AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON DECEMBER 24, 1997
                                                     REGISTRATION NO. 333-
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                      SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C. 20549
 
                                ---------------
                                   FORM S-3
                            REGISTRATION STATEMENT
                                     UNDER
                          THE SECURITIES ACT OF 1933
 
                                ---------------
 
                              ENERGEN CORPORATION
            (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)
 
                                ---------------
 
              ALABAMA                               63-0757759
  (STATE OR OTHER JURISDICTION OF      (I.R.S. EMPLOYER IDENTIFICATION NO.)
   INCORPORATION OR ORGANIZATION)
 
                            2101 SIXTH AVENUE NORTH
                           BIRMINGHAM, ALABAMA 35203
                                (205) 326-2700
  (ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE, OF
                   REGISTRANT'S PRINCIPAL EXECUTIVE OFFICES)
 
                                ---------------
                            J. DAVID WOODRUFF, JR.
                              ENERGEN CORPORATION
                            2101 SIXTH AVENUE NORTH
                           BIRMINGHAM, ALABAMA 35203
                                (205) 326-2700
 (NAME, ADDRESS, INCLUDING ZIP CODE AND TELEPHONE NUMBER, INCLUDING AREA CODE,
                                      OF
                              AGENT FOR SERVICE)
 
                                ---------------
 
     THE COMMISSION IS REQUESTED TO SEND COPIES OF ALL COMMUNICATIONS TO:
 
           JOHN K. MOLEN                           DAVID P. FALCK
   BRADLEY ARANT ROSE & WHITE LLP        WINTHROP, STIMSON, PUTNAM & ROBERTS
    2001 PARK PLACE, SUITE 1400                ONE BATTERY PARK PLAZA
     BIRMINGHAM, ALABAMA 35203              NEW YORK, NEW YORK 10004-1490
           (205) 521-8238                          (212) 858-1438
 
                                ---------------
 
  APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC: From time
to time after this Registration Statement becomes effective as the Registrant
may determine.
 
  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 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. [X]
 
                        CALCULATION OF REGISTRATION FEE
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                                        PROPOSED MAXIMUM
        TITLE OF EACH CLASS OF         AGGREGATE OFFERING       AMOUNT OF
     SECURITIES TO BE REGISTERED            PRICE(1)      REGISTRATION FEE(2)(3)
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Debt Securities; Common Stock........     $400,000,000           $108,704

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(1) Estimated solely for purposes of computing the registration fee.
(2) The registration fee has been calculated in accordance with Rule 457(o)
    under the Securities Act of 1933, as amended, and reflects the offering
    price rather than the principal amount of any Debt Securities issued at a
    discount.
(3) Pursuant to Rule 429 under the Securities Act of 1933, as amended,
    $31,512,500 of the securities being registered are being carried forward
    from a prior registration statement on Form S-3 (Registration No. 333-
    11239). The filing fee associated with such securities that was previously
    paid with the earlier registration statement was $10,866.
 
                                ---------------
  Pursuant to Rule 429 under the Securities Act of 1933, as amended, the
Prospectus contained herein also relates to securities of the Registrant
previously registered on Form S-3 (Registration No. 333-11239).
 
  THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATES AS
MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT SHALL FILE A
FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION STATEMENT
SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(A) OF THE
SECURITIES ACT OF 1933 OR UNTIL THE REGISTRATION STATEMENT SHALL BECOME
EFFECTIVE ON SUCH DATE AS THE COMMISSION ACTING PURSUANT TO SAID SECTION 8(A),
MAY DETERMINE.
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                             SUBJECT TO COMPLETION
                   PRELIMINARY PROSPECTUS DATED        , 1998
 
PROSPECTUS
 
                                  $400,000,000
 
                              ENERGEN CORPORATION
 
                                DEBT SECURITIES
                                  COMMON STOCK
 
  Energen Corporation (the "Corporation") may offer from time to time up to an
aggregate amount of $400,000,000 (or the equivalent thereof if any of the
securities offered hereby are denominated in a currency, currency unit or
composite currency other than the U.S. dollar) of (i) its notes, debentures or
other evidences of unsecured indebtedness (the "Debt Securities") in one or
more currencies on terms to be determined at the time of sale and (ii) shares
of its common stock, par value $.01 per share (the "Common Stock"), on terms to
be determined at the time of sale. The Common Stock is referred to herein as
the "Equity Securities," and the Debt Securities and the Equity Securities are
collectively referred to herein as the "Offered Securities." The Offered
Securities may be sold for U.S. Dollars, foreign currencies or foreign currency
units, and the principal of or any interest on the Debt Securities may be
payable in U.S. Dollars, foreign currencies or foreign currency units. The Debt
Securities will rank equally with all other outstanding unsecured senior
indebtedness of the Corporation. The Debt Securities may be issued in one or
more series with the same or various maturities, at par or with an original
issue discount. The Debt Securities of any series may be in registered or
bearer form and may be represented by a single global security registered in
the name of a securities depositary.
 
  When Debt Securities are offered, a supplement to this Prospectus (the
"Prospectus Supplement") will set forth the specific terms of such Debt
Securities, including, where applicable, the specific designation, aggregate
principal amount, authorized denominations, currency or currency unit of
denomination and payment, maturity, interest rate (which may be fixed or
variable) and time of payment of interest, if any, any terms for redemption
(which either may be at the option of the Corporation or the holder), any terms
for sinking fund payments, and information about any listing on a securities
exchange of such Debt Securities. When Equity Securities are offered, a
Prospectus Supplement will set forth the aggregate number of shares offered.
Any Prospectus Supplement will also set forth the initial public offering
price, the net proceeds to the Corporation and other specific terms of the
Offered Securities.
 
  The Offered Securities may be sold to or through underwriters, dealers or
agents, or directly to purchasers. If any agents of the Corporation or any
underwriters are involved in the sale of the Offered Securities, their names,
and any applicable fee, commission or discount arrangements with them will be
set forth in any applicable Prospectus Supplement. See "Plan of Distribution."
No Offered Securities may be sold without delivery of a Prospectus Supplement
describing such series or issue of Offered Securities and the method and the
terms thereof.
 
THESE  SECURITIES HAVE NOT BEEN APPROVED  OR DISAPPROVED BY THE SECURITIES  AND
 EXCHANGE  COMMISSION   OR  ANY  STATE  SECURITIES  COMMISSION  NOR   HAS  THE
  COMMISSION OR ANY  STATE SECURITIES COMMISSION PASSED UPON  THE ACCURACY OR
   ADEQUACY OF  THIS PROSPECTUS.  ANY  REPRESENTATION TO  THE CONTRARY  IS A
    CRIMINAL OFFENSE.
 
                  The date of this Prospectus is       , 1998.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+THE 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 A +
+SOLICITATION OF AN OFFER TO BUY NOR SHALL THERE BE ANY SALE OF THESE          +
+SECURITIES IN ANY JURISDICTION IN WHICH SUCH OFFER, SOLICITATION OR SALE      +
+WOULD BE UNLAWFUL PRIOR TO REGISTRATION OR QUALIFICATION UNDER THE SECURITIES +
+LAWS OF ANY SUCH JURISDICTION.                                                +
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++


 
                             AVAILABLE INFORMATION
 
  The Corporation is subject to the information requirements of the Securities
Exchange Act of 1934, as amended (the "Exchange Act"), and in accordance
therewith, files reports and other information with the Securities and
Exchange Commission (the "Commission"). Reports, proxy and information
statements and other information filed by the Corporation can be inspected and
copied at the public reference facilities maintained by the Commission at 450
Fifth Street, N.W., Washington, D.C. 20549 and at the Commission's regional
offices at 7 World Trade Center, Suite 1300, New York, New York 10048 and 500
West Madison Street, Suite 1400, Chicago, Illinois 60661-2511. Copies of such
material also can be obtained at prescribed rates from the Public Reference
Section of the Commission at its principal office at 450 Fifth Street, N.W.,
Washington, D.C. 20549. The Commission also maintains a web site
(http://www.sec.gov) that contains reports, proxy and information statements
and other information regarding reporting companies, including the
Corporation. The shares of Common Stock of the Corporation are listed on the
New York Stock Exchange, Inc., 20 Broad Street, New York, New York 10005.
Reports, proxy and information statements and other information concerning the
Corporation can be inspected at the offices of that exchange.
 
  The Corporation has filed a Registration Statement on Form S-3 (herein,
together with all exhibits and amendments thereto, called the "Registration
Statement") with the Commission under the Securities Act of 1933, as amended
(the "Securities Act"), with respect to the Offered Securities. This
Prospectus does not contain all of the information included in the
Registration Statement and the exhibits and schedules thereto. For further
information with respect to the Corporation and the Offered Securities,
reference is hereby made to the Registration Statement and the exhibits and
schedules thereto. The registration statement may be inspected without charge
at the offices of the Commission at 450 Fifth Street, N.W., Washington, D.C.
20549, and copies thereof may be obtained from the Public Reference Section of
the Commission at such address at prescribed rates.
 
                INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE
 
  The following documents filed by the Corporation with the Commission are
incorporated by reference in the Prospectus:
 
    (a) The Corporation's Annual Report on Form 10-K for the year ended
  September 30, 1997 filed pursuant to Section 13(a) of the Exchange Act; and
 
    (b) The description of the Corporation's preferred stock purchase rights
  contained in, and the Rights Agreement filed as an exhibit to, the
  Corporation's Registration Statement on Form 8-A, as amended, File No. 1-
  7810, dated August 8, 1988.
 
  All documents filed by the Corporation pursuant to Sections 13(a), 13(c), 14
or 15(d) of the Exchange Act subsequent to the date of this Prospectus and
prior to the termination of the offering of the securities offered hereby
shall be deemed to be incorporated by reference in this Prospectus and to be a
part hereof from the date of filing such documents. Any statement contained in
a document 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 replaces such statement. Any statement so modified or
superseded shall not be deemed, except as so modified or superseded, to
constitute a part of this Prospectus.
 
  The information relating to the Corporation contained in this Prospectus
summarizes, is based upon, or refers to, information and financial statements
contained in one or more of the documents incorporated by reference in this
Prospectus; accordingly, such information contained herein is qualified in its
entirety by reference to such incorporated documents and should be read in
conjunction therewith.
 
                                       2

 
  The Corporation will provide without charge to each person, including any
beneficial owner, to whom a copy of this Prospectus is delivered, upon the
written or oral request of such person, a copy of any and all of the
information that has been incorporated by reference in the Prospectus (not
including exhibits to the information that is incorporated by reference in the
Prospectus unless such exhibits are specifically incorporated by reference
into the information that the Prospectus incorporates). Requests for such
copies should be addressed to Energen Corporation, Investor Relations
Department, 2101 Sixth Avenue North, Birmingham, Alabama 35203 (telephone
number (800) 654-3206 or (205) 326-2634).
 
                              ENERGEN CORPORATION
 
  The Corporation is a diversified energy holding company engaged in natural
gas distribution and oil and natural gas exploration and production
activities. The Corporation's utility subsidiary, Alabama Gas Corporation
("Alagasco"), is the largest natural gas distribution utility in the State of
Alabama. The Corporation's oil and gas exploration and production activities
are conducted by its subsidiary, Taurus Exploration, Inc. and its subsidiary
(collectively "Taurus").
 
  The Corporation's executive offices are located at 2101 Sixth Avenue North,
Birmingham, Alabama 35203, and its telephone number is (205) 326-2700.
 
               CONSOLIDATED RATIOS OF EARNINGS TO FIXED CHARGES
 
  The following are the consolidated ratios of earnings to fixed charges for
each of the periods indicated:
 


                                                        YEAR ENDED SEPTEMBER 30,
                                                        ------------------------
                                                        1997 1996 1995 1994 1993
                                                        ---- ---- ---- ---- ----
                                                             
   Ratio of Earnings to Fixed Charges.................. 2.40 2.91 2.95 3.68 3.01

 
  For purposes of computing the consolidated ratio, earnings represent net
income applicable to Common Stock, plus applicable income taxes and fixed
charges. Fixed charges represent interest expense, capitalized interest and
amortization of debt expense.
 
                                       3

 
                                USE OF PROCEEDS
 
  Except as may otherwise be described or referred to in a Prospectus
Supplement, the Company intends to use the net proceeds from the sale of the
Offered Securities for general corporate purposes, including the Corporation's
working capital needs, the funding of investments in, or extensions of credit
to, its subsidiaries, the possible acquisition of other corporations or their
assets or liabilities, including the acquisition of natural gas and oil
properties and the reduction of short-term or other outstanding indebtedness.
Pending such use, the Corporation may temporarily invest the net proceeds in
investment grade securities. The Corporation may, from time to time, engage in
additional capital financings of a character and in amounts to be determined
by the Corporation in light of its need at such time or times and in light of
prevailing market conditions.
 
                        DESCRIPTION OF DEBT SECURITIES
 
  The following description of the terms of the Debt Securities sets forth
certain general terms and provisions of the Debt Securities to which any
applicable Prospectus Supplement may relate. The particular terms of the Debt
Securities offered by any applicable Prospectus Supplement (the "Offered Debt
Securities") and the extent, if any, to which such general provisions may
apply to the Debt Securities so offered will be described in the Prospectus
Supplement relating to such Offered Debt Securities.
 
  The Debt Securities will be issued under an Indenture (the "Indenture")
between the Corporation and The Bank of New York (the "Trustee"). A copy of
the Indenture is filed as an exhibit to this Registration Statement. The
following summaries of the Debt Securities and the Indenture do not purport to
be complete and are subject to, and are qualified in their entirety by
reference to, all the provisions of the Indenture, including the applicable
definitions therein of certain terms used in this Prospectus. All capitalized
terms not defined in this Prospectus shall have the definitions ascribed to
them in the Indenture. Copies of the Indenture are available for inspection
during normal business hours at the principal office of the Corporation or at
the corporate trust office of the Trustee.
 
GENERAL
 
  The Debt Securities will be direct, unsecured obligations of the Corporation
and will rank pari passu with all outstanding unsecured senior indebtedness of
the Corporation. The Indenture does not limit the aggregate principal amount
of Debt Securities that may be issued thereunder and provides that Debt
Securities may be issued thereunder from time to time in one or more series.
All securities issued under the Indenture will rank equally and ratably with
all other securities to be issued under such Indenture. The Corporation has
previously issued $125,000,000 principal amount of its Medium-Term Notes,
Series A under the Indenture, all of which are outstanding on the date hereof.
 
  The Debt Securities will be obligations exclusively of the Corporation.
Since substantially all of the operations of the Corporation are conducted
through its subsidiaries, principally Alagasco and Taurus, the Corporation's
cash flow and consequently its ability to service debt is dependent upon the
cash flow of its subsidiaries and the payment of funds by those subsidiaries
in the form of dividends.
 
  The Prospectus Supplement and any related Pricing Supplement will describe
certain terms of the Offered Debt Securities, including: (1) the title of the
Offered Debt Securities; (2) any limit on the aggregate principal amount of
the Offered Debt Securities; (3) the date or dates on which the principal of
the Offered Debt Securities is payable; (4) the rate or rates per annum (which
may be fixed or variable) at which the Offered Debt Securities will bear
interest, if any, or any method by which such rate or rates shall be
determined, and the date or dates from which such interest will accrue; (5)
the date or dates on which interest, if any, on the Offered Debt Securities
will be payable and the Regular Record Dates for any such Interest Payment
Dates; (6) each office or agency where the principal of, and premium, if any,
and any interest on the Offered Debt Securities will be payable and may be
surrendered for registration of transfer or exchange; (7) the period or
periods within which,
 
                                       4

 
the price or prices at which, and the terms and conditions upon which the
Offered Debt Securities may be redeemed, in whole or in part, at the option of
the Corporation; (8) the obligation, if any, of the Corporation to redeem or
purchase the Offered Debt Securities pursuant to any sinking fund or similar
provisions or at the option of a Holder thereof and the period or periods
within which, the price or prices at which and the terms and conditions upon
which the Offered Debt Securities will be redeemed or purchased, in whole or
in part, pursuant to any such obligation; (9) whether the Offered Debt
Securities are to be issued in whole or in part in the form of one or more
global notes, and, if so, the identity of the depositary for such global notes
and the terms and conditions, if any, on which interests in such global notes
may be exchanged for the individual securities represented thereby; (10)
whether the Offered Debt Securities are to be issued with original issue
discount within the meaning of section 1273(a) of the Internal Revenue Code of
1986, as amended (the "Code"), and the regulations thereunder and the amount
of such discount; (11) the obligations or instruments which shall be
considered to be Eligible Obligations in respect of Offered Debt Securities
denominated in any currency other than United States Dollars or in a composite
currency, and any additional or alternative provisions for the reinstatement
of the Corporation indebtedness in respect of Offered Debt Securities after
the satisfaction and discharge thereof; (12) any provisions for payment of
additional amounts for taxes, and any provisions for redemption in the event
the Corporation must comply with withholding tax or other tax reporting
requirements in respect of an Offered Debt Security other than a Floating Rate
Security ("Affected Security") or must pay such additional amounts in respect
of any Offered Debt Security; (13) any index used to determine the amount of
payment of principal of, and premium, if any, and any interest on the Offered
Debt Securities; (14) the applicable Overdue Rate, if any; (15) any addition
to, or modification or deletion of, any Events of Default or covenants
provided for with respect to the Offered Debt Securities; (16) if the
principal of or premium, if any, or interest, if any, on the Offered Debt
Securities are to be payable, at the election of the Corporation or a Holder
thereof, in a coin or currency other than that in which the Debt Securities
are stated to be payable, the period or periods within which, and the terms
and conditions upon which, such election may be made; (17) the currency or
currencies, including composite currencies, in which payment of the principal
of and premium, if any, and interest, if any, on the Offered Debt Securities
shall be payable (if other than the currency of the United States); (18) if
the principal of or premium, if any, or interest on the Offered Debt
Securities are to be payable, or are to be payable at the election of the
Corporation or a Holder thereof, in securities or other property, the type and
amount of such securities or other property, or the method by which such
amount shall be determined, and the period or periods within which, and the
terms and conditions upon which, any such election may be made; (19) the
terms, if any, pursuant to which the Offered Debt Securities may be converted
into or exchanged for shares of capital stock or other securities of the
Corporation; and (20) any other terms and provisions of the Offered Debt
Securities which are not inconsistent with the Indenture.
 
  Unless otherwise provided in the Prospectus Supplement or a Pricing
Supplement, the Debt Securities will be issued only in fully registered form,
without coupons, in denominations of $1,000 or any integral multiple thereof.
 
  Debt Securities may be issued as Discount Securities to be sold at a
substantial discount below their principal amount. Discount Securities mean
any Debt Securities issued with "original issue discount" within the meaning
of Section 1273(a) of the Code and the regulations thereunder. Special United
States income tax and other considerations applicable to Discount Securities
will be described in any applicable Prospectus Supplement relating thereto.
Discount Securities may provide for the declaration of acceleration of the
Maturity of an amount less than the principal amount thereof upon the
occurrence of an Event of Default and the continuation thereof.
 
  The Indenture provides that all Debt Securities of any one series need not
be issued at the same time and that the Corporation may, from time to time,
issue additional Debt Securities of a previously issued series. In addition,
the Indenture provides that the Corporation may issue Debt Securities with
terms different from those of any other series of Debt Securities and, within
a series of Debt Securities, terms (such as interest rate or manner in which
interest is calculated, original issue date, redemption provisions and
maturity date) may differ.
 
                                       5

 
CERTAIN CONDITIONS FOR ISSUANCE OF ADDITIONAL INDEBTEDNESS
 
  Pursuant to Section 234 of the Constitution of Alabama of 1901, the bonded
indebtedness of Alabama corporations may not be increased without the consent
of shareholders. The Corporation is presently authorized to issue, without
further shareholder approval, bonded indebtedness in an amount which, when
added to the bonded indebtedness then outstanding, does not exceed the greater
of (i) $750,000,000 or (ii) one hundred fifty percent (150%) of the total
shareholders' equity of the Corporation as reflected in the consolidated
financial statements of the Corporation as of the end of the Corporation's
most recently completed fiscal quarter.
 
GLOBAL NOTES
 
  If the Prospectus Supplement so provides, the Offered Debt Securities of a
series may be issued in whole or in part in the form of one or more Global
Notes that will be deposited with or on behalf of a depositary located in the
United States identified in any applicable Prospectus Supplement relating to
such series. The laws of some jurisdictions require that certain purchasers of
securities take physical delivery of such securities in definitive form. Such
limits and such laws may impair the ability to transfer beneficial interests
in a Global Note. The specific terms of the depositary arrangement with
respect to any Offered Debt Securities of a series will be described in any
applicable Prospectus Supplement relating to such series.
 
PAYMENT AND PAYING AGENTS
 
  Except as may be provided in the applicable Prospectus Supplement, interest,
if any, on each Debt Security payable on each Interest Payment Date will be
paid to the person in whose name such Debt Security is registered as of the
close of business on the Regular Record Date relating to such Interest Payment
Date. However, if there has been a default in the payment of interest on any
Debt Security, such defaulted interest may be payable to the Holder of such
Debt Security as of the close of business on a date selected by the Trustee
not more than 15 days and not less than 10 days prior to the date proposed by
the Corporation for payment of such defaulted interest.
 
  Unless otherwise indicated in any applicable Prospectus Supplement,
principal of, and premium and interest, if any, on the Debt Securities will be
payable at the office of the Trustee designated for such purpose or at any
paying agent maintained by the Corporation for such purpose, except that at
the option of the Corporation payment of any interest may be made (i) by check
mailed to the address of the Person entitled thereto as such address shall
appear in the Security Register, or (ii) by wire transfer to an account
maintained by the Person entitled thereto. The Corporation may appoint one or
more Paying Agents and may remove any Paying Agent, all in its discretion.
 
  The transfer of the Debt Securities may be registered, and the Debt
Securities may be exchanged for other Debt Securities of authorized
denominations and of like tenor and aggregate principal amount at the office
of the Trustee designated for such purpose or at any paying agency maintained
by the Corporation for such purpose. The Corporation may appoint one or more
additional security registrars or transfer agents and may remove any security
registrar or transfer agent, all in its discretion. The applicable Prospectus
Supplement will identify any additional security registrar or transfer agent
appointed.
 
  No service charge will be made for any registration of transfer or exchange
of the Debt Securities, but the Corporation may require payment of a sum
sufficient to cover any tax or other governmental charge payable in connection
therewith. The Corporation will not be required (a) to issue, register the
transfer of or exchange Debt Securities during the period of 15 days prior to
giving any notice of redemption or (b) to issue, register the transfer of or
exchange any Debt Security selected for redemption in whole or in part, except
the unredeemed portion of any Debt Security being redeemed in part.
 
                                       6

 
  All moneys paid by the Corporation to the Trustee or a Paying Agent for the
payment of principal of, and premium, if any, and any interest on any Debt
Securities which remain unclaimed at the end of two years after such
principal, premium or interest shall become due and payable will be repaid,
subject to applicable laws of escheat, to the Corporation, and the Holder of
such Debt Securities will thereafter look only to the Corporation for payment
thereof.
 
REDEMPTION
 
  Any terms for the optional or mandatory redemption of the Offered Debt
Securities will be set forth in the applicable Prospectus Supplement. In
accordance with the terms of the Indenture, Debt Securities will be redeemable
only upon notice, by mail, not less than 30 nor more than 60 days prior to the
date fixed for redemption and, if less than all of the Debt Securities of any
series are to be redeemed, the particular Debt Securities will be selected by
the Security Registrar by such method as the Trustee deems fair and
appropriate.
 
  Any notice of optional redemption may state that such redemption shall be
conditional upon the receipt by the Trustee, on or prior to the date fixed for
such redemption, of money sufficient to pay the principal of and premium and
interest, if any, on such Debt Securities and that if such money has not been
so received, such notice will be of no force or effect and the Corporation
will not be required to redeem such Debt Securities.
 
EVENTS OF DEFAULT
 
  The following are Events of Default under the Indenture with respect to the
Debt Securities of a series: (a) failure to pay any interest on any Debt
Security of that series within 30 days after the same becomes due and payable;
(b) failure to pay the principal of or premium, if any, on any Debt Security
of that series within three business days after the same becomes due and
payable; (c) failure to perform, or breach of, any other covenant or warranty
of the Corporation in the Indenture (other than a covenant or warranty
included in the Indenture solely for the benefit of one or more series of Debt
Securities other than such series), continued for 90 days after written notice
by the Trustee to the Corporation or by the Holders of at least 25% in
principal amount of all Outstanding Debt Securities of such series to the
Corporation and the Trustee as provided in the Indenture; (d) certain events
involving bankruptcy, insolvency, conservatorship, receivership or
reorganization of the Corporation or Alagasco or Taurus, whether voluntary or
involuntary; (e) a default under any other indebtedness of the Corporation or
Alagasco or Taurus or instrument under which there may be issued or by which
there may be secured or evidenced any indebtedness of the Corporation or
Alagasco or Taurus, in each case aggregating in excess of $10,000,000, which
default constitutes a failure to pay any portion of the principal of such
indebtedness when due or results in the acceleration of the maturity of such
indebtedness, unless within a period of 10 days after written notice of such
default has been given to the Corporation by the Trustee or to the Corporation
and the Trustee by the Holders of at least 10% in principal amount of the
Outstanding Debt Securities of any series, such indebtedness has been
discharged or such acceleration has been rescinded or annulled; and (f) any
other Event of Default provided for with respect to Debt Securities of that
series.
 
  Except as described in (d) and (e) above, no Event of Default with respect
to the Debt Securities of one series necessarily constitutes an Event of
Default with respect to the Debt Securities of any other series issued under
the Indenture.
 
REMEDIES
 
  If any Event of Default with respect to the Debt Securities of any series
occurs and is continuing, either the Trustee or the Holders of at least 33% in
aggregate principal amount of all the Outstanding Debt Securities of that
series may declare the principal amount of all the Outstanding Debt Securities
of that series to be due and payable immediately; provided, however, that if
an Event of Default occurs and is continuing with respect to more than one
series of Debt Securities, the Trustee or the Holders of not less than 33% in
aggregate principal amount of the Outstanding Debt Securities of all such
series, considered as one class, may make such declaration of acceleration and
not the Holders of the Debt Securities of any one of such series.
 
 
                                       7

 
  The Holders of a majority in aggregate principal amount of the Outstanding
Debt Securities of each series may, on behalf of all Holders of the Debt
Securities of that series, waive any past default and its consequences under
the Indenture with respect to the Debt Securities of that series, except a
default in the payment of principal or premium or interest, if any, on any
Debt Security of that series, or in respect of a provision of the Indenture
which cannot be amended or modified without the consent of the Holder of each
Outstanding Debt Security of the series affected.
 
  At any time after the declaration of acceleration with respect to Debt
Securities of any series has been made, but before a judgment or decree for
the payment of money due has been obtained, the Event or Events of Default
giving rise to such declaration of acceleration shall, without further act, be
deemed to have been waived, and such declaration and its consequences shall,
without further act, be deemed to have been rescinded and annulled if (a) the
Corporation has paid or deposited with the Trustee a sum sufficient to pay (1)
all overdue interest on all of such Debt Securities; (2) the principal of and
premium, if any, on any of such Debt Securities which have become due
otherwise than by such declaration of acceleration and interest thereon at the
rate or rates prescribed therefor in such Debt Securities; (3) to the extent
that payment of such interest is lawful, interest upon overdue interest at the
rate or rates prescribed therefor in such Debt Securities; (4) all amounts due
to the Trustee under the Indenture; and (b) any other Events of Default with
respect to the Debt Securities of such series, other than the nonpayment of
the principal of such Debt Securities which has become due solely by such
declaration of acceleration, have been cured or waived as provided in the
Indenture.
 
MISCELLANEOUS RIGHTS AND OBLIGATIONS OF TRUSTEE
 
  The Indenture provides that, subject to the duty of the Trustee during the
continuance of an Event of 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 security or
indemnity. Subject to such provisions for the indemnification of the Trustee
and subject to certain other limitations, the Holders of a majority in
aggregate principal amount of the Outstanding Debt 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 Debt Securities of that
series; provided, however, that if an Event of Default occurs and is
continuing with respect to more than one series of Debt Securities, the
Holders of a majority in aggregate principal amount of the outstanding Debt
Securities of all such series, considered as one class, will have the right to
make such direction, and not the Holders of the Debt Securities of any one of
such series; and provided, further, that (a) such direction will not be in
conflict with any rule of law or with the Indenture and would not involve the
Trustee in personal liability in circumstances where reasonable indemnity
would not, in the Trustee's sole discretion, be adequate, (b) the Trustee
shall not have determined that the action so directed would be unjustly
prejudicial to the Holders not taking part in such direction and, (c) the
Trustee may take any other action it deems proper which is not inconsistent
with such direction. The right of a Holder of any Debt Security of such series
to institute a proceeding with respect to the Indenture is subject to certain
conditions precedent, but each Holder has an absolute right to receive payment
of principal and premium and interest, if any, when due and to institute suit
for the enforcement of any such payment. The Indenture provides that the
Trustee, within 90 days after the occurrence of any default thereunder with
respect to the Debt Securities of a series, is required to give the Holders of
the Debt Securities of such series notice of any default known to it, unless
cured or waived; provided, however, that, except in the case of a default in
the payment of principal of or premium or interest, if any, on any Debt
Securities of such series, the Trustee may withhold such notice if the Trustee
determines that it is in the interest of such Holders to do so; and, provided,
further, that in the case of an Event of Default of the character specified
above in clause (c) under "Events of Default," no such notice shall be given
to such Holders until at least 75 days after the occurrence thereof.
 
  The Corporation is required to furnish to the Trustee annually a statement
as to the performance by the Corporation of certain of its obligations under
the Indenture and as to any default in such performance. The Corporation is
also required to notify the Trustee of any Event of Default within 10 days
after certain of its officers obtain actual knowledge thereof.
 
                                       8

 
MODIFICATION, WAIVER AND AMENDMENT
 
  Certain modifications and amendments of the Indenture may be made by the
Corporation and the Trustee without the consent of the Holders, including
those which: (a) evidence the assumption by any successor to the Corporation
of the Corporation's obligations under the Indenture or with respect to the
Debt Securities; (b) add to the covenants of or surrender any rights of the
Corporation under the Indenture; (c) add any Events of Default, in addition to
those specified in the Indenture, with respect to all or any series of
Outstanding Debt Securities; (d) change or eliminate any provision of the
Indenture or add any new provision to the Indenture; provided, however, that
if such change, elimination or addition will materially and adversely affect
the interests of Holders of Debt Securities of any series, such change,
elimination or addition will become effective with respect to such series only
when there is no Debt Security of such series remaining outstanding under the
Indenture; (e) provide collateral security for the Debt Securities; (f)
establish the form or terms of Debt Securities of any series; (g) evidence the
appointment of a successor Trustee with respect to the Debt Securities of one
or more series and to add to or change any of the provisions of the Indenture
as shall be necessary to provide for or facilitate the administration of the
trusts under the Indenture by more than one trustee; (h) provide for the
procedures required to permit the utilization of a noncertificated system of
registration for all or any series of Debt Securities; (i) subject to certain
conditions, change the place where Debt Securities may be transferred,
exchanged or paid; or (j) cure any ambiguity or inconsistency or make any
other provisions with respect to matters and questions arising under the
Indenture, provided such provisions shall not adversely affect the interests
of the Holders of Debt Securities of any series in any material respect.
 
  Without limiting the generality of the foregoing, if the Trust Indenture Act
of 1939, as amended (the "Trust Indenture Act"), is amended after the date of
the Indenture to require changes to the Indenture or the incorporation therein
of additional provisions or permit changes to, or the elimination of,
provisions which at the date of the Indenture are required by the Trust
Indenture Act to be contained in the Indenture, the Corporation and the
Trustee may, without the consent of any Holders, enter into one or more
supplemental indentures to effect or reflect any such change, incorporation or
elimination.
 
  Modifications of and amendments to the Indenture may be made by the
Corporation and the Trustee with the consent of the Holders of not less than a
majority in aggregate principal amount of the Outstanding Debt Securities of
each series affected by such modification or amendment voting separately;
provided, however, that no such modification or amendment may, without the
consent of the Holder of each Outstanding Debt Security affected thereby, (a)
change the Stated Maturity of the principal of, or any installment of
principal or interest on, any Debt Security; (b) reduce the principal amount
thereof or the rate of interest thereon or any premium payable upon redemption
thereof; (c) reduce the amount of the principal of Discounted Securities that
would be due and payable upon a declaration of acceleration of the maturity
thereof; (d) change the coin or currency in which any Debt Security or any
premium or the interest thereon is payable; (e) impair the right to institute
suit for the enforcement of any such payment; (f) reduce the percentage in
principal amount of Outstanding Debt Securities of any series, the consent of
whose Holders is required for modification or amendment of the Indenture or
for waiver of compliance with certain provisions of the Indenture or for
waiver of certain defaults; (g) reduce the requirements for quorum or voting;
or (h) modify the provisions of the Indenture relating to the modification of
the Indenture, or the circumstances under which the Holders may waive past
defaults by and certain covenants of the Corporation except to increase the
percentages in principal amount referred to therein.
 
  The Holders of not less than a majority in aggregate principal amount of the
Outstanding Debt Securities of all series with respect to which a certain
covenant or restriction has been specified, may, on behalf of all Holders of
Debt Securities waive compliance by the Corporation with certain covenants of
the Indenture. The Holders of a majority in aggregate principal amount of the
Outstanding Debt Securities of any series may, on behalf of all Holders of
Debt Securities of that series (a) waive any past default under the Indenture
with respect to Debt Securities of that series, except a default (i) in the
payment of principal, premium, if any, or interest on any Debt Security, or
(ii) in respect of a covenant or provision that cannot be modified or amended
without the consent of the Holder of each Outstanding Debt Security affected
thereby, and (b) waive any Event of Default resulting in acceleration of such
Debt Securities in specified circumstances.
 
                                       9

 
CONSOLIDATION, MERGER AND SALE OF ASSETS
 
  The Indenture provides that the Corporation shall not consolidate with or
merge into any other corporation, association, company, joint stock company,
limited liability company or business trust (the "Successor Corporation") or
convey, transfer or lease its properties and assets substantially as an entity
to any Person unless (i) the Successor Corporation into which the Corporation
is merged or into which it is consolidated or the Person to which
substantially all of the Corporation's assets or properties are conveyed,
transferred or leased, is a Person organized under the laws of the United
States, any state thereof or the District of Columbia, and expressly assumes
by means of a supplemental indenture the due and punctual payment of the
principal (and premium, if any) and interest on all the Outstanding Debt
Securities and the performance of every covenant of the Corporation in the
Indenture; (ii) upon the occurrence of such a transaction, treating any
indebtedness for borrowed money which becomes an obligation of the Corporation
as a result of such transaction as having been incurred by the Corporation at
the time of such transaction, no Event of Default, and no event which, after
notice or lapse of time, or both, would become an Event of Default, shall
occur or be continuing; and (iii) the Corporation or the Successor Corporation
or Person delivers to the Trustee an Officers' Certificate and an Opinion of
Counsel stating that the consolidation, merger, conveyance, transfer or lease
and the supplemental indenture complies with the Indenture and all conditions
precedent for such transaction in the Indenture have been complied with.
 
CERTAIN COVENANTS
 
  Maintenance of Property. The Corporation will cause (or, with respect to
property owned in common with others, make reasonable effort to cause) all its
properties used or useful in the conduct of its business to be maintained and
kept in good condition, repair and working order and will cause (or with
respect to property owned in common with others, make reasonable effort to
cause) to be made all necessary repairs, renewals, replacements, betterments
and improvements thereof, all as, in the judgment of the Corporation, may be
necessary so that the business carried on in connection therewith may be
properly conducted; provided, however, that the foregoing shall not prevent
the Corporation from discontinuing, or causing the discontinuance of, the
operation and maintenance of any of its properties if such discontinuance, in
the judgment of the Corporation, (a) is desirable in the conduct of its
business and (b) will not adversely affect the interests of the Holders of
Debt Securities of any series in any material respect.
 
  Corporate Existence. Subject to the rights of the Corporation described
under "Consolidation, Merger and Sale of Assets," the Corporation will do or
cause to be done all things necessary to preserve and keep in full force and
effect its corporate existence and rights (charter and statutory) and
franchises of the Corporation; provided, however, that the Corporation shall
not be required to preserve any such right or franchise if, in the judgment of
the Corporation (a) preservation thereof is no longer desirable in the conduct
of the business of the Corporation and (b) the failure to preserve any such
right or franchise will not adversely affect the interests of the Holders of
Debt Securities of any series in any material respect.
 
  Restriction on Liens. The Corporation will not create, assume, incur or
suffer to exist any mortgage, lien, pledge, charge or encumbrance of any kind
(other than "Excepted Encumbrances") upon property of the Corporation (other
than "Excepted Property") to secure indebtedness without effectively providing
that the Debt Securities shall be secured equally and ratably with the
indebtedness secured by such mortgage, lien, pledge, charge or encumbrance.
Subject to the next succeeding sentence, the foregoing restriction shall not
apply to (1) pledging of any assets of the Corporation as security for payment
of taxes or other similar charges in connection with a good faith contest by
the Corporation as to its liability for such payment; (2) pledging of any
assets of the Corporation to secure a stay or discharge in connection with a
legal proceeding in which the Corporation or a subsidiary is a party or for
the purpose of obtaining insurance coverage or other surety obligations
providing for securing such stay or discharge in the event such stay or
discharge should be required; (3) making deposits or providing security in
connection with tenders, redemptions, contracts or leases to which the
Corporation is a party or deposits for the purpose of terminating obligations
under an indenture; (4) pledging
 
                                      10

 
of assets in connection with the incurrence of indebtedness in aggregate
principal amount not exceeding 5% of the assets of the Corporation as
presented in the financial statements of the Corporation contained in the most
recently filed report on Form 10-K or 10-Q (or successor forms thereto) filed
with the Commission at the time of such pledge; (5) liens, pledges, security
interests or other encumbrances on property, stock or indebtedness of any
corporation existing at the time such corporation becomes a subsidiary of or
is merged into the Corporation, or existing at the time of acquisition of such
property or stock by the Corporation; (6) incurring liens, licenses, pledges,
security interests or other encumbrances to secure payment of all or a part of
the price of acquisition, construction or improvement of property or stock
acquired by the Corporation or to secure any indebtedness incurred by the
Corporation prior to, at the time of, or within 180 days after the later of
the acquisition or completion of construction where the secured debt is
incurred for the purpose of financing all or any part of the purchase price of
such property or construction or improvements thereon; (7) liens, pledges,
security interests or other encumbrances on property of the Corporation
created in favor of a government or any political subdivision or
instrumentality thereof, to secure partial progress, installment, advance or
other payments pursuant to any contract or statute or to secure any
indebtedness or other obligation incurred for the purpose of financing all or
any part of the purchase price or the cost of construction of property subject
to the encumbrance; or (8) any extension, renewal or replacement of any lien
or encumbrance referred to above, provided that the principal amount of the
indebtedness secured thereby is not increased and the lien or security
interest securing the indebtedness is not extended to cover additional
property. Notwithstanding the foregoing, in no event shall the Corporation
create, assume, incur or suffer to exist pursuant to the foregoing clauses (1)
and (3) through (8) any mortgage, lien, pledge, charge or encumbrance on the
capital stock of either of Alagasco or Taurus directly or indirectly owned by
the Corporation. The term "Excepted Encumbrances" means liens for taxes,
assessments or governmental charges not delinquent; liens securing
indebtedness existing in or relating to real estate acquired for right-of-way
purposes; easements or reservations in property of the Company by statute or
ordinance; liens and charges incidental to current construction activities;
obligations or duties created or imposed by municipalities or other public
authority affecting property of the Company; rights reserved to or vested in
any municipality or public authority to control or regulate the Company or use
of its property; irregularities or deficiencies of title with respect to
rights-of-way; and leases made or existing in the ordinary course of business
of the Company. The term "Excepted Property" generally means certain property
or equipment of the Corporation used in the ordinary course of business,
including current assets, vehicles, certain inventories and equipment, as more
particularly defined in the Indenture, and excludes capital stock issued by
Alagasco and Taurus.
 
  Restriction on Sale-Leaseback Transactions. The Corporation will not enter
into any arrangement providing for the lease to the Corporation of any
property of the Corporation (except for temporary leases for a term, including
any renewal thereof, of not more than three years), which property has been or
is to be sold or transferred by the Corporation to the lessor unless the
proceeds of such sale are at least equal to the fair value of such property
and either: (i) the Corporation would be entitled, under the sub-caption
"Restriction on Liens," to create, assume, incur or suffer to exist a
mortgage, lien, pledge, charge or encumbrance to secure indebtedness on the
property to be leased without equally and ratably securing the Offered
Securities; or (ii) the Corporation shall, or covenants that it will, within
120 days of the effective date of any such arrangement (or in the case of
clause (a) below, within six months thereafter pursuant to a commitment
entered into within such 120 day period), apply an amount not less than the
fair value of such property to any one or more of (a) the optional redemption
of, or the purchase and retirement of, the Debt Securities, or (b) the payment
or other retirement of Funded Debt (as defined therein) incurred or assumed by
the Corporation which ranks pari passu with the Debt Securities (other than
Funded Debt owned by the Corporation), or (c) the purchase at not more than
the fair value of property by the Corporation (other than property of the
Corporation involved in such sale).
 
SATISFACTION AND DISCHARGE; DEFEASANCE
 
  The Indenture, with respect to any and all series of Debt Securities (except
for certain specified surviving obligations) will be discharged and canceled
upon the satisfaction of certain conditions, including: (a) the payment in
full of the principal of (and premium, if any) and interest on all series of
the Debt Securities or the
 
                                      11

 
deemed payment in full of such Debt Securities, as described below; (b) the
payment by the Corporation of all other sums required under the Indenture; and
(c) the delivery of a certificate by the Corporation to the Trustee stating
that all conditions precedent relating to the satisfaction and discharge of
the Indenture have been complied with.
 
  In addition, the Corporation may at any time (i) terminate certain of its
obligations under the Indenture with respect to Debt Securities of any series
("legal defeasance") or (ii) terminate its obligations under certain covenants
set forth in the Indenture with respect to Debt Securities of any series,
including the provisions described above under "Certain Covenants--Restriction
on Liens," "--Restriction on Sale-Leaseback Transactions" and "Consolidation,
Merger and Sale of Assets" (after which any omission to comply with such
obligations shall not constitute a Default with respect to such Debt
Securities) ("covenant defeasance"). To exercise either legal defeasance or
covenant defeasance, the Corporation must irrevocably deposit in trust with
the Trustee, for the benefit of the Holders, cash or Eligible Obligations, or
a combination thereof, in such amounts as will be sufficient to pay the
principal of and premium and interest, if any, due and to become due on the
Debt Securities of such series on or prior to their redemption or maturity
date in accordance with the terms of the Indenture and such Debt Securities;
provided either (i) that such money or the proceeds of such Eligible
Obligations shall have been on deposit with the Trustee for a period of at
least 90 days, or (ii) that the Trustee shall have received an Opinion of
Counsel to the effect that payments to Holders with such moneys as proceeds
are not recoverable as a preference under any applicable United States federal
or state law relating to bankruptcy, insolvency, receivership, winding-up,
liquidation, reorganization or relief of debtors. The Corporation must also
comply with certain other conditions, including the delivery of an opinion of
counsel to the effect that the holders of such Debt Securities will not
realize income, gain or loss for Federal income tax purposes as a result of
such defeasance but will realize income, gain or loss on the Debt Securities,
including payments of interest thereon, in the same manner and at the same
times as would have been the case if such defeasance had not occurred. In the
case of legal defeasance, the opinion of counsel must be accompanied by a
ruling of the Internal Revenue Service issued to the Corporation, or based on
a change in law or regulation occurring after the date of the Indenture.
 
  Eligible Obligations include: (a) with respect to Debt Securities
denominated in United States Dollars, Government Obligations (which include
direct obligations of, or obligations unconditionally guaranteed by, the
United States of America entitled to the benefit of the full faith and credit
thereof and certificates, depository receipts or other instruments which
evidence a direct ownership interest in such obligations or in any specific
interest or principal payments due in respect thereof); and (b) with respect
to Debt Securities denominated in a currency other than United States Dollars
or in a composite currency, such other obligations or instruments as shall be
specified with respect to such Debt Securities, as contemplated by the
Indenture.
 
GOVERNING LAW
 
  The Debt Securities and the Indenture will be governed by, and construed in
accordance with, the laws of the State of New York.
 
U.S. FEDERAL TAXATION
 
  The Prospectus Supplement will contain a brief summary of the relevant
United States federal income tax laws applicable to the Offered Debt
Securities.
 
                                      12

 
                         DESCRIPTION OF CAPITAL STOCK
 
  The Corporation's authorized capital stock consists of 30,000,000 shares of
Common Stock, par value $.01 per share (hereinafter and hereinbefore referred
to as the "Common Stock"), and 5,000,000 shares of Preferred Stock, par value
$.01 per share ("Preferred Stock"), each of which is described below. The
Corporation is requesting that its shareholders approve an increase in the
number of authorized shares of Common Stock from 30,000,000 to 75,000,000 at
the annual meeting of its shareholders in January 1998. On December 10, 1997,
14,476,686 shares of Common Stock were issued and outstanding, excluding
shares held in treasury, and no shares of Preferred Stock were issued or
outstanding. The summary description of the capital stock of the Corporation
contained herein is necessarily general and reference should be made in each
case to the Corporation's Restated Certificate of Incorporation, Certificate
of Adoption of Resolutions Designating Series A Junior Participating Preferred
Stock, Bylaws and Rights Agreement which are exhibits to the Registration
Statement of which this Prospectus is a part.
 
COMMON STOCK
 
  General. Subject to any prior rights of the Preferred Stock then
outstanding, holders of Common Stock are entitled to receive dividends as and
when they are declared by the Board of Directors out of funds legally
available therefor. Subject to the rights, if any, of the Preferred Stock, all
voting rights are vested in the holders of shares of Common Stock, each share
being entitled to one vote. The holders of Common Stock are not entitled to
cumulative voting rights in the election of directors, which means that the
holders of more than 50% of the shares of Common Stock voting for election of
directors can elect 100% of the directors if they choose to do so and, in such
event, the holders of the remaining less than 50% of the shares voting for the
election of directors are not able to elect any person or persons to the Board
of Directors. Subject to any prior rights of the Preferred Stock, in the event
of liquidation, the holders of Common Stock are entitled to receive pro rata
any assets distributable to shareholders in respect of shares held by them.
Holders of Common Stock do not have any right to subscribe to any additional
securities which may be issued by the Company. The outstanding shares of
Common Stock are fully paid and nonassessable.
 
  Special Vote Requirements for Certain Transactions. The Restated Certificate
of Incorporation of the Corporation provides that certain specified
transactions or a series of such transactions with an "Interested Stockholder"
(generally defined as a holder of 10% or more of the voting power of the
outstanding voting stock of the Corporation or an affiliate of such a holder)
require approval by the vote of the holders of at least 80% of the then
outstanding shares of voting stock of the Corporation, except in cases in
which either certain price criteria and procedural requirements are satisfied
or the transaction is approved by a majority of the members of the Board of
Directors who are unaffiliated with, and not a nominee of, the Interested
Stockholder and who were directors before the Interested Stockholder became an
Interested Stockholder (or successors to such directors who are neither
affiliated with, nor the nominee of, the Interested Stockholder and who were
recommended to succeed their predecessors by a majority of the directors
meeting such criteria). The specified transactions include (i) a merger or
consolidation of the Corporation or any of its subsidiaries with or into an
Interested Stockholder or any other corporation which is, or after such merger
or consolidation would be, an Affiliate (as defined) of an Interested
Stockholder; (ii) the sale, lease, exchange, mortgage, pledge, transfer or
other disposition of assets of the Corporation or any of its subsidiaries
having a value of $1,000,000 or more to or with an Interested Stockholder or
any Affiliate of an Interested Stockholder; (iii) the issuance or transfer of
stock or other securities of the Corporation or of any of its subsidiaries to
an Interested Stockholder or any Affiliate of any Interested Stockholder in
exchange for cash, securities or other property having a value of $1,000,000
or more; (iv) the adoption of any plan or proposal for the liquidation or
dissolution of the Corporation proposed by or on behalf of an Interested
Stockholder or any Affiliate of any Interested Stockholder; or (v) any
reclassification of securities, recapitalization, merger or consolidation of
the Corporation with a subsidiary or any similar transaction which has the
effect, directly or indirectly, of increasing an Interested Stockholder's or
any Affiliate of an Interested Stockholder's proportionate share of the
outstanding equity securities (or securities convertible thereinto) of the
Corporation or any of its subsidiaries. At present, the Corporation is not
aware of the existence of any shareholder who would be an Interested
Stockholder.
 
                                      13

 
  Provisions with respect to Board of Directors. The Restated Certificate of
Incorporation of the Corporation provides that the members of the Board of
Directors are divided into three classes as nearly equal as possible. Each
class is elected for a three-year term. At each annual meeting of
shareholders, one-third of the members of the Board of Directors are elected
for a three-year term, and the other directors remain in office until their
three-year terms expire. Thus, control of the Board of Directors cannot be
changed in one year; rather, at least two annual meetings must be held before
a majority of the members of the Board of Directors can be changed.
 
  Vacancies on the Board of Directors other than those caused by an increase
in the number of directors may be filled by a majority of the remaining
directors though less than a quorum. A director elected to fill such a vacancy
is elected to serve until the next annual meeting of shareholders. Any
directorship to be filled as a result of an increase in the number of
directors may be filled only by election at an annual meeting or at a special
meeting of shareholders called for such purpose unless Alabama law at such
time permits such vacancy to be filled by a majority of the remaining
directors.
 
  The Alabama Business Corporation Act provides (unless otherwise provided in
a corporation's charter) that a director, or the entire Board of Directors,
may be removed by the shareholders at a meeting of shareholders expressly
called for that purpose with or without cause by vote of the holders of a
majority of the shares of the Corporation then entitled to vote on election of
directors. The Restated Certificate of Incorporation and Bylaws of the
Corporation, however, provide that the affirmative vote of the holders of at
least 80% of the voting power of the outstanding capital stock entitled to
vote for the elections of directors is required to remove a director or the
entire Board of Directors from office.
 
  Special Vote Requirements for Certain Amendments to Restated Certificate of
Incorporation. Certain portions of the Restated Certificate of Incorporation
of the Corporation described in certain of the preceding paragraphs, including
those related to business combinations and the classified Board of Directors,
may be amended only by the affirmative vote of the holders of 80% of the
voting power of the outstanding voting stock of the Corporation.
 
  Possible Effects of Special Provisions. Certain of the provisions contained
in the Restated Certificate of Incorporation and Bylaws of the Corporation
described above have the effect of making it more difficult to change the
Board of Directors and may make the Board of Directors less responsive to
shareholder control. Certain of these provisions also may tend to discourage
attempts by third parties to acquire the Corporation because of the additional
time and expense involved and a greater possibility of failure, and, as a
result, may decrease the likelihood of an acquisition of the Corporation by a
potential purchaser or adversely affect the price that a potential purchaser
would be willing to pay for the capital stock of the Corporation.
 
  Preferred Stock Purchase Rights. In order to protect the Corporation's
shareholders from coercive or unfair takeover tactics, the Corporation's Board
of Directors on July 27, 1988 adopted a Shareholder Rights Plan (the
"Shareholder Rights Plan"). Pursuant to the Shareholder Rights Plan, each
share of the Corporation's Common Stock outstanding has associated with it
two-thirds of one right (a "Right") to purchase, until July 27, 1998 (or, if
earlier, the redemption of the Rights), a unit consisting of 1/100th of one
share of Series A Junior Participating Preferred Stock (the "Unit") at an
exercise price of $80 per Unit, subject to certain antidilution and other
adjustments as provided in the Shareholder Rights Plan. The Shareholder Rights
Plan also approved the further issuance of Rights for all shares of Common
Stock that are subsequently issued unless otherwise specified by the Board.
Accordingly and subject to adjustment as provided above, two-thirds of a Right
will be issued for each share of Common Stock offered hereby. Until certain
specified conditions exist, the Rights will be represented by the certificates
for the Common Stock and will not be exercisable or transferable apart from
the certificates for the Common Stock.
 
  The Rights have certain anti-takeover effects. The Rights will cause
substantial dilution to a person or group that attempts to acquire the
Corporation without conditioning the offer on a substantial number of Rights
being acquired. The Rights should not interfere with any merger or other
business combination approved by the Board of Directors of the Corporation
since, among other things, the Board of Directors may, at its option, at any
time
 
                                      14

 
until 10 days (subject to extension) following the date on which a person or
group acquires 20% or more of the outstanding Common Stock, except under
certain circumstances, redeem all but not less than all the then outstanding
Rights at $.02 per Right.
 
  A Rights Agreement dated as of July 27, 1988, between the Corporation and
AmSouth Bank, N.A., as amended, specifies the terms of the Rights and the
foregoing description of the Rights is qualified in its entirety by reference
to such Rights Agreement, which is an exhibit to the Corporation's
Registration Statement on Form 8-A, as amended, File No. 1-7810, dated August
8, 1988, and which is incorporated by reference herein. See "Incorporation of
Certain Documents by Reference".
 
  Limitations on Dividend Payments. The Corporation is subject to several
indentures and other debt instruments which restrict the Corporation's ability
to pay dividends. Under the most restrictive indenture or other debt
instrument, the Corporation is required to maintain a consolidated tangible
net worth of not less than $80,000,000. At September 30, 1997, the Corporation
had a consolidated tangible net worth of approximately $300,900,000 and
therefore, under the indenture restriction, the Corporation could make
dividend payments in respect of its Common Stock of $220,900,000.
 
  Transfer Agent and Registrar. The transfer agent and registrar for the
Common Stock is Harris Trust and Savings Bank, 311 West Monroe Street, 11th
Floor, Chicago, Illinois 60606 . The Company's Common Stock is listed on the
New York Stock Exchange.
 
PREFERRED STOCK
 
  General. Under the Corporation's Restated Certificate of Incorporation, the
Board of Directors is authorized, without further shareholder action, to
provide for the issuance of up to 5,000,000 shares of Preferred Stock, in one
or more series, with such voting powers, or without voting powers, and with
such designations and relative rights and preferences as shall be set forth in
resolutions providing for the issue thereof adopted by the Board of Directors.
It is not possible to state the actual effect of the authorization and
issuance of Preferred Stock upon the rights of holders of the Common Stock
unless and until the Board of Directors determines the attributes of the
Preferred Stock and the specific rights of its holders. Such effects may
include, however, (i) restrictions on dividends on Common Stock if dividends
on Preferred Stock have not been paid; (ii) dilution of the voting power of
Common Stock to the extent that Preferred Stock has voting rights, or to the
extent that any Preferred Stock series is convertible into Common Stock; (iii)
dilution of the equity interest of Common Stock unless Preferred Stock is
redeemed by the Corporation; and (iv) limitation on the right of holders of
Common Stock to share in the Corporation's assets upon liquidation until
satisfaction of any liquidation preference granted to Preferred Stock.
Although the ability of the Corporation to issue Preferred Stock provides
flexibility in connection with possible acquisitions and other corporate
purposes, its issuance could be used to impede an attempt by a third party to
acquire a majority of the outstanding voting stock of the Corporation.
 
  Series A Junior Participating Preferred Stock. In connection with the
adoption of the Shareholder Rights Plan described above, on July 27, 1988, the
Corporation's Board of Directors designated 150,000 shares of the
Corporation's authorized but unissued Preferred Stock as "Series A Junior
Participating Preferred Stock" (the "Series A Preferred Stock"). The terms of
the Series A Preferred Stock are such that one share of Series A Preferred
Stock will be approximately equivalent to 100 shares of Common Stock. Each
1/100th of one share of Series A Preferred Stock has the same dividend and
voting right as one full share of Common Stock, except that, if dividend
payments on the Series A Preferred Stock are in arrears for six consecutive
quarters, the Corporation's ability to pay dividends on its Common Stock is
restricted, and holders of the Series A Preferred Stock will have enhanced
voting rights. In addition each 1/100th of one share of Series A Preferred
Stock has a minimum quarterly dividend of $.05 per 1/100th of one share, a
liquidation preference and certain other rights preferential to Common Stock.
Pursuant to the Shareholder Rights Plan, Rights have been issued to the
Corporation's shareholders, but such Rights have not yet become exercisable
and no shares of Series A Preferred Stock have been issued.
 
                                      15

 
                             PLAN OF DISTRIBUTION
 
  The Corporation may sell the Offered Securities being offered hereby to
underwriters or through agents or directly to purchasers. The applicable
Prospectus Supplement will set forth the terms of the offering of the Offered
Securities to which such Prospectus Supplement relates, including the name or
names of any underwriters or agents with whom the Corporation has entered into
arrangements with respect to the sale of such Offered Securities, the public
offering or purchase price of such Offered Securities and the net proceeds to
the Corporation from such sale, any underwriting discounts and other items
constituting underwriters' compensation, any discounts and commissions allowed
or paid to dealers, if any, any commissions allowed or paid to agents, and the
securities exchanges, if any, on which the Offered Securities will be listed.
 
  The Offered Securities may be purchased to be re-offered to the public
through underwriting syndicates led by one or more managing underwriters, or
through one or more underwriters. The underwriter or underwriters with respect
to an underwritten offering of the Offered Securities will be named in any
applicable Prospectus Supplement relating to such offering and, if an
underwriting syndicate is used, the managing underwriter or underwriters will
be set forth on the cover page of any applicable Prospectus Supplement. Unless
otherwise set forth in any applicable Prospectus Supplement, the obligations
of the underwriters to purchase the Offered Securities will be subject to
certain conditions precedent, and each of the underwriters with respect to a
sale of Offered Securities will be obligated to purchase all of its allocated
Offered Securities if any are purchased. Any initial public offering price and
any discount or concessions allowed or reallowed or paid to dealers may be
changed from time to time.
 
  Offered Securities may be offered and sold by the Corporation, directly or
through agents designated by the Corporation from time to time, which agents
may be affiliates of the Corporation. Any agent involved in the offer and sale
of the Offered Securities in respect of which this Prospectus is being
delivered will be named, and any commissions payable by the Corporation to
such agent will be set forth, in any applicable Prospectus Supplement. Unless
otherwise indicated in any applicable Prospectus Supplement, any such agent
will be acting on a reasonable efforts basis for the period of its
appointment.
 
  The Debt Securities will be new issues of securities with no established
trading market. Any underwriters to whom such Debt Securities are sold by the
Corporation for public offering and sale may make a market in such Debt
Securities, but such underwriters will not be obligated to do so and may
discontinue any market making at any time without notice. No assurance can be
given as to the liquidity of, or the the trading market for, any Offered
Securities.
 
  Any underwriter or agent participating in the distribution of the Offered
Securities may be deemed to be an underwriter, as that term is defined in the
Securities Act, of the Offered Securities so offered and sold, and any
discounts or commissions received by them from the Corporation and any profit
realized by them on the sale or resale of the Offered Securities may be deemed
to be underwriting discounts and commissions under the Securities Act.
 
  Underwriters, agents and their controlling persons may be entitled, under
agreements entered into with the Corporation, to indemnification by the
Corporation against certain civil liabilities, including liabilities under the
Securities Act or to contribution with respect to payments which the
underwriters or agents may be required to make in respect thereof.
 
                                LEGAL OPINIONS
 
  The legality of the Offered Securities being offered hereby will be passed
upon for the Corporation by Bradley Arant Rose & White LLP, Birmingham,
Alabama, and certain legal matters will be passed upon for any underwriters,
dealers or agents by Winthrop, Stimson, Putnam & Roberts, New York, New York.
As of December 23, 1997, the partners and associates of Bradley Arant Rose &
White LLP beneficially owned approximately 5,000 shares of Common Stock of the
Corporation.
 
                                      16

 
                                    EXPERTS
 
  The consolidated balance sheets of Energen Corporation and its subsidiaries
as of September 30, 1997 and 1996 and the consolidated statements of income,
shareholders' equity, and cash flows for each of the three years in the period
ending September 30, 1997 and the related financial statement schedule, which
are incorporated by reference or included in the Corporation's Annual Report
on Form 10-K for the year ended September 30, 1997 and which are incorporated
by reference in the Prospectus, have been incorporated herein in reliance on
the report of Coopers & Lybrand L.L.P., independent accountants, given on the
authority of that firm as experts in auditing and accounting.
 
                                      17

 
                                    PART II
 
                    INFORMATION NOT REQUIRED IN PROSPECTUS
 
ITEM 14. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION.
 
  The Registrant estimates that the expenses, other than underwriting
commissions and discounts, to be incurred and borne by it in connection with
the proposed sale of the Common Stock and Debt Securities will be as follows:
 

                                                               
    Registration fee (not including registration fees previously
    paid)........................................................ $108,704.00
   *Listing fees.................................................   10,000.00
   *Rating Agency fees...........................................   60,000.00
   *Blue Sky expenses............................................    7,500.00
   *Transfer Agent's fees........................................    1,000.00
   *Fees of Trustee, including counsel and authentication fee....    7,500.00
   *Printing expenses............................................   20,000.00
   *Legal fees and expenses......................................  145,000.00
   *Accounting fees..............................................    8,000.00
   *Miscellaneous expenses.......................................   30,000.00
                                                                  -----------
     *Total expenses............................................. $397,704.00
                                                                  ===========

- --------
* Estimated
 
ITEM 15. INDEMNIFICATION OF DIRECTORS AND OFFICERS.
 
  (a) Article XI of the Registrant's Restated Certificate of Incorporation
provides as follows:
 
  XI. Limitation of Liability:
 
    11.01 A director of the Corporation shall not be liable to the
  Corporation or its shareholders for money damages for any action taken, or
  failure to take action, as a director, except for (i) the amount of a
  financial benefit received by such director to which such director is not
  entitled; (ii) an intentional infliction of harm by such director on the
  Corporation or its shareholders; (iii) a violation of Section 10-2B-8.33 of
  the Code of Alabama of 1975 or any successor provision to such section;
  (iv) an intentional violation by such director of criminal law; or (v) a
  breach of such director's duty of loyalty to the Corporation or its
  shareholders. If the Alabama Business Corporation Act, or any successor
  statute thereto, is hereafter amended to authorize the further elimination
  or limitation of the liability of a director of a corporation, then the
  liability of a director of the Corporation, in addition to the limitations
  on liability provided herein, shall be limited to the fullest extent
  permitted by the Alabama Business Corporation Act, as amended, or any
  successor statute thereto. The limitation on liability of directors of the
  Corporation contained herein shall apply to liabilities arising out of acts
  or omissions occurring subsequent to the adoption of this Article XI and,
  except to the extent prohibited by law, to liabilities arising out of acts
  or omissions occurring prior to the adoption of this Article XI. Any repeal
  or modification of this Article XI by the shareholders of the Corporation
  shall be prospective only and shall not adversely affect any limitation on
  the liability of a director of the Corporation existing at the time of such
  repeal or modification.
 
  (b) Section 2.06 of the Registrant's Bylaws provides as follows:
 
  2.06 Indemnification of Directors and Officers; Liability Insurance--
 
    (a) The Corporation does hereby indemnify any officer or director of the
  Corporation who was, or is, a party, or is threatened to be made a party,
  to any threatened, pending, or completed claim, action, or proceeding,
  whether civil, criminal, administrative, or investigative, including
  appeals, other than an action by or in the right of the Corporation, by
  reason of the fact that he is or was a director, an officer, an employee,
  or an agent of the Corporation or is, or was, serving at the request of the
  Corporation as a director, officer partner, employee, or agent of another
  corporation, partnership, joint venture, trust, or other
 
                                     II-1

 
  enterprise against expenses, including attorneys' fee, judgments, fines,
  and amounts paid in settlement actually and reasonably incurred by him in
  connection with such action or proceeding if he acted in good faith and in
  a manner he reasonably believed to be in or not opposed to the best
  interests of the Corporation and, with respect to any criminal action or
  proceeding, had no reasonably cause to believe his conduct was unlawful.
  The termination of any action or proceeding by judgment, order, settlement,
  conviction, or upon a plea of nolo contendere, or its equivalent, shall
  not, of itself, create a presumption that the person did not act in good
  faith and in a manner which he reasonably believed to be in or not opposed
  to the best interests of the Corporation and, with respect to any criminal
  action or proceeding, had reasonable cause to believe that his conduct was
  unlawful.
 
    (b) The Corporation does hereby indemnify any officer or director of the
  Corporation who was, or is, a party, or is threatened to be made a party,
  to any threatened, pending, or completed claim or action by, or in the
  right of, the Corporation to procure a judgment in its favor by reason of
  the fact that he is or was a director, an officer, an employee, or an agent
  of the Corporation, or is or was serving at the request of the Corporation
  as a director, officer, partner, employee, or agent of another corporation,
  partnership, joint venture, trust, or other enterprise against expenses,
  including attorneys' fees, actually and reasonably incurred by him in
  connection with the defense or settlement of such action if he acted in
  good faith and in a manner he reasonably believed to be in, or not opposed
  to, the best interests of the Corporation, except that no indemnification
  shall be made in respect of any claim, issue, or matter as to which such
  person shall have been adjudged to be liable for negligence or misconduct
  in the performance of his duty to the Corporation unless, and only to the
  extent that the court in which such action was brought shall determine upon
  application that, despite the adjudication of liability but in view of all
  circumstances of the case, such person is fairly and reasonably entitled to
  indemnity for such expenses which such court shall deem proper.
 
    (c) To the extent that a director or an officer of the Corporation has
  been successful on the merits or otherwise in defense of any action or
  proceeding referred to in subsections (a) and (b) of this section or in
  defense of any claim, issue, or matter therein, he shall be indemnified
  against expenses, including attorneys' fees, actually and reasonably
  incurred by him in connection therewith, notwithstanding that he has not
  been successful on any other claim, issue, or matter in any such action or
  proceeding.
 
    (d) Any indemnification under subsections (a) and (b) of this section,
  unless ordered by a court, shall be made by the Corporation only as
  authorized in the specific case upon a determination that indemnification
  of the director or officer is proper in the circumstances because he has
  met the applicable standard of conduct set forth in subsections (a) and (b)
  of this section. Such determination shall be made:
 
      (i) By the Board of Directors by a majority vote of a quorum
    consisting of directors who were not parties to, or who have been
    wholly successful on the merits or otherwise with respect to, such
    claim, action, or proceeding;
 
      (ii) If such a quorum is not obtainable, or even if obtainable a
    quorum of disinterested directors so directs, by independent legal
    counsel in a written opinion; or
 
      (iii) By the stockholders.
 
    (e) Expenses, including attorneys' fees, incurred in defending a civil or
  criminal claim, action, or proceeding may be paid by the Corporation in
  advance of the final disposition of such claim, action, or proceeding as
  authorized in the manner provided in subsection (d) of this section upon
  receipt of an undertaking by or on behalf of the director or officer to
  repay such amount if, and to the extent that, it shall ultimately be
  determined that he is not entitled to be indemnified by the Corporation as
  authorized in this section.
 
    (f) The indemnification authorized by this section shall not be deemed
  exclusive of, and shall be in addition to, any other rights, whether
  created prior or subsequent to the enactment of this section, to which
  those indemnified may be entitled under any statute, rule of law, provision
  of articles of incorporation, by-law, agreement, or vote of stockholders or
  disinterested directors, or otherwise, both as to action in his official
  capacity and as to action in another capacity while holding such office and
  shall continue as to a person who has ceased to be a director or an
  officer, and shall inure to the benefit of the heirs, executors, and
  administrators of such a person.
 
                                     II-2

 
    (g) The Corporation shall have power to purchase and maintain insurance
  on behalf of any person who is or was a director or an officer of the
  Corporation, or is or was serving at the request of the Corporation as a
  director, officer, partner, employee, or agent of another corporation,
  partnership, joint venture, trust, or other enterprise against any
  liability asserted against him and incurred by him in any such capacity or
  arising out of his status as such, whether or not the Corporation would
  have the power to indemnify him against such liability under the provisions
  of this section."
 
  (c) In addition to the foregoing provisions of the Bylaws of the Registrant,
directors, officers and controlling persons of the Registrant may be
indemnified by the Registrant pursuant to the provisions of Sections 10-2B-
8.50 to 10-2B-8.58 of the Code of Alabama of 1975, as amended, which indemnity
may be broader than that provided by the Registrant's Bylaws.
 
  (d) In addition, the Registrant maintains officers' and directors' liability
insurance.
 
ITEM 16. EXHIBITS
 


 EXHIBIT NO.                             DESCRIPTION
 -----------                             -----------
          
 1(a)        Form of Selling Agency Agreement.
 1(b)        Form of Common Stock Underwriting Agreement.
 *4(a)       Restated Conformed Certificate of Incorporation of the Registrant,
             as amended through February 3, 1995, which was filed as Exhibit
             3(f) to the Registrant's Annual Report on Form 10-K for the year
             ended September 30, 1995 (File No. 1-7810).
 *4(b)       Certificate of Adoption of Resolutions Designating Series A Junior
             Participating Preferred Stock, adopted June 27, 1988, which was
             filed as Exhibit 4(e) to the Registrant's Registration Statement
             on Form S-2 (Registration No. 33-25435).
 *4(c)       Bylaws of the Registrant, which were filed as Exhibit 4(e) to the
             Registrant's Registration Statement on Form S-8 (Registration No.
             33-14855).
 *4(d)       Rights Agreement, dated as of July 27, 1988, between Energen
             Corporation and AmSouth Bank N.A., Rights Agent, which was filed
             as Exhibit I to the Registrant's Registration Statement on Form 8-
             A (File No. 1-7810).
 *4(e)       Amendment of Rights Agreement, dated as of February 28, 1990,
             between Energen Corporation and AmSouth Bank N.A., Rights Agent,
             which was filed as Exhibit 2 to Registrant's Form 8 Amendment No.
             2 to its Registration Statement on Form 8-A (File No. 1-7810).
 *4(f)       Indenture, dated as of January 1, 1992, between the Registrant and
             Boatmen's Trust Company, Trustee, which was filed as Exhibit 4 to
             the Registrant's Registration Statement on Form S-3 (Registration
             No. 33-44936).
 *4(g)       Indenture, dated as of March 1, 1993, between the Registrant and
             Boatman's Trust Company, Trustee, which was filed as Exhibit 4 to
             the Registrant's Registration Statement on Form S-3 (Registration
             No. 33-25435).
 *4(h)       Indenture dated as of November 1, 1993, between Alabama Gas
             Corporation and NationsBank of Georgia, National Association,
             Trustee, which was filed as Exhibit 4(k) to Alabama Gas's
             Registration Statement on Form S-3 (Registration No. 33-70466).
 4(i)        Indenture between Energen Corporation and The Bank of New York, as
             Trustee, dated as of September 1, 1996, with respect to the Debt
             Securities.
 5           Opinion of Bradley Arant Rose & White LLP.
 12          Computation of Ratios of Earnings to Fixed Charges.
 23(a)       Consent of Bradley Arant Rose & White LLP (contained in their
             opinion filed as Exhibit 5 to this Registration Statement).
 23(b)       Consent of Coopers & Lybrand L.L.P.
 24          Power of attorney authorizing execution of registration statement
             on Form S-3 on behalf of certain directors of the Registrant.
 25          Statement of Eligibility and Qualification of the Trustee under
             the Trust Indenture Act of 1939 on Form T-1.

- --------
* Incorporated by reference.
 
                                     II-3

 
ITEM. 17. UNDERTAKINGS.
 
  (a) 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 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 end 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 the undertakings set forth in paragraphs (1)(i)
  and (1)(ii) above do not apply if the registration statement is on Form S-
  3, Form S-8, or Form F-3, and 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 this 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) The undersigned registrant hereby undertakes that, for the 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 (and, where applicable, each filing of any
employee benefit plan's annual report pursuant to section 15(d) of the
Securities Exchange Act of 1934) that is incorporated by reference in this
registration statement shall be deemed to be a new registration statement
relating to the securities offered herein, and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof.
 
  (c) 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 provisions described under Item 15 above, 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 labilities (other than the
payment by the registrant of expenses incurred or paid by a director, officer
or controlling person of such registrant in the successful defense of any
action, suit or proceeding) is asserted against the registrant 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-4

 
  (d) 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 a part of this Registration
Statement in reliance upon rule 430A and contained in a form of prospectus
filed pursuant to Rules 424(b)(1) or (4) or 497(h) under the Securities Act
shall be deemed to be a part of this Registration Statement at the time it was
declared effective, and (2) for the purpose of determining any liability under
the Securities Act of 1933, each post-effective amendment if that contains a
form of prospectus shall be deemed to be a new registration statement relating
to the Securities offered therein, and the offering of such securities at that
time shall be deemed to be the initial bona fide offering thereof.
 
                                     II-5

 
                                  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 BIRMINGHAM, STATE OF ALABAMA, ON DECEMBER 23, 1997.
 
                                          Energen Corporation
 
                                                  /s/ Geoffrey C. Ketcham
                                          By: _________________________________
                                                    GEOFFREY C. KETCHAM
                                               ITS EXECUTIVE VICE PRESIDENT,
                                                       TREASURER AND
                                                  CHIEF FINANCIAL OFFICER
 
  PURSUANT TO THE REQUIREMENTS OF THE SECURITIES ACT OF 1933, THIS
REGISTRATION STATEMENT HAS BEEN SIGNED BELOW BY THE FOLLOWING PERSONS IN THE
CAPACITIES AND ON THE DATES INDICATED.
 
              SIGNATURE                        TITLE                 DATE
 
                  *                    Director                  December 23,
- -------------------------------------                                1997
           STEPHEN D. BAN
 
                  *                    Director                  December 23,
- -------------------------------------                                1997
          JULIAN W. BANTON
 
                  *                    Director                  December 23,
- -------------------------------------                                1997
             R. D. CASH
 
                  *                    Director                  December 23,
- -------------------------------------                                1997
         J. MASON DAVIS, JR.
 
                  *                    Director                  December 23,
- -------------------------------------                                1997
         JAMES S. M. FRENCH
 
       /s/ Geoffrey C. Ketcham         Executive Vice            December 23,
- -------------------------------------   President,                   1997
         GEOFFREY C. KETCHAM            Treasurer and Chief
                                        Financial Officer
                                        (Principal
                                        Accounting Officer)
 
                  *
                                                                 December 23,
- -------------------------------------                                1997
          WALLACE L. LUTHY
 
                  *                    Chairman of the           December 23,
- -------------------------------------   Board and Director           1997
           REX J. LYSINGER
 
                                     II-6

 
              SIGNATURE                         TITLE                DATE
 
                  *                     Director                 December 23,
- -------------------------------------                                1997
           JUDY M. MERRITT
 
                  *                     Director                 December 23,
- -------------------------------------                                1997
         DRAYTON NABERS, JR.
 
                  *                     Director                 December 23,
- -------------------------------------                                1997
          GEORGE S. SHIRLEY
 
                  *                     President, Chief         December 23,
- -------------------------------------    Executive Officer           1997
       WM. MICHAEL WARREN, JR.           and Director
 
       /s/ Geoffrey C. Ketcham
  *By:_______________________________                            December 23,
        GEOFFREY C. KETCHAM,                                         1997
          ATTORNEY-IN-FACT
 
                                      II-7

 
           REGISTRATION STATEMENT ON FORM S-3 OF ENERGEN CORPORATION
 
                               ----------------
 
                               INDEX OF EXHIBITS
 


 EXHIBIT
 NUMBER                                DESCRIPTION
 -------                               -----------
      
   1(a)  Form of Selling Agency Agreement.
   1(b)  Form of Common Stock Underwriting Agreement.
  *4(a)  Restated Conformed Certificate of Incorporation of the Registrant, as
         amended through February 3, 1995, which was filed as Exhibit 3(f) to
         the Registrant's Annual Report on Form 10-K for the year ended
         September 30, 1995 (File No. 1-7810).
  *4(b)  Certificate of Adoption of Resolutions Designating Series A Junior
         Participating Preferred Stock, adopted June 27, 1988, which was filed
         as Exhibit 4(e) to the Registrant's Registration Statement on Form S-2
         (Registration No. 33-25435).
  *4(c)  Bylaws of the Registrant, which were filed as Exhibit 4(e) to the
         Registrant's Registration Statement on Form S-8 (Registration No. 33-
         14855).
  *4(d)  Rights Agreement, dated as of July 27, 1988, between Energen
         Corporation and AmSouth Bank N.A., Rights Agent, which was filed as
         Exhibit I to the Registrant's Registration Statement on Form 8-A (File
         No. 1-7810).
  *4(e)  Amendment of Rights Agreement, dated as of February 28, 1990, between
         Energen Corporation and AmSouth Bank N.A., Rights Agent, which was
         filed as Exhibit 2 to Registrant's Form 8 Amendment No. 2 to its
         Registration Statement on Form 8-A (File No. 1-7810).
  *4(f)  Indenture, dated as of January 1, 1992, between the Registrant and
         Boatmen's Trust Company, Trustee, which was filed as Exhibit 4 to the
         Registrant's Registration Statement on Form S-3 (Registration No. 33-
         44936).
  *4(g)  Indenture, dated as of March 1, 1993, between the Registrant and
         Boatman's Trust Company, Trustee, which was filed as Exhibit 4 to the
         Registrant's Registration Statement on Form S-3 (Registration No. 33-
         25435).
  *4(h)  Indenture dated as of November 1, 1993, between Alabama Gas
         Corporation and NationsBank of Georgia, National Association, Trustee,
         which was filed as Exhibit 4(k) to Alabama Gas's Registration
         Statement on Form S-3 (Registration No. 33-70466).
   4(i)  Indenture between Energen Corporation and The Bank of New York, as
         Trustee, dated as of September 1, 1996, with respect to the Debt
         Securities.
   5     Opinion of Bradley Arant Rose & White LLP.
  12     Computation of Ratios of Earnings to Fixed Charges.
  23(a)  Consent of Bradley Arant Rose & White LLP (contained in their opinion
         filed as Exhibit 5 to this Registration Statement).
  23(b)  Consent of Coopers & Lybrand L.L.P.
  24     Power of attorney authorizing execution of registration statement on
         Form S-3 on behalf of certain directors of the Registrant.
  25     Statement of Eligibility and Qualification of the Trustee under the
         Trust Indenture Act of 1939 on Form T-1.

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* Incorporated by reference.