancock
                            amendment listed above except as to the parties thereto
                            and the amounts thereof.).
                         Amendment to Note Purchase Agreement dated October 11, 1989,
                            by and between the Company and Mellon Bank, N.A., Trustee
                            under Master Trust Agreement of AT&T Corporation, dated
                            January 1, 1984, for Employee Pension Plans --
                            AT&T -- John Hancock -- Private Placement revising Note
                            Purchase Agreement dated December 21, 1987 (Amendment is
                            identical to Hancock amendment listed above except as to
                            the parties thereto and the amounts thereof.).
         4.3(c)          -- Amendment to Note Purchase Agreement dated November 12,
                            1991, by and between the Company and John Hancock Mutual
                            Life Insurance Company revising Note Purchase Agreement
                            dated December 21, 1987 (Exhibit 10(b)(iii) of Form 10-K
                            for fiscal year ended September 30, 1991 (File No.
                            1-10042)).
                         Amendment to Note Purchase Agreement, dated November 12,
                            1991, by and between the Company and John Hancock
                            Charitable Trust I revising Note Purchase Agreement dated
                            December 21, 1987 (Amendment is identical to Hancock
                            amendment listed above except as to the parties thereto
                            and the amounts thereof.).
                         Amendment to Note Purchase Agreement, dated November 12,
                            1991, by and between the Company and Mellon Bank, N.A.,
                            Trustee under Master Trust Agreement of AT&T Corporation,
                            dated January 1, 1984, for Employee Pension
                            Plans -- AT&T -- John Hancock -- Private Placement
                            revising Note Purchase Agreement dated December 21, 1987
                            (Amendment is identical to Hancock amendment above except
                            as to the parties thereto and the amounts thereof.).
</TABLE>
<PAGE>   30
 
<TABLE>
<CAPTION>
        EXHIBIT
         NUMBER                                  DESCRIPTION
        -------                                  -----------
<C>                      <S>
         4.3(d)          -- Amendment to Note Purchase Agreement, dated December 22,
                            1993, by and between the Company and John Hancock Mutual
                            Life Insurance Company revising Note Purchase Agreement
                            dated December 21, 1987.
                         Amendment to Note Purchase Agreement, dated December 22,
                            1993, by and between the Company and Mellon Bank, N.A.,
                            Trustee under Master Trust Agreement of AT&T Corporation,
                            dated January 1, 1984, for Employee Pension
                            Plans -- AT&T -- John Hancock -- Private Placement
                            revising Note Purchase Agreement dated December 21, 1987
                            (Amendment is identical to Hancock amendment listed above
                            except as to the parties thereto and the amounts
                            thereof).
         4.3(e)          -- Amendment to Note Purchase Agreement, dated December 20,
                            1994 by and between the Company and John Hancock Mutual
                            Life Insurance Company revising Note Purchase Agreement
                            dated December 21, 1987.
                         Amendment to Note Purchase Agreement, dated December 20,
                            1994, by and between the Company and Mellon Bank, N.A.,
                            Trustee under Master Trust Agreement of AT&T Corporation,
                            dated January 1, 1984, for Employee Pension
                            Plans -- AT&T -- John Hancock -- Private Placement
                            revising Note Purchase Agreement dated December 21, 1987
                            (Amendment is identical to Hancock amendment listed
                            above).
         4.3(f)          -- Amendment to Note Purchase Agreement, dated July 29,
                            1997, by and between the Company and John Hancock Mutual
                            Life Insurance Company revising Note Purchase Agreement
                            dated December 21, 1987.
                         Amendment to Note Purchase Agreement, dated July 29, 1997,
                            by and between the Company and Mellon Bank, N.A., Trustee
                            under Master Trust Agreement of AT&T Corporation, dated
                            January 1, 1984, for Employee Pension Plans --
                            AT&T -- John Hancock -- Private Placement revising Note
                            Purchase Agreement dated December 21, 1987 (Amendment is
                            identical to Hancock Amendment listed above except as to
                            the parties thereto and the amounts thereof).
         4.4(a)          -- Note Purchase Agreement, dated as of October 11, 1989, by
                            and between the Company and John Hancock Mutual Life
                            Insurance Company (Exhibit 10(c) of Form 10-K for fiscal
                            year ended September 30, 1989 (File No. 1-10042)).
         4.4(b)          -- Amendment to Note Purchase Agreement, dated as of
                            November 12, 1991, by and between the Company and John
                            Hancock Mutual Life Insurance Company revising Note
                            Purchase Agreement dated October 11, 1989 (Exhibit
                            10(c)(ii) of Form 10-K for fiscal year ended September
                            30, 1991 (File No. 1-10042)).
         4.4(c)          -- Amendment to Note Purchase Agreement, dated December 22,
                            1993, by and between the Company and John Hancock Mutual
                            Life Insurance Company revising Note Purchase Agreement
                            dated October 11, 1989.
         4.4(d)          -- Amendment to Note Purchase Agreement, dated December 20,
                            1994, by and between the Company and John Hancock Mutual
                            Life Insurance Company revising Note Purchase Agreement
                            dated October 11, 1989.
         4.4(e)          -- Amendment to Note Purchase Agreement, dated July 29,
                            1997, by and between the Company and John Hancock Mutual
                            Life Insurance Company revising Note Purchase Agreement
                            dated October 11, 1989.
         4.5(a)          -- Note Purchase Agreement, dated as of August 29, 1991, by
                            and between the Company and The Variable Annuity Life
                            Insurance Company (Exhibit 10(f)(i) of Form 10-K for
                            fiscal year ended September 30, 1991 (File No. 10042)).
</TABLE>
<PAGE>   31
 
<TABLE>
<CAPTION>
        EXHIBIT
         NUMBER                                  DESCRIPTION
        -------                                  -----------
<C>                      <S>
         4.5(b)          -- Amendment to Note Purchase Agreement, dated November 26,
                            1991, by and between the Company and The Variable Annuity
                            Life Insurance Company revising Note Purchase Agreement
                            dated August 29, 1991 (Exhibit 10(f)(ii) of Form 10-K for
                            fiscal year ended September 30, 1991 (File No. 1-10042)).
         4.5(c)          -- Amendment to Note Purchase Agreement, dated December 22,
                            1993, by and between the Company and The Variable Annuity
                            Life Insurance Company revising Note Purchase Agreement
                            dated August 29, 1991.
         4.5(d)          -- Amendment to Note Purchase Agreement, dated July 29,
                            1997, by and between the Company and The Variable Annuity
                            Life Insurance Company revising Note Purchase Agreement
                            dated August 29, 1991.
         4.6(a)          -- Note Purchase Agreement, dated as of August 31, 1992, by
                            and between the Company and The Variable Annuity Life
                            Insurance Company (Exhibit 10(f) of Form 10-K for fiscal
                            year ended September 30, 1992 (File No. 1-10042)).
         4.6(b)          -- Amendment to Note Purchase Agreement, dated December 22,
                            1993, by and between the Company and the Variable Annuity
                            Life Insurance Company revising Note Purchase Agreement
                            dated August 31, 1992.
         4.6(c)          -- Amendment to Note Purchase Agreement, dated July 29,
                            1997, by and between the Company and The Variable Annuity
                            Life Insurance Company revising Note Purchase Agreement
                            dated August 31, 1992.
         4.7(a)          -- Note Purchase Agreement, dated November 14, 1994, by and
                            among the Company and New York Life Insurance Company,
                            New York Life Insurance and Annuity Corporation, The
                            Variable Annuity Life Insurance Company, American General
                            Life Insurance Company, and Merit Life Insurance Company
                            (Exhibit 10.1 of Form 10-Q for quarter ended December 31,
                            1994 (File No. 1-10042)).
         4.7(b)          -- Amendment to Note Purchase Agreement, dated July 29,
                            1997, by and among the Company and New York Life
                            Insurance Company, New York Life Insurance and Annuity
                            Corporation, The Variable Annuity Life Insurance Company,
                            American General Life Insurance Company and Merit Life
                            Insurance Company revising Note Purchase Agreement dated
                            November 14, 1994.
         4.8             -- Loan Agreement by and between the Company and NationsBank
                            of Texas, N.A. dated as of November 26, 1996 (Exhibit
                            10.1 of Form 10-Q for quarter ended December 31, 1996
                            (File No. 1-10042)).
         4.9(a)          -- Indenture of Mortgage, dated as of July 15, 1959, from
                            United Cities Gas Company to First Trust of Illinois,
                            National Association, and M.J. Kruger, as Trustees, as
                            amended and supplemented through December 1, 1992 (the
                            Indenture of Mortgage through the 20th Supplemental
                            Indenture) (Exhibit to Registration Statement of United
                            Cities Gas Company on Form S-3 (File No. 33-56983)).
         4.9(b)          -- Twenty-First Supplemental Indenture dated as of February
                            5, 1997 by and among United Cities Gas Company and Bank
                            of America Illinois and First Trust National Association
                            and Russell C. Bergman supplementing Indenture of
                            Mortgage dated as of July 15, 1959 (Exhibit 10.7(a) of
                            Form 10-K for the fiscal year ended September 30, 1997
                            (File No. 1-10042)).
         4.9(c)          -- Twenty-Second Supplemental Indenture dated as of July 29,
                            1997 by and among the Company and First Trust National
                            Association and Russell C. Bergman supplementing
                            Indenture of Mortgage dated as of July 15, 1959 (Exhibit
                            10.7(b) of Form 10-K for the fiscal year ended September
                            30, 1997 (File No. 1-10042)).
</TABLE>
<PAGE>   32
 
<TABLE>
<CAPTION>
        EXHIBIT
         NUMBER                                  DESCRIPTION
        -------                                  -----------
<C>                      <S>
         4.10(a)         -- Form of Indenture between United Cities Gas Company and
                            First Trust of Illinois, National Association, as Trustee
                            dated as of November 15, 1995 (Exhibit to Registration
                            Statement of United Cities Gas Company on Form S-3 (File
                            No. 33-56983)).
         4.10(b)         -- First Supplemental Indenture between the Company and
                            First Trust of Illinois, National Association, as Trustee
                            dated as of July 29, 1997 (Exhibit 10.8(a) of Form 10-K
                            for the fiscal year ended September 30, 1997 (File No.
                            1-10042)).
         4.11(a)         -- Seventh Supplemental Indenture, dated as of October 1,
                            1983 between Greeley Gas Company ("the Greeley Gas
                            Division") and the Central Bank of Denver, N.A. ("Central
                            Bank") (Exhibit 10.1 of Form 10-Q for quarter ended June
                            30, 1994 (File No. 1-10042)).
         4.11(b)         -- Ninth Supplemental Indenture, dated as of April 1, 1991,
                            between the Greeley Gas Division and Central Bank
                            (Exhibit 10.2 of Form 10-Q for quarter ended June 30,
                            1994 (File No. 1-10042)).
         4.11(c)         -- Bond Purchase Agreement, dated as of April 1, 1991,
                            between the Greeley Gas Division and Central Bank
                            (Exhibit 10.3 of Form 10-Q for quarter ended June 30,
                            1994 (File No. 1-10042)).
         4.11(d)         -- Tenth Supplemental Indenture, dated as of December 1,
                            1993, between the Company and Colorado National Bank,
                            formerly Central Bank (Exhibit 10.4 of Form 10-Q for
                            quarter ended June 30, 1994 (File No. 1-10042)).
         5.1             -- Opinion of Locke Purnell Rain Harrell (A Professional
                            Corporation) as to certain legal matters.
        12.1             -- Computation of Ratio of Earnings to Fixed Charges of the
                            Company.
        23.1             -- Consent of Ernst & Young LLP.
        23.2             -- Consent of Arthur Andersen LLP.
        23.3             -- Consent of Locke Purnell Rain Harrell (A Professional
                            Corporation) (set forth in its opinion filed as Exhibit
                            5.1).
        24.1             -- Powers of attorney (set forth on the signature page(s)
                            hereof).
        25.1             -- Statement of Eligibility and Qualifications on Form T-1
                            of Trustee under the Indenture.
</TABLE>
 
- ---------------
 
* Such exhibit will be filed by the Registrant as an exhibit to a Current Report
  on Form 8-K and incorporated herein by reference.

<PAGE>   1
                                                                     EXHIBIT 4.1


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




                            ATMOS ENERGY CORPORATION,

                                     Issuer,


                                       to


                     U.S. BANK TRUST NATIONAL ASSOCIATION,

                                     Trustee


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


                                    INDENTURE

                         Dated as of _________ __, 1998



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


                                 Debt Securities


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

<PAGE>   2

               Reconciliation and tie between Trust Indenture Act
              of 1939 and Indenture, dated as of ____________, 1998

<TABLE>
<CAPTION>
Trust Indenture
  Act Section                                                                             Indenture Section

<S>                                                                                       <C>   
Section 310(a)(1)       ..............................................................    607(a)
           (a)(2)       ..............................................................    607(a)
           (b)          ..............................................................    608(b), 609
Section 311(a)          ..............................................................    612
           (b)          ..............................................................    612
Section 312(c)          ..............................................................    701
Section 313             ..............................................................    702
Section 314(a)          ..............................................................    703
           (a)(4)       ..............................................................    1004
           (c)(1)       ..............................................................    102
           (c)(2)       ..............................................................    102
           (e)          ..............................................................    102
Section 315(b)          ..............................................................    601
Section 316(a)(last
           sentence)    ..............................................................    101 ("Outstanding")
           (a)(1)(A)    ..............................................................    502, 512
           (a)(1)(B)    ..............................................................    513
           (b)          ..............................................................    508
           (c)          ..............................................................    104(e)
Section 317(a)(1)       ..............................................................    503
           (a)(2)       ..............................................................    504
           (b)          ..............................................................    1003
Section 318(a)          ..............................................................    108
</TABLE>




<PAGE>   3

                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                                                Page
<S>                                                                                                              <C>
    PARTIES.......................................................................................................1
    RECITALS OF THE COMPANY.......................................................................................1

                                                                  ARTICLE ONE

                                            DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION

    SECTION 101.  Definitions.....................................................................................1
                           Act....................................................................................2
                           Additional Amounts.....................................................................2
                           Affiliate..............................................................................2
                           Attributable Debt......................................................................2
                           Authenticating Agent...................................................................2
                           Authorized Newspaper...................................................................2
                           Authorized Officer.....................................................................2
                           Bankruptcy Law.........................................................................3
                           Board of Directors.....................................................................3
                           Board Resolution.......................................................................3
                           Book-Entry Security....................................................................3
                           Business Day...........................................................................3
                           Capital Stock..........................................................................3
                           Cedel..................................................................................3
                           Commission.............................................................................3
                           Company................................................................................3
                           Company Request or Company Order.......................................................3
                           Consolidated Net Tangible Assets.......................................................4
                           Corporate Trust Office.................................................................4
                           corporation............................................................................4
                           covenant defeasance....................................................................4
                           Custodian..............................................................................4
                           Debt...................................................................................4
                           Default................................................................................4
                           Defaulted Interest.....................................................................4
                           defeasance.............................................................................4
                           Definitive Security....................................................................4
                           Depository.............................................................................4
                           Euroclear..............................................................................4
                           Event of Default.......................................................................5
                           Exchange Act...........................................................................5
</TABLE>

- --------

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


<PAGE>   4

<TABLE>
<CAPTION>
                                                                                                        PAGE
<S>                                                                                                     <C>
                  Extension Notice and Extension Period..................................................5
                  Final Maturity.........................................................................5
                  Funded Indebtedness....................................................................5
                  generally accepted accounting principles or GAAP.......................................5
                  Global Securities......................................................................5
                  Government Obligations.................................................................5
                  Greeley Indenture......................................................................6
                  guarantee..............................................................................6
                  Holder.................................................................................6
                  incorporated provision.................................................................6
                  Indebtedness...........................................................................6
                  Indenture..............................................................................6
                  Indexed Security.......................................................................6
                  interest...............................................................................7
                  Interest Payment Date..................................................................7
                  Lien...................................................................................7
                  Loan Agreement.........................................................................7
                  mandatory sinking fund payment.........................................................7
                  Maturity...............................................................................7
                  Non-Recourse Indebtedness..............................................................7
                  Note Purchase Agreements...............................................................8
                  Officers' Certificate..................................................................8
                  Opinion of Counsel.....................................................................8
                  Option to Elect Repayment..............................................................8
                  Optional Reset Date....................................................................8
                  optional sinking fund payment..........................................................8
                  Original Issue Discount Security.......................................................8
                  Original Stated Maturity...............................................................8
                  Outstanding............................................................................8
                  Paying Agent...........................................................................9
                  Person................................................................................10
                  Place of Payment......................................................................10
                  Predecessor Security..................................................................10
                  Principal Property....................................................................10
                  Redemption Date.......................................................................10
                  Redemption Price......................................................................10
                  Regular Record Date...................................................................10
                  Repayment Date........................................................................10
                  Repayment Price.......................................................................10
                  Reset Notice..........................................................................10
                  Restricted Securities.................................................................11
                  Restricted Subsidiary.................................................................11
                  Sale and Leaseback Transaction........................................................11
                  Securities............................................................................11
                  Security Register and Security Registrar..............................................11
                  Special Record Date...................................................................11
                  Stated Maturity.......................................................................11
                  Subsequent Interest Period............................................................11
                  Subsidiary............................................................................11
</TABLE>


                                       ii
<PAGE>   5
\
<TABLE>
<CAPTION>
                                                                                                             PAGE
<S>                                                                                                          <C>
                        Trust Indenture Act or TIA............................................................12
                        Trustee...............................................................................12
                        United Cities Indenture...............................................................12
                        United States.........................................................................12
                        United States person..................................................................12
                        Vice President........................................................................12
                        Yield to Maturity.....................................................................12
 SECTION 102.  Compliance Certificates and Opinions...........................................................13
 SECTION 103.  Form of Documents Delivered to Trustee.........................................................13
 SECTION 104.  Acts of Holders................................................................................14
 SECTION 105.  Notices, etc. to Trustee and Company...........................................................15
 SECTION 106.  Notice to Holders; Waiver......................................................................16
 SECTION 107.  Conflict of any Provision of Indenture with Trust Indenture Act................................16
 SECTION 108.  Effect of Headings and Table of Contents.......................................................17
 SECTION 109.  Successors and Assigns.........................................................................17
 SECTION 110.  Separability Clause............................................................................17
 SECTION 111.  Benefits of Indenture..........................................................................17
 SECTION 112.  Governing Law..................................................................................17
 SECTION 113.  Legal Holidays.................................................................................17
 SECTION 114.  No Recourse Against Others.....................................................................18


                                                            ARTICLE TWO

                                                          SECURITY FORMS

 SECTION 201.  Forms Generally................................................................................18
 SECTION 202.  Form of Trustee's Certificate of Authentication................................................19
 SECTION 203.  Securities Issuable in Global Form.............................................................19
 SECTION 204.  Form of Legend for Book-Entry Securities.......................................................20


                                                            ARTICLE THREE

                                                            THE SECURITIES

 SECTION 301.  Amount Unlimited; Issuable in Series...........................................................21
 SECTION 302.  Denominations..................................................................................24
 SECTION 303.  Execution, Authentication, Delivery and Dating.................................................24
</TABLE>


                                       iii
<PAGE>   6

<TABLE>
<CAPTION>
                                                                                                                PAGE
<S>                                                                                                             <C>
    SECTION 304.  Book-Entry Securities..........................................................................26
    SECTION 305.  Temporary Securities...........................................................................28
    SECTION 306.  Registration, Registration of Transfer and Exchange............................................29
    SECTION 307.  Mutilated, Destroyed, Lost and Stolen Securities...............................................31
    SECTION 308.  Payment of Interest; Interest Rights Preserved; Optional Interest Reset........................33
    SECTION 309.  Optional Extension of Stated Maturity..........................................................35
    SECTION 310.  Persons Deemed Owners..........................................................................36
    SECTION 311.  Cancellation...................................................................................37
    SECTION 312.  Computation of Interest........................................................................37
    SECTION 313.  CUSIP Numbers..................................................................................38


                                                           ARTICLE FOUR

                                                     SATISFACTION AND DISCHARGE

    SECTION 401.  Satisfaction and Discharge of Indenture........................................................38
    SECTION 402.  Application of Trust Money.....................................................................39


                                                          ARTICLE FIVE

                                                            REMEDIES

    SECTION 501.  Events of Default..............................................................................40
    SECTION 502.  Acceleration of Maturity; Rescission and Annulment.............................................41
    SECTION 503.  Collection of Indebtedness and Suits for Enforcement by Trustee................................42
    SECTION 504.  Trustee May File Proofs of Claim...............................................................43
    SECTION 505.  Trustee May Enforce Claims Without Possession of Securities....................................44
    SECTION 506.  Application of Money Collected.................................................................44
    SECTION 507.  Limitation on Suits............................................................................45
    SECTION 508.  Unconditional Right of Holders
                           to Receive Principal, Premium and Interest............................................45
    SECTION 509.  Restoration of Rights and Remedies.............................................................46
    SECTION 510.  Rights and Remedies Cumulative.................................................................46
    SECTION 511.  Delay or Omission Not Waiver...................................................................46
    SECTION 512.  Control by Holders.............................................................................46
    SECTION 513.  Waiver of Past Defaults........................................................................47
    SECTION 514.  Undertaking for Costs..........................................................................47
    SECTION 515.  Waiver of Stay or Extension Laws...............................................................48
</TABLE>


                                       iv
<PAGE>   7

<TABLE>
<CAPTION>
                                                                                                                PAGE
<S>                                                                                                             <C>
                                                           ARTICLE SIX

                                                           THE TRUSTEE

    SECTION 601.  Notice of Defaults.............................................................................48
    SECTION 602.  Certain Rights of Trustee......................................................................49
    SECTION 603.  Trustee Not Responsible for Recitals or Issuance of Securities.................................50
    SECTION 604.  May Hold Securities............................................................................50
    SECTION 605.  Money Held in Trust............................................................................50
    SECTION 606.  Compensation and Reimbursement.................................................................51
    SECTION 607.  Conflicting Interests..........................................................................51
    SECTION 608.  Corporate Trustee Required; Eligibility; Conflicting Interests.................................52
    SECTION 609.  Resignation and Removal; Appointment of Successor..............................................52
    SECTION 610.  Acceptance of Appointment by Successor.........................................................54
    SECTION 611.  Merger, Conversion, Consolidation or Succession to Business....................................55
    SECTION 612.  Appointment of Authenticating Agent............................................................55
    SECTION 613.  Preferential Collection of Claims Against Company..............................................57


                                                          ARTICLE SEVEN

                                        HOLDERS' LISTS AND REPORTS BY TRUSTEE AND COMPANY

    SECTION 701.  Disclosure of Names and Addresses of Holders...................................................57
    SECTION 702.  Reports by Trustee.............................................................................58
    SECTION 703.  Reports by Company.............................................................................58


                                                         ARTICLE EIGHT

                                     CONSOLIDATION, MERGER, CONVEYANCE, TRANSFER OR LEASE

    SECTION 801.  Company May Consolidate, Etc., Only on Certain Terms...........................................59
    SECTION 802.  Rights and Duties of Successor Corporation.....................................................59
    SECTION 803.  Securities to be Secured in Certain Events.....................................................60
</TABLE>



                                        v
<PAGE>   8

<TABLE>
<CAPTION>
                                                                                                                PAGE
<S>                                                                                                            <C>
                                                              ARTICLE NINE

                                                         SUPPLEMENTAL INDENTURES

    SECTION 901.    Supplemental Indentures Without Consent of Holders.............................................61
    SECTION 902.    Supplemental Indentures with Consent of Holders................................................62
    SECTION 903.    Execution of Supplemental Indentures...........................................................63
    SECTION 904.    Effect of Supplemental Indentures..............................................................64
    SECTION 905.    Conformity with Trust Indenture Act............................................................64
    SECTION 906.    Reference in Securities to Supplemental Indentures.............................................64
    SECTION 907.    Notice of Supplemental Indentures..............................................................64


                                                             ARTICLE TEN

                                                              COVENANTS

    SECTION 1001.   Payment of Principal, Premium and Interest.....................................................64
    SECTION 1002.   Maintenance of Office or Agency................................................................65
    SECTION 1003.   Money for Security Payments to Be Held in Trust................................................65
    SECTION 1004.   Statement as to Compliance.....................................................................67
    SECTION 1005.   Corporate Existence............................................................................67
    SECTION 1006.   Limitations on Liens...........................................................................67
    SECTION 1007.   Limitation on Sale and Leaseback Transactions..................................................67
    SECTION 1008.   Additional Amounts.............................................................................67
    SECTION 1009.   Waiver of Certain Covenants....................................................................69


                                                           ARTICLE ELEVEN

                                                      REDEMPTION OF SECURITIES

    SECTION 1101.   Applicability of Article.......................................................................69
    SECTION 1102.   Election to Redeem; Notice to Trustee..........................................................69
    SECTION 1103.   Selection by Trustee of Securities to Be Redeemed..............................................70
    SECTION 1104.   Notice of Redemption...........................................................................70
    SECTION 1105.   Deposit of Redemption Price....................................................................71
    SECTION 1106.   Securities Payable on Redemption Date..........................................................71
    SECTION 1107.   Securities Redeemed in Part....................................................................72
</TABLE>



                                       vi
<PAGE>   9

<TABLE>
<CAPTION>
                                                                                                           PAGE
<S>                                                                                                         <C>
                                                         ARTICLE TWELVE

                                                         SINKING FUNDS

 SECTION 1201.  Applicability of Article......................................................................72
 SECTION 1202.  Satisfaction of Sinking Fund Payments with Securities.........................................73
 SECTION 1203.  Redemption of Securities for Sinking Fund.....................................................73


                                                        ARTICLE THIRTEEN

                                                  REPAYMENT AT OPTION OF HOLDERS

 SECTION 1301.  Applicability of Article......................................................................74
 SECTION 1302.  Repayment of Securities.......................................................................75
 SECTION 1303.  Exercise of Option............................................................................75
 SECTION 1304.  When Securities Presented for Repayment Become Due and Payable................................76
 SECTION 1305.  Securities Repaid in Part.....................................................................76


                                                        ARTICLE FOURTEEN

                                               DEFEASANCE AND COVENANT DEFEASANCE

 SECTION 1401.  Company's Option to Effect Defeasance or Covenant Defeasance..................................77
 SECTION 1402.  Defeasance and Discharge......................................................................77
 SECTION 1403.  Covenant Defeasance...........................................................................78
 SECTION 1404.  Conditions to Defeasance or Covenant Defeasance...............................................78
 SECTION 1405.  Deposited Money and Government Obligations to Be Held in Trust; Other
                        Miscellaneous Provisions..............................................................80
 SECTION 1406.  Reinstatement.................................................................................81

</TABLE>






                                       vii
<PAGE>   10
         INDENTURE, dated as of ________ __, 1998 between Atmos Energy
Corporation, a Texas and Virginia corporation (herein called the "Company"), and
U.S. Bank Trust National Association, a national banking association with trust
powers, trustee (herein called the "Trustee").

                             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 senior debt
securities (herein called the "Securities"), to be issued in one or more series
as in this Indenture provided.

         This Indenture is subject to the provisions of the Trust Indenture Act
of 1939, as amended, that are required to be part of this Indenture and shall,
to the extent applicable, 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 have the meanings assigned to
     them in this Article and include the plural as well as the singular;

         (2) all other terms used herein which are defined in the Trust
     Indenture Act, either directly or by reference therein, have the meanings
     assigned to them therein, and the terms "cash transaction" and
     "self-liquidating paper", as used in TIA Section 311,


<PAGE>   11

                                        2

     shall have the meanings assigned to them in the rules of the Commission
     adopted under the Trust Indenture Act;

         (3) all accounting terms not otherwise defined herein have the meanings
     assigned to them in accordance with generally accepted accounting
     principles 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; and

         (4) 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 Three, are defined in that
Article.

         "Act", when used with respect to any Holder, has the meaning specified
in Section 104.

         "Additional Amounts" has the meaning specified in Section 1008.

         "Affiliate" means, with respect to any specified Person, 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.

         "Attributable Debt" means, as to any particular lease under which any
Person is at the time liable, at any date as of which the amount thereof is to
be determined, the total net amount of rent required to be paid by such Person
under such lease during the remaining term thereof (excluding amounts required
to be paid on account of maintenance and repairs, services, insurance, taxes,
assessments, water rates and similar charges and contingent rents), discounted
from the respective due dates thereof at the weighted average of the rates of
interest (or Yield to Maturity, in the case of Original Issue Discount
Securities) borne by the Indenture Securities then outstanding under the
Indenture, compounded annually.

         "Authenticating Agent" means any Person appointed by the Trustee to act
on behalf of the Trustee pursuant to Section 611 to authenticate Securities.

         "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 each place in connection with which the term is
used or in the financial community of each 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.

         "Authorized Officer", when used with respect to the Trustee, means any
vice-president, assistant vice president, any assistant secretary, any assistant
treasurer, any trust officer or assistant trust officer, the controller and any
assistant controller or any other officer of the Trustee customarily performing
functions similar to those performed by any of the above-designated officers or
assigned by the Trustee to administer corporate trust matters at its Corporate
Trust Office 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.
<PAGE>   12
 
                                        3

         "Bankruptcy Law" means Title 11, U.S. Code or any similar federal or
state law for the relief of debtors.

         "Board of Directors" means the Board of Directors of the Company or any
duly authorized committee of such Board.

         "Board Resolution" means a copy of a resolution certified by the
Corporate Secretary or an Assistant Corporate 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.

         "Book-Entry Security" has the meaning specified in Section 304.

         "Business Day", when used with respect to any Place of Payment or any
other particular location referred to in this Indenture or in the Securities,
means, unless otherwise specified with respect to any Securities pursuant to
Section 301, each Monday, Tuesday, Wednesday, Thursday and Friday which is not a
day on which banking institutions in that Place of Payment or other location are
authorized or obligated by law, regulation or executive order to close.

         "Capital Stock" means, with respect to any corporation, any and all
shares, interests, rights to purchase, warrants, options, participations or
other equivalents of or interests (however designated) in stock issued by that
corporation.

         "Cedel" means Cedel Bank, societe anonyme, or its successor.
 
         "Commission" means the Securities and Exchange Commission, as from time
to time constituted, created under the Exchange Act 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 Indenture until a successor Person shall have become such
pursuant to the applicable provisions of this Indenture, and thereafter
"Company" shall mean such successor Person. To the extent necessary to comply
with the requirements of the provisions of TIA Sections 310 through 317 as they
are applicable to the Company, the term "Company" shall include any other
obligor with respect to the Securities for the purposes of complying with such
provisions.

         "Company Request" or "Company Order" means a written request or order
signed in the name of the Company (i) by its Chairman, Chief Executive Officer,




<PAGE>   13

                                        4

its President or a Vice President and (ii) by its Treasurer, an Assistant
Treasurer, its Corporate Secretary or an Assistant Corporate Secretary and
delivered to the Trustee; provided, however, that such written request or order
may be signed by any two of the officers or directors listed in clause (i) above
in lieu of being signed by one of such officers or directors listed in such
clause (i) and one of the officers listed in clause (ii) above.

         "Consolidated Net Tangible Assets" means the aggregate amount of assets
(less applicable reserves and other properly deductible items) after deducting
therefrom (i) all current liabilities (excluding any portion thereof
constituting Funded Indebtedness) and (ii) all goodwill, trade names,
trademarks, patents, unamortized debt discount and expense and other like
intangibles, all as set forth on the most recent consolidated balance sheet of
the Company contained in the latest annual report to shareholders of the Company
and computed in accordance with generally accepted accounting principles.

         "Corporate Trust Office" means the office of the Trustee at which at
any particular time its corporate trust business shall be principally
administered, which office on the date of execution of this Indenture is located
at One Illinois Center, 111 East Wacker Drive, Suite 3000, Chicago, Illinois
60601, Attention: Corporate Trust Department.

         "corporation" includes corporations, associations, partnerships,
limited liability companies, companies and business trusts.

         "covenant defeasance" has the meaning specified in Section 1403 hereof.

         "Custodian" means any receiver, trustee, assignee, liquidator,
sequestrator or similar officer under any Bankruptcy Law.

         "Debt" means notes, bonds, debentures or other similar evidences of
indebtedness for money borrowed.

         "Default" means any event that is, or after notice or passage of time
or both would be, an Event of Default.

         "Defaulted Interest" has the meaning specified in Section 308 hereof.

         "defeasance" has the meaning specified in Section 1402 hereof.

         "Definitive Security" has the meaning specified in Section 304 hereof.

         "Depository" has the meaning specified in Section 304.

         "Euroclear" means Morgan Guaranty Trust Company of New York, Brussels
Office, or its successor as operator of the Euroclear System. 



<PAGE>   14

                                        5

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

         "Exchange Act" means the Securities Exchange Act of 1934, as amended.

         "Extension Notice" and "Extension Period" shall have the meanings
specified in Section 309.

         "Final Maturity" has the meaning specified in Section 309.

         "Funded Indebtedness" as applied to any Person, means all Indebtedness
of such Person maturing after, or renewable or extendable at the option of such
Person beyond, 12 months from the date of determination.

         "generally accepted accounting principles" or "GAAP" means generally
accepted accounting principles in the United States.

         "Global Securities" means one or more Securities evidencing all or part
of the Securities to be issued as Book-Entry Securities, issued to the
Depository in accordance with Section 301 and bearing the legend prescribed in
Section 204.

         "Government Obligations" means, unless otherwise specified with respect
to any series of Securities pursuant to Section 301, securities which are (i)
direct obligations of the United States government or (ii) obligations of a
Person controlled or supervised by and acting as an agency or instrumentality of
the United States government, the payment of which is unconditionally guaranteed
by the United States government, which, in either case, are full faith and
credit obligations of the United States government payable and are not callable
or redeemable at the option of the issuer thereof and shall also include a
depository receipt issued by a bank or trust company as custodian with respect
to any such Government Obligation or a specific payment of interest on or
principal of any such Government Obligation held by such custodian for the
account of the holder of a depository receipt; provided that (except as required
by law) such custodian is not authorized to make any deduction from the amount
payable to the holder of such depository receipt from any amount received by the
custodian in respect of the Government Obligation or the specific payment of
interest or principal of the Government Obligation evidenced by such depository
receipt.




<PAGE>   15

                                        6

         "Greeley Indenture" means that certain Indenture of Mortgage and Deed
of Trust, dated as of March 1, 1957, from Greeley Gas Company to U.S. Bank 
National Association (formerly The Central Bank and Trust Company), as Trustee,
as amended and supplemented through December 1, 1993 (the Indenture of Mortgage
and Deed of Trust through the Tenth Supplemental Indenture by the Company to
U.S. Bank National Association (formerly The Central Bank and Trust Company), as
Trustee.)

         "guarantee" means, as applied to any obligation, (i) a guarantee (other
than by endorsement of negotiable instruments for collection in the ordinary
course of business), direct or indirect, in any manner, of any part or all of
such obligation or (ii) an agreement, direct or indirect, contingent or
otherwise, providing assurance of the payment or performance (or payment of
damages in the event of non-performance) of any part or all of such obligation,
including, without limiting the foregoing, the payment of amounts drawn down by
letters of credit. Notwithstanding anything herein to the contrary, a guarantee
shall not include any agreement solely because such agreement creates a Lien on
the assets of any Person. The amount of a guarantee shall be deemed to be the
maximum amount of the obligation guaranteed for which the guarantor could be
held liable under such guarantee.

         "Holder" means the Person in whose name a Security is registered in the
Security Register.

         "incorporated provision" has the meaning specified in Section 107.

         "Indebtedness" means obligations for money borrowed, evidenced by
notes, bonds, debentures or other similar evidences of indebtedness.

         "Indenture" means this instrument as originally executed (including all
exhibits and schedules hereto) and 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; provided,
however, that, if at any time more than one Person is acting as Trustee under
this instrument, "Indenture" shall mean, with respect to any one or more series
of Securities for which such Person is Trustee, 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
for which such Person is Trustee established as contemplated by Section 301,
exclusive, however, of any provisions or terms which relate solely to other
series of Securities for which such Person is not Trustee, regardless of when
such terms or provisions were adopted, and exclusive of any provisions or terms
adopted by means of one or more indentures supplemental hereto executed and
delivered after such Person had become such Trustee but to which such Person, as
such Trustee, was not a party.

         "Indexed Security" means a Security the terms of which provide that the
principal amount thereof payable at Stated Maturity may be more or less than the
principal face amount thereof at original issuance.




<PAGE>   16

                                        7

         "interest", when used with respect to an Original Issue Discount
Security which by its terms bears interest only after Maturity, means interest
payable after Maturity at the rate prescribed in such Original Issue Discount
Security.

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

         "Lien" means any lien, mortgage, pledge, encumbrance, charge or
security interest securing Indebtedness; provided, however, that the following
types of transactions will not be considered for purposes of this definition to
result in a Lien: (i) any acquisition by the Company or any Restricted
Subsidiary of any property or assets subject to any reservation or exception
under the terms of which any vendor, lessor or assignor creates, reserves or
excepts or has created, reserved or excepted an interest in oil, gas or any
other mineral in place or the proceeds thereof, (ii) any conveyance or
assignment whereby the Company or any Restricted Subsidiary conveys or assigns
to any Person or Persons an interest in oil, gas or any other mineral in place
or the proceeds thereof, (iii) any Lien upon any property or assets either owned
or leased by the Company or any Restricted Subsidiary or in which the Company or
any Restricted Subsidiary owns an interest that secures for the benefit of the
Person or Persons paying the expenses of developing or conducting operations for
the recovery, storage, transportation or sale of the mineral resources of the
such property or assets (or property or assets with which it is unitized) the
payment to such Person or Persons of the Company's or the Restricted
Subsidiary's proportionate part of such development or operating expenses, (iv)
any hedging arrangements entered into in the ordinary course of business,
including any obligation to deliver any mineral, commodity or asset in
connection therewith or (v) any guarantees by the Company of the repayment of
Indebtedness of any Subsidiary or guarantees by any Subsidiary of the repayment
of Indebtedness of any entity, including, but not limited to, Indebtedness of
Woodward Marketing, L.L.C.

         "Loan Agreement" means that certain Loan Agreement by and between the
Company and NationsBank of Texas, N.A., dated as of November 26, 1996.

         "mandatory sinking fund payment" shall have the meaning specified in
Section 1201.

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

         "Non-Recourse Indebtedness" means, at any time, Indebtedness incurred
after the date of the Indenture by the Company or a Restricted Subsidiary in
connection with the acquisition of property or assets by the Company or a
Restricted Subsidiary or the financing of the construction of or improvements on
property, whenever acquired, provided that, under the terms of such Indebtedness
and pursuant to applicable law, the recourse at such time and thereafter of the
lenders with respect to such Indebtedness is limited to the property or assets



<PAGE>   17

                                        8

so acquired, or such construction or improvements, including Indebtedness as to
which a performance or completion guarantee or similar undertaking was initially
applicable to such Indebtedness or the related property or assets if such
guarantee or similar undertaking has been satisfied and is no longer in effect.

         "Note Purchase Agreements" collectively refers to the following Note
Purchase Agreements, as amended, which were executed by and between the Company
and the following parties on the dates indicated: (i) John Hancock Mutual Life
Insurance Company, dated December 21, 1987; (ii) Mellon Bank, N.A., Trustee
under Master Trust Agreement of AT&T Corporation, dated January 1, 1984, for
Employee Pension Plans--AT&T--John Hancock--Private Placement, dated December
21, 1987 (Agreement is identical to Hancock Agreement listed above except as to
the parties thereto and the amounts thereof); (iii) John Hancock Mutual Life
Insurance Company, dated October 11, 1989; (iv) The Variable Annuity Life
Insurance Company, dated August 29, 1991; (v) The Variable Annuity Life
Insurance Company, dated August 31, 1992; and (vi) New York Life Insurance
Company, New York Life Insurance and Annuity Corporation, The Variable Annuity
Life Insurance Company, American General Life Insurance Company and Merit Life
Insurance Company, dated November 14, 1994.

         "Officers' Certificate" means a certificate signed by (i) the Chairman,
Chief Executive Officer, the President, a Vice President or the Treasurer of the
Company and (ii) the Corporate Secretary or an Assistant Corporate Secretary of
the Company and delivered to the Trustee; provided, however, that such
certificate may be signed by two of the officers or directors listed in clause
(i) above in lieu of being signed by one of such officers or directors listed in
such clause (i) and one of the officers listed in clause (ii) above.

         "Opinion of Counsel" means a written opinion of counsel, who may be
counsel for the Company, and who shall be acceptable to the Trustee. Each such
opinion shall include the statements provided for in TIA Section 314(e) to the
extent applicable.

         "Option to Elect Repayment" shall have the meaning specified in Section
1303.

         "Optional Reset Date" shall have the meaning specified in Section 308.

         "optional sinking fund payment" shall have the meaning specified in
Section 1201.

         "Original Issue Discount Security" means any Security which 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.

         "Original Stated Maturity" shall have the meaning specified in Section
309.

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

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

         (ii) Securities, or portions thereof, for whose payment, purchase,
     redemption or repayment at the option of the Holder money in the necessary
     amount has been theretofore deposited with the Trustee or any Paying Agent
     (other than the Company) in



<PAGE>   18

                                        9

     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;

         (iii) Securities, except to the extent provided in Sections 1402 and
     1403, with respect to which the Company has effected defeasance and/or
     covenant defeasance as provided in Article Fourteen; and

         (iv) Securities paid pursuant to Section 307 or Securities 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 Outstanding Securities have given any request, demand,
direction, consent or waiver hereunder or are present at a meeting of Holders
for quorum purposes, and for the purpose of making the calculations required by
TIA Section 313, (i) the principal amount of an Original Issue Discount Security
that may be counted in making such determination or calculation and that shall
be deemed to be Outstanding for such purpose shall be equal to the amount of
principal thereof that would be (or shall have been declared to be) due and
payable, at the time of such determination, upon a declaration of acceleration
of the maturity thereof pursuant to Section 502, (ii) the principal amount of
any Indexed Security that may be counted in making such determination or
calculation and that shall be deemed outstanding for such purpose shall be equal
to the principal face amount of such Indexed Security at original issuance,
unless otherwise provided with respect to such Security pursuant to Section 301,
and (iii) 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 making such calculation or in relying
upon any such request, demand, authorization, direction, notice, consent or
waiver, only Securities which the Trustee actually 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 such other obligor.

         "Paying Agent" means any Person (including the Company acting as Paying
Agent) authorized by the Company to pay the principal of (or premium, if any) or
interest, if any, on any Securities on behalf of the Company.



<PAGE>   19

                                       10

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

         "Place of Payment" means, when used with respect to the Securities of
or within any series, the place or places where the principal of (and premium,
if any) and interest, if any, on such Securities are payable as specified as
contemplated by Sections 301 and 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 307 in exchange for a mutilated
Security or in lieu of a destroyed, lost or stolen Security shall be deemed to
evidence the same debt as the mutilated, destroyed, lost or stolen Security.

         "Principal Property" means any natural gas distribution property or
propane property located in the United States, except any such property that in
the opinion of the Board of Directors of the Company is not of material
importance to the total business conducted by the Company and its consolidated
Subsidiaries. 

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

         "Regular Record Date" for the interest payable on any Interest Payment
Date on the Securities of or within any series means the date specified for that
purpose as contemplated by Section 301.

         "Repayment Date" means, when used with respect to any Security to be
repaid at the option of the Holder, the date fixed for such repayment pursuant
to this Indenture.

         "Repayment Price" means, when used with respect to any Security to be
repaid at the option of the Holder, the price at which it is to be repaid
pursuant to this Indenture.

         "Reset Notice" shall have the meaning specified in Section 308.

<PAGE>   20

                                       11

         "Restricted Securities" has the meaning specified in Section 1006.

         "Restricted Subsidiary" means any Subsidiary that owns or leases a
Principal Property.

         "Sale and Leaseback Transaction" means any arrangement with any Person
pursuant to which the Company or any Restricted Subsidiary leases any Principal
Property that has been or is to be sold or transferred by the Company or the
Restricted Subsidiary to such Person, other than (i) a lease for a term,
including renewals at the option of the lessee, of not more than three years or
classified as an operating lease under generally accepted accounting principles,
(ii) leases between the Company and a Restricted Subsidiary or between
Restricted Subsidiaries and (iii) leases of a Principal Property executed by the
time of, or within 12 months after the latest of, the acquisition, the
completion of construction or improvement, or the commencement of commercial
operation, of the Principal Property.

         "Securities" has the meaning stated in the first recital of this
Indenture and more particularly means any Securities authenticated and delivered
under this Indenture; provided, however, that if at any time there is more than
one Person acting as Trustee under this Indenture, "Securities" with respect to
the Indenture as to which such Person is Trustee shall have the meaning stated
in the first recital of this Indenture and shall more particularly mean
Securities authenticated and delivered under this Indenture, exclusive, however,
of Securities of any series as to which such Person is not Trustee.

         "Security Register" and "Security Registrar" have the respective
meanings specified in Section 306.

         "Special Record Date" means a date fixed by the Trustee for the payment
of any Defaulted Interest pursuant to Section 308.

         "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 representing such installment of principal or interest as the
fixed date on which the principal of such Security or such installment of
principal or interest is due and payable, as such date may be extended pursuant
to the provisions of Section 309.

         "Subsequent Interest Period" shall have the meaning specified in
Section 308.

         "Subsidiary" of the Company means (i) a corporation, a majority of
which Capital Stock with voting power, under ordinary circumstances, to elect
directors is owned, directly or indirectly, at the date of determination, by the
Company, by one or more Subsidiaries or by the Company and one or more
Subsidiaries or (ii) any other Person (other than a corporation) in which at the
date of determination the Company, one or more



<PAGE>   21

                                      12

Subsidiaries or the Company and one or more Subsidiaries, directly or
indirectly, has at least a majority ownership and power to direct the policies,
management and affairs thereof.

         "Trust Indenture Act" or "TIA" means the Trust Indenture Act of 1939,
as amended, and as in force at the date as of which this Indenture was executed,
except as provided in Section 905.

         "Trustee" means the Person named as the "Trustee" in the first
paragraph of this Indenture 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;
provided, however, that if at any time there is more than one such Person,
"Trustee" as used with respect to the Securities of any series shall mean only
the Trustee with respect to Securities of that series.

         "United Cities Indenture" means that certain Indenture of Mortgage,
dated as of July 15, 1959, from United Cities Gas Company to U.S. Bank Trust
National Association (formerly First Trust of Illinois, National Association),
and M.J. Kruger, as Trustees, as amended and supplemented through July 29, 1997
(the Indenture of Mortgage through the Twenty-Second Supplemental Indenture by
the Company to U.S. Bank Trust National Association (formerly First Trust
National Association) and Russell C. Bergman, as Trustees).

         "United States" means, unless otherwise specified with respect to any
Securities pursuant to Section 301, the United States of America (including the
states and the District of Columbia), its territories, its possessions and other
areas subject to its jurisdiction.

         "United States person" means, unless otherwise specified with respect
to any Securities pursuant to Section 301, an individual who is a citizen or
resident of the United States, a corporation, partnership or other entity
created or organized in or under the laws of the United States or an estate or
trust the income of which is subject to United States federal income taxation
regardless of its source.

         "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".

         "Yield to Maturity" means the yield to maturity, computed at the time
of issuance of a Security (or, if applicable, at the most recent redetermination
of interest on such Security) and as set forth in such Security in accordance
with generally accepted United States bond yield computation principles.




<PAGE>   22

                                       13

         SECTION 102. Compliance Certificates and Opinions.

         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 (including any covenant compliance with
which constitutes a condition precedent) relating to the proposed action have
been complied with and an Opinion of Counsel stating that in the opinion of such
counsel all such conditions precedent, if any, have been complied with, except
that in the case of any such application or request as to which the furnishing
of such documents is specifically required by any provision of this Indenture
relating to such particular application or request, no additional certificate or
opinion need be furnished.

         Every certificate or opinion (other than the certificates required by
Section 1004) with respect to compliance with a covenant or condition provided
for in this Indenture shall include:

         (1) a statement that each individual 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 individual, he has
     made such examination or investigation as is necessary to enable him 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 individual,
     such covenant or condition has been complied with.

         SECTION 103. 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,



<PAGE>   23

                                       14

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 104. Acts of Holders.

         (a) Any request, demand, authorization, direction, notice, consent,
waiver or other action provided by this Indenture to be given or taken by
Holders of the Outstanding Securities of all series or one or more series, as
the case may be, may be embodied in and evidenced by one or more instruments of
substantially similar tenor signed by such Holders in person or by agents 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 or so voting at any
such meeting. Proof of execution of any such instrument or of a writing
appointing any such agent, or of the holding by any Person of a Security, shall
be sufficient for any purpose of this Indenture and (subject to TIA Section 315)
conclusive in favor of the Trustee and the Company, if made in the manner
provided in this Section. 

         (b) The fact and date of the execution by any Person of any such
instrument or writing may be proved in any reasonable manner which the Trustee
deems sufficient.

         (c) The ownership of Securities shall be proved by the Security
Register.

         (d) If the Company shall solicit from the Holders of Securities any
request, demand, authorization, direction, notice, consent, waiver or other Act,
the Company may, at its option, by or pursuant to a Board Resolution, fix in
advance a record date for the determination of such Holders entitled to give
such request, demand, authorization, direction, notice, consent, waiver or other
Act, but the Company shall have no obligation to do so.



<PAGE>   24

                                       15

Notwithstanding TIA Section 316(c), any such record date shall be the record
date specified in or pursuant to such Board Resolution, which shall be a date
not more than 30 days prior to the first solicitation of Holders generally in
connection therewith and no later than the date such solicitation is completed.
If such a record date is fixed, such request, demand, authorization, direction,
notice, consent, waiver or other Act may be given before or after such record
date, but only the Holders of record at the close of business on such record
date shall be deemed to be Holders for the purposes of determining whether
Holders of the requisite proportion of Securities then Outstanding have
authorized or agreed or consented to such request, demand, authorization,
direction, notice, consent, waiver or other Act, and for that purpose the
Securities then Outstanding shall be computed as of such record date; provided
that no such request, demand, authorization, direction, notice, consent, waiver
or other Act by the Holders on such record date shall be deemed effective unless
it shall become effective pursuant to the provisions of this Indenture not later
than six months after the record date.

         (e) Any request, demand, authorization, direction, notice, consent,
waiver or other Act by the Holder of any Security shall bind every future Holder
of the same Security or 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, suffered or omitted to be done by the Trustee, any
Paying Agent or the Company in reliance thereon, whether or not notation of such
action is made upon such Security.

         SECTION 105. 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, an agent of any bank or the Company
     shall be sufficient for every purpose hereunder if made, given, furnished
     or delivered, in writing, to or with the Trustee at its Corporate Trust
     Office, Attention: Corporate Trust 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
     made, given, furnished or delivered, in writing, to the Company addressed
     to it c/o 1800 Three Lincoln Centre, 5430 LBJ Freeway, Dallas, Texas 75240,
     Attention: Treasurer, or at any other address previously furnished in
     writing to the Trustee by the Company.




<PAGE>   25

                                       16

         SECTION 106. Notice to Holders; Waiver.

         Where this Indenture provides for notice of any event to Holders of
Securities by the Company or the Trustee, such notice shall be sufficiently
given (unless otherwise herein expressly provided) if in writing and mailed,
first-class postage prepaid, to each Holder affected by such event, at his
address 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 any case where 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 shall affect the sufficiency of such notice with
respect to other Holders of Securities. Any notice mailed to a Holder in the
aforesaid manner shall be conclusively deemed to have been received by such
Holder, whether or not such Holder actually receives such notice.

         In case, by reason of the suspension of or irregularities in regular
mail service or by reason of any other cause, it shall be impractical to mail
notice of any event to Holders of Securities when such notice is required to be
given pursuant to any provision of this Indenture, then any manner of giving
such notice as shall be satisfactory to the Trustee shall be deemed to be
sufficient giving of such notice for every purpose hereunder.

         Any request, demand, authorization, direction, notice, consent or
waiver required or permitted under this Indenture shall be in the English
language, except that any published notice may be in an official language of the
country of publication.

         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 107. Conflict of any Provision of Indenture with Trust
Indenture Act.

         If and to the extent that any provision of this Indenture limits,
qualifies or conflicts with the duties imposed by TIA Sections 310 to 318,
inclusive, or conflicts with any provision (an "incorporated provision")
required by or deemed to be included in this Indenture by operation of such TIA
Sections, such imposed duties or incorporated provision 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 latter provision shall be
deemed to apply to this Indenture as so modified or excluded, as the case may
be.





<PAGE>   26

                                       17

         SECTION 108. 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 109. Successors and Assigns.

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

         SECTION 110. Separability Clause.

         In case any provision in this Indenture or in any Security 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 111. Benefits of Indenture.

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

         SECTION 112. Governing Law.

         This Indenture and the Securities shall be governed by and construed in
accordance with the laws of the State of New York, without regard to conflicts
of laws principles. This Indenture is subject to the provisions of the Trust
Indenture Act that are required to be part of this Indenture and shall, to the
extent applicable, be governed by such provisions.

         SECTION 113. Legal Holidays.

         In any case where any Interest Payment Date, Redemption Date, sinking
fund payment date or Stated Maturity or 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 any Security other than a provision in the Securities of
any series which specifically states that such provision shall apply in lieu of
this Section), payment of principal (or premium, if any) or interest, if any,
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 sinking
fund payment date, or at the Stated Maturity or Maturity; provided that no
interest shall accrue for



<PAGE>   27

                                       18

the period from and after such Interest Payment Date, Redemption Date, sinking
fund payment date, Stated Maturity or Maturity, as the case may be.

         SECTION 114. 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
Securities or this Indenture or for any claim based on, in respect of or by
reason of such obligations or their creation. Each Holder by accepting any of
the Securities waives and releases all such liability.


                                   ARTICLE TWO

                                 SECURITY FORMS

         SECTION 201. Forms Generally.

         The Securities shall be in substantially the forms 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 executing such Securities, as evidenced by their
execution of the Securities. If the forms of Securities of any series are
established by action taken pursuant to a Board Resolution, a copy of an
appropriate record of such action shall be certified by the Corporate Secretary
or an Assistant Corporate Secretary of the Company and 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. Any portion of the text of
any Security may be set forth on the reverse thereof, with an appropriate
reference thereto on the face of the Security.

         The Trustee's certificate of authentication on all Securities shall be
in substantially the form set forth in this Article.

         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 of the Company executing such Securities, as evidenced by their
execution of such Securities.




<PAGE>   28

                                       19

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

         Subject to Section 612, the Trustee's certificate of authentication
shall be in substantially the following form:

                     TRUSTEE'S CERTIFICATE OF AUTHENTICATION

         Dated: ____________________

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

                                      U.S. BANK TRUST NATIONAL ASSOCIATION
                                             as Trustee


                                      By
                                        -------------------------------------
                                        Authorized Officer

         SECTION 203. Securities Issuable in Global Form.

         When Securities of or within a series are issued in global form, as
specified as contemplated by Section 301, then, 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 of such series from time to time endorsed thereon and
that the aggregate amount of Outstanding Securities of such series represented
thereby may from time to time be increased or decreased to reflect exchanges.
Any endorsement of a Security in global form to reflect the amount, or any
increase or decrease in the amount, of Outstanding Securities represented
thereby shall be made by the Trustee in such manner and upon instructions given
by such Person or Persons as shall be specified therein or in the Company Order
to be delivered to the Trustee pursuant to Section 303 or Section 305. Subject
to the provisions of Section 303 and, if applicable, Section 305, 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 therein or in the
applicable Company Order. If a Company Order pursuant to Section 303 or Section
305 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 102 and need not be
accompanied by an Opinion of Counsel.

         The provisions of the last sentence of Section 303 shall apply to any
Security represented by a Security in global form if such Security was never
issued and sold by the



<PAGE>   29

                                       20

Company and the Company delivers to the Trustee the Security in global form
together with written instructions (which need not comply with Section 102 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 Section 308, unless otherwise
specified as contemplated by Section 301, payment of principal of (and premium,
if any) and interest, if any, on any Security in permanent global form shall be
made to the Person or Persons specified therein.

         Notwithstanding the provisions of Section 310 and except as provided in
the preceding paragraph, the Company, the Trustee and any agent of the Company
and the Trustee shall treat as the Holder of such principal amount of
Outstanding Securities represented by a permanent Global Security the Holder of
such permanent Global Security.

         SECTION 204. Form of Legend for Book-Entry Securities.

         Any Global Security authenticated and delivered hereunder shall bear a
legend (which would be in addition to any other legends required in the case of
a Restricted Security) in substantially the following form:

         THIS SECURITY IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE
     HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITORY OR A
     NOMINEE THEREOF. THIS SECURITY MAY NOT BE EXCHANGED IN WHOLE OR IN PART FOR
     A SECURITY REGISTERED, AND NO TRANSFER OF THIS SECURITY IN WHOLE OR IN PART
     MAY BE REGISTERED, IN THE NAME OF ANY PERSON OTHER THAN SUCH DEPOSITORY OR
     ITS NOMINEE EXCEPT IN THE LIMITED CIRCUMSTANCES DESCRIBED IN THE INDENTURE.





<PAGE>   30

                                       21


                                  ARTICLE THREE

                                 THE SECURITIES

         SECTION 301. Amount Unlimited; Issuable in Series.

         The aggregate principal amount of Securities which 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 one or more Board Resolutions or pursuant to authority granted by
one or more Board Resolutions and, subject to Section 303, set forth in, or
determined in the manner provided in, an Officers' Certificate, or established
in one or more indentures supplemental hereto, prior to the issuance of
Securities of any series, any or all of the following, as applicable (each of
which (except for the matters set forth in clauses (1), (2) and (9) below), if
so provided, may be determined from time to time by the Company with respect to
unissued Securities of the series and set forth in such Securities of the series
when issued from time to time):

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

         (2) The aggregate principal amount of the Securities of the series, the
     percentage of their principal amount at which the Securities of the series
     shall be issued and the date or dates on which the principal of the
     Securities of the series shall be payable or the method by which such date
     or dates shall be determined or extended;

         (3) The rate or rates (which may be fixed or variable) at which the
     Securities of the series shall bear interest, if any, and, if variable, the
     method by which such rate or rates shall be determined;

         (4) The date or dates from which any interest shall accrue or the
     method by which such date or dates will be determined, the date or dates on
     which any interest will be payable (including the Regular Record Dates for
     such Interest Payment Dates) and the basis on which any interest will be
     calculated if other than on the basis of a 360-day year of twelve 30-day
     months;

         (5) The place or places, if any, other than or in addition to New York
     City, where the principal of (and premium, if any, on) and interest, if
     any, on the Securities of the series will be payable, where any Securities
     may be surrendered for registration of transfer, where the Securities of
     the series may be surrendered for exchange and



<PAGE>   31

                                       22

     where notices or demands to or upon the Company in respect of the
     Securities of the series may be served;

         (6) The period or periods within which, the price or prices at which,
     and the other terms and conditions upon which, the Securities of the series
     may be redeemed, in whole or in part, at the option of the Company, if the
     Company is to have that option;

         (7) The obligation, if any, of the Company to redeem, purchase or repay
     the Securities of the series, in whole or in part, pursuant to any sinking
     fund or analogous provision or at the option of a holder thereof, and the
     period or periods within which, the price or prices at which, and the other
     terms and conditions upon which, the Securities of the series will be so
     redeemed, purchased or repaid;

         (8) Whether the amount of payments of principal of (and premium, if
     any, on) and interest, if any, on the Securities of the series may be
     determined with reference to an index, formula or other method (which
     index, formula or method may, without limitation, be based on one or more
     commodities, equity indices or other indices) and the manner in which such
     amounts shall be determined;

         (9) Any deletions from, modifications of or additions to the Events of
     Default or covenants of the Company with respect to the Securities of the
     series (which Events of Default or covenants may not be consistent with the
     Events of Default or covenants set forth in the general provisions of this
     Indenture);

         (10) If other than the entire principal amount thereof, the portion of
     the principal amount of the Securities of the series that shall be payable
     upon declaration of acceleration of the Maturity thereof pursuant to
     Section 502 or the method by which such portion shall be determined;

         (11) Any provisions in modification of, in addition to or in lieu of
     any provisions Article Fourteen of this Indenture that shall be applicable
     to the Securities of the series;

         (12) Any provisions granting special rights to the Holders of the
     Securities of the series upon the occurrence of such events as may be
     specified;

         (13) If other than the Trustee, the designation of any Paying Agent or
     Security Registrar for the Securities of the series, and the designation of
     any transfer or other agents or depositories for the Securities of the
     series;




<PAGE>   32

                                       23

         (14) Whether the Securities of the series shall be issuable initially
     in temporary global form, whether any the Securities of the series Security
     is to be issuable in permanent global form (a "Global Security") and, if
     so, whether beneficial owners of interests in any Global Security may
     exchange such interests for Debt Securities 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 the Indenture, and, if
     the Securities are to be issuable as a Global Security, the identity of the
     depository for the Securities of the series;

         (15) The person to whom any interest on any Security shall be payable,
     if other than the person in whose name the Securities of the series
     Security (or one or more Predecessor Securities) is registered at the close
     of business on the Regular Record Date for such interest or the manner in
     which, any interest payable on a temporary Security issued in global form
     shall be paid (if other than as described in Section 304);

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

         (17) Whether and under what circumstances the Company shall pay
     Additional Amounts, as contemplated by Section 1008 of this Indenture, on
     the Securities of the series to any Holder who is not a United States
     person (including any modification of the definition of such term as
     contained in this Indenture) in respect of any tax, assessment or
     governmental charge and, if so, whether the Company shall have the option
     to redeem the Securities of the series rather than pay such Additional
     Amounts (and the terms of any such option); and

         (18) Any other terms, conditions, rights and preferences (or
     limitations on such rights and preferences) of the Securities of the series
     not inconsistent with the provisions of this Indenture.

         All Securities of any one series shall be substantially identical
except as may otherwise be provided in or pursuant to such Board Resolution
(subject to Section 303) and set forth in such Officers' Certificate or in any
such indenture supplemental hereto. Not all Securities of any one series need be
issued at the same time, and, unless otherwise provided, a series may be
reopened for issuances of additional Securities of such series.

         If any of the terms of the series are established by action taken
pursuant to one or more Board Resolutions, such Board Resolutions shall be
delivered to the Trustee at or prior to the delivery of the Officers'
Certificate setting forth the terms of the series.




<PAGE>   33

                                       24

         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, the Securities of such series, other than Securities issued in
global form (which may be of any denomination), shall be issuable in
denominations 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 any one of
the following: its Chairman, Chief Executive Officer, its President or one of
its Vice Presidents, and attested by one of its Vice Presidents or its Corporate
Secretary or one of its Assistant Corporate 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 such Company Order shall authenticate and make available for
delivery such Securities. If not all the Securities of any series are to be
issued at one time and if the Board Resolution or supplemental indenture
establishing such series shall so permit, such Company Order may set forth
procedures acceptable to the Trustee for the issuance of such Securities and
determining terms of particular Securities of such series such as interest rate,
stated maturity, date of issuance and date from which interest shall accrue.

         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 TIA Sections 315(a)
through 315(d)) shall be fully protected in relying upon, an Opinion of Counsel
stating:

         (1) that the form or forms of such Securities have been established in
     conformity with the provisions of this Indenture;




<PAGE>   34

                                       25

         (2) that the terms of such Securities have been established in
     conformity with the provisions of this Indenture;

         (3) that such Securities, when completed by appropriate insertions and
     executed and delivered by the Company to the Trustee for authentication in
     accordance with this Indenture, authenticated and made available for
     delivery by the Trustee in accordance with this Indenture and issued by the
     Company in the manner and subject to any conditions specified in such
     Opinion of Counsel, will constitute the legal, valid and binding
     obligations of the Company, enforceable in accordance with their terms,
     subject to applicable bankruptcy, insolvency, reorganization and other
     similar laws of general applicability relating to or affecting the
     enforcement of creditors' rights, to general equitable principles and to
     such other qualifications as such counsel shall conclude do not materially
     affect the rights of Holders of such Securities and any coupons;

         (4) that all laws and requirements in respect of the execution and
     delivery by the Company of such Securities, and of the supplemental
     indentures, if any, have been complied with and that authentication and
     delivery of such Securities and the execution and delivery of the
     supplemental indenture, if any, by the Trustee will not violate the terms
     of the Indenture;

         (5) that the Company has the corporate power to issue such Securities,
     and has duly taken all necessary corporate action with respect to such
     issuance; and

         (6) that the issuance of such Securities will not contravene the
     articles of incorporation or bylaws of the Company or result in any
     violation of any of the terms or provisions of any law or regulation or of
     any indenture, mortgage or other agreement known to such Counsel by which
     the Company is bound.

         Notwithstanding the provisions of Section 301 and of the preceding two
paragraphs, if not all the Securities of any series are to be issued at one
time, it shall not be necessary to deliver the Officers' Certificate otherwise
required pursuant to Section 301 or the Company Order and Opinion of Counsel
otherwise required pursuant to the preceding two paragraphs prior to or at the
time of issuance of each Security, but such documents shall be delivered prior
to or at the time of issuance of the first Security of such series.

         The Trustee shall not be required to authenticate and make available
for delivery any 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 which is not
reasonably acceptable to the Trustee.



<PAGE>   35

                                       26

         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 duly
executed by the Trustee by manual signature of an authorized signatory, and such
certificate upon any Security shall be conclusive evidence, and the only
evidence, that such Security has been duly authenticated and delivered hereunder
and is entitled to the benefits of this Indenture. 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 311 together
with a written statement (which need not comply with Section 102 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. Book-Entry Securities.

         (a) The Securities of a series may be issuable in whole or in part in
the form of one or more Global Securities ("Book-Entry Securities") deposited
with, or on behalf of, a Depository (the "Depository"). In the case of
Book-Entry Securities, one or more Global Securities will be issued in a
denomination or aggregate denomination equal to the portion of the aggregate
principal amount of Outstanding Securities of the series to be represented by
such Global Security or Global Securities. Unless otherwise provided as
contemplated by Section 301, the additional provisions set forth in this Section
304 shall apply to Book-Entry Securities.

         (b) Book-Entry Securities will be deposited with, or on behalf of, the
Depository, and registered in the name of the Depository's nominee, for credit
to the respective accounts of institutions that have accounts with the
Depository or its nominee ("Participants"); provided that Book-Entry Securities
purchased by persons outside the United States may be credited to or through
accounts maintained at the Depository by or on behalf of Euroclear or Cedel. The
accounts to be credited will be designated by the underwriters or agents of such
Securities or, if such Securities are offered and sold directly by the Company,
by the Company. Ownership of beneficial interests in Book-Entry Securities will
be limited to Persons that may hold interests through Participants and will be
shown on records maintained by the Depository or its nominee for such Book-Entry
Security.

         Participants shall have no rights under this Indenture or any indenture
supplemental hereto with respect to any Book-Entry Security held on their behalf
by the Depository, or the Trustee as its custodian, or under the Book-Entry
Security, and the



<PAGE>   36

                                       27

Depository may be treated by the Company, the Trustee and any agent of the
Company or the Trustee as the absolute owner of the Book-Entry Security for all
purposes whatsoever. Notwithstanding the foregoing, nothing in this Indenture or
any such indenture supplemental shall prevent the Company, the Trustee or any
agent of the Company or the Trustee from giving effect to any written
certification, proxy or other authorization furnished by the Depository or
impair, as between the Depository and its Participants, the operation of
customary practices governing the exercise of the rights of a Holder of any
Security.

         (c) Transfers of Book-Entry Securities shall be limited to transfers in
whole, but not in part, to the Depository, its successors or their respective
nominees. Interests of beneficial owners in Book-Entry Securities may be
transferred or exchanged for Securities in fully registered, certificated form
("Definitive Securities") only if (i) the Depository notifies the Trustee in
writing that the Depository is no longer willing or able to continue as
depositary and a qualified successor depository is not appointed by the Company
within 90 days following such notice, (ii) the Company, at any time and in its
sole discretion, determines not to have any Debt Securities of one or more
series represented by Global Securities or (iii) after the occurrence of an
Event of Default with respect to such Debt Securities, a holder of Debt
Securities notifies the Trustee in writing that it wishes to receive a
Definitive Security. In any such instance, an owner of a beneficial interest in
a Global Security will be entitled to physical delivery of Definitive Securities
equal in principal amount to such beneficial interest and registered in its
name.

         (d) In connection with any transfer or exchange of a portion of the
beneficial interest in any Book-Entry Security to beneficial owners pursuant to
paragraph (c) above, the Security Registrar shall reflect on its books and
records the date and a decrease in the principal amount of the Book-Entry
Security in an amount equal to the principal amount of the beneficial interest
in the Book-Entry Security to be transferred, and the Company shall execute, and
the Trustee shall authenticate and deliver, one or more Definitive Securities of
like tenor and principal amount of authorized denominations.

         (e) In connection with the transfer of Book-Entry Securities as an
entirety to beneficial owners pursuant to paragraph (c) above, the Book-Entry
Securities 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 Depository in exchange for its
beneficial interest in the Book-Entry Securities, an equal aggregate principal
amount of Definitive Securities of like tenor of authorized denominations.

         (f) The Holder of any Book-Entry Security may grant proxies and
otherwise authorize any Person, including Participants and Persons that may hold
interests through Participants, to take any action which a Holder is entitled to
take under the applicable Indenture or the Securities.



<PAGE>   37

                                       28

         SECTION 305. 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 which are typewritten, printed, lithographed,
engraved or otherwise produced by any combination of these methods, 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
executing such Securities may determine, as evidenced by their execution of such
Securities. Such temporary Securities may be in global form.

         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 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.

         Until exchanged in full as hereinabove provided, the temporary
Securities of any series, including temporary Global Securities (whether or not
issued as Book-Entry Securities as provided  in Section 304), 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.


<PAGE>   38
                                       29



         SECTION 306. Registration, Registration of Transfer and Exchange.

         The Company shall cause to be kept at the Corporate Trust Office of the
Trustee a register for each series of Securities (the registers maintained in
such office of the Trustee and in any other office or agency designated pursuant
to Section 1002 being herein sometimes 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. The Trustee is hereby initially appointed "Security Registrar" for
the purpose of registering Securities and transfers of Securities as herein
provided.

         Except as otherwise described in this Article Three, upon surrender for
registration of transfer of any Security of any series at the office or agency
in a Place of Payment for that series, the Company shall execute, and the
Trustee shall authenticate and deliver, in the name of the designated transferee
or transferees, one or more new Securities of the same series, in each case, of
any authorized denominations and of a like aggregate principal amount.




<PAGE>   39
                                       30



         At the option of the Holder, Securities of any series may be exchanged
for other Securities of the same series, 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
make available for delivery, the Securities which the Holder making the exchange
is entitled to receive.

<PAGE>   40
                                       31




         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 Security Registrar) 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 pay all documentary, stamp, similar issue or transfer taxes or other
governmental charges that may be imposed in connection with any registration of
transfer or exchange of Securities, other than exchanges pursuant to Section
305, 906, 1107 or 1305 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 selection for redemption of Securities
of that series under Section 1103 or 1203 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,
or (iii) to issue, register the transfer of or exchange any Security which has
been surrendered for repayment at the option of the Holder, except the portion,
if any, of such Security not to be so repaid.

         SECTION 307. Mutilated, Destroyed, Lost and Stolen Securities.

         If any mutilated Security is surrendered to the Trustee together with,
in proper cases, such security or indemnity as may be required by the Company or
the Trustee to save each of them and any agent of either of them harmless, the
Company shall execute 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, or, in case any
such mutilated Security has become or is about to become due and payable, the
Company in its



<PAGE>   41
                                       32



discretion may, instead of issuing a new Security, pay such Security.

         If there shall be delivered to the Company and to 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 Company Order 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.

         Notwithstanding the provisions of the previous two paragraphs, 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, the Company
may require the payment of a sum sufficient to pay all documentary, stamp or
similar issue or transfer taxes or other governmental charges that may be
imposed in relation thereto and any other expenses (including the fees and
expenses of the Trustee) connected therewith.

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

         The provisions of this Section 307 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.




<PAGE>   42
                                       33



         SECTION 308. Payment of Interest; Interest Rights Preserved; Optional
Interest Reset.

         (a) Unless otherwise provided as contemplated by Section 301 with
respect to any series of Securities, interest, if any, 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 such Security (or one or more
Predecessor Securities) is registered at the close of business on the Regular
Record Date for such interest at the office or agency of the Company maintained
for such purpose pursuant to Section 1002; provided, however, that each
installment of interest, if any, on any Security may at the Company's option be
paid by (i) mailing a check for such interest, payable to or upon the written
order of the Person entitled thereto pursuant to Section 310, to the address of
such Person as it appears on the Security Register or (ii) wire transfer to an
account located in the United States maintained by the payee.

         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 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 and, if
applicable, interest on such defaulted interest (to the extent lawful) at the
rate specified in the Securities of such series (such defaulted interest and, if
applicable, interest thereon herein collectively called "Defaulted Interest")
may be paid by the Company, at its election in each case, as provided in
Subsection (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 (except as otherwise specified pursuant to Section 301 for the
     Securities of such series) 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 on or prior to the date of the
     proposed payment, such money when deposited to



<PAGE>   43
                                       34



     be held in trust for the benefit of the Persons entitled to such Defaulted
     Interest as in this Subsection 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 given in the
     manner provided in Section 106, not less than 10 days prior to such Special
     Record Date. Notice of the proposed payment of such Defaulted Interest and
     the Special Record Date therefor having been so given, such Defaulted
     Interest shall be paid to the Persons in whose name 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 Subsection (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, such manner of payment shall be deemed practicable by the
     Trustee.

         (b) The provisions of this Section 308(b) may be made applicable to any
series of Securities pursuant to Section 301 (with such modifications, additions
or substitutions as may be specified pursuant to such Section 301). The interest
rate (or the spread or spread multiplier used to calculate such interest rate,
if applicable) on any Security of such series may be reset by the Company on the
date or dates specified on the face of such Security (each an "Optional Reset
Date"). The Company may exercise such option with respect to such Security by
notifying the Trustee of such exercise at least 50 but not more than 60 days
prior to an Optional Reset Date for such Note, which such notice shall contain
such information as may be required by the Trustee to transmit the Reset Notice
as hereinafter defined). Not later than 40 days prior to each Optional Reset
Date, the Trustee shall transmit, in the manner provided for in Section 106, to
the Holder of any such Security a notice (the "Reset Notice") indicating whether
the Company has elected to reset the interest rate (or the spread or spread
multiplier used to calculate such interest rate, if applicable), and if so (i)
such new interest rate (or such new spread or spread multiplier, if applicable)
and (ii) the provisions, if any, for redemption during the period from such
Optional Reset Date to the next Optional Reset Date or if there is no such next
Optional Reset Date, to the Stated Maturity Date of such Security (each such
period a "Subsequent Interest Period"), including the date or dates on which or
the period or periods during which and the price or prices at which such
redemption may occur during the Subsequent Interest Period.



<PAGE>   44
                                       35


         Notwithstanding the foregoing, not later than 20 days prior to the
Optional Reset Date, the Company may, at its option, revoke the interest rate
(or the spread or spread multiplier used to calculate such interest rate, if
applicable) provided for in the Reset Notice and establish an interest rate (or
a spread or spread multiplier used to calculate such interest rate, if
applicable) that is higher than the interest rate (or the spread or spread
multiplier, if applicable) provided for in the Reset Notice, for the Subsequent
Interest Period by causing the Trustee to transmit, in the manner provided for
in Section 106, notice of such higher interest rate (or such higher spread or
spread multiplier, if applicable) to the Holder of such Security. Such notice
shall be irrevocable. All Securities with respect to which the interest rate (or
the spread or spread multiplier used to calculate such interest rate, if
applicable) is reset on an Optional Reset Date, and with respect to which the
Holders of such Securities have not tendered such Securities for repayment (or
have validly revoked any such tender) pursuant to the next succeeding paragraph,
will bear such higher interest rate (or such higher spread or spread multiplier,
if applicable).

         The Holder of any such Security will have the option to elect repayment
by the Company of the principal of such Security on each Optional Reset Date at
a price equal to the principal amount thereof plus interest accrued to such
Optional Reset Date. In order to obtain repayment on an Optional Reset Date, the
Holder must follow the procedures set forth in Article Thirteen for repayment at
the option of Holders except that the period for delivery or notification to the
Trustee shall be at least 25 but not more than 35 days prior to such Optional
Reset Date and except that, if the Holder has tendered any Security for
repayment pursuant to the Reset Notice, the Holder may, by written notice to the
Trustee, revoke such tender or repayment until the close of business on the
tenth day before such Optional Reset Date.

         Subject to the foregoing provisions of this Section and Section 306,
each Security delivered under this Indenture upon registration of transfer of or
in exchange for or in lieu of any other Security shall carry the rights to
interest accrued and unpaid, and to accrue, which were carried by such other
Security.

         SECTION 309. Optional Extension of Stated Maturity.

         The provisions of this Section 309 may be made applicable to any series
of Securities pursuant to Section 301 (with such modifications, additions or
substitutions as may be specified pursuant to such Section 301). The Stated
Maturity of any Security of such series may be extended at the option of the
Company for the period or periods specified on the face of such Security (each
an "Extension Period") up to but not beyond the date (the "Final Maturity") set
forth on the face of such Security. The Company may exercise such option with
respect to any Security by notifying the Trustee of such exercise at least 50
but not more than 60 days prior to the Stated Maturity of such Security in
effect prior to the exercise of such option (the "Original Stated Maturity"). If
the Company exercises such option, the Trustee



<PAGE>   45
                                       36


shall transmit, in the manner provided for in Section 106, to the Holder of such
Security not later than 40 days prior to the Original Stated Maturity a notice
(the "Extension Notice") indicating (i) the election of the Company to extend
the Stated Maturity, (ii) the new Stated Maturity, (iii) the interest rate, if
any, applicable to the Extension Period and (iv) the provisions, if any, for
redemption during such Extension Period. Upon the Trustee's transmittal of the
Extension Notice, the Stated Maturity of such Security shall be extended
automatically and, except as modified by the Extension Notice and as described
in the next paragraph, such Security will have the same terms as prior to the
transmittal of such Extension Notice.

         Notwithstanding the foregoing, not later than 20 days before the
Original Stated Maturity of such Security, the Company may, at its option,
revoke the interest rate provided for in the Extension Notice and establish a
higher interest rate for the Extension Period by causing the Trustee to
transmit, in the manner provided for in Section 106, notice of such higher
interest rate to the Holder of such Security. Such notice shall be irrevocable.
All Securities with respect to which the Stated Maturity is extended will bear
such higher interest rate.

         If the Company extends the Maturity of any Security, the Holder will
have the option to elect repayment of such Security by the Company on the
Original Stated Maturity at a price equal to the principal amount thereof, plus
interest accrued to such date. In order to obtain repayment on the Original
Stated Maturity once the Company has extended the Maturity thereof, the Holder
must follow the procedures set forth in Article Thirteen for repayment at the
option of Holders, except that the period for delivery or notification to the
Trustee shall be at least 25 but not more than 35 days prior to the Original
Stated Maturity and except that, if the Holder has tendered any Security for
repayment pursuant to an Extension Notice, the Holder may by written notice to
the Trustee revoke such tender for repayment until the close of business on the
tenth day before the Original Stated Maturity.

         SECTION 310. Persons Deemed Owners.

         Prior to due presentment of a Security for registration of transfer,
the Company, the Trustee and any agent of the Company or the Trustee may treat
the Person in whose name such Security is registered as the owner of such
Security for the purpose of receiving payment of principal of (and premium, if
any) and (subject to Sections 306 and 308) interest, if any, on such Security
and for all other purposes whatsoever, whether or not such Security be overdue,
and none of the Company, the Trustee or any agent of the Company or the Trustee
shall be affected by notice to the contrary.

         None of the Company, the Trustee, any Paying Agent or the Security
Registrar will have any responsibility or liability for any aspect of the
records relating to or payments



<PAGE>   46
                                       37


made on account of beneficial ownership interests of a Security in global form
or for maintaining, supervising or reviewing any records relating to such
beneficial ownership interests.

         Notwithstanding the foregoing, with respect to any Global Security,
nothing herein shall prevent the Company, the Trustee, or any agent of the
Company or the Trustee, from giving effect to any written certification, proxy
or other authorization furnished by any Depositary, as a Holder, with respect to
such Global Security or impair, as between such Depositary and owners of
beneficial interests in such Global Security, the operation of customary
practices governing the exercise of the rights of such depositary (or its
nominee) as Holder of such Global Security.

         SECTION 311. Cancellation.

         All Securities surrendered for payment, redemption, repayment at the
option of the Holder, registration of transfer or exchange or for credit against
any current or future sinking fund payment shall, if surrendered to any Person
other than the Trustee, be delivered to the Trustee. All Securities so delivered
to the Trustee shall be promptly cancelled by it. 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 may deliver to the Trustee (or to any other Person for delivery
to the Trustee) for cancellation any Securities previously authenticated
hereunder which the Company has not issued and sold, and all Securities so
delivered shall be promptly cancelled by the Trustee. If the Company shall so
acquire any of the Securities, however, such acquisition shall not operate as a
redemption or satisfaction of the indebtedness represented by such Securities
unless and until the same are surrendered to the Trustee for cancellation. No
Securities shall be authenticated in lieu of or in exchange for any Securities
cancelled as provided in this Section, except as expressly permitted by this
Indenture. All cancelled Securities held by the Trustee shall be disposed of by
the Trustee in accordance with its customary procedures, unless by Company Order
the Company shall direct that cancelled Securities be returned to it.

         SECTION 312. Computation of Interest.

         Except as otherwise specified as contemplated by Section 301 with
respect to any Securities, interest, if any, on the Securities of each series
shall be computed on the basis of a 360-day year of twelve 30-day months.





<PAGE>   47
                                       38


         SECTION 313. CUSIP Numbers.

         The Company in issuing the Securities may use "CUSIP" numbers (if then
generally in use) in addition to serial numbers, and, if so, the Trustee shall
use such "CUSIP" numbers in addition to serial numbers in notices of repurchase
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 repurchase and that
reliance may be placed only on the serial or other identification numbers
printed on the Securities, and any such repurchase shall not be affected by any
defect in or omission of such "CUSIP" numbers. The Company will promptly notify
the Trustee of any change in the "CUSIP" 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 any series of Securities specified in such Company
Request (except as to any surviving rights of registration of transfer or
exchange of Securities of such series expressly provided for herein or pursuant
hereto) and the Trustee, on demand of and at the expense of the Company, shall
execute proper instruments acknowledging satisfaction and discharge of this
Indenture as to such series when

         (1) either

             (A) all Securities of such series theretofore authenticated and
         delivered have been delivered to the Trustee for cancellation; or

             (B) all Securities of such series not theretofore delivered to the
         Trustee for cancellation

                 (i) have become due and payable, or

                 (ii) will become due and payable at their Stated Maturity
             within one year, or

                 (iii) if redeemable at the option of the Company, are to be
             called for redemption within one year under arrangements
             satisfactory to



<PAGE>   48
                                       39


             the Trustee for the giving of notice of redemption by the Trustee
             in the name, and at the expense, of the Company,

         and the Company, in the case of (i), (ii) or (iii) above, has
         irrevocably deposited or caused to be deposited with the Trustee as
         trust funds in trust for such purpose an amount sufficient to pay and
         discharge the entire indebtedness on such Securities not theretofore
         delivered to the Trustee for cancellation, for principal (and premium,
         if any) and interest, if any, to the date of such deposit (in the case
         of Securities which have become due and payable) or to the Stated
         Maturity or Redemption Date, as the case may be;

         (2) the Company has paid or caused to be paid all other sums payable
     hereunder by the Company; and

         (3) 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 as to such series have been complied with.

         Notwithstanding the satisfaction and discharge of this Indenture, the
obligations of the Company to the Trustee under Section 606, the obligations of
the Trustee to any Authenticating Agent under Section 612 and, if money shall
have been deposited with the Trustee pursuant to subclause (B) of Subsection (1)
of this Section, the obligations of the Trustee under Section 402 and the last
paragraph of Section 1003 shall survive.

         SECTION 402. Application of Trust Money.

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





<PAGE>   49
                                       40


                                  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:

         (1) default in the payment of any installment of interest upon any
     Security of such series when it becomes due and payable, continued for 30
     days; or

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

         (3) failure on the part of the Company to observe or perform any other
     covenant or agreement contained in this Indenture (other than a covenant or
     agreement included in this Indenture solely for the benefit of less than
     all series of Securities or a covenant the default in the performance of
     which would be covered by clause (7) below) for 60 days after written
     notice of such failure, requiring the Company to remedy the same, has been
     given 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 outstanding
     Securities of such series; or

         (4) default under any indenture or instrument under which the Company
     or any Restricted Subsidiary has at the time outstanding indebtedness for
     borrowed money or guarantees thereof in any individual instance in excess
     of $15,000,000 and, if not already matured in accordance with its terms,
     such indebtedness has been accelerated and such acceleration is not
     rescinded or annulled within 15 days after notice thereof has been given 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 outstanding Securities of
     such series; provided that, if, prior to the entry of judgment in favor of
     the Trustee for payment of the Indenture Securities of such series, the
     default under such indenture or instrument has been remedied or cured by
     the Company or such Restricted Subsidiary, or waived by the holders of such
     indebtedness, then the Event of Default under the Indenture will be deemed
     likewise to have been remedied, cured or waived; or

         (5) the entry of a decree or order by court having jurisdiction in the
     premises adjudging the Company a bankrupt or insolvent, or approving as
     properly filed a petition seeking reorganization, arrangement, adjustment
     or composition of or in



<PAGE>   50
                                       41


     respect of the Company under the Bankruptcy Code or any other applicable
     federal or state law, or appointing a receiver, liquidator, assignee,
     trustee, sequestrator (or other similar official) of the Company or of any
     substantial part of the property of the Company, or ordering the winding up
     or liquidation of the affairs of the Company, and the continuance of any
     such decree or order unstayed and in effect for a period of 90 consecutive
     days; or

         (6) the institution by the Company of proceedings to be adjudicated a
     bankrupt or insolvent, or the consent by the Company to the institution of
     bankruptcy or insolvency proceedings against it, or the filing by the
     Company of a petition or answer or consent seeking reorganization or relief
     under the Bankruptcy Code or any other applicable federal or state law, or
     the consent by the Company to the filing of any such petition or to the
     appointment of a receiver, liquidator, assignee, trustee, sequestrator (or
     other similar official) of the Company or of any substantial part of the
     property of the Company of an assignment for the benefit of creditors, or
     the admission by the Company in writing of its inability to pay its debts
     generally as they become due; or

         (7) any other Event of Default provided for the benefit of Securities
     of such series.

         SECTION 502. Acceleration of Maturity; Rescission and Annulment.

         If any Event of Default described in Section 501 with respect to
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 that series may declare the principal
amount (or, if the Securities of that series are Original Issue Discount
Securities or Indexed Securities, such portion of the principal amount as may be
specified in the terms of that series) of all of the Securities of that series
and all accrued interest thereon 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 principal amount (or specified portion thereof) shall
become immediately due and payable.

         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 in this Article provided, 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

         (a) the Company has paid or deposited with the Trustee a sum sufficient
         to pay (except as otherwise specified pursuant to Section 301 for the
         Securities of such series);



<PAGE>   51
                                       42


             (1) all overdue interest, if any, on all Outstanding Securities of
             that series (or of all series, as the case may be),

             (2) all unpaid principal of (and premium, if any, on) any
             Outstanding Securities of that series (or of all series, as the
             case may be) which has become due otherwise than by such
             declaration of acceleration, and interest on such unpaid principal
             (and premium, if any) at the rate or rates prescribed therefor in
             such Securities,

             (3) interest upon such overdue interest at the rate or rates
             prescribed therefor in such Securities, and

             (4) all sums paid or advanced by the Trustee for such series
             hereunder and reasonable compensation, expenses, disbursements and
             advances of such Trustee, its agents and counsel;

         (b) all Events of Default with respect to Securities of that series (or
         of all series, as the case may be), other than the non-payment of
         principal of (or premium, if any, on) or interest, if any, on
         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 interest on any Security when
     such interest becomes due and payable and such default continues for a
     period of 30 days, or

         (2) default is made in the payment of the principal of (or premium, if
     any, on) any Security at the Maturity thereof,

then 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 (and premium, if any) and interest, if any, and
interest on any overdue principal (and premium, if any) and on any overdue
interest, at the rate or rates prescribed therefor in such Securities, and, in
addition thereto, such further amount as shall be sufficient



<PAGE>   52
                                       43


to cover the costs and expenses of collection, including the reasonable
compensation, expenses, disbursements and advances of the Trustee, its agents
and counsel.

         If the Company fails to pay such amounts forthwith upon such demand,
the Trustee, in its own name 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 (or of
all series, as the case may be) 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 (or of all series, as the case may be)
under this Indenture by such appropriate judicial proceedings as the Trustee
shall deem most effectual to protect and enforce such rights.

         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 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, premium, if any, or interest)
shall be entitled and empowered, by intervention in such proceeding or
otherwise,

         (i) to file and prove a claim for the whole amount of principal (and
     premium, if any), or such portion of the principal amount of any series of
     Original Issue Discount Securities or Indexed Securities as may be
     specified in the terms of such series, and interest, if any, owing and
     unpaid in respect of the Securities and to file such other papers or
     documents as may be necessary or advisable in order 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 moneys or other property payable or
     deliverable on any such claims and to distribute the same;




<PAGE>   53
                                       44


         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 606.

         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 proposal,
plan of reorganization, arrangement, adjustment or composition or other similar
arrangement 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
proceeding.

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

         All rights of action and claims under this Indenture or the Securities
may be prosecuted and enforced by the Trustee without the possession of any of
the Securities or the production thereof in any proceeding relating thereto, and
any such proceeding instituted by the Trustee shall be brought in its own name
and as trustee of an express trust, and any recovery of judgment shall, after
provision for the payment of the reasonable compensation, expenses,
disbursements and advances of the Trustee, its agents and counsel, 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 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 (or premium,
if any) or interest, if any, 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 606;

         Second: To the payment of the amounts then due and unpaid for principal
     of (and premium, if any) and interest, if any, on the 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 (and premium, if
     any) and interest, if any, respectively; and



<PAGE>   54
                                       45


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

         SECTION 507. Limitation on Suits.

         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) such Holder has previously given written notice to the Trustee of a
     continuing Event of Default with respect to the Securities of that series;

         (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 an Event of Default
     described in Section 501 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 or
     more 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
Holders of Securities of the same series, in respect of any Event of Default
described in Section 501, 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 Holders of Securities of the same series, in respect of such
Event of Default.

         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 (and premium, if any) and (subject to
Section 308) interest, if any, on, such



<PAGE>   55
                                       46


Security on the respective Stated 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, and such rights shall not be impaired without
the consent of such Holder.

         SECTION 509. Restoration of Rights and Remedies.

         If the Trustee or any Holder 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 in Section 307, no right or remedy herein
conferred upon or reserved to the Trustee or to the Holders of Securities 
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 Security 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 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 the Securities of any series, the Holders of not less
than 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, related to or arising under Section 501,
provided that in each case



<PAGE>   56
                                       47


         (1) such direction shall not be in conflict with any rule of law or
     with this Indenture or expose the Trustee to personal liability, and

         (2) subject to the provisions of the TIA Section 315, 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 Section 502, the Holders of not less than 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 or Event
of Default in Section 501 and its consequences, except a Default or Event of
Default,

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

         (2) in respect of a covenant or provision hereof which under Article
     Nine cannot be modified or amended without the consent of the Holder of
     each Outstanding Security of such series 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 Event of Default or impair any right consequent thereon.

         SECTION 514. Undertaking for Costs.

         All parties to this Indenture agree, and each Holder of Securities of
any series by his acceptance thereof shall be deemed to have agreed, that any
court may in its discretion require, in any suit for the enforcement of any
right or remedy under this Indenture, or in any suit against the Trustee for any
action taken, suffered 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 and expenses, 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; but the provisions of this Section shall not apply to any suit
instituted by the Trustee, to any suit instituted 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 to any suit instituted by any Holder
for the enforcement of the payment of the principal of (or premium, if any) or
interest on Securities of any series on or after the respective Stated
Maturities expressed in such Security (or, in the case of redemption,



<PAGE>   57
                                       48


on or after the Redemption Date); provided that neither this Section 514 nor the
Trust Indenture Act shall be deemed to authorize any court to require such an
undertaking or to make such an assessment in any suit instituted by the Company.

         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, extension or usury 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. Notice of Defaults.

         Within 90 days after the occurrence of any Default hereunder with
respect to the Securities of any series, the Trustee shall transmit by mail to
all Holders, as their names and addresses appear in the Security Register,
notice of such default hereunder known to the Trustee, unless such Default shall
have been cured or waived; provided, however, that, except in the case of a
default in the payment of the principal of (or premium, if any) or interest, if
any, on 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 and/or Responsible
Officers of the Trustee in good faith determines 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 breach of the character
specified in Section 501(3) with respect to Securities of such series, no such
notice to Holders shall be given until at least 30 days after the occurrence
thereof.




<PAGE>   58
                                       49


         SECTION 602. Certain Rights of Trustee.

         Subject to the provisions of TIA Sections 315(a) through 315(d):

         (1) the Trustee may conclusively 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, 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;

         (2) 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;

         (3) 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;

         (4) the Trustee may consult with counsel of its selection and the
     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;

         (5) 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 of Securities of any series pursuant to this
     Indenture, unless such Holders shall have offered to the Trustee reasonable
     security or indemnity against the costs, expenses and liabilities which
     might be incurred by it in compliance with such request or direction;

         (6) 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, 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;




<PAGE>   59
                                       50


         (7) 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 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; and

         (8) 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.

         SECTION 603. Trustee Not Responsible for Recitals or Issuance of
Securities.

         The recitals contained herein and in the Securities, except for the
Trustee's certificates of authentication, shall be taken as the statements of
the Company, and neither the Trustee nor any Authenticating Agent assumes any
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, except that the Trustee represents that it is duly
authorized to execute and deliver this Indenture, authenticate the Securities
and perform its obligations hereunder and that the statements to be made by it
in a Statement of Eligibility on Form T-1 supplied to the Company are true and
accurate, subject to the qualifications set forth therein. Neither the Trustee
nor any Authenticating Agent shall be accountable for the use or application by
the Company of Securities or the proceeds thereof.

         SECTION 604. May Hold Securities.

         The Trustee, any Authenticating Agent, any Paying Agent, any Security
Registrar or any other agent of the Company or of the Trustee, in its individual
or any other capacity, may become the owner or pledgee of Securities and,
subject to TIA Sections 310(b) and 311, 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 605. 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.




<PAGE>   60
                                       51


         SECTION 606. Compensation and Reimbursement.

         The Company agrees:

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

         (2) except as otherwise expressly provided herein, to reimburse the
     Trustee upon its request for all reasonable expenses, disbursements and
     advances incurred or made by the Trustee in accordance with any provision
     of this Indenture (including the reasonable compensation and the 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 each of Trustee or any predecessor Trustee for, and to
     hold it harmless against, any and all loss, damage, claim, liability or
     expense including taxes (other than taxes based on the income of the
     Trustee) incurred without negligence or bad faith on its part, arising out
     of or in connection with the acceptance or administration of this trust,
     including the costs and expenses of defending itself against any claim or
     liability in connection with the exercise or performance of any of its
     powers or duties hereunder.

         As security for the performance of the obligations of the Company under
this Section 606, the Trustee shall have a lien prior to the Securities upon all
property and funds held or collected by the Trustee as such, except funds held
in trust for the payment of principal of (or premium, if any) or interest, if
any, on particular Securities.

         The provisions of this Section shall survive the termination of this
Indenture.

         SECTION 607. Conflicting Interests. The Trustee shall comply with the
provisions of Section 310(b) of the Trust Indenture Act.



<PAGE>   61
                                       52


         SECTION 608. Corporate Trustee Required; Eligibility; Conflicting
Interests.

         There shall at all times be a Trustee hereunder qualified or to be
qualified under TIA Section 310(a)(1) and which, to the extent there is such an
institution eligible and willing to serve, shall have a combined capital and
surplus of at least $50,000,000. If such Trustee publishes reports of condition
at least annually, pursuant to law or to the requirements of federal, state,
territorial or District of Columbia supervising or examining authority, then for
the purposes of this Section 608, the combined capital and surplus of the
Trustee shall be deemed to be its combined capital and surplus as set forth in
its most recent report of condition so published. If at any time the Trustee
shall cease to be eligible in accordance with the provisions of this Section
608, it shall resign immediately in the manner and with the effect hereinafter
specified in this Article.

         SECTION 609. 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 shall become effective until the
acceptance of appointment by the successor Trustee under Section 610.

         (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 610 shall
not have been delivered to the Trustee within 30 days after the giving of such
notice of resignation, the resigning Trustee may, at the expense of the Company,
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 not less than a majority in
principal amount of the Outstanding Securities of such series, delivered to the
Trustee and the Company. If an instrument of acceptance by a successor Trustee
shall not have been delivered to the Trustee within 30 days after the giving of
such notice of removal, the removed Trustee may, at the expense of the Company,
petition a court of competent jurisdiction for the appointment of a successor
Trustee.

         (d) If at any time:

         (1) the Trustee shall fail to comply with the provisions of TIA Section
     310(b) 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




<PAGE>   62
                                       53


         (2) the Trustee shall cease to be eligible under Section 608 and shall
     fail to resign 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

         (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 TIA Section 514, the
Holder of any Security 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). If, within one year after
such resignation, removal or incapability, or the occurrence of such vacancy, a
successor Trustee with respect to the Securities of any series shall be
appointed by Act of the Holders of a majority in principal amount of the
Outstanding Securities of such series delivered to the Company and the retiring
Trustee, the successor Trustee so appointed shall, forthwith upon its acceptance
of such appointment in accordance with Section 610, become the successor Trustee
with respect to the Securities of such series and to that extent supersede the
successor Trustee appointed by the Company. If no successor Trustee with respect
to the Securities of any series shall have been so appointed by the Company or
the Holders and accepted appointment in the manner hereinafter provided, any
Holder who has been a bona fide Holder of a Security of such series for at least
six months may, on behalf of himself and all others similarly situated, petition
any court of competent jurisdiction for the appointment of a successor Trustee
with respect to the Securities of such series.

         (f) The Company shall give notice of each resignation and each removal
of the Trustee with respect to the Securities of any series and each appointment
of a successor Trustee with respect to the Securities of any series to the
Holders of Securities of such series in the manner provided for in Section 106.
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.



<PAGE>   63
                                       54


         SECTION 610. Acceptance of Appointment by Successor.

         (a) Every successor Trustee appointed hereunder 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; provided, however, that the
retiring Trustee shall continue to be entitled to the benefit of Section 606;
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. Whenever there is a successor Trustee with
respect to one or more (but less than all) series of securities issued pursuant
to this Indenture, the terms "Indenture" and "Securities"



<PAGE>   64
                                       55


shall have the meanings specified in the provisos to the respective definitions
of those terms in Section 101 which contemplate such situation.

         (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 rights, powers and trusts referred to
in paragraph (a) or (b) of this Section, 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.

         SECTION 611. 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 of 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, 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. In
case any of the Securities shall not have been authenticated by such predecessor
Trustee, any successor Trustee may authenticate such Securities either in the
name of any predecessor hereunder or in the name of the successor Trustee. In
all such cases such certificates shall have the full force and effect which this
Indenture provides for the certificate of authentication of the Trustee;
provided, however, that the right to adopt the certificate of authentication of
any predecessor Trustee or to authenticate Securities in the name of any
predecessor Trustee shall apply only to its successor or successors by merger,
conversion or consolidation.

         SECTION 612. Appointment of Authenticating Agent.

         At any time when any of the Securities remain Outstanding, the Trustee
may appoint an Authenticating Agent or Agents with respect to one or more series
of Securities which shall be authorized to act on behalf of the Trustee to
authenticate Securities of such series and the Trustee shall give written notice
of such appointment to all Holders of Securities of the series with respect to
which such Authenticating Agent will serve, in the manner provided for in
Section 106. 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. Any such appointment shall be evidenced
by an instrument in writing signed by an



<PAGE>   65
                                       56


Authorized Officer of the Trustee, and a copy of such instrument shall be
promptly furnished to the Company. 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, authorized under such laws to act as Authenticating Agent,
having a combined capital and surplus of not less than $50,000,000 and subject
to supervision or examination by federal or state 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, the combined capital and surplus of such corporation shall be
deemed to be its combined capital and surplus as set forth in its most recent
report of condition so published. If at any time an Authenticating Agent shall
cease to be eligible in accordance with the provisions of this Section, it shall
resign immediately in the manner and with the effect specified in this Section.

         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, 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, the Trustee may appoint a successor Authenticating
Agent which shall be acceptable to the Company and shall give written notice of
such appointment to all Holders of Securities of the series with respect to
which such Authenticating Agent will serve, in the manner provided for in
Section 106. 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.

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



<PAGE>   66
                                       57


         If an appointment with respect to one or more series is made pursuant
to this Section, the Securities of such series may have endorsed thereon, in
addition to the Trustee's certificate of authentication, an alternate
certificate of authentication in the following form:

         Dated: ____________________

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

                                 U.S. BANK TRUST NATIONAL ASSOCIATION,
                                                    as Trustee

                                 By
                                   -----------------------------------------
                                   as Authenticating Agent

                                 By
                                   -----------------------------------------
                                   Authorized Officer


         SECTION 613. Preferential Collection of Claims Against Company.

         If and when the Trustee shall be or become a creditor of the Company
(or any other obligor under the Securities), the Trustee shall be subject to the
provisions of the Trust Indenture Act regarding the collection of claims against
the Company (or any such other obligor).


                                  ARTICLE SEVEN

                HOLDERS' LISTS AND REPORTS BY TRUSTEE AND COMPANY

         SECTION 701. Disclosure of Names and Addresses of Holders.

         Every Holder of Securities by receiving and holding the same, agrees
with the Company and the Trustee that none of the Company or the Trustee or any
agent of either of them shall be held accountable by reason of the disclosure of
any information as to the names and addresses of the Holders in accordance with
TIA Section 312, regardless of the source from which such information was
derived, and that the Trustee shall not be held accountable by reason of mailing
any material pursuant to a request made under TIA Section 312.



<PAGE>   67
                                       58


         SECTION 702. Reports by Trustee.

         Within 60 days after April 1 of each year commencing with the first
April 1 after the first issuance of Securities pursuant to this Indenture, the
Trustee shall transmit to the Holders of Securities, in the manner and to the
extent provided in TIA Section 313(c), a brief report dated as of such April 1
if required by TIA Section 313(a).

         SECTION 703. Reports by Company.

         The Company shall:

         (1) file with the Trustee, within 30 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 Exchange Act; or,
     if the Company is not required to file information, documents or reports
     pursuant to either of such Sections, then it shall file with the Trustee
     and the Commission, in accordance with rules and regulations prescribed
     from time to time by the Commission, such of the supplementary and periodic
     information, documents and reports which may be required pursuant to
     Section 13 of the Exchange Act in respect of a security listed and
     registered on a national securities exchange as may be prescribed from time
     to time in such rules and regulations;

         (2) file with the Trustee and the Commission, in accordance with rules
     and regulations prescribed from time to time by the Commission, such
     additional information, documents and reports with respect to compliance by
     the Company with the conditions and covenants of this Indenture as may be
     required from time to time by such rules and regulations; and

         (3) transmit by mail to all Holders, as their names and addresses
     appear in the Security Register, within 30 days after the filing thereof
     with the Trustee, in the manner and to the extent provided in TIA Section
     313(c), such summaries of any information, documents and reports required
     to be filed by the Company pursuant to Subsections (1) and (2) of this
     Section as may be required by rules and regulations prescribed from time to
     time by the Commission.





<PAGE>   68
                                       59


                                  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, or sell,
assign, transfer, lease, convey or otherwise dispose of all or substantially all
of its assets to, any Person, unless:

         (1) Immediately after giving effect to such transaction, no Event of
     Default (or event that with notice or lapse of time, or both, would become
     an Event of Default) shall have happened and be continuing;

         (2) The corporation or other entity formed by such consolidation or
     into which the Company is merged, or the Person to which such properties
     and assets will have been conveyed, transferred or leased, assumes the
     Company's obligation as to the due and punctual payment of the principal of
     (and premium, if any, on) and interest, if any, on all the Securities and
     the performance and observance of every covenant to be performed by the
     Company under the Indenture, and will be organized under the laws of the
     United States, one of the states thereof or the District of Columbia; and

         (3) The Company has delivered to the Trustee an Officers' Certificate
     and Opinion of Counsel, each stating that such consolidation, merger,
     conveyance, transfer or lease and such supplemental indenture comply with
     this Article and that all conditions precedent herein provided for relating
     to such transaction have been complied with.

             This Section shall only apply to a merger or consolidation in which
     the Company is not the surviving corporation and to conveyances, leases and
     transfers by the Company as transferor or lessor.

         SECTION 802. Rights and Duties of Successor Corporation.

         In case of any such consolidation, merger, conveyance or transfer to
which Section 801 applies and upon any such assumption by the successor
corporation or Person, such successor corporation or Person shall succeed to and
be substituted for the Company with the same effect as if it had been named
herein as the Company and the predecessor corporation shall be relieved of any
further obligation under this Indenture. Such successor corporation or Person
thereupon may cause to be signed, and may issue either in its own name or in the
name of the Company any or all of the Securities issuable hereunder which



<PAGE>   69
                                       60


theretofore shall not have been signed by the Company and delivered to the
Trustee; and, upon the order of such successor corporation or Person, instead of
the Company, and subject to all the terms, conditions and limitations in this
Indenture prescribed, the Trustee shall authenticate and shall deliver any
Securities which previously shall have been signed and delivered by the officers
of the Company to the Trustee for authentication, and any Securities which such
successor corporation or Person thereafter shall cause to be signed and
delivered to the Trustee for that purpose. All the Securities so issued shall in
all respects have the same legal rank and benefit under this Indenture as the
Securities theretofore or thereafter issued in accordance with the terms of this
Indenture as though all of such Securities had been issued at the date of the
execution hereof. As used in this Section, "successor corporation or Person"
means the corporation formed by such consolidation or into which the Company is
merged, or the Person which acquires by conveyance, transfer or lease the
properties and assets of the Company substantially as an entirety, as the case
may be, in each case as provided in Section 801.

         SECTION 803. Securities to be Secured in Certain Events.

         If, upon any such consolidation of the Company with, or merger of the
Company , into, any other corporation, or upon any conveyance, transfer or
lease of the property of the Company substantially as the entirety to any other
Person, any Principal Property of the Company or any Restricted Securities
owned immediately prior thereto, would become or be subject to any Lien, then
unless such Lien could be created pursuant to Section 1006 without equally and
ratably securing the Securities, the Company prior to or simultaneously with
such transaction will, as to such Principal Property or Restricted Securities,
secure the Securities Outstanding hereunder (together with, if the Company
shall so determine, any other Debt of the Company now existing or hereafter
created which is not subordinate to the Securities) equally and ratably with
(or prior to) the Debt which upon such is to become secured as to such
Principal Property or Restricted Securities by such Lien, or will cause such
Securities to be so secured; provided that for the purpose of providing such
equal and ratable security the principal amount of Original Issue Discount
Securities and Indexed Securities shall mean that amount which, at the time of
making such provision of such equal and ratable security, would be due and
payable pursuant to Section 502 and the terms of such Original Issue Discount
Securities and Indexed Securities upon a declaration of acceleration of the
Maturity thereof, and the extent of such equal and ratable security shall be
adjusted, to the extent permitted by law, as and when said amount changes over
time pursuant to the terms of such Original Issue Discount Securities and
Indexed Securities.





<PAGE>   70
                                       61


                                  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 being included solely for the benefit of such series) or to
     surrender any right or power herein or in the Securities conferred upon the
     Company; or

         (3) to add any additional Events of Default (and if such Events of
     Default are to be for the benefit of less than all series of Securities,
     stating that such Events of Default are being included solely for the
     benefit of such series); 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 entitled to the benefit
     of such provision; or

         (5) to secure the Securities pursuant to the requirements of Section
     803 or 1006 or otherwise; or

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

         (7) 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
     610(b); or



<PAGE>   71
                                       62


         (8) to close this Indenture with respect to the authentication and
     delivery of additional series of Securities; 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 that such action shall not
     adversely affect the interests of the Holders of Securities of any series
     in any material respect; or

         (10) 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 Sections 401, 1402 and
     1403; provided that any such action shall not adversely affect the
     interests of the Holders of Securities of such series or any other series
     of Securities in any material respect; or

         (11) to make any other change that does not adversely affect the rights
     of any Holder.

         SECTION 902. Supplemental Indentures with Consent of Holders.

         With the consent of the Holders of not less than a majority in
principal amount of all Outstanding Securities affected by such supplemental
indenture, by Act of such Holders delivered to the Company and the Trustee, the
Company, when authorized by a Board Resolution, and the Trustee may enter into
one or more 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 under this Indenture; provided, however, that no such supplemental
indenture amendment or waiver shall, without the consent of the Holder of each
Outstanding Security affected thereby:

         (1) change the Stated Maturity of the principal of (or premium, if any)
     or any installment of interest on any Security, or reduce the principal
     amount thereof (or premium, if any) or the rate of interest, if any,
     thereon, or change any obligation of the Company to pay Additional Amounts
     as contemplated by Section 1008 (except as contemplated by Section 801(2)
     and permitted by Section 901(1)), or reduce the amount of the principal of
     an Indexed Security or 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 the amount thereof provable in bankruptcy
     pursuant to Section 504, or adversely affect any



<PAGE>   72
                                       63


     right of repayment at the option of any Holder of any Security, or change
     any Place of Payment where, any Security or any premium or interest thereon
     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 or repayment at the option of the Holder, on or after the
     Redemption Date or Repayment Date, as the case may be), or adversely affect
     any right to convert or exchange any Security as may be provided pursuant
     to Section 301 herein, or

         (2) reduce the percentage in principal amount of the 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 1009, except to increase any such percentage 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.

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

         It shall not be necessary for any Act of Holders under this Section 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 or the modifications thereby of
the trusts created by this Indenture, the Trustee shall be entitled to receive,
and (subject to TIA Section 315(a) through 315(d) and Section 602 hereof) 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 or
immunities under this Indenture or otherwise.




<PAGE>   73
                                       64


         SECTION 904. Effect of Supplemental Indentures.

         Upon the execution of any supplemental indenture under this Article,
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 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 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.

         SECTION 907. Notice of Supplemental Indentures.

         Promptly after the execution by the Company and the Trustee of any
supplemental indenture pursuant to the provisions of Section 902, the Company
shall give notice thereof to the Holders of each Outstanding Security affected,
in the manner provided for in Section 106, setting forth in general terms the
substance of such supplemental indenture.


                                   ARTICLE TEN

                                    COVENANTS

         SECTION 1001. Payment of Principal, Premium and Interest.

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




<PAGE>   74
                                       65


         SECTION 1002. Maintenance of Office or Agency.

         The Company will maintain in each Place of Payment for Securities of
such series an office or agency where Securities of such series may be presented
or surrendered for payment, where Securities of such series may be surrendered
for registration of transfer or exchange and where notices and demands to or
upon the Company in respect of the Securities of such series and this Indenture
may be served.

         The Company shall give prompt written notice to the Trustee of the
location, and any change in the location, of such office or agency. If at any
time the Company shall fail to maintain any such required office or agency or
shall fail to furnish the Trustee with the address thereof, such presentations,
surrenders, notices and demands may be made or served at the Corporate Trust
Office of the Trustee.

         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 accordance with the requirements set forth above for Securities of
any series for such purposes. The Company shall 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. Unless otherwise specified with
respect to any Securities pursuant to Section 301 with respect to a series of
Securities, the Company hereby designates as Places of Payment for each series
of Securities the office or agency of the Trustee in the Borough of Manhattan,
The City of New York, and initially appoints the Trustee at its Corporate Trust
Office in Chicago, Illinois and at the office of its agent in the Borough of
Manhattan, the City of New York as Paying Agent in each such city as its agent
to receive all such presentations, surrenders, notices and demands.

         SECTION 1003. Money for Security Payments to Be Held in Trust.

         If the Company shall at any time act as its own Paying Agent with
respect to any series of Securities, it shall, before each due date of the
principal of (and premium, if any, on) and interest, if any, on any of the
Securities of such series, segregate and hold in trust for the benefit of the
Persons entitled thereto a sum (except as otherwise specified pursuant to
Section 301 for the Securities of such) sufficient to pay the principal of (and
premium, if any, on) and interest, if any, on Securities of such Series 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.




<PAGE>   75
                                       66


         Whenever the Company shall have one or more Paying Agents for any
series of Securities it will, prior to or on each due date of the principal of
(and premium, if any, on) and interest, if any, on any Securities of such
series, deposit with the Paying Agent, a sum sufficient to pay the principal
(and premium, if any, on) 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) will promptly notify the
Trustee of its action or failure so to act.

         The Company shall cause each Paying Agent (other than the Trustee) for
any series of Securities 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, that such Paying Agent will:

         (1) hold all sums held by it for the payment of the principal of (and
     premium, if any, on) and interest, if any, on Securities of such 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 such series) in the making of any payment of
     principal (and premium, if any, on) and interest, if any, on the Securities
     of such 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
sums.

         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 (and premium, if
any, on) and interest, if any, on any Security of any series and remaining
unclaimed for two years after such principal (and premium, if any, on) or
interest has become due and payable, shall be paid to the Company on Company
Request, or (if then held by the Company) shall be discharged from such trust;
and the Holder of such Security shall thereafter, as an unsecured general
creditor, look only to the Company for payment thereof, and all liability of the
Trustee or such Paying



<PAGE>   76
                                       67


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,
notice that such money remains unclaimed and that, after a date specified
therein, which shall not be less than 30 days from the date of such publication,
any unclaimed balance of such money then remaining will be repaid to the
Company.

         SECTION 1004. Statement as to Compliance.

         The Company shall deliver to the Trustee, within 120 days after the end
of each fiscal year, commencing with its fiscal year ending after the date
hereof, a brief certificate from its principal executive officer, principal
financial officer or principal accounting officer as to his or her knowledge of
the compliance by the Company with all conditions and covenants under this
Indenture. For purposes of this Section 1004, such compliance shall be
determined without regard to any period of grace or requirement of notice under
this Indenture.

         SECTION 1005. Corporate Existence.

         Subject to Article Eight, the Company shall do or cause to be done all
things necessary to preserve and keep in full force and effect its respective
corporate existence, rights (charter and statutory) and franchises and the
respective corporate existence, rights (charter and statutory) and franchises of
its Subsidiaries; provided, however, that the Company shall not be required to
preserve any such existence, right or franchise if the Company shall determine
that the preservation thereof is no longer desirable in the conduct of the
business of it and its Subsidiaries as a whole and not disadvantageous in any
material respect to the Holders.

         SECTION 1006. Limitations on Liens.

         The Company covenants and agrees that it will not, and will not permit
any Restricted Subsidiary to, create, incur, issue or assume any Indebtedness
secured by any Lien on any Principal Property, or on shares of stock or
Indebtedness of any Restricted Subsidiary ("Restricted Securities"), without
making effective provision for the Outstanding Securities (except as otherwise
specified pursuant to Section 301 for the Securities of any series) to be
secured by the Lien equally and ratably with, or prior to, any and all
Indebtedness and obligations secured or to be secured thereby for so long as
such Indebtedness is so secured, except that the foregoing restriction shall
not apply to:

                  (1)      Any Lien existing on the date of the first issuance
         of Securities under the Indenture, including, but not limited to, the
         Liens on property or after-acquired property of the Company or its
         Subsidiaries under the United Cities Indenture or the Greeley
         Indenture.

                  (2)      Any Lien on any Principal Property or Restricted
         Securities of any Person existing at the time such Person is merged or
         consolidated with or into the Company or a Restricted Subsidiary, or 
         becomes a Restricted Subsidiary.

                  (3)      Any Lien on any Principal Property existing at the
         time of acquisition of such Principal Property by the Company or a
         Restricted Subsidiary, whether or not assumed by the Company or such
         Restricted Subsidiary, provided that no such Lien may extend to any
         other Principal Property of the Company or any Restricted Subsidiary.

                  (4)      Any Lien on any Principal Property (including any
         improvements on an existing Principal Property) of the Company or any
         Restricted Subsidiary, and any Lien on the shares of stock of a
         Restricted Subsidiary that was formed or is held for the purpose of
         acquiring and holding such Principal Property, in each case to secure
         all or any part of the cost of acquisition, development, operation,
         construction, alteration, repair or improvement of all or any part of
         such Principal Property (or to secure Indebtedness incurred by the
         Company or a Restricted Subsidiary for the purpose of financing all or
         any part of such cost); provided that such Lien is created prior to, at
         the time of, or within 12 months after the latest of, the acquisition,
         completion of construction or improvement or commencement of commercial
         operation of such Principal Property and provided, further, that no
         such Lien may extend to any other Principal Property of the Company or
         any Restricted Subsidiary, other than any theretofore unimproved real
         property on which the Principal Property is so constructed or developed
         or the improvement is located.

                  (5)      Any Lien on any Principal Property or Restricted
         Securities to secure Indebtedness owing to the Company or to another
         Restricted Subsidiary.

                  (6)      Any Lien in favor of governmental bodies to secure
         advances or other payments pursuant to any contract or statute or to
         secure Indebtedness incurred to finance the purchase price or cost of
         constructing or improving the property subject to such Lien.

                  (7)      Any Lien created in connection with a project
         financed with, and created to secure, Non-Recourse Indebtedness.

                  (8)      Any Lien required to be placed on any property of the
         Company or its Subsidiaries pursuant to the provisions of the Greeley
         Indenture, the United Cities Indenture, the Note Purchase Agreements or
         the Loan Agreement.

                  (9)      Any extension, renewal, substitution or replacement
         (or successive extensions, renewals, substitutions or replacements), in
         whole or in part, of any Lien referred to in the foregoing clauses (1)
         through (8), provided that the Indebtedness secured thereby may not
         exceed the principal amount of Indebtedness so secured at the time of
         such renewal or refunding, and that such renewal or refunding Lien must
         be limited to all or any part of the same property and improvements
         thereon, shares of stock or Indebtedness that secured the Lien renewed
         or refunded.

                  (10)     Any Lien not permitted above securing Indebtedness
         that, together with the aggregate outstanding principal amount of other
         secured Indebtedness that would otherwise be subject to the foregoing
         restrictions (excluding Indebtedness secured by Liens permitted under
         the foregoing exceptions) and the Attributable Debt in respect of all
         Sale and Leaseback Transactions (not including Attributable Debt in
         respect of any such Sale and Leaseback Transactions described in clause
         (3) or (4) of Section 1007) would not then exceed 10% of Consolidated
         Net Tangible Assets.

         SECTION 1007. Limitation on Sale and Leaseback Transactions.

         The Company convenants and agrees that it will not, and will not permit
any Restricted Subsidiary to, enter into any Sale and Leaseback Transaction
unless (i) the Company or a Restricted Subsidiary would be entitled, without
securing the Outstanding Securities, to incur Indebtedness secured by a Lien on
the Principal Property that is the subject of such Sale and Leaseback
Transaction pursuant to the provisions of Section 1006: (ii) the Attributable
Debt associated therewith would be in an amount permitted under Section 1006
(10); (iii) the proceeds received in respect of the Principal Property so sold
and leased back at the time of entering into such Sale and Leaseback
Transaction are used for the business and operations of the Company or any
Subsidiary; or (iv) within 12 months after the sale or transfer, an amount
equal to the proceeds received in respect of the Principal Property so sold and
leased back at the time of entering into such Sale and Leaseback Transaction is
applied to the prepayment (other than mandatory prepayment pursuant to Section
1201) of any Outstanding Securities or Funded Indebtedness of the Company or a
Restricted Subsidiary (other than Funded Indebtedness that is held by the
Company or any Restricted Subsidiary or Funded Indebtedness of the Company that
is subordinate in right of payment to any Outstanding Securities).

         SECTION 1008. Additional Amounts.

         If any Securities of a series provide for the payment of additional
amounts to any Holder who is not a United States person in respect of any tax,
assessment or governmental charge ("Additional Amounts"), the Company shall pay
to the Holder of any Security of such series such Additional Amounts as may be
specified pursuant to Section 301. Whenever in this Indenture there is
mentioned, in any context, the



<PAGE>   77
                                       68


payment of the principal of (and premium, if any, on) or interest, if any, on,
or in respect of, any Security of a series or the net proceeds received on the
sale or exchange of any Security of a series, such mention shall be deemed to
include mention of the payment of Additional Amounts provided for by the terms
of such series established pursuant to Section 301 to the extent that, in such
context, Additional Amounts are, were or would be payable in respect thereof
pursuant to such terms, 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. Except as otherwise specified pursuant to Section 301, if the Securities
of a series provide for the payment of Additional Amounts, at least 10 days
prior to the first Interest Payment Date, if any, with respect to Securities of
such series (or if the Securities of such series do not bear interest or will
not bear interest prior to Maturity, the first day on which a payment of
principal and any premium is made), and at least 10 days prior to each date of
payment of interest or principal and any premium 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 Paying Agent or
Paying Agents, if other than the Trustee, with an Officers' Certificate
instructing the Trustee and the Paying Agent or Paying Agents whether such
payment of principal of (and premium, if any, on) or interest, if any, on the
Securities of such series shall be made to Holders of Securities of such series
who are not United States persons without withholding for or on account of any
tax, assessment or other governmental charge described in the Securities of the
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 of such series and the Company
shall pay to the Trustee or the Paying Agent or Paying Agents the Additional
Amounts required by the terms of such Securities. In the event that the Trustee
or any Paying Agent, as the case may be, shall not so receive the
above-mentioned certificate, then the Trustee or such Paying Agent shall be
entitled (i) to assume that no such withholding or deduction is required with
respect to any payment of principal, premium or interest with respect to any
Securities of a series until it shall have received a certificate advising
otherwise and (ii) to make all payments of principal, premium and interest with
respect to the Securities of a series without withholding or deductions until
otherwise advised. The Company hereby covenants and agrees to indemnify the
Trustee and any Paying Agent for, and to hold them harmless against, any loss,
liability, cost 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.




<PAGE>   78
                                       69


         SECTION 1009. Waiver of Certain Covenants.

         Company may omit in any particular instance to comply with any term,
provision or condition set forth in Section 803 or Sections 1005 to 1007,
inclusive, if before or after the time for such compliance the Holders of at
least a majority in principal amount of all Outstanding Securities, by Act of
such Holders, waive such compliance in such instance or generally waive
compliance with such term, provision or condition, but no such waiver shall
extend to or affect such term, provision 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 term,
provision or condition shall remain in full force and effect.


                                 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 the terms of such Securities and
(except as otherwise specified as contemplated by Section 301 for Securities of
any series) in accordance with this Article.

         SECTION 1102. Election to Redeem; Notice to Trustee.

         The election of the Company to redeem any Securities shall be evidenced
by or pursuant to a Board Resolution. In case of any redemption at the election
of the Company, the Company shall, at least 60 days 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 and shall deliver to the Trustee
such documentation and records as shall enable the Trustee to select the
Securities to be redeemed pursuant to Section 1103. 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.




<PAGE>   79
                                       70


         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 which may provide for the selection for
redemption of portions of the principal of Securities of such series; provided,
however, that no such partial redemption shall reduce the portion of the
principal amount of a Security not redeemed to less than the minimum authorized
denomination for Securities of such series established pursuant to Section 301.

         The Trustee shall promptly notify the Company 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 Security redeemed or to be redeemed only in part, to the
portion of the principal amount of such Security which has been or is to be
redeemed.

         SECTION 1104. Notice of Redemption.

         Except as otherwise specified as contemplated by Section 301, notice of
redemption shall be given in the manner provided for in Section 106 not less
than 30 nor more than 60 days prior to the Redemption Date, to each Holder of
Securities to be redeemed.

         All notices of redemption shall identify the Securities (including
CUSIP number, if any) to be redeemed and shall state:

         (1) the Redemption Date,

         (2) the Redemption Price and the amount of accrued interest to the
     Redemption Date payable as provided in Section 1106, if any,

         (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) in case any Security is to be redeemed in part only, the notice
     which relates to such Security shall state that on and after the Redemption
     Date, upon surrender of such Security, the Holder will receive, without
     charge, a new Security or



<PAGE>   80
                                       71


     Securities of authorized denominations for the principal amount thereof
     remaining unredeemed,

         (5) that on the Redemption Date, the Redemption Price and accrued
     interest, if any, to the Redemption Date payable as provided in Section
     1106 will become due and payable upon each such Security, or the portion
     thereof, to be redeemed and, if applicable, that interest thereon will
     cease to accrue on and after said date,

         (6) the Place or Places of Payment where such Securities maturing after
     the Redemption Date, are to be surrendered for payment of the Redemption
     Price and accrued interest, if any, and

         (7) that the redemption is for a sinking fund, if such is the case.

         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.

         Prior to 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 (except as otherwise specified pursuant to Section 301 for the Securities
of such series) sufficient to pay the Redemption Price of, and accrued interest,
if any, on, 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 (except as otherwise specified pursuant to Section 301
for the Securities of such series)(together with accrued interest, if any, to
the Redemption Date), and from and after such date (unless the Company shall
default in the payment of the Redemption Price and accrued interest, if any)
such Securities shall, if the same were interest-bearing, cease to bear
interest, and except to the extent provided below, shall be void. 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, if any, to the Redemption Date; provided, however, that installments
of interest on Securities whose Stated Maturity is on or prior to the Redemption
Date shall be payable to the Holders of such Securities, or one or more



<PAGE>   81
                                       72


Predecessor Securities, registered as such at the close of business on the
relevant Record Dates according to their terms and the provisions of Section
308.

         If any Security called for redemption shall not be so paid upon
surrender thereof for redemption, the principal (and premium, if any) shall,
until paid, bear interest from the Redemption Date at the rate of interest or
Yield to Maturity (in the case of Original Issue Discount Securities) set forth
in such Security.

         SECTION 1107. Securities Redeemed in Part.

         Any Security which is to be redeemed only in part (pursuant to the
provisions of this Article or of Article Twelve) 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 such Holder's
attorney duly authorized in writing), and the Company shall execute, and the
Trustee shall authenticate and deliver to the Holder of such Security without
service charge, a new Security or Securities of the same series, 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.


                                 ARTICLE TWELVE

                                  SINKING FUNDS

         SECTION 1201. Applicability of Article.

         Retirements of Securities of any series pursuant to any sinking fund
shall be made in accordance with the terms of such Securities and (except as
otherwise specified as contemplated by Section 301 for Securities of any series)
in accordance with this Article.

         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". If provided for by the terms of Securities of any series,
the cash amount of any mandatory 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.




<PAGE>   82
                                       73


         SECTION 1202. Satisfaction of Sinking Fund Payments with Securities.

         Subject to Section 1203, in lieu of making all or any part of any
mandatory sinking fund payment with respect to any Securities of a series in
cash, the Company may at its option (1) deliver to the Trustee Outstanding
Securities of a series (other than any previously called for redemption)
theretofore purchased or otherwise acquired by the Company and/or (2) receive
credit for the principal amount of Securities of such series which have been
previously delivered to the Trustee by the Company or for Securities of such
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 mandatory sinking fund payment with
respect to the Securities of the same series required to be made pursuant to the
terms of such Securities as provided for by the terms of such series; provided,
however, 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 mandatory sinking fund payment shall
be reduced accordingly.

         SECTION 1203. Redemption of Securities for Sinking Fund.

         Not less than 60 days prior 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 (except as otherwise specified
pursuant to Section 301 for the Securities of such series) and the portion
thereof, if any, which is to be satisfied by delivering or crediting Securities
of that series pursuant to Section 1202 (which Securities will, if not
previously delivered, accompany such certificate) and whether the Company
intends to exercise its right to make a permitted optional sinking fund payment
with respect to such series. Such certificate shall be irrevocable and upon its
delivery the Company shall be obligated to make the cash payment or payments
therein referred to, if any, on or before the next succeeding sinking fund
payment date. In the case of the failure of the Company to deliver such
certificate, the sinking fund payment due on the next succeeding sinking fund
payment date for that series shall be paid entirely in cash and shall be
sufficient to redeem the principal amount of such Securities subject to a
mandatory sinking fund payment without the option to deliver or credit
Securities as provided in Section 1202 and without the right to make any
optional sinking fund payment, if any, with respect to such series.

         Not more than 60 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



<PAGE>   83
                                       74


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.

         Prior to any sinking fund payment date, the Company shall pay to the
Trustee or a Paying Agent (or, if the Company is acting as its own Paying Agent,
segregate and hold in trust as provided in Section 1003) in cash a sum equal to
any interest that will accrue to the date fixed for redemption of Securities or
portions thereof to be redeemed on such sinking fund payment date pursuant to
this Section 1203.

         Notwithstanding the foregoing, with respect to a sinking fund for any
series of Securities, if at any time the amount of cash to be paid into such
sinking fund on the next succeeding sinking fund payment date, together with any
unused balance of any preceding sinking fund payment or payments for such
series, does not exceed in the aggregate $100,000, the Trustee, unless requested
by the Company, shall not give the next succeeding notice of the redemption of
Securities of such series through the operation of the sinking fund. Any such
unused balance of moneys deposited in such sinking fund shall be added to the
sinking fund payment for such series to be made in cash on the next succeeding
sinking fund payment date or, at the written request of the Company, shall be
applied at any time or from time to time to the purchase of Securities of such
series, by public or private purchase, in the open market or otherwise, at a
purchase price for such Securities (excluding accrued interest and brokerage
commissions, for which the Trustee or any Paying Agent will be promptly
reimbursed by the Company) not in excess of the principal amount thereof.


                                ARTICLE THIRTEEN

                         REPAYMENT AT OPTION OF HOLDERS

         SECTION 1301. Applicability of Article.

         Repayment of Securities of any series before their Stated Maturity at
the option of Holders thereof shall be made in accordance with the terms of such
Securities and (except as otherwise specified as contemplated by Section 301 for
Securities of any series) in accordance with this Article.




<PAGE>   84
                                       75


         SECTION 1302. Repayment of Securities.

         Securities of any series subject to repayment in whole or in part at
the option of the Holders thereof will, unless otherwise provided in the terms
of such Securities, be repaid at a price equal to the principal amount thereof,
together with interest, if any, thereon accrued to the Repayment Date specified
in or pursuant to the terms of such Securities. The Company covenants that on or
before the Repayment Date it will 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 (except as otherwise
specified pursuant to Section 301 for the Securities of such series) sufficient
to pay the principal (or, if so provided by the terms of the Securities of any
series, a percentage of the principal) of and (except if the Repayment Date
shall be an Interest Payment Date) accrued interest, if any, on, all the
Securities or portions thereof, as the case may be, to be repaid on such date.

         SECTION 1303. Exercise of Option.

         Securities of any series subject to repayment at the option of the
Holders thereof will contain an "Option to Elect Repayment" form on the reverse
of such Securities. To be repaid at the option of the Holder, any Security so
providing for such repayment, with the "Option to Elect Repayment" form on the
reverse of such Security duly completed by the Holder (or by the Holder's
attorney duly authorized in writing), must be received by the Company at the
Place of Payment therefor specified in the terms of such Security (or at such
other place or places of which the Company shall from time to time notify the
Holders of such Securities) not earlier than 45 days nor later than 30 days
prior to the Repayment Date. If less than the entire principal amount of such
Security is to be repaid in accordance with the terms of such Security, the
principal amount of such Security to be repaid, in increments of the minimum
denomination for Securities of such series, and the denomination or
denominations of the Security or Securities to be issued to the Holder for the
portion of the principal amount of such Security surrendered that is not to be
repaid, must be specified. The principal amount of any Security providing for
repayment at the option of the Holder thereof may not be repaid in part if,
following such repayment, the unpaid principal amount of such Security would be
less than the minimum authorized denomination of Securities of the series of
which such Security to be repaid is a part. Except as otherwise may be provided
by the terms of any Security providing for repayment at the option of the Holder
thereof, exercise of the repayment option by the Holder shall be irrevocable
unless waived by the Company.




<PAGE>   85
                                       76


         SECTION 1304. When Securities Presented for Repayment Become Due and
Payable.

         If Securities of any series providing for repayment at the option of
the Holders thereof shall have been surrendered as provided in this Article and
as provided by or pursuant to the terms of such Securities, such Securities or
the portions thereof, as the case may be, to be repaid shall become due and
payable and shall be paid by the Company on the Repayment Date therein
specified, and on and after such Repayment Date (unless the Company shall
default in the payment of such Securities on such Repayment Date) such
Securities shall, if the same were interest-bearing, cease to bear interest and
except to the extent provided below, shall be void. Upon surrender of any such
Security for repayment in accordance with such provisions, the principal amount
of such Security so to be repaid shall be paid by the Company, together with
accrued interest, if any, to the Repayment Date; provided, however, that, in the
case of Securities, installments of interest, if any, whose Stated Maturity is
on or prior to the Repayment 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 308.

         If the principal amount of any Security surrendered for repayment shall
not be so repaid upon surrender thereof, such principal amount (together with
interest, if any, thereon accrued to such Repayment Date) shall, until paid,
bear interest from the Repayment Date at the rate of interest or Yield to
Maturity (in the case of Original Issue Discount Securities) set forth in such
Security.

         SECTION 1305. Securities Repaid in Part.

         Upon surrender of any Security which is to be repaid in part only, the
Company shall execute and the Trustee shall authenticate and deliver to the
Holder of such Security, without service charge and at the expense of the
Company, a new Security or Securities of the same series, of any authorized
denomination specified by the Holder, in an aggregate principal amount equal to
and in exchange for the portion of the principal of such Security so surrendered
which is not to be repaid.





<PAGE>   86
                                       77


                                ARTICLE FOURTEEN

                       DEFEASANCE AND COVENANT DEFEASANCE

         SECTION 1401. Company's Option to Effect Defeasance or Covenant
Defeasance.

         Except as otherwise specified as contemplated by Section 301 for
Securities of any series, the provisions of this Article Fourteen shall apply to
each series of Securities, and the Company may, at its option, effect defeasance
of the Securities of or within a series under Section 1402, or covenant
defeasance of the Securities of or within a series under Section 1403 in
accordance with the terms of such Securities and in accordance with this
Article.

         SECTION 1402. Defeasance and Discharge.

         Upon the Company's exercise of the above option applicable to this
Section with respect to any Securities of or within a series, the Company shall
be deemed to have been discharged from its obligations with respect to such
Outstanding Securities on the date the conditions set forth in Section 1404 are
satisfied (hereinafter, "defeasance"). For this purpose, such defeasance means
that the Company shall be deemed to have paid and discharged the entire
indebtedness represented by such Outstanding Securities, which shall thereafter
be deemed to be "Outstanding" only for the purposes of Section 1405 and the
other Sections of this Indenture referred to in (A) and (B) below, and to have
satisfied all its other obligations under such Securities and this Indenture
insofar as such Securities are concerned (and the Trustee, at the expense of the
Company, shall execute proper instruments acknowledging the same), except for
the following which shall survive until otherwise terminated or discharged
hereunder: (A) the rights of Holders of such Outstanding Securities to receive,
solely from the trust fund described in Section 1404 and as more fully set forth
in such Section, payments in respect of the principal of (and premium, if any)
and interest, if any, on such Securities  when such payments are due, (B) the
Company's obligations with respect to such Securities under Sections 305, 306,
307, 1002 and 1003 and with respect to the payment of Additional Amounts, if
any, on such Securities as contemplated by Section 1008, (C) the rights, powers,
trusts, duties and immunities of the Trustee hereunder and (D) this Article
Fourteen. Subject to compliance with this Article Fourteen, the Company may
exercise its option under this Section 1402 notwithstanding the prior exercise
of its option under Section 1403 with respect to such Securities.




<PAGE>   87
                                       78


         SECTION 1403. Covenant Defeasance.

         Upon the Company's exercise under Section 1401 of the option applicable
to this Section 1403 with respect to any Securities of or within a series, the
Company shall be released from its obligations under Sections 1006 and 1007, and
if specified pursuant to Section 301, its obligations under any other covenant,
with respect to such Outstanding Securities on and after the date the conditions
set forth in Section 1404 are satisfied (hereinafter, "covenant defeasance"),
and such Securities shall thereafter be deemed to be not "Outstanding" for the
purposes of any direction, waiver, consent or declaration or Act of Holders (and
the consequences of any thereof) in connection with such covenants, but shall
continue to be deemed "Outstanding" for all other purposes hereunder (it being
understood that such Securities shall not be deemed Outstanding for financial
accounting purposes). For this purpose, such covenant defeasance means that,
with respect to such Outstanding Securities, the Company may omit to comply with
and shall have no liability in respect of any term, condition or limitation set
forth in any such covenant, whether directly or indirectly, by reason of any
reference elsewhere herein to any such covenant or by reason of reference in any
such covenant to any other provision herein or in any other document and such
omission to comply shall not constitute a Default or an Event of Default under
Section 501(3) or Section 501(7) or otherwise, as the case may be, but, except
as specified above, the remainder of this Indenture and such Securities shall be
unaffected thereby.

         SECTION 1404. Conditions to Defeasance or Covenant Defeasance.

         The following shall be the conditions to application of either Section
1402 or Section 1403 to any Outstanding Securities of or within a series:

         (1) The Company shall irrevocably have deposited or caused to be 
     deposited with the Trustee (or another trustee satisfying the requirements
     of Section 608 who shall agree to comply with the provisions of this
     Article Fourteen applicable to it) as trust funds in trust for the purpose
     of making the following payments, specifically pledged as security for, and
     dedicated solely to, the benefit of the Holders of such Securities, (A) an
     amount or (B) Government Obligations applicable to such Securities which
     through the scheduled payment of principal and interest in respect thereof
     in accordance with their terms will provide, not later than one day before
     the due date of any payment of principal of and premium, if any, and
     interest, if any, under such Securities money in an amount, or (C) a
     combination thereof, sufficient, in the opinion of a nationally recognized
     firm of independent public accountants expressed in a written certification
     thereof delivered to the Trustee, to pay and discharge, and which shall be
     applied by the Trustee (or other qualifying trustee) to pay and discharge,
     (i) the principal of (and premium, if any) and



<PAGE>   88
                                       79


     interest, if any, on such Outstanding Securities on the Stated Maturity
     (or Redemption Date, if applicable) of such principal (and premium, if any)
     or installment of interest, if any, and (ii) any mandatory sinking fund
     payments or analogous payments applicable to such Outstanding Securities on
     the day on which such payments are due and payable in accordance with the
     terms of this Indenture and of such Securities; provided that the Trustee
     shall have been irrevocably instructed to apply such money or the proceeds
     of such Government Obligations to said payments with respect to such
     Securities. Before such a deposit, the Company may give to the Trustee, in
     accordance with Section 1102 hereof, a notice of its election to redeem all
     or any portion of such Outstanding Securities at a future date in
     accordance with the terms of the Securities of such series and Article
     Eleven hereof, which notice shall be irrevocable. Such irrevocable
     redemption notice, if given, shall be given effect in applying the
     foregoing.

         (2) No Default or Event of Default with respect to such Securities  
     shall have occurred and be continuing on the date of such deposit or,
     insofar as paragraphs (5) and (6) of Section 501 are concerned, at any time
     during 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).

         (3) No event or condition shall exist that would prevent the Company
     from making payments of the principal of (and premium, if any) or interest
     on the Securities on the date of such deposit or at any time during 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).

         (4) Such defeasance or covenant defeasance shall not result in a breach
     or violation of, or constitute a default under, this Indenture or any other
     material agreement or instrument to which the Company is a party or by
     which it is bound.

     (5) In the case of an election under Section 1402, the Company shall have
     delivered to the Trustee an Opinion of Counsel stating that (x) the Company
     has received from, or there has been published by, the Internal Revenue
     Service a ruling, or (y) since the date of execution of this Indenture,
     there has been a change in the applicable federal income tax law, in either
     case to the effect that, and based thereon such opinion shall confirm that,
     the Holders of such Outstanding Securities will not recognize income, gain
     or loss for federal income tax purposes as a result of such defeasance and
     will be subject to federal income tax on the same amounts, in the same
     manner and at the same times as would have been the case if such defeasance
     had not occurred.



<PAGE>   89
                                       80


         (6) In the case of an election under Section 1403, the Company shall
     have delivered to the Trustee an Opinion of Counsel to the effect that the
     Holders of such Outstanding Securities will not recognize income, gain or
     loss for federal income tax purposes as a result of such covenant
     defeasance and will be subject to federal income tax on the same amounts,
     in the same manner and at the same times as would have been the case if
     such covenant defeasance had not occurred.

         (7) In the case of an election under either Section 1402 or 1403, the
     Company shall represent to the Trustee that the deposit made by the Company
     pursuant to its election under Section 1402 or 1403 was not made by the
     Company with the intent of preferring the Holders of Securities of any
     series over other creditors of the Company or with the intent of defeating,
     hindering, delaying or defrauding creditors of the Company or others.

         (8) Notwithstanding any other provisions of this Section, such
     defeasance or covenant defeasance shall be effected in compliance with any
     additional or substitute terms, conditions or limitations in connection
     therewith pursuant to Section 301.

         (9) The Company shall have delivered to the Trustee an Officers'
     Certificate and an Opinion of Counsel, each stating that all conditions
     precedent provided for relating to either the defeasance under Section 1402
     or the covenant defeasance under Section 1403 (as the case may be) have
     been complied with.

         SECTION 1405. Deposited Money and Government Obligations to Be Held in
Trust; Other Miscellaneous Provisions.

         Subject to the provisions of the last paragraph of Section 1003, all
money and Government Obligations (or other property as may be provided pursuant
to Section 301) (including the proceeds thereof) deposited with the Trustee (or
other qualifying trustee, collectively for purposes of this Section 1405, the
"Trustee") pursuant to Section 1404 in respect of such Outstanding Securities
shall be held in trust and applied by the Trustee, in accordance with the
provisions of such 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 Holders of such Securities
of all sums due and to become due thereon in respect of principal (and premium,
if any) and interest, if any, but such money need not be segregated from other
funds except to the extent required by law.

         The Company shall pay and indemnify the Trustee against any tax, fee or
other charge imposed on or assessed against the Government Obligations deposited
pursuant to Section 1404 or the principal and interest received in respect
thereof other than any such tax,



<PAGE>   90
                                       81


fee or other charge which by law is for the account of the Holders of such
Outstanding Securities.

         Anything in this Article Fourteen to the contrary notwithstanding, the
Trustee shall deliver or pay to the Company from time to time upon Company
Request any money or Government Obligations (or other property and any proceeds
therefrom) held by it as provided in Section 1404 which, in the opinion of a
nationally recognized firm of independent public accountants expressed in a
written certification thereof delivered to the Trustee, are in excess of the
amount thereof which would then be required to be deposited to effect an
equivalent defeasance or covenant defeasance, as applicable, in accordance with
this Article.

         SECTION 1406. Reinstatement.

         If the Trustee or any Paying Agent is unable to apply any money in
accordance with Section 1405 by reason of any order or judgment of any court or
governmental authority enjoining, restraining or otherwise prohibiting such
application, then the Company's obligations under this Indenture and such
Securities shall be revived and reinstated as though no deposit had occurred
pursuant to Section 1402 or 1403, as the case may be, until such time as the
Trustee or Paying Agent is permitted to apply all such money in accordance with
Section 1405; provided, however, that if the Company makes any payment of
principal of (or premium, if any) or interest, if any, on any such Security
following 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 held by the Trustee or Paying Agent.

         This Indenture 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 Indenture.





<PAGE>   91
                                       82


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

                                    ATMOS ENERGY CORPORATION


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




                                    U.S. BANK TRUST NATIONAL ASSOCIATION


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








<PAGE>   1
                                                                  EXHIBIT 4.3(d)

                      AMENDMENT TO NOTE PURCHASE AGREEMENT

         THIS AMENDMENT TO NOTE PURCHASE AGREEMENT is made and entered into as
of the 22nd day of December, 1993 by and between ATMOS ENERGY CORPORATION
(formerly Energas Company), a Texas corporation ("Borrower"), and JOHN HANCOCK
MUTUAL LIFE INSURANCE COMPANY, a Massachusetts corporation ("Purchaser").

                              W I T N E S S E T H:

         WHEREAS, Borrower and Purchaser entered into that certain Note
Purchase Agreement dated as of December 21, 1987, as amended by two Amendments
to Note Purchase Agreement dated October 11, 1989 and November 12, 1991 (such
Note Purchase Agreement as amended being hereinafter referred to as the
"Agreement"), pursuant to which Borrower sold to Purchaser certain of its 8.94%
Senior Notes in an aggregate principal amount of $8,750,000 and certain of its
11.20% Senior Notes in an aggregate principal amount of $17,000,000; and

         WHEREAS, Borrower and Purchaser now desire to amend the Agreement in
the manner hereinafter set forth;

         NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

         1.      Section 1.02 of the Agreement shall be, and hereby is, amended
by adding the following definitions therein:

         "Tenth Supplemental Indenture" means that certain Tenth Supplemental
         Indenture dated as of December 1, 1993 between Borrower and Colorado
         National Bank (formerly Central Bank Denver, National Association).

         "Greeley Indenture" means the Indenture of Mortgage and Deed of Trust
         dated as of March 1, 1957 between Greeley Gas Company and the Central
         Bank and Trust Company, as Trustee, as supplemented by the First
         through Tenth Supplemental Indentures thereto (the obligations of
         Greeley Gas Company and its successors


                                     -1-
<PAGE>   2
         under the Greeley Indenture and under the bonds issued pursuant
         thereto having been assumed by the Company under the First Amendment
         to Bond Purchase Agreement dated as of December 1, 1993, between
         Borrower and First Colony Life Insurance Company).

         2.      Paragraph (B) of Section 4.10(b) of the Agreement shall be,
and hereby is, amended to read in its entirety as follows:

         (B)  Liens existing on any real property (including leaseholds) and
         fixtures thereon (and in the cases of the Liens of the Western
         Kentucky Indenture and Greeley Indenture, other property covered by
         the Western Kentucky Indenture as specifically limited by the Twelfth
         Supplemental Indenture or by the Greeley Indenture as specifically
         limited by the Tenth Supplemental Indenture) at the time of
         acquisition of such property by Borrower or by such Subsidiary through
         a merger or consolidation permitted under Section 4.04 above, whether
         or not assumed, or on any such property of a Subsidiary at the time
         such Subsidiary is acquired by Borrower or another Subsidiary in an
         acquisition permitted under Section 4.15; provided that every such
         Lien described in this clause (B) shall apply and attach only to the
         specific items of property originally subject thereto and fixed
         improvements constructed thereon (and including repairs thereto and
         replacements thereof) and any extensions located entirely in the State
         of Kentucky of the former Western Kentucky Gas Utility Corporation
         system with respect to the Lien of the Western Kentucky Indenture or
         extensions located in the States of Colorado, Kansas, or Missouri of
         the former Greeley Gas Company system with respect to the Lien of the
         Greeley Indenture and shall not extend to any other assets or property
         whatsoever (including, without limitation, to any property or assets
         of the acquiring entity or of the other corporation or corporations
         which are party to the merger or consolidation), other than such
         assets of the acquired company for so long as the acquired company
         shall remain a separate corporate entity; and provided further that at
         no time shall the aggregate principal amount of all Debt secured by
         Liens described in this clause (B), including without limitation the
         Liens of the Western Kentucky Indenture and Greeley Indenture, exceed
         55% of the aggregate cost (including the secured Debt) or fair value
         (without deducting the secured Debt), whichever is less, of the assets
         subject thereto (with the lower of cost or fair value to be determined
         separately with respect to each such asset);

         3.      Except to the extent amended or modified herein, the Agreement
is, and shall continue, in full force and effect in accordance with the terms
and provisions thereof.





                                      -2-
<PAGE>   3
         IN WITNESS WHEREOF, the parties hereto have executed this Amendment to
Note Purchase Agreement effective as of the date first written above.

ATMOS ENERGY CORPORATION              JOHN HANCOCK MUTUAL LIFE
                                      INSURANCE COMPANY

By: /s/ JAMES F. PURSER               By: /s/ MARILYN O. BOSS
    -------------------                   -------------------
    James F. Purser                       Marilyn O. Boss
    Executive Vice President              Investment Officer
    and Chief Financial Officer





                                      -3-
<PAGE>   4
                                                                  EXHIBIT 4.3(d)

                      AMENDMENT TO NOTE PURCHASE AGREEMENT

         THIS AMENDMENT TO NOTE PURCHASE AGREEMENT is made and entered into as
of the 22nd day of December, 1993 by and between ATMOS ENERGY CORPORATION
(formerly Energas Company), a Texas corporation ("Borrower"), and MELLON BANK
N.A., TRUSTEE UNDER MASTER TRUST AGREEMENT OF AT&T CORPORATION DATED JANUARY 1,
1984 FOR EMPLOYEE PENSION PLANS - AT&T - JOHN HANCOCK - PRIVATE PLACEMENT
("Purchaser").

                              W I T N E S S E T H:

         WHEREAS, Borrower and Purchaser entered into that certain Note
Purchase Agreement dated as of December 21, 1987, as amended by two Amendments
to Note Purchase Agreement dated October 11, 1989 and November 12, 1991 (such
Note Purchase Agreement as amended being hereinafter referred to as the
"Agreement"), pursuant to which Borrower sold to Purchaser certain of its 8.94%
Senior Notes in an aggregate principal amount of $1,250,000 and certain of its
11.20% Senior Notes in an aggregate principal amount of $2,500,000; and

         WHEREAS, Borrower and Purchaser now desire to amend the Agreement in
the manner hereinafter set forth;

         NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

         1.      Section 1.02 of the Agreement shall be, and hereby is, amended
by adding the following definitions therein:

         "Tenth Supplemental Indenture" means that certain Tenth Supplemental
         Indenture dated as of December 1, 1993 between Borrower and Colorado
         National Bank (formerly Central Bank Denver, National Association).

         "Greeley Indenture" means the Indenture of Mortgage and Deed of Trust
         dated as of March 1, 1957 between Greeley Gas Company and the Central
         Bank and Trust


                                     -1-
<PAGE>   5
         Company, as Trustee, as supplemented by the First through Tenth
         Supplemental Indentures thereto (the obligations of Greeley Gas
         Company and its successors under the Greeley Indenture and under the
         bonds issued pursuant thereto having been assumed by the Company under
         the First Amendment to Bond Purchase Agreement dated as of December 1,
         1993, between Borrower and First Colony Life Insurance Company).

         2.      Paragraph (B) of Section 4.10(b) of the Agreement shall be,
and hereby is, amended to read in its entirety as follows:

         (B)  Liens existing on any real property (including leaseholds) and
         fixtures thereon (and in the cases of the Liens of the Western
         Kentucky Indenture and Greeley Indenture, other property covered by
         the Western Kentucky Indenture as specifically limited by the Twelfth
         Supplemental Indenture or by the Greeley Indenture as specifically
         limited by the Tenth Supplemental Indenture) at the time of
         acquisition of such property by Borrower or by such Subsidiary through
         a merger or consolidation permitted under Section 4.04 above, whether
         or not assumed, or on any such property of a Subsidiary at the time
         such Subsidiary is acquired by Borrower or another Subsidiary in an
         acquisition permitted under Section 4.15; provided that every such
         Lien described in this clause (B) shall apply and attach only to the
         specific items of property originally subject thereto and fixed
         improvements constructed thereon (and including repairs thereto and
         replacements thereof) and any extensions located entirely in the State
         of Kentucky of the former Western Kentucky Gas Utility Corporation
         system with respect to the Lien of the Western Kentucky Indenture or
         extensions located in the States of Colorado, Kansas, or Missouri of
         the former Greeley Gas Company system with respect to the Lien of the
         Greeley Indenture and shall not extend to any other assets or property
         whatsoever (including, without limitation, to any property or assets
         of the acquiring entity or of the other corporation or corporations
         which are party to the merger or consolidation), other than such
         assets of the acquired company for so long as the acquired company
         shall remain a separate corporate entity; and provided further that at
         no time shall the aggregate principal amount of all Debt secured by
         Liens described in this clause (B), including without limitation the
         Liens of the Western Kentucky Indenture and Greeley Indenture, exceed
         55% of the aggregate cost (including the secured Debt) or fair value
         (without deducting the secured Debt), whichever is less, of the assets
         subject thereto (with the lower of cost or fair value to be determined
         separately with respect to each such asset);

         3.      Except to the extent amended or modified herein, the Agreement
is, and shall continue, in full force and effect in accordance with the terms
and provisions thereof.





                                      -2-
<PAGE>   6
         IN WITNESS WHEREOF, the parties hereto have executed this Amendment to
Note Purchase Agreement effective as of the date first written above.


ATMOS ENERGY CORPORATION                MELLON BANK N.A., TRUSTEE
                                        UNDER MASTER TRUST AGREEMENT
                                        OF AT&T CORPORATION DATED
By: /s/ JAMES F. PURSER                 JANUARY 1, 1984 FOR EMPLOYEE
    -------------------                 PENSION PLANS - AT&T-AS DIRECTED 
    Executive Vice President            BY JOHN HANCOCK - PRIVATE
    and Chief Financial Officer         PLACEMENT


                                        By: /s/ JUDITH A. MANION
                                            --------------------
                                            Judith A. Manion
                                            Paralegal





                                      -3-

<PAGE>   1
                                                                  EXHIBIT 4.3(e)

                                  AMENDMENT TO
                            NOTE PURCHASE AGREEMENT


         THIS AMENDMENT TO NOTE PURCHASE AGREEMENT is made and entered into as
of the 20th day of December, 1994 by and among ATMOS ENERGY CORPORATION
(formerly Energas Company), a Texas corporation ("Borrower"),  JOHN HANCOCK
MUTUAL LIFE INSURANCE COMPANY, a Massachusetts corporation, and MELLON BANK
N.A., TRUSTEE UNDER MASTER TRUST AGREEMENT OF AT&T CORPORATION DATED JANUARY 1,
1984 FOR EMPLOYEE PENSION PLANS - AT&T - JOHN HANCOCK - PRIVATE PLACEMENT (John
Hancock Mutual Life Insurance Company and Mellon Bank N.A., Trustee being
hereinafter collectively referred to as the "Purchasers").

                              W I T N E S S E T H:

         WHEREAS, Borrower and Purchasers entered into those certain Note
Purchase  Agreements, executed in multiple counterparts, dated as of December
21, 1987, as amended by two Amendments to Note Purchase Agreement dated October
11, 1989, November 12, 1991, and December 22, 1993 (such Note Purchase
Agreements as amended being hereinafter referred to as the "Agreement"),
pursuant to which Borrower sold to Purchasers its 8.94% Senior Notes in an
aggregate principal amount of $10,000,000 and its 11.20% Senior Notes in an
aggregate principal amount of $20,000,000; and

         WHEREAS, Borrower and Purchasers now desire to amend the Agreement in
the manner hereinafter set forth, as evidenced by the execution hereof by the
requisite percentage of the Purchasers holding the Senior Notes; and


                                     -1-
<PAGE>   2
         WHEREAS, Borrower has notified Purchasers that, effective December 31,
1994, Enermart, Inc., a Delaware corporation and Wholly Owned Subsidiary of
Borrower, will transfer all of its assets into a Pennsylvania business trust,
known as Enermart Trust, of which Enermart, Inc. is the sole certificate
holder, and Borrower has requested Purchasers' consent to such transfer of
assets;

         NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

         1.      The definition of "Subsidiary" in Section 1.02 of the
Agreement shall be, and hereby is, amended to read in its entirety as follows:

         "Subsidiary" means each corporation, trust, partnership, or
         association in which the Borrower owns, directly or through another
         such corporation, trust, partnership, or association, fifty percent or
         more of the voting securities.  All references in the Agreements with
         respect to a Subsidiary organized in the form of a corporate entity
         shall be deemed, when appropriate, to refer also to a Subsidiary
         organized in the form of a trust, partnership, or association."

         2.      Section 3.01(b) of the Agreement shall be, and hereby is,
amended by adding the following sentence at the end of such section:

         "Enermart, Inc. is, and shall at all times be, the sole certificate
         holder of Enermart Trust, and Enermart Trust shall at all times be
         deemed a Wholly Owned Subsidiary under the Agreements and shall be
         bound by all applicable provisions of the Agreements."

         3.       Purchasers, by  their execution of this Amendment to Note
Purchase Agreement, hereby consent to the transfer of the assets of Enermart,
Inc. to Enermart Trust as described above.





                                      -2-
<PAGE>   3
         4.      Except to the extent amended or modified herein, the Agreement
is, and shall continue, in full force and effect in accordance with the terms
and provisions thereof.

         5.      This Amendment to Note Purchase Agreement may be executed in
multiple counterparts, all of which shall constitute one instrument.

         IN WITNESS WHEREOF, the parties hereto have executed this Amendment to
Note Purchase Agreement effective as of the date first written above.

ATMOS ENERGY CORPORATION             JOHN HANCOCK MUTUAL LIFE
                                     INSURANCE COMPANY


By: /s/ JAMES F. PURSER              By: /s/ MARILYN O. BOSS
    -------------------                  -------------------
    James F. Purser                          Marilyn O. Boss
    Executive Vice President and             Investment Officer
    Chief Financial Officer

                                     MELLON BANK N.A., TRUSTEE
                                     UNDER MASTER TRUST AGREEMENT
                                     OF AT&T CORPORATION DATED
                                     JANUARY 1, 1984 FOR EMPLOYEE
                                     PENSION PLANS - AT&T - JOHN
                                     HANCOCK - PRIVATE PLACEMENT
                                     DIRECTED BY JOHN HANCOCK 
                                     MUTUAL LIFE INSURANCE COMPANY

                                     By: /s/ JUDITH A. MANION
                                         --------------------
                                             Judith A. Manion
                                             Assistant Officer





                                      -3-
<PAGE>   4
                                                                  EXHIBIT 4.3(e)

                                  AMENDMENT TO
                            NOTE PURCHASE AGREEMENT


         THIS AMENDMENT TO NOTE PURCHASE AGREEMENT is made and entered into as
of the 20th day of December, 1994 by and among ATMOS ENERGY CORPORATION
(formerly Energas Company), a Texas corporation ("Borrower"),  JOHN HANCOCK
MUTUAL LIFE INSURANCE COMPANY, a Massachusetts corporation, and MELLON BANK
N.A., TRUSTEE UNDER MASTER TRUST AGREEMENT OF AT&T CORPORATION DATED JANUARY 1,
1984 FOR EMPLOYEE PENSION PLANS - AT&T - JOHN HANCOCK - PRIVATE PLACEMENT (John
Hancock Mutual Life Insurance Company and Mellon Bank N.A., Trustee being
hereinafter collectively referred to as the "Purchasers").

                              W I T N E S S E T H:

         WHEREAS, Borrower and Purchasers entered into those certain Note
Purchase  Agreements, executed in multiple counterparts, dated as of December
21, 1987, as amended by two Amendments to Note Purchase Agreement dated October
11, 1989, November 12, 1991, and December 22, 1993 (such Note Purchase
Agreements as amended being hereinafter referred to as the "Agreement"),
pursuant to which Borrower sold to Purchasers its 8.94% Senior Notes in an
aggregate principal amount of $10,000,000 and its 11.20% Senior Notes in an
aggregate principal amount of $20,000,000; and

         WHEREAS, Borrower and Purchasers now desire to amend the Agreement in
the manner hereinafter set forth, as evidenced by the execution hereof by the
requisite percentage of the Purchasers holding the Senior Notes; and


                                     -1-
<PAGE>   5
         WHEREAS, Borrower has notified Purchasers that, effective December 31,
1994, Enermart, Inc., a Delaware corporation and Wholly Owned Subsidiary of
Borrower, will transfer all of its assets into a Pennsylvania business trust,
known as Enermart Trust, of which Enermart, Inc. is the sole certificate
holder, and Borrower has requested Purchasers' consent to such transfer of
assets;

         NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

         1.      The definition of "Subsidiary" in Section 1.02 of the
Agreement shall be, and hereby is, amended to read in its entirety as follows:

         "Subsidiary" means each corporation, trust, partnership, or
         association in which the Borrower owns, directly or through another
         such corporation, trust, partnership, or association, fifty percent or
         more of the voting securities.  All references in the Agreements with
         respect to a Subsidiary organized in the form of a corporate entity
         shall be deemed, when appropriate, to refer also to a Subsidiary
         organized in the form of a trust, partnership, or association."

         2.      Section 3.01(b) of the Agreement shall be, and hereby is,
amended by adding the following sentence at the end of such section:

         "Enermart, Inc. is, and shall at all times be, the sole certificate
         holder of Enermart Trust, and Enermart Trust shall at all times be
         deemed a Wholly Owned Subsidiary under the Agreements and shall be
         bound by all applicable provisions of the Agreements."

         3.       Purchasers, by  their execution of this Amendment to Note
Purchase Agreement, hereby consent to the transfer of the assets of Enermart,
Inc. to Enermart Trust as described above.





                                      -2-
<PAGE>   6
         4.      Except to the extent amended or modified herein, the Agreement
is, and shall continue, in full force and effect in accordance with the terms
and provisions thereof.

         5.      This Amendment to Note Purchase Agreement may be executed in
multiple counterparts, all of which shall constitute one instrument.

         IN WITNESS WHEREOF, the parties hereto have executed this Amendment to
Note Purchase Agreement effective as of the date first written above.

ATMOS ENERGY CORPORATION              JOHN HANCOCK MUTUAL LIFE
                                      INSURANCE COMPANY


By: /s/ JAMES F. PURSER               By: /s/ MARILYN O. BOSS
    -------------------                   -------------------
    James F. Purser                           Marilyn O. Boss
    Executive Vice President and              Investment Officer
    Chief Financial Officer

                                      MELLON BANK N.A., TRUSTEE
                                      UNDER MASTER TRUST AGREEMENT
                                      OF AT&T CORPORATION DATED
                                      JANUARY 1, 1984 FOR EMPLOYEE
                                      PENSION PLANS - AT&T - JOHN
                                      HANCOCK - PRIVATE PLACEMENT
                                      DIRECTED BY JOHN HANCOCK 
                                      MUTUAL LIFE INSURANCE COMPANY

                                      By: /s/ JUDITH A. MANION
                                          --------------------
                                              Judith A. Manion
                                              Assistant Officer





                                      -3-

<PAGE>   1
                                                                  EXHIBIT 4.3(f)

                      AMENDMENT TO NOTE PURCHASE AGREEMENT


         THIS AMENDMENT TO NOTE PURCHASE AGREEMENT is made and entered into as
of the 29th day of July, 1997 by and between ATMOS ENERGY CORPORATION, a Texas
corporation ("Borrower"), and JOHN HANCOCK MUTUAL LIFE INSURANCE COMPANY, a
Massachusetts corporation ("Purchaser").

                              W I T N E S S E T H:

         WHEREAS, Borrower and Purchaser entered into that certain Note
Purchase Agreement dated as of December 21, 1987, as amended by four Amendments
to Note Purchase Agreement dated October 11, 1989, November 12, 1991, December
22, 1993 and December 20, 1994 (such Note Purchase Agreement as amended being
hereinafter referred to as the "Agreement"), pursuant to which Borrower sold to
Purchaser certain of its 8.94% Senior Notes in an aggregate principal amount of
$8,750,000 and certain of its 11.20% Senior Notes in an aggregate principal
amount of $17,500,000; and

         WHEREAS, Borrower and Purchaser now desire to amend the Agreement in
the manner hereinafter set forth;

         NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

         1.      Section 1.02 of the Agreement shall be, and hereby is, amended
by adding the following definitions therein:

                 "Twenty-Second Supplemental Indenture" means that certain
                 Twenty-Second Supplemental Indenture dated as of July 29, 1997
                 between


                                      1
<PAGE>   2
                 Borrower and First Trust National Association (as successor to
                 Bank of America Illinois, Continental Bank, N.A., and City
                 National Bank and Trust Company of Chicago) and Russell C.
                 Bergman (as successor to M.J. Kruger and R. Emmett Hanley).

                 "United Cities Indenture" means the Indenture of Mortgage
                 dated as of July 15, 1959 between United Cities Gas Company
                 and City National Bank and Trust Company of Chicago and R.
                 Emmett Hanley, as Trustees, as supplemented by the First
                 through Twenty-Second Supplemental Indentures thereto (the
                 obligations of United Cities Gas Company and its successors
                 under the United Cities Indenture and under the bonds issued
                 pursuant thereto having been assumed by the Company under the
                 Twenty-Second Supplemental Indenture).

         2.      Paragraph (B) of Section 4.10(b) of the Agreement shall be,
and hereby is, amended to read in its entirety as follows:

                 (B)      Liens existing on any real property (including
                 leaseholds) and fixtures thereon (and in the cases of the
                 Liens of the Greeley Indenture and United Cities Indenture,
                 other property covered by the Greeley Indenture as
                 specifically limited by the Tenth Supplemental Indenture or by
                 the United Cities Indenture as specifically limited by the
                 Twenty-Second Supplemental Indenture) at the time of
                 acquisition of such property by Borrower or by such Subsidiary
                 through a merger or consolidation permitted under Section 4.04
                 above, whether or not assumed, or on any such property of a
                 Subsidiary at the time such Subsidiary is acquired by Borrower
                 or another Subsidiary in an acquisition permitted under
                 Section 4.15; provided that every such Lien described in this
                 clause (B) shall apply and attach only to the specific items
                 of property originally subject thereto and fixed improvements
                 constructed thereon (and including repairs thereto and
                 replacements thereof) and any extensions located in the States
                 of Colorado, Kansas, or Missouri of the former Greeley Gas
                 Company system with respect to the Lien of the Greeley
                 Indenture or extensions located in the States of Georgia,
                 Illinois, Iowa, Kansas, Kentucky, Missouri, North Carolina,
                 South Carolina, Tennessee, or Virginia of the former United
                 Cities Gas Company system with respect to the Lien of the
                 United Cities Indenture and shall not extend to any other
                 assets or property whatsoever (including, without limitation,
                 to any property or assets of the acquiring entity or of the
                 other corporation or corporations which are party to the
                 merger





                                       2
<PAGE>   3
                 or consolidation), other than such assets of the acquired
                 company for so long as the acquired company shall remain a
                 separate corporate entity; and provided further that at no
                 time shall the aggregate principal amount of all Debt secured
                 by Liens described in this clause (B), including without
                 limitation the Liens of the Greeley Indenture and United
                 Cities Indenture, exceed 55% of the aggregate cost (including
                 the secured Debt) or fair value (without deducting the secured
                 Debt), whichever is less, of the assets subject thereto (with
                 the lower of cost or fair value to be determined separately
                 with respect to each such asset);

         3.      Except to the extent amended or modified herein, the Agreement
is, and shall continue, in full force and effect in accordance with the terms
and provisions thereof.

         IN WITNESS WHEREOF, the parties hereto have executed this Amendment to
Note Purchase Agreement effective as of the date first written above.


ATMOS ENERGY CORPORATION               JOHN HANCOCK MUTUAL LIFE
                                       INSURANCE COMPANY


By: /s/ LARRY J. DAGLEY                By: /s/ MARILYN O. BOSS
    -------------------                    -------------------
    Larry J. Dagley                    Printed/Typed Name: Marilyn O. Boss
    Executive Vice President and       Title: Investment Officer
    Chief Financial Officer





                                       3
<PAGE>   4
                                                                  EXHIBIT 4.3(f)

                      AMENDMENT TO NOTE PURCHASE AGREEMENT


         THIS AMENDMENT TO NOTE PURCHASE AGREEMENT is made and entered into as
of the 29th day of July, 1997 by and between ATMOS ENERGY CORPORATION (formerly
Energas Company), a Texas corporation ("Borrower"), and MELLON BANK N.A.,
TRUSTEE UNDER MASTER TRUST AGREEMENT OF AT&T CORPORATION DATED JANUARY 1, 1984
FOR EMPLOYEE PENSION PLANS - AT&T - JOHN HANCOCK - PRIVATE PLACEMENT
("Purchaser").

                              W I T N E S S E T H:

         WHEREAS, Borrower and Purchaser entered into that certain Note
Purchase Agreement dated as of December 21, 1987, as amended by four Amendments
to Note Purchase Agreement dated October 11, 1989, November 12, 1991, December
22, 1993 and December 20, 1994  (such Note Purchase Agreement as amended being
hereinafter referred to as the "Agreement"), pursuant to which Borrower sold to
Purchaser certain of its 8.94% Senior Notes in an aggregate principal amount of
$1,250,000 and certain of its 11.20% Senior Notes in an aggregate principal
amount of $2,500,000; and

         WHEREAS, Borrower and Purchaser now desire to amend the Agreement in
the manner hereinafter set forth;

         NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:


                                      1
<PAGE>   5
         1.      Section 1.02 of the Agreement shall be, and hereby is, amended
by adding the following definitions therein:

                 "Twenty-Second Supplemental Indenture" means that certain
                 Twenty-Second Supplemental Indenture dated as of July 29, 1997
                 between Borrower and First Trust National Association (as
                 successor to Bank of America Illinois, Continental Bank, N.A.,
                 and City National Bank and Trust Company of Chicago) and
                 Russell C. Bergman (as successor to M.J. Kruger and R. Emmett
                 Hanley).

                 "United Cities Indenture" means the Indenture of Mortgage
                 dated as of July 15, 1959 between United Cities Gas Company
                 and City National Bank and Trust Company of Chicago and R.
                 Emmett Hanley, as Trustees, as supplemented by the First
                 through Twenty-Second Supplemental Indentures thereto (the
                 obligations of United Cities Gas Company and its successors
                 under the United Cities Indenture and under the bonds issued
                 pursuant thereto having been assumed by the Company under the
                 Twenty-Second Supplemental Indenture).

         2.      Paragraph (B) of Section 4.10(b) of the Agreement shall be,
and hereby is, amended to read in its entirety as follows:

                 (B)      Liens existing on any real property (including
                 leaseholds) and fixtures thereon (and in the cases of the
                 Liens of the Greeley Indenture and United Cities Indenture,
                 other property covered by the Greeley Indenture as
                 specifically limited by the Tenth Supplemental Indenture or by
                 the United Cities Indenture as specifically limited by the
                 Twenty-Second Supplemental Indenture) at the time of
                 acquisition of such property by Borrower or by such Subsidiary
                 through a merger or consolidation permitted under Section 4.04
                 above, whether or not assumed, or on any such property of a
                 Subsidiary at the time such Subsidiary is acquired by Borrower
                 or another Subsidiary in an acquisition permitted under
                 Section 4.15; provided that every such Lien described in this
                 clause (B) shall apply and attach only to the specific items
                 of property originally subject thereto and fixed improvements
                 constructed thereon (and including repairs thereto and
                 replacements thereof) and any extensions located in the States
                 of Colorado, Kansas, or Missouri of the former Greeley Gas
                 Company system with respect to the Lien of the Greeley
                 Indenture or extensions located in the States of Georgia,
                 Illinois,





                                       2
<PAGE>   6
                 Iowa, Kansas, Kentucky, Missouri, North Carolina, South
                 Carolina, Tennessee, or Virginia of the former United Cities
                 Gas Company system with respect to the Lien of the United
                 Cities Indenture and shall not extend to any other assets or
                 property whatsoever (including, without limitation, to any
                 property or assets of the acquiring entity or of the other
                 corporation or corporations which are party to the merger or
                 consolidation), other than such assets of the acquired company
                 for so long as the acquired company shall remain a separate
                 corporate entity; and provided further that at no time shall
                 the aggregate principal amount of all Debt secured by Liens
                 described in this clause (B), including without limitation the
                 Liens of the Greeley Indenture and United Cities Indenture,
                 exceed 55% of the aggregate cost (including the secured Debt)
                 or fair value (without deducting the secured Debt), whichever
                 is less, of the assets subject thereto (with the lower of cost
                 or fair value to be determined separately with respect to each
                 such asset);

         3.      Except to the extent amended or modified herein, the Agreement
is, and shall continue, in full force and effect in accordance with the terms
and provisions thereof.

         IN WITNESS WHEREOF, the parties hereto have executed this Amendment to
Note Purchase Agreement effective as of the date first written above.


ATMOS ENERGY CORPORATION                  MELLON BANK N.A., TRUSTEE UNDER
                                          MASTER TRUST AGREEMENT OF AT&T
                                          CORPORATION DATED JANUARY 1, 1984 
By: /s/ LARRY J. DAGLEY                   FOR EMPLOYEE PENSION PLANS - AT&T 
    -------------------                   - JOHN HANCOCK - PRIVATE PLACE-
    Larry J. Dagley                       MENT (AS DIRECTED BY JOHN    
    Executive Vice President and          HANCOCK MUTUAL LIFE INSURANCE
    Chief Financial Officer               COMPANY)

                                          By: /s/ SUSAN G. TESTA 
                                              --------------------
                                          Printed/Typed Name: Susan G. Testa
                                          Title: Trust Officer 
                                          





                                       3

<PAGE>   1
                                                                  EXHIBIT 4.4(c)

                      AMENDMENT TO NOTE PURCHASE AGREEMENT


         THIS AMENDMENT TO NOTE PURCHASE AGREEMENT is made and entered into as
of the 22nd day of December, 1993 by and between ATMOS ENERGY CORPORATION, a
Texas corporation ("Borrower"), and JOHN HANCOCK MUTUAL LIFE INSURANCE COMPANY,
a Massachusetts corporation ("Purchaser").

                              W I T N E S S E T H:

         WHEREAS, Borrower and Purchaser entered into that certain Note
Purchase Agreement dated as of October 11, 1989, as amended by an Amendment to
Note Purchase Agreement dated November 12, 1991 (such Note Purchase Agreement
as amended being hereinafter referred to as the "Agreement"), pursuant to which
Borrower sold to Purchaser certain of its 9.76% Senior Notes in an aggregate
principal amount of $30,000,000; and

         WHEREAS, Borrower and Purchaser now desire to amend the Agreement in
the manner hereinafter set forth;

         NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

         1.      Section 1.02 of the Agreement shall be, and hereby is, amended
by adding the following definitions therein:

         "Tenth Supplemental Indenture" means that certain Tenth Supplemental
         Indenture dated as of December 1, 1993 between Borrower and Colorado
         National Bank (formerly Central Bank Denver, National Association).

         "Greeley Indenture" means the Indenture of Mortgage and Deed of Trust
         dated as of March 1, 1957 between Greeley Gas Company and the Central
         Bank and Trust Company, as Trustee, as supplemented by the First
         through Tenth Supplemental Indentures thereto (the obligations of
         Greeley Gas Company and its successors under the Greeley Indenture and
         under the bonds issued pursuant thereto having been assumed by the
         Company under the First Amendment to Bond Purchase


                                     -1-
<PAGE>   2
         Agreement dated as of December 1, 1993, between Borrower and First
         Colony Life Insurance Company).

         2.      Paragraph (B) of Section 4.10(b) of the Agreement shall be,
and hereby is, amended to read in its entirety as follows:

         (B)  Liens existing on any real property (including leaseholds) and
         fixtures thereon (and in the cases of the Liens of the Western
         Kentucky Indenture and Greeley Indenture, other property covered by
         the Western Kentucky Indenture as specifically limited by the Twelfth
         Supplemental Indenture or by the Greeley Indenture as specifically
         limited by the Tenth Supplemental Indenture) at the time of
         acquisition of such property by Borrower or by such Subsidiary through
         a merger or consolidation permitted under Section 4.04 above, whether
         or not assumed, or on any such property of a Subsidiary at the time
         such Subsidiary is acquired by Borrower or another Subsidiary in an
         acquisition permitted under Section 4.15; provided that every such
         Lien described in this clause (B) shall apply and attach only to the
         specific items of property originally subject thereto and fixed
         improvements constructed thereon (and including repairs thereto and
         replacements thereof) and any extensions located entirely in the State
         of Kentucky of the former Western Kentucky Gas Utility Corporation
         system with respect to the Lien of the Western Kentucky Indenture or
         extensions located in the States of Colorado, Kansas, or Missouri of
         the former Greeley Gas Company system with respect to the Lien of the
         Greeley Indenture and shall not extend to any other assets or property
         whatsoever (including, without limitation, to any property or assets
         of the acquiring entity or of the other corporation or corporations
         which are party to the merger or consolidation), other than such
         assets of the acquired company for so long as the acquired company
         shall remain a separate corporate entity; and provided further that at
         no time shall the aggregate principal amount of all Debt secured by
         Liens described in this clause (B), including without limitation the
         Liens of the Western Kentucky Indenture and Greeley Indenture, exceed
         55% of the aggregate cost (including the secured Debt) or fair value
         (without deducting the secured Debt), whichever is less, of the assets
         subject thereto (with the lower of cost or fair value to be determined
         separately with respect to each such asset);

          3.     Except to the extent amended or modified herein, the Agreement
is, and shall continue, in full force and effect in accordance with the terms
and provisions thereof.





                                      -2-
<PAGE>   3
         IN WITNESS WHEREOF, the parties hereto have executed this Amendment to
Note Purchase Agreement effective as of the date first written above.


ATMOS ENERGY CORPORATION                JOHN HANCOCK MUTUAL LIFE
                                        INSURANCE COMPANY


By: /s/ JAMES F. PURSER                 By: /s/ MARILYN O. BOSS
    -------------------                     -------------------
    James F. Purser                             Marilyn O. Boss
    Executive Vice President                    Investment Officer
    and Chief Financial Officer





                                      -3-

<PAGE>   1
                                                                  EXHIBIT 4.4(d)

                                  AMENDMENT TO
                            NOTE PURCHASE AGREEMENT


         THIS AMENDMENT TO NOTE PURCHASE AGREEMENT is made and entered into as
of the 20th day of December, 1994 by and between ATMOS ENERGY CORPORATION, a
Texas corporation ("Borrower"), and JOHN HANCOCK MUTUAL LIFE INSURANCE COMPANY,
a Massachusetts corporation ("Purchaser").

                              W I T N E S S E T H:

         WHEREAS, Borrower and Purchaser entered into that certain Note
Purchase Agreement dated as of October 11, 1989, as amended by Amendments to
Note Purchase Agreement dated November 12, 1991 and December 22, 1993 (the
"Agreement"), pursuant to which Borrower sold to Purchaser its 9.76% Senior
Notes in an aggregate principal amount of $30,000,000; and

         WHEREAS, Borrower and Purchaser now desire to amend the Agreement in
the manner hereinafter set forth; and

         WHEREAS, Borrower has notified Purchaser that, effective December 31,
1994, Enermart, Inc., a Delaware corporation and Wholly Owned Subsidiary of
Borrower, will transfer all of its assets into a Pennsylvania business trust,
known as Enermart Trust, of which Enermart, Inc. is the sole certificate
holder, and Borrower has requested Purchaser's consent to such transfer of
assets;

         NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:


                                     -1-
<PAGE>   2
         1.      The definition of "Subsidiary" in Section 1.02 of the
Agreement shall be, and hereby is, amended to read in its entirety as follows:

         "Subsidiary" means each corporation, trust, partnership, or
         association in which the Borrower owns, directly or through another
         such corporation, trust, partnership, or association, fifty percent or
         more of the voting securities.  All references in the Agreements with
         respect to a Subsidiary organized in the form of a corporate entity
         shall be deemed, when appropriate, to refer also to a Subsidiary
         organized in the form of a trust, partnership, or association."

         2.      Section 3.01(b) of the Agreement shall be, and hereby is,
amended by adding the following sentence at the end of such section:

         "Enermart, Inc. is, and shall at all times be, the sole certificate
         holder of Enermart Trust, and Enermart Trust shall at all times be
         deemed a Wholly Owned Subsidiary under the Agreements and shall be
         bound by all applicable provisions of the Agreements."

         3.       Purchaser, by its execution of this Amendment to Note
Purchase Agreement, hereby consents to the transfer of the assets of Enermart,
Inc. to Enermart Trust as described above.

         4.      Except to the extent amended or modified herein, the Agreement
is, and shall continue, in full force and effect in accordance with the terms
and provisions thereof.

         5.      This Amendment to Note Purchase Agreement may be executed in
multiple counterparts, all of which shall constitute one instrument.





                                      -2-
<PAGE>   3
         IN WITNESS WHEREOF, the parties hereto have executed this Amendment to
Note Purchase Agreement effective as of the date first written above.

ATMOS ENERGY CORPORATION               JOHN HANCOCK MUTUAL LIFE
                                       INSURANCE COMPANY


By: /s/ JAMES F. PURSER                By: /s/ MARILYN O. BOSS
    -------------------                    -------------------
    James F. Purser                            Marilyn O. Boss
    Executive Vice President and               Investment Officer
    Chief Financial Officer





                                      -3-

<PAGE>   1
                                                                  EXHIBIT 4.4(e)

                      AMENDMENT TO NOTE PURCHASE AGREEMENT


         THIS AMENDMENT TO NOTE PURCHASE AGREEMENT is made and entered into as
of the 29th day of July, 1997 by and between ATMOS ENERGY CORPORATION, a Texas
corporation ("Borrower"), and JOHN HANCOCK MUTUAL LIFE INSURANCE COMPANY, a
Massachusetts corporation ("Purchaser").

                              W I T N E S S E T H:

         WHEREAS, Borrower and Purchaser entered into that certain Note
Purchase Agreement dated as of October 11, 1989, as amended by three Amendments
to Note Purchase Agreement dated November 12, 1991, December 22, 1993 and
December 20, 1994 (such Note Purchase Agreement as amended being hereinafter
referred to as the "Agreement"), pursuant to which Borrower sold to Purchaser
certain of its 9.76% Senior Notes in an aggregate principal amount of
$30,000,000; and

         WHEREAS, Borrower and Purchaser now desire to amend the Agreement in
the manner hereinafter set forth;

         NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

         1.      Section 1.02 of the Agreement shall be, and hereby is, amended
by adding the following definitions therein:

                 "Twenty-Second Supplemental Indenture" means that certain
                 Twenty-Second Supplemental Indenture dated as of July 29,
                 1997, between Borrower and First Trust National Association
                 (as successor to Bank of America Illinois, Continental Bank,
                 N.A., and City National Bank and Trust Company of Chicago) and
                 Russell C. Bergman (as successor to M.J. Kruger and R. Emmett
                 Hanley).


                                      1
<PAGE>   2
                 "United Cities Indenture" means the Indenture of Mortgage
                 dated as of July 15, 1959 between United Cities Gas Company
                 and City National Bank and Trust Company of Chicago and R.
                 Emmett Hanley, as Trustees, as supplemented by the First
                 through Twenty-Second Supplemental Indentures thereto (the
                 obligations of United Cities Gas Company and its successors
                 under the United Cities Indenture and under the bonds issued
                 pursuant thereto having been assumed by the Company under the
                 Twenty-Second Supplemental Indenture).

         2.      Paragraph (B) of Section 4.10(b) of the Agreement shall be,
and hereby is, amended to read in its entirety as follows:

                 (B)      Liens existing on any real property (including
                 leaseholds) and fixtures thereon (and in the cases of the
                 Liens of the Greeley Indenture and United Cities Indenture,
                 other property covered by the Greeley Indenture as
                 specifically limited by the Tenth Supplemental Indenture or by
                 the United Cities Indenture as specifically limited by the
                 Twenty-Second Supplemental Indenture) at the time of
                 acquisition of such property by Borrower or by such Subsidiary
                 through a merger or consolidation permitted under Section 4.04
                 above, whether or not assumed, or on any such property of a
                 Subsidiary at the time such Subsidiary is acquired by Borrower
                 or another Subsidiary in an acquisition permitted under
                 Section 4.15; provided that every such Lien described in this
                 clause (B) shall apply and attach only to the specific items
                 of property originally subject thereto and fixed improvements
                 constructed thereon (and including repairs thereto and
                 replacements thereof) and any extensions located in the States
                 of Colorado, Kansas, or Missouri of the former Greeley Gas
                 Company system with respect to the Lien of the Greeley
                 Indenture or extensions located in the States of Georgia,
                 Illinois, Iowa, Kansas, Kentucky, Missouri, North Carolina,
                 South Carolina, Tennessee, or Virginia of the former United
                 Cities Gas Company system with respect to the Lien of the
                 United Cities Indenture and shall not extend to any other
                 assets or property whatsoever (including, without limitation,
                 to any property or assets of the acquiring entity or of the
                 other corporation or corporations which are party to the
                 merger or consolidation), other than such assets of the
                 acquired company for so long as the acquired company shall
                 remain a separate corporate entity; and provided further that
                 at no time shall the aggregate principal amount of all Debt
                 secured by Liens described in this clause (B), including
                 without limitation the Liens of the Greeley Indenture





                                       2
<PAGE>   3
                 and United Cities Indenture, exceed 55% of the aggregate cost
                 (including the secured Debt) or fair value (without deducting
                 the secured Debt), whichever is less, of the assets subject
                 thereto (with the lower of cost or fair value to be determined
                 separately with respect to each such asset);

         3.      Except to the extent amended or modified herein, the Agreement
is, and shall continue, in full force and effect in accordance with the terms
and provisions thereof.

         IN WITNESS WHEREOF, the parties hereto have executed this Amendment to
Note Purchase Agreement effective as of the date first written above.


ATMOS ENERGY CORPORATION                JOHN HANCOCK MUTUAL LIFE
                                        INSURANCE COMPANY


By: /s/ LARRY J. DAGLEY                 By: /s/ MARILYN O. BOSS
    -------------------                     -------------------
    Larry J. Dagley                     Printed/Typed Name:  Marilyn O. Boss
    Executive Vice President and        Title: Investment Officer
    Chief Financial Officer





                                       3

<PAGE>   1
                                                                  EXHIBIT 4.5(c)

                      AMENDMENT TO NOTE PURCHASE AGREEMENT

         THIS AMENDMENT TO NOTE PURCHASE AGREEMENT is made and entered into as
of the 22nd day of December, 1993 by and between ATMOS ENERGY CORPORATION, a
Texas corporation (the "Company"), and THE VARIABLE ANNUITY LIFE INSURANCE
COMPANY, a Texas life insurance company ("Purchaser").

                              W I T N E S S E T H:

         WHEREAS, the Company and Purchaser entered into that certain Note
Purchase Agreement dated as of August 29, 1991, as amended by an Amendment to
Note Purchase Agreement dated November 26, 1991 (such Note Purchase Agreement
as amended being hereinafter referred to as the "Agreement"), pursuant to which
the Company sold to Purchaser certain of its 9.57% Senior Notes in an aggregate
principal amount of $20,000,000; and

         WHEREAS, the Company and Purchaser now desire to amend the Agreement
in the manner hereinafter set forth;

         NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

         1.      Section 1.2 of the Agreement shall be, and hereby is, amended
by adding the following definitions therein:

         "Tenth Supplemental Indenture" means that certain Tenth Supplemental
         Indenture dated as of December 1, 1993 between the Company and
         Colorado National Bank (formerly Central Bank Denver, National
         Association).

         "Greeley Indenture" means the Indenture of Mortgage and Deed of Trust
         dated as of March 1, 1957 between Greeley Gas Company and the Central
         Bank and Trust Company, as Trustee, as supplemented by the First
         through Tenth Supplemental Indentures thereto (the obligations of
         Greeley Gas Company and its successors under the Greeley Indenture and
         under the bonds issued pursuant thereto having been assumed by the
         Company under the First Amendment to Bond Purchase


                                     -1-
<PAGE>   2
         Agreement dated as of December 1, 1993, between the Company and First
         Colony Life Insurance Company).

         2.      Paragraph (ii) of Section 4.10(b) of the Agreement shall be,
and hereby is, amended to read in its entirety as follows:

         (ii)  Liens existing on any real property (including leaseholds) and
         fixtures thereon (and in the cases of the Liens of the Western
         Kentucky Indenture and Greeley Indenture, other property covered by
         the Western Kentucky Indenture as specifically limited by the Twelfth
         Supplemental Indenture or by the Greeley Indenture as specifically
         limited by the Tenth Supplemental Indenture) at the time of
         acquisition of such property by the Company or by such Subsidiary
         through a merger or consolidation permitted under Section 4.4 above,
         whether or not assumed, or on any such property of a Subsidiary at the
         time such Subsidiary is acquired by the Company or another Subsidiary
         in an acquisition permitted under Section 4.15; provided that every
         such Lien described in this clause (ii) shall apply and attach only to
         the specific items of property originally subject thereto and fixed
         improvements constructed thereon (and including repairs thereto and
         replacements thereof) and any extensions located entirely in the State
         of Kentucky of the former Western Kentucky Gas Utility Corporation
         system with respect to the Lien of the Western Kentucky Indenture or
         extensions located in the States of Colorado, Kansas, or Missouri of
         the former Greeley Gas Company system with respect to the Lien of the
         Greeley Indenture and shall not extend to any other assets or property
         whatsoever (including, without limitation, to any property or assets
         of the acquiring entity or of the other corporation or corporations
         which are party to the merger or consolidation), other than such
         assets of the acquired company for so long as the acquired company
         shall remain a separate corporate entity; and provided further that at
         no time shall the aggregate principal amount of all Debt secured by
         Liens described in this clause (ii), including without limitation the
         Liens of the Western Kentucky Indenture and Greeley Indenture, exceed
         55% of the aggregate cost (including the secured Debt) or fair value
         (without deducting the secured Debt), whichever is less, of the assets
         subject thereto (with the lower of cost or fair value to be determined
         separately with respect to each such asset);

         3.      Except to the extent amended or modified herein, the Agreement
is, and shall continue, in full force and effect in accordance with the terms
and provisions thereof.





                                      -2-
<PAGE>   3
         IN WITNESS WHEREOF, the parties hereto have executed this Amendment to
Note Purchase Agreement effective as of the date first written above.


ATMOS ENERGY CORPORATION                THE VARIABLE ANNUITY LIFE
                                        INSURANCE COMPANY


By: /s/ JAMES F. PURSER                 By: /s/ JULIA S. TUCKER
    -------------------                     -------------------
    James F. Purser                             Julia S. Tucker
    Executive Vice President                    Investment Officer
    and Chief Financial Officer





                                      -3-

<PAGE>   1
                                                                 EXHIBIT 4.5(d)

                      AMENDMENT TO NOTE PURCHASE AGREEMENT


         THIS AMENDMENT TO NOTE PURCHASE AGREEMENT is made and entered into as
of the 29th day of July, 1997 by and between ATMOS ENERGY CORPORATION, a Texas
corporation ("Company"), and THE VARIABLE ANNUITY LIFE INSURANCE COMPANY, a
Texas life insurance company ("Purchaser").

                              W I T N E S S E T H:

         WHEREAS, the Company and Purchaser entered into that certain Note
Purchase Agreement dated as of August 29, 1991, as amended (such Note Purchase
Agreement as amended being hereinafter referred to as the "Agreement"),
pursuant to which the Company sold to Purchaser certain of its 9.57% Senior
Notes in an aggregate principal amount of $20,000,000; and

         WHEREAS, the Company and Purchaser now desire to amend the Agreement
in the manner hereinafter set forth;

         NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

         1.      Section 1.2 of the Agreement shall be, and hereby is, amended
by adding the following definitions therein:

                 "Twenty-Second Supplemental Indenture" means that certain
                 Twenty-Second Supplemental Indenture dated as of July 29, 1997
                 between the Company and First Trust National Association  (as
                 successor to Bank of America Illinois, Continental Bank, N.A.,
                 and City National Bank and Trust Company of Chicago) and
                 Russell C. Bergman (as successor to M.J. Kruger and R. Emmett
                 Hanley).


                                      1
<PAGE>   2
                 "United Cities Indenture" means the Indenture of Mortgage
                 dated as of July 15, 1959 between United Cities Gas Company
                 and City National Bank and Trust Company of Chicago and R.
                 Emmett Hanley, as Trustees, as supplemented by the First
                 through Twenty-Second Supplemental Indentures thereto (the
                 obligations of United Cities Gas Company and its successors
                 under the United Cities Indenture and under the bonds issued
                 pursuant thereto having been assumed by the Company under the
                 Twenty-Second Supplemental Indenture).

         2.      Paragraph (ii) of Section 4.10(b) of the Agreement shall be,
and hereby is, amended to read in its entirety as follows:

                 (ii)     Liens existing on any real property (including
                 leaseholds) and fixtures thereon (and in the cases of the
                 Liens of the Greeley Indenture and United Cities Indenture,
                 other property covered by the Greeley Indenture as
                 specifically limited by the Tenth Supplemental Indenture or by
                 the United Cities Indenture as specifically limited by the
                 Twenty-Second Supplemental Indenture) at the time of
                 acquisition of such property by the Company or by such
                 Subsidiary through a merger or consolidation permitted under
                 Section 4.4 above, whether or not assumed, or on any such
                 property of a Subsidiary at the time such Subsidiary is
                 acquired by the Company or another Subsidiary in an
                 acquisition permitted under Section 4.15; provided that every
                 such Lien described in this clause (ii) shall apply and attach
                 only to the specific items of property originally subject
                 thereto and fixed improvements constructed thereon (and
                 including repairs thereto and replacements thereof) and any
                 extensions located in the States of Colorado, Kansas, or
                 Missouri of the former Greeley Gas Company system with respect
                 to the Lien of the Greeley Indenture or extensions located in
                 the States of Georgia, Illinois, Iowa, Kansas, Kentucky,
                 Missouri, North Carolina, South Carolina, Tennessee, or
                 Virginia of the former United Cities Gas Company system with
                 respect to the Lien of the United Cities Indenture and shall
                 not extend to any other assets or property whatsoever
                 (including, without limitation, to any property or assets of
                 the acquiring entity or of the other corporation or
                 corporations which are party to the merger or consolidation),
                 other than such assets of the acquired company for so long as
                 the acquired company shall remain a separate corporate entity;
                 and provided further that at no time shall the aggregate
                 principal amount of all Debt secured by Liens described in
                 this clause (ii), including without limitation the Liens of
                 the Greeley Indenture and





                                       2
<PAGE>   3
                 United Cities Indenture, exceed 55% of the aggregate cost
                 (including the secured Debt) or fair value (without deducting
                 the secured Debt), whichever is less, of the assets subject
                 thereto (with the lower of cost or fair value to be determined
                 separately with respect to each such asset);

         3.      Except to the extent amended or modified herein, the Agreement
is, and shall continue, in full force and effect in accordance with the terms
and provisions thereof.

         IN WITNESS WHEREOF, the parties hereto have executed this Amendment to
Note Purchase Agreement effective as of the date first written above.


ATMOS ENERGY CORPORATION                THE VARIABLE ANNUITY LIFE
                                        INSURANCE COMPANY


By: /s/ LARRY J. DAGLEY                 By: /s/ JULIA S. TUCKER
    ------------------                      -------------------
    Larry J. Dagley                     Printed/Typed Name: Julia S. Tucker
    Executive Vice President and        Title: Investment Officer 
    Chief Financial Officer





                                       3

<PAGE>   1
                                                                 EXHIBIT 4.6(b)

                      AMENDMENT TO NOTE PURCHASE AGREEMENT

         THIS AMENDMENT TO NOTE PURCHASE AGREEMENT is made and entered into as
of the 22nd day of December, 1993 by and between ATMOS ENERGY CORPORATION, a
Texas corporation (the "Company"), and THE VARIABLE ANNUITY LIFE INSURANCE
COMPANY, a Texas life insurance company ("Purchaser").

                              W I T N E S S E T H:

         WHEREAS, the Company and Purchaser entered into that certain Note
Purchase Agreement dated as of August 31, 1992, (such Note Purchase Agreement
being hereinafter referred to as the "Agreement"), pursuant to which the
Company sold to Purchaser certain of its 7.95% Senior Notes in an aggregate
principal amount of $10,000,000; and

         WHEREAS, the Company and Purchaser now desire to amend the Agreement
in the manner hereinafter set forth;

         NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

         1.      Section 1.2 of the Agreement shall be, and hereby is, amended
by adding the following definitions therein:

         Tenth Supplemental Indenture" means that certain Tenth Supplemental
         Indenture dated as of December 1, 1993 between the Company and
         Colorado National Bank (formerly Central Bank Denver, National
         Association).

         Greeley Indenture" means the Indenture of Mortgage and Deed of Trust
         dated as of March 1, 1957 between Greeley Gas Company and the Central
         Bank and Trust Company, as Trustee, as supplemented by the First
         through Tenth Supplemental Indentures thereto (the obligations of
         Greeley Gas Company and its successors under the Greeley Indenture and
         under the bonds issued pursuant thereto having been assumed by the
         Company under the First Amendment to Bond Purchase Agreement dated as
         of December 1, 1993, between the Company and First Colony Life
         Insurance Company).


                                     -1-
<PAGE>   2
         2.      Paragraph (ii) of Section 4.10(b) of the Agreement shall be,
and hereby is, amended to read in its entirety as follows:

         (ii)  Liens existing on any real property (including leaseholds) and
         fixtures thereon (and in the cases of the Liens of the Western
         Kentucky Indenture and Greeley Indenture, other property covered by
         the Western Kentucky Indenture as specifically limited by the Twelfth
         Supplemental Indenture or by the Greeley Indenture as specifically
         limited by the Tenth Supplemental Indenture) at the time of
         acquisition of such property by the Company or by such Subsidiary
         through a merger or consolidation permitted under Section 4.4 above,
         whether or not assumed, or on any such property of a Subsidiary at the
         time such Subsidiary is acquired by the Company or another Subsidiary
         in an acquisition permitted under Section 4.15; provided that every
         such Lien described in this clause (ii) shall apply and attach only to
         the specific items of property originally subject thereto and fixed
         improvements constructed thereon (and including repairs thereto and
         replacements thereof) and any extensions located entirely in the State
         of Kentucky of the former Western Kentucky Gas Utility Corporation
         system with respect to the Lien of the Western Kentucky Indenture or
         extensions located in the States of Colorado, Kansas, or Missouri of
         the former Greeley Gas Company system with respect to the Lien of the
         Greeley Indenture and shall not extend to any other assets or property
         whatsoever (including, without limitation, to any property or assets
         of the acquiring entity or of the other corporation or corporations
         which are party to the merger or consolidation), other than such
         assets of the acquired company for so long as the acquired company
         shall remain a separate corporate entity; and provided further that at
         no time shall the aggregate principal amount of all Debt secured by
         Liens described in this clause (ii), including without limitation the
         Liens of the Western Kentucky Indenture and Greeley Indenture, exceed
         55% of the aggregate cost (including the secured Debt) or fair value
         (without deducting the secured Debt), whichever is less, of the assets
         subject thereto (with the lower of cost or fair value to be determined
         separately with respect to each such asset);

         3.      Except to the extent amended or modified herein, the Agreement
is, and shall continue, in full force and effect in accordance with the terms
and provisions thereof.





                                      -2-
<PAGE>   3
         IN WITNESS WHEREOF, the parties hereto have executed this Amendment to
Note Purchase Agreement effective as of the date first written above.


ATMOS ENERGY CORPORATION                THE VARIABLE ANNUITY LIFE
                                        INSURANCE COMPANY


By: /s/ JAMES F. PURSER                 By: /s/ JULIA S. TUCKER
    -------------------                     -------------------
    James F. Purser                             Julia S. Tucker
    Executive Vice President                    Investment Officer
    and Chief Financial Officer





                                      -3-

<PAGE>   1
                                                                 EXHIBIT 4.6 (c)

                      AMENDMENT TO NOTE PURCHASE AGREEMENT


         THIS AMENDMENT TO NOTE PURCHASE AGREEMENT is made and entered into as
of the 29th day of July, 1997 by and between ATMOS ENERGY CORPORATION, a Texas
corporation ("Company"), and THE VARIABLE ANNUITY LIFE INSURANCE COMPANY, a
Texas life insurance company ("Purchaser").

                              W I T N E S S E T H:

         WHEREAS, the Company and Purchaser entered into that certain Note
Purchase Agreement dated as of August 31, 1992, as amended by an Amendment to
Note Purchase Agreement dated December 22, 1993 (such Note Purchase Agreement
as amended being hereinafter referred to as the "Agreement"), pursuant to which
the Company sold to Purchaser certain of its 7.95% Senior Notes in an aggregate
principal amount of $10,000,000; and

         WHEREAS, the Company and Purchaser now desire to amend the Agreement
in the manner hereinafter set forth;

         NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

         1.      Section 1.2 of the Agreement shall be, and hereby is, amended
by adding the following definitions therein:

                 "Twenty-Second Supplemental Indenture" means that certain
                 Twenty-Second Supplemental Indenture dated as of July 29, 1997
                 between the Company and First Trust National Association (as
                 successor to Bank of America Illinois, Continental Bank, N.A.,
                 and City National Bank and Trust Company of Chicago) and
                 Russell C. Bergman (as successor to M.J. Kruger and R. Emmett
                 Hanley).


                                      1
<PAGE>   2
                 "United Cities Indenture" means the Indenture of Mortgage
                 dated as of July 15, 1959 between United Cities Gas Company
                 and City National Bank and Trust Company of Chicago and R.
                 Emmett Hanley, as Trustees, as supplemented by the First
                 through Twenty-Second Supplemental Indentures thereto (the
                 obligations of United Cities Gas Company and its successors
                 under the United Cities Indenture and under the bonds issued
                 pursuant thereto having been assumed by the Company under the
                 Twenty-Second Supplemental Indenture).

         2.      Paragraph (ii) of Section 4.10(b) of the Agreement shall be,
and hereby is, amended to read in its entirety as follows:

                 (ii)     Liens existing on any real property (including
                 leaseholds) and fixtures thereon (and in the cases of the
                 Liens of the Greeley Indenture and United Cities Indenture,
                 other property covered by the Greeley Indenture as
                 specifically limited by the Tenth Supplemental Indenture or by
                 the United Cities Indenture as specifically limited by the
                 Twenty-Second Supplemental Indenture) at the time of
                 acquisition of such property by the Company or by such
                 Subsidiary through a merger or consolidation permitted under
                 Section 4.4 above, whether or not assumed, or on any such
                 property of a Subsidiary at the time such Subsidiary is
                 acquired by the Company or another Subsidiary in an
                 acquisition permitted under Section 4.15; provided that every
                 such Lien described in this clause (ii) shall apply and attach
                 only to the specific items of property originally subject
                 thereto and fixed improvements constructed thereon (and
                 including repairs thereto and replacements thereof) and any
                 extensions located in the States of Colorado, Kansas, or
                 Missouri of the former Greeley Gas Company system with respect
                 to the Lien of the Greeley Indenture or extensions located in
                 the States of Georgia, Illinois, Iowa, Kansas, Kentucky,
                 Missouri, North Carolina, South Carolina, Tennessee, or
                 Virginia of the former United Cities Gas Company system with
                 respect to the Lien of the United Cities Indenture and shall
                 not extend to any other assets or property whatsoever
                 (including, without limitation, to any property or assets of
                 the acquiring entity or of the other corporation or
                 corporations which are party to the merger or consolidation),
                 other than such assets of the acquired company for so long as
                 the acquired company shall remain a separate corporate entity;
                 and provided further that at no time shall the aggregate
                 principal amount of all Debt secured by Liens described in
                 this clause (ii), including without limitation the Liens of
                 the Greeley Indenture and





                                       2
<PAGE>   3
                 United Cities Indenture, exceed 55% of the aggregate cost
                 (including the secured Debt) or fair value (without deducting
                 the secured Debt), whichever is less, of the assets subject
                 thereto (with the lower of cost or fair value to be determined
                 separately with respect to each such asset);

         3.      Except to the extent amended or modified herein, the Agreement
is, and shall continue, in full force and effect in accordance with the terms
and provisions thereof.

         IN WITNESS WHEREOF, the parties hereto have executed this Amendment to
Note Purchase Agreement effective as of the date first written above.

ATMOS ENERGY CORPORATION                THE VARIABLE ANNUITY LIFE
                                        INSURANCE COMPANY


By: /s/ LARRY J. DAGLEY                 By: /s/ JULIA S. TUCKER
    -------------------                     -------------------
    Larry J. Dagley                     Printed/Typed Name:  Julia S. Tucker
    Executive Vice President and        Title: Investment Officer 
    Chief Financial Officer 





                                       3

<PAGE>   1
                                                                 EXHIBIT 4.7(b)

                      AMENDMENT TO NOTE PURCHASE AGREEMENT


         THIS AMENDMENT TO NOTE PURCHASE AGREEMENT is made and entered into as
of the 29th day of July, 1997 by and between ATMOS ENERGY CORPORATION, a Texas
corporation ("Company"), and NEW YORK LIFE INSURANCE COMPANY, a New York mutual
life insurance company, NEW YORK LIFE INSURANCE AND ANNUITY CORPORATION, a
Delaware corporation, THE VARIABLE ANNUITY LIFE INSURANCE COMPANY, a Texas life
insurance company, AMERICAN GENERAL LIFE INSURANCE COMPANY, a Texas life
insurance company, and MERIT LIFE INSURANCE COMPANY, a Texas life insurance
company (each a "Purchaser", collectively the "Purchasers").

                              W I T N E S S E T H:

         WHEREAS, the Company and the Purchasers entered into that certain Note
Purchase Agreement dated as of November 14, 1994, (such Note Purchase Agreement
being hereinafter referred to as the "Agreement"), pursuant to which the
Company sold to the Purchasers certain of its 8.07% Senior Notes in an
aggregate principal amount of $20,000,000 and certain of its 8.26% Senior Notes
in the aggregate amount of $20,000,000; and

         WHEREAS, the Company and the Purchasers now desire to amend the
Agreement in the manner hereinafter set forth;

         NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

         1.      Section 1.2 of the Agreement shall be, and hereby is, amended
by adding the following definitions therein:


                                      1
<PAGE>   2
                 "Twenty-Second Supplemental Indenture" means that certain
                 Twenty-Second Supplemental Indenture dated as of July 29, 1997
                 between the Company and First Trust National Association (as
                 successor to Bank of America Illinois, Continental Bank, N.A.,
                 and National Bank and Trust Company of Chicago) and Russell C.
                 Bergman (as successor to M.J. Kruger and R. Emmett Hanley).

                 "United Cities Indenture" means the Indenture of Mortgage
                 dated as of July 15, 1959 between United Cities Gas Company
                 and City National Bank and Trust Company of Chicago and R.
                 Emmett Hanley, as Trustees, as supplemented by the First
                 through Twenty-Second Supplemental Indentures thereto (the
                 obligations of United Cities Gas Company and its successors
                 under the United Cities Indenture and under the bonds issued
                 pursuant thereto having been assumed by the Company under the
                 Twenty-Second Supplemental Indenture).

         2.      Paragraph (ii) of Section 4.10(b) of the Agreement shall be,
and hereby is, amended to read in its entirety as follows:

                 (ii)     Liens existing on any real property (including
                 leaseholds) and fixtures thereon (and, in the cases of the
                 Liens of the Greeley Indenture and United Cities Indenture,
                 other property covered by the Greeley Indenture or by the
                 United Cities Indenture as described therein) at the time of
                 acquisition of such property by the Company or by such
                 Subsidiary through a merger or consolidation permitted under
                 Section 4.4 above, whether or not assumed, or on any such
                 property of a Subsidiary at the time such Subsidiary is
                 acquired by the Company or another Subsidiary in an
                 acquisition permitted under Section 4.15; provided, however,
                 that every such Lien described in this clause (ii) shall apply
                 and attach only to the specific items of property originally
                 subject thereto and fixed improvements constructed thereon
                 (and including repairs thereto and replacements thereof) and
                 any extensions and other acquired properties as are subject to
                 the Lien of the Greeley Indenture or to the Lien of the United
                 Cities Indenture as set forth therein and shall not extend to
                 any other assets or property whatsoever (including, without
                 limitation, to any property or assets of the acquiring entity
                 or of the other corporation or corporations which are party to
                 the merger or consolidation), other than such assets of the
                 acquired company for so long as the acquired company shall
                 remain a separate corporate entity; and provided further that
                 at no time shall the aggregate principal amount of all Debt
                 secured by Liens described in this clause (ii), including,
                 without limitation, the Liens of the Greeley Indenture and





                                       2
<PAGE>   3
                 United Cities Indenture, exceed 55% of the aggregate cost
                 (including the secured Debt) or fair value (without deducting
                 the secured Debt), whichever is less, of the assets subject
                 thereto (with the lower of cost or fair value to be determined
                 separately with respect to each such asset);

         3.      Except to the extent amended or modified herein, the Agreement
is, and shall continue, in full force and effect in accordance with the terms
and provisions thereof.

         4.      This Agreement may be executed in multiple counterparts, all
of which shall constitute one instrument.

         IN WITNESS WHEREOF, the parties hereto have executed this Amendment to
Note Purchase Agreement effective as of the date first written above.

ATMOS ENERGY CORPORATION                NEW YORK LIFE INSURANCE COMPANY


By: /s/ LARRY J. DAGLEY                 By: /s/ LISA A. SCUDERI
    -------------------                     -------------------
    Larry J. Dagley                     Printed/Typed Name: Lisa A. Scuderi 
    Executive Vice President and        Title: Investment Manager 
    Chief Financial Officer

                                        NEW YORK LIFE INSURANCE AND
                                        ANNUITY CORPORATION
                                        By:  NEW YORK LIFE INSURANCE COMPANY

                                        By: /s/ LISA A. SCUDERI
                                            -------------------
                                        Printed/Typed Name: Lisa A. Scuderi 
                                        Title: Investment Manager 
                                        





                                       3
<PAGE>   4
                                        THE VARIABLE ANNUITY LIFE
                                        INSURANCE COMPANY


                                        By: /s/ JULIA S. TUCKER
                                            -------------------
                                        Printed/Typed Name: Julia S. Tucker 
                                        Title: Investment Officer 
                                        

                                        AMERICAN GENERAL LIFE INSURANCE
                                        COMPANY


                                        By: /s/ JULIA S. TUCKER
                                            -------------------
                                        Printed/Typed Name: Julia S. Tucker 
                                        Title: Investment Officer 
                                        


                                        MERIT LIFE INSURANCE COMPANY


                                        By: /s/ JULIA S. TUCKER
                                            -------------------
                                        Printed/Typed Name: Julia S. Tucker 
                                        Title: Investment Officer 





                                       4

<PAGE>   1
                                                                     EXHIBIT 5.1


    [Letterhead of Locke Purnell Rain Harrell (A Professional Corporation)]




                               April 20, 1998
                                    

Atmos Energy Corporation
1800 Three Lincoln Centre
5430 LBJ Freeway
Dallas, TX 75240

Ladies and Gentlemen:

     We have acted as counsel for Atmos Energy Corporation, a Texas and Virginia
corporation (the "Company"), in connection with the Registration Statement on
Form S-3 (the "Registration Statement"), filed by the Company with the
Securities and Exchange Commission (the "Commission") under the Securities Act
of 1933, as amended (the "Securities Act"), relating to the proposed issuance
and sale from time to time of up to $150,000,000 in aggregate principal amount
of the Company's debt securities (the "Debt Securities"), each series of which
will be issued under an Indenture (the "Indenture") to be entered into between
the Company and U.S. Bank Trust National Association, as Trustee (the
"Trustee"). 

     In our capacity as your counsel in the connection referred to above, we
have examined the Restated Articles of Incorporation, As Amended, and Amended
and Restated Bylaws of the Company and the form of the Indenture (filed as an
exhibit to the Registration Statement), and have examined the originals, or
copies certified or otherwise identified, of corporate records of the Company,
including minute books of the Company as furnished to us by the Company,
certificates of public officials and of representatives of the Company, statutes
and other instruments or documents, as a basis for the opinions hereinafter
expressed.  In giving such opinions, we have relied upon certificates of
officers of the Company with respect to the accuracy of the material factual
matters contained in such certificates.  In making our examination, we have
assumed that all signatures on documents examined by us are genuine, that all
documents submitted to us as originals are authentic and that all documents
submitted to us as certified or photostatic copies conform with the original
copies of such documents.
<PAGE>   2

Atmos Energy Corporation
April 20, 1998
Page 2

     On the basis of the foregoing, and subject to the assumptions, limitations
and qualifications set forth herein, we are of the opinion that:

     1.   The Company is duly incorporated, validly existing and in good
standing under the laws of the State of Texas and the Commonwealth of Virginia.

     2.   The Company has the corporate power and authority to enter into and
perform the Indenture. The execution, delivery and performance by the Company of
the Indenture has been duly authorized by all requisite corporate action of the
Company and when executed and delivered by the Company will constitute a
valid and legally binding instrument of the Company enforceable against the
Company in accordance with its terms, subject to (x) any applicable bankruptcy,
insolvency, reorganization or other laws relating to or affecting creditors'
rights generally and (y) general principles of equity (regardless of whether
such enforceability is considered in a proceeding in equity or at law).

     3.   The Debt Securities have been duly authorized and, when the final
terms thereof have been duly established and approved and when duly executed by
the Company, in each case pursuant to the authority granted in the Board
Resolutions, and authenticated by the Trustee in accordance with the Indenture
and delivered to and paid for by the purchasers thereof, will constitute valid
and legally binding obligations of the Company entitled to the benefits of the
Indenture, subject to (x) any applicable bankruptcy, insolvency, reorganization
or other laws relating to or affecting creditors' rights generally and (y)
general principles of equity (regardless of whether such enforceability is
considered in a proceeding in equity or at law).

     Our opinions are limited solely to the laws of the State of Texas, the
Virginia Stock Corporation Act of the Commonwealth of Virginia and the United
States federal securities laws, each as presently in effect, insofar as such
laws may govern the matters addressed in these opinions. You should be aware
that we are not admitted to practice law in the Commonwealth of Virginia and any
opinion herein as to the laws of such commonwealth is based solely upon the
latest unofficial compilation of the corporate statutes and case laws of such
commonwealth available to us. To the extent that the laws of any other
jurisdiction (i.e., other than the State of Texas, the Virginia Stock
Corporation Act of the Commonwealth of Virginia or the United States federal
securities laws) govern any matters included in this opinion, no opinion is
expressed herein. In that regard, we note that the Indenture provides that it
and the Debt Securities are governed by the laws of the State of New York. In
providing the opinions expressed herein, we have assumed, with your permission
and without any investigation, that the applicable laws of the State of New York
with respect to the enforceability of the Indenture against the Company are the
same, in all relevant respects, as the laws of the State of Texas. We undertake
no obligation to advise you of facts or changes in law occurring after the date
of this opinion which might affect the opinions expressed herein.

     At your request, this opinion is being furnished to you for filing as
Exhibit 5.1 to the Registration Statement. We hereby consent to the reference to
our Firm under the caption "Legal Matters" in the Registration Statement. In
giving such consent, we do not thereby concede that we are within the category
of persons whose consent is required under Section 7 of the Securities Act or
the rules and regulations of the Commission promulgated thereunder.

                                       Very truly yours,

                                       Locke Purnell Rain Harrell
                                       (A Professional Corporation)


                                       By: /s/ VAN M. JOLAS
                                          --------------------------------------
                                          Van M. Jolas

VMJ:pp

<PAGE>   1
                                                                    EXHIBIT 12.1

                            ATMOS ENERGY CORPORATION
               COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES
                         (Dollar amounts in thousands)


<TABLE>
<CAPTION>
                                                      Quarter Ended 
                                                        December 31                  Year ended September 30
                                                     -----------------   -----------------------------------------------
                                                       1997     1996      1997      1996      1995      1994      1993
- ------------------------------------------------------------------------------------------------------------------------
<S>                                                 <C>         <C>       <C>       <C>       <C>       <C>       <C>    
Income from continuing operations before
     provision for income taxes per statement
     of income                                      $ 32,406    $29,004   $38,136   $64,467   $45,352   $41,242   $45,573
Add
     Portion of rents representative of the
          Interest factor                                849        851     3,507     3,237     3,058     3,113     2,726
     Interest on debt & amort of debt expense          9,309      8,701    33,595    31,677    30,186    28,107    30,393
                                                     -------    -------   -------   -------   -------   -------   -------
               Income as adjusted                   $ 42,564    $38,556   $75,238   $99,381   $78,596   $72,462   $78,692
                                                     =======    =======   =======   =======   =======   =======   =======

Fixed charges
     Interest on debt & amort of debt expense (1)      9,309      8,701    33,595    31,677    30,186    28,107    30,393
     Capitalized interest                     (2)      1,000         79     1,570       376       775       237       325
     Rents                                             2,546      2,553    10,522     9,710     9,175     9,339     8,177
     Portion of rents representative of the
          interest factor                     (3)        849       851      3,507     3,237     3,058     3,113     2,726
                                                     -------   -------    -------   -------   -------   -------   -------
               Fixed charges (1)+(2)+(3)            $ 11,158    $ 9,631   $38,672   $35,290   $34,019   $31,457   $33,444
                                                     =======    =======   =======   =======   =======   =======   =======

     Ratio of earnings to fixed charges                 3.81       4.00      1.95      2.82      2.31      2.30      2.35

</TABLE>

<PAGE>   1
                                                                    EXHIBIT 23.1


                         CONSENT OF INDEPENDENT AUDITOR

We consent to the reference of our firm under the caption "Experts" in the
Registration Statement (Form S-3) and related Prospectus of Atmos Energy
Corporation for the registration of $150,000,000 of debt securities and to the
incorporation by reference therein of our report dated November 11, 1997 with
respect to the consolidated financial statements of Atmos Energy Corporation
included in its Annual Report on Form 10-K for the year ended September 30,
1997, filed with the Securities and Exchange Commission.


                                   /s/ ERNST & YOUNG LLP

Dallas, Texas
April 16, 1998

<PAGE>   1
                                                                EXHIBIT 23.2


                   CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS


As independent public accountants, we hereby consent to the incorporation by
reference in this Form S-3 of Atmos Energy Corporation of our report dated
February 14, 1997 appearing in the Annual Report on Form 10-K for the year
ended December 31, 1996 of United Cities Gas Company.

                                             /s/ ARTHUR ANDERSEN LLP
                                             -----------------------
                                                 Arthur Andersen LLP

Nashville, Tennessee
April 16, 1998

<PAGE>   1
                                                                    EXHIBIT 25.1

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

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

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

                                    FORM T-1

                         STATEMENT OF ELIGIBILITY UNDER
                      THE TRUST INDENTURE ACT OF 1939 OF A
                    CORPORATION DESIGNATED TO ACT AS TRUSTEE
              Check if an Application to Determine Eligibility of
                    a Trustee Pursuant to Section 305(b)(2) 
                                                            ---
           ----------------------------------------------------------

                      U.S. BANK TRUST NATIONAL ASSOCIATION
              (Exact name of Trustee as specified in its charter)

<TABLE>
  <S>                                               <C>             <C>
  111 EAST WACKER DRIVE, SUITE 3000
        CHICAGO, ILLINOIS                            60601                    36-4046888
(Address of principal executive offices)           (Zip Code)       I.R.S. Employer Identification No.
</TABLE>

                                 R. C. Bergman
                       111 East Wacker Drive, Suite 3000
                            Chicago, Illinois 60601
                            Telephone (312) 228-9421
          (Name, address and telephone number of agent for service)

                            ATMOS ENERGY CORPORATION
              (Exact name of obligor as specified in its charter)

<TABLE>
<S>                                                                     <C>
                   TEXAS AND VIRGINIA                                                75-1743247
(State or other jurisdiction of incorporation or organization)          (I.R.S. Employer Identification No.)
</TABLE>

1800 THREE LINCOLN CENTRE 
5430 LBJ FREEWAY 
DALLAS, TEXAS                                                         75240 
(Address of Principal Executive Offices)                            (Zip Code)

                                DEBT SECURITIES
                      (Title of the Indenture Securities)

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

<PAGE>   2
                                   FORM T-1 

ITEM 1. GENERAL INFORMATION. Furnish the following information as to the
        Trustee.

         a) Name and address of each examining or supervising authority to
            which it is subject.
            Comptroller of the Currency 
            Washington, D.C.

         b) Whether it is authorized to exercise corporate trust powers. 
            Yes

ITEM 2.  AFFILIATIONS WITH OBLIGOR. If the obligor is an affiliate of the
         Trustee, describe each such affiliation. 
            None

ITEMS 13.        There is not nor has there been a default with respect to the 
                 securities under this Indenture. The Trustee is a Trustee under
                 other Indentures under which securities issued by the obligor
                 are outstanding. There is not and there has not been a default
                 with respect to the securities outstanding under such other
                 Indentures. 

ITEM 16. LIST OF EXHIBITS: List below all exhibits filed as a part of this 
         statement of eligibility and qualification.

         1.      A copy of the Articles of Association of the Trustee now in
                 effect, incorporated herein by reference to Exhibit 1 of Form
                 T-1, Registration No. 333-18235.

         2.      A copy of the certificate of authority of the Trustee to
                 commence business, incorporated herein by reference to Exhibit
                 2 of Form T-1, Registration No. 333-18235.

         3.      A copy of the certificate of authority of the Trustee to
                 exercise corporate trust powers, incorporated herein by
                 reference to Exhibit 3 of Form T-1, Registration 
                 No. 333-18235.

         4.      A copy of the existing bylaws of the Trustee, as now in
                 effect, incorporated herein by reference to Exhibit 4 of Form
                 T-1, Registration No. 333-18235.

         5.      Not applicable.

         6.      The consent of the Trustee required by Section 321(b) of the
                 Trust Indenture Act of 1939, incorporated herein by reference
                 to Exhibit 6 of Form T-1, Registration No. 333-18235.

         7.      A copy of the latest report of condition of the Trustee
                 published pursuant to law or the requirements of its
                 supervising or examining authority, filed herewith.

         8.      Not applicable.

         9.      Not applicable.





                                      2
<PAGE>   3

                                   SIGNATURE

         Pursuant to the requirements of the Trust Indenture Act of 1939, as
         amended, the Trustee, U.S. BANK TRUST NATIONAL ASSOCIATION, a national
         banking association organized and existing under the laws of the
         United States of America, has duly caused this statement of
         eligibility and qualification to be signed on its behalf by the
         undersigned, thereunto duly authorized, all in the City of Chicago,
         State of Illinois on the 17th day of April, 1998.

                                         U.S. BANK TRUST NATIONAL ASSOCIATION

                                         By: /s/ R. C. Bergman
                                             -----------------------------------
                                             R. C. Bergman
                                             Vice President and Assistant 
                                             Secretary










                                      3
<PAGE>   4
CONSOLIDATED REPORT OF CONDITION FOR INSURED COMMERCIAL
AND STATE-CHARTERED SAVINGS BANKS FOR DECEMBER 31, 1997

All schedules are to be reported in thousands of dollars.  Unless otherwise
indicated, report the amount outstanding as of the last business day of the
quarter.

SCHEDULE RC - BALANCE SHEET
<TABLE>
<CAPTION>
                                                                                                                  C200   (-
                                                                                                Dollar Amounts in Thousands
- --------------------------------------------------------------------------------------------------------------------------- 
<S>                                                                                              <C>       <C>        <C>
                                                                                                 RCON
ASSETS                                                                                           ----
 1. Cash and balances due from depository institutions (from Schedule RC-A):
    a. Noninterest-bearing balances and currency and coin(1) ...................................  0081. .     55,536   1.a.
    b. Interest-bearing balances(2) ............................................................  0071. .          0   1.b.
 2. Securities:
    a. Held-to-maturity securities (from Schedule RC-B, column A) ..............................  1754. .          0   2.a.
    b. Available-for-sale securities (from Schedule RC-B, column D) ............................  1773. .      3,216   2.b.
 3. Federal funds sold and securities purchased under agreements to resell......................  1350. .          0   3.
 4. Loans and lease financing receivables:                                      RCON
                                                                                ----
    a. Loans and leases, net of unearned income (from Schedule RC-C) .........  2122. .      0           . . . . . .   4.a.
    b. LESS: Allowance for loan and lease losses .............................  3123. .      0           . . . . . .   4.b.
    c. LESS: Allocated transfer risk reserve .................................  3128. .      0           . . . . . .   4.c.
    d. Loans and leases, net of unearned income,                                     
       allowance, and reserve (item 4.a minus 4.b and 4.c) .....................................  2125. .          0   4.d.
 5. Trading assets .............................................................................  3545. .          0   5.
 6. Premises and fixed assets (including capitalized leases) ...................................  2145. .         95   6.
 7. Other real estate owned (from Schedule RC-M) ...............................................  2150. .          0   7.
 8. Investments in unconsolidated subsidiaries and associated companies (from Schedule RC-M) ...  2130. .          0   8.
 9. Customers' liability to this bank on acceptances outstanding ...............................  2155. .          0   9.
10. Intangible assets (from Schedule RC-M) .....................................................  2143. .     48,072   10.
11. Other assets (from Schedule RC-F) ..........................................................  2160. .      2,435   11.
12. Total assets (sum of items 1 through 11) ...................................................  2170. .    109,354   12.
                                                                                     
</TABLE>
- ---------------
(1) Includes cash items in process of collection and unposted debits.
(2) Includes time certificates of deposit not held for trading.
<PAGE>   5

SCHEDULE RC--CONTINUED
<TABLE>
<CAPTION>
                                                                                               Dollar Amounts in Thousands 
- -------------------------------------------------------------------------------------------------------------------------- 
<S>                                                         <C>            <C>                 <C>     <C>         <C>
LIABILITIES

13. Deposits:
                                                                                                RCON
                                                                                                ----
    a. In domestic offices (sum of totals of columns A and C from Schedule RC-E) .............  2200. .          0  13.a.
                                                            RCON
                                                            ----
       (1) Noninterest-bearing(1) ..........................6631. .          0                          . . . . .   13.a.(1)
       (2) Interest-bearing ................................6636. .          0                          . . . . .   13.a.(2)
    b. In foreign offices, Edge and Agreement subsidiaries, and IBFs .........................          . . . . .   
       (1) Noninterest-bearing ...............................................................  
       (2) Interest-bearing ..................................................................          . . . . .  
14. Federal funds purchased and securities sold under agreements to repurchase ...............  2800. .          0  14.
15. a. Demand notes issued to the U.S. Treasury ..............................................  2840. .          0  15.a 
    b. Trading liabilities ...................................................................  3548. .          0  15.b 
16. Other borrowed money (includes mortgage indebtedness and obligations under
    capitalized leases):
    a. With a remaining maturity of one year or less .........................................  2332. .          0  16.a 
    b. With a remaining maturity of more than one year through three years ...................  A547. .          0  16.b 
    c. With a remaining maturity of more than three years ....................................  A548. .          0  16.c 
17. Not applicable
18. Bank's liability on acceptances executed and outstanding .................................  2920. .          0  18.
19. Subordinated notes and debentures (2) ....................................................  3200. .          0  19.
20. Other liabilities (from Schedule RC-G) ...................................................  2930. .      2,072  20.
21. Total liabilities (sum of items 13 through 20) ...........................................  2948. .      2,072  21.
22. Not applicable

EQUITY CAPITAL
23. Perpetual preferred stock and related surplus ............................................  3838. .          0  23.
24. Common stock .............................................................................  3230. .      1,000  24.
25. Surplus (exclude all surplus related to preferred stock)..................................  3839. .    106,712  25.
26. a. Undivided profits and capital reserves ................................................  3632. .(       430) 26.a.
    b. Net unrealized holding gains (losses) on available-for-sale securities ................  8434. .          0  26.b.
27. Cumulative foreign currency translation adjustments ......................................         . . . . . .     
28. Total equity capital (sum of items 23 through 27) ........................................  3210. .    107,282  28.
29. Total liabilities, and equity capital (sum of items 21 and 28) ...........................  3300. .    109,354  29.
</TABLE>

<TABLE>
<S>                                                                                             <C>            <C>
Memorandum                                                                                                               

To be reported only with the March Report of Condition.
 1. Indicate in the box at the right the number of the statement below that
    best describes the most comprehensive level of auditing work performed 
    for the bank by independent external auditors as of any date during 1996..................  6724. .        N/A  M.1.
</TABLE>

<TABLE>
<S>                                                              <C>
1 = Independent audit of the bank conducted in accordance        4 = Directors' examination of the bank performed by other
    with generally accepted auditing standards by a certified        external auditors (may be required by state chartering
    public accounting firm which submits a report on the bank        authority)
2 = Independent audit of the bank's parent holding company       5 = Review of the bank's financial statements by external
    conducted in accordance with generally accepted auditing         auditors
    standards by a certified public accounting firm which        6 = Compilation of the bank's financial statements by external
    submits a report on the consolidated holding company             auditors
    (but not on the bank separately)                             7 = Other audit procedures (excluding tax preparation work)
3 = Directors' examination of the bank conducted in accordance   8 = No external audit work
    with generally accepted auditing standards by a certified
    public accounting firm (may be required by state 
    chartering authority)
</TABLE>

- ------------
(1) Includes total demand deposits and noninterest-bearing time and savings
    deposits.
(2) Includes limited life preferred stock and related surplus.
<PAGE>   6

SCHEDULE RC-A - CASH AND BALANCES DUE FROM DEPOSITORY INSTITUTIONS

Exclude assets held for trading.

<TABLE>
<CAPTION>
                                                                                                              C205   (-
                                                                                            Dollar Amounts in Thousands
- ----------------------------------------------------------------------------------------------------------------------- 
<S>                                                                                 <C>          <C>              <C>
                                                                                      RCON
                                                                                      ----
1. Cash items in process of collection, unposted debits, and currency and coin:
   a. Cash items in process of collection and unposted debits ......................  0020. .                0      1.a
   b. Currency and coin ............................................................  0080. .                0      1.b
2. Balances due from depository institutions in the U.S.:
   a. U.S. branches and agencies of foreign banks ..................................  0083. .                0      2.a
   b. Other commercial banks in the U.S. and other depository institutions
      in the U.S. (including their IBFs) ...........................................  0085. .           55,536      2.b
3. Balances due from banks in foreign countries and foreign central banks:
   a. Foreign branches of other U.S. banks .........................................  0073. .                0      3.a
   b. Other banks in foreign countries and foreign central banks ...................  0074. .                0      3.b
4. Balances due from Federal Reserve Banks .........................................  0090. .                0      4.
5. Total (sum of items 1 through 4) (must equal 
   Schedule RC, sum of items 1.a and 1.b) ..........................................  0010. .           55,536      5.

<CAPTION>

Memorandum                                                                                     Dollar Amounts in Thousands
- --------------------------------------------------------------------------------------------------------------------------
<S>                                                                                            <C>                     <C>
                                                                                      RCON
                                                                                      ----
1. Noninterest-bearing balances due from commercial banks in the U.S.
   (included in items 2.a and 2.b above) ...........................................  0050. .           55,536      M.1
</TABLE>



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