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                                                                   EXHIBIT 4.2.1



                         SECOND SUPPLEMENTAL INDENTURE
                       TO INDENTURE DATED MARCH 15, 1997
                              (8 1/2% Securities)

                 SECOND SUPPLEMENTAL INDENTURE dated as of April 22, 1998,
among CHESAPEAKE ENERGY CORPORATION, an Oklahoma corporation (the "Company"),
the SUBSIDIARY GUARANTORS listed as signatories hereto, UNITED STATES TRUST
COMPANY OF NEW YORK, a New York corporation, as Trustee to the Indenture (as
such term is defined in Article I below) and CHESAPEAKE ENERGY MARKETING, INC.,
an Oklahoma Corporation ("CEM"), CHESAPEAKE ACQUISITION CORPORATION, an
Oklahoma corporation ("CAC"), CHESAPEAKE MID-CONTINENT CORP., an Oklahoma
corporation ("CMCC"), ANSON GAS MARKETING, an Oklahoma general partnership
("AGM"), MID-CONTINENT GAS PIPELINE COMPANY, an Oklahoma general partnership
("MCGPC"), CHESAPEAKE MERGER CORP., an Oklahoma corporation ("CMC"), CHESAPEAKE
COLUMBIA CORP., an Oklahoma corporation ("CCC"), HUGOTON ENERGY CORPORATION, a
Kansas corporation ("HEC"), HUGOTON EXPLORATION CORPORATION, a Kansas
corporation ("HEX"), HEC TRADING COMPANY, a Texas corporation ("HECTC"),
TIFFANY GATHERING, INC., a Delaware corporation ("TGI") and AMGAS CORPORATION,
a Kansas corporation ("AC").

                 WHEREAS, the Company, the Subsidiary Guarantors and the
Trustee have heretofore entered into the Original Indenture, pursuant to the
provisions of which the Company has heretofore issued $150,000,000 in aggregate
principal amount of the Securities and the First Supplemental Indenture dated
as of December 17, 1997;

                 WHEREAS,  CEM, CAC, CMCC, AGM, MCGPC, CMC, CCC, HEC, HEX,
HECTC, TGI and AC are Subsidiaries of the Company;

                 WHEREAS, the Board of Directors of the Company has adopted
resolutions designating CEM, CAC, CMCC, AGM, MCGPC, CMC, CCC, HEC, HEX, HECTC,
TGI and AC as Restricted Subsidiaries, as that term is defined in the
Indenture;

                 WHEREAS, Section 10.3(b) of the Indenture provides, among
other things, that the Company will cause each Subsidiary that shall become a
Restricted Subsidiary after the Issue Date to execute and deliver a
supplemental indenture pursuant to which such Restricted Subsidiary shall
guarantee the payment of the Securities pursuant to the terms of the Indenture;

                 WHEREAS, Section 10.3(c) of the Indenture provides, among
other things, that a Person may become a Subsidiary Guarantor by executing and
delivering to the Trustee (i) a supplemental indenture which is in form and
substance satisfactory to the Trustee and which subjects such Person to the
provisions (including the representations and warranties) of the Indenture as a
Subsidiary Guarantor and (ii) an Opinion of Counsel and Officer's Certificate
that such supplemental indenture has been duly authorized and executed by such
Person and constitutes the legal, valid, binding and enforceable obligation of
such Person;
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                 WHEREAS, the form and substance of this Second Supplemental
Indenture are satisfactory to the Trustee;

                 WHEREAS, contemporaneously herewith, there are being delivered
to the Trustee executed opinions of counsel and officers' certificate's proper
in form and substance;

                 WHEREAS, Section 9.1 of the Indenture provides, among other
things, that the Trustee, the Subsidiary Guarantors and the Company may amend
or supplement the Indenture without notice to or consent of any Holder to
reflect the addition of any Subsidiary Guarantor, as provided for by the
Indenture; and

                 WHEREAS, the execution and delivery of this Second
Supplemental Indenture have been duly authorized by the Company, the Subsidiary
Guarantors, CEM, CAC, CMCC, AGM, MCGPC, CMC, CCC, HEC, HEX, HECTC, TGI and AC
and all actions necessary to make this Second Supplemental Indenture a valid
and binding instrument according to its terms and the terms of the Original
Indenture have been performed.

                 NOW, THEREFORE, BY THIS Second SUPPLEMENTAL INDENTURE, for and
in consideration of the premises and of the mutual covenants herein contained
and for other valuable considerations, the receipt whereof is hereby
acknowledged, the Company, the Subsidiary Guarantors, CEM, CAC, CMCC, AGM,
MCGPC, CMC, CCC, HEC, HEX, HECTC, TGI and AC covenant and agree with the
Trustee, for the equal benefit of all present and future Holders of the
Securities, as follows:


                                   ARTICLE I

                                  DEFINITIONS

                 SECTION 1.1      The definitions set forth in or incorporated
by reference in Article I of the Indenture shall be applicable to this Second
Supplemental Indenture, as fully and to the same extent as if set forth herein,
except as otherwise expressly provided herein.  As used in this Second
Supplemental Indenture, the following terms shall have the following meanings:

                 "Indenture" means the Original Indenture, as amended by this
Second Supplemental Indenture, relating to the Securities.

                 "Original Indenture" means the Indenture dated as of March 15,
1997, among the Company, the Subsidiary Guarantors listed as signatories
thereto and the Trustee, relating to the Securities, as amended by: (i) that
certain First Supplemental Indenture dated as of December 17, 1997.
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                                   ARTICLE II

                        ADDITION OF SUBSIDIARY GUARANTOR

                 SECTION 2.1      As a Subsidiary Guarantor, each of CEM, CAC,
CMCC, AGM, MCGPC, CMC, CCC, HEC, HEX, HECTC, TGI and AC hereby: (a) jointly and
severally, unconditionally guarantees to each Holder and to the Trustee the due
and punctual payment of the principal of, premium, if any, and interest on the
Securities and all other amounts due and payable under the Indenture and the
Securities by the Company, whether at maturity, by acceleration, redemption,
repurchase or otherwise including, without limitation, interest on the overdue
principal of, premium, if any, and interest on the Securities to the extent
lawful, all in accordance with the terms and subject to the limitations of the
Indenture as if each of CEM, CAC, CMCC, AGM, MCGPC, CMC, CCC, HEC, HEX, HECTC,
TGI and AC had been an original party thereto; and (b) subjects each of CEM,
CAC, CMCC, AGM, MCGPC, CMC, CCC, HEC, HEX, HECTC, TGI and AC to the provisions
(including the representations and warranties) of the Indenture as a Subsidiary
Guarantor.


                                  ARTICLE III

                                 MISCELLANEOUS

                 SECTION 3.1      This Second Supplemental Indenture is a
supplemental indenture pursuant to Section 9.1 of the Indenture.  Upon
execution and delivery of this Second Supplemental Indenture, the terms and
conditions of this Second Supplemental Indenture will be part of the terms and
conditions of the Indenture for any and all purposes, and all the terms and
conditions of both shall be read together as though they constitute one
instrument, except that in case of conflict, the provisions of this Second
Supplemental Indenture will control.

                 SECTION 3.2      Except as they have been modified in this
Second Supplemental Indenture, each and every term and provision of the
Indenture shall remain in full force and effect.

                 SECTION 3.3      This Second Supplemental Indenture may be
executed in any number of counterparts, each of which when so executed and
delivered shall be an original, but such counterparts shall together constitute
but one and the same instrument.

                 SECTION 3.4      This Second Supplemental Indenture shall be
governed by and construed in accordance with the laws of the State of New York
without giving effect to applicable principals of conflicts of law to the
extent that the application of the law of another jurisdiction would be
required thereby.
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                                   SIGNATURES

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

                                       CHESAPEAKE ENERGY CORPORATION, an
                                       Oklahoma corporation

                                       By  /s/ AUBREY K. MCCLENDON
                                          -------------------------------------
                                          Aubrey K. McClendon, Chief
                                          Executive Officer


                                       UNITED STATES TRUST COMPANY OF NEW
                                       YORK, a New York corporation, as Trustee

                                       By /s/ GERARD F. GANEY
                                          -------------------------------------
                                         Name: Gerard F. Ganey
                                               --------------------------------
                                         Title: Senior Vice President
                                                -------------------------------


                                       CHESAPEAKE ENERGY MARKETING, INC., an 
                                       Oklahoma Corporation

                                       By  /s/ AUBREY K. MCCLENDON
                                          -------------------------------------
                                          Aubrey K. McClendon, Chairman


                                       CHESAPEAKE ACQUISITION CORPORATION, an 
                                       Oklahoma corporation

                                       By  /s/ AUBREY K. MCCLENDON
                                          -------------------------------------
                                          Aubrey K. McClendon, President


                                       CHESAPEAKE MID-CONTINENT CORP., an 
                                       Oklahoma corporation

                                       By  /s/ AUBREY K. MCCLENDON
                                          -------------------------------------
                                          Aubrey K. McClendon, President
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                                       ANSON GAS MARKETING, an Oklahoma general
                                       partnership

                                       By Chesapeake Mid-Continent Corp., an 
                                          Oklahoma corporation, General Partner
                                       
                                          By  /s/ AUBREY K. MCCLENDON
                                            ------------------------------------
                                            Aubrey K. McClendon, President


                                       MID-CONTINENT GAS PIPELINE COMPANY, an 
                                       Oklahoma general partnership

                                       By Chesapeake Mid-Continent Corp., an 
                                          Oklahoma corporation, General Partner

                                          By  /s/ AUBREY K. MCCLENDON
                                            ------------------------------------
                                            Aubrey K. McClendon, President


                                       CHESAPEAKE MERGER CORP., an Oklahoma 
                                       corporation

                                       By  /s/ AUBREY K. MCCLENDON
                                          -------------------------------------
                                          Aubrey K. McClendon, President


                                       CHESAPEAKE COLUMBIA CORP., an Oklahoma 
                                       corporation

                                       By  /s/ AUBREY K. MCCLENDON
                                          -------------------------------------
                                          Aubrey K. McClendon, President


                                       HUGOTON ENERGY CORPORATION, a Kansas 
                                       corporation

                                       By  /s/ AUBREY K. MCCLENDON
                                          -------------------------------------
                                          Aubrey K. McClendon, President


                                       HUGOTON EXPLORATION CORPORATION, a 
                                       Kansas corporation

                                       By  /s/ AUBREY K. MCCLENDON
                                          -------------------------------------
                                          Aubrey K. McClendon, President
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                                       HEC TRADING COMPANY, a Texas corporation

                                       By  /s/ AUBREY K. MCCLENDON
                                          -------------------------------------
                                          Aubrey K. McClendon, President


                                       TIFFANY GATHERING, INC., a Delaware 
                                       corporation

                                       By  /s/ AUBREY K. MCCLENDON
                                          -------------------------------------
                                          Aubrey K. McClendon, President


                                       AMGAS CORPORATION, a Kansas corporation

                                       By  /s/ AUBREY K. MCCLENDON
                                          -------------------------------------
                                          Aubrey K. McClendon, President


                                       SUBSIDIARY GUARANTORS

                                       CHESAPEAKE OPERATING, INC., an Oklahoma
                                       corporation

                                       By  /s/ AUBREY K. MCCLENDON
                                          -------------------------------------
                                          Aubrey K. McClendon, Chief Executive 
                                          Officer


                                       CHESAPEAKE EXPLORATION LIMITED 
                                       PARTNERSHIP, an Oklahoma limited 
                                       partnership

                                       By  Chesapeake Operating, Inc., an
                                           Oklahoma corporation, Sole
                                           General Partner

                                           By  /s/ AUBREY K. MCCLENDON
                                             ----------------------------------
                                             Aubrey K. McClendon, Chief 
                                             Executive Officer

                                       CHESAPEAKE ENERGY LOUISIANA CORPORATION,
                                       an Oklahoma corporation

                                       By   /s/ AUBREY K. MCCLENDON
                                           ------------------------------------
                                           Aubrey K. McClendon, Chief Executive
                                           Officer


                                       CHESAPEAKE CANADA CORPORATION, an 
                                       Alberta, Canada corporation 

                                       By  /s/ AUBREY K. MCCLENDON
                                          -------------------------------------
                                          Aubrey K. McClendon, Chief Executive 
                                          Officer


                                       CHESAPEAKE LOUISIANA, L.P., an Oklahoma 
                                       limited partnership

                                       By  Chesapeake Operating, Inc., an
                                           Oklahoma corporation, Sole
                                           General Partner

                                           By  /s/ AUBREY K. MCCLENDON
                                             ----------------------------------
                                             Aubrey K. McClendon, Chief 
                                             Executive Officer