<PAGE>   1
                                                                 EXHIBIT 10.23




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



                          FOURTH AMENDED AND RESTATED
                                CREDIT AGREEMENT

                                     among

                             COHO RESOURCES, INC.,

                       COHO LOUISIANA PRODUCTION COMPANY,

                             COHO EXPLORATION, INC.
                                      and
                           COHO ACQUISITIONS COMPANY

                                as the Borrowers


                               COHO ENERGY, INC.

                                 as a Guarantor


                          certain Lenders named herein


                         BANQUE PARIBAS, HOUSTON AGENCY

                          as the Administrative Agent

                                      and

                             BANK ONE, TEXAS, N.A.,
                                      and
                           MEESPIERSON CAPITAL CORP.

                           as Co-Documentation Agents

                               December 18, 1997




================================================================================
<PAGE>   2
                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                                                     Page
<S>                                                                                                                    <C>
ARTICLE I - DEFINITIONS; CERTAIN TERMS  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
         SECTION 1.01.  Definitions.  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
         SECTION 1.02.  Accounting and other Terms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  25

ARTICLE II - ADVANCES AND LETTERS OF CREDIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  26
         SECTION 2.01.  Commitments.  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  26
                 (a)      Revolving Advances  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  26
                 (b)      Letters of Credit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  26
         SECTION 2.02.  Notes.  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  27
         SECTION 2.03.  Repayment of Advances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  27
         SECTION 2.04.  Interest. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  27
         SECTION 2.05.  Access to Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  28
                 (a)      Borrowing Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  28
                 (b)      Procedure for Issuing Letters of Credit . . . . . . . . . . . . . . . . . . . . . . . . . .  29
         SECTION 2.06.  Use of Proceeds.  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  29
         SECTION 2.08.  Commitment Fee; Reduction or Termination of Commitments.  . . . . . . . . . . . . . . . . . .  30
         SECTION 2.09.  Additional Fees.  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  30
         SECTION 2.10.  Borrowing Base. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  31
                          (a)     Initial Amount; Waiver of Redetermination . . . . . . . . . . . . . . . . . . . . .  31
                          (b)     Semiannual Redeterminations.  . . . . . . . . . . . . . . . . . . . . . . . . . . .  31
                          (c)     Interim Redetermination by Lenders. . . . . . . . . . . . . . . . . . . . . . . . .  32
                          (d)     Interim Redeterminations at the Request of Borrowers  . . . . . . . . . . . . . . .  32
                          (e)     Redetermination as a Result of a Sale of Collateral . . . . . . . . . . . . . . . .  32
                          (f)     Standards for Redetermination . . . . . . . . . . . . . . . . . . . . . . . . . . .  33

ARTICLE III - PAYMENTS  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  33
         SECTION 3.01.  Method of Payment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  33
         SECTION 3.02.  Repayments and Prepayment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  34
                 (a)      Optional Repayments and Prepayments . . . . . . . . . . . . . . . . . . . . . . . . . . . .  34
                 (b)      Mandatory Prepayments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  34
         SECTION 3.03.  Pro Rata Treatment; Distribution of Payments  . . . . . . . . . . . . . . . . . . . . . . . .  35
                 (a)      Treatment.  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  35
                 (b)      Distribution of Payments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  35
         SECTION 3.04.  Non-Receipt of Funds by the Administrative Agent  . . . . . . . . . . . . . . . . . . . . . .  36
         SECTION 3.05.  Computation of Interest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  36
         SECTION 3.06.  Taxes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  36
                 (a)      Payment by Borrowers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  36
                 (b)      Withholding Tax Exemption Forms.  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  37

ARTICLE IV - YIELD PROTECTION AND ILLEGALITY  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  38
         SECTION 4.01.  Increased Costs and Reduced Return  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  38
</TABLE>





                                       i
<PAGE>   3
<TABLE>
<S>                                                                                                                    <C>
         SECTION 4.02.  Basis for Determining Interest Rate Inadequate or Unfair  . . . . . . . . . . . . . . . . . .  39
         SECTION 4.03.  Illegality  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  39
         SECTION 4.04.  Treatment of Affected Advances  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  39
         SECTION 4.05.  Funding Losses  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  40

ARTICLE V - CONDITIONS OF LENDING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  41
         SECTION 5.01.  Conditions to the Effectiveness of this Agreement . . . . . . . . . . . . . . . . . . . . . .  41
                 (a)      Amendment Fees; Payment of Fees . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  41
                 (b)      Representations and Warranties; No Event of Default . . . . . . . . . . . . . . . . . . . .  41
                 (c)      Legality  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  41
                 (d)      Delivery of Documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  41
         SECTION 5.02.  Conditions Precedent to the Advances and Issuances of Letters of Credit                        42
                 (a)      Payment of Fees, Etc  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  43
                 (b)      Representations and Warranties; No Event of Default . . . . . . . . . . . . . . . . . . . .  43
                 (c)      Legality  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  43
                 (d)      Advance Request Form  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  43
                 (e)      Proceedings; Receipt of Documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  43

ARTICLE VI - REPRESENTATIONS AND WARRANTIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  43
         SECTION 6.01.  Representations and Warranties of Each Company  . . . . . . . . . . . . . . . . . . . . . . .  43
                 (a)      Organization, Good Standing, Etc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  43
                 (b)      Authorization, Etc  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  44
                 (c)      Governmental Approvals  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  44
                 (d)      Enforceability of Loan Documents  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  44
                 (e)      Subsidiaries; Capitalization  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  44
                 (f)      Litigation  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  45
                 (g)      Financial Condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  45
                 (h)      Compliance with Law, Etc  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  45
                 (i)      ERISA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  45
                 (j)      Taxes, Etc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  46
                 (k)      Regulation U  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  46
                 (l)      Title to Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  46
                 (m)      Credit Arrangements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  46
                 (n)      Nature of Business  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  46
                 (o)      Adverse Agreements, Etc.  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  46
                 (p)      Holding Company and Investment Company Acts . . . . . . . . . . . . . . . . . . . . . . . .  47
                 (q)      Permits, Etc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  47
                 (r)      Full Disclosure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  47
                 (s)      Environmental Conditions  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  47
                 (t)      Principal Place of Business; Location of Collateral . . . . . . . . . . . . . . . . . . . .  48
                 (u)      Corporate Name  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  49
                 (v)      Security Interests and Liens  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  49

ARTICLE VII - COVENANTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  49
</TABLE>





                                       ii
<PAGE>   4
<TABLE>
<S>                                                                                                                    <C>
         SECTION 7.01.  Affirmative Covenants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  49
                 (a)      Stockholders' Equity  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  49
                 (b)      Interest Coverage Ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  49
                 (c)      Current Ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  50
                 (d)      Reporting Requirements  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  50
                 (e)      Compliance with Laws, Etc.  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  53
                 (f)      Preservation of Existence, Etc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  54
                 (g)      Maintenance of Properties, Etc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  54
                 (h)      Obtaining of Permits, Etc.  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  54
                 (i)      Keeping of Records and Books of Account . . . . . . . . . . . . . . . . . . . . . . . . . .  54
                 (j)      Inspection Rights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  55
                 (k)      Environmental Laws  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  55
                 (l)      Environmental Reports and Compliance  . . . . . . . . . . . . . . . . . . . . . . . . . . .  55
                 (m)      Further Assurances; Post Closing Matters; Letters in Lieu . . . . . . . . . . . . . . . . .  56
                 (n)      Unrestricted Subsidiaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  56
         SECTION 7.02.  Negative Covenants  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  57
                 (a)      Liens, Etc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  57
                 (b)      Indebtedness  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  59
                 (c)      Merger, Consolidation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  61
                 (d)      Sale of Assets, Etc.  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  61
                 (e)      Change in Nature of Business  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  62
                 (f)      Transactions with Affiliates  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  62
                 (g)      Restricted Payments and Restricted Investments  . . . . . . . . . . . . . . . . . . . . . .  63
                 (h)      Financial Covenants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  63
                 (i)      Hedging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  64

ARTICLE VIII - EVENTS OF DEFAULT  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  64
         SECTION 8.01.  Events of Default . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  64
         SECTION 8.02. Remedies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  66
                 (a)      Acceleration  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  66
                 (b)      Termination of Commitments  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  67
                 (c)      Judgment  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  67
                 (d)      Foreclosure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  67
                 (e)      Rights  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  67
         SECTION 8.03.  Performance by the Administrative Agent . . . . . . . . . . . . . . . . . . . . . . . . . . .  67

ARTICLE IX - THE ADMINISTRATIVE AGENT AND THE CO-DOCUMENTATION AGENTS . . . . . . . . . . . . . . . . . . . . . . . .  68
         SECTION 9.01.  Appointment, Powers and Immunities of Co-Documentation Agent Agents . . . . . . . . . . . . .  68
         SECTION 9.02.  Rights of Co-Documentation Agents as a Lender . . . . . . . . . . . . . . . . . . . . . . . .  69
         SECTION 9.03.  Sharing of Payments, Etc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  70
         SECTION 9.04.  Indemnification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  70
         SECTION 9.05.  Independent Credit Decisions  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  71
         SECTION 9.06.  Several Commitments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  71
</TABLE>





                                      iii
<PAGE>   5
<TABLE>
<S>                                                                                                                    <C>
         SECTION 9.07.  Successor Administrative Agent  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  72

ARTICLE X - MISCELLANEOUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  72
         SECTION 10.01.  Notices, Etc.  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  72
         SECTION 10.02.  Amendments, Etc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  72
         SECTION 10.03.  No Waiver; Remedies, Etc.  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  73
         SECTION 10.04.  Fees, Costs, Expenses and Taxes  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  73
         SECTION 10.05.  Indemnity  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  74
                 (a)      Environmental Indemnity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  74
                 (b)      General Indemnity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  74
                 (c)      Provisions Applicable to All Indemnities  . . . . . . . . . . . . . . . . . . . . . . . . .  75
         SECTION 10.06.  Right of Set-off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  75
         SECTION 10.07.  Severability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  75
         SECTION 10.08.  Successors and Assigns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  75
                 (a)      Binding Effect  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  75
                 (b)      Participation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  76
                 (c)      Assignments by Lenders  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  76
                 (d)      Deliveries of Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  77
         SECTION 10.09.  Counterparts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  77
         SECTION 10.10.  Headings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  77
         SECTION 10.11.  Governing Law  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  77
         SECTION 10.12.  WAIVER OF JURY TRIAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  77
         SECTION 10.13.  Maximum Interest Rate  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  77
         SECTION 10.14.  Non-Application of Chapter 15 of Texas Credit Code . . . . . . . . . . . . . . . . . . . . .  78
         SECTION 10.15.  Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  78
         SECTION 10.16.  Confidentiality  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  78
         SECTION 10.17.  Survival . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  79
         SECTION 10.18.  Joint and Several Obligations  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  79
         SECTION 10.19.  ENTIRE AGREEMENT; AMENDMENT
                                AND RESTATEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  79
</TABLE>





                                       iv
<PAGE>   6
                                    EXHIBITS

<TABLE>
         <S>                      <C>
         Exhibit A        -       Note
         Exhibit B        -       Advance Request Form
         Exhibit C        -       Solvency Certificate
         Exhibit D        -       Local Counsel Opinion
</TABLE>


                                   SCHEDULES

<TABLE>
         <S>              <C>
         6.01(e) -        Subsidiaries
         6.01(f) -        Litigation
         6.01(m) -        Credit Agreements
         6.01(s) -        Environmental Matters
         6.01(t) -        Locations of Business and Collateral
         7.02(a) -        Liens
         7.02(f) -        Affiliate Transactions
</TABLE>





                                       v
<PAGE>   7
                  FOURTH AMENDED AND RESTATED CREDIT AGREEMENT

         FOURTH AMENDED AND RESTATED CREDIT AGREEMENT (the "Agreement") dated
as of December 18, 1997 by and among COHO RESOURCES, INC., a Nevada corporation
("CRI"), COHO LOUISIANA PRODUCTION COMPANY, a Delaware corporation (the
"Production Company"), COHO EXPLORATION, INC., a Delaware corporation
("Exploration") COHO ACQUISITIONS COMPANY, a Delaware corporation
("Acquisitions"), (CRI, the Production Company, Exploration and Acquisitions
are sometimes collectively referred to as the "Borrowers" and individually as a
"Borrower"), COHO ENERGY, INC., a Texas corporation ("Holdings") (the Borrowers
and Holdings are sometimes referred to herein together as the "Companies" or
individually as a "Company"), each of the banks or other lending institutions
which is or which may from time to time become a signatory hereto or any
successor or assignee thereof (collectively, the "Lenders"), BANQUE PARIBAS, a
bank organized under the laws of the Republic of France acting through its
Houston Agency ("PARIBAS") in its capacity as Administrative Agent for the
Lenders (in such capacity, together with its successors in such capacity, the
"Administrative Agent"), and BANK ONE, TEXAS, N.A., a national banking
association ("Bank One"), and MEESPIERSON CAPITAL CORP., a Delaware corporation
("MeesPierson"), as Co-Documentation Agents for the Lenders (Bank One and
MeesPierson in such capacities, together with their successors in such
capacities,  the "Co-Documentation Agents").

                                R E C I T A L S:

         A.      CRI and Canada Trust Bank N.V. formerly known as The Canada
Trust Company B.V. (herein, "Canada Trust") entered into that certain Revolving
Credit Agreement dated as of August 16, 1990 (such agreement, as the same has
been amended, hereinafter referred to as the "Canada Trust Credit Agreement").
To evidence the indebtedness of CRI to Canada Trust under the Canada Trust
Credit Agreement, CRI executed and delivered to Canada Trust that certain
Promissory Note dated August 16, 1990, payable to the order of Canada Trust in
the original principal amount of $75,000,000.00 (the "Canada Trust Note").

         B.      Canada Trust has assigned to the Administrative Agent for the
benefit of the Lenders, Canada Trust's right, title and interest in and to,
among other things, the Canada Trust Credit Agreement, the Canada Trust Note,
the security agreements, mortgages and other collateral documents securing
payment thereof (all such documentation referred to collectively herein as the
"Canada Trust Loan Documents") pursuant to that certain Assignment of Note,
Loan Documents and Liens dated as of August 27, 1992, executed by Canada Trust
for the benefit of the Administrative Agent and the Lenders (such assignment
hereinafter referred to as the "Assignment").

         C.      CRI has entered into that certain Credit Agreement dated as of
August 27, 1992 (such agreement, as the same has been modified, herein the
"Original Credit Agreement") with the Administrative Agent, Canada Trust and
the other Lenders named therein, to amend and restate the Canada Trust Credit
Agreement in its entirety.

         D.      Canada Trust has assigned all its interest in the Original
Credit Agreement pursuant to the following:





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 1
<PAGE>   8
              (i)         that certain Assignment Agreement dated June 10, 1993
                          among Canada Trust, PARIBAS and the Administrative
                          Agent;

             (ii)         that certain Assignment Agreement dated October 22,
                          1993 among Canada Trust, MeesPierson and the
                          Administrative Agent;

            (iii)         that certain Assignment Agreement dated November 5,
                          1993 among Canada Trust, Bank of Scotland and the
                          Administrative Agent;

             (iv)         that certain Assignment Agreement dated November 5,
                          1993 among Canada Trust, Wells Fargo Bank, N.A. and
                          the Administrative Agent; and

              (v)         that certain Assignment Agreement dated November 5,
                          1993 among Canada Trust, Christiania Bank OG
                          Kreditkasse and the Administrative Agent.

         E.      The Original Credit Agreement has been amended and restated in
its entirety by that certain Amended and Restated Credit Agreement dated as of
February 8, 1994, by and among CRI, Holdings, Paribas, as Agent, and the
Lenders parties thereto (as amended by that certain First Amendment to Amended
and Restated Credit Agreement dated as of June 24, 1994, the "First Amended
Credit Agreement").

         F.      The First Amended Credit Agreement has been amended and
restated in its entirety by that certain Second Amended and Restated Credit
Agreement dated as of December 2, 1994, by and among CRI, Holdings, Paribas, as
Agent, and the Lenders parties thereto (as amended by that certain First
Amendment to Second Amended and Restated Credit Agreement dated as of June 30,
1995, that certain Second Amendment to Second Amended and Restated Credit
Agreement dated as of August 4, 1995, that certain Third Amendment to Second
Amended and Restated Credit Agreement dated as of November 1, 1995, and that
certain Fourth Amendment to Second Amended and Restated Credit Agreement dated
as of March 29, 1996, the "Second Amended Credit Agreement").

         G.      The Second Amended Credit Agreement has been amended and
restated in its entirety by that certain Third Amended and Restated Credit
Agreement dated as of August 8, 1996, by and among CRI, Holdings, Paribas, as
Agent, and the Lenders parties thereto (as amended by that certain First
Amendment to Third Amended and Restated Credit Agreement dated as of October 1,
1997, the "Second Amended Credit Agreement").

         H.      CRI has requested that the Administrative Agent and the
Lenders amend the Third Amended Credit Agreement (i) to increase the amount of
the facility, (ii) to permit the increase of facility proceeds to be used to
acquire certain properties located in Oklahoma, (iii) to extend the Maturity
Date to December 18, 2002, and (iv) to modify certain other provisions of the
Third Amended Credit Agreement.  The Lenders and the Administrative Agent are
willing to make such amendments to the Third Amended Credit Agreement upon and
subject to the terms and conditions of the Third Amended Credit Agreement as
amended and restated hereby.





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 2
<PAGE>   9
         NOW THEREFORE, in consideration of the premises and the mutual
covenants herein contained, the parties hereto agree as follows:

                                   ARTICLE I

                           DEFINITIONS; CERTAIN TERMS

         SECTION 1.01.  Definitions.  As used in this Agreement, the following
terms shall have the respective meanings indicated below, such meanings to be
applicable equally to both the singular and plural forms of such terms:

         "Acquisition Engineering Report" means the Engineering Report prepared
by Sproule Associates, Inc., dated November 19, 1997, covering the Amoco
Properties.

         "Acquisitions" has the meaning specified in the preamble hereto.

         "Additional Security Agreement" means the Security Agreement dated
February 8, 1994, between CRI and the Administrative Agent for the benefit of
Lenders, as the same may be amended or otherwise modified from time to time.

         "Adjusted Eurodollar Rate" means, for any Eurodollar Advance for any
Interest Period therefor, the rate per annum (rounded upwards, if necessary, to
the nearest 1/100 of 1%) determined by the Administrative Agent to be equal to
the Interbank Offered Rate for such Eurodollar Advance for such Interest Period
divided by 1 minus the Reserve Requirement for such Eurodollar Advance for such
Interest Period.

         "Administrative Agent" has the meaning specified in the preamble
hereto.

         "Advance" means a Revolving Advance.

         "Advance Request Form" means a certificate, in substantially the form
of Exhibit B hereto, properly completed and signed by a Borrower requesting an
Advance or the issuance of a Letter of Credit.

         "Affiliate" means, as to any Person, (a) any other Person that
directly or indirectly through one or more intermediaries, controls, is
controlled by, or is under common control with, such Person or (b) when used
with respect to all covenants, representations, warranties and other provisions
relating to ERISA and ERISA related matters, the term "Affiliate" shall only
mean, as to any Person, any trade or business (whether or not incorporated)
which is a member of a group of which such Person is a member and which is
under common control within the meaning of the regulations promulgated under
Section 414 of the Internal Revenue Code.  The term "control" means the
possession, directly or indirectly, of the power to direct or cause direction
of the management and policies of a Person, whether through the ownership of
voting securities, by contract, or otherwise; provided, however, in no event
shall the Administrative Agent, any Co-Documentation Agent or any Lender be
deemed an Affiliate of Holdings or any of its Subsidiaries.





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 3
<PAGE>   10
         "Agreement"  means this Fourth Amended and Restated Credit Agreement
as the same may be amended or otherwise modified.

         "Amoco" means Amoco Production Company, a Delaware corporation and
party to the Amoco Purchase Agreement.

         "Amoco Properties" means the Petroleum and Natural Gas Rights and
other real and personal property to be purchased by Acquisitions from Amoco
Production Company pursuant to the Amoco Purchase Agreement.

         "Amoco Purchase Agreement" means that certain Purchase and Sale
Agreement between Amoco Production Company and Acquisitions, dated November 26,
1997.

         "Applicable Lending Office" means for each Lender and each Type of
Advance, the Lending Office of such Lender (or of an Affiliate of such Lender)
designated for such Type of Advance below its name on the signature pages
hereof or such other office of such Lender (or of an Affiliate of such Lender)
as such Lender may from time to time specify to the Borrowers and the
Administrative Agent as the office from which its Advances of such Type are to
be made and maintained.

         "Applicable Margin" for Revolving Advances means (a) with respect to
Prime Rate Advances, zero percent (0.00%) and (b) with respect to Eurodollar
Advances, one and one-half of one percent (1.50%); provided however, that the
Applicable Margin for Eurodollar Advances shall be adjusted based upon the
ratio of the Consolidated Indebtedness of Holdings and its Restricted
Subsidiaries to the EBITDA of Holdings and its Restricted Subsidiaries
(measured on a rolling four-quarters basis) as follows:

<TABLE>
<CAPTION>
   CONSOLIDATED                        APPLICABLE MARGIN FOR
INDEBTEDNESS/EBITDA                     EURODOLLAR ADVANCES
<S>                                    <C>
      <2.0                                     1.000%

  > 2.0 X <2.5                                 1.125%
  -
  > 2.5 X <3.0                                 1.250%
  -
  > 3.0 X <3.5                                 1.375%
  -
     > 3.5X                                    1.500%
     -
</TABLE>

Changes in the Applicable Margin for Eurodollar Advances shall be based upon
such ratio of Consolidated Indebtedness to EBITDA of Holdings and its
Restricted Subsidiaries as disclosed in the certified quarterly or annual
audited consolidated financial statements of Holdings delivered to the
Administrative Agent pursuant to Section 7.01(d) and calculated in the
officer's certificate delivered concurrently therewith pursuant to Section
7.01(d)(iv) and shall become effective on delivery of such financial statements
and certificate to the Administrative Agent. Provided, however, for the period
from the Closing Date until March 31, 1998, the Applicable Margin for





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 4
<PAGE>   11
Eurodollar Advances shall be 1.50%, and for the next three calendar quarters of
1998, the Applicable Margin for Eurodollar Advances shall be computed on the
basis of the ratio of the Consolidated Indebtedness of Holdings and its
Restricted Subsidiaries to the EBITDA of Holdings and its Restricted
Subsidiaries for the prior calendar quarters of 1998 alone computed on an
annualized basis, so that (i) the calculation for March 31, 1998 shall be made
solely with respect to EBITDA for the calendar quarter ending March 31, 1998
which shall be multiplied times four, (ii) the calculation for June 30, 1998
shall be made with respect to EBITDA for the two calendar quarters ending June
30, 1998 which shall be multiplied times two, (iii) the calculation for
September 30, 1998 shall be made with respect to EBITDA for the three calendar
quarters ending September 30, 1998 which shall be multiplied times four/thirds,
and (iv) thereafter the calculation shall be made on a rolling four quarters
basis as having been done prior to the Closing Date.

         "Applicable Rate" means:  (a) during the period that an Advance is a
Prime Rate Advance, the Prime Rate plus the Applicable Margin, and (b) during
the period that an Advance is a Eurodollar Advance, the Adjusted Eurodollar
Rate plus the Applicable Margin.

         "Assignment" has the meaning specified in the Recitals hereto.

         "Authorizing Resolution" means that certain Coho Energy, Inc.
Statement of Resolution Establishing Series of Shares filed in accordance with
the terms of the ING Acquisition Agreement.

         "Availability" means, at the date of determination, the difference
between (a) the Borrowing Base as of such date, and (b) the Outstanding Credit
as of such date.

         "Borrower" and "Borrowers" have the meanings specified in the preamble
hereto.

         "Borrowing Base" means the Dollar amount determined in accordance with
Section 2.10 which shall never exceed the aggregate amount of the Commitments.

         "Borrowing Date" means the date on which an Advance is made or Letter
of Credit is issued hereunder.

         "Business Day" means (a) any day on which commercial banks are not
authorized or required to close in Houston, Texas and New York, New York and
(b) with respect to all borrowings, payments, Conversions, Continuations,
Interest Periods, and notices in connection with Eurodollar Advances, any day
which is a Business Day described in clause (a) above and which is also a day
on which dealings in Dollar deposits are carried out in the London interbank
market.

         "Canada Trust" has the meaning specified in the Recitals hereto.

         "Canada Trust Credit Agreement " has the meaning specified in the
Recitals hereto.

         "Canada Trust Loan Documents" has the meaning specified in the
Recitals hereto.





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 5
<PAGE>   12
         "Canada Trust Note" has the meaning specified in the Recitals hereto.

         "Capitalized Lease Obligations" means obligations for the payment of
rent for any real or personal property under leases or agreements to lease that
in accordance with GAAP have been or should be capitalized on the books of the
lessee and, for purposes hereof, the amount of any such obligation shall be the
capitalized amount thereof determined in accordance with GAAP.

         "Capital Stock" means any and all shares, interests, participation,
rights or other equivalents (however designated) evidencing equity interests in
an issuing entity.

         "Change of Control" means the occurrence of the following:  any Person
or two or more Persons acting as a group (as defined in Section 13d-3 of the
Securities Exchange Act of 1934) shall have acquired beneficial ownership
(within the meaning of Rule 13d-3 of the Securities and Exchange Commission
under the Securities Exchange Act of 1934) of thirty percent (30%) or more of
the outstanding shares of voting stock of Holdings.

         "Closing Date" means December 18, 1997.

         "Coho Canada" means Coho Resources Limited, an Alberta, Canada
corporation and Subsidiary of Holdings.

         "Coho Canada Negative Pledge" means the Negative Pledge Agreement
dated as of February 8, 1994, between Coho Canada and the Administrative Agent
for the benefit of Lenders as the same may be amended or otherwise modified
from time to time.

         "Coho Shell" means Coho Shell Company, a Delaware corporation.

         "Co-Documentation Agents" means Bank One and MeesPierson in their
capacities as Co-Agents for the Lenders.

         "Collateral" means all of the property (tangible and intangible)
purported to be subject to the Liens of the Security Documents.

         "Commitment" means the obligation of each Lender to make Advances
hereunder in an aggregate principal amount at any one time outstanding up to
but not exceeding the amount set forth opposite the name of such Lender on the
signature pages hereto under the heading "Commitment," as such amount may be
reduced pursuant to Section 2.08, and "Commitments" means all such commitments
of all of the Lenders, the aggregate of which on the Closing Date equals
$300,000,000.

         "Company" and "Companies" have the meanings specified in the preamble
hereto.

         "Consolidated Current Assets", as of any date of determination, means
all assets of Holdings and its Restricted Subsidiaries which would properly be
characterized as current assets on a balance sheet prepared in accordance with
GAAP as of such date, plus the Availability as of such date.





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 6
<PAGE>   13
         "Consolidated Current Liabilities" means, as of any date of
determination, all liabilities of Holdings and its Restricted Subsidiaries
which would properly be characterized as current liabilities on a balance sheet
prepared in accordance with GAAP as of such date.

         "Consolidated Current Ratio" means as of the date of determination,
the ratio of Consolidated Current Assets to Consolidated Current Liabilities as
of such date.

         "Consolidated Indebtedness" means, for any Person, all Indebtedness of
such Person and its Restricted Subsidiaries determined on a consolidated basis
in accordance with GAAP.

         "Consolidated Interest Expense" means, for any period, all interest on
Indebtedness of Holdings and its Restricted Subsidiaries paid or accrued during
such period, including the interest portion of payments under Capital Lease
Obligations.

         "Consolidated Net Income" means, for any period and for any Person,
the consolidated net income of such Person and its Restricted Subsidiaries for
such period determined in accordance with GAAP.

         "Contaminant" means those substances which are regulated by or form
the basis of liability under any Environmental Law, including, without
limitation, asbestos, polychlorinated biphenyls ("PCBs"), Hazardous Materials,
pollutants, chemicals or any other material or substance which now or in the
future constitutes or is deemed by a Governmental Authority to constitute a
health, safety, or environmental hazard to any Person or property.

         "Continue", "Continuation", and "Continued" shall refer to the
continuation pursuant to Section 2.07 of a Eurodollar Advance as a Eurodollar
Advance from one Interest Period to the next Interest Period.

         "Contribution and Reimbursement Agreement" means that certain
Contribution and Reimbursement Agreement dated as of December 2, 1994, among
the Credit Parties, as amended and restated pursuant to that certain Amended
and Restated Contribution and Reimbursement Agreement dated as of August 8,
1996 among the Credit Parties, as the same may be amended or otherwise modified
from time to time.

         "Convert", "Conversion", and "Converted" shall refer to a conversion
pursuant to Section 2.07 or Article IV of one Type of Advance into another Type
of Advance.

         "CRI Pledge Agreement" means the Pledge Agreement dated as of December
2, 1994, pursuant to which CRI pledged to the Administrative Agent, for the
benefit of the Lenders, the Capital Stock of ING owned by CRI as collateral for
the Obligations, as the same may be amended or otherwise modified from time to
time.

         "Credit Parties" means, collectively, the Companies, Coho Canada, ING
and the ING Subsidiaries.





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 7
<PAGE>   14
         "Daily Production of Crude Oil" means an amount equal to the
Borrowers' actual average daily production of crude oil for the thirty (30) day
period ending on the applicable date of determination.

         "Daily Production of Natural Gas" means an amount equal to the
Borrowers' actual average daily production of natural gas for the thirty (30)
day period ending on the applicable date of determination.

         "Deed of Trust" means that certain Deed of Trust, Mortgage,
Assignment, Security Agreement and Financing Statement dated December 11, 1990,
made by CRI for the benefit of Canada Trust encumbering the various real and
personal properties described therein located in Texas, as assigned to the
Administrative Agent for the benefit of the Lenders pursuant to the Assignment,
as amended pursuant to that certain First Renewal, Extension and Modification
of Deed of Trust, Mortgage, Assignment, Security Agreement and Financing
Statement dated August 27, 1992, that certain Second Modification of Deed of
Trust, Mortgage, Assignment, Security Agreement and Financing Statement dated
January 6, 1993, Third Renewal, Extension and Modification of Deed of Trust,
Mortgage, Assignment, Security Agreement and Financing Statement dated June 24,
1994, the Fourth Modification of Texas Deed of Trust and as the same may
hereafter be amended or otherwise modified.

         "Default Rate" means the lesser of (i) the Maximum Rate or (ii) the
sum of the Prime Rate in effect from day to day plus four percent (4%).

         "Dollars" and "$" means lawful money of the United States of America.

         "EBITDA" means, for any period, without duplication, the sum of the
following for Holdings and its Restricted Subsidiaries determined on a
consolidated basis in accordance with GAAP: (a) Consolidated Net Income, plus
(b) Consolidated Interest Expense, plus (c) income, franchise and other taxes
(excluding taxes related to the production of Hydrocarbons) to the extent
deducted in determining Consolidated Net Income, plus (d) depreciation and
amortization expense and other non-cash items to the extent deducted in
determining Consolidated Net Income, minus (e) non-cash income to the extent
included in determining Consolidated Net Income.

         "Employee Plan" means an employee benefit plan (other than a
Multiemployer Plan) covered by Title IV of ERISA and maintained for employees
of Holdings or any of its Affiliates.

         "Engineering Report" means a report, in form and substance reasonably
satisfactory to the Lenders, certified by, in the case of an Annual Engineering
Report described in Section 2.10(b), an Independent Engineer and by the chief
financial officer of CRI and, in the case of a Semi-Annual Engineering Report
described in Section 2.10(b), by the chief financial officer of CRI or the
chief financial officer of CRI and an Independent Engineer, as the case may be,
addressed to the Administrative Agent for the benefit of the Lenders setting
forth, with respect to the Petroleum and Natural Gas Rights of the Borrowers
(or to be acquired by the Borrowers, as applicable) which are or are to be
Collateral, (a) the location, quantity and type of the estimated Proven
Reserves applicable to such Petroleum and Natural Gas Rights, (b) a projection
of the rate of production of





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 8
<PAGE>   15
such Proven Reserves, (c) an estimation of the net operating revenues to be
derived from the production and sale of Hydrocarbons from such Proven Reserves
and (d) such other information as is customarily obtained from and provided in
such reports or is otherwise reasonably requested to be contained in such
reports by the Required Lenders.

         "Environmental Claim" means any notice of violation, claim, demand,
order, directive or cause of action by any Governmental Authority or any Person
for personal injury (including, without limitation, sickness, disease or
death), tangible or intangible property damage, damage to the environment,
nuisance, pollution, contamination or other adverse effects on the environment,
or for fines, penalties or restrictions, resulting from or based upon (a) the
existence, or the continuation of the existence, of a Release (including,
without limitation, sudden or non-sudden, accidental or nonaccidental Releases)
or exposure to any Contaminant, odor or audible noise, (b) the transportation,
storage, treatment or disposal of Contaminants in connection with the operation
of facilities or (c) the violation or alleged violation of any Environmental
Law.

         "Environmental Law" means any and all applicable past, present and
future laws, regulations, enforceable requirements, binding determinations,
orders, decrees, judgments, injunctions, permits, approvals, authorizations,
licenses, variances, permissions, notices or binding agreements issued,
promulgated or entered by any Governmental Authority, relating to the
environment, health, safety preservation or reclamation of natural resources,
historic structures and places, or to a Release or threatened Release, or any
noxious noise or odor, including, without limitation, those relating to
manufacturing, processing, registering, introducing into commerce, labeling,
distributing, using, generating, treating, storing, disposing, transporting or
handling of any regulated material.

         "Environmental Permit" means any permit, authorization, approval or
other consent required to be obtained under any Environmental Law.

         "ERISA" means the Employee Retirement Income Security Act of 1974, as
amended from time to time, and, unless the context otherwise requires, the
rules and regulations promulgated thereunder from time to time.

         "Eurodollar Advances" means Advances that bear interest at rates based
on the rates referred to in the definition of "Adjusted Eurodollar Rate" in
this Section 1.01.

         "Event of Default" means any of the events set forth in Section 8.01
hereof.

         "Federal Funds Rate" means, for any day, the rate per annum (rounded
upwards, if necessary, to the nearest 1/100 of 1%) equal to the weighted
average of the rates on overnight Federal funds transactions with members of
the Federal Reserve System arranged by Federal funds brokers on such day, as
published by the Federal Reserve Bank of New York on the Business Day next
succeeding such day, provided however, that (a) if the day for which such rate
is to be determined is not a Business Day, the Federal Funds Rate for such day
shall be such rate on such transactions on the next preceding Business Day as
so published on the next succeeding Business Day and (b) if such rate is not so
published on such next succeeding Business Day, the Federal Funds Rate for any
day shall





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 9
<PAGE>   16
be the average rate charged to the Reference Lenders on such day on such
transactions as determined by the Administrative Agent.

         "Financial Statements" means the audited consolidated financial
statements of Holdings as of December 31, 1996 and the related statement of
earnings, cash flow and shareholders' equity for the year ending December 31,
1996, together with the notes thereto.

         "First Amended and Restated Modification Agreement" means that certain
First Amended and Restated Modification Agreement dated of even date herewith
among the Companies, the other Guarantors, Coho Canada and the Administrative
Agent.

         "First Amended Credit Agreement" has the meaning specified in the
Recitals hereto.

         "First Amendment to Holdings Pledge Agreement" means the First
Amendment to Pledge Agreement dated as of December 2, 1994, pursuant to which
Holdings pledged to the Administrative Agent, for the benefit of the Lenders,
the Capital Stock of ING owned by Holdings as collateral for the Obligations,
as the same may be amended or otherwise modified from time to time.

         "GAAP" means generally accepted accounting principles, applied on a
consistent basis, as set forth in opinions of the Accounting Principles Board
of the American Institute of Certified Public Accountants and/or in statements
of the Financial Accounting Standards Board and/or their respective successors
and which are applicable in the circumstances as of the date in question.
Accounting principles are applied on a "consistent basis" when the accounting
principles observed in a current period are comparable in all material respects
to those accounting principles applied in a preceding period.

         "Governmental Authority" means the United States or any state or
political subdivision thereof or any foreign nation or political subdivision
thereof, any entity, body or authority exercising executive, legislative,
judicial, regulatory or administrative functions of, or pertaining to,
government in the United States (or any state or political subdivision thereof)
or any foreign nation or any political subdivision thereof, including, without
limitation, any central bank or other governmental or quasi-governmental
authority exercising control over banks or other financial institutions, and
any corporation or other entity or authority owned or controlled (through stock
or capital ownership or otherwise) by any of the foregoing.

         "Guarantors" means Holdings, ING, Coho Fairbanks Gathering Company and
Coho Louisiana Gathering Company.

         "Hazardous Materials" means all materials subject to any Environmental
Law, including, without limitation, materials listed in 49 C.F.R. Section
172.101, materials defined as hazardous pursuant to Section 101(14) of the
Comprehensive Environmental Response, Compensation and Liability Act of 1980,
as amended, explosive or regulated radioactive materials or substances,
pollutants, contaminants, hazardous or toxic wastes or substances, petroleum or
petroleum distillates or asbestos or material containing asbestos.





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 10
<PAGE>   17
         "Hedging Arrangements" means any hedging accounts or hedging contracts
relating to the trading of crude oil or natural gas that are established or
maintained by any Credit Party to limit or reduce the market risk of holding
crude oil or natural gas in either the cash or futures market.

         "Holdings" has the meaning specified in the preamble hereto.

         "Holdings Guaranty" means the Guaranty Agreement dated as of February
8, 1994, executed and delivered by Holdings for the benefit of the
Administrative Agent and the Lenders, as the same may be amended or otherwise
modified from time to time.

         "Holdings Pledge Agreement" means the Pledge Agreement dated as of
February 8, 1994, between Holdings and the Administrative Agent, as amended by
the First Amendment to Holdings Pledge Agreement and as the same may be further
amended or otherwise modified from time to time.

         "Hydrocarbons" means crude oil, natural gas, natural gas liquids,
other liquid or gaseous hydrocarbons and sulphur.

         "Indebtedness" means, with respect to any Person, (a) all indebtedness
or other obligations of such Person for borrowed money or for the deferred
purchase price of property or services except trade accounts payable incurred
in the ordinary course of business which are not past due by more than one
hundred twenty (120) days unless they are being contested in good faith by
appropriate proceedings, (b) Capitalized Lease Obligations of such Person, (c)
all obligations of such Person under direct or indirect guaranties in respect
of, and contingent or other obligations of such Person to purchase or otherwise
acquire or to otherwise assure a creditor against loss in respect of,
indebtedness or other obligations of any other Person for borrowed money or for
the deferred purchase price of property or services or Capitalized Lease
Obligations of any other Person, (d) all indebtedness or other obligations of
any other Person for borrowed money or for the deferred purchase price of
property or services secured by (or for which the holder of such indebtedness
has an existing right, contingent or otherwise, to be secured by) any lien,
security interest or other charge or encumbrance upon or in property owned by
such Person, (e) all obligations of such Person in respect of letters of credit
and bankers' acceptances, (f) liabilities (other than premiums to the Pension
Benefit Guaranty Corporation under Title IV of ERISA) incurred under Title IV
of ERISA with respect to any plan (other than a Multiemployer Plan) covered by
Title IV of ERISA and maintained for employees of such Person or any of its
Affiliates and (g) withdrawal liability incurred under ERISA by such Person or
any of its Affiliates to any Multiemployer Plan.

         "Indenture" means that certain Indenture dated as of October 1, 1997,
executed and delivered by Holdings, as issuer, the Borrowers, ING, Coho
Fairbanks Gathering Company and Coho Louisiana Gathering Company, as subsidiary
guarantors, and Marine Midland Bank, as Trustee, as the same may be amended or
otherwise modified with the consent of Required Lenders.





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 11
<PAGE>   18
         "Independent Engineer" means Ryder Scott Company or another
independent engineering firm selected by the Borrowers and reasonably
satisfactory to the Lenders; provided however, that, if the Borrowers shall not
have selected an independent engineering firm satisfactory to the Lenders
within thirty (30) days of receiving notice from the Administrative Agent
requesting a different engineering firm, the Administrative Agent shall furnish
to the Borrowers a list of three alternative engineering firms and "Independent
Engineer" shall mean the engineering firm selected by the Borrowers from such
list.

         "ING" means Interstate Natural Gas Company, a Delaware corporation.

         "ING Acquisition" means the acquisition of ING by Holdings and CRI
pursuant to the ING Acquisition Agreement.

         "ING Acquisition Agreement" means that certain Acquisition Agreement
dated as of November 11, 1994, by and among The Morgan Stanley Leveraged Equity
Fund II, L.P., Quinn Oil Company Ltd., ING, Holdings and CRI.

         "ING Pledge Agreement" means the Pledge Agreement dated as of December
2, 1994, pursuant to which ING pledged to the Administrative Agent, for the
benefit of the Lenders, the Capital Stock of the ING Subsidiaries directly
owned by ING as collateral for the Obligations, as the same may be amended or
otherwise modified from time to time.

         "ING Subsidiaries" means the Production Company, Coho Fairbanks
Gathering Company, Coho Louisiana Gathering Company and Exploration.

         "Initial Engineering Report" means the engineering report prepared by
The Scotia Group, dated June 1992.

         "Initial Environmental Report" means the Phase 1 environmental report
delivered to the Administrative Agent in accordance with Section 5.01(e)(xvii)
of the Original Credit Agreement.

         "Interbank Offered Rate" means, with respect to each Interest Period,
the rate of interest per annum determined by the Administrative Agent to be the
average (rounded upward, if necessary, to the nearest 1/100 of 1%) of the rates
per annum at which deposits in immediately available freely transferable funds
in Dollars are offered to each of the Reference Lenders (at approximately 11:00
a.m., London, England time, two Business Days prior to the first day of such
Interest Period) in the London interbank market for delivery on the first day
of such Interest Period, such deposits being for a period of time equal or
comparable to such Interest Period and in an amount equal or comparable to each
Reference Lender's share of the principal amount of the Eurodollar Advance to
which such Interest Period relates.  Each determination by the Administrative
Agent of the Interbank Offered Rate shall be conclusive in the absence of
manifest error.





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 12
<PAGE>   19
         "Intercompany Borrower" means, if and only if approved in writing by
the Administrative Agent and Required Lenders and only to the extent so
approved, any one or more of Holdings and, except for Coho Shell, one or more
Restricted Subsidiaries of Holdings.

         "Interest Coverage Ratio" means, as of any date of determination, the
ratio of EBITDA to Consolidated Interest Expense for the four fiscal quarters
of Holdings and its Restricted Subsidiaries then most recently ended.

         "Interest Period" means with respect to any Eurodollar Advances, each
period commencing on the date such Advances are made (including, as applicable,
the date such advances were made under the Second Restated Credit Agreement) or
Converted from Advances of another Type or, in the case of each subsequent,
successive Interest Period applicable to a Eurodollar Advance, the last day of
the next preceding Interest Period with respect to such Advance, and ending on
the numerically corresponding day in the first, second or third calendar month
thereafter, as a Borrower may select as provided in Section 2.05 or 2.07
hereof, except that each such Interest Period which commences on the last
Business Day of a calendar month (or on any day for which there is no
numerically corresponding day in the appropriate subsequent calendar month)
shall end on the last Business Day of the appropriate subsequent calendar
month.  Notwithstanding the foregoing:  (a) each Interest Period which would
otherwise end on a day which is not a Business Day shall end on the next
succeeding Business Day or if such succeeding Business Day falls in the next
succeeding calendar month, on the next preceding Business Day; (b) any Interest
Period which would otherwise extend beyond the Maturity Date shall end on the
Maturity Date; (c) no more than four (4) Interest Periods for Eurodollar
Advances shall be in effect at the same time; (d) no Interest Period for any
Eurodollar Advances shall have a duration of less than one (1) month and, if
the Interest Period for any Eurodollar Advances would otherwise be a shorter
period, such Advances shall not be available hereunder, and (e) no Interest
Period may extend beyond a principal repayment date unless, after giving effect
thereto, the aggregate principal amount of the Eurodollar Advances having
Interest Periods that end after such principal repayment date shall be equal to
or less than the maximum principal amount of Advances permitted to be
outstanding hereunder after such principal repayment date.

         "Interest Rate Hedging Arrangements" means interest rate swaps,
interest rate caps, interest rate collars or other similar mechanisms enabling
a Person to fix or limit its interest expense.

         "Internal Revenue Code" means the Internal Revenue Code of 1986, as
amended from time to time.

         "Investment" has the meaning specified in the definition of Restricted
Investments.

         "Lender" has the meaning specified in the preamble hereto.

         "Letters in Lieu of Transfer Orders" means each letter in lieu of
transfer and division orders, in form and substance satisfactory to the
Administrative Agent directing each purchaser





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 13
<PAGE>   20
of Hydrocarbons attributable to the Petroleum and Natural Gas Rights pledged as
Collateral to make payment directly to the Administrative Agent.

         "Letter of Credit" means a standby or commercial letter of credit
issued by the Administrative Agent for the account of a Borrower pursuant to
Section 2.01 (b) or, prior to the Closing Date, pursuant to Section 2.01(b) of
the Original Credit Agreement, Section 2.01(b) of the First Amended Credit
Agreement, Section 2.01(b) of the Second Amended Credit Agreement or Section
2.01(b) of the Third Amended Credit Agreement.

         "Letter of Credit Liabilities" means, at any time, all fixed and
contingent liabilities of the Administrative Agent under outstanding Letters of
Credit.

         "Lien" means any lien, mortgage, security interest, tax lien,
financing statement, pledge, charge, hypothecation, assignment, preference,
priority, or other encumbrance of any kind or nature whatsoever (including,
without limitation, any conditional sale or title retention agreement), whether
arising by contract, operation of law, or otherwise.

         "Loan Documents" means this Agreement, the Notes, the Security
Documents and the other Canada Trust Loan Documents (to the extent not amended
and restated pursuant to the Original Credit Agreement, the First Amended
Credit Agreement, the Second Amended Credit Agreement, the Third Amended Credit
Agreement or this Agreement), the "Loan Documents" as defined in the Original
Credit Agreement (to the extent not amended and restated pursuant to the First
Amended Credit Agreement, the Second Amended Credit Agreement, the Third
Amended Credit Agreement, or this Agreement), the "Loan Documents" as defined
in the First Amended Credit Agreement (to the extent not amended and restated
pursuant to the Second Amended Credit Agreement, the Third Amended Credit
Agreement, or this Agreement), the "Loan Documents" as defined in the Second
Amended Credit Agreement (to the extent not amended and restated pursuant to
the Third Amended Credit Agreement or this Agreement), the "Loan Documents" (as
defined in the Third Amended Credit Agreement, to the extent not amended and
restated pursuant to this Agreement), the Letters of Credit, all applications,
agreements and other documents pursuant to which any Letter of Credit is issued
and all other agreements, instruments and other documentation which may from
time to time be executed by any Credit Party or any third Person in favor of
the Administrative Agent or any Lender in connection with this Agreement as any
of such documentation may be amended or otherwise modified from time to time.

         "Louisiana Oil and Gas Mortgage" means the mortgage dated as of
December 2, 1994, pursuant to which the Production Company, Coho Louisiana
Gathering Company and Coho Fairbanks Gathering Company granted to the
Administrative Agent, for the benefit of the Lenders, a first priority lien on
the ING Subject Interests (as such term is defined in the ING Acquisition
Agreement) located in Louisiana and certain other assets as collateral for the
Obligations, as the same may be amended or otherwise modified from time to
time.

         "Majority Lenders" means at any time while no Advances or Letters of
Credit are outstanding Lenders holding at least fifty-one percent (51%) of the
aggregate amount of the





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 14
<PAGE>   21
Commitments and, at any time while Advances or Letters of Credit are
outstanding, Lenders holding at least fifty-one percent (51%) of the
outstanding aggregate principal amount of the Advances and Letter of Credit
Liabilities.

         "Material Adverse Change" means any change that is material and
adverse in or to (i) the operations, business or condition (financial or
otherwise) of (a) any Borrower and its Subsidiaries taken as a whole, (b) the
Borrowers and their Subsidiaries taken as a whole or (c) Holdings and its
Subsidiaries taken as a whole or (ii) the ability of any Credit Party to
perform its obligations under any Related Transactions Document to which it is
a party.

         "Maturity Date" means 11:00 A.M. Houston time on January 2, 2003;
provided, however, the Lenders in their sole discretion may extend the Maturity
Date for additional one-year periods to by notice to the Borrowers.

         "Maximum Rate" means the maximum rate of nonusurious interest
permitted from day to day by applicable law, including to the extent that Texas
law may ever be applied to the Loan Documents despite the parties election of
New York law to govern the Loan Documents, as to Article 5069-1.04, Vernon's
Texas Civil Statutes (and as the same may be incorporated by reference in other
Texas statutes), but otherwise without limitation, that rate based upon the
"indicated rate ceiling" and calculated after taking into account any and all
relevant fees, payments, and other charges charged, paid or contracted for in
connection with the Loan Documents which are deemed to be interest under
applicable law.

         "Mid Louisiana Pledge Agreement" means the Pledge Agreement dated as
of December 2, 1994, pursuant to which the Production Company pledged the
Capital Stock of Exploration to the Administrative Agent, for the benefit of
the Lenders, as collateral for the Obligations, as amended by that certain
First Amendment to Pledge Agreement dated as of the Renewal Date, and as the
same may be amended or otherwise modified from time to time.

         "Mississippi Oil and Gas Deed of Trust" means the Deed of Trust dated
as of December 2, 1994, pursuant to which the Production Company, Coho
Louisiana Gathering Company and Coho Fairbanks Gathering Company granted to the
Administrative Agent, for the benefit of the Lenders, a first priority lien on
the ING Subject Interests (as such term is defined in the ING Acquisition
Agreement) located in Mississippi and certain other assets as collateral for
the Obligations, as the same may be amended or otherwise modified from time to
time.

         "Monthly Payment Date" means the last Business Day of each calendar
month.

         "Mortgage" means the Deed of Trust, Mortgage, Assignment, Security
Agreement and Financing Statement dated as of August 13, 1990 (effective August
16, 1990), made by CRI for the benefit of Canada Trust encumbering the various
real and personal property described therein located in Mississippi, assigned
to the Administrative Agent for the benefit of the Lenders pursuant to the
Assignment, as amended pursuant to that certain Amendment and Ratification of
Deeds of Trust, Mortgages, Assignments, Security Agreements and Financing
Statements dated June 11, 1992, as supplemented pursuant to that certain First
Supplemental Deed of Trust, Mortgage, Assignment,





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 15
<PAGE>   22
Security Agreement and Financing Statement dated June 9, 1992, as amended by
the Third Renewal, Extension and Modification of Deed of Trust, Mortgage,
Assignment, Security Agreement and Financing Statement dated as of August 27,
1992, as amended by the Fourth Renewal, Extension and Modification of Deed of
Trust, Mortgage, Assignment, Security Agreement and Financing Statement dated
as of June 24, 1994, as amended by the Fifth Modification of Mississippi
Mortgage, and as the same may hereafter be amended or otherwise be modified
from time to time.

         "Mortgaged Property" means collectively the Petroleum and Natural Gas
Rights encumbered by the Mortgage, the Deed of Trust, the Louisiana Oil and Gas
Mortgage, the Mississippi Deed of Trust, and the Oklahoma Mortgage, as the same
have been or may be in the future amended or otherwise modified from time to
time.

         "Multiemployer Plan" means a "multiemployer plan" as defined in
Section 4001(a)(3) of ERISA.

         "Note" means a promissory note executed by the Borrowers in the form
of Exhibit A payable to the order of a Lender in the amount of its Commitment
and all extensions, renewals and other modifications thereof and all
substitutions therefor.

         "Obligations" means collectively, (a) the obligation of any Credit
Party to pay, as and when due and payable (by scheduled maturity or otherwise),
all amounts from time to time owing by it to the Administrative Agent, any
Co-Agent, or any Lender, in respect of any Loan Document, whether for
principal, interest, fees or otherwise, (b) the obligation of any Credit Party
to perform or observe all of its other obligations from time to time existing
under any Loan Document and (c) all obligations, indebtedness and liabilities
of any Credit Party to any Lender arising in connection with any Hedging
Arrangements or any Interest Rate Hedging Arrangements.

         "Oklahoma Mortgage" means that certain Mortgage, Assignment of
Production, Security Agreement and Financing Statement dated of even date
herewith pursuant to which Acquisitions is granting to the Administrative
Agent, for the benefit of the Lenders, a first priority Lien on the Amoco
Properties, as the same may be amended from time to time.

         "Original Closing Date" means August 27, 1992.

         "Original Credit Agreement" has the meaning specified in the Recitals
hereto.

         "Original Security Agreement" means that certain Amended and Restated
General Security Agreement and Pledge of Collateral Mortgage Note dated August
27, 1992 between CRI and the Administrative Agent, as modified pursuant to that
certain Act of Partial Release of Act of Collateral Mortgage and Security
Agreement dated June 15, 1993 and pursuant to that certain Partial Release of
Amended and Restated General Security Agreement and Pledge of Collateral
Mortgage Note dated August 17, 1993 and as the same may hereafter be amended or
otherwise modified from time to time.

         "Other Taxes"  has the meaning specified in Section 3.06(a).





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 16
<PAGE>   23
         "Outstanding Credit"  means, at the date of determination, the sum of
the following:  (a) the sum of the aggregate outstanding principal amount of
Advances as of such date, plus (b) the outstanding Letter of Credit Liabilities
as of such date, plus (c) all fixed and contingent liabilities outstanding as
of such date in respect of the letters of credit issued pursuant to the
provisions set forth in subsection 7.02(b)(xi) and, prior to the Closing Date,
pursuant to the provisions set forth in subsection 7.02(b)(xi) of the First
Amended Credit Agreement, Subsection 7.02(b)(xi) of the Second Amended Credit
Agreement and Subsection 7.02(b)(xi) of the Third Amended Credit Agreement,,
and prior to February 8, 1994, pursuant to the provisions of subsection
7.02(b)(ix) of the Original Credit Agreement.

         "Paribas" has the meaning specified in the Recitals hereto.

         "Permitted Coho Shell Advance" means an advance made by a Borrower to
Coho Shell if (A) no Potential Default or Event of Default exists or would
result therefrom, (B) the amount of such advance does not exceed the
Availability existing immediately prior to the time such advance is made, (C)
such advance is used by Coho Shell to acquire Petroleum and Natural Gas Rights,
(D) such advance is otherwise made on terms and conditions and is evidenced and
governed by loan and security documents which are reasonably acceptable to the
Administrative Agent and Lenders, (E) such advance, along with the collateral
securing the repayment thereof and all documentation executed in connection
therewith, is pledged to the Administrative Agent for the benefit of the
Lenders to secure repayment of the Obligations pursuant to the terms of the
Additional Security Agreement, and (F) the applicable Borrower shall have
provided evidence to the Administrative Agent and the Lenders, in form and
substance reasonably acceptable to the Administrative Agent and the Lenders,
that after giving effect to such advance (1) the present fair saleable value of
such Borrower's assets is in excess of the total amount of such Borrower's
liabilities, contingent or otherwise, (2) such Borrower is paying its debts as
they become due, (3) such Borrower does not believe that it will incur debts or
liabilities beyond its ability to pay such debts and liabilities as they
mature, and (4) such Borrower has sufficient capital to carry on its business
as it has been operated and as it is intended to be operated.

         "Permitted Intercompany Advance" means an advance made by a Borrower
to an Intercompany Borrower if (A) no Potential Default or Event of Default
exists or would result therefrom, (B) the amount of such advance does not
exceed the Availability existing immediately prior to the time such advance is
made, (C) such advance is used by the applicable Intercompany Borrower to
acquire Petroleum and Natural Gas Rights, (D) such advance is otherwise made on
terms and conditions and is evidenced and governed by loan and security
documents which are reasonably acceptable to the Administrative Agent and
Lenders, (E) such advance, along with the collateral securing the repayment
thereof and all documentation executed in connection therewith, is pledged to
the Administrative Agent for the benefit of the Lenders to secure repayment of
the Obligations pursuant to the terms of the Additional Security Agreement, and
(F) the applicable Borrower shall have provided evidence to Administrative
Agent and the Lenders, in form and substance reasonably acceptable to the
Administrative Agent and the Lenders, that after giving effect to such advance
(1) the present fair saleable value of such Borrower's assets is in excess of
the total amount of such Borrower's liabilities, contingent or otherwise, (2)
such Borrower is paying its debts as they become due, (3) such Borrower does
not believe that it will incur debts or liabilities beyond





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 17
<PAGE>   24
its ability to pay such debts and liabilities as they mature, and (4) such
Borrower has sufficient capital to carry on its business as it has been
operated and as it is intended to be operated.

         "Person" means an individual, corporation, partnership, association,
joint-stock company, trust, unincorporated organization, joint venture or
governmental authority or other regulatory body.

         "Petroleum and Natural Gas Right" means a Working Interest, a mineral
interest, a mineral servitude or a Royalty Interest relating to lands
(including, without limitation, submerged lands), whether pursuant to a
petroleum and/or natural gas lease or sublease, royalty agreement, farmout
agreement, joint participation agreement, conveyance, pooling agreement, unit
agreement or other instrument.

         "Plan" means an Employee Plan or Multiemployer Plan.

         "Potential Default" means any condition or event which, after notice
or lapse of time or both, would constitute an Event of Default.

         "Prime Rate" means the variable rate of interest established from time
to time by Citibank, N.A. or any successor in interest to such bank (at its
head office) (or such other bank as may be designated by the Administrative
Agent as provided below), as its prime rate of interest, which rate of interest
may or may not be the lowest or best rate charged by such bank; provided,
however, that, in lieu of Citibank, N.A. or any successor bank to Citibank,
N.A.  for purposes of establishing the Prime Rate, the Administrative Agent
may, at any time and from time to time upon five (5) Business Days' prior
written notice to Borrowers and the Lenders, designate (a) The Bank of New
York, New York, New York (at its head office) or (b) any other bank as may be
reasonably acceptable to Borrowers and the Lenders, as the reference bank for
purposes of establishing the Prime Rate.  Each change in the Prime Rate shall
become effective without prior notice to Borrowers automatically as of the
opening of business on the date of such change in the Prime Rate.

         "Prime Rate Advances" means Advances that bear interest at rates based
upon the Prime Rate.

         "Principal Office" means the principal office of the Administrative
Agent located at Houston, Texas.

         "Production Company" means Coho Louisiana Production Company, a
Delaware corporation.

         "Production Report" means, with respect to any calendar quarter, a
report prepared by the Borrowers and certified by the President or any Vice
President of CRI setting forth the quantity of Hydrocarbons produced from the
Proven Reserves covered by the Security Documents during such quarter.

         "Proven Non-Producing Reserves" means Proven Reserves other than
Proven Producing Reserves.





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 18
<PAGE>   25
         "Proven Producing Reserves" means Proven Reserves which are presently
being produced from completion intervals cased for production in existing
wells.

         "Proven Reserves" means, at any time, those quantities of Hydrocarbons
which, upon analysis of geological and engineering information and economic
conditions in respect of Petroleum and Natural Gas Rights of the Borrowers,
demonstrate with reasonable certainty to be economically recoverable in the
future from known oil and gas reservoirs under then-existing economic and
then-current operating conditions, and then existing prices and costs, and
which have demonstrated the ability to produce by the availability of actual
production information or conclusive formation testing.

         "Pro Rata" means, as to any Lender, its ratable share expressed as a
percentage obtained by multiplying by one hundred (100) the ratio obtained by
either (a) dividing the applicable Commitment of the Lender in question by the
total Commitments of all Lenders (whether or not such Commitments have
terminated and if such Commitments have terminated, then the Commitments shall
be deemed equal to the amount thereof immediately prior to such termination for
the purposes of calculating "Pro Rata") or (b) dividing the aggregate principal
amount of the Advances and/or the Letter of Credit Liabilities outstanding
which were made or participated in by the Lender in question by the aggregate
principal amount of all the Advances and/or Letter of Credit Liabilities
outstanding.

         "Quarterly Payment Date" means the last Business Day of January,
April, July and October of each year.

         "Redetermination Date" means five (5) days after the Borrowers shall
have been given notice that the Borrowing Base has been redetermined pursuant
to Section 2.10 .

         "Reference Lenders" means Paribas and such other Lender or Lenders (if
any) as the Administrative Agent may, in addition to Paribas, designate as
Reference Lenders from time to time in its discretion upon notice to the
Borrowers and Lenders.

         "Registration Rights Agreement" means that certain Registration Rights
and Shareholder Agreement among Holdings, The Morgan Stanley Leveraged Equity
Fund II, LP, and Quinn Oil Company Ltd. executed pursuant to the terms of the
ING Acquisition Agreement.

         "Regulation D" means Regulation D of the Board of Governors of the
Federal Reserve System as from time to time in effect and any successor to all
or a portion thereof establishing reserve requirements.

         "Regulatory Change" means, with respect to any Lender, any change
after the date hereof in United States federal, state, or foreign laws, rules,
treaties, directives, guidelines, regulations or policies (including without
limitation, any policy with respect to preexisting laws, rules, treaties,
regulations, guidelines or directives) or the adoption or making after such
date of any interpretations, directives, or requests applying to a class of
banks including such Lender (or its Applicable Lending Office) of or under any
United States federal or state, or any foreign, laws, rules, treaties,
directives, guidelines, regulations or policies (whether or not having the
force of law) by any Governmental





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 19
<PAGE>   26
Authority charged with the interpretation or administration thereof, including,
without limitation, any change in (a) any law, rule, regulation, policy,
guideline or directive contemplated by the report dated July 1988 entitled
"International Convergence of Capital Measurement and Capital Standards" issued
by the Basle Committee on Banking Regulations and Supervisory Practices and (b)
Japanese Ministry of Finance Act No. 901, dated April 1, 1982, as amended or
otherwise modified from time to time, including the amendment dated December
22, 1988 but excluding reserve requirements under Regulation D.

         "Related Transactions Documents" has the meaning specified in the
Second Amended Credit Agreement.

         "Release" means any release, spill, emission, leaking, pumping,
injection, deposit, disposal, discharge, dispersal, leaching, emanation or
migration in, into or onto the environment (including, without limitation,
ambient air, surface water, ground water, land surface, subsurface strata or
work place) of any Contaminant, at, in, by or related to the facilities of any
Person, including, without limitation, the movement of any Contaminant or other
substance through or in the air, soil, surface water or groundwater, except
that for purposes of this definition only, "Contaminant" shall not include
petroleum or petroleum distillates unless (a) the event constituting a
"Release" for purposes of this definition requires notification pursuant to the
Federal Clean Water Act, as amended from time to time, or notification and/or
filing under Mississippi law or other applicable law or (b) the cost of
Remedial Action with respect to such event would exceed One Hundred Thousand
Dollars ($100,000.00).

         "Remedial Action" means all actions required or voluntarily undertaken
to (a) clean up, remove, treat, or in any other way address any Contaminant in
the environment or work place, (b) prevent a Release or threat of Release, or
minimize any further Release, so it does not migrate or endanger or threaten to
endanger public health or welfare of the environment or work place, or (c)
perform pre-remedial studies and investigations and post-remedial monitoring
and care.

         "Renewal Date" means August 8, 1996.

         "Reportable Event" means any of the events set forth in Section 4043
of ERISA.

         "Required Lenders" means at any time while no Advances or Letters of
Credit are outstanding Lenders holding at least sixty-six and two thirds
percent (66 2/3%) of the aggregate amount of the Commitments and, at any time
while Advances or Letters of Credit are outstanding, Lenders holding at least
sixty-six and two thirds percent (66 2/3%) of the outstanding aggregate
principal amount of the Advances and Letter of Credit Liabilities.

         "Reserve Requirement" means, for any Eurodollar Advance for any
Interest Period therefor, the average maximum rate at which reserves (including
any marginal, supplemental or emergency reserves) are required to be maintained
during such Interest Period under Regulation D by member banks of the Federal
Reserve System in New York City with deposits exceeding one billion Dollars
against "Eurocurrency Liabilities" as such term is used in Regulation D.
Without limiting the effect of the foregoing, the Reserve Requirement shall
reflect any other reserves required to be maintained





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 20
<PAGE>   27
by such member banks by reason of any Regulatory Change against (a) any
category of liabilities which includes deposits by reference to which the
Adjusted Eurodollar Rate is to be determined or (b) any category of extensions
of credit or other assets which include Eurodollar Advances.

         "Restricted Investments" means all investments, made in cash or by
delivery of property, by Holdings and its Restricted Subsidiaries (a) in any
Person, whether by acquisition of stock, indebtedness or other obligation or
security, or by loan, advance or capital contribution, or otherwise, or (b) in
any property (items (a) and (b) herein called "Investments"), except the
following:

              (i)         Investments by Holdings in property to be used in the
ordinary course of its business;

             (ii)         Investments by any Subsidiary of Holdings in property
to be used in the ordinary course of business of such Subsidiary;

            (iii)         Investments by Holdings in current assets arising
from the sale of goods and services in the ordinary course of its business;

             (iv)         Investments by any Subsidiary of Holdings in current
assets arising from the sale of goods and services in the ordinary course of
business of such Subsidiary;

              (v)         Investments in direct obligations of the United
States of America, or any agency thereof, or obligations guaranteed by the
United States of America or any agency thereof;

             (vi)         Investments in certificates of deposit maturing one
year or less from the date of acquisition thereof issued by a Lender or any
other bank or trust company organized under the laws of the United States of
America or any state thereof having capital, surplus and undivided profits
aggregating at least Five Hundred Million Dollars ($500,000,000.00);

            (vii)         Investments in commercial paper if at the time of
acquisition such paper is rated in one of the two highest rating categories of
Standard and Poor's Corporation or Moody's Investors Service;

           (viii)         Investments consisting of operating deposit accounts
with commercial banks;

             (ix)         Investments in the ordinary course of business
relating to the acquisition of Petroleum and Natural Gas Rights and the
exploration and development thereof;

              (x)         Investments made in connection with Hedging
Arrangements or Interest Rate Hedging Arrangements;

             (xi)         Investments made by Holdings in any of its
Subsidiaries with the proceeds of the sale of its equity securities;





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 21
<PAGE>   28
            (xii)         Permitted Coho Shell Advances and Permitted
Intercompany Advances, if any; and

           (xiii)         Investments in ING and the ING Subsidiaries arising
as a direct result of the ING Acquisition.

         "Restricted Payments" means, with respect to any Person (a) cash
dividends or distributions or any other dividends or distributions on, or in
respect of, any class of Capital Stock or other equity interests of such
Person, except for distributions made solely in shares of stock or other equity
interests of the same class, (b) any and all funds, cash or other payments made
in respect of the retirement, redemption, repurchase or other acquisition of
such stock or equity interests, unless such stock or equity interests shall be
redeemed or acquired through the exchange of such stock or equity interests
with stock or equity interests of the same class, and (c) any loan or advance
by such Person to, or other investment by such Person in, the holder of any
such stock or equity interests (other than Permitted Coho Shell Advances and
Permitted Intercompany Advances); provided, however, that dividends or other
distributions by any Borrower or any of Holdings' other Restricted Subsidiaries
to its shareholders shall not be considered Restricted Payments if (i) no
Potential Default or Event of Default exists or would result therefrom, (ii)
such dividends or other distributions made in any fiscal year do not exceed an
amount equal to, and are made for the purpose of paying, Holdings'
administrative expenses and taxes incurred and attributable to the operations
of the Borrowers and other Subsidiaries of Holdings for such fiscal year, (iii)
the amount of such expenses and taxes are determined pursuant to agreements in
form and substance reasonably acceptable to the Administrative Agent and
Lenders, and (iv) the amount of such dividends and distributions made for the
purpose of paying such administrative expenses do not exceed Three Million
Dollars ($3,000,000.00) in any fiscal year.

         "Restricted Subsidiary" means Borrowers, Coho Shell and any other
Subsidiary of Holdings or a Borrower, as applicable, that is not an
Unrestricted Subsidiary.

         "Revolving Advance" means an advance of funds by the Lenders or any of
them to a Borrower pursuant to Section 2.01(a) of this Agreement or, prior to
the Closing Date, pursuant to Article II of the Third Amended Credit Agreement.

         "Royalty Interest" means a right to a portion of the production of
Hydrocarbons from lands or a portion of the proceeds from the production of
Hydrocarbons from lands, free and clear of operating or other costs, or a right
to a share of profits from the production of Hydrocarbons from lands, provided
that a Royalty Interest shall not include a Working Interest.

         "Second Amended and Restated Contribution Agreement" means the Second
Amended and Restated Contribution Agreement of dated even date herewith among
Coho Resources, Inc., Coho Energy, Inc., Coho Louisiana Production Company,
Coho Exploration, Inc., Coho Acquisitions Company, Interstate Natural Gas
Company, Coho Fairbanks Gathering Company, and Coho Louisiana Gathering
Company.

         "Second Amended Credit Agreement" has the meaning specified in the
Recitals hereto.





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 22
<PAGE>   29


         "Second Amendment to Pledge Agreement" means that certain Second
Amendment to Pledge Agreement dated of even date herewith between Coho
Resources, Inc. and the Administrative Agent  pursuant to which the CRI Pledge
Agreement is amended to provide for Coho Resources, Inc. pledge of all of the
issued and outstanding capital stock of Acquisitions to the Administrative
Agent for the benefit of the Lenders.

         "Security Documents" means the Mortgage, the Deed of Trust, the
Original Security Agreement, the Additional Security Agreement, the Guaranty,
the Holdings Pledge Agreement, the CRI Pledge Agreement, the ING Pledge
Agreement, the Mid Louisiana Pledge Agreement, the Louisiana Oil and Gas
Mortgage, the Mississippi Oil and Gas Deed of Trust, the Oklahoma Mortgage, the
Negative Pledge Agreement dated February 8, 1994, executed by Coho Canada for
the benefit of the Administrative Agent and the Lenders, Uniform Commercial
Code Financing Statements and such other mortgages, deeds of trust, security
agreements, financing statement and other documentation executed and delivered
by any Credit Party or any other Person for the benefit of the Administrative
Agent and the Lenders that grant or perfect Liens on property to secure the
Obligations or any part thereof, as any of the same may be amended or otherwise
modified from time to time.

         "Second Modification - Brookhaven Deed of Trust" means that certain
Second Renewal, Extension and Modification of Deed of Trust, Mortgage,
Assignment of Production, Security Agreement and Financing Statement dated as
of the Renewal Date by and between CRI and the Administrative Agent.

         "Second Modification to Louisiana Oil and Gas Mortgage" means that
certain Second Renewal, Extension and Modification of Mortgage, Assignment of
Production, Security Agreement and Financing Statement dated as of the Renewal
Date between CRI and the Administrative Agent.

         "Second Modification to Mississippi Oil and Gas Deed of Trust" means
that certain Second Renewal, Extension and Modification of Deed of Trust,
Mortgage, Assignment of Production, Security Agreement and Financing Statement
dated as of the Renewal Date by and between CRI and the Administrative Agent.

         "Seventh Modification of Mississippi Mortgage" means that certain
Seventh Renewal, Extension and Modification of Deed of Trust, Mortgage,
Assignment, Security Agreement and Financing Statement dated as of the Renewal
Date, by and among CRI, Exploration and the Administrative Agent.

         "Sixth Modification of Texas Deed of Trust" means that certain Sixth
Renewal, Extension and Modification of Deed of Trust, Mortgage, Assignment,
Security Agreement and Financing Statement dated as of the Renewal Date, by and
between CRI and the Administrative Agent.

         "Stockholders' Equity" means, with respect to any Person, the
aggregate of the following accounts (or their equivalents) set forth on a
consolidated balance sheet of such Person and its





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 23
<PAGE>   30
Restricted Subsidiaries prepared in accordance with GAAP, provided that there
shall be no adjustments for any write down of any property, plant and equipment
and there shall be excluded therefrom any loans or advances by such Person to
any of its shareholders: (a) the par or stated value of all outstanding Capital
Stock after deducting treasury stock), (b) capital surplus and (c) retained
earnings.

         "Subordinated Indebtedness" means any Indebtedness of any Company or
any Guarantor (whether outstanding on the effective date hereof or hereafter
incurred) incurred pursuant to the Indenture or evidenced by the Securities (as
defined in the Indenture) or the Subsidiary Guaranties (as defined in the
Indenture).

         "Subsidiary" means, as to any Person, any corporation of which more
than 50% of the outstanding Capital Stock having (in the absence of
contingencies) ordinary voting power to elect directors (or Persons performing
similar functions) of such corporation is, at the time of determination, owned
directly, or indirectly through one or more intermediaries, by such Person.

         "Subsidiary Guaranties" means the Guaranty Agreements dated as of
December 2, 1994, executed by ING and each of the ING Subsidiaries in favor of
the Administrative Agent and the Lenders, pursuant to which ING and each ING
Subsidiary unconditionally guaranteed the payment and performance of the
Obligations to the extent as set forth therein, as the same may be amended or
otherwise modified from time to time.

         "Supermajority Lenders" means at any time while no Advances or Letters
of Credit are outstanding, Lenders holding at least seventy-five percent (75%)
of the  aggregate amount of the Commitments and, at any time while Advances or
Letters of Credit are outstanding, Lenders holding at least seventy-five
percent (75%) of the outstanding aggregate principal amount of the Advances and
Letter of Credit Liabilities; provided, however, that a group of Lenders which
excludes more than one Lender shall never be deemed to constitute Supermajority
Lenders.

         "Taxes" has the meaning specified in Section 3.06.

         "Termination Event" means (a) a Reportable Event described in Section
4043 of ERISA (other than a Reportable Event not subject to the provision for
30-day notice to the Pension Benefit Guaranty Corporation under the regulations
promulgated under such Section) with  respect to any Employee Plan, (b) the
withdrawal of Holdings or any of its Affiliates from an Employee Plan during a
plan year in which it was a "substantial employer" as defined in Section
4001(a)(2) of ERISA, if as a result Holdings or such Affiliate would be liable
to the Pension Benefit Guaranty Corporation under ERISA Section 4063(b) for
more than Five Hundred Thousand Dollars ($500,000.00), (c) the filing of a
notice of intent to terminate an Employee Plan (other than in a "standard
termination" under Section 4041 of ERISA) or the treatment of an Employee Plan
amendment as a termination under section 4041 of ERISA,  but only if the
actuarial present value of the benefit liabilities under the Employee Plan
exceeds the current value of assets allocable to those benefit liabilities in
that Employee Plan by more than Five Hundred Thousand Dollars





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 24
<PAGE>   31
($500,000.00), (d) the institution of proceedings by the Pension Benefit
Guaranty Corporation to terminate an Employee Plan, or (e) any other event or
condition which constitutes grounds under Section 4042 of ERISA for the
termination of, or the appointment of a trustee to administer, any Employee
Plan.

         "Type" means any type of Advance determined with respect to the
interest option applicable thereto, i.e. a Prime Rate Advance or a Eurodollar
Advance.

         "Unrestricted Subsidiary" means (i) any Subsidiary of Holdings (other
than Coho Shell or any Credit Party) that Holdings has designated in writing to
the Administrative Agent and the Lenders as an Unrestricted Subsidiary and each
Subsidiary of such designated Subsidiary (other than Coho Shell or any Credit
Party), and (ii) the following Subsidiaries of Coho Canada:  253741 Alberta
Ltd., an Alberta, Canada corporation and 249183 Alberta Ltd., an Alberta,
Canada corporation.  Once a Subsidiary has been designated as an Unrestricted
Subsidiary it may not become a Restricted Subsidiary without the consent of all
the Lenders.

         "Working Interest" means an interest embodying the right to operate a
well or wells and the right to share in production of Hydrocarbons from such
well or wells or a right to a share of the revenues from the sale of such
Hydrocarbons.

         SECTION 1.02.  Accounting and other Terms.  Unless otherwise expressly
stated herein, all accounting terms used in this Agreement which are not
otherwise defined herein shall be construed in accordance with GAAP.  All terms
used in this Agreement which are defined in Article 9 of the Uniform Commercial
Code (the "UCC") in effect in the State of Texas on the date hereof and which
are not otherwise defined herein shall have the same meanings herein as set
forth therein.  The words "hereof", "herein", and "hereunder" and words of
similar import referring to this Agreement refer to this Agreement as a whole
and not to any particular provision of this Agreement.  Unless otherwise
specified, all Article and Section references pertain to this Agreement.

                                   ARTICLE II

                         ADVANCES AND LETTERS OF CREDIT

         SECTION 2.01.  Commitments.

         (a)     Revolving Advances.  Subject to the terms and conditions of
this Agreement, each Lender severally agrees to make one or more Revolving
Advances to the Borrowers from time to time from the Closing Date prior to the
Maturity Date in an aggregate principal amount at any time outstanding up to
but not exceeding the amount of such Lender's Commitment as then in effect;
provided, however, that the Outstanding Credit shall not any time exceed the
Borrowing Base.  Subject to the foregoing limitations, and the other terms and
provisions of this Agreement, Borrowers may borrow, repay, and reborrow
hereunder the amount of the Commitments by means of Prime Rate Advances and
Eurodollar Advances prior to the Maturity Date, Borrowers may Convert Revolving
Advances of one Type into Revolving Advances of another Type.  Revolving





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 25
<PAGE>   32
Advances of each Type made by each Lender shall be made and maintained at such
Lender's Applicable Lending Office for Advances of such Type.

         (b)     Letters of Credit.

              (i)         Issuance. Subject to the terms and conditions of this
Agreement, the Administrative Agent agrees to issue one or more Letters of
Credit for the account of any Borrower from time to time from the Closing Date
hereof to but excluding the Maturity Date; provided, however, that (A) the
outstanding Letter of Credit Liabilities shall not at any time exceed Fifteen
Million Dollars ($15,000,000.00) and (B) the Outstanding Credit shall not any
time exceed the Borrowing Base .  Each Letter of Credit shall be issued in the
minimum face amount of One Hundred Thousand Dollars ($100,000.00), shall not
have an expiration date beyond the Maturity Date, shall be payable in Dollars,
must support a transaction that is entered into in the ordinary course of
business by a Borrower or any Subsidiary of a Borrower, must otherwise be
satisfactory in form and substance to the Administrative Agent and shall be
issued pursuant to such documents and instruments (including without
limitation, letter of credit applications and agreements) as the Administrative
Agent may require.  At the time of issuance of each Letter of Credit, the
Administrative Agent shall be deemed, without further action by any party
hereto, to have sold to each other Lender, and each other Lender shall be
deemed without further action by any party hereto, to have purchased from the
Administrative Agent, a participation to the extent of such Lender's Pro Rata
portion (calculated on the basis of the Commitments) of such Letter of Credit
and the related Letter of Credit Liabilities.

             (ii)         Reimbursement of Letter of Credit Drawings.  Upon
receipt by the Administrative Agent of a request for any drawing under a Letter
of Credit, the Administrative Agent shall promptly notify the Borrower which is
the account party on the Letter of Credit and each Lender as to the payment
date for such drawing and amount to be paid as a result of the drawing.  Each
Lender shall make available to the Administrative Agent its Pro Rata portion
(calculated on the basis of the Commitments) of the amount to be paid as result
of the drawing on the Letter of Credit, at the Principal Office, in immediately
available funds, not later than 11:00 A.M. (Houston, Texas time) on the payment
date.  Each payment made by the Administrative Agent pursuant to a drawing
under a Letter of Credit shall be deemed an Advance under each Lender's Note in
an amount equal to such Lender's Pro Rata portion of such payment (calculated
on the basis of the Commitments).  Each such Advance shall be a Prime Rate
Advance.

            (iii)         Letter of Credit Fees. The Borrowers jointly and
severally agree to pay the Administrative Agent for the benefit of each Lender
a letter of credit fee on such Lender's Pro Rata portion (calculated on the
basis of the Commitments) of the average daily amount available for drawing
under the Letters of Credit, such letter of credit fee to be paid in arrears on
each Quarterly Payment Date and on the Maturity Date and to be calculated at a
rate of one percent (1%) per annum of such average daily amount available for
drawing under the Letters of Credit based on a 365 or 366 day year (as the case
may be) and the actual number of days elapsed.  After receiving any payment of
any letter of credit fees under this clause (iii), the Administrative Agent
will promptly pay to each Lender the letter of credit fees then due such
Lender.  With respect to





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 26
<PAGE>   33
each Letter of Credit, the Borrowers will also jointly and severally pay to the
Administrative Agent for its account only and on the date of the issuance of
the Letter of Credit an issuance fee equal to one fourth of one percent (0.25%)
of the maximum amount available to be drawn under the Letter of Credit.

         SECTION 2.02.  Notes.  The obligation of the Borrowers to repay each
Lender for Advances made by such Lender and interest thereon shall be evidenced
by a Note executed by the Borrowers, payable to the order of such Lender, in
the principal amount of such Lender's Commitment as originally in effect.  The
Lenders and the Borrowers acknowledge and agree that the Lenders are willing to
make advances to any Borrower only if the other Borrowers are liable for
payment thereof and, accordingly, and in order to avoid the necessity of the
issuance of a separate note for each Borrower the payment of which would be
guaranteed by each of the other  Borrowers, each of the Borrowers desires to be
a co-borrower of, and jointly and severally liable for, payment of the
Advances.  None of the Borrowers is a co-borrower with respect to an advance or
is executing a Note as a co-maker thereof as a condition to or otherwise in
connection with any Advance to such Borrower other than an Advance the proceeds
of which are used by such Borrower.

         SECTION 2.03.  Repayment of Advances.  All outstanding Revolving
Advances shall be due and payable in full on the Maturity Date.

         SECTION 2.04.  Interest. The unpaid principal amount of the Advances
shall bear interest prior to maturity at a varying rate per annum equal from
day to day to the lesser of (a) the Maximum Rate, or (b) the Applicable Rate,
each such change in the rate of interest charged on the Advances to become
effective, without notice to Borrowers, on the effective date of each change in
the Applicable Rate or the Maximum Rate, as the case may be; provided, however,
that if at any time the rate of interest specified in clause (b) preceding
shall exceed the Maximum Rate, thereby causing the interest on the Advances to
be limited to the Maximum Rate, then any subsequent reduction in the Applicable
Rate shall not reduce the rate of interest on the Advances below the Maximum
Rate until the aggregate amount of interest accrued on the Advances equals the
aggregate amount of interest which would have accrued on the Advances if the
interest rate specified in clause (b) preceding had at all times been in
effect.  Accrued and unpaid interest on the Advances shall be due and payable
as follows:

                      (i)         in the case of Prime Rate Advances, on each
         Monthly Payment Date and on the Maturity Date applicable to such
         Advances;

                      (ii)        in the case of each Eurodollar Advance, on
         the last day of the Interest Period with respect thereto, but no less
         often than quarterly;

                    (iii)         upon the payment or prepayment of any Advance
         or the Conversion of any Advance to an Advance of another Type (but
         only on the principal amount so paid, prepaid, or Converted); and

                      (iv)        on the Maturity Date.





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 27
<PAGE>   34
         All past due principal and interest shall bear interest at the Default
Rate.

         SECTION 2.05.  Access to Availability.

         (a)     Borrowing Procedure.  Each Borrower requesting an Advance
shall give the Administrative Agent notice by means of an Advance Request Form
of each requested Advance (other than an Advance pursuant to subsection
2.01(b)(ii)), at least two (2) Business Days  before the requested date of each
Prime Rate Advance and at least three (3) Business Days  before the requested
date of each Eurodollar Advance, specifying:  (i) the requested date of such
Advance (which shall be a Business Day), (ii) the amount of such Advance, (iii)
the Type of the Advance, and (iv) in the case of a Eurodollar Advance, the
duration of the Interest Period for such Advance.  The Administrative Agent at
its option may accept telephonic requests for Advances, provided that such
acceptance shall not constitute a waiver of the Administrative Agent's right to
delivery of an Advance Request Form in connection with subsequent Advances.
Any telephonic request for an Advance by a Borrower shall be promptly confirmed
by submission of a properly completed Advance Request Form to the
Administrative Agent.  Each Advance (other than an Advance pursuant to
subsection 2.01(b)(ii)) shall be in a minimum principal amount of One Million
Dollars ($1,000,000.00).  The aggregate principal amount of Eurodollar Advances
having the same Interest Period shall be at least equal to One Million Dollars
($1,000,000.00).  The Administrative Agent shall promptly notify each Lender of
each such notice of borrowing.  Not later than 11:00 A.M. Houston, Texas time
on the date specified for each Advance hereunder, each Lender will make
available to the Administrative Agent at the Principal Office in immediately
available funds, for the account of the applicable Borrower, its Pro Rata share
(determined based on the Commitments) of each Advance.  After the
Administrative Agent's receipt of such funds and subject to the other terms and
conditions of this Agreement, the Administrative Agent will make such Advances
available to the applicable Borrower by depositing the same, in immediately
available funds, in an account of such Borrower designated by such Borrower.
All notices under this subsection (a) given by any Borrower shall be
irrevocable and shall be given not later than 10:00 A.M. Houston, Texas, time
on the day which is not less than the number of Business Days specified above
for such notice.

         (b)     Procedure for Issuing Letters of Credit.  Each Letter of
Credit shall be issued on at least five (5) Business Days prior notice from the
requesting Borrower to the Administrative Agent by means of an Advance Request
Form describing the proposed terms of such Letter of Credit and the
transactions proposed to be supported thereby.  The Administrative Agent at its
option may accept telephonic requests for Letters of Credit, provided that such
acceptance shall not constitute a waiver of the Administrative Agent's right to
require delivery of an Advance Request Form in connection with subsequent
Letters of Credit.  Any telephonic request for a Letter of Credit by a Borrower
shall be promptly confirmed by submission of a properly completed Advance
Request Form to the Administrative Agent.  The Administrative Agent shall
promptly notify each Lender of each request for a Letter of Credit.  Upon
fulfillment of the applicable conditions precedent in Article V, the
Administrative Agent shall make the Letter of Credit available to such
Borrower.  The Administrative Agent shall provide copies of all issued Letters
of Credit to Lenders after issuance thereof.  All notices given by a Borrower
under this subsection (b) shall be irrevocable and shall be given not later
than 10:00 A.M. Houston, Texas time on the day which is not less than the
number of Business Days specified above for such notice.





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 28
<PAGE>   35
         SECTION 2.06.  Use of Proceeds. Upon the effectiveness of this
Agreement, the principal amount then outstanding under the Third Amended Credit
Agreement is and shall be deemed to be a "Revolving Advance" outstanding
hereunder, each Lender to have its Pro Rata share thereof (based on the
Commitments) and such Revolving Advance to be of the Type or Types selected by
CRI pursuant to the Third Amended Credit Agreement.  The proceeds of all other
Revolving Advances shall be used by Borrowers (i) to finance the acquisition of
Petroleum and Natural Gas Rights, including those being acquired pursuant to
the AMOCO Purchase Agreement, (ii) for the exploration for, drilling and
development of Petroleum and Natural Gas Rights, (iii) to make Permitted Coho
Shell Advances and Permitted Intercompany Advances, and (iv) for other general
corporate purposes; provided, however, that the proceeds of Revolving Advances
may not be, and shall not be, used to pay or prepay any Subordinated
Indebtedness, including, without limitation, any Indebtedness evidenced by the
Indenture, the Securities or the Subsidiary Guaranties (as defined in the
Indenture).

         SECTION 2.07.  Conversions and Continuations.  The Borrowers shall
have the right from time to time to Convert all or part of an Advance of one
Type into an Advance of another Type or to Continue Advances of one Type as
Advances of the same Type by giving the Administrative Agent written notice at
least two (2) Business Days before Conversion into a Prime Rate Advance and at
least three (3) Business Days before Conversion into or Continuation of a
Eurodollar Advance, specifying:  (a) the Conversion or Continuation date, (b)
the amount of the Advance to be Converted or Continued, (c) in the case of
Conversions, the Type of Advance to be Converted into, and (d) in the case of a
Continuation of or Conversion into a Eurodollar Advance, the duration of the
Interest Period applicable thereto; provided, however, that (i) Eurodollar
Advances may only be Converted on the last day of the Interest Period, and (ii)
except for Conversions into Prime Rate Advances, no Conversions shall be made
while an Event of Default or Potential Default has occurred and is continuing.
The Administrative Agent shall promptly notify each Lender of each such notice.
All notices given by any Borrower under this Section 2.07 shall be irrevocable
and shall be given not later than 11:00 A.M., Houston, Texas time on the day
which is not less than the number of Business Days specified above for such
notice.  If any Borrower shall fail to give the Administrative Agent the notice
as specified above for Continuation or Conversion of a Eurodollar Advance prior
to the end of the Interest Period with respect thereto, such Eurodollar Advance
shall automatically be Converted into a Prime Rate Advance on the last day of
the Interest Period for such Eurodollar Advance.

         SECTION 2.08.  Commitment Fee; Reduction or Termination of
Commitments.  The Borrowers jointly and severally agree to pay to the
Administrative Agent for the benefit of each Lender a commitment fee on the
average daily Availability, from and including the last Quarterly Payment Date
prior to the Closing Date, to and including the Maturity Date, at the rate of
three-eighths of one percent (.375%) per annum based on a 365 or 366 day year
(as the case may be) and the actual number of days elapsed, payable on each
Quarterly Payment Date prior to the Maturity Date and on the Maturity Date.
The Borrowers shall have the right at any time to terminate in whole or from
time to time to irrevocably reduce in part the Commitments upon at least three
(3) Business Days prior notice to the Administrative Agent specifying the
effective date thereof, whether a termination or reduction is being made, and
the amount of any partial reduction, provided that (a) each partial reduction
shall be in the amount of One Million Dollars ($1,000,000.00) or an integral





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 29
<PAGE>   36
multiple thereof, (b) the Commitments shall not be reduced below an aggregate
amount equal to Ten Million Dollars ($10,000,000.00) unless completely
terminated, (c) the Borrowers shall simultaneously prepay the amount by which
the unpaid principal amount of the Advances exceeds the Commitments (after
giving effect to such notice) plus accrued and unpaid interest on the principal
amount so prepaid and (d) the Borrowers may not reduce the Commitments below an
amount equal to the aggregate unused portion of the stated amount of the
Letters of Credit then outstanding.  The Commitments may not be reinstated
after they have been terminated or reduced.  The Commitments shall
automatically terminate on the Maturity Date except with respect to calculating
the Lenders' Pro Rata portions hereunder.

         SECTION 2.09.  Additional Fees.

         (a)     Revolver Activation Fee.  At the time of any increase in the
Borrowing Base after the Closing Date, the Borrowers shall jointly and
severally pay to the Administrative Agent, for the benefit of each Lender, a
Revolver activation fee equal to three-eighths of one percent (.375%) of the
amount of the increase; provided, however, that the cumulative total of all
Revolver activation fees shall not exceed three-eighths of one percent (.375%)
of $300,000,000.00.

         (b)     Facility Fee.  On the Closing Date, the Borrowers shall
jointly and severally pay to the Administrative Agent, for the benefit of each
Lender, a Facility Fee equal to 0.1875% of the Borrowing Base in effect at the
Closing Date.

         SECTION 2.10.  Borrowing Base.

         (a)     Initial Amount; Waiver of Redetermination.  During the period
from the Closing Date to the first Redetermination Date following the Closing
Date, the Borrowing Base shall be equal to Three Hundred Million Dollars
($300,000,000.00).

         (b)     Semiannual Redeterminations.  Promptly after each January 1st
of each calendar year commencing 1998 and in any event prior to each April 1st,
the Borrowers shall furnish to the Administrative Agent and each of the other
Lenders an Engineering Report certified by the Independent Engineer and the
chief financial officer of CRI and prepared within thirty (30) days of the date
of delivery (such report being hereinafter referred to as the "Annual
Engineering Report").  Within thirty (30) days after receipt by the
Administrative Agent and the other Lenders of such Annual Engineering Report,
the Administrative Agent and the Co-Documentation Agents shall determine a
proposed redetermination of the Borrowing Base in accordance with Section
2.10(f).  The Administrative Agent shall then notify the Lenders of the
proposed redetermined  Borrowing Base, request the approval of the Lenders to
the proposed redetermined Borrowing Base and request any Lender who does not
agree with the proposed redetermined Borrowing Base to propose the Borrowing
Base level acceptable to it.  If Required Lenders or, if a Borrowing Base
increase is proposed, Supermajority Lenders agree to the  proposed redetermined
Borrowing Base, the Administrative Agent shall notify the Borrowers of the
redetermined Borrowing Base.  If Required Lenders (or, if a Borrowing Base
increase is requested, Supermajority Lenders) do not agree with the proposed
redetermined Borrowing Base, the Administrative Agent shall determine the
Borrowing Base level approved by Required Lenders (or, if a Borrowing Base
increase is requested,





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 30
<PAGE>   37
Supermajority Lenders), and the Administrative Agent shall promptly notify the
Borrowers of the amount of the Borrowing Base as so redetermined.  Promptly
after each July 1st of each calendar year commencing July 1, 1998 and in any
event prior to each October 1st, Borrower shall furnish to the Administrative
Agent and each of the other Lenders an Engineering Report certified by the
chief financial officer of CRI and prepared within thirty (30) days of the date
of delivery (such report being hereinafter referred to as the "Semi-Annual
Engineering Report").  Within thirty (30) days after receipt by the
Administrative Agent and the other Lenders of such Semi-Annual Engineering
Report and provided that the Administrative Agent reasonably determines that
such Semi-Annual Engineering Report is satisfactory in all respects, the
Administrative Agent and the Co-Documentation Agents shall determine a proposed
redetermination of the Borrowing Base in accordance with Section 2.10(f).  The
Administrative Agent and the Co-Documentation Agents shall then notify the
Lenders of the proposed redetermined Borrowing Base, request the approval of
the Lenders to the proposed redetermined Borrowing Base and request any Lender
who does not agree with the proposed redetermined Borrowing Base to propose the
Borrowing Base level acceptable to it.  If Required Lenders or (if a Borrowing
Base increase is proposed, Supermajority Lenders) agree to the  proposed
redetermined Borrowing Base, the Administrative Agent shall notify the
Borrowers of the redetermined Borrowing Base.  If Required Lenders (or, if a
Borrowing Base increase is requested, Supermajority Lenders) do not agree with
the proposed redetermined Borrowing Base, the Administrative Agent shall
determine the Borrowing Base level approved by Required Lenders (or, if a
Borrowing Base increase is requested, Supermajority Lenders), and shall
promptly notify the Borrowers of the amount of the Borrowing Base as so
redetermined.  If the Administrative Agent reasonably determines that such
Semi-Annual Engineering Report is not satisfactory, Borrowers shall furnish to
the Administrative Agent and each of the other Lenders, within thirty (30) days
after notification from the Administrative Agent that such Semi-Annual
Engineering Report is not satisfactory, another Semi-Annual Engineering Report
certified by an Independent Engineer and the chief financial officer of CRI and
prepared within thirty (30) days of the date of delivery.  Within thirty (30)
days after receipt by the Administrative Agent and the other Lenders of such
re-submitted Semi-Annual Engineering Report, the Administrative Agent, the
Co-Documentation Agents and the Required Lenders shall make a redetermination
of the Borrowing Base as described above in accordance with Section 2.10(f) and
the Administrative Agent shall promptly notify the Borrowers of the amount of
the Borrowing Base as so redetermined.

         (c)     Interim Redetermination by Lenders.  The Required Lenders (or,
if a Borrowing Base increase is requested, Supermajority Lenders) may
redetermine the Borrowing Base more often than semiannually in their sole
discretion and based on such information as they may deem relevant (but in
accordance with Section 2.10(f)); provided, however, that  (i) the Borrowing
Base will not be redetermined by the Required Lenders more than once during any
period between the semiannual redetermination dates established in Section
2.10(b) and (ii) the Borrowing Base cannot be redetermined under this Section
2.10(c) more than seven (7) times prior to the Revolving Maturity Date.  If the
Administrative Agent, the Co-Documentation Agents and the Required Lenders
redetermine the Borrowing Base, the Administrative Agent shall promptly provide
the Borrowers with notice of the redetermination and of the amount of the
Borrowing Base as so redetermined.

         (d)     Interim Redeterminations at the Request of Borrowers.  The
Borrowers may request a redetermination of the Borrowing Base more often than
semiannually in order to add to the





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 31
<PAGE>   38
Borrowing Base the value of additional Proven Reserves which have been or will
be acquired by a Borrower or for any other reason; provided, however, that the
Borrowing Base will not be redetermined at the request of the Borrowers more
than once during any period between the semiannual Redetermination Dates
established in Section 2.10(b).  In order for the Lenders to consider a
redetermination of the Borrowing Base pursuant to this Section 2.10(d), the
Borrowers must submit a written request for redetermination to the
Administrative Agent containing (i) a statement as to the reason for such
request; (ii) if additional Proven Reserves are to be included in the
redetermination, an Engineering Report relating to such Proven Reserves dated a
current date and reasonably satisfactory to the Lenders and otherwise in form
and substance reasonably acceptable to the Lenders and (iii) such other
information as the Lenders may reasonably request.  Within thirty (30) days of
receipt of all information requested by the Lenders in connection with a
request under this Section 2.10(d), the Administrative Agent, the
Co-Documentation Agents and the Required Lenders (or, if a Borrowing Base
increase is requested, Supermajority Lenders) shall redetermine the Borrowing
Base in accordance with Section 2.10(f) and as described above and the
Administrative Agent shall promptly notify the Borrowers of the amount of the
Borrowing Base as so redetermined.

         (e)     Redetermination as a Result of a Sale of Collateral or
Issuance of Other Indebtedness.  In addition to the redeterminations described
above in this Section 2.10, the Borrowing Base shall be redetermined by the
Administrative Agent, the Co-Documentation Agents and the Required Lenders in
accordance with Section 2.10(f) each date (i) that a Borrower disposes of any
assets which comprise part of the Borrowing Base (whether or not such assets
are part of the Collateral) in accordance with Section 7.02(d) to subtract from
the Borrowing Base the value of such assets, if any, disposed of by such
Borrower (unless a Borrowing Base redetermination indicates a decrease is not
required), and (ii) that any other indebtedness of the a Borrower is issued as
may be permitted by Section 7.02(b)(vii).  The Administrative Agent shall
promptly notify the Borrowers of the amount of the Borrowing Base as so
redetermined.

         (f)     Standards for Redetermination.  Each redetermination of the
Borrowing Base made by the Required Lenders or Supermajority Lenders, as
applicable, pursuant to this Section 2.10 shall be made (i) in the sole
discretion of the Required Lenders or Supermajority Lenders, as applicable (but
in accordance with the other provision of this Section 2.10(f)), (ii) in
accordance with the Required Lenders' or Supermajority Lenders' customary
internal standards and practices for valuing and redetermining the value of oil
and gas properties in connection with reserve based oil and gas loan
transactions, (iii) in good faith, (iv) in conjunction with the most recent
Engineering Reports or other information received by the Lenders relating to
the Proven Reserves of the Borrowers and (v) based upon the estimated value of
the Petroleum and Natural Gas Rights (including both Proven Producing Reserves
and Proven Non-Producing Reserves) owned or to be acquired concurrently by the
Borrowers; provided, however, that, in valuing Proven Reserves of the Borrowers
for purposes of redetermining the Borrowing Base, the Administrative Agent and
the Required Lenders or Supermajority Lenders, as applicable, agree to use
customary industry pricing assumptions; provided further, however, no Proven
Reserves shall be considered for inclusion in the Borrowing Base unless (1)
such Proven Reserves are (or will become simultaneously with an Advance
hereunder) Collateral; and (2) unless otherwise agreed, the Administrative
Agent shall have received a reasonably satisfactory title opinion or other
evidence reasonably satisfactory to the Required Lenders that the
Administrative Agent has a valid, first priority Lien on the Petroleum and
Natural Gas Rights





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 32
<PAGE>   39
relating thereto.  At all times after the Borrowers have been given
notification of a redetermination of the Borrowing Base, the Borrowing Base
shall be equal to the amount thereof as so subsequently redetermined until the
Borrowing Base is redetermined in accordance with this Section 2.10.

                                  ARTICLE III

                                    PAYMENTS

         SECTION 3.01.  Method of Payment.  All payments of principal,
interest, and other amounts to be made by Borrowers under this Agreement, the
Notes, or any other Loan Document shall be made to the Administrative Agent at
its Principal Office for the account of each Lender's Applicable Lending Office
in Dollars and in immediately available funds, without set-off, deduction, or
counterclaim, not later than 11:00 A.M., Houston, Texas time on the date on
which such payment shall become due (each such payment made after such time on
such due date to be deemed to have been made on the next succeeding Business
Day).  Borrowers shall, at the time of making each such payment, specify to the
Administrative Agent the sums payable by Borrowers under this Agreement, the
Notes, or any other Loan Document to which such payment is to be applied (and
in the event that Borrowers fail to so specify, or if an Event of Default has
occurred and is continuing, the Administrative Agent may apply such payment to
the Obligations in such order and manner as it may elect in its sole
discretion, subject to Section 3.02 with regard to prepayments, and Section
3.03 hereof).  Each payment received by the Administrative Agent under this
Agreement, the Notes, or any other Loan Document for the account of a Lender
shall be paid promptly to such Lender, in immediately available funds, for the
account of such Lender's Applicable Lending Office on the same Business Day of
Administrative Agent's receipt thereof if received before 11:00 A.M. Houston,
Texas time on a Business Day or the next Business Day if received after 11:00
A.M. Houston, Texas time on a Business Day.  Whenever any payment under this
Agreement, the Notes, or any other Loan Document shall be stated to be due on a
day that is not a Business Day, such payment may be made on the next succeeding
Business Day, and such extension of time shall in such case be included in the
computation of the payment of interest and commitment fee, as the case may be.

         SECTION 3.02.  Repayments and Prepayment.

         (a)     Optional Repayments and Prepayments.  Borrowers may, upon at
least two (2) Business Days prior notice to the Administrative Agent in the
case of Prime Rate Advances and at least three (3) Business Days prior notice
to the Administrative Agent in the case of Eurodollar Advances, repay or prepay
the Notes in whole at any time or from time to time in part without premium or
penalty but with accrued and unpaid interest to the date of repayment or
prepayment on the amount so repaid or prepaid; provided that (i) Eurodollar
Advances may be repaid or prepaid only on the last day of the Interest Period
for such Advances, unless the Borrowers shall pay to the Administrative Agent
for the account of the applicable Lenders any amounts owed pursuant to Section
4.05 and (ii) each partial repayment or prepayment shall be in the principal
amount of One Million Dollars ($1,000,000.00) or an integral multiple thereof.

         (b)     Mandatory Prepayments.  If the Outstanding Credit at any time
ever exceeds the Borrowing Base, the Borrowers shall within thirty (30) days
after notification from the





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 33
<PAGE>   40
Administrative Agent, either (a) provide collateral with value and quantity in
amounts satisfactory to Majority Lenders in their sole discretion equal to such
excess, (b) prepay, without premium or penalty (except for any applicable
breakage costs), the principal amount of the Obligations in an amount equal to
such excess plus accrued interest or (c) prepay the principal amount of the
Obligations in an amount equal to such excess in five (5) equal monthly
installments provided that the entire amount of such mandatory prepayment shall
be paid on or prior to the immediately succeeding Redetermination Date.  Any
prepayments under this Section 3.02(b) shall be distributed to the Lenders
pursuant to Section 3.03 until or unless all amounts under the applicable Notes
have been paid, then such repayments shall be held by the Administrative Agent
as additional collateral pursuant to such documentation and agreements as
Administrative Agent may require to secure the Obligations with respect to the
applicable Letter of Credit Liabilities outstanding, if any. Upon any sale or
sales of Collateral in any calendar year with aggregate net after-tax proceeds
in excess of $5,000,000, the Borrowers shall make the prepayments required
under Section 7.02(d)(iii)(1).

         SECTION 3.03.  Pro Rata Treatment; Distribution of Payments.

         (a)     Treatment.  Except to the extent otherwise provided herein:
(i) each Advance shall be made by the Lenders under Section 2.01 and each
payment of commitment fee under Section 2.08 shall be made for the account of
the Lenders and each termination or reduction of the Commitments under Section
2.08 shall be applied to the Commitments of the Lenders, Pro Rata according to
the respective unused Commitments; (ii) each Conversion of Advances of a
particular Type (other than Conversions provided for by Section 4.04), shall be
made Pro Rata among the Lenders holding Advances of such Type according to the
respective principal amounts of such Advances held by such Lenders; (iii) each
payment and prepayment of principal of or interest on Advances by Borrowers of
a particular Type shall be made to the Administrative Agent for the account of
the Lenders holding Advances of such Type Pro Rata in accordance with the
respective unpaid principal amounts of such Advances held by such Lenders; (iv)
Interest Periods for Advances of a particular Type shall be allocated among the
Lenders holding Advances of such Type Pro Rata according to the respective
principal amounts held by such Lenders; (v) all proceeds received by the
Administrative Agent on account of the Collateral or from the exercise of any
rights or remedies under the Loan Documents shall be shared by the Lenders,
each Lender to receive its Pro Rata portion thereof determined based on the
outstanding principal amount of the Advances owed to the Lenders; provided,
however, that from any such proceeds, the Administrative Agent shall first be
entitled to deduct all unpaid or unreimbursed Obligations owing to the
Administrative Agent under the terms of the Loan Documents in its capacity as
Administrative Agent only and not in its capacity as a Lender.

         (b)     Distribution of Payments.  The Administrative Agent shall
distribute the amount of each payment or prepayment of principal of or interest
on Advances by Borrowers (other than from proceeds of Collateral or proceeds
from the exercise of rights or remedies) to the Lenders, each Lender to receive
the Pro Rata portion thereof to which it is entitled as calculated pursuant to
clause (a) of this Section 3.03 on the same Business Day of the Administrative
Agent's receipt thereof if received before 11:00 A.M. Houston, Texas time on a
Business Day or the next Business Day if received after 11:00 A.M. Houston,
Texas time on a Business Day.  Upon receipt by the Administrative Agent of any
proceeds of Collateral or proceeds received from the exercise of rights or
remedies, the Administrative Agent shall reimburse itself for any unpaid or
unreimbursed





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 34
<PAGE>   41
Obligations owing to the Administrative Agent under the Loan Documents in its
capacity as Administrative Agent only and not in its capacity as a Lender and
then shall distribute the remaining amount to the Lenders, each Lender to
receive the Pro Rata portion thereof to which it is entitled as calculated
pursuant to clause (a) of this Section 3.03; provided however, if the Letter of
Credit Liabilities remain outstanding and all other Obligations have been
satisfied, the Administrative Agent may hold any such proceeds as collateral
pursuant to such documentation as the Administrative Agent may require to
secure the Obligations with respect to the applicable Letter of Credit
Liabilities outstanding.  Subject to the forgoing, any and all other amounts
received by the Administrative Agent as payment on the Obligations, shall be
distributed to the Lenders on the same Business Day of the Administrative
Agent's receipt thereof if received before 11:00 A.M. Houston, Texas time on a
Business Day or the next Business Day if received after 11:00 A.M. Houston,
Texas time on a Business Day, each Lender to receive its Pro Rata portion
thereof in immediately available funds (calculated on the basis of the
outstanding principal amount of the Advances or, if no principal is
outstanding, on the basis of the Commitments) unless this Agreement or any
other Loan Document directs that the Administrative Agent distribute such
amounts in an alternative manner.

         SECTION 3.04.  Non-Receipt of Funds by the Administrative Agent.
Unless the Administrative Agent shall have been notified by a Lender or a
Borrower  (the "Payor") prior to the date on which such Lender is to make
payment to the Administrative Agent of the proceeds of an Advance to be made by
it hereunder or a Borrower is to make a payment to the Administrative Agent for
the account of one or more of the Lenders, as the case may be (such payment
being herein called the "Required Payment") (which notice shall be effective
upon receipt) that the Payor does not intend to make the Required Payment to
the Administrative Agent, the Administrative Agent may assume that the Required
Payment has been made and may, in reliance upon such assumption (but shall not
be required to), make the amount thereof available to the intended recipient on
such date and, if the Payor has not in fact made the Required Payment to the
Administrative Agent, the recipient of such payment shall, on demand, pay to
the Administrative Agent the amount made available to it together with interest
thereon in respect of the period commencing on the date such amount was so made
available by the Administrative Agent until the date the Administrative Agent
recovers such amount at a rate per annum equal to the Federal Funds Rate for
such period.

         SECTION 3.05.  Computation of Interest.  Interest on the indebtedness
evidenced by the Notes shall be computed (a) with respect to Eurodollar
Advances, on the basis of a year of 360 days and the actual number of days
elapsed (including the first day but excluding the last day) unless such
calculation would result in a usurious rate, in which case interest shall be
calculated on the basis of a year of 365 or 366 days, as the case may be and
(b) with respect to Prime Rate Advances, on the basis of a year of 365 or 366
days, as the case may be.

         SECTION 3.06.  Taxes.

         (a)     Payment by Borrowers.  All payments made by the Borrowers
hereunder (including, without limitation, payments under Article IV hereof) or
under the Notes shall be made free and clear of and without deduction for any
present or future income, stamp or other taxes, levies, imposts, deductions,
charges, fees, withholding, restrictions or conditions of any nature now or
hereafter imposed, levied, collected, withheld or assessed by any jurisdiction
(whether pursuant to United





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 35
<PAGE>   42
States Federal, state or local or foreign law) or by any political subdivision
or taxing authority thereof or therein, and all interest, penalties or similar
liabilities, excluding franchise taxes and taxes based on the overall net
income of the Administrative Agent, any other Co-Documentation Agent, any
Lender or its Applicable Lending Office (such non-excluded taxes are
hereinafter collectively referred to as the "Taxes").  If the Borrowers shall
be required by law to deduct or to withhold any Taxes from or in respect of any
amount payable hereunder, (i) unless the applicable Lender has failed to
deliver a United States Internal Revenue Service Form 1001 or 4224 or other
applicable form in accordance with Section 3.06(b) and the Borrowers have
notified the applicable Lender of such failure, the amount so payable shall be
increased to the extent necessary so that after making all required deductions
and withholdings (including Taxes on amounts payable to the Lender) the
applicable Lender receives an amount equal to the sum it would have received
had no such deductions or withholdings been made, (ii) the Borrowers shall make
such deductions or withholdings, and (iii) the Borrowers shall jointly and
severally pay the full amount deducted or withheld to the relevant taxation
authority in accordance with applicable law.  Whenever any Tax is payable by
the Borrowers, as promptly as possible thereafter the Borrowers shall send the
Administrative Agent and each affected Lender an official receipt showing
payment.  In addition, the Borrowers jointly and severally agree to pay any
present or future taxes, charges or similar levies (excluding franchise taxes,
and taxes based on the overall net income of the Administrative Agent, any
Co-Documentation Agent, any Lender or its Applicable Lending Office) which
arise from any payment made hereunder or from the execution, delivery,
performance, recordation or filing of, or otherwise with respect to, this
Agreement, the Notes or any other Loan Document (hereinafter referred to as
"Other Taxes").  The Borrowers jointly and severally will indemnify the
Administrative Agent, any Co-Documentation Agent and each Lender for the full
amount of Taxes or Other Taxes (including, any Taxes or Other Taxes on amounts
payable to the Administrative Agent, any Co-Documentation Agent, or any Lender
under this paragraph) paid by the Administrative Agent, any Co-Documentation
Agent or any Lender and any liability (including penalties, interest and
expenses) arising therefrom or with respect thereto, upon written demand by the
Administrative Agent, any Co-Documentation Agent or such Lender therefor.

         (b)     Withholding Tax Exemption Forms.  Each Lender that is not
incorporated under the laws of the United States of America or a state thereof
agrees that it will deliver to the Borrowers and the Administrative Agent two
(2) duly completed copies of United States Internal Revenue Service Form 1001
or 4224 certifying in either case that such Lender is entitled to receive
payments from the Borrowers under the Loan Documents without deduction or
withholding of any United States Federal income taxes.  Each Lender which so
delivers a Form 1001 or 4224 further undertakes to deliver to the Borrowers and
the Administrative Agent two (2) additional copies of such form (or a successor
form) on or before the date such form expires or becomes obsolete or after the
occurrence of any event requiring a change in the most recent form so delivered
by it and such amendments thereto or extensions or renewals thereof as may be
reasonably requested by the Borrowers or the Administrative Agent, in each case
certifying that such Lender is entitled to receive payments from the Borrowers
under the Loan Documents without deduction or withholding of any United States
Federal income taxes, unless an event (including without limitation any change
in treaty, law or regulation) has occurred prior to the date on which any such
delivery would otherwise be required which renders all such forms inapplicable
or which would prevent such Lender from duly completing and delivering any such
form with respect to it and such Lender advises the Borrowers





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 36
<PAGE>   43
and the Administrative Agent that it is not capable of receiving such payments
without any deduction or withholding of United States Federal income tax.

                                   ARTICLE IV

                        YIELD PROTECTION AND ILLEGALITY

         SECTION 4.01.  Increased Costs and Reduced Return.

         (a)     If any Lender shall have determined that any Regulatory Change
(other than with respect to taxes referred to in Section 3.06 hereof) shall (i)
change the basis of taxation of payments to the Lender of any amounts payable
hereunder with respect to any Eurodollar Advance (except for taxes based on the
overall net income of such Lender or its Applicable Lending Office), (ii)
impose, modify or deem applicable any reserve, special deposit or similar
requirement (other than Reserve Requirements used in the determination of the
Adjusted Eurodollar Rate) against any Eurodollar Advance or against assets held
by, or deposits with or for the account of, such Lender, or (iii) impose on the
applicable Lender any other condition regarding this Agreement, its Note or any
Eurodollar Advance and the result of any event referred to in clause (i), (ii)
or (iii) above shall be to increase the cost to the applicable Lender of making
or maintaining any Eurodollar Advance or the funding for any Eurodollar
Advance, or to reduce any amount received or receivable by the Lender hereunder
with respect to any such Advance, then, within ten (10) Business Days of
written demand by the applicable Lender (made through the Administrative
Agent), the Borrowers shall jointly and severally pay to the Administrative
Agent for the account of the applicable Lender such additional amounts as will
compensate the Lender for such increased costs or reductions in amount.

         (b)     If any Lender shall have determined that any Regulatory Change
shall impose, modify or deem applicable any capital adequacy or similar
requirement (including, without limitation, a request or requirement that
affects the manner in which the applicable Lender allocates capital resources
to its Commitment and Advances) that either affects or would affect the amount
of capital to be maintained by the applicable Lender as a consequence of its
commitments or obligations hereunder or reduces or would reduce the rate of
return on the Lender's capital to a level below that which the Lender could
have achieved but for such Regulatory Change as a consequence of its
commitments or obligations hereunder (taking into consideration the Lender's
policies with respect to capital adequacy), then, within ten (10) Business Days
of written demand by the applicable Lender (made through the Administrative
Agent), the Borrowers shall jointly and severally pay to the Administrative
Agent for the account of the applicable Lender such additional amounts as will
compensate the Lender for such cost of maintaining such increased capital or
such reduction in the rate of return on the Lender's capital.

         (c)     Before making any claims pursuant to Section 4.01(a) or
4.01(b) hereof, the applicable Lender, shall, if practicable, designate a
different Applicable Lending Office if such designation will avoid the need for
making such claim and will not, in the reasonable judgment of the applicable
Lender be otherwise disadvantageous to the applicable Lender.  If the
applicable Lender does make a claim pursuant to subsection 4.01(a) or 4.01(b)
hereof, it shall give notice to the





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 37
<PAGE>   44
Borrowers of the event by reason of which it is entitled to do so accompanied
by a certificate as described in subsection 4.01(d).

         (d)     A certificate of the applicable Lender claiming compensation
under this Section 4.01 shall be submitted by the Lender to the Administrative
Agent and the Borrowers, setting forth the Lender's reasons for invoking the
provisions of this Section 4.01, and shall be final and conclusive (absent
manifest error) as to the amount thereof, provided that any determination by a
Lender as to the occurrence and effect of a Regulatory Change for purposes of
this Section 4.01 shall be made on a reasonable basis.

         SECTION 4.02.  Basis for Determining Interest Rate Inadequate or
Unfair.  If on or prior to the first day of any Interest Period applicable to
Eurodollar Advances:

         (a)     The Administrative Agent determines (which determination shall
be conclusive) that quotations of interest rates for the relevant deposits
referred to in the definition of "Interbank Offered Rate" in Section 1.01 are
not being provided in the relative amounts or for the relative maturities for
purposes of determining the rate of interest for such Advances as provided in
this Agreement; or

         (b)     The Required Lenders determine (which determination shall be
conclusive) and notify the Administrative Agent that the relevant rates of
interest referred to in the definition of "Interbank Offered Rate" in Section
1.01 on the basis of which the rate of interest for such Advances for such
Interest Period is to be determined do not accurately reflect the cost to the
Lenders of making or maintaining such Advances for such Interest Period;

then the Administrative Agent shall give Borrowers prompt notice thereof
specifying the relevant amounts or periods, and so long as such condition
remains in effect, the Lenders shall be under no obligation to make additional
Eurodollar Advances or to Convert Prime Rate Advances into Eurodollar Advances
and Borrowers shall, on the last day(s) of the then current Interest Period(s)
for the outstanding Advances of the affected Type, either prepay such Advances
or Convert such Advances into Prime Rate Advances in accordance with the terms
of this Agreement.

         SECTION 4.03.  Illegality.  If, after the date of this Agreement, any
Regulatory Change shall make it unlawful or impossible for the applicable
Lender (or its Applicable Lending Office) to make, maintain or fund its
Eurodollar Advances, the applicable Lender shall forthwith give notice thereof
to the Administrative Agent and the Borrowers, whereupon until such Lender
notifies the Borrowers that the circumstances giving rise to such suspension no
longer exist, the obligation of the applicable Lender to make Eurodollar
Advances and to Convert Prime Rate Advances into Eurodollar Advances hereunder
shall be suspended.  Before giving any notice to the Borrowers pursuant to this
Section 4.03, the applicable Lender shall, if practicable, designate a
different Applicable Lending Office if such designation will avoid the need for
giving such notice and will not, in the reasonable judgment of the Lender, be
otherwise disadvantageous to the Lender.

         SECTION 4.04.  Treatment of Affected Advances:  If the Eurodollar
Advances of any Lender (hereinafter called "Affected Advances") are to be
Converted pursuant to Section 4.02 or 4.03 hereof, such Lender's Affected
Advances shall be automatically Converted into Prime Rate Advances on the





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 38
<PAGE>   45
last day(s) of the then current Interest Period(s) for the Affected Advances
(or, in the case of a Conversion required by Section 4.01(b) or 4.03 hereof, on
such earlier date as such Lender may specify to Borrowers, with a copy to the
Administrative Agent) and, unless and until such Lender gives notice as
provided below that the circumstances specified in Section 4.01 or 4.03 hereof
which gave rise to such Conversion no longer exist:

                 (a)      To the extent that such Lender's Affected Advances
         have been so Converted, all payments and prepayments of principal
         which would otherwise be applied to such Lender's Affected Advances
         shall be applied instead to its Prime Rate Advances; and

                 (b)      All Advances which would otherwise be made or
         Continued by such Lender as Eurodollar Advances shall be made as or
         Converted into Prime Rate Advances and all Advances of such Lender
         which would otherwise be Converted into Eurodollar Advances shall be
         Converted instead into (or shall remain as) Prime Rate Advances; and

If such Lender gives notice to Borrowers (with a copy to the Administrative
Agent) that the circumstances specified in Section 4.01 or 4.03 hereof which
gave rise to the Conversion of such Lender's Affected Advances pursuant to this
Section 4.04 no longer exist (which such Lender agrees to do promptly upon such
circumstances ceasing to exist) at a time when Eurodollar Advances are
outstanding, such Lender's Prime Rate Advances shall be automatically
Converted, on the first day(s) of the next succeeding Interest Period(s) for
such outstanding Eurodollar Advances to the extent necessary so that, after
giving effect thereto, all Advances held by the Lenders holding Affected
Advances and by such Lender are held Pro Rata (as to principal amounts, Types,
and Interest Periods) in accordance with their respective Commitments.

         SECTION 4.05.  Funding Losses.  The Borrowers shall jointly and
severally compensate each Lender, immediately upon receipt of such Lender's
certificate as to amount (which shall be conclusive in the absence of manifest
error), for all losses, expenses and liabilities (including, without
limitation, any loss, expense or liability incurred by reason of the
liquidation or reemployment of deposits or other funds acquired by the Lender
to fund or maintain any Advance (but excluding loss of anticipated profits),
and including any costs and expenses arising under or in connection with any
interest rate exchange agreement or similar agreement relating to any such
agreement, whether or not theretofore disclosed to the Borrowers, entered into
by such Lender in connection with the funding or maintenance of any Eurodollar
Advance), (a) if for any reason (other than a default by the applicable Lender)
any Borrower fails to borrow or Convert any Eurodollar Advance after a notice
(whether or not withdrawn by such Borrower) has been given to the
Administrative Agent requesting such Advance or Conversion, as applicable, (b)
if any Borrower makes any payment of principal of any Eurodollar Advance or
makes any Conversion of a Eurodollar Advance on any day other than on the last
day of the Interest Period relating to such Advance for any reason (including,
without limitation, prepayment or acceleration), or (c) if any prepayment of
any Eurodollar Advance is not made on any date specified in a notice of
prepayment given by any Borrower.





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 39
<PAGE>   46





                                   ARTICLE V

                             CONDITIONS OF LENDING

         SECTION 5.01.  Conditions to the Effectiveness of this Agreement.  The
effectiveness of this Agreement is subject to the fulfillment, in a manner
satisfactory to the Co-Documentation Agents and each Lender, of each of the
following conditions precedent:

         (a)     Amendment Fees; Payment of Fees.  Borrowers shall have paid to
the Co-Documentation Agents and the Lenders any and all fees, costs, expenses
and taxes then payable by Borrowers pursuant to this Agreement relating to the
amendments contemplated hereby.

         (b)     Representations and Warranties; No Event of Default.  The
representations and warranties contained in Section 6.01 of this Agreement and
in each other (other than, as to Loan Documents delivered or effective as of a
date prior to the Closing Date, representations and warranties limited by their
terms to the date given) and each certificate or other writing delivered to the
Administrative Agent or any Lender pursuant hereto shall be correct on and as
of the Closing Date as though made on and as of such date; and, no Event of
Default or Potential Default shall have occurred and be continuing on the
Closing Date or would result from the consummation of the Related Transactions.

         (c)     Legality.  The modifications contemplated hereby and the
transactions contemplated herein shall not contravene any law, rule or
regulation.

         (d)     Closing of Amoco Purchase Agreement.  All conditions to the
closing of the transactions contemplated by the Amoco Purchase Agreement shall
have been satisfied and such transactions shall be ready for closing subject
only to the advancing of Loan proceeds hereunder.

         (e)     Delivery of Documents.  The Administrative Agent shall have
received on or before the Closing Date the following, each duly executed and in
form and substance satisfactory to the Administrative Agent and each Lender
and, unless indicated otherwise, dated the date hereof:

              (i)         the Notes;

             (ii)         the First Amended and Restated Modification
Agreement;

            (iii)         the Oklahoma Mortgage and any other Security
Documents required by the Administrative Agent;

             (iv)         Letters in Lieu of Transfer Orders executed by
Acquisitions in blank, together with a list of the names and addresses of all
presently anticipated purchasers of Hydrocarbons attributable to the Petroleum
and Natural Gas Rights of Acquisitions and such other information with respect
to such purchasers as the Administrative Agent may reasonably request;





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 40
<PAGE>   47
              (v)         a copy of the resolutions adopted by the Board of
Directors of each Credit Party, certified as of the Closing Date by an
authorized officer thereof, authorizing (A) the transactions contemplated by
this Agreement, and (B) the execution, delivery and performance by each Credit
Party of the Loan Documents to which it is a party that are executed in
connection herewith;

             (vi)         a certificate of an authorized officer of each Credit
Party, certifying the names and true signatures of the officers of each such
Credit Party authorized to sign each Loan Document together with evidence of
the incumbency of such authorized officer;

            (vii)         a certificate, dated as of a current date, of the
appropriate official(s) of the jurisdiction of incorporation or organization of
each Credit Party and the States of Mississippi, Oklahoma and Texas and as to
ING and the ING Subsidiaries, Louisiana, Texas and Mississippi, certifying as
to the authority to transact business and good standing of, and the payment of
taxes by, each Credit Party in such jurisdiction, as applicable;

           (viii)         a copy of the charter of each Credit Party, certified
as of a current date by the appropriate official of the jurisdiction of
incorporation or organization of such Credit Party and as of the Closing Date
by an authorized officer of such Credit Party;

             (ix)         a copy of the by-laws of each Credit Party, certified
as of the Closing Date by an authorized officer of such Credit Party;

              (x)         a certificate of the president of CRI as to the
solvency of each Credit Party, substantially in the form of Exhibit C hereto as
of the Closing Date;

             (xi)         opinions of counsel to the Credit Parties as to such
matters as the Administrative Agent may reasonably request;

            (xii)         the Second Amended and Restated Contribution and
Reimbursement Agreement among the Credit Parties;

           (xiii)         the Acquisition Engineering Report;

            (xiv)         the Second Amendment to Pledge Agreement;

             (xv)         evidence of the filing of all required notifications
by Amoco Production Company and Acquisitions under the Hart Scott Rodino
Antitrust Improvements Act of 1976, as amended, and expiration or early
termination of all waiting periods thereunder; and

            (xvi)         such other agreements, instruments, approvals,
opinions and other documentation as the Administrative Agent or any Lender may
reasonably request; and

         SECTION 5.02.  Conditions Precedent to the Advances and Issuances of
Letters of Credit.  The obligation of each Lender to make any Advance after the
Closing Date (other than an Advance





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 41
<PAGE>   48
pursuant to subsection 2.01(b)(ii)) and the obligations of the Administrative
Agent to issue any Letter of Credit after the Closing Date is subject to the
fulfillment, in a manner satisfactory to the Administrative Agent and each
Lender, of each of the following conditions precedent:

         (a)     Payment of Fees, Etc.  The Borrowers shall have paid any and
all fees, costs, expenses and taxes then payable by the Borrowers pursuant to
this Agreement and Section 10.04 hereof.

         (b)     Representations and Warranties; No Event of Default.  The
representations and warranties contained in Section 6.01 of this Agreement and
in each other Loan Document (but excluding those representations and warranties
specifically limited by their terms to another date) and each certificate or
other writing delivered to the Administrative Agent or any Lender pursuant
hereto shall be correct on and as of the Borrowing Date as though made on and
as of such date; and no Event of Default or Potential Default shall have
occurred and be continuing on the Borrowing Date or would result from the
making of the Advance or issuance of the Letter of Credit.

         (c)     Legality.  The making of such Advance or issuance of the
Letter of Credit shall not contravene any law, rule or regulation applicable to
the Administrative Agent or any Lender.

         (d)     Advance Request Form. The Administrative Agent shall have
received an Advance Request Form pursuant to Section 2.05 hereof with respect
to such Advance or Letter of Credit and, with respect to each Letter of Credit
and the documentation required by the Administrative Agent in accordance with
subsection 2.01(b)(i).

         (e)     Proceedings; Receipt of Documents.  All proceedings in
connection with the making of the Advance or issuance of Letter of Credit and
all documentation incidental thereto, shall be satisfactory to the
Administrative Agent and each Lender and the Administrative Agent and each
Lender shall have received all such information and such counterpart originals
or certified or other copies of such documentation as the Administrative Agent
or any Lender may reasonably request.

                                   ARTICLE VI

                         REPRESENTATIONS AND WARRANTIES

         SECTION 6.01.  Representations and Warranties of Each Company.  Each
Company represents and warrants to the Administrative Agent and each Lender as
follows:

         (a)     Organization, Good Standing, Etc.  Holdings and each of its
Subsidiaries (i) is a corporation duly organized, validly existing and in good
standing under the laws of the jurisdiction of its incorporation, (ii) has all
requisite power and authority to conduct its business as now conducted and as
presently contemplated and to execute and deliver each Loan Document to which
it is a party and to make the borrowings hereunder and to consummate the
transactions contemplated hereby and thereby and (iii) is duly qualified to do
business and is in good standing in each jurisdiction in which the character of
the properties owned or leased by it or in which the transaction of its
business makes such qualification necessary and in which the failure to be so
qualified would cause a Material Adverse Change.





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 42
<PAGE>   49
         (b)     Authorization, Etc.  The execution, delivery and performance
by each Credit Party of each Loan Document to which it is a party (i) have been
duly authorized by all necessary corporate action, (ii) do not and will not
contravene its charter or by-laws, any law or any contractual restriction
binding on or otherwise affecting it or any of its properties, (iii) do not and
will not result in or require the creation of any Lien, other than pursuant to
any Loan Document upon or with respect to any of its properties and in favor of
the Lenders and (iv) do not and will not result in any suspension, revocation,
impairment, forfeiture or nonrenewal of any permit, license, authorization or
approval applicable to its operations or any of its properties.

         (c)     Governmental Approvals.  Except for notices, filings,
authorization, approvals and application actions all of which have been made or
obtained, no authorization or approval or other action by, and no notice to or
filing with, any Governmental Authority is required to permit a Credit Party to
duly execute, deliver and perform its obligations under any Loan Document.

         (d)     Enforceability of Loan Documents.  This Agreement is, and each
other Loan Document, when delivered, will be, a legal, valid and binding
obligation of each Credit Party which is a party thereto, enforceable against
such Credit Party in accordance with its terms, except to the extent that (i)
the enforceability of such Loan Document is limited by any applicable
bankruptcy, insolvency, reorganization, moratorium or similar laws from time to
time in effect affecting generally the enforcement of creditors' rights and
remedies and by general principles of equity, (ii) any Loan Document creates a
security interest in that part of the Collateral, if any, which constitutes a
"security" (as defined in the UCC), such security interest will not be created
until steps necessary to the perfection of such security interest are taken
pursuant to Article 8 or Article 9 of the UCC and (iii) (without limiting the
applicability of the foregoing to the Security Documents) the validity or
enforceability of any Lien on real property or interest in real property which
is purported to be conveyed by the Security Documents is subject to the
recordation of appropriate instruments under local real property law or
applicable federal law.

         (e)     Subsidiaries; Capitalization.  As of the Closing Date, no
Credit Party has any Subsidiaries other than as set forth in Schedule 6.01(e).
Schedule 6.01(e) hereto is a complete and correct description of the name,
jurisdiction of incorporation and authorized and outstanding Capital Stock of
each Subsidiary of each Credit Party and the percentage interest each Credit
Party holds in each of its Subsidiaries on the Closing Date.  All of the
outstanding Capital Stock of each Subsidiary of each Credit Party has been
validly issued, is fully paid, is nonassessable and is not subject to any
restriction on transfer except for restrictions imposed by applicable federal
and state securities laws.  All the issued and outstanding shares of Capital
Stock of each such Subsidiary are free and clear of all Liens other than those
in favor of the Administrative Agent granted pursuant to the Security Documents
and such shares have been issued in compliance with all applicable state and
federal laws concerning the issuance of securities.  There are no preemptive or
other outstanding rights, options, warrants, conversion rights or similar
agreements or understandings for the purchase or acquisition from any such
Subsidiary or any Credit Party of any shares of Capital Stock or other
securities of any such Subsidiary.  Holdings has the unrestricted right to
pledge the Capital Stock of CRI, Coho Canada, Coho Shell, and ING under the
terms of the Holdings Pledge Agreement.  CRI has the unrestricted right to
pledge the Capital Stock of Acquisitions under the terms of the Pledge
Agreement. Coho Canada has the unrestricted right to enter into a negative
pledge with respect to





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 43
<PAGE>   50
the Capital Stock of CRI under the terms of the Coho Canada Negative Pledge
Agreement.  CRI has the unrestricted right to pledge the Capital Stock of ING
under the terms of the CRI Security Agreement.  ING has the unrestricted right
to pledge the Capital Stock of the ING Subsidiaries under the terms of the ING
Pledge Agreement.  The Production Company has the unrestricted right to pledge
the Capital Stock of Exploration under the terms of the Mid Louisiana Pledge
Agreement.

         (f)     Litigation.  Except set forth as Schedule 6.01(f), there is no
pending or, to the knowledge of any Company, threatened action, suit or
proceeding affecting Holdings or any of its Subsidiaries before any court or
other Governmental Authority or any arbitrator which may cause a Material
Adverse Change.

         (g)     Financial Condition.  The Financial Statements fairly present
the financial condition of the Credit Parties subject thereto as at the
respective dates thereof and their results of operations for the fiscal periods
ended on such respective dates, all in accordance with GAAP consistently
applied, and since September 30, 1997, there has been no Material Adverse
Change.

         (h)     Compliance with Law, Etc.  Neither Holdings nor any of its
Subsidiaries is (i) in violation of its charter or by-laws, any law or (ii) in
violation of any term of any agreement or instrument binding on or otherwise
affecting it or any of its properties, the effect of which violation would
cause a Material Adverse Change.

         (i)     ERISA.  (i) No Termination Event has occurred nor is
reasonably expected to occur with respect to any Employee Plan, (ii) the most
recent annual report (Form 5500 Series) with respect to each Employee Plan,
including Schedule B (Actuarial Information) thereto, copies of which have been
filed with the Internal Revenue Service and delivered to the Administrative
Agent, is complete and correct and fairly presents the funding status of such
Employee Plan, and since the date of such report there has been no material
adverse change in such funding status, and (iii) no Employee Plan has incurred
an "accumulated funding deficiency" within the meaning of Section 412(a) of the
Internal Revenue Code in excess of Two Hundred Fifty Thousand Dollars
($250,000.00) at any time during the previous sixty (60) months unless waived
pursuant to Section 412(c)(8) of the Internal Revenue Code.  Neither Holdings
nor any of its Affiliates has incurred any withdrawal liability under ERISA
with respect to any Multiemployer Plan, and neither Company is aware of any
facts indicating that Holdings or any of its Affiliates may in the future incur
any such withdrawal liability.  Each Employee Plan now maintained or maintained
during the preceding five (5) years by Holdings or any of its Affiliates has
complied in all material respects in form and in operation with all applicable
laws.  Neither Holdings nor any of its Affiliates maintains or has maintained a
Plan that is or was part of a multiple employer welfare arrangement (as defined
in section 3(40) of ERISA), and no welfare benefit plan (as defined in section
3(1) of ERISA) now maintained or maintained during the preceding five (5) years
by Holdings or any of its Affiliates currently provides or is obligated to
provide benefits to former employers of Holdings or any of its Affiliates other
than pursuant to continuing health care requirements of ERISA or the Internal
Revenue Code.  Each Plan may be amended or terminated without the consent of
any party other than the parties thereto.  There is and has been no actual,
anticipated, threatened or expected litigation, or arbitration or government
audit or proceeding concerning or involving any Plan which could cause a
Material Adverse Change.  All reporting and disclosure requirements with
respect to





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 44
<PAGE>   51
each Plan have been timely satisfied.  There have been no prohibited
transactions (as defined in sections 406 or 407 of ERISA or section 4975 of the
Internal Revenue Code excluding prohibited transactions for which an exemption
is available under ERISA or the Internal Revenue Code) involving any Plan.
There have been no failures to comply in any material respect with the
continuing health care coverage requirements of ERISA or the Internal Revenue
Code.

         (j)     Taxes, Etc.  All Federal, state and local tax returns and
other reports required by applicable law to be filed by Holdings or any of its
Subsidiaries have been filed, and all taxes, assessments and other governmental
charges imposed upon Holdings or any of its Subsidiaries or any property of any
such Person and which have become due and payable on or prior to the Closing
Date have been paid, except to the extent contested in good faith by proper
proceedings which stay the imposition of any penalty, fine or Lien resulting
from the non-payment thereof and with respect to which adequate reserves have
been set aside for the payment thereof.

         (k)     Regulation U.  Neither Holdings nor any of its Subsidiaries is
engaged in the business of extending credit for the purpose of purchasing or
carrying margin stock (within the meaning of Regulation U issued by the Board
of Governors of the Federal Reserve System), and no proceeds of any Advance
will be used to purchase or carry any margin stock or to extend credit to
others for the purpose of purchasing or carrying any margin stock.

         (l)     Title to Properties.  Each of Holdings and its Subsidiaries
has good and defensible title to all of its properties and assets (including
the Amoco Properties), and the properties and assets of Holdings and its
Restricted Subsidiaries (including the Amoco Properties) are free and clear of
all Liens except such as are permitted by Section 7.02(a) hereof.  Acquisitions
has delivered to the Administrative Agent a complete and accurate copy of the
Amoco Purchase Agreement and all documents and instruments executed in
connection therewith, including all amendments, supplements and other
modifications thereto.

         (m)     Credit Arrangements.  Schedule 6.01(m) hereto is a complete
and correct list of each credit agreement, guaranty or other agreement,
instrument or arrangement in effect as of the date hereof and providing for or
relating to the extension of credit (excluding agreements and arrangements for
the purchase of goods and services in the normal course of business, but
including agreements and arrangements for the issuance of letters of credit or
for acceptance financing) in respect of which Holdings or any of its Restricted
Subsidiaries is or may become directly or contingently liable in a principal or
face amount in excess of One Hundred Thousand Dollars ($100,000.00).

         (n)     Nature of Business.  Neither Holdings nor any of its
Subsidiaries is engaged in any business other than the purchase of, exploration
for, and the production, transportation, storage and sale of, Hydrocarbons and
other activities necessary or useful to facilitate the profitable enhancement
of Hydrocarbon value.

         (o)     Adverse Agreements, Etc.  Neither Holdings nor any of its
Subsidiaries is a party to any agreement or instrument, or subject to any
charter or other corporate restriction or any judgment,





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 45
<PAGE>   52
order, regulation, ruling or other requirement of a court or other Governmental
Authority, which causes or in the future may cause a Material Adverse Change.

         (p)     Holding Company and Investment Company Acts.  Neither Holdings
nor any of its Subsidiaries is (i) a "holding company" or a subsidiary company
of a "holding company" or an "affiliate" of a "holding company", as such terms
are defined in the Public Utility Holding Company Act of 1935, as amended, or
(ii) an "investment company" or an "affiliated person" or "promoter" of, or
"principal underwriter" of or for, an "investment company", as such terms are
defined in the Investment Company Act of 1940, as amended.

         (q)     Permits, Etc.  Holdings and each of its Subsidiaries maintains
all permits, licenses, authorizations and approvals required for it lawfully to
own, lease, manage or operate each business currently owned, leased, managed or
operated by it and which the failure to so maintain would cause a Material
Adverse Change.  No condition exists or event has occurred which, in itself or
with the giving of notice or lapse of time or both, would result in the
suspension, revocation, impairment, forfeiture or non-renewal of any such
permit, license, authorization or approval, and there is no claim that any
thereof is not in full force and effect.

         (r)     Full Disclosure.  No Loan Document or schedule or exhibit
thereto and no certificate, report, statement or other document and/or
information furnished to the Administrative Agent or any Lender in connection
herewith or with the consummation of the transactions contemplated by the Loan
Documents, contains or contained, as applicable, as of the date of delivery of
such Loan Documents, any material misstatement of fact or omits to state a
material fact or any fact necessary to make the statements contained therein
not materially misleading.  There is no fact existing which could cause a
Material Adverse Change and which has not been set forth in a Schedule hereto
or otherwise disclosed to the Administrative Agent in writing.

         (s)     Environmental Conditions.  Except as disclosed in Schedule
6.01(s) hereto, (i) the operations of Holdings and each of its Subsidiaries
comply in all material respects with all Environmental Laws and, to the
Companies' knowledge, no conditions exist or are likely to exist during the
term of this Agreement which, individually or in the aggregate, would subject
Holdings or any of its Subsidiaries to material damages, penalties, injunctive
relief or cleanup costs under any Environmental Law or which, individually or
in the aggregate, require or are likely to require any material Remedial Action
under any Environmental Law; (ii) Holdings and each of its Subsidiaries has
obtained all material Environmental Permits necessary for its operation, and
all such Environmental Permits are in good standing; (iii) neither Holdings nor
any of its Subsidiaries is a party to any litigation or formal administrative
proceeding alleging the violation of any Environmental Law or asserting that
Holdings or any of its  Subsidiaries is required to take any Remedial Action
under any Environmental Law; (iv) neither Holdings nor any of its Subsidiaries
is subject to any outstanding written order or agreement with any Governmental
Authority or other Person respecting (A) any Environmental Law, (B) any
Remedial Action under any Environmental Law or (C) any Environmental Claim
under any Environmental Law; (v) to each Company's knowledge, none of the
operations of Holdings or any of its Subsidiaries is the subject of any pending
or threatened investigation by a Governmental Authority evaluating whether any
Remedial Action under any Environmental Law is needed; (vi) neither Holdings
nor any of its Subsidiaries has





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 46
<PAGE>   53
filed any notice under federal or state law indicating past or present
treatment, storage or disposal of a hazardous waste as defined under 40 C.F.R.
Parts 260 or 270 (in effect as of the date hereof) or any state equivalent, or
reporting a Release of a Contaminant; (vii) except as permitted under any
Environmental Law, neither Holdings nor any of its Subsidiaries has experienced
a material Release of any Contaminant, and, except as permitted under and in
compliance with applicable Environmental Law, there has been no material
voluntary disposal, use, storage, recycling or treatment of any Contaminant (A)
on, under or at any property of Holdings or any of its Subsidiaries (or in
tanks or other facilities thereon) or (B) by Holdings or any of its
Subsidiaries at any other location, which, if known to be present on such
property, or present in soils or ground water, would require Remedial Action
under any Environmental Law, except for Remedial Action required after
depletion with respect to each production facility located on a portion of the
Collateral, the cost of which will not exceed One Hundred Thousand Dollars
($100,000.00), (viii) no recorded Lien and, to each Company's knowledge, no
unrecorded Lien, in favor of any Governmental Authority relating to (A) any
liability under any Environmental Law or (B) damages arising from or costs
incurred by such Governmental Authority in response to a Release of a
Contaminant into the environment has been filed or attached to any facility of
Holdings or any of its Subsidiaries; and (ix) within the last thirty-six (36)
months, neither Holdings nor any of its Subsidiaries has been subject to a
written order or binding written agreement with any Governmental Authority or
other Person respecting (A) any Environmental Law, (B) any Remedial Action
under any Environmental Law or (C) any Environmental Claim, and neither
Holdings nor any of its Subsidiaries has performed any Remedial Action, the
aggregate cost of which exceeded One Hundred Thousand Dollars ($100,000.00).
For purposes of this Section 6.01(s), "knowledge" means the actual knowledge of
any officer of any Company.

         (t)     Principal Place of Business; Location of Collateral. The
principal place of business and chief executive office of each Credit Party and
the place where each such Credit Party keeps its books and records is located
at the address of such Credit Party set forth on Schedule 6.01(t).  The title
opinions delivered to Administrative Agent in connection with the previously
executed Loan Documents identify all of the Borrowers material Petroleum and
Natural Gas Rights as of the Closing Date other than the Amoco Properties.
Schedule 6.01(t) specifically sets forth all locations where each Credit Party
maintains the Collateral that it owns and all other locations where such Credit
Party maintains a place of business as of the Closing Date. Such title opinions
and Schedule 6.01(t) correctly identify each location where each Credit Party's
inventory or equipment which constitutes Collateral (other than mobile goods)
is located.  No Persons have possession of any Collateral other than (i)
Hydrocarbons held by operators engaged with respect to Borrowers' Petroleum and
Natural Gas Rights; (ii) the Persons who hold hedge accounts of the Credit
Parties other than Coho Canada; (iii) the Credit Parties other than Coho
Canada; and (iv) such other Persons identified to the Administrative Agent
pursuant to the Security Documents. As of the Closing Date, Koch Oil Company,
EOTT Energy, Mid Louisiana Marketing Company  and Amoco are the only purchasers
of Borrowers' Hydrocarbons produced from Petroleum and Natural Gas Rights which
constitute Collateral owned by the Borrowers and the purchasers identified on
the list delivered in accordance with Section 5.01(d)(v) are the only
purchasers of Exploration's or Acquisitions' Hydrocarbons produced from
Petroleum and Natural Gas Rights which constitute Collateral owned by
Exploration or Acquisitions.  None of the Collateral constituting "goods" has
been located in any





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 47
<PAGE>   54
location not identified in Schedule 6.01(t) or in such title opinions within
the past four (4) months from the date hereof other than with respect to mobile
goods.

         (u)     Corporate Name.  The exact corporate name of each Credit Party
as it appears in its certificate of incorporation is as set forth on Schedule
6.01(t) and no Credit Party has done business in any location under any other
name.

         (v)     Security Interests and Liens.  The Security Documents create
in favor of Administrative Agent for the benefit of the Lenders valid and
enforceable Liens in the Collateral described therein which secure the payment
and performance of the Obligations that are described therein, including
without limitation, all future Advances pursuant to this Agreement and the
Notes, all contingent Obligations arising in connection with the Letters of
Credit and all extensions, renewals, and other modifications thereof.  Upon
delivery to the Administrative Agent from time to time of any promissory note
evidencing Permitted Coho Shell Advances or any Permitted Intercompany Advances
and any other Collateral the possession of which is necessary to perfect the
security interest therein, the Liens created by the Loan Documents shall
constitute perfected, first priority Liens upon the property described therein
which shall be superior and prior to the rights of all third Persons now
existing or hereafter arising except for Liens permitted by Section 7.02(a).

                                  ARTICLE VII

                                   COVENANTS

         SECTION 7.01.  Affirmative Covenants.  So long as any of the
Obligations shall remain unpaid or any Lender has any Commitment hereunder,
each Company covenants and agrees, unless the Required Lenders shall otherwise
consent in writing, as follows:

                 (a)      Stockholders' Equity. Holdings and its Restricted
         Subsidiaries will maintain its Stockholders' Equity in an amount at
         all times not less than the sum of (A) One Hundred Eight Million
         Dollars ($108,000,000.00) plus (B) fifty percent (50%) of the
         Consolidated Net Income of Holdings for each fiscal quarter beginning
         with the fiscal quarter ended March 31, 1998, plus (c) seventy-five
         percent (75%) of the cash proceeds (less reasonable and customary fees
         and expenses and underwriter's discounts) of any sales of Capital
         Stock of Holdings on or after the Closing Date.  If Consolidated Net
         Income of Holdings for any fiscal year is negative, no adjustment to
         the requisite level of Stockholders' Equity shall be made.

                 (b)      Interest Coverage Ratio.  Holdings will maintain an
         Interest Coverage Ratio measured at the end of each fiscal quarter for
         the four fiscal quarters then most recently ended of not less than 2.5
         to 1.0;

                 (c)      Current Ratio.  Holdings will at all times maintain a
         minimum Consolidated Current Ratio of 1.0 to 1.0;

                 (d)      Reporting Requirements.  The Companies will furnish
         to the Administrative Agent and each Lender:





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 48
<PAGE>   55
                      (i)         as soon as available and in any event within
                 sixty (60) days after the end of each of the first three
                 quarters of each fiscal year of Holdings, (a) consolidated and
                 consolidating balance sheets of Holdings and its Restricted
                 Subsidiaries as at the end of such quarter, and consolidated
                 and consolidating statements of earnings and cash flow of
                 Holdings and its Restricted Subsidiaries for such quarter and
                 for the period commencing at the end of the immediately
                 preceding fiscal year and ending with the end of such quarter,
                 (b) consolidated and consolidating balance sheets of each
                 Unrestricted Subsidiary and the applicable Unrestricted
                 Subsidiary's Subsidiaries as at the end of such quarter and
                 consolidated and consolidating statements of earnings and cash
                 flow of each Unrestricted Subsidiary and the applicable
                 Unrestricted Subsidiary's Subsidiaries for such quarter and
                 for the period commencing at the end of the immediately
                 preceding fiscal year and ending with the end of such quarter,
                 all such financial statements to set forth in comparative form
                 the corresponding figures for the corresponding date or period
                 of the immediately preceding fiscal year, all in reasonable
                 detail and prepared, in the case of the consolidated balance
                 sheets and statements, in accordance with GAAP (except for the
                 absence of any footnotes required by GAAP), duly certified by
                 the chief financial officer of Holdings (or in the case of
                 Unrestricted Subsidiaries, by an authorized officer thereof)
                 as (A) fairly presenting the financial condition of the
                 Persons subject thereof at the end of such quarter and the
                 results of the operations of the Persons subject thereof for
                 such periods (subject to normal year-end audit adjustments),
                 and (B), in the case of the consolidated balance sheets and
                 statements, having been prepared in accordance with GAAP.

                      (ii)        as soon as available and in any event within
                 one hundred twenty (120) days after the end of each fiscal
                 year of Holdings,

                                  (A)      consolidated and consolidating
                          balance sheets of Holdings and its Restricted
                          Subsidiaries as at the end of such fiscal year, and
                          consolidated and consolidating statements of earnings
                          and cash flow of Holdings and its Restricted
                          Subsidiaries for such fiscal year, setting forth in
                          comparative form the corresponding figures for the
                          immediately preceding fiscal year, all in reasonable
                          detail and prepared, in the case of the consolidated
                          balance sheets and statements, in accordance with
                          GAAP and (1) in the case of consolidated balance
                          sheets and statements, accompanied by a report and an
                          opinion that such balance sheets and statements have
                          been prepared in accordance with GAAP, of an
                          independent certified public accountant of recognized
                          standing selected by Holdings and satisfactory to the
                          Lenders (which opinion shall not be qualified in any
                          material respect), together with a written statement
                          of such accountants (x) to the effect that in making
                          the examination necessary for their certification of
                          such financial statements they have not obtained any
                          knowledge of the existence of an Event of Default or
                          any Potential Default, or (y) if such accountants
                          shall have obtained any knowledge of the existence of
                          an Event of Default or Potential Default, describing
                          the nature thereof, and (2) in the case of
                          consolidating balance sheets and statements, duly
                          certified





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 49
<PAGE>   56
                          by the chief financial officer of Holdings as fairly
                          presenting the financial condition of Holdings and
                          its Restricted Subsidiaries at the end of, and the
                          results of operations of Holdings and its Restricted
                          Subsidiaries for, such fiscal year; and

                                  (B)      consolidated and consolidating
                          balance sheets of each Unrestricted Subsidiary and
                          the applicable Unrestricted Subsidiary's Subsidiaries
                          as at the end of such fiscal year, and consolidated
                          and consolidating statements of earnings and cash
                          flow of each Unrestricted Subsidiary and the
                          applicable Unrestricted Subsidiary's Subsidiaries for
                          each fiscal year, setting forth in comparative form
                          the corresponding figures for the immediately
                          preceding fiscal year, all in reasonable detail and
                          prepared, in the case of the consolidated balance
                          sheets and statements, in accordance with GAAP and
                          duly certified by the chief financial officer of the
                          applicable Unrestricted Subsidiary as fairly
                          presenting the financial condition of the applicable
                          Unrestricted Subsidiary and its Subsidiaries at the
                          end of, and the results of operations of the
                          applicable Unrestricted Subsidiary and its
                          Subsidiaries for, such fiscal year;

                    (iii)         as soon as available and in any event within
         sixty (60) days after the end of each calendar quarter, a Production
         Report for such quarter;

                      (iv)        simultaneously with the delivery of the
         financial statements required by paragraphs (i) and (ii) above, a
         certificate of the chief financial officer of Holdings, (A) stating
         that such officer has reviewed the provisions of this Agreement and
         the other Loan Documents and has made or caused to be made under his
         supervision a review of the condition and operations of Holdings and
         its Subsidiaries during the period covered by such financial
         statements with a view to determining whether Holdings and its
         Subsidiaries were in compliance with all of the provisions of such
         Loan Documents, and that such review has not disclosed, and such
         officer has no knowledge of, the existence during such period of an
         Event of Default or Potential Default or if an Event of Default or
         Potential Default existed, describing the nature and period of
         existence thereof and the action which the Companies propose to take
         with respect thereto, and (B) setting forth data and calculations
         demonstrating in reasonable detail compliance with the provisions of
         subsections (a), (b) and (c) of this Section 7.01 as of the end of such
         period and the calculation of the ratio of Consolidated Indebtedness
         to EBITDA of Holdings and its Restricted Subsidiaries for the four
         fiscal quarters then most recently ended;

                      (v)         thirty (30) days before the end of each
         fiscal year of Holdings, a projected cash flow statement for the
         fiscal year immediately succeeding such fiscal year containing all
         projected sources and uses of cash for Holdings and its Restricted
         Subsidiaries (on a consolidated basis), disclosing all assumptions
         made with respect to general economic, financial and market conditions
         utilized in the preparation of such projected cash flow statement and
         certified by an officer of Holdings to be, to the best of such
         officer's knowledge, (a) based upon reasonable estimates and
         assumptions, all of





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 50
<PAGE>   57
         which are fair in light of then current conditions, (b) prepared on
         the basis of the assumptions stated therein and (c) reflective of
         Holdings estimates of the results of operations and other matters
         projected therein;

                      (vi)        promptly upon receipt thereof, copies of all
         financial reports (including, without limitation, management letters),
         if any, submitted to Holdings or any of its Subsidiaries by its
         auditors in connection with any annual or interim audit of the books
         thereof;

                    (vii)         as soon as possible and in any event within
         five (5) days after obtaining knowledge of the occurrence of an Event
         of Default or a Potential Default the written statement of the chief
         financial officer of Holdings, setting forth the details of such Event
         of Default or Potential Default and the action which the Companies
         proposes to take with respect thereto;

                   (viii)         promptly after the sending or filing thereof,
         copies of all statements, reports and other information which Holdings
         or any of its Subsidiaries sends to its security-holders generally or
         files with the Securities and Exchange Commission or any national
         securities exchange;

                      (ix)        (A) as soon as possible and in any event (1)
         within thirty (30) days after Holdings or any of its Affiliates knows
         or has reason to know that any Termination Event described in clause
         (a) of the definition of Termination Event with respect to any
         Employee Plan has occurred, and (2) within ten (10) days after
         Holdings or any of its Affiliates knows or has reason to know that any
         other Termination Event with respect to any Employee Plan has
         occurred, a statement of the chief financial officer of Holdings
         describing such Termination Event and the action, if any, which
         Holdings or such Affiliate proposes to take with respect thereto, (B)
         promptly and in any event within two Business Days after receipt
         thereof by Holdings or any of its Affiliates from the Pension Benefit
         Guaranty Corporation, copies of each notice received by Holdings or
         any of its Affiliates of the Pension Benefit Guaranty Corporation's
         intention to terminate any Plan or to have a trustee appointed to
         administer any Plan, (C) promptly and in any event within thirty (30)
         days after the filing thereof with the Internal Revenue Service,
         copies of each Schedule B (Actuarial Information) to the annual report
         (Form 5500 Series) with respect to each Plan, and (D) promptly and in
         any event within five (5) Business Days after receipt thereof by
         Holdings or any of its Affiliates from a sponsor of a Multiemployer
         Plan or from the Pension Benefit Guaranty Corporation, a copy of each
         notice received by Holdings or any of its Affiliates concerning the
         imposition or amount of withdrawal liability under Section 4202 of
         ERISA in an annual amount in excess of Five Hundred Thousand Dollars
         ($500,000.00), or indicating that such Multiemployer Plan may enter
         reorganization status under Section 4241 of ERISA and that, as a
         result thereof, Holdings or Affiliate's annual contribution
         requirement with respect to such Multiemployer Plan will increase in
         an annual amount exceeding Five Hundred Thousand Dollars
         ($500,000.00);





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 51
<PAGE>   58
                      (x)         promptly after the commencement thereof and
         in any event not later than five (5) Business Days after service of
         process with respect thereto on, or the obtaining of knowledge thereof
         by, Holdings or any of its Restricted Subsidiaries, notice of each
         action, suit or proceeding before any court or other Governmental
         Authority or any arbitrator which may cause a Material Adverse Change;

                      (xi)        promptly after any change in any Person who
         purchases any Hydrocarbons from any Borrower produced from Petroleum
         and Natural Gas Rights which constitute Collateral, the name and
         address of the new purchaser and, if the purchase contract applicable
         to the purchaser extends for a period in excess of six (6) months, a
         letter executed by such purchaser pursuant to which it shall
         acknowledge the Administrative Agent's Lien in the amounts paid by
         such purchaser to Borrowers and agree to pay such amounts to the
         Administrative Agent upon receipt of written notice of default from
         the Administrative Agent.  Upon the request of the Administrative
         Agent, the Borrowers will provide the Administrative Agent with the
         names and address of all purchasers of Hydrocarbons attributable to
         the Petroleum and Natural Gas Rights pledged as Collateral by
         Exploration, Acquisitions and the other Borrowers and such other
         information with respect to such purchasers as the Administrative
         Agent may reasonably request; and

                    (xii)         promptly upon request, such other information
         concerning the Collateral or the condition or operations, financial or
         otherwise, of any Credit Party or any of their respective Subsidiaries
         as the Administrative Agent or any Lender from time to time may
         reasonably request.

                 (e)      Compliance with Laws, Etc.  The Companies will
         comply, and cause each of their respective Subsidiaries to comply,
         with all applicable laws, rules, regulations and orders (including,
         without limitation, Environmental Laws) to the extent the failure to
         so comply therewith would cause a Material Adverse Change, such
         compliance (to the extent required in accordance with the foregoing)
         to include, without limitation, (i) paying before the same become
         delinquent all taxes, assessments and governmental charges or levies
         imposed upon it or upon its income or profits or upon any of its
         properties, and (ii) paying all lawful claims which if unpaid might
         become a Lien or charge upon any of its properties, except to the
         extent contested in good faith by proper proceedings which stay the
         imposition of any penalty, fine or Lien resulting from the non-payment
         thereof and with respect to which adequate reserves have been set
         aside, to the extent required by GAAP, for the payment thereof.

                 (f)      Preservation of Existence, Etc.  Each Company will
         maintain and preserve its existence and any material rights and
         privileges, and cause each of its Subsidiaries to maintain and
         preserve its existence, rights and privileges if the failure of any
         such Subsidiary (other than a Borrower) so to maintain and preserve
         such existence, rights and privileges would cause a Material Adverse
         Change, and become or remain, and cause each of its Subsidiaries to
         become or remain, duly qualified and in good standing in each





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 52
<PAGE>   59
         jurisdiction in which the character of the properties owned or leased
         by it or in which the transaction of its business makes such
         qualification necessary and in which the failure to be so qualified
         would cause a Material Adverse Change.

                 (g)      Maintenance of Properties, Etc.  Each Company will
         maintain and preserve, and cause each of its Subsidiaries to maintain
         and preserve, all of the Collateral and all of its other material
         properties which are necessary or useful in the proper conduct of its
         business in good working order and condition, ordinary wear and tear
         excepted and comply in all material respects and cause each of its
         Subsidiaries to comply in all material respects, at all times with the
         provisions of all leases to which it is a party as lessee or under
         which it occupies property, so as to prevent any loss or forfeiture
         thereof or thereunder if such a loss or forfeiture would cause a
         Material Adverse Change; provided, however, that (i) nothing in this
         subsection (g) shall be deemed (x) to require Holdings or any of its
         Subsidiaries to perpetuate or renew any oil and gas lease or other
         lease by payment of rental or delay rental or by commencement or
         continuation of operations or to prevent Holdings or any of its
         Subsidiaries from abandoning or releasing any oil and gas lease or
         other lease when in any of such events, in the opinion of Holdings or
         the applicable Subsidiary exercised in good faith, it is uneconomic so
         to perpetuate the same or (y) prohibit Holdings or any of its
         Subsidiaries from assigning by customary farmout or farmin agreements,
         oil and gas leases in the ordinary course of business which relate to
         quantities of Hydrocarbons which are not Proven Reserves and (ii) in
         the event of such termination or assignment of any such lease included
         in the Collateral, upon request of Holdings, and at the expense of
         Holdings, the Administrative Agent shall execute and deliver a
         recordable instrument releasing the Liens of the Administrative Agent
         therein to the extent that there has been termination or assignment of
         such lease.

                 (h)      Obtaining of Permits, Etc.  Each Company will obtain,
         maintain and preserve, and cause each of its Subsidiaries to obtain,
         maintain and preserve, all permits, licenses, authorizations,
         approvals and accreditations which are necessary or useful in the
         proper conduct of its business and which the failure to so obtain,
         maintain or preserve, as applicable, would cause a Material Adverse
         Change.

                 (i)      Keeping of Records and Books of Account.  Each
         Company will keep, and cause each of its Subsidiaries to keep,
         adequate records and books of account, with complete entries made in
         accordance with GAAP consistently applied, reflecting all of its
         financial transactions.

                 (j)      Inspection Rights.  Each Company will permit, and
         cause each of its Subsidiaries to permit, the Administrative Agent,
         any Lender or any agents or representatives thereof at any reasonable
         time and from time to time upon reasonable notice to examine and make
         copies of and abstracts from its records and books of account, to
         visit and inspect its properties and to discuss its affairs, finances
         and accounts with any of the directors, officers, employees or other
         representatives thereof; provided, however, that neither Holdings nor
         any of its Subsidiaries shall be required to disclose to the





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 53
<PAGE>   60
         Administrative Agent, any Lender or any agents or representatives
         thereof any information which is the subject of attorney-client
         privilege or attorney's work-product privilege properly asserted by
         the applicable Person to prevent the loss of such privilege in
         connection with such information.

                 (k)      Environmental Laws.  Each Company will (i) provide,
         and cause each of its Subsidiaries to provide, to the Administrative
         Agent promptly following receipt, copies of any notice, pleading,
         citation, indictment, complaint, order, decree or other documentation
         from any source asserting or alleging a material violation of any
         Environmental Law or a circumstance or condition which requires or may
         require a material financial contribution by Holdings or any of its
         Subsidiaries for a Remedial Action under any Environmental Law, or
         which seeks a material amount of damages or civil, criminal or
         punitive penalties from Holdings or any of its Subsidiaries for an
         alleged violation of any Environmental Law, or which names or lists
         Holdings or any of its Subsidiaries as a potentially responsible party
         under any Environmental Law; and (ii) comply, and cause each of its
         Subsidiaries to comply, with any order, decree or similar requirements
         from any Governmental Authority concerning a violation of any
         Environmental Law or a financial contribution by Holdings  or any of
         its Subsidiaries or a cleanup, removal, remedial action or other
         response by or on the part of Holdings or any of its Subsidiaries
         under any Environmental Law, except that compliance shall not be
         required so long as (1) the validity of the same shall be contested in
         good faith and by proper proceedings, (2) the property shall then be
         in no danger of being sold, forfeited or lost pursuant to such
         contest, (3) adequate reserves have been established in accordance
         with GAAP by Holdings or such Subsidiary in connection therewith and
         are maintained for the duration of such contest, (4) the Lien of the
         Security Documents shall then be in no danger of being forfeited or
         subordinated to any Lien or claim, and (5) by reason of such Person's
         action or inaction, neither the Administrative Agent nor any Lender
         shall at any time be subject to any liability by reason of such
         contest or the alleged noncompliance which is the subject of such
         contest.

                 (l)      Environmental Reports and Compliance.  If the Lenders
         determine in good faith that Holdings or any of its Subsidiaries may
         not be operating its properties in accordance with Environmental Laws
         or that the Administrative Agent, Lenders, Holdings, any of its
         Subsidiaries or any Collateral may be subject to any liability or any
         Liens under or in accordance with Environmental Law, the Lenders shall
         have the right to require Holdings to cause to be conducted an
         environmental audit of any portion of such properties at the
         Companies' sole cost and expense, with an independent Person
         satisfactory to the Lenders.  If Holdings shall fail to cause such
         environmental audit to be conducted, the Lenders shall have the right
         to cause such environmental audit to be conducted, at the Companies'
         sole cost and expense, and Holdings and its Subsidiaries shall give
         access to the Administrative Agent and/or its representatives, and
         shall otherwise fully cooperate, with respect to such environmental
         audit.





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 54
<PAGE>   61
                 (m)      Further Assurances; Post Closing Matters; Letters in
         Lieu.  Each Company will execute and deliver, and will cause each of
         its Subsidiaries to execute and deliver, such further documentation as
         may be reasonably requested by any Lender to carry out the provisions
         and purposes of this Agreement and the other Loan Documents and to
         preserve and perfect the Liens of the Administrative Agent in the
         Collateral.  In furtherance of the foregoing, each Company agrees to
         (i) deliver to the Administrative Agent endorsements to the insurance
         policies covering the assets of Acquisitions within thirty (30) days
         of the Closing Date (A) naming the Administrative Agent for the
         benefit of the Lenders as named insured or loss payee thereunder as
         specified by the Administrative Agent and (B) providing that such
         policies may be terminated or cancelled (by the issuer or insured
         thereunder) only upon thirty (30) days prior written notice to the
         Administrative Agent; (ii) deliver within sixty (60) days of the
         Closing Date all certificates of title issued in respect of equipment
         (other than motor vehicles which do not have a material value) pledged
         by any Borrower or any Restricted Subsidiary as Collateral with the
         Administrative Agent's lien noted thereon; and (iii) from time to
         time, provide the Administrative Agent with such additional Letters in
         Lieu of Transfer Orders executed in blank by Exploration and
         Acquisitions as the Administrative Agent may reasonably request.  The
         Letters in Lieu of Transfer Orders delivered pursuant to Section
         5.01(d)(vi) and this Section 7.01(m) may be completed and sent by the
         Administrative Agent to the purchasers of Hydrocarbons attributable to
         the Petroleum and Natural Gas Rights pledged as Collateral by
         Exploration and Acquisitions only upon the occurrence and during a
         continuance of an Event of Default.

                 (n)      Unrestricted Subsidiaries.  Each Company will cause
         each of its Unrestricted Subsidiaries at all times to (i) maintain
         corporate records and books of account and deposit accounts separate
         from those Holdings or any of Holdings' other Subsidiaries; (ii)
         prepare separate consolidated financial statements in accordance with
         Section 7.01(d); and (iii)  observe all formal corporate formalities
         applicable to a separate corporation and otherwise observe all other
         requirements necessary to establish such Subsidiary, with respect to
         all Persons (including all creditors) who deal with such Subsidiary,
         as a separate legal entity.  When any Unrestricted Subsidiary is
         established Holdings will cause, as of such date, (i) the value of
         such Unrestricted Subsidiary's assets to be greater than its debt and
         other obligations (including contingent obligations) and (ii) such
         Unrestricted Subsidiary to have sufficient capital to operate its
         business as proposed to be conducted and sufficient anticipated cash
         flow to be able to pay its obligations as they become due.

                 (o)      Value of Mortgaged Properties.     The Proven
         Reserves attributable to the Mortgaged Property constitute at least
         seventy-five percent (75%) of the value of all Proven Reserves
         attributable to all Borrowers' Petroleum and Natural Gas Rights.

         SECTION 7.02.  Negative Covenants.  So long as any of the Obligations
shall remain unpaid or any Lender has any Commitment hereunder, no Company
will, without the prior written consent of the Required Lenders:





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 55
<PAGE>   62
         (a)     Liens, Etc.  Create or suffer to exist, or permit any of its
Restricted Subsidiaries to create or suffer to exist, any Lien upon or with
respect to any of its properties, rights or other assets, whether now owned or
hereafter acquired, or assign or otherwise transfer as collateral security, or
permit any of its Restricted Subsidiaries to assign or otherwise transfer as
collateral security, any right to receive income, other than:

                      (i)         Liens created pursuant to the Loan Documents
         or otherwise created in favor of the Administrative Agent;

                      (ii)        Liens existing on the date hereof, as set
         forth in Schedule 7.02(a) hereto and any renewals or extensions
         thereof, or replacements therefor, but not the extension of coverage
         thereof to other property or the increase in the principal amount
         secured thereby;

                    (iii)         (A) purchase money Liens in property acquired
         or held by Holdings or any of its Restricted Subsidiaries in the
         ordinary course of its business to secure the purchase price of such
         property or Indebtedness for borrowed money incurred solely for the
         purpose of financing or refinancing the acquisition of such property
         and any renewals or extensions thereof, or replacements therefor, (B)
         Liens existing on such property at the time of its acquisition
         securing Indebtedness for borrowed money permitted by Section 7.02(b)
         and any renewals or extensions thereof, or replacements therefor or
         (C) Liens arising in connection with Capitalized Lease Obligations on
         property leased by Holdings or any of its Restricted Subsidiaries in
         the ordinary course of its business to secure such Capitalized Lease
         Obligations; provided in the case of Liens referred to in clauses (A),
         (B) and (C) above (including the renewals, extensions and replacements
         thereof) that (1) no such Lien shall extend to or cover any property
         of Holdings or any of its Restricted Subsidiaries other than the
         property so acquired or leased, as applicable, and improvements
         thereon, and (2) the principal amount of the Indebtedness secured by
         any such Lien shall not (x) exceed the fair market value of such
         property at the time of the acquisition or lease, as applicable,
         thereof or (y) increase in connection with any renewal, extension or
         replacement;

                      (iv)        Liens for taxes, assessments or governmental
         charges or levies to the extent that the payment thereof shall not be
         required by Section 7.01(e) hereof;

                      (v)         Liens created by operation of law, including
         but without limitation, carrier's liens, warehousemen's liens,
         landlord's liens, materialmen's liens, mechanics' liens and other
         similar liens, arising in the ordinary course of business and securing
         claims the payment of which shall not be required by Section
         7.01(e)hereof;

                      (vi)        deposits, pledges or liens (other than liens
         arising under ERISA) securing (A) obligations incurred in respect of
         workers' compensation, unemployment insurance or other forms of
         governmental insurance or benefits, (B) the performance of bids,
         tenders, leases, contracts (other than for the payment of money) and
         statutory obligations, or (C) obligations on surety or appeal bonds,
         but only to the extent such deposits, pledges or liens are incurred or
         otherwise arise in the ordinary course of business and secure
         obligations which are not past due;





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 56
<PAGE>   63
                    (vii)         easements, rights-of-way, covenants,
         restrictions and other similar encumbrances incurred in the ordinary
         course of business and encumbrances consisting of zoning restrictions,
         easements, licenses and other restrictions on the use of real property
         and minor irregularities in the title thereto which do not (A) secure
         obligations for the payment of money or (B) materially impair the
         value of such property or its use by Holdings or any of its Restricted
         Subsidiaries in the normal conduct of such Person's business;

                   (viii)         royalties, overriding royalties, revenue
         interests, net revenue interests, production payments (other than
         production payments granted or created by Holdings or its Restricted
         Subsidiaries in connection with the borrowing of money), advance
         payment obligations (other than obligations in respect of advance
         payments received by Holdings in connection with the borrowing of
         money) and other similar burdens incurred in the ordinary course of
         business and (a) now existing with respect to the Collateral (provided
         they do not increase the Working Interests or decrease the net revenue
         interests applicable to the Collateral from that as reflected on the
         Initial Engineering Report or the ING Reserve Report (as defined in
         the ING Acquisition Agreement) or any oil, gas or mineral leases or
         other interests or (b) hereafter created on oil, gas or mineral leases
         or other interests which do not constitute Collateral and which are
         now owned or hereafter acquired by or any of its Restricted
         Subsidiaries;

                      (ix)        Liens that are permitted by the Security
         Documents;

                      (x)         Liens on property of any corporation that
         becomes a Subsidiary of Holdings after the date of this Agreement,
         provided that such Liens are in existence at the time such corporation
         becomes a Subsidiary of Holdings and were not created in anticipation
         thereof;

                      (xi)        with respect to any property from which
         Hydrocarbons may be severed or extracted in commercial quantities,
         liens for farmout, farmin, joint operating, and area of mutual
         interest agreements and/or similar arrangements that Holdings or the
         applicable Restricted Subsidiary determines in good faith to be
         necessary for the economic development of such property and are
         customary and usual for the area in which such property is located;
         provided, however, that with respect to any such Liens created
         subsequent to the date hereof on property which constitutes
         Collateral, such Liens shall be expressly made subordinate to the
         Liens created by the Security Documents;

                    (xii)         rights reserved to or vested in any
         municipality or other Governmental Authority by the terms of any
         right, power, franchise, grant, license or permit, or by any provision
         of law, to terminate such right, power, franchise, grant, license or
         permit or to purchase, condemn, expropriate or recapture, or to
         designate a purchaser of, any of the property of Holdings or of any of
         its Restricted Subsidiaries;

                   (xiii)         rights reserved to or vested in any
         municipality or other Governmental Authority to control or regulate
         any property of Holdings or of any of its Restricted Subsidiaries, or
         to use such property in a manner which does not materially impair the
         use





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 57
<PAGE>   64
         of such property for the purposes for which it is held by Holdings or
         any such Restricted Subsidiary;

                    (xiv)         any obligations or duties affecting the
         property of Holdings or of any of its Restricted Subsidiaries to any
         municipality or other Governmental Authority with respect to any
         franchise, grant, license or permit;

                      (xv)        rights under common law of a common owner of
         any interest in real estate, right of way or easement held by Holdings
         or any of its Restricted Subsidiaries and such common owner as tenants
         in common or through other common ownership;

                    (xvi)         rights of set-off or banker's liens created
         by law in favor of commercial banks;

                   (xvii)         Liens encumbering cash and cash equivalents
         securing Indebtedness permitted by subsection 7.02(b)(x);

                   (xviii)        Liens granted by Coho Shell to any Borrower
         to secure Permitted Coho Shell Advances; and

                    (xix)         Liens granted by any Intercompany Borrower to
         any Borrower to secure Permitted Intercompany Advances.

         (b)     Indebtedness.  Create, incur or suffer to exist, or permit any
Restricted Subsidiaries to create, incur or suffer to exist, any Indebtedness,
other than:

                       (i)        Indebtedness evidenced or created hereunder
         or under the other Loan Documents and any renewals and extensions
         thereof;

                      (ii)        Permitted Coho Shell Advances;

                     (iii)        Permitted Intercompany Advances;

                      (iv)        Indebtedness reflected on the Financial
         Statements or on Schedule 6.01(m) hereto and any renewals and
         extensions thereof but without any increase in the principal amount
         thereof;

                       (v)        Indebtedness incurred if neither Holdings nor
         any of its Restricted Subsidiaries has any personal liability for the
         repayment thereof and any renewals and extension thereof;

                      (vi)        Guaranties by indorsement of negotiable
         instruments for deposit or collection in the ordinary course of
         business;





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 58
<PAGE>   65
                     (vii)        The Subordinated Indebtedness and, subject to
         the prior written approval of the Required Lenders, indebtedness of
         Holdings or any of its Restricted Subsidiaries and any renewals and
         extensions thereof if payment of such Indebtedness and any Liens
         securing the payment thereof are fully subordinated to the Obligations
         (including, without limitation, with respect to each Credit Party, its
         obligations, if any, under the Guaranty or a Subsidiary Guaranty) and
         the Liens of the Administrative Agent in the Collateral and, with
         respect to Coho Shell and any Intercompany Borrower, are fully
         subordinated to the obligations to repay the Permitted Coho Shell
         Advances and the Permitted Intercompany Advances, as the case may be,
         and the Liens securing payment thereof;

                    (viii)        liabilities in an aggregate amount less than
         Five Hundred Thousand Dollars ($500,000.00) incurred under Title IV of
         ERISA with respect to any Plan (other than a Multiemployer Plan)
         covered by Title IV of ERISA and withdrawal liability incurred under
         ERISA in an amount not at any time exceeding Five Hundred Thousand
         Dollars ($500,000.00);

                      (ix)        Indebtedness in any fiscal year not to exceed
         an aggregate amount of $20,000,000 (including Capitalized Lease
         Obligations) secured by purchase money Liens permitted by Section
         7.02(a)(iii) and any renewals or extension thereof provided there is
         no increase in the principal amount thereof;

                       (x)        Capitalized Lease Obligations incurred in
         accordance with the limitations imposed by Section 7.02(a)(iii);

                      (xi)        Indebtedness arising in connection with
         letters of credit issued for the account of Holdings or any of its
         Restricted Subsidiaries to secure (A) obligations incurred in respect
         of workers' compensation, unemployment insurance or other forms of
         governmental insurance or benefits, (B) the performance of bids,
         tenders, leases, contracts (other than for the payment of money) and
         statutory obligations, or (C) obligations on surety or appeal bonds
         but only to the extent that (x) such obligations, bids, tenders,
         leases, contracts, statutory obligation or obligations on surety and
         appeal bonds are incurred or otherwise arise in the ordinary course of
         business; (y) no letter of credit issued under the permission of this
         subsection 7.02(b)(x)(i) shall have an original face amount in excess
         of One Hundred Thousand Dollars ($100,000.00) and (z) the Indebtedness
         of any Borrower arising in connection of each letter of credit issued
         under the permission of this subsection 7.02(b)(x)(i) shall be secured
         in full by cash or cash equivalent collateral; and

                     (xii)        Indebtedness (and any renewals and extensions
         thereof) owed to Holdings or a Restricted Subsidiary of Holdings
         arising as a result of an Investment made by Holdings or such
         Restricted Subsidiary in the obligor of such Indebtedness that is not
         prohibited by Section 7.02(g), if (A) in the case of Indebtedness
         incurred by any Credit Party, the payment of such Indebtedness and any
         renewals and extensions thereof and any Liens securing the payment
         thereof are fully subordinated to the Obligations (including, without
         limitation, with respect to each Credit Party, its obligations, if
         any, under the Guaranty or a





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 59
<PAGE>   66
         Subsidiary Guaranty) and the Liens of the Administrative Agent in the
         Collateral and (B) in the case of Indebtedness incurred by Coho Shell
         or any Intercompany Borrower, the payment of such Indebtedness and any
         renewals and extensions thereof and any Liens securing the payment
         thereof are fully subordinated to the obligations of Coho Shell or
         such Intercompany Borrower to repay the Permitted Coho Shell Advances
         or the Permitted Intercompany Advances, as the case may be, and the
         Liens securing payment thereof, all upon terms and provisions
         reasonably acceptable to the Lenders.

         (c)     Merger, Consolidation.  Merge into or consolidate with any
Person or permit any Restricted Subsidiaries to merge into or consolidate with
any Person except as permitted by Section 7.01(f) or unless the proposed merger
or consolidation will not negatively affect the financial condition or
otherwise impair the creditworthiness of either Company.

         (d)     Sale of Assets, Etc.  Sell, assign, lease or otherwise
transfer or dispose of, or permit any of its Restricted Subsidiaries to sell,
assign, lease or otherwise transfer or dispose of, whether in one transaction
or in a series of related transactions, any of its properties, rights or other
assets (whether now owned or hereafter acquired) to any Person except for sales
and other dispositions by Holdings and its Restricted Subsidiaries of inventory
and assets (other than Petroleum and Natural Gas Rights to which Proven
Reserves are attributable) in the ordinary course of business, including, but
without limitation, routine farmouts by Holding and its Subsidiaries in
connection with quantities of Hydrocarbons which are not Proven Reserves;
provided, however, that

                       (i)        nothing in this subsection (d) shall be
         deemed to prohibit Holdings or any of its Restricted Subsidiaries from
         making assignments of oil and gas leases pursuant to the provisions of
         clause (i) (y) of subsection (g) of Section 7.01 hereof;

                      (ii)        Holdings and its Restricted Subsidiaries may
         sell, assign, lease or otherwise transfer or dispose of, in bona fide
         arm's length transactions any of their properties, rights and other
         assets that do not constitute Collateral; and

                     (iii)        A Borrower may sell, assign, lease or
         otherwise transfer or dispose of, in a bona fide arms' length
         transaction, one or more portions of the Petroleum and Natural Gas
         Rights constituting Collateral (and the Administrative Agent, at
         Borrowers' expense, shall execute and deliver a recordable instrument
         releasing the Liens of the Administrative Agent therein) so long as:

                                  (1)      when any such sale or sales of
                          assets included in determining the Borrowing Base in
                          any calendar year yield aggregate net after-tax
                          proceeds in excess of $5,000,000, and on any sale
                          thereafter during such calendar year, the outstanding
                          Advances shall be prepaid on the date of the sale,
                          assignment, lease, transfer or other disposition
                          which causes the aggregate of such proceeds to exceed
                          $5,000,000, and on the date of any subsequent sale
                          during that calendar year, by an amount equal to the
                          greater of (A) one hundred twenty percent (120%) of
                          the Borrowing Base valuation of the Collateral so
                          disposed of (as reasonably determined by the Lenders)
                          or





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 60
<PAGE>   67
                          (B) seventy percent (70%) of the net price paid to
                          the applicable Borrower in connection with such
                          disposition, such prepayment to be applied as a
                          mandatory prepayment in accordance with Section
                          3.02(b); and

                                  (2)      no Event of Default or Potential
                          Default exists or would result therefrom; and

                                  (3)      after giving effect to such
                          disposition and the redetermination of the Borrowing
                          Base in accordance with Section 2.10(e), the value of
                          the Borrowers' Proven Producing Reserves included as
                          Collateral shall constitute an amount not less than
                          seventy percent (70%) of the total Borrowing Base, as
                          determined by the Lenders.

         Prior to the disposition of any Collateral in accordance with this
subsection 7.02(d)(iii) and upon the request of Borrowers, the Administrative
Agent and the Lenders shall provide the Borrowers information regarding the
Borrowing Base value being considered by the Lenders for the purposes of this
subsection 7.02(d)(iii) and with respect to the Collateral in question.

         (e)     Change in Nature of Business.  Engage in any business other
than the exploration for, and the production, transportation, storage and sale
of, Hydrocarbons and related products and other activities necessary or useful
to facilitate the profitable enhancement of Hydrocarbon value.

         (f)     Transactions with Affiliates.  Enter into contracts,
agreements, undertakings or transactions with Affiliates of the Companies,
other than contracts, agreements, undertakings or transactions which (i) are
described on Schedule 7.02(f) hereto, or (ii) (A) are at a price and on other
terms which are not less favorable than those which could be obtained from
qualified third parties in arms' length transactions, (B) are set forth in
written agreements and (C) are for the provisions of necessary services;
provided, however, that nothing in this subsection (f) shall prohibit any
Company from declaring or paying any dividends or other distributions to
shareholders in respect of Capital Stock to the extent that any such
declaration or payment otherwise complies with this Agreement and applicable
law.

         (g)     Restricted Payments and Restricted Investments.  Make any
Restricted Payment or Restricted Investment or permit any of its Restricted
Subsidiaries to make any Restricted Payment or Restricted Investment; provided,
however, that Holdings or any Restricted Subsidiary may make a Restricted
Payment or a Restricted Investment if, immediately after giving effect to such
Restricted Payment or Restricted Investment, (a) no Event of Default or
Potential Default shall exist or result therefrom and (b)(i) the sum of the
aggregate amount of Restricted Payments and Restricted Investments made by the
Borrowers and their Restricted Subsidiaries since the Original Closing Date and
made since February 8, 1994 by Holdings and any of its Restricted Subsidiaries
which were not Restricted Subsidiaries as of the Original Closing Date and the
amount of such proposed Restricted Payment or Restricted Investment would not
exceed an amount equal to 50% of Borrowers' Consolidated Net Income for the
entire period from and including January 1, 1992 to the date of making such
proposed Restricted Payment or Restricted Investment, plus, in the case of any
proposed Investment in a Subsidiary of Holdings, an aggregate amount not to
exceed Two Million





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 61
<PAGE>   68
         Five Hundred Thousand Dollars ($2,500,000.00), or (ii) the ratio of
         Borrowers' Consolidated Indebtedness to Borrowers' Stockholders'
         Equity would not exceed 1.6 to 1 after giving effect to such proposed
         Restricted Payment or Restricted Investment or (iii) the sum of the
         aggregate amount of Restricted Payments and Restricted Investments
         made by the Borrowers and their Restricted Subsidiaries since the
         Original Closing Date and made since February 8, 1994 by  Holdings and
         any of its Restricted Subsidiaries which were not Restricted
         Subsidiaries as of the Original Closing Date and the amount of the
         proposed Restricted Payment or Restricted Investment would not exceed
         an amount equal to one hundred percent (100%) of Borrowers'
         Consolidated Net Income for the three fiscal years immediately
         preceding the date of making such proposed Restricted Payment or
         Restricted Investment, plus, in the case of any proposed Investment in
         a Subsidiary of Holdings, an aggregate amount equal to Two Million
         Five Hundred Thousand Dollars ($2,500,000.00).  Notwithstanding the
         foregoing, Borrowers will not make any advance, loan or extension of
         credit to Coho Shell or any Intercompany Borrower out of proceeds of
         Advances unless such advance, loan or extension of credit would
         constitute a Permitted Coho Shell Advance or a Permitted Intercompany
         Advance.  No Company shall consent to or approve the issuance of any
         additional share of any class of Capital Stock of any Borrower or Coho
         Canada or any securities convertible into, or exchangeable for, any
         such shares or any warrants, options, rights, or other commitments
         entitling any Person to purchase or otherwise acquire any such shares.

         (h)     Financial Covenants.  Notwithstanding anything to the contrary
otherwise set forth in this Agreement, (i) create or incur any Indebtedness or
obligations as lessee, (ii) sell or transfer any assets, (iii) make any
investments or capital expenditures, (iv) make any Restricted Payment, (v)
engage in any other act or transaction or (vi) permit any of its Subsidiaries
to do any of the forgoing if, after giving effect thereto, any of the financial
covenants set forth in Section 7.01 hereof would be violated thereby.

         (i)     Hedging.  The Borrowers will not enter into Hedging
Arrangements with respect to more than seventy-five percent (75%) of their
Daily Production of Crude Oil or their Daily Production of Natural Gas.

         SECTION 7.03  Post-Closing Date Obligations.  Within thirty (30) days
after the Closing Date (unless a longer period is specified below), Borrowers
shall deliver to the Administrative Agent all of the following, in form and
substance satisfactory to the Co-Documentation Agents and each Lender:

                [(a)      Foreign Qualification.  Certificates as to
         Acquisitions' good standing and due qualification to do business,
         issued by the appropriate officials in Oklahoma and Texas;]

                 (b)      Opinion of Local Counsel.  Favorable opinion of local
         counsel to the Borrowers in Oklahoma as to the matters set forth in
         Exhibit D hereto, and such other matters as the Administrative Agent
         may reasonably request;

                 (c)      Title Matters.  Within one hundred fifty (150) days
         after the Closing Date, favorable title opinions and/or title reports
         addressed to the Administrative Agent and issued by counsel to the
         Borrowers that is experienced in the examination of title to Petroleum
         and





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 62
<PAGE>   69
         Natural Gas Rights as to the status of Acquisitions' title to and
         Liens affecting the Amoco Properties containing at least seventy-five
         percent (75%) of the Proven Reserves attributable to the Amoco
         Properties;

                 (d)      Environmental Matters.  Within two hundred seventy
         (270) days after the Closing Date, a report or reports, in form, scope
         and detail satisfactory to the Administrative Agent, from
         environmental engineering firms acceptable to the Administrative
         Agent, setting forth the results of the Phase I environmental review
         of the Amoco Properties, which reports shall (i) cover at least
         seventy-five percent (75%) of the Proven Reserves attributable to the
         Amoco Properties and (ii) not reflect the existence of facts or
         circumstances which would constitute a violation(s) of applicable
         Environmental Law which are likely to result in a Material Adverse
         Change or in a material liability to a Credit Party;

                 (e)      Notices/Correspondence pursuant to the Amoco Purchase
         Agreement.  Copies of all notices or other correspondence or
         transmittals between Amoco Production Company and Acquisitions
         pursuant to the Amoco Purchase Agreement, as soon as practical after
         they have been sent or received, as the case may be, by Acquisitions;

                 (f)      Lien Searches.  Within sixty (60) days after the
         Closing Date, the results of Uniform Commercial Code and other Lien
         searches showing all financing statements and other Lien instruments
         filed against Acquisitions or the Amoco Properties in such public
         offices as may be identified by the Administrative Agent;

                 (g)      Recording.  Within forty-five (45) days after the
         Closing Date, an opinion or opinions addressed to the Administrative
         Agent and issued by counsel to the Borrowers experienced in examining
         title to Petroleum and Natural Gas Rights, (i) certifying the due and
         proper recording in the appropriate county records and in the
         appropriate Bureau of Land Management (where applicable) of the
         assignments, deeds and other conveyances to Acquisitions in connection
         with the transactions contemplated by the Amoco Purchase Agreement of
         interests in and to the properties covered by the Oklahoma Mortgage
         which are set out in Exhibit A to the Oklahoma Mortgage; and (ii)
         certifying the due and proper recording of the Oklahoma Mortgages in
         each county and in each office of the Bureau of Land Management (where
         applicable) required to perfect the Liens of the Lenders under the
         terms of the Oklahoma Mortgage;

                 (h)      Additional Governmental Certificates.  Within thirty
         (30) days after the Closing Date, all certificates contemplated by
         Section 5.01(e)(vii) which the Administrative Agent does not require
         to be delivered on the Closing Date; and

                 (i)      Additional Documentation.  The Administrative Agent
         shall have received such additional approvals, opinions, title
         opinions, or documents as the Administrative Agent or its legal
         counsel may reasonably request.

A failure of Borrowers to timely comply with its obligations under this Section
7.03 shall not constitute a Default or prevent borrowing under this Agreement,
but instead shall constitute a basis





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 63
<PAGE>   70

for not including the affected Properties in the Borrowing Base and be subject
to the requirements of Section 3.02(b).

                                  ARTICLE VIII

                               EVENTS OF DEFAULT

         SECTION 8.01.  Events of Default.  Each of the following shall be
deemed an "Event of Default":

                 (a)      Any Borrower shall fail to pay any principal of any
         Note when due (whether by scheduled maturity, required prepayment,
         acceleration, demand or otherwise); or

                 (b)      Any Borrower shall fail to pay any interest on any
         Note when due (whether by scheduled maturity, required prepayment,
         acceleration, demand or otherwise) or any Borrower or Holdings shall
         fail to pay any other Obligation and such default shall continue for
         more than five (5) days; or

                 (c)      Any representation, warranty or certification made by
         any Credit Party under or in connection with any Loan Document shall
         have been incorrect in any material respect when made; or

                 (d)      Any Credit Party shall fail to perform or observe any
         covenant or agreement contained in any Loan Document (except the
         covenants and agreements described in subsections (a) and (b) of this
         Section 8.01, or set forth in subsections (b), (d) (vii), (f) and (j)
         of Section 7.01 and the entire Section 7.02) and such failure, if
         capable of being remedied, shall remain unremedied for thirty (30)
         days after written notice thereof shall have been given to such Credit
         Party by the Administrative Agent; or any Credit Party shall fail to
         perform or observe any covenant or agreement contained in subsections
         (b), (d) (vii), (f) and (j) of Section 7.01 or contained in Section
         7.02; provided, however, a breach of the covenants contained in
         Section 7.03 shall not be an Event of Default but shall have the
         consequences provided at the end of such Section, including being
         subject to the provisions of Section 3.02(b).

                 (e)      Any Credit Party shall fail to pay any of its
         Indebtedness (excluding (i) Indebtedness evidenced by the Notes and
         (ii) Indebtedness consisting of accounts payable incurred in the
         ordinary course of business to the extent contested in good faith by
         proper proceedings and where an adverse determination thereof will not
         cause a Material Adverse Change in excess of Five Hundred Thousand
         ($500,000.00)), or any interest or premium thereon, when due (whether
         by scheduled maturity, required prepayment, acceleration, demand or
         otherwise) and such failure shall continue after the applicable grace
         period, if any, specified in the agreement or instrument relating to
         such Indebtedness; or any other default under any agreement or
         instrument relating to any such Indebtedness, or any other event,
         shall occur and shall continue after the applicable grace period, if
         any, specified in such agreement or instrument, if the effect of such
         default or event is to accelerate, or to permit





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 64
<PAGE>   71
         the acceleration of, the maturity of such Indebtedness; or any such
         Indebtedness in excess of such amount shall be declared to be due and
         payable, or required to be prepaid (other than by a regularly
         scheduled required prepayment), prior to the stated maturity thereof;
         or

                 (f)      Any Credit Party shall be generally not paying its
         debts as such debts become due, or shall admit in writing its
         inability to pay its debts generally, or shall make a general
         assignment for the benefit of creditors; or any proceeding shall be
         instituted by any Credit Party seeking to adjudicate it a bankrupt or
         insolvent, or seeking dissolution, liquidation, winding-up,
         reorganization, arrangement, adjustment, protection, relief or
         composition of it or its debts under any law relating to bankruptcy,
         insolvency or reorganization or relief of debtors, or seeking the
         entry of an order for relief or the appointment of a receiver,
         trustee, custodian or other similar official for any Credit Party or
         for any substantial part of its property; or any Credit Party shall
         take any action to authorize or effect any of the actions set forth
         above in this subsection (f); or any proceeding shall be instituted
         against any Credit Party seeking to adjudicate such Credit Party a
         bankrupt or insolvent, or seeking dissolution, liquidation,
         winding-up, reorganization, arrangement, adjustment, protection,
         relief or composition of such Credit Party or its debts under any law
         relating to bankruptcy, insolvency or reorganization or relief of
         debtors, or seeking the entry of an order for relief or the
         appointment of a receiver, trustee, custodian or other similar
         official for such Credit Party or for any substantial part of its
         property and such proceeding shall not be dismissed within sixty (60)
         days of the institution thereof; or

                 (g)      Any material provision of any Loan Document shall at
         any time for any reason be declared to be null and void, or the
         validity or enforceability of any provision of any Loan Document shall
         be contested by any Credit Party, or a proceeding shall be commenced
         by any Credit Party seeking to establish the invalidity or
         unenforceability of any provision of any Loan Document, or a
         proceeding shall be commenced by any Governmental Authority or other
         regulatory body having jurisdiction over any Credit Party, seeking to
         establish the invalidity or unenforceability of any material provision
         of any Loan Document, or any Credit Party shall deny that it has any
         liability or obligation purported to be created under any Loan
         Document; or

                 (h)      Any Security Document, after delivery thereof,
         pursuant hereto or pursuant to any other Loan Document, shall for any
         reason, fail or cease to create a valid and perfected and, except to
         the extent permitted by the terms hereof or thereof, first priority
         Lien on any Collateral purported to be covered thereby; or

                 (i)      One or more judgments or orders for the payment of
         money exceeding any applicable insurance coverage by more than Five
         Million Dollars ($5,000,000.00) in the aggregate shall be rendered
         against any Credit Party, and either (i) enforcement proceedings shall
         have been commenced by any creditor upon any such judgment or order,
         or (ii) there shall be any period of thirty (30) consecutive days
         during which a stay of enforcement of any such judgment or order, by
         reason of a pending appeal or otherwise, shall not be in effect; or





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 65
<PAGE>   72
                 (j)      Holdings or any of its Affiliates shall have made a
         complete or partial withdrawal from a Multiemployer Plan, and, as a
         result of such complete or partial withdrawal, Holdings or such
         Affiliate incurs a withdrawal liability in an annual amount exceeding
         Five Hundred Thousand Dollars ($500,000.00) or a Multiemployer Plan
         enters reorganization status under Section 42 of ERISA, and, as a
         result thereof, Holdings' or such Affiliate's annual contribution
         requirement with respect to such Multiemployer Plan increases in an
         annual amount exceeding Five Hundred Thousand Dollars ($500,000.00);
         or

                 (k)      Any Termination Event with respect to any Employee
         Plan shall have occurred, and, thirty (30) days after notice thereof
         shall have been given to Holdings by the Administrative Agent, (i)
         such Termination Event (if correctable) shall not have been corrected,
         and (ii) the then current value of such Employee Plan's vested
         benefits exceeds the then current value of assets allocable to such
         benefits in such Employee Plan by more than Five Hundred Thousand
         Dollars ($500,000.00) (or in the case of a Termination Event involving
         the withdrawal of a "substantial employer" as defined in Section
         4001(a)(2) of ERISA or the withdrawal of an employer treated as a
         "substantial employer" under Section 4062(e) of ERISA, the withdrawing
         employer's proportionate share of such excess shall exceed such
         amount); or

                 (l)      A "default" (as defined in Section 4.01 of the
         Mortgage or as set forth in any other Security Document) shall occur
         and be continuing; or

                 (m)      The occurrence of a Change of Control; or

                 (n)      (i)  An "Event of Default" (as defined in the
         Indenture) shall occur under the Indenture, the Securities, the
         Subsidiary Guaranties or any other documents executed in connection
         therewith, (ii) the Indenture, the Securities, the Subsidiary
         Guaranties or any other documents executed in connection therewith
         shall be amended or modified without the consent of Required Lenders,
         or (iii) the Companies shall fail to notify the Administrative Agent
         and the Co-Documentation Agents of a Default under the Indenture, the
         Securities or the Subsidiary Guaranties or any other documents
         executed in connection therewith within five (5) days after any
         Company becomes aware of the occurrence of such Default.

         SECTION 8.02. Remedies.  If any Event of Default shall occur and be
continuing, the Administrative Agent, if requested by Majority Lenders, may
(and if directed by Required Lenders, shall) do any one or more of the
following:

                 (a)      Acceleration.  Declare, by written notice to the
         Borrowers, all outstanding principal of and all accrued and unpaid
         interest on the Notes and all other obligations of the Credit Parties
         under the Loan Documents immediately due and payable, and the same
         shall thereupon become immediately due and payable, without notice,
         demand, presentment, notice of dishonor, notice of acceleration,
         notice of intent to accelerate, protest, or other formalities of any
         kind, all of which are hereby expressly waived by each Company.





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 66
<PAGE>   73
                 (b)      Termination of Commitments.  Terminate the
         Commitments without notice to any Credit Party.

                 (c)      Judgment.  Reduce any claim to judgment.

                 (d)      Foreclosure.  Foreclose or otherwise enforce any Lien
         granted to the Administrative Agent for the benefit of the Lenders to
         secure payment and performance of the Obligations in accordance with
         the terms of the Loan Documents.

                 (e)      Rights.  Exercise any and all rights and remedies
         afforded by the laws of the State of New York or any other
         jurisdiction, by any of the Loan Documents, by equity, or otherwise.

Provided, however, that upon the occurrence of an Event of Default under
subsection (f) of Section 8.01, the Commitments of all of the Lenders shall
automatically terminate, and the outstanding principal of and accrued and
unpaid interest on the Notes and all other obligations of the Credit Parties
under the Loan Documents shall thereupon become immediately due and payable
without notice, demand, presentment, notice of dishonor, notice of
acceleration, notice of intent to accelerate, protest, or other formalities of
any kind, all of which are hereby expressly waived by each Company.

         SECTION 8.03.  Performance by the Administrative Agent.  If any Credit
Party shall fail to perform any covenant, duty, or agreement in accordance with
the terms of the Loan Documents, the Administrative Agent may, at the direction
of Required Lenders, and after notice in writing to Borrowers, perform or
attempt to perform, such covenant, duty, or agreement on behalf of such Credit
Party.  In such event, Borrowers shall, at the request of the Administrative
Agent, promptly jointly and severally pay any amount expended by the
Administrative Agent or the Lenders in such performance or attempted
performance to the Administrative Agent at the Principal Office, together with
interest thereon at the Default Rate from the date of such expenditure until
paid.  Notwithstanding the foregoing, it is expressly agreed that neither the
Administrative Agent nor any Lender shall have any liability or responsibility
for the performance of any obligation of any Credit Party under this Agreement
or any of the other Loan Documents.

                                   ARTICLE IX

            THE ADMINISTRATIVE AGENT AND THE CO-DOCUMENTATION AGENTS

         SECTION 9.01.  Appointment, Powers and Immunities of Co-Document
Agents.  In order to expedite the various transactions contemplated by this
Agreement, the Lenders hereby irrevocably appoint (and confirm their prior
appointment pursuant to the Original Credit Agreement and the First Amended
Credit Agreement, the Second Amended Credit Agreement, and the Third Amended
Credit Agreement) and authorize Paribas to act as their Administrative Agent
hereunder and under each of the other Loan Documents.  Paribas consents to such
appointment and agrees to perform the duties of the Administrative Agent as
specified herein.  The Lenders authorize and direct the Administrative Agent to
take such action in their name and on their behalf under the terms and
provisions of the Loan Documents and to exercise such rights and powers
thereunder as are





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 67
<PAGE>   74
specifically delegated to or required of the Administrative Agent for the
Lenders, together with such rights and powers as are reasonably incidental
thereto.  Each Lender hereby irrevocably appoints and authorizes Bank One and
MeesPierson to act as Co-Documentation Agents under this Agreement and the
other Loan Documents.  Except as expressly set out herein and unless otherwise
agreed by the Administrative Agent and the Lenders, the Co-Documentation Agents
shall have no obligations or duties other than those of a Lender hereunder.
The Administrative Agent is hereby expressly authorized to act as the
Administrative Agent on behalf of itself and the other Lenders:

         (a)     To receive on behalf of each of the Lenders any payment of
principal, interest, fees or other amounts paid pursuant to this Agreement and
the Notes and to distribute to each Lender its Pro Rata share of all payments
so received as provided in this Agreement;

         (b)     To receive all documents and items to be furnished under the
Loan Documents;

         (c)     To act as nominee for and on behalf of the Lenders in and
under the Loan Documents;

         (d)     To arrange for the means whereby the funds of the Lenders are
to be made available to Borrowers;

         (e)     To distribute to the Lenders information, requests, notices,
payments, prepayments, documents and other items received from any Credit Party
and other Persons;

         (f)     To execute and deliver to any Credit Party and other Persons,
all requests, demands, approvals, notices, and consents received from the
Lenders;

         (g)     To the extent permitted by the Loan Documents, to exercise on
behalf of each Lender all rights and remedies of Lenders upon the occurrence of
any Event of Default;

         (h)     To accept, execute, and deliver the Security Agreement and any
other Security Documents as the secured party or beneficiary; and

         (i)     To take such other actions as may be requested by Required
Lenders.

         Neither the Administrative Agent, any Co-Documentation Agent nor any
of their Affiliates, officers, directors, employees, attorneys, or agents shall
be liable for any action taken or omitted to be taken by any of them hereunder
or otherwise in connection with this Agreement or any of the other Loan
Documents or Related Transactions Documents except for its or their own gross
negligence or willful misconduct.  Without limiting the generality of the
preceding sentence, the Administrative Agent (i) may treat the payee of any
Note as the holder thereof until the Administrative Agent receives written
notice of the assignment or transfer thereof signed by such payee and in form
satisfactory to the Administrative Agent; (ii) shall have no duties or
responsibilities except those expressly set forth in this Agreement and the
other Loan Documents, and shall not by reason of this Agreement or any other
Loan Document be a trustee or fiduciary for any Lender; (iii) shall not be
required to initiate any litigation or collection proceedings hereunder or
under any other Loan Document except to the extent requested by Required
Lenders; (iv) shall





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 68
<PAGE>   75
not be responsible to the Lenders for any recitals, statements, representations
or warranties contained in this Agreement or any other Loan Documents or
Related Transactions Document, or any certificate or other document referred to
or provided for in, or received by any of them under this Agreement or any
other Loan Document or Related Transaction Document , or for the value,
validity, effectiveness, enforceability or sufficiency of this Agreement or any
other Loan Document or Related Transactions Document  or any other document
referred to or provided for herein or therein or for any failure by any Person
to perform any of its obligations hereunder or thereunder; (v) may consult with
legal counsel (including counsel for the Credit Parties), independent public
accountants, and other experts selected by it and shall not be liable for any
action taken or omitted to be taken in good faith by it in accordance with the
advice of such counsel, accountants, or experts; and (vi) shall incur no
liability under or in respect of any Loan Documents or Related Transactions
Document  by acting upon any notice, consent, certificate, or other instrument
or writing believed by it to be genuine and signed or sent by the proper party
or parties.  As to any matters not expressly provided for by this Agreement,
the Administrative Agent shall in all cases be fully protected in acting, or in
refraining from acting, hereunder in accordance with instructions signed by
Required Lenders, and such instructions of Required Lenders and any action
taken or failure to act pursuant thereto shall be binding on all of the
Lenders; provided, however, that the Administrative Agent shall not be required
to take any action which exposes the Administrative Agent to personal liability
or which is contrary to this Agreement or any other Loan Document or applicable
law.

         SECTION 9.02.  Rights of Co-Documentation Agents as a Lender.  With
respect to their respective Commitments, the Advances made by them and the
Notes issued to them, Paribas, Bank One and MeesPierson in their capacities as
Lenders hereunder shall have the same rights and powers hereunder as any other
Lender and may exercise the same as though they were not acting as the
Administrative Agent or Co-Documentation Agent, as applicable, and the term
"Lender" or "Lenders" shall, unless the context otherwise indicates, include
the Administrative Agent and Co-Documentation Agents in their individual
capacities.  The Administrative Agent and Co-Documentation Agents and their
Affiliates may (without having to account therefor to any Lender) accept
deposits from, lend money to, act as trustee under indentures of, provide
interest rate and commodities hedging services to, provide other merchant
banking services to, and generally engage in any kind of business with any
Company, any of their respective Subsidiaries, and any other Person who may do
business with or own securities of either Company or any of their respective
Subsidiaries, all as if they were not acting as the Administrative Agent or
Co-Documentation Agent and without any duty to account therefor to the Lenders.

         SECTION 9.03.  Sharing of Payments, Etc.  If any Lender shall obtain
any payment of any principal of or interest on any Advance made by it under
this Agreement or payment of any other Obligation, whether voluntary,
involuntary, through the exercise of any right of set-off, banker's lien,
counterclaim or similar right, or otherwise, in excess of its Pro Rata share
(determined based on the outstanding Advances), such Lender shall promptly
purchase from the other Lenders participation in the Obligations held by them
hereunder in such amounts, and make such other adjustments from time to time as
shall be necessary to cause such purchasing Lender to share the excess payment
ratably with each of the other Lenders in accordance with its Pro Rata portion
(determined based on the outstanding Advances) thereof.  To such end, all of
the Lenders shall make appropriate adjustments among themselves (by the resale
of participation sold or otherwise) if all or any portion





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 69
<PAGE>   76
of such excess payment is thereafter rescinded or must otherwise be restored.
Each Company agrees, to the fullest extent it may effectively do so under
applicable law, that any Lender so purchasing a participation in the
Obligations may exercise all rights of set-off, banker's lien, counterclaim, or
similar rights with respect to such participation as fully as if such Lender
were a direct holder of the Obligations in the amount of such participation.
Nothing contained herein shall require any Lender to exercise any such right or
shall affect the right of any Lender to exercise, and retain the benefits of
exercising, any such right with respect to any other indebtedness or obligation
of any Credit Party.

         SECTION 9.04.  Indemnification.  The Lenders hereby agree to indemnify
the Administrative Agent and the Co- Documentation Agents from and hold the
Administrative Agent and the Co-Documentation Agents harmless against (to the
extent not reimbursed under Sections 10.04 and 10.05, but without limiting the
obligations of the Companies under Section 10.04 or Section 10.05), ratably in
accordance with their respective Commitments, any and all liabilities,
obligations, losses, damages, penalties, actions, judgments, deficiencies,
suits, costs, expenses (including attorneys' fees), and disbursements of any
kind or nature whatsoever which may be imposed on, incurred or asserted against
the Administrative Agent or the Co-Documentation Agents in any way relating to
or arising out of the Original Credit Agreement, the First Amended Credit
Agreement, the Second Amended Credit Agreement, the Third Amended Credit
Agreement, any of the Related Transactions Documents, this Agreement or any
action taken or omitted to be taken by the Administrative Agent or the
Co-Documentation Agents under or in respect of the Original Credit Agreement,
the First Amended Credit Agreement, the Second Amended Credit Agreement, the
Third Amended Credit Agreement, or any of the Related Transactions Documents or
this Agreement; provided, however, that no Lender shall be liable for any
portion of the foregoing to the extent caused by the Administrative Agent's or
the Co-Documentation Agents' gross negligence or willful misconduct.  WITHOUT
LIMITATION OF THE FOREGOING, IT IS THE EXPRESS INTENTION OF THE LENDERS THAT
THE ADMINISTRATIVE AGENT AND THE CO-DOCUMENTATION AGENTS  SHALL BE INDEMNIFIED
HEREUNDER FROM AND HELD HARMLESS AGAINST ALL OF SUCH LIABILITIES, OBLIGATIONS,
LOSSES, DAMAGES, PENALTIES, ACTIONS, JUDGMENTS, DEFICIENCIES, SUITS, COSTS,
EXPENSES (INCLUDING ATTORNEYS' FEES) AND DISBURSEMENTS OF ANY KIND OR NATURE
DIRECTLY OR INDIRECTLY ARISING OUT OF OR RESULTING FROM THE SOLE OR
CONTRIBUTORY NEGLIGENCE OF THE ADMINISTRATIVE AGENT OR THE CO-DOCUMENTATION
AGENTS.  Without limiting any other provision of this Section, each Lender
agrees to reimburse the Administrative Agent and the Co-Documentation Agents
promptly upon demand for its Pro Rata share (calculated on the basis of the
Commitments) of any and all out- of-pocket expenses (including attorneys' fees)
incurred by the Administrative Agent or the Co-Documentation Agents in
connection with the preparation, execution, delivery, administration,
modification, amendment or enforcement (whether through negotiations, legal
proceedings, or otherwise) of, or legal advice in respect of rights or
responsibilities under, the Loan Documents, to the extent that the
Administrative Agent or the Co-Documentation Agents are not reimbursed for such
expenses by any Company.

         SECTION 9.05.  Independent Credit Decisions.  Each Lender agrees that
it has independently and without reliance on the Administrative Agent, the
Co-Documentation Agents or any other Lender, and based on such documentation
and information as it has deemed appropriate, made its





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 70
<PAGE>   77
own credit analysis of the Credit Parties and decision to enter into the
Original Credit Agreement, the First Amended Credit Agreement (to the extent
applicable), the Second Amended Credit Agreement, the Third Amended Credit
Agreement and this Agreement and that it will, independently and without
reliance upon the Administrative Agent, the Co-Documentation Agents  or any
other Lender, and based upon such documents and information as it shall deem
appropriate at the time, continue to make its own analysis and decisions in
taking or not taking action under this Agreement or any of the other Loan
Documents.  The Administrative Agent and the Co-Documentation Agents shall not
be required to keep themselves informed as to the performance or observance by
any Credit Party of this Agreement or any other Loan Document or to inspect the
properties or books of any Credit Party.  Except for notices, reports and other
documents and information expressly required to be furnished to the Lenders by
the Administrative Agent or the Co-Documentation Agents  hereunder or under the
other Loan Documents, the Administrative Agent and the Co-Documentation Agents
shall not have any duty or responsibility to provide any Lender with any credit
or other financial information concerning the affairs, financial condition or
business of any Credit Party (or any of their Affiliates) which may come into
the possession of the Administrative Agent, the Co-Documentation Agents or any
of their Affiliates.

         SECTION 9.06.  Several Commitments.  The Commitments and other
obligations of the Lenders under this Agreement are several.  The default by
any Lender in making an Advance in accordance with its Commitment shall not
relieve the other Lenders of their obligations under this Agreement.  In the
event of any default by any Lender in making any Advance, each nondefaulting
bank shall be obligated to make its Advance but shall not be obligated to
advance the amount which the defaulting Lender was required to advance
hereunder.  In no event shall any Lender be required to advance an amount or
amounts to any Borrower which shall in the aggregate exceed such Lender's
Commitment.  No Lender shall be responsible for any act or omission of any
other Lender.

         SECTION 9.07.  Successor Administrative Agent.  Subject to the
appointment and acceptance of a successor Administrative Agent as provided
below, the Administrative Agent may resign at any time by giving notice thereof
to the Lenders and Borrowers and the Administrative Agent may be removed at any
time if the Administrative Agent fails to perform its obligations hereunder by
the vote of all of the Lenders other than Paribas.  Upon any such resignation
or removal, the Lenders will have the right to appoint a successor
Administrative Agent with the consent of the Borrowers, unless any Default or
Event of Default shall have occurred and be continuing, in which case the
consent of the Borrowers shall not be required.  If no successor Administrative
Agent shall have been so appointed by the Lenders and shall have accepted such
appointment within thirty (30) days after the retiring Administrative Agent's
giving of notice of resignation or the Lenders' removal of the retiring
Administrative Agent, then the retiring Administrative Agent may, on behalf of
the Lenders, appoint a successor Administrative Agent, which shall be a
commercial bank organized under the laws of the United States of America or any
State thereof and having combined capital and surplus of at least One Hundred
Million Dollars ($100,000,000.00). Upon the acceptance of its appointment as
successor Administrative Agent, such successor Administrative Agent shall
thereupon succeed to and become vested with all rights, powers, privileges,
immunities, and duties of the resigning or removed Administrative Agent, and
the resigning or removed Administrative Agent shall be discharged from its
duties and obligations under this Agreement and the other Loan Documents.
After any Administrative Agent's resignation





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 71
<PAGE>   78
or removal as Administrative Agent, the provisions of this Article IX shall
continue in effect for its benefit in respect of any actions taken or omitted
to be taken by it while it was the Administrative Agent.

                                   ARTICLE X

                                 MISCELLANEOUS

         SECTION 10.01.  Notices, Etc.  All notices and other communications
provided for hereunder or under any other Loan Document shall be in writing and
shall be mailed, telegraphed, telecopied, telexed or delivered, to the intended
recipient at the "Address for Notices" specified below its name on the
signature pages hereto; or, as to each party, at such other address as shall be
designated by such party in a written notice to the other party complying as to
delivery with the terms of this Section 10.01. Except as otherwise provided in
this Agreement, all such communications shall be deemed to have been duly given
when transmitted by telex or telecopy, subject to telephone confirmation of
receipt, or when personally delivered or, in the case of a mailed notice, when
duly deposited in the mails, in each case given or addressed as aforesaid;
provided, however notices to the Administrative Agent pursuant to Sections 2.05
or 2.08 shall not be effective until received by the Administrative Agent.

         SECTION 10.02.  Amendments, Etc.  No amendment of any provision of
this Agreement, the Notes or any other Loan Document shall be effective unless
it is in writing and signed by the Credit Parties who are a party thereto and
the Required Lenders, and no waiver of any provision of this Agreement, the
Notes or any other Loan Document, nor consent to any departure by any Credit
Party therefrom (notwithstanding anything in any Loan Document to the
contrary), shall be effective unless it is in writing and signed by the
Required Lenders, and then such waiver or consent shall be effective only in
the specific instance and for the specific purpose for which given; provided,
that no amendment, waiver or consent shall, unless in writing and signed by all
of the Lenders and each applicable Credit Party, do any of the following: (a)
increase the Commitments of the Lenders or subject the Lenders to any
additional obligations; (b) reduce the principal of, or interest on, the Notes
or any fees or other amounts payable hereunder; (c) postpone any date fixed for
any payment of principal of, or interest on, the Notes or any fees or other
amounts payable hereunder; (d) waive any of the conditions specified in Article
V; (e) change the percentage of the Commitments or of the aggregate unpaid
principal amount of the Notes or the number of Lenders which shall be required
for the Lenders or any of them to take any action under this Agreement; (f)
change any provision contained in this Section 10.02; or (g) release any
Collateral (other than in accordance with Section 7.02(d)).  Notwithstanding
anything to the contrary contained in this Section, no amendment, waiver or
consent shall be made with respect to Article IX hereof without the prior
written consent of the Administrative Agent.

         SECTION 10.03.  No Waiver; Remedies, Etc.  No failure on the part of
the Administrative Agent or any Lender to exercise, and no delay in exercising
any right hereunder or under any other Loan Document shall operate as a waiver
thereof; nor shall any single or partial exercise of any right under any Loan
Document preclude any other or further exercise thereof or the exercise of any
other right.  The rights and remedies of the Administrative Agent and the
Lenders provided herein and in





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 72
<PAGE>   79
the other Loan Documents are cumulative and are in addition to, and not
exclusive of, any rights or remedies provided by law.  The rights of the
Administrative Agent and the Lenders under any Loan Document against any party
thereto are not conditional or contingent on any attempt by the Administrative
Agent or any Lender to exercise any of its rights under any other Loan Document
against such party or against any other Person.

         SECTION 10.04.  Fees, Costs, Expenses and Taxes.  Whether or not any
Advances are made hereunder or the transactions contemplated hereby are
consummated, each Company, jointly and severally, agrees to pay within ten (10)
days following demand (a) all fees, costs and expenses in connection with the
preparation, execution, delivery, filing, recording and administration of, and
any amendment, supplement or modification to, the Loan Documents, including,
without limitation, the reasonable fees and disbursements of counsel to the
Administrative Agent, and of any other special counsel or consultant retained
by the Administrative Agent with respect thereto and with respect to advising
the Administrative Agent as to its rights and responsibilities under the Loan
Documents, and (b) all costs and expenses, if any (including reasonable counsel
fees and disbursements), incurred in connection with the enforcement or
preservation of any rights under the Loan Documents and the other documents to
be delivered pursuant to the Loan Documents.  In addition, each Company will,
jointly and severally, pay any and all stamp and other taxes and fees payable
or determined to be payable in connection with the execution, delivery, filing
and recording of the Loan Documents, and will save the Administrative Agent and
each Lender harmless from and against any and all liabilities with respect to
or resulting from any delay in paying or omission to pay such taxes and fees.

         SECTION 10.05.  Indemnity.

                 (a)      Environmental Indemnity.  Each Company will, jointly
         and severally, defend, indemnify and hold harmless the Administrative
         Agent, the Co-Document Agents, each Lender, and their respective
         officers, directors, affiliates, employees and agents (each, an
         "Indemnified Party") from and against all losses, liabilities, claims,
         damages, penalties, judgments, costs and expenses (including
         reasonable attorneys' fees) of whatever kind or nature, known or
         unknown, contingent or otherwise, including, but without limitation,
         reasonable attorney and consultant fees, investigation and laboratory
         fees, court costs and litigation expenses incurred by any of them
         arising out of, or in any way relating to (i) any violation or any
         non-compliance or alleged non-compliance with any Environmental Laws
         by any Company or any of its Subsidiaries or by any other Person with
         whom any Company or any of its Subsidiaries are allegedly jointly,
         severally or contingently liable or responsible, or (ii) any Release
         or alleged Release into the environment of any Contaminant generated
         or allegedly generated by any Company or any of its Subsidiaries or by
         any other Person with whom any Company or any of its Subsidiaries are
         allegedly jointly, severally or contingently liable or responsible, or
         (iii) any material breach of any representation or warranty made by
         any Company in Section 6.1(s) hereof, Section 6.1(s) of the Original
         Credit Agreement, the First Amended Credit Agreement, the Second
         Amended Credit Agreement, the Third Amended Credit Agreement or this
         Agreement, (iv) the Administrative Agent's or any Lender's enforcement
         or attempted enforcement of any of the provisions of this Section
         10.05 or (v) otherwise arising in connection with any Environmental
         Claim relating to any Company, any of its Subsidiaries or their
         respective properties.





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 73
<PAGE>   80
                 (b)      General Indemnity.  In addition to the foregoing
         indemnity, each Company hereby jointly and severally indemnifies from,
         and holds each of the Indemnified Parties harmless against, any and
         all losses, liabilities, claims, damages, penalties, judgments, costs,
         and expenses (including reasonable attorneys' fees) to which any of
         them may become subject (other than those described in Section
         10.05(a)) which directly or indirectly arise from or relate to (i) the
         negotiation, execution, delivery, performance, administration,
         enforcement or existence of the Original Credit Agreement, the First
         Amended Credit Agreement, the Second Amended Credit Agreement, the
         Third Amended Credit Agreement, this Agreement, any Loan Documents or
         any of the Related Transactions Documents , (ii) any of the
         transactions contemplated by the Original Credit Agreement, the First
         Amended Credit Agreement, the Second Amended Credit Agreement, the
         Third Amended Credit Agreement, this Agreement,  or any of the Related
         Transactions Documents , (iii) any breach by any Credit Party of any
         representation, warranty, covenant, or other agreement contained in
         the Original Credit Agreement, the First Amended Credit Agreement, the
         Second Amended Credit Agreement, the Third Amended Credit Agreement,
         this Agreement, or any of the Related Transactions Documents, or (iv)
         any investigation, litigation, or other proceeding, including, without
         limitation, any threatened investigation, litigation, or other
         proceeding relating to any of the foregoing.

                 (c)      Provisions Applicable to All Indemnities.  WITHOUT
         LIMITING ANY PROVISION OF THIS AGREEMENT OR OF ANY OTHER LOAN
         DOCUMENT, IT IS THE EXPRESS INTENTION OF THE PARTIES HERETO THAT EACH
         INDEMNIFIED PARTY SHALL BE INDEMNIFIED FROM AND HELD HARMLESS AGAINST
         ANY AND ALL LOSSES, LIABILITIES, CLAIMS, DAMAGES, PENALTIES,
         JUDGMENTS, COSTS, AND EXPENSES (INCLUDING REASONABLE ATTORNEYS' FEES)
         ARISING OUT OF OR RESULTING FROM THE SOLE OR CONTRIBUTORY NEGLIGENCE
         OF THE INDEMNIFIED PARTY; provided, however, that the indemnities
         provided for in this Section 10.05 shall not apply to any loss,
         damage, liability, claim, damage, penalties, judgments, cost or
         expense (or the applicable part thereof) resulting from, or
         attributable to, any bad faith, gross negligence or willful misconduct
         of any Indemnified Party.  The provisions of this Section 10.05 shall
         survive the repayment of the Obligations, and shall continue
         thereafter in full force and effect, notwithstanding the foreclosure
         of any Security Document or realization on any other Collateral, and
         notwithstanding any insolvency, bankruptcy or reorganization of any
         Credit Party.

         SECTION 10.06.  Right of Set-off.  Upon the occurrence and during the
continuance of any Event of Default, the Administrative Agent and any Lender
may, and is hereby authorized to, at any time and from time to time, without
notice to any Company (any such notice being expressly waived by each Company)
and to the fullest extent permitted by law, set off and apply any and all
deposits (general or special, time or demand, provisional or final) at any time
held and other indebtedness at any time owing by Administrative Agent or any
Lender to or for the credit or the account of any Borrower or Holdings against
any and all Obligations now or hereafter existing under any Loan Document,
irrespective of whether or not the Administrative Agent or any Lender shall
have made any demand hereunder or thereunder and although such Obligations may
be contingent or unmatured.





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 74
<PAGE>   81
The Administrative Agent or any Lender exercising the right of set-off agrees
promptly to notify the Borrowers, after any such set-off and application,
provided, however, that the failure to give such notice shall not affect the
validity of such set-off and application or otherwise subject the
Administrative Agent or the Lenders to liability of any kind or nature
whatsoever.  The rights of the Administrative Agent and any Lender under this
Section 10.06 are in addition to the other rights and remedies (including,
without limitation, other rights of set-off) which the Administrative Agent and
any Lender may have.

         SECTION 10.07.  Severability.  Any provision of this Agreement, or of
any other Loan Document to which any Company is a party, which is prohibited or
unenforceable in any jurisdiction shall, as to such jurisdiction, be
ineffective to the extent of such prohibition or unenforceability without
invalidating the remaining portions hereof or thereof or affecting the validity
or enforceability of such provision in any other jurisdiction.

         SECTION 10.08.  Successors and Assigns.

         (a)     Binding Effect.  This Agreement shall be binding upon and
inure to the benefit of the Borrowers, Holdings, the Administrative Agent and
the Lenders and their respective successors and assigns, except that neither
the Borrowers nor Holdings may assign their rights hereunder or any interest
herein without the prior written consent of all the Lenders.

         (b)     Participations.  Any Lender may sell participations to one or
more banks or other institutions in all or a portion of its rights and
obligations under this Agreement and the other Loan Documents (including,
without limitation, all or a portion of its Commitments and the Advances owing
to it); provided, however, that (i) such Lender's obligations under this
Agreement and the other Loan Documents (including, without limitation, its
Commitment) shall remain unchanged, (ii) such Lender shall remain solely
responsible to the Borrowers for the performance of such obligations, (iii)
such Lender shall remain the holder of its Note for all purposes of this
Agreement, (iv) the Borrowers shall continue to deal solely and directly with
such Lender in connection with such Lender's rights and obligations under this
Agreement and the other Loan Documents, and (v) such Lender shall not sell a
participation that conveys to the participant the right to vote or give or
withhold consents under this Agreement or any other Loan Document, other than
the right to vote upon or consent to (1) any increase of such Lender's
Commitment, (2) any reduction of the principal amount of, or interest to be
paid on, the Advances or the Note of such Lender, (3) any reduction of any
commitment fee or other amount payable to such Lender under any Loan Document,
or (4) any postponement of any date for the payment of any amount payable in
respect of the Advances or Note of such Lender.  Any Lender who has sold a
participation under this Section 10.08, may on behalf of the participant but
subject to the next sentence of this clause (b), make claims hereunder in its
own name for amounts incurred by the participant which would be payable by the
Borrowers under Section 3.06 or Article IV hereof if such participant were a
Lender and in furtherance of the foregoing, the Borrowers agree that the
provisions of Section 3.06 and Article IV run to the benefit of each such
participant.  Except in respect of the Reserve Requirements, no participant in
the Advances and the Note of a Lender shall be entitled to receive any greater
payment from the Borrowers than the Lender or, if greater, any bank which is a
member of the Federal Reserve System (and subject only to the laws, regulations
and administrative practices in effect in the United States)





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 75
<PAGE>   82
would have been entitled to receive had the Lender or such bank held the
interest in the Advances and the Note held by such participant.  No Lender nor
any participant in the Advances and the Note of a Lender that has changed its
Applicable Lending Office shall be entitled to receive any greater payment from
the Borrowers than it would have received had it not changed its Applicable
Lending Office unless the Lender or such participant was required to change its
Applicable Lending office as provided in Sections 4.01(c) and 4.03 hereof.

         (c)     Assignments by Lenders.  No Lender may assign any portion of
its rights or obligations under this Agreement and the other Loan Documents
without the consent of the Administrative Agent and, prior to the occurrence of
an Event of Default, the Borrowers, which consents shall not be unreasonably
withheld by either the Administrative Agent or the Borrowers.  With respect to
any permitted assignment by a Lender of its rights and obligations hereunder or
any portion thereof, the Administrative Agent shall maintain at its address
referred to on the signature pages hereto a copy of each assignment by a Lender
delivered to and accepted by it in a register (which may be a computer record)
for the recordation of the names and addresses of the assignees under this
Section 10.08 and the Commitments of, and the principal amount of the Advances
owing to, each such assignee from time to time (the "Register").  The entries
in the Register shall be conclusive and binding for all purposes, absent
manifest error, and each Company, the Lenders, and the assignees may treat each
Person whose name is recorded in the Register as a Lender hereunder for all
purposes of this Agreement.  The Register shall be available for inspection by
each Company, any Lender, or any assignee at any reasonable time and from time
to time upon reasonable prior notice.

         (d)     Deliveries of Information.  Any Lender may furnish any
information concerning any Company or any of its Subsidiaries in the possession
of such Lender from time to time to assignees and participants (including
prospective assignees and participants), subject, however, to the requirements
of Section 10.16.

         SECTION 10.09.  Counterparts.  This Agreement may be executed in any
number of counterparts and by different parties hereto in separate
counterparts, each of which shall be deemed to be an original at such time as
both parties have executed a counterpart, but all of which taken together shall
constitute one and the same agreement.

         SECTION 10.10.  Headings.  Section headings herein are included for
convenience of reference only and shall not constitute a part of this Agreement
for any other purpose.

         SECTION 10.11.  Governing Law.  This Agreement and the Notes shall be
governed by, and construed in accordance with, the law of the State of New
York, without regard to principles of conflicts of law and the applicable laws
of the United States of America.  The parties submit to the non-exclusive
jurisdiction of the courts of the State of New York and the United States
District Courts located in New York, New York with respect to any action or
proceeding relating to the Loan Documents.

         SECTION 10.12.  WAIVER OF JURY TRIAL.  EACH COMPANY WAIVES ANY RIGHT
TO A TRIAL BY JURY IN ANY ACTION, PROCEEDING OR COUNTERCLAIM CONCERNING ANY
RIGHTS UNDER THIS AGREEMENT, ANY NOTE OR OTHER





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 76
<PAGE>   83
LOAN DOCUMENT OR UNDER ANY AMENDMENT, WAIVER, CONSENT, INSTRUMENT, DOCUMENT OR
OTHER AGREEMENT DELIVERED OR WHICH IN THE FUTURE MAY BE DELIVERED IN CONNECTION
THEREWITH, OR ARISING IN CONNECTION WITH ANY RELATIONSHIP EXISTING IN
CONNECTION WITH THIS AGREEMENT, AND AGREES THAT ANY SUCH ACTION, PROCEEDING OR
COUNTERCLAIM SHALL BE TRIED BEFORE A COURT AND NOT BEFORE A JURY.

         SECTION 10.13.  Maximum Interest Rate.  No provision of this Agreement
or of any other Loan Document shall require the payment or the collection of
interest in excess of the maximum permitted by applicable law.  If any excess
of interest in such respect is hereby provided for, or shall be adjudicated to
be so provided, in any Loan Document or otherwise in connection with this loan
transaction, the provisions of this Section 10.13 shall govern and prevail and
neither of the Companies nor the sureties, guarantors, successors, or assigns
of any of the Companies shall be obligated to pay the excess amount of such
interest or any other excess sum paid for the use, forbearance, or detention of
sums loaned pursuant hereto.  In the event any Lender ever receives, collects,
or applies as interest any such sum, such amount which would be in excess of
the maximum amount permitted by applicable law shall be applied as a payment
and reduction of the principal of the indebtedness evidenced by the Notes; and,
if the principal of the Notes has been paid in full, any remaining excess shall
forthwith be paid to the Borrowers.  In determining whether or not the interest
paid or payable exceeds the Maximum Rate, the Borrowers and each Lender shall,
to the extent permitted by applicable law, (i) characterize any nonprincipal
payment as an expense, fee, or premium rather than as interest, (ii) exclude
voluntary prepayments and the effects thereof, and (iii) amortize, prorate,
allocate, and spread in equal or unequal parts the total amount of interest
throughout the entire contemplated term of the indebtedness evidenced by the
Notes so that interest for the entire term does not exceed the Maximum Rate.
Without limiting the generality of the foregoing, if and to the extent
necessary to ensure compliance with this Section 10.13, what would otherwise be
the joint and several liability of a Borrower with respect to any Advances and
any Notes shall instead be deemed to be the liability of such Borrower as a
guarantor of payment of such Advances and not as a co-borrower of such Advances
or as a co-maker of such Notes.  In furtherance of the foregoing, each Borrower
hereby irrevocable and unconditionally guarantees to the Administrative Agent
and the Lenders the punctual payment and performance of the obligations of each
other Borrower under the Loan Documents, including without limitations the
timely payment of the Obligations.

         SECTION 10.14.  Non-Application of Chapter 15 of Texas Credit Code.
The provisions of Chapter 15 of the Texas Credit Code (Vernon's Texas Civil
Statutes, Article 5069-15) are specifically declared by the parties hereto not
to be applicable to this Agreement or any of the other Loan Documents or to the
transactions contemplated hereby.

         SECTION 10.15.  Construction.  Each Company, the Administrative Agent,
and each Lender acknowledges that each of them has had the benefit of legal
counsel of its own choice and has been afforded an opportunity to review this
Agreement and the other Loan Documents with its legal counsel and that this
Agreement and the other Loan Documents shall be construed as if jointly drafted
by the parties hereto.





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 77
<PAGE>   84
         SECTION 10.16.  Confidentiality.  The Administrative Agent and each
Lender agrees (on behalf of itself and each of its affiliates, directors,
officers, employees and representatives) to use reasonable precautions to keep
confidential, in accordance with its customary procedures for handling
confidential information of this nature and in accordance with safe and sound
banking practices, any non-public information supplied to it by any Company or
any Subsidiary of any Company pursuant to this Agreement which is identified by
either such Company or such Subsidiary as being confidential at the time the
same is delivered to the Administrative Agent or any Lender, provided that
nothing herein shall limit the disclosure of any such information (a) to the
extent required by statute, rule, regulation or judicial process, (b) to
counsel for the Administrative Agent or any Lender, (c) in connection with the
enforcement of the Loan Documents and in any litigation to which the
Administrative Agent or any Lender is a party or (d) to any permitted assignee
or participant (or prospective permitted assignee or participant) so long as
such permitted assignee or participant (or prospective permitted assignee or
participant) first enters into a confidentiality agreement with the
Administrative Agent or such Lender binding itself to comply with the terms of
this Section 10.16.

         SECTION 10.17.  Survival.  All representations and warranties made in
this Agreement or any other Loan Document or in any document, statement, or
certificate furnished in connection with this Agreement shall survive the
execution and delivery of this Agreement and the other Loan Documents, and no
investigation by the Administrative Agent or any Lender or any closing shall
affect the representations and warranties or the right of the Administrative
Agent or any Lender to rely upon them.  Without prejudice to the survival of
any other obligation of the Borrowers and Holdings hereunder, the obligations
of the Borrowers and Holdings under Article IV and Sections 10.04 and 10.05
shall survive repayment of the Obligations and termination of the Commitments.

         SECTION 10.18.  Joint and Several Obligations.  Each and every
representation, warranty, covenant or agreement of the Companies contained
herein shall be, and shall be deemed to be, the joint and several
representation, warranty, covenant and agreement of each of the Companies and
of all such Persons.  In addition, the indebtedness, liabilities and
obligations of the Borrowers shall be, and shall be deemed to be, the joint and
several indebtedness, liabilities and obligations of each of the Borrowers and
of all Borrowers.  Notwithstanding the foregoing, if and to the extent that the
joint and several liability of a Borrower with respect to any Advance or
Advances made to another Borrower is determined by a court of competent
jurisdiction to cause the obligations of such Borrower to repay such Advance or
Advances to be subject to avoidance under Sections 544, 548 or 550 of the
Bankruptcy Code or subject to being set aside or annulled under any applicable
state law relating to fraud on creditors, the amount of such joint and several
or co-maker liability of such Borrower shall, without any further action by any
Borrower, the Administrative Agent or any Lender, be automatically limited to
the greatest amount which is valid and enforceable as determined in such
proceeding; provided, however, that for purposes of this sentence it shall be
presumed that the joint and several liabilities of the Borrowers under this
Agreement and the Notes do not equal or exceed an aggregate amount which would
render any such Borrower's obligations under this Agreement or any Note subject
to being avoided, set aside or annulled, and the burden of proof to the
contrary shall be on the party asserting to the contrary.

         SECTION 10.19.  ENTIRE AGREEMENT; AMENDMENT AND RESTATEMENT.





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 78
<PAGE>   85
         (a)     This Agreement amends and restates in its entirety the Third
Amended Credit Agreement which amended and restated the terms and provisions of
the Second Amended Credit Agreement, which amended and restated the terms and
provisions of the First Amended Credit Agreement, which amended and restated
the terms and provisions of the Original Credit Agreement in its entirety,
which amended and restated the terms and provisions of the Canada Trust Credit
Agreement in its entirety.  The execution of this Agreement, the Notes and the
other Loan Documents executed in connection herewith does not constitute a
novation with respect to indebtedness outstanding in connection with the
Original Credit Agreement, the First Amended Credit Agreement, the Second
Amended Credit Agreement, the Third Amended Credit Agreement, the Canada Trust
Credit Agreement, or the indebtedness evidenced by the Canada Trust Note or any
Note executed prior to the Closing Date.  The parties hereto hereby ratify and
confirm each of the Loan Documents entered into prior to the Closing Date,
including without limitation, the Guaranty and the other Security Documents and
agree that such Loan Documents continue to be legal, valid, binding and
enforceable in accordance with their respective terms.  Without limiting the
generality of the foregoing, the parties hereto agree and acknowledge that (i)
the Liens created by the (A) the Original Security Agreement, Additional
Security Agreement, the Oklahoma Mortgage and the Holdings Pledge Agreement
secure the Obligations as defined hereby, including without limitation, the
obligations, indebtedness and liability of the Credit Parties arising in
connection with this Agreement and the Loan Documents executed by the Credit
Parties pursuant hereto and (B) the Deed of Trust and Mortgage secure the
Obligations of the Borrowers; (ii) the term "Credit Agreement" as used in the
Security Documents, includes without limitation, this Agreement; and (iii) the
term "Security Documents" as defined in the Security Documents includes,
without limitation, the New Mortgage Documents, the Subsidiary Guaranties, the
Holdings Pledge Agreement, the Borrower Pledge Agreement and the Mid Louisiana
Pledge Agreement.

         (b)     THIS AGREEMENT, THE NOTES, AND THE OTHER LOAN DOCUMENTS
REFERRED TO HEREIN EMBODY THE FINAL, ENTIRE AGREEMENT AMONG THE PARTIES HERETO
AND SUPERSEDE ANY AND ALL PRIOR COMMITMENTS, AGREEMENTS, REPRESENTATIONS, AND
UNDERSTANDINGS, WHETHER WRITTEN OR ORAL, RELATING TO THE SUBJECT MATTER HEREOF
(INCLUDING, WITHOUT LIMITATION, THE FIRST AMENDED CREDIT AGREEMENT, THE SECOND
AMENDED CREDIT AGREEMENT, THE THIRD AMENDED CREDIT AGREEMENT, THE ORIGINAL
CREDIT AGREEMENT AND THE CANADA TRUST CREDIT AGREEMENT) AND MAY NOT BE
CONTRADICTED OR VARIED BY EVIDENCE OF PRIOR, CONTEMPORANEOUS, OR SUBSEQUENT
ORAL AGREEMENTS OR DISCUSSIONS OF THE PARTIES HERETO.  THERE ARE NO ORAL
AGREEMENTS AMONG THE PARTIES HERETO.





           [The remainder of this page is intentionally left blank.]





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 79
<PAGE>   86

         IN WITNESS WHEREOF, the Borrowers, Holdings, the Administrative Agent,
the Co-Documentation Agents and the Lenders have executed this Agreement as of
the date first written above.

                             BORROWERS:
                             ---------

                             COHO RESOURCES, INC.


                             By:
                                ----------------------------------------------
                                      Eddie M. LeBlanc, III
                                      Senior Vice President and
                                      Chief Financial Officer



                             Address for Notices:
                             -------------------
                             14785 Preston Road, Suite 860
                             Dallas, Texas 75240
                             Telephone No.:   214-991-9493
                             Telecopy No.:    214-991-8514
                             Attention:         Eddie M. LeBlanc, III
                                                President





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 80
<PAGE>   87
                             COHO LOUISIANA PRODUCTION COMPANY


                             By:
                                ----------------------------------------------
                                      Eddie M. LeBlanc, III
                                      Senior Vice President and
                                      Chief Financial Officer

                             Address for Notices:
                             -------------------
                             14785 Preston Road, Suite 860
                             Dallas, Texas 75240
                             Telephone No.:   214-991-9493
                             Telecopy No.:    214-991-8514
                             Attention:         Eddie M. LeBlanc, III
                                                Senior Vice President and
                                                Chief Financial Officer


                             COHO EXPLORATION, INC.


                             By:
                                ----------------------------------------------
                                      Eddie M. LeBlanc, III
                                      Senior Vice President and
                                      Chief Financial Officer

                             Address for Notices:
                             -------------------
                             14785 Preston Road, Suite 860
                             Dallas, Texas 75240
                             Telephone No.:   214-991-9493
                             Telecopy No.:    214-991-8514
                             Attention:         Eddie M. LeBlanc, III
                                                Senior Vice President





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 81
<PAGE>   88
                             COHO ACQUISITIONS COMPANY


                             By:
                                ----------------------------------------------
                                      Eddie M. LeBlanc, III
                                      Senior Vice President and
                                      Chief Financial Officer

                             Address for Notices:
                             -------------------
                             14785 Preston Road, Suite 860
                             Dallas, Texas 75240
                             Telephone No.:   214-991-9493
                             Telecopy No.:    214-991-8514
                             Attention:         Eddie M. LeBlanc, III
                                                Senior Vice President

                             HOLDINGS:
                             --------

                             COHO ENERGY, INC.


                             By:
                                ----------------------------------------------
                                      Eddie M. LeBlanc, III
                                      Senior Vice President and
                                      Chief Financial Officer

                             Address for Notices:
                             -------------------
                             14785 Preston Road, Suite 860
                             Dallas, Texas 75240
                             Telephone No.:   214-991-9493
                             Telecopy No.:    214-991-8514
                             Attention:         Eddie M. LeBlanc, III
                                                Senior Vice President





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 82
<PAGE>   89
                             ADMINISTRATIVE AGENT,
                             ----------------------
                             CO-DOCUMENTATION AGENTS AND LENDERS:
                             ------------------------------------

Commitment:                  BANQUE PARIBAS, Houston Agency
----------
$40,000,000.00               as Administrative Agent for Lenders and
                             as a Lender


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


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

                             Address for Notices:
                             -------------------
                             1200 Smith Street, Suite 3100
                             Houston, Texas 77002
                             Telephone No.:   713-659-4811
                             Telecopy No.:    713-659-6915

                             With a copy to:
                             --------------
                             2121 San Jacinto, Suite 930
                             Dallas, Texas 75201
                             Telephone No.:   214-969-0380
                             Telecopy No.:    214-969-0260

                             Lending Office for Prime Rate Advances
                             --------------------------------------
                             1200 Smith Street, Suite 3100
                             Houston, Texas 77002

                             Lending Office for Eurodollar Advances
                             --------------------------------------
                             1200 Smith Street, Suite 3100
                             Houston, Texas 77002





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 83
<PAGE>   90
Commitment:                  MEESPIERSON CAPITAL CORP., as
----------
$40,000,000.00               Co-Documentation Agent for the
                             Lenders and as a Lender


                             By:
                                ----------------------------------------------


                             By:
                                ----------------------------------------------

                             Address for Operational Notices:
                             -------------------------------
                             MeesPierson Capital Corp.
                             300 Crescent Court, Suite 1750
                             Dallas, Texas 75201
                             Telephone No.:   214-754-0009
                             Telecopy No.:      214-754-5981
                             Attention:         Yolanda Ditmar

                             Address for Other Notices:
                             -------------------------
                             MeesPierson N.V.
                             300 Crescent Court, Suite 1750
                             Dallas, Texas 75201
                             Telephone No.:   214-754-0009
                             Telecopy No.:      214-754-5981
                             Attention:         Karel Louman
                                                Vice President & Manager

                             Lending Office for Prime Rate Advances
                             --------------------------------------
                             445 Park Avenue
                             New York, New York 10022

                             Lending Office for Eurodollar Advances
                             --------------------------------------
                             445 Park Avenue
                             New York, New York 10022





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 84
<PAGE>   91
Commitment:                  BANK ONE, TEXAS, N.A., as
----------
$40,000,000.00               Co-Documentation Agent for the
                             Lenders and as a Lender


                             By:
                                ----------------------------------------------
                                      John A. Clark
                                      Assistant Vice President

                             Address for Notices:
                             -------------------
                             1717 Main Street, 4th Floor
                             Dallas, Texas 75201
                             Telephone No.:   214-290-3097
                             Telecopy No.:      214-290-2332
                             Attention:         John A. Clark
                                                Assistant Vice President

                             Lending Office for Prime Rate Advance:
                             -------------------------------------
                             1717 Main Street
                             Dallas, Texas 75201

                             Lending Office for Eurodollar Advances:
                             --------------------------------------
                             1717 Main Street
                             Dallas, Texas 75201





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 85
<PAGE>   92
Commitment:                  BANK OF SCOTLAND
----------
$37,500,000.00

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


                             Address for Notices for operational matters:
                             -------------------------------------------
                             Bank of Scotland, Grand Cayman
                             c/o 565 5th Avenue
                             New York, New York 10017
                             Telephone No.:   212-450-0872
                             Telecopy No.:    212-557-9460
                             Attention:         Janet Taffe
                                                Assistant Vice President

                             Addresses for Notices for credit matters:
                             ----------------------------------------
                             Bank of Scotland
                             Two Allen Center
                             1200 Smith Street, Suite 1750
                             Houston, Texas 77002
                             Telephone No.:   713-651-1870
                             Telecopy No.:    713-651-9714
                             Attention:         Rex McSwain
                                                Vice President

                             Lending Office for Prime Rate Advances
                             --------------------------------------
                             565 5th Avenue
                             New York, New York 10017

                             Lending Office for Eurodollar Advances
                             --------------------------------------
                             565 5th Avenue
                             New York, New York 10017





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 86
<PAGE>   93
Commitment:                  CREDIT LYONNAIS NEW YORK BRANCH
----------
$37,500,000.00

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

                             Address for Notices for operational matters:
                             -------------------------------------------
                             c/o Credit Lyonnais Houston Representative Office
                             1000 Louisiana, Suite 5360
                             Houston, Texas 77002
                             Telephone No.:   713-751-0500
                             Telecopy No.:    713-751-0307
                             Attention:         Bernadette Archie

                             Addresses for Notices for credit matters:
                             ----------------------------------------
                             c/o Credit Lyonnais Houston Representative Office
                             1000 Louisiana, Suite 5360
                             Houston, Texas 77002
                             Telephone No.:   713-751-0500
                             Telecopy No.:    713-751-0307
                             Attention:         Mr. Timothy DeSpain

                             Lending Office for Prime Rate Advances
                             --------------------------------------
                             1301 Avenue of the Americas
                             New York, New York 10019

                             Lending Office for Eurodollar Advances
                             --------------------------------------
                             1301 Avenue of the Americas
                             New York, New York 10019





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 87
<PAGE>   94
Commitment:                  CHRISTIANIA BANK OG KREDITKASSE, ASA
----------
$27,500,000.00


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


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

                             Address for Notices:
                             -------------------
                             Christiania Bank OG Kreditkasse
                             11 West 42nd Street, 7th Floor
                             New York, New York 10036
                             Telephone No.:   212-827-4800
                             Telecopy No.:    212-827-4888
                             Attention:         Mr. William S. Phillips

                             Lending Office for Prime Rate Advances
                             --------------------------------------
                             11 West 42nd Street, 7th Floor
                             New York, New York 10036

                             Lending Office for Eurodollar Advances
                             --------------------------------------
                             11 West 42nd Street, 7th Floor
                             New York, New York 10036





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 88
<PAGE>   95
Commitment:                  DEN NORSKE BANK ASA
----------
$37,500,000.00

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


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


                             Address for Notices:
                             -------------------
                             Den norske Bank ASA
                             200 Park Avenue, 31st Floor
                             New York, New York 10166
                             Telephone No.:   212-681-3800
                             Telecopy No.:    212-681-3900
                             Attention:         Customer Service

                             With a copy to:
                             --------------
                             Den norske Bank ASA
                             Three Allen Center
                             333 Clay Street, Suite 4890
                             Houston, Texas 77002
                             Telephone No.:   713-844-9254
                             Telecopy No.:    713-757-1167
                             Attention:         Mr. J. Morten Kreutz
                                                Vice President

                             Lending Office for Prime Rate Advances
                             --------------------------------------
                             200 Park Avenue, 31st Floor
                             New York, New York 10166

                             Lending Office for Eurodollar Advances
                             --------------------------------------
                             200 Park Avenue, 31st Floor
                             New York, New York 10166





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 89
<PAGE>   96
Commitment:                  TORONTO DOMINION (TEXAS), INC.
----------
$17,500,000.00

                             By:
                                ----------------------------------------------
                                      Neva Nesbitt
                                      Vice President

                             Address for Notices:
                             -------------------
                             909 Fannin, Suite 1700
                             Houston, Texas 77010
                             Telephone No.:   713-653-8261
                             Telecopy No.:    713-951-9921
                             Attention:         Neva Nesbitt
                                                Vice President

                             Lending Office for Prime Rate Advances
                             --------------------------------------
                             909 Fannin, Suite 1700
                             Houston, Texas 77010

                             Lending Office for Eurodollar Advances
                             --------------------------------------
                             909 Fannin, Suite 1700
                             Houston, Texas 77010





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 90
<PAGE>   97
Commitment:                  BANK OF MONTREAL
----------
$22,500,000.00

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

                             Address for Notices and Other Reports:
                             -------------------------------------
                             700 Louisiana, Suite 4400
                             Houston, Texas 77002
                             Telephone No.:   713-546-9724
                             Telecopy No.:      713-223-4007
                             Attention:         Anne-Marie Goodwin

                             Lending Office for Prime Rate Advances
                             --------------------------------------
                             115 South LaSalle Street, 11W
                             Chicago, Illinois 60603

                             Lending Office for Eurodollar Advances
                             --------------------------------------
                             115 South LaSalle Street, 11W
                             Chicago, Illinois 60603





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 91
<PAGE>   98
                           COHO CANADA ACKNOWLEDGMENT


         Coho Resources Limited hereby consents and agrees to the execution and
delivery of this Agreement, ratifies and confirms that the certain Negative
Pledge Agreement dated February 8, 1994, executed by Coho Resources Limited for
the benefit of the Administrative Agent and the Lenders is in full force and
effect; agrees that it continues to be legal, valid, binding and enforceable in
accordance with its terms and acknowledges and agrees that the term "Credit
Agreement" as defined therein means this Agreement.

                             COHO RESOURCES LIMITED


                             By:
                                ----------------------------------------------
                                     Eddie M. LeBlanc, III
                                     Treasurer





FOURTH AMENDED AND RESTATED CREDIT AGREEMENT, PAGE 92
<PAGE>   99
                                SCHEDULE 6.01(e)
                                       to
                          FOURTH AMENDED AND RESTATED
                                CREDIT AGREEMENT


                                  SUBSIDIARIES


<TABLE>
<CAPTION>
=====================================================================================================================
                              Jurisdiction             Authorized
        Subsidiary          Of Incorporation         Capitalization             Outstanding         % Owned
=====================================================================================================================
 <S>                      <C>                 <C>                              <C>                 <C>
                                                 A.  Holdings
---------------------------------------------------------------------------------------------------------------------
 1.   Coho Canada         Alberta, Canada     1.    Unlimited Common           1.   31,432,517     100%

                                              2.    2,000,000 first            2.   None
                                                    preferred shares

                                              3.    5,000,000 second           3.   None
                                                    preferred shares

                                              4.    Unlimited nonvoting        4.   None
                                                    common
---------------------------------------------------------------------------------------------------------------------
 2.   Coho Shell          Delaware            1000 shares common               1000                100%
---------------------------------------------------------------------------------------------------------------------
 3.   CRI                 Nevada              1.    50,000,000 common          1.   7,505,275      100% of common
                                                    stock, $.01 par value                          0% of Class A

                                              2.    8,000,000 class A          2.   8,000,000      common
                                                    Common Stock, $.01 par
                                                    value

                                              3.    10,000,000 shares of       3.   None
                                                    preferred stock $.01
                                                    par value
---------------------------------------------------------------------------------------------------------------------
                                                B.  Coho Canada
---------------------------------------------------------------------------------------------------------------------
 1.   CRI                 Nevada              1.    50,000,000 common          1.   7,505,275      0% of common
                                                    stock, $.01 par value

                                              2.    8,000,000 class A          2.   8,000,000      100% of Class A
                                                    Common Stock, $.01 par                         Common
                                                    value

                                              3.    10,000,000 shares of       3.   None.
                                                    preferred stock $.01
                                                    par value
---------------------------------------------------------------------------------------------------------------------
 2.   Profile Petroleum   Alberta             Unlimited common shares, no      888,002             100%
      Ltd.                                    par value
---------------------------------------------------------------------------------------------------------------------
 3.   Grayon Developments Alberta             1.    Unlimited common           1.   5,290,020      100%
      Ltd.                                          shares, no par value

                                              2.    Unlimited First            2.   320,250        100%
                                                    Preferred, no par
                                                    value
                                                                               3.   2,000          100%
                                              3.    Unlimited Second
                                                    Preferred, no par
                                                    value
---------------------------------------------------------------------------------------------------------------------
 4.   Coho International  Bahamas             5,000 common shares, $1 par      3,000               100%
      Ltd.                                    value
======================================================================================================================
</TABLE>





SCHEDULE 6.01(e), PAGE 1 OF 2
<PAGE>   100
<TABLE>
<CAPTION>
======================================================================================================================
                              Jurisdiction             Authorized
        Subsidiary          Of Incorporation         Capitalization            Outstanding         % Owned
======================================================================================================================
 <S>                      <C>                 <C>                              <C>                 <C>
----------------------------------------------------------------------------------------------------------------------
                                                    C.  CRI
----------------------------------------------------------------------------------------------------------------------
 1.   Tierra Exploration, Nevada              2,500 common stock, $0.01        100                 100%
      Inc.                                    par value
----------------------------------------------------------------------------------------------------------------------
 2.   Coho Marketing and  Nevada              1.    1,000 common stock, no     1.   100            100%
      Transportation,                               par value
      Inc.
                                              2.    1,000 shares of            2.   None
                                                    preferred stock, no
                                                    par value
----------------------------------------------------------------------------------------------------------------------
 3.   ING                 Delaware            1.    600,000 common stock,      1.   20,000         100% of Common
                                                    $.01 par value
                                                                                                   100% of
                                              2.    250,000 preferred          2.   200,025 series Preferred
                                                    stock, $.01 par value           8% Preferred
----------------------------------------------------------------------------------------------------------------------
 4.   Coho Anaguid Inc.   Delaware            1.    9,870  common stock,       1.   2,700          100%
                                                    $0.01 par value

                                              2.    130  preferred stock,      2.   120            100% by Coho
                                                    $20,000 par value                              Interna-
                                                                                                   tional
----------------------------------------------------------------------------------------------------------------------
                                                    D. ING
----------------------------------------------------------------------------------------------------------------------
 1.   Production Company  Delaware            1,000 shares of common           1,000               100%
                                              stock, $.10 par value
----------------------------------------------------------------------------------------------------------------------
 2.   Coho Fairbanks      Delaware            1,000 shares of common           1,000               100%
      Gathering Company                       stock, $.10 par value
----------------------------------------------------------------------------------------------------------------------
 3.   Coho Louisiana      Delaware            1,000 shares of common           1,000               100%
      Gathering Company                       stock, $.10 par value
----------------------------------------------------------------------------------------------------------------------
 4.   Coho Exploration,   Delaware            1,000 shares of common           1,000               100%
      Inc.                                    stock, $.10 par value
======================================================================================================================
</TABLE>





SCHEDULE 6.01(e), PAGE 2 OF 2
<PAGE>   101
                                SCHEDULE 6.01(f)
                                       to
                          FOURTH AMENDED AND RESTATED
                                CREDIT AGREEMENT


                                   LITIGATION

A.       Coho Resources, Inc.

         1.      Wall & Redekop Petroleum Inc. vs. Coho Resources, Inc. (1983)

                 Alleging amounts owing by CRI

                 Claim amount approximately $150,000

         2.      Humble Resources Management, Inc. vs. Coho Resources, Inc.
                 (1991)

                 Alleging economic loss by drainage of oil

                 Claiming actual, incidental, compensatory and punitive damages

                 Lawsuit will expire through statute of limitations.
                 Properties no longer owned by CRI.

         3.      During June and July, 1994, CRI, together with several
                 companies, was named as a defendant in three lawsuits filed in
                 Mississippi.  The lawsuits, which are basically identical,
                 involve claims by landowners for purported damages caused by
                 naturally occurring radioactive materials at various wellsite
                 locations on land leased by CRI in Mississippi.  The
                 plaintiffs are seeking compensatory and punitive damages,
                 including damages for "emotional distress".  Two of these
                 lawsuits have been settled.  The well sites contained in the
                 third lawsuit have been remediated, and the lawsuit has no
                 activity currently pending.

         4.      Douglas Osbourne and Sandra Osbourne vs. Coho Resources, Inc.
                 CRI purchased an interest in the eastern part of the Laurel
                 Field in Jones County, Mississippi in 1993 from Mosbacher
                 Energy, Inc.  Plaintiffs live in a house adjacent to CRI's
                 production facility in that area, and have sued CRI generally
                 claiming contamination, nuisance and other matters.
                 Plaintiffs had sued Mosbacher  in 1991 for these same claims,
                 and Mosbacher settled in 1992, receiving a general release
                 from plaintiffs.  This lawsuit has been settled for a nominal
                 amount ($5,000).

         5.      Luther McCarthy, Administrator of the Estate of Kelvin Dale
                 McCarthy vs. Coho Resources, Inc.  On December 6, 1995, Kelvin
                 McCarthy, employee of Smith Bros., Inc., an independent
                 contractor, was killed when a  workover rig collapsed in the





SCHEDULE 6.01(f), PAGE 1 OF 3
<PAGE>   102
                 Soso Field, Mississippi.  His estate filed an action against
                 CRI for actual damages in the amount of lifetime earnings
                 (present value $470,000), damages under the Mississippi
                 Wrongful Death Act and punitive damages ($3.5 million).  Smith
                 Bros. insurer has agreed to defend the lawsuit on behalf of
                 CRI.

         6.      Bobby Stroo, et ux vs. Coho Resources, Inc.  This is a
                 companion suit to the McCarthy lawsuit.  During the same
                 incident on December 6, 1995 where Mr. McCarthy was killed
                 after a workover rig collapsed in the Soso Field, Mississippi,
                 Mr. Stroo injured his wrist.  He has filed an action against
                 CRI for actual damage in the amount of $2,000,000.00.  CRI's
                 insurer is defending the lawsuit on behalf of CRI.

         7.      Alcus Smith, et al vs. Chevron USA Inc., et al; Hal Ray Owens,
                 et ux vs. Chevron USA Inc. et al.  Both of these lawsuits were
                 filed in early 1996 against CRI and several other companies:
                 Chevron USA Inc. and Florabama/Marjoe Inc., both prior
                 operators of the Brookhaven Field, Lincoln County,
                 Mississippi.  The lawsuits, which are basically identical,
                 involve claims by landlowners for purported damage caused by
                 NORM at various wellsite locations on land leased by CRI.  The
                 plaintiffs are seeking compensatory and punitive damages
                 including damages for the contamination of the land and
                 personal injury to the health of the plaintiffs.

         8.      Gerald Donald vs. Fina Oil & Gas Chemical Company, et al.  In
                 June of 1996 Gerald Donald filed an action against 20 oil
                 companies and a bank for damage to land owned by him in Wayne
                 County, Mississippi.  The damages claim to be contamination of
                 land from disposal operations by an oilfield contractor who
                 was the prior owner of the land.  The field in question is the
                 Eucutta Field, of which Coho owned a small portion and
                 divested to a third party in 1989.  There is no evidence that
                 Coho's operations in any way contributed to the problem
                 claimed by Mr. Donald in regard to contamination of his land.

B.       ING and IN Subsidiaries

         1.      Litigation

                 ARCADIA HOLINESS ASSOCIATION V. IMC CORPORATION, ET AL. (V.
                 MID LOUISIANA GATHERING COMPANY), 15th Judicial District
                 Court, Vermillion Parish, Louisiana Case No. 87-52966.
                 Royalty owners seek asserted underpayment for production
                 produced by IMC Production Company and by Wintershall
                 Corporation/BASF Corporation in excess of $7,000,000.00.  Mid
                 Louisiana Gathering Company has been indemnified by BASF for
                 this.





SCHEDULE 6.01(f), PAGE 2 OF 3
<PAGE>   103
         2.      Asserted Claims

                 L.E. HESTER, JR. ET AL VS. IMC EXPLORATION CO. INC., ET AL
                 (VS. MID LOUISIANA PRODUCTION COMPANY), 4th Judicial District
                 Court, Ouachita Parish, Louisiana, Case No. 96-2616.
                 Overriding royalty owners seek asserted underpayment for
                 production produced by IMC Production Company, Wintershall
                 Energy, and Mid Louisiana Production Company.  Plaintiffs are
                 seeking the sum of $147,613.25 in actual damages.  Mid
                 Louisiana Production Company is of the belief that the leases
                 that are purported to support this claim have expired, and no
                 payments are due.





SCHEDULE 6.01(f), PAGE 3 OF 3
<PAGE>   104
                                SCHEDULE 6.01(m)
                                       to
                          FOURTH AMENDED AND RESTATED
                                CREDIT AGREEMENT


                               CREDIT AGREEMENTS


I.       INTERCOMPANY INDEBTEDNESS

<TABLE>
<CAPTION>
         Debtor                            Lender                            Amount
         ------                            ------                            ------
<S>                                        <C>                               <C>
Coho International Limited                 Coho Resources Limited            $      279,544
Coho International Limited                 Coho Resources Inc.               $    2,674,814
Coho Energy Inc.                           Coho Resources Limited            $       96,897
Coho Resources Limited                     Coho Resources Inc.               $       91,884
Coho Resources Inc.                        Coho Anaguid Inc.                 $      265,000
Coho Resources Inc.                        Coho Marketing & Transportation   $      382,594
Coho Resources Inc.                        Coho Energy Inc.                  $    6,860,957
Coho Resources Inc.                        Interstate Natural Gas Co.        $   22,281,215*
Coho Exploration Inc.                      Coho Resources Inc.               $   27,494,293*
Interstate Natural Gas Co.                 Coho Louisiana Production Co.     $    2,071,305
Interstate Natural Gas Co.                 Coho Fairbanks Gathering Co.      $        1,171
Coho Louisiana Gathering Co.               Coho Louisiana Production Co.     $      348,741
Coho Louisiana Production Co.              Coho Fairbanks Gathering Co.      $      256,895
</TABLE>



II.      GAS PROCESSING PLANT MORTGAGE

         In October, 1994, CRI acquired, from Pronto Gas Co., Inc. ("Pronto") a
         mechanical refrigeration plant and certain vapor recovery units
         intended to extract liquid petroleum products from natural gas
         produced at the Laurel field in Mississippi.  The purchase price was
         $440,000, $100,000 down plus a note for $340,000 due March 1997.  CRI
         is required to make monthly principal and interest payments of
         $12,500.  CRI pledged the plant and 60% of the value of the liquids
         extracted as security for the note.





__________________________________

     *On or before September 8, 1996, these items shall have been evidenced by
subordinated promissory notes in form and substance reasonably acceptable to
the Administrative Agent, or shall have been repaid or recharacterized as
something other than Indebtedness, to the extent permitted by this Agreement.

SCHEDULE 6.01(m), PAGE 1 OF 2
<PAGE>   105
         III.    BROOKHAVEN ACQUISITION

                 In August 1995, CRI acquired from Florabama Associates, Inc.
                 (Florabama) and Seminoil, Inc. (Seminoil) certain oil and gas
                 properties in Brookhaven, Mississippi.  The purchase price was
                 $5,642,000.  To evidence the purchase price, CRI executed
                 promissory notes in the aggregate principal amount of
                 $4,199,566.  Letters of credit totalling $4,199,566.00 were
                 issued to secure such promissory notes.  Of the letters of
                 credit issued, $1,866,846.99 expire 8/28/96 with the balance
                 expiring 8/28/97.





SCHEDULE 6.01(m), PAGE 2 OF 2
<PAGE>   106
                                SCHEDULE 6.01(s)
                                       to
                          FOURTH AMENDED AND RESTATED
                                CREDIT AGREEMENT


                             ENVIRONMENTAL MATTERS


A.       Coho Resources, Inc.


         1.      Agreed Order No. 1615-89 of the Mississippi Commission on
         Environmental Quality, dated August 24, 1989, pursuant to which CRI
         has paid to such Commission the sum of $6,000.00 as full and complete
         settlement of such Commission's proposed citation of CRI for violation
         of Mississippi Code Annotated Section 49-17-29(l)(c) by permitting a
         facility owned by CRI in the Martinville Field to cause pollution in
         an unnamed tributary of the Strong River on or about July 9, 1989.

         2.      Order of Dismissal, dated March 30, 1990, and Settlement
         Agreement and Mutual Release, entered into on March 26, 1990, in the
         litigation matter of B.J. Layton v. Coho Resources, Inc., Cause No.
         9064-8800 in the Circuit Court of the First Judicial District of Hinds
         County, Mississippi, pursuant to which CRI has paid to Mr. B.J. Layton
         the sum of $4,000.00 in settlement of Mr. Layton's complaint alleging
         damages resulting from the presence of drilling fluids and related
         materials in an unnamed tributary of the Strong River on his property
         on or about July 9, 1990.

         3.      Other matters disclosed on the Initial Environmental Report.

         4.      As a result of heavy rainfall, on July 14, 1993, the reserve
         pit at Coho's Country Club location at Laurel, Mississippi overflowed
         causing approximately $44,000 of damage to third parties.  The
         Company's insurance coverage will reimburse Coho for approximately
         $33,000.  The Company was not cited by the Mississippi Commission on
         Environmental Quality.

         5.      On May 25, 1993, CRI had a salt water spill at its Summerland
         field.  Approximately 900 barrels of salt water were spilled.  Of this
         amount, approximately 50% was recovered and disposed.  The remaining
         amount was flushed with fresh water into the Leaf River.  The Company
         was not cited by the Mississippi Commission on Environmental Quality.

         6.      During June and July, 1994, CRI, together with several other
         companies, were named as a defendant in three lawsuits filed in
         Mississippi.  The lawsuits, which are basically identical, involve
         claims by landowners for purported damages caused by naturally
         occurring radioactive materials at various wellsite locations on land
         leased by CRI in Mississippi.  The plaintiffs are seeking compensatory
         and punitive damages, including damages for "emotional distress".





SCHEDULE 6.01(s), PAGE 1 OF 2
<PAGE>   107
         7.      In early 1996 CRI, together with Chevron USA Inc. and
         Florabama/Marjoe Inc., both prior operators, were named as defendants
         in two suits in Brookhaven Field, Lincoln County, Mississippi.  The
         lawsuits deal with purported damage to land caused by the presence of
         NORM at wellsite locations in the field.  The plaintiffs are seeking
         compensatory and punitive damages including damages for contamination
         to the land.

B.       ING and ING Subsidiaries

         1.      In response to natural gas industry concerns, ING and its
         affiliates have voluntarily commenced a program in its production
         areas to remove measurement meters which utilized elemental mercury.
         The program involves the removal and replacement of each mercury meter
         with a newer style bellows meter, and removal of any mercury found on
         the location site of the meter. Over the years, as mercury meters were
         repaired or replaced, a small amount of mercury might occasionally
         escape, falling to the ground.  In connection  with this program, ING
         has worked extensively with the United States Fish and Wildlife
         Services ("USFW") in the D'Arbonne and Upper Ouachita Wildlife Refuges
         located in Northeast Louisiana, where ING through its affiliates have
         approximately 100 mercury meter site locations.  The USFW seeks the
         voluntary removal of the mercury meters from its refuges and the
         cleanup of any mercury which may have spilled.  At this time the USFW
         has only commenced an investigation of its concern, and through
         meetings with the USFW, the Mid Louisiana Production Company has
         reached a tentative agreement, yet to be put in writing, with the USFW
         to address their concerns.  The agreement requires the Production
         Company to remove and replace its approximately 150 mercury meters
         from the refuge areas with bellows meters and to remove any elemental
         mercury that might have been spilled to mutually agreeable levels by
         revolving and replacing the soil underneath each mercury meter
         location which shows the presence of elemental mercury in the soil.  A
         similar program for the remainder of the Production Company's
         operations in the Monroe Gas Field where ING's affiliates operate
         approximately another 1,200 to 1,400 mercury meters will be
         concurrently pursued over the next 5 years.  ING has discussed the
         program with the Louisiana Department of Environmental Quality
         ("LDEQ") for guidance and is in the process of submitting a plan to
         the LDEQ for comment.

         2.      ING/Coho has commenced a remediation operation within the
         refuges specified in Item B.1 above and will have remediated all sites
         on USFW land that have had some spillage of the elemental mercury from
         prior removed mercury meters.  It is anticipated that this process of
         remediation in the D'Arbonne and Upper Ouchita Refuges will be
         completed by the end of September 1996.





SCHEDULE 6.01(s), PAGE 2 OF 2
<PAGE>   108
                                SCHEDULE 6.01(t)
                                       to
                          FOURTH AMENDED AND RESTATED
                                CREDIT AGREEMENT

                            LOCATIONS OF COLLATERAL

1        Chief Executive Office


         14785 Preston Road, Suite 860
         Dallas, Texas 75240

2.       Exact Corporate Name

         Coho Energy, Inc.
         Coho Resources, Inc.
         Interstate Natural Gas Company
         Coho Louisiana Production Company
         Coho Fairbanks Gathering Company
         Coho Louisiana Gathering Company
         Coho Exploration, Inc.

3.       Additional Locations

         Interstate Natural Gas Company

         a.      Secretary of State, Texas

         Coho Louisiana Production Company

         a.      Livingston Parish, LA
         b.      Morehouse Parish, LA
         c.      Ouachita Parish, LA
         d.      Union Parish, LA
         e.      Amite County, MS
         f.      Wilkinson County, MS
         g.      Secretary of State, MS
         h.      Secretary of State, TX


         Coho Fairbanks Gathering Company

         a.      Morehouse Parish, LA
         b.      Ouachita Parish, LA





SCHEDULE 6.01(t), PAGE 1 OF 2
<PAGE>   109
         c.      Union Parish, LA
         d.      Secretary of State, MI
         e.      Secretary of State, TX

         Coho Louisiana Gathering Company

         a.      Morehouse Parish, LA
         b.      Ouachita Parish, LA
         c.      Union Parish, LA
         d.      Secretary of State, MI
         e.      Secretary of State, TX

         Coho Exploration, Inc.

         a.      Simpson County, MS

         Coho Resources, Inc.

         a.      Smith County, MS
         b.      Jones County, MS
         c.      Covington County, MS
         d.      Jasper County, MS
         e.      Simpson County, MS
         f.      Yazoo County, MS
         g.      Madison County, MS
         h.      Perry County, MS





SCHEDULE 6.01(t), PAGE 2 OF 2
<PAGE>   110
                                SCHEDULE 7.02(a)
                                       to
                          FOURTH AMENDED AND RESTATED
                                CREDIT AGREEMENT


                          LIENS SECURING INDEBTEDNESS


1.       Cash deposits securing Indebtedness described on Schedule 6.01(m).

2.       Security Agreement dated October 1, 1994 between CRI and Pronto Gas
         Co., Inc. securing a $340,000 promissory note issued by CRI.  The
         security agreement covers a mechanical refrigeration plant and related
         equipment and 60% of the liquids extracted by the plant.

3.       Letters of Credit dated August 16, 1995, securing promissory notes
         issued by CRI pursuant to that certain Purchase and Sale Agreement
         between CRI and Floribama Associates, Inc. and Seminoil, Inc. dated
         August 9, 1995.  The purchase and sale agreement relates to the
         acquisition of certain oil and gas properties in Brookhaven,
         Mississippi.





SCHEDULE 7.02(a), SOLO PAGE
<PAGE>   111
                                SCHEDULE 7.02(f)
                                       to
                           THIRD AMENDED AND RESTATED
                                CREDIT AGREEMENT


                            AFFILIATED TRANSACTIONS


1.       The Exclusive Territory Agreement entered into by Coho Canada and CRI
which provides that CRI will have the exclusive right to produce, explore and
develop all present and future prospects in the United States, and Coho Canada
will have the exclusive right to conduct such activities outside the United
States.  The Agreement has an initial term that expires on January 1, 1995 and
will continue thereafter until Coho Canada's fully-diluted proportionate voting
interest in CRI falls below 35%.

2.       The Management Services Agreement entered into by Coho Canada and CRI
pursuant to which Coho Canada will provide all senior management and various
services, such as accounting, legal, technical support and administration
service to CRI.  CRI will reimburse Coho Canada for all of its direct costs
incurred in rendering services to CRI under the contract and will pay Coho
Canada for allocated indirect costs incurred in rendering such services.  The
Management Services Agreement provides that CRI will furnish certain services,
such as technical support services, to Coho Canada.  CRI will be reimbursed by
Coho Canada for the direct and indirect expenses of providing such services to
Coho Canada on the same or similar basis.  The Management Services Agreement
has an initial term that expires on January 1, 1995 and will continue
thereafter until terminated by either party upon 180 days' written notice to
the other party.

3.       The Equity Participation Agreement entered into by Coho Canada and CRI
which entitles Coho Canada to participate in any future issuances by CRI of
equity securities at the time of such issuance and on terms equivalent in cash
to those terms being offered to others.  Under the Equity Participation
Agreement, Coho Canada is entitled to acquire equity securities upon their
being issued by CRI (including, among others, issuances in connection with
public offerings, private placements or acquisitions of businesses or assets in
exchange for equity securities) in proportion to Coho Canada's percentage,
calculated on a fully-diluted basis immediately prior to such issuances, of the
total votes that could be cast upon an election of directors of CRI.  Equity
securities include common shares, preferred shares (with or without voting
rights) and securities convertible into or exchangeable for, or options,
warrants or rights to acquire or subscribe for, common shares or preferred
shares (with or without voting rights) of CRI.  The Equity Participation
Agreement terminates when Coho Canada's fully-diluted proportionate voting
interest in the Company falls below 35%.

4.       The Registration Rights Agreement entered into by Coho Canada and CRI,
pursuant to which the Company agreed that, upon the request of Coho Canada, CRI
will register under the Securities Act of 1933 and applicable state securities
laws the sale of the common shares of CRI owned by Coho Canada that Coho Canada
(or certain assignees) has requested to be registered.  Such registration right
will expire on the earlier of 21 years from the date of the proposed public
offering





SCHEDULE 7.02(f), PAGE 1 OF 2
<PAGE>   112
of common shares of CRI and the date on which Coho Canada's fully-diluted
proportionate voting interest in CRI falls below 10%.  CRI's obligation is
subject to certain limitations relating to a minimum amount of common shares of
CRI required for registration, the timing of registration and other similar
matters.  CRI will pay all out-of-pocket expenses in connection with Coho
Canada's initial two exercises of its registration rights under the
Registration Rights Agreement and Coho Canada will pay all expenses in
connection with all subsequent exercises.

5.       The Registration Rights Agreement entered into by Holdings and Mr. Ken
Lambert and Mr. Frederick Campbell whereby upon the request of Mr. Lambert or
Mr. Campbell Holdings will register, on a one-time basis only for each, under
the Securities Act of 1933, and applicable state securities laws the sale of
the common shares of Lambert or Campbell.

6.       The Registration Rights Agreement entered into by Holdings, Morgan
Stanley Leverage Equity Fund II, LP ("Morgan") and Quinn Oil Company Ltd,
("Quinn") whereby upon the request of Morgan or Quinn Holdings will register
under the Securities Act of 1993, and applicable state securities laws, its
sale of common shares of Morgan or Quinn.

7.       The Amended and Restated Registration Rights Agreement entered into by
Holdings and Mr. Ken Lanbert and Mr.  Frederick Campbell.

8.       Holdings has entered into Employment Agreements with Jeffrey Clarke,
R. M. Pearce and E. M. LeBlanc providing for, among other things, severance
payments in the event of termination by Holdings without "cause".

9.       CRI has entered into Executive Severance Agreements with Keri Clarke,
R. Lynn Guillory, Larry L. Keller, Anne Marie O'Gorman and Patrick S. Wright.

10.      In 1990, Holdings made a non-interest bearing loan in the amount of
$205,000.00 to Jeffrey Clarke, President, Chief Executive Officer and Director
of Holdings, to assist him in the purchase of a house in Dallas.  The loan is
unsecured and is repayable on the date Mr. Clarke ceases employment with
Holdings.





SCHEDULE 7.02(f), PAGE 2 OF 2