First Supplemental Indenture dated as of July 15, 2005



 Exhibit 4.12.1 

  
 CHESAPEAKE ENERGY CORPORATION 
  
 and 
  
 the Subsidiary Guarantors named herein 
  

  
 6.625% SENIOR NOTES DUE 2016 
  

  
 FIRST SUPPLEMENTAL INDENTURE 
  
 DATED AS OF JULY 15, 2005 
  

  
 THE BANK OF NEW YORK TRUST COMPANY, N.A. 
  
 as Trustee 
  

  










 THIS FIRST SUPPLEMENTAL INDENTURE, dated as of July 15, 2005, is among Chesapeake Energy Corporation, an
Oklahoma corporation (the “Company”), each of the parties identified under the caption “Subsidiary Guarantors” on the signature page hereto (the “Subsidiary Guarantors”) and The Bank of New
York Trust Company, N.A., as Trustee. 
  
 RECITALS

  
 WHEREAS, the Company, the Subsidiary Guarantors a party
thereto and the Trustee entered into an Indenture, dated as of April 19 2005, (the “Indenture”), pursuant to which the Company has originally issued $600,000,000 in principal amount of 6.625% Senior Notes due 2016 (the
“Notes”); and 
  
 WHEREAS, Section 9.01(3) of the
Indenture provides that the Company, the Subsidiary Guarantors and the Trustee may amend or supplement the Indenture without notice to or consent of any Holder to reflect the release of any Subsidiary Guarantor, as provided for in the Indenture; and

  
 WHEREAS, the Company has taken all actions required to effect
the release, pursuant to Sections 10.02 and 10.04 of the Indenture, of Chesapeake PPC Corp., a Texas corporation as Subsidiary Guarantor; and 
  
 WHEREAS, all acts and things prescribed by the Indenture, by law and by the charter and the bylaws (or comparable constituent documents) of the Company,
of the Subsidiary Guarantors and of the Trustee necessary to make this First Supplemental Indenture a valid instrument legally binding on the Company, the Subsidiary Guarantors and the Trustee, in accordance with its terms, have been duly done and
performed; 
  
 NOW, THEREFORE, to comply with the provisions of
the Indenture and in consideration of the above premises, the Company, the Subsidiary Guarantors and the Trustee covenant and agree for the equal and proportionate benefit of the respective Holders of the Notes as follows: 
  
 ARTICLE 1 
  
 Section 1.01. This First Supplemental Indenture is supplemental to the Indenture and does and shall be deemed to form
a part of, and shall be construed in connection with and as part of, the Indenture for any and all purposes. 
  
 Section 1.02. This First Supplemental Indenture shall become effective immediately upon its execution and delivery by each of the Company, the
Subsidiary Guarantors and the Trustee. 
  

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 ARTICLE 2 
  

Section 2.01. As a result of the merger of Chesapeake PPC Corp., with and into Chesapeake Exploration Limited Partnership, an Oklahoma limited
partnership (“CELP”), which constitutes a merger with a Subsidiary Guarantor under Section 10.02(a) of the Indenture, Chesapeake PPC Corp., shall for all purposes be released as a Subsidiary Guarantor from all of its Guarantees and related
obligations in the Indenture, pursuant to Section 10.04 of the Indenture. The notation on the Securities relating to the Guarantee shall be deemed to exclude the name of Chesapeake PPC Corp. and the signature of an Officer of Chesapeake PPC Corp.

  
 Section 2.02. As the surviving entity in its merger
with Chesapeake PPC Corp. and a Subsidiary Guarantor, CELP hereby agrees to assume all of the obligations of Chesapeake PPC Corp. 
  
 ARTICLE 3 
  
 Section 3.01. Except as specifically modified herein, the Indenture and the Notes are in all respects ratified and confirmed (mutatis
mutandis) and shall remain in full force and effect in accordance with their terms with all capitalized terms used herein without definition having the same respective meanings ascribed to them as in the Indenture. 
  
 Section 3.02. Except as otherwise expressly provided herein, no
duties, responsibilities or liabilities are assumed, or shall be construed to be assumed, by the Trustee by reason of this First Supplemental Indenture. This First Supplemental Indenture is executed and accepted by the Trustee subject to all the
terms and conditions set forth in the Indenture with the same force and effect as if those terms and conditions were repeated at length herein and made applicable to the Trustee with respect hereto. 
  
 Section 3.03. THE LAW OF THE STATE OF NEW YORK SHALL GOVERN AND BE
USED TO CONSTRUE AND ENFORCE THIS FIRST SUPPLEMENTAL INDENTURE. 
  
 Section 3.04. The parties may sign any number of copies of this First Supplemental Indenture. Each signed copy shall be an original, but all of such executed copies together shall represent the same agreement. 
  
 [NEXT PAGE IS SIGNATURE PAGE] 
  

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

	
	
	 /s/ Aubrey K. McClendon

	 Aubrey K. McClendon

	  
 Chief Executive Officer of the Company
and of the
Subsidiaries listed below:
  
 Corporate Subsidiaries:
  
 CHESAPEAKE EAGLE CANADA CORP.
 CHESAPEAKE ENERGY LOUISIANA CORPORATION
 CHESAPEAKE PRH CORP.
 CHESAPEAKE SOUTH TEXAS CORP.
 NOMAC DRILLING CORPORATION
 OXLEY PETROLEUM CO.
  
 CHESAPEAKE OPERATING, INC.,
 On
behalf of itself and, as general partner, the
following limited partnerships:
  
 CHESAPEAKE EXPLORATION LIMITED PARTNERSHIP
 CHESAPEAKE LOUISIANA, L.P.
 CHESPEAKE NFW, L.P.
 CHESAPEAKE PERMIAN, L.P.
 CHESAPEAKE SIGMA, L.P.
 CHESAPEAKE-STAGHORN ACQUISITION, L.P.
 CHESAPEAKE ZAPATA, L.P.
  
 CHESAPEAKE ENERGY MARKETING, INC.,
 On behalf of itself and, as general partner, the
following limited partnerships:
  
 MIDCON COMPRESSION, L.P.
  
 Limited Liability Company Subsidiaries:
  
 CARMEN ACQUISITION, L.L.C.
 CHESAPEAKE ACQUISITION, L.L.C.
 CHESAPEAKE ENO ACQUISITION, L.L.C.
 CHESAPEAKE EP, L.L.C.
 CHESAPEAKE LAND COMPANY, L.L.C.
 CHESAPEAKE ORC, L.L.C.
 CHESAPEAKE PERMIAN ACQUISITION, L.L.C.



  

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	 CHESAPEAKE ROYALTY, L.L.C.
 GOTHIC
PRODUCTION, L.L.C.
 JOHN C. OXLEY, L.L.C.
 MC MINERAL COMPANY,
L.L.C.
 MAYFIELD PROCESSING, L.L.C.
  
 TRUSTEE:
  
 THE BANK OF NEW YORK TRUST COMPANY,
N.A., as Trustee

		
	By:	 	/s/ Steven D. Torgeson
	Name:	 	Steven. D. Torgeson
	Title:	 	Vice President


  

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