WHEREAS, the Company has requested that the Credit Agreement be amended to make certain changes to the Credit Agreement on the terms and conditions set forth in this Amendment; and

WHEREAS, all of the Lenders have agreed to such amendments subject to the terms and conditions set forth in this Amendment.

NOW, THEREFORE, in consideration of the mutual agreements, provisions and covenants contained herein and other good and valuable consideration, the receipt and adequacy of which are hereby acknowledged, the parties hereto, intending to be legally bound, hereby agree as follows:

Section 1.               Defined Terms; Interpretation.

(a)           Capitalized terms used but not otherwise defined herein shall have the meanings assigned such terms in the Credit Agreement.

(b)           The rules of interpretation set forth in Section 1.2 of the Credit Agreement are incorporated in this Amendment as if set forth herein.

Section 2.               Amendments.  The Credit Agreement is hereby amended as follows:

(a)           Section 8.4(h) is hereby amended and restated to read in its entirety as follows:

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“(h) acquisitions of proved Hydrocarbon Interests and related assets.”

(b)           Article VIII of the Credit Agreement is hereby amended by deleting the entirety of Section 8.24 and replacing the text thereof with “[Intentionally omitted].”

Section 3.               Amendment and Ratification.  Upon the effectiveness hereof as provided in Section 4 of this Amendment, this Amendment shall be deemed to be an amendment to the Credit Agreement, and the Credit Agreement, as modified hereby, is hereby ratified, approved and confirmed to be in full force and effect in each and every respect.  Except as expressly provided by the amendments set forth in Section 2 of this Amendment, the execution, delivery and effectiveness of this Amendment shall neither operate as a waiver of any right, power or remedy of any Lender or any Agent, nor constitute a waiver of any provision of any of the Loan Documents.  All references to the Credit Agreement in any other document, instrument, agreement or writing shall hereafter be deemed to refer to the Credit Agreement as amended hereby.

Section 4.               Conditions to Effectiveness.  The effectiveness of this Amendment is subject to the condition that, on or before the Amendment Effective Date, the Administrative Agent shall have received all of the following, in form and substance satisfactory to the Administrative Agent and each Required Lender, and in sufficient copies for each Lender:

(a)           Amendment.  This Amendment, duly executed and delivered by each of the Company, the Guarantors and the Required Lenders;

(b)           Payment of Fees.  Evidence of payment by the Company of all accrued and unpaid fees, costs and expenses owed pursuant to the Credit Agreement or this Amendment, in each case to the extent then due and payable at the Amendment Effective Date, including any such costs, fees and expenses arising under or referenced in Sections 2.8 and 11.4 of the Credit Agreement;

(c)           Certificate.  A certificate signed by a Responsible Officer, dated as of the Amendment Effective Date, stating that (i) the representations and warranties contained in Article VI and Section 4.5(b) of the Credit Agreement are true and correct on and as of the Amendment Effective Date, as though made on and as of such date; (ii) no litigation is pending or threatened against the Company or any Subsidiary in which there is a reasonable probability of an adverse decision which would result in a Material Adverse Effect; and (iii) there has occurred no event or circumstance that has resulted or would reasonably be expected to result in a Material Adverse Effect since December 31, 2004; and

(d)           Other Documents.  Such other approvals, opinions, documents or materials as the Administrative Agent or any Lender may reasonably request.

Section 5.               Representations and Warranties.  The Company and each Guarantor each hereby represent and warrant that, as of the Amendment Effective Date, after giving effect to this Amendment:

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(a)           Bring-Down of Representations and Warranties.  The representations and warranties of the Company and each Guarantor contained in Article VI and Section 4.5(b) of the Credit Agreement are true and correct on and as of the Amendment Effective Date, as though made on and as of such date.

(b)           No Litigation.  No litigation is pending or threatened against the Company or any Subsidiary in which there is a reasonable probability of an adverse decision which would result in a Material Adverse Effect.

(c)           No Material Adverse Effect.  There has occurred no event or circumstance that has resulted or would reasonably be expected to result in a Material Adverse Effect since December 31, 2004.

(d)           No Default or Event of Default.  No event has occurred and is continuing which constitutes a Default, an Event of Default or both.

Section 6.               Governing Law.  THIS AMENDMENT AND THE RIGHTS AND OBLIGATIONS OF THE PARTIES UNDER THIS AMENDMENT SHALL BE GOVERNED BY, AND CONSTRUED AND INTERPRETED IN ACCORDANCE WITH, THE LAW OF THE STATE OF NEW YORK.

Section 7.               Costs and Expenses.  The Company shall pay all reasonable costs and expenses incurred by the Administrative Agent or any other Agent, the Lenders or any of their Affiliates in connection with the development, preparation, administration and execution of this Amendment, including Attorney Costs incurred by any such Person with respect thereto.

Section 8.               Counterparts.  This Amendment may be executed in any number of separate counterparts, no one of which need be signed by all parties; each of which, when so executed, shall be deemed an original, and all of such counterparts taken together shall be deemed to constitute but one and the same instrument.  A fully executed counterpart of this Amendment by facsimile signatures shall be binding upon the parties hereto.

[Signature Pages Follow]

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IN WITNESS WHEREOF, the parties hereto have caused this Fourth Amendment to the Second Amended and Restated Credit Agreement be duly executed and delivered by their respective duly authorized officers as of the date first set forth above, to be effective as of the Amendment Effective Date.

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