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                                                                   EXHIBIT 10.24

                           PURCHASE AND SALE AGREEMENT

                                 BY AND BETWEEN

                       CMS OIL AND GAS COMPANY, AS SELLER

                                       AND

                     QUICKSILVER RESOURCES INC, AS PURCHASER

                            EFFECTIVE JANUARY 1, 2000

                               MICHIGAN PROPERTIES


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                                TABLE OF CONTENTS



<TABLE>
<S>                                                                                                   <C>
RECITALS.................................................................................................1
ARTICLE I - SALE AND PURCHASE............................................................................1
   1.1.       Description of Assets......................................................................1
   1.2        Excluded Assets............................................................................4
   1.3        Effective Date and Transfer................................................................4
ARTICLE II - DEFINITIONS.................................................................................5
ARTICLE III - PURCHASE PRICE.............................................................................8
   3.1        Purchase Price.............................................................................8
   3.2        Net Cash Payment to CMS....................................................................8
   3.3        Adjustments to Purchase Price..............................................................8
   3.4        Payment of Adjusted Purchase..............................................................11
   3.5        Over and Under Production.................................................................11
   3.6        Purchase Price Allocation.................................................................12
ARTICLE IV - REPRESENTATIONS OF CMS.....................................................................12
   4.1        Existence.................................................................................12
   4.2        Authorization.............................................................................12
   4.3        Brokers...................................................................................13
   4.4        Noncontravention..........................................................................13
   4.5        Terra Shares..............................................................................13
   4.6        Legal Compliance..........................................................................13
   4.7        Excluded Assets...........................................................................13
   4.8        Environmental, Health and Safety Matters..................................................14
   4.9        Litigation................................................................................14
   4.10       Compliance With Contracts.................................................................14
   4.11       Tax Matters...............................................................................14
   4.12       Compliance With Permits and Licenses......................................................16
   4.13       Title.....................................................................................16
   4.14       Consents, Approvals and Rights to Acquire.................................................16
   4.15       Gas Contracts.............................................................................16
   4.16       Securities Disclosure/Representation......................................................16
ARTICLE V - REPRESENTATIONS OF PURCHASER................................................................17
   5.1        Existence.................................................................................17
   5.2        Execution.................................................................................17
   5.3        Authorization.............................................................................17
   5.4        Brokers...................................................................................17
   5.5        Noncontravention..........................................................................17
   5.6        Independent Evaluation and Title Review...................................................18
   5.7        Securities Disclosure/Representation......................................................18
   5.8        Bonds and Permits.........................................................................18
   5.9        Section 29 Tax Credits....................................................................19
ARTICLE VI - REPRESENTATIONS CONCERNING TERRA...........................................................19
   6.1        Organization, Qualification and Corporate Power...........................................19
   6.2        Capitalization............................................................................19
   6.3        Noncontravention..........................................................................20
   6.4        Subsidiaries and Affiliates...............................................................20
   6.5        Financial Statements......................................................................20
   6.6        Events Subsequent to Most Recent Fiscal Month End.........................................21
   6.7        Legal Compliance..........................................................................21
   6.8        Tax Matters...............................................................................21
   6.9        Powers of Attorney........................................................................24
   6.10       Litigation................................................................................24
   6.11       Employees and Employee Benefits...........................................................25
   6.12       Environmental, Health and Safety Matters..................................................25
   6.13       No Guaranties; Extension of Credit........................................................25
   6.14       Permits...................................................................................25
   6.15       Compliance With Contracts.................................................................26
   6.16       Title.....................................................................................26
   6.17       Consents, Approvals and Rights to Acquire.................................................26
</TABLE>

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<TABLE>
<S>                                                                                                  <C>
   6.18       Gas Contracts.............................................................................26
   6.19       Material Contracts........................................................................26
   6.20       Disclaimer of All Other Representations and Warranties....................................27
ARTICLE VII - OPERATIONS AND CASUALTY LOSS..............................................................27
   7.1        Revenues and Expenses.....................................................................27
   7.2        Operations and Loss of Assets and Terra Assets............................................27
ARTICLE VIII - PRE-CLOSING OBLIGATIONS OF CMS...........................................................30
   8.1        Encumbrances..............................................................................30
   8.2        Approvals/Consents........................................................................30
   8.3        Notices and Consents......................................................................30
   8.4        Operation of Business.....................................................................31
   8.5        Full Access...............................................................................31
   8.6        Notice of Developments....................................................................31
ARTICLE IX - PRE-CLOSING OBLIGATIONS OF PURCHASER.......................................................32
   9.1        Approvals/Consents........................................................................32
   9.2        Bonds and Permits.........................................................................32
   9.3        Corporate Documentation...................................................................33
   9.4        Notices and Consents......................................................................33
   9.5        Notice of Developments....................................................................33
   9.6        Notice of Misrepresentation or Breach of Warranty.........................................33
ARTICLE X - CMS'S CONDITIONS OF CLOSING.................................................................34
   10.1       Representations...........................................................................34
   10.2       Performance...............................................................................34
   10.3       Pending Matters...........................................................................34
   10.4       Waiting Periods...........................................................................34
   10.5       Opinion of Counsel........................................................................34
   10.6       Payment of Purchase Price or Adjusted Purchase Price......................................34
ARTICLE XI - PURCHASER'S CONDITIONS OF CLOSING..........................................................35
   11.1       Representations...........................................................................35
   11.2       Performance...............................................................................35
   11.3       Pending Matters...........................................................................35
   11.4       Waiting Periods...........................................................................35
   11.5       Opinion of Counsel........................................................................35
ARTICLE XII - ENVIRONMENTAL CONDITION...................................................................35
   12.1       Existing Condition........................................................................35
   12.2       Environmental Assessment and Access.......................................................36
   12.3       Release and Indemnity for Environmental Conditions........................................37
   12.4       Confidentiality, Release and Indemnity For Environmental Assessment.......................38
   12.5       Insurance for Environmental Assessment....................................................38
   12.6       Indemnity Regarding Access................................................................39
ARTICLE XIII - TITLE EXAMINATION........................................................................39
   13.1       Title Examination Period..................................................................39
   13.2       Cure of Title.............................................................................40
   13.3       Title Adjustments.........................................................................40
   13.4       Value of Title Adjustments................................................................41
   13.5       Limits on Title Adjustments...............................................................42
   13.6       Definition of Defensible Title............................................................42
   13.7       Definition of Permitted Encumbrances......................................................42
   13.8       Definition of Title Defect................................................................43
   13.9       Back-In Interest Adjustments..............................................................44
   13.10      Representations, Warranties or Covenants, and Indemnity...................................45
   13.11      Arbitration...............................................................................46
ARTICLE XIV - RETAINED LIABILITIES......................................................................46
ARTICLE XV -  CLOSING...................................................................................46
   15.1.      Time and Place of Closing.................................................................46
   15.2       Closing Obligations.......................................................................46
   15.3       Suspended Accounts........................................................................48
   15.4       Termination of Guarantees and Other Commitments...........................................49
ARTICLE XVI - CONTINUING OBLIGATIONS....................................................................49
   16.1       Post-Closing Reconciliation...............................................................49
   16.2       Receipts and Credits......................................................................49
   16.3       Assumption of Obligations and Indemnities.................................................51
</TABLE>


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<TABLE>
<S>                                                                                                    <C>
   16.4       Recording.................................................................................53
   16.5       State of Michigan Oil and Gas Leases......................................................53
   16.6       Further Assurances........................................................................53
   16.7       Records...................................................................................54
   16.8       Access to Records.........................................................................54
   16.9       Litigation Support........................................................................54
   16.10      CMS Employees.............................................................................54
   16.11      Transition................................................................................54
   16.12      Plan B....................................................................................55
ARTICLE XVII - TERMINATION..............................................................................55
   17.1       Right of Termination......................................................................55
   17.2       Liabilities Upon Termination or Failure to Close..........................................56
   17.3       Deposit...................................................................................57
   17.4       Effect of Termination.....................................................................57
ARTICLE XVIII - REMEDIES FOR BREACHES OF THIS AGREEMENT.................................................58
   18.1       Survival of Representations and Warranties................................................58
   18.2       Indemnification Provisions for Benefit of the Purchaser...................................58
   18.3       Indemnification Provisions for Benefit of CMS.............................................59
   18.4       Matters Involving Third Parties...........................................................59
   18.5       Determination of Adverse Consequences.....................................................60
   18.6       Exclusive Remedy..........................................................................60
ARTICLE XIX - TAXES.....................................................................................60
   19.1       Liability for Taxes.......................................................................60
   19.2       Tax Returns...............................................................................61
   19.3       Contest Provisions........................................................................62
   19.4       Assistance and Cooperation................................................................62
   19.5       Adjustment to Purchase Price For Taxes....................................................63
   19.6       Treatment of the Terra Shares.............................................................63
   19.7       CMS Tax Allocation Agreement..............................................................63
   19.8       Books and Records.........................................................................63
   19.9       Sales Taxes...............................................................................64
   19.10      Other Taxes...............................................................................64
ARTICLE XX - EXERCISE OF PREFERENTIAL PURCHASE RIGHTS...................................................64
ARTICLE XXI - INDEPENDENT INVESTIGATION AND DISCLAIMER..................................................65
   21.1       Disclaimer as to Warranties...............................................................65
   21.2       Disclaimer As To Year 2000 Compliance.....................................................65
ARTICLE XXII - MISCELLANEOUS............................................................................66
   22.1       Like-Kind Exchange........................................................................66
   22.2       Governing Law.............................................................................66
   22.3       Entire Agreement..........................................................................66
   22.4       Amendments and Waivers....................................................................66
   22.5       Captions..................................................................................67
   22.6       Assignment................................................................................67
   22.7       Notices...................................................................................67
   22.8       Expenses..................................................................................68
   22.9       Severability..............................................................................68
   22.10      Confidentiality, Publicity and Retention of Data..........................................68
   22.11      Use of CMS's Name.........................................................................69
   22.12      Conditions................................................................................69
   22.13      No Third-Party Beneficiaries..............................................................69
   22.14      Succession and Assignment.................................................................69
   22.15      Construction..............................................................................69
   22.16      Attachments...............................................................................69
   22.17      Counterparts..............................................................................69
   22.18      Execution Deadline........................................................................70
ATTACHMENT A1
ATTACHMENT A2
ATTACHMENT A3
ATTACHMENT A4
ATTACHMENT A5
ATTACHMENT B1
ATTACHMENT B2
</TABLE>

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ATTACHMENT B3
ATTACHMENT C
ATTACHMENT D
ATTACHMENT E
ATTACHMENT F
ATTACHMENT G
ATTACHMENT H
ATTACHMENT I
ATTACHMENT J
ATTACHMENT K
ATTACHMENT L
ATTACHMENT M
ATTACHMENT N
ATTACHMENT O
ATTACHMENT P
ATTACHMENT Q
ATTACHMENT R
ATTACHMENT S
ATTACHMENT T


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                           PURCHASE AND SALE AGREEMENT

         THIS PURCHASE AND SALE AGREEMENT (this "Agreement") is made as of the
4th day of March, 2000, by and between CMS OIL AND GAS COMPANY, a Michigan
corporation ("CMS"), whose address is 1021 Main Street, Suite 2800, Houston,
Texas 77002, and QUICKSILVER RESOURCES INC., a Delaware corporation
("Purchaser"), whose address is 1619 Pennsylvania Avenue, Fort Worth, Texas
76104. CMS and the Purchaser may hereinafter be referred to collectively as the
"Parties" and individually as a "Party".

                                    RECITALS

         WHEREAS, CMS desires to sell and Purchase desires to purchase the
Assets, as hereinafter defined, on the terms and conditions provided in this
Agreement;

         NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are acknowledged by both Parties, CMS and Purchaser hereby
agree as follows:

                          ARTICLE I - SALE AND PURCHASE

1.1.     DESCRIPTION OF ASSETS

         At the Closing (as defined in Section 15.1, below), CMS shall sell and
Purchaser shall purchase, as hereinafter provided, as of the Effective Date, the
following assets (the "Assets"):

         (a)      All of CMS's right, title and interest in and to all of the
                  issued and outstanding capital stock of Terra Energy Ltd., a
                  Michigan corporation ("Terra");

         (b)      All of CMS's and Terra's right, title and interest in and to
                  the wells and units described at Attachment A1, the oil and
                  gas leases described at Attachment A2, the overriding
                  royalties described at Attachment A3 and the fee mineral, fee
                  surface and real property interests and right of ways
                  described at Attachment A4, all of which Attachments are
                  attached hereto and made a part hereof and are hereinafter
                  collectively referred to as Attachment A (including, but not
                  limited to any working interest, leasehold rights, royalty
                  interests, overriding royalty interests and reversionary
                  rights held as of the Effective Date) but excepting, however,
                  the Excluded Assets as defined below;

         (c)      All of CMS's and Terra's corresponding right, title and
                  interest in and to all oil and gas wells, injection wells,
                  disposal wells, water wells, surface and downhole equipment,
                  personal property, structures, fixtures, flowlines, pipelines
                  and pumps to the extent used or held for use in connection
                  with the exploration, development, operation or maintenance of
                  the assets described at Attachment A1, Attachment A2,
                  Attachment A3 and Attachment A4, including, but not limited
                  to, the gas plants, compressors, facilities, systems and
                  pipelines described at Attachment A5 hereto, but excepting,
                  however, the Excluded Assets as defined below;



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         (d)      All of CMS's and Terra's corresponding right, title and
                  interest in easements, rights-of-way, permits, licenses,
                  surface leases and use agreements, servitudes and other
                  surface rights appurtenant to the assets, to the extent the
                  same are assignable, and to the extent now being used or held
                  for use in connection with the exploration, development,
                  operation and maintenance of the assets, but excepting,
                  however, the Excluded Assets as defined below, (the interest
                  of CMS in all of the items listed in Section 1.1(b) and
                  Section 1.1(c), above, this Section 1.1(d), and at Attachment
                  A, shall occasionally be hereinafter collectively referred to
                  as the "Subject Property");

         (e)      All of CMS's corresponding right, title and interest in and to
                  and under or derived from all presently existing and currently
                  effective unitization, pooling and communitization agreements,
                  declarations and orders (including, but not limited to, all
                  units formed under orders, regulations, rules or other
                  official actions of any federal, state or other governmental
                  agency having jurisdiction) to which the Subject Property (or
                  any part thereof) are committed, and all privileges, benefits
                  and powers, appurtenant thereto;

         (f)      All of CMS's corresponding right, title and interest in all
                  oil and gas and other hydrocarbons produced from or (if
                  unitized, pooled or communitized with other leases or lands)
                  allocable to the Subject Property after the Effective Date;

         (g)      All of CMS's corresponding right, title and interest in and to
                  or derived from all presently existing and effective oil,
                  natural gas and gas liquid purchase, processing and sales
                  contracts, (but specifically excepting and excluding the
                  Natural Gas Purchase Agreement effective May 1, 1989, by and
                  between Midland Cogeneration Venture Limited Partnership and
                  Northern Michigan Exploration Company and CMS Energy
                  Corporation), operating agreements, farmin or farmout
                  agreements, and other contracts (but not including any bonds
                  held by CMS or its parent, subsidiary or affiliate entities
                  for CMS's benefit), agreements and instruments to the extent
                  directly related to the Subject Property and the exploration
                  or development of oil and gas (or either of them) from or
                  attributable to the Subject Property, only to the extent the
                  same are assignable, but excepting, however, the Excluded
                  Assets as defined below; and

         (h)      Subject to Section 16.7, originals, or in the sole discretion
                  of CMS, copies of the following files, records and data of
                  CMS, to the extent directly related to the Subject Property:
                  lease files, well files, unit files, division order files,
                  lease contract files, geological and geophysical data, legal
                  files, and tax records and FERC filings related to section 29
                  non-conventional fuels tax credits, and subject to Section
                  16.7 and Section 19.8, all of the files, records and data of
                  Terra. This agreement by CMS to convey and deliver the
                  aforementioned files, records and data is granted by CMS to
                  the extent that CMS or Terra has authority to do so without
                  violating any confidentiality obligation to a third party, and
                  is without warranty as to the accuracy or completeness of the
                  information delivered. Any other provision of this Agreement
                  to the contrary notwithstanding, CMS shall not provide
                  Purchaser with any files, records or data or access to any
                  files, records or data which (i) are not in the possession or
                  control of CMS or Terra, (ii) CMS considers to be



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                  privileged, proprietary or confidential to it and which are
                  not directly related to the condition, quantity and quality of
                  the Assets, (iii) CMS or Terra cannot legally provide
                  Purchaser because of third party restrictions on CMS or Terra,
                  or disclosure of which will violate any agreement to which CMS
                  or Terra is a party, (iv) are a part of or relate solely to
                  the Excluded Assets, or (v) relate exclusively to Retained
                  Liabilities (as defined below).

              It is CMS's intent to sell to Purchaser, and it is Purchaser's
              intent to purchase from CMS, all of CMS's right, title and
              interest in and to the Assets, regardless of whether the Assets
              are incompletely or incorrectly described on the Attachments
              hereto, but specifically excepting, however, the Excluded Assets
              as defined below. In order to fully and completely effectuate the
              intent of the Parties, CMS further agrees to assign and convey,
              and Purchaser further agrees to accept and assume, at any time
              whether at Closing or post-Closing, any and all assets,
              obligations and liabilities of CMS related thereto, of CMS of the
              kind described in (a) - (h), above, which are located in the state
              of Michigan, and which are not included at Attachment A, saving
              and excepting the Excluded Assets.

              The Parties further acknowledge that the references to "Terra",
              and its right, title and interest in and to the assets referenced
              in Section 1.1(b), Section 1.1(c) and Section 1.1(d), above, are
              included in those sections, and at Attachment A, for
              identification purposes only. For purposes of this Agreement the
              right, title and interest of Terra in and to these assets shall
              not be deemed to be Assets, except insofar as ownership of these
              items follows the ownership of all of the outstanding capital
              stock of Terra as referenced in Section 1.1(a), above.

              All of the right, title and interest of Terra in and to all assets
              described at Attachment A, shall cumulatively hereinafter be
              referred to as the "Terra Property". The Terra Property, as well
              as Terra's corresponding right, title and interest (i) in and to
              and under or derived from all presently existing or currently
              effective unitization, pooling and communitization agreements,
              declarations and orders (including, but not limited to, all units
              formed under orders, regulations, rules or other official actions
              of any federal, state or other governmental agency having
              jurisdiction) to which the Terra Assets (or any part thereof) are
              committed and all privileges, benefits and powers appurtenant
              thereto, (ii) in all oil and gas and other hydrocarbons produced
              from or (if unitized, pooled or communitized with other leases or
              lands) allocable to the Terra Property, after the Effective Date,
              (iii) in all presently existing and effective oil, natural gas and
              gas liquid purchase, processing and sales contracts, operating
              agreements, farmin or farmout agreements and other contracts,
              agreements and instruments directly related to the Terra Property,
              and the exploration or development of oil and gas (or either of
              them) from or attributable to the Terra Property, above, and (iv)
              subject to Section 16.7 and Section 19.8, and further subject to
              the limitations set forth in Section 1.1(h), above, in all lease
              files, well files, unit files, lease contract files, geophysical
              data, financial records, corporate records, legal files, computer
              programs, general tax records, samples, test data or any other
              records, samples, information, data or documents of Terra, but
              excepting, however, the Excluded Assets as defined below, shall
              cumulatively hereinafter be referred to as the "Terra Assets".




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              Purchaser shall accept and assume all burdens and liabilities
              past, present and future with respect to the Assets and the Terra
              Assets, excepting, however, the Retained Liabilities, as defined
              and identified below.

              The Parties acknowledge that certain of the Assets and the Terra
              Assets may be subject to third party preferential rights to
              purchase, rights of reconveyance, consents to sell or assign or
              confidentiality agreements, and nothing in this Section 1.1 shall
              be deemed to constitute a representation or warranty that the
              Assets or the Terra Assets are free and clear of any preferential
              rights, rights of reconveyance, consents or confidentiality
              agreements.

1.2      EXCLUDED ASSETS

         This Agreement does not cover, and any instrument of conveyance or
assignment made pursuant to Section 15.2, below, of this Agreement shall except
and exclude the Excluded Assets. Excluded Assets shall include: (i) the items
that are described at Attachment B1, (ii) the real property, building and
appurtenances commonly known as, and located at 1475 Terra Road, Traverse City,
Michigan as described at Attachment B2, and all fixtures and personal property
located thereon which is not specifically covered in Section 1.1, above, (iii)
the wells, units and leases described at Attachment B3 and all Assets or Terra
Assets insofar as they are used or held for use in connection therewith, (iv)
the Natural Gas Purchase Agreement (effective May 1, 1989) between Midland
Cogeneration Venture Limited Partnership and Northern Michigan Exploration
Company and CMS Energy Corporation and (v) Terra's interest in Thunder Bay
Pipeline Co., LLC. The term Excluded Assets shall also be deemed to include all
items of property, including but not limited to vehicles, tools, machines,
warehouse stock, equipment, materials, pipelines, fixtures, facilities and
interests which are leased by CMS, or as to which CMS has only a license or
other right of use, and any items of property, including but not limited to
vehicles, tools, machines, warehouse stock, equipment, materials, pipelines,
fixtures, facilities and interests which are owned by third parties, such as
employees, contractors or agents, even if such items of property are used or
held for use in connection with the Assets or the Terra Assets.

1.3      EFFECTIVE DATE AND TRANSFER

         For the purposes of this Agreement, the phrase "Effective Date" shall
mean 7:00 o'clock, A.M. local time (where the Assets and the Terra Assets are
located) on January 1, 2000. Unless otherwise provided within this Agreement for
a specific property(s), the phrase "Transfer Date" shall mean 7:00 o'clock A.M.
local time on the next ensuing day after Closing. On the Transfer Date CMS,
subject to Section 7.2, Section 13.10, and Section 15.2(k) hereof, shall
transfer to Purchaser, and Purchaser shall accept the physical, possession,
control, responsibility and, subject to Section 7.2, operations of the portions
of the Assets and the Terra Assets which are operated by CMS or Terra. Nothing
contained in this Section 1.3, or in this Agreement generally, shall be deemed
to be a representation or warranty of CMS that Purchaser is entitled to, nor
that Purchaser will succeed CMS or Terra as operator, nor that Terra shall be
entitled to remain as operator of all or any portion of the Subject Property or
the Terra Property now operated by CMS or Terra.



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                            ARTICLE II - DEFINITIONS

2.1 "Accredited Investor" has the meaning set forth in Regulation D promulgated
under the Securities Act.

2.2 "Adverse Consequences" means all actions, suits, proceedings, hearings,
investigations, charges, complaints, claims, demands, injunctions, judgments,
orders, decrees, rulings, damages, dues, penalties, fines, costs, reasonable
amounts paid in settlement, liabilities, obligations, taxes, liens, losses,
expenses, and fees, including court costs and reasonable attorneys' fees and
expenses.

2.3 "Affiliate" or "Affiliates" means any entity, including any corporation or
limited liability company with respect to which a specified Person owns less
than a majority of the common stock or less than a majority of the ownership
interest of the entity.

2.4 "Assets" has the meaning set forth in Section 1.1, above.

2.5 "CMS Disclosure Schedule" has the meaning set forth in Article IV, below.

2.6 "Cash" means cash and cash equivalents (including marketable securities and
short term investments) calculated in accordance with GAAP applied on a basis
consistent with the preparation of the Financial Statements.

2.7 "Claim of Title Defect" has the meaning set forth in Section 13.1, below.

2.8 "Claims" means, with respect to the agreement of any Party to defend,
indemnify and hold harmless another Party, any and all claims, suits, causes of
action, demands, liabilities, judgments, fines, penalties, damages, losses,
expenses or costs, including without limitation court costs and legal and
accounting fees and expenses, arising out of, in respect of or in any manner
related to the subject of such agreement.

2.9 "Closing" has the meaning set forth in Section 15.1, below.

2.10 "Closing Date" has the meaning set forth in Section 15.1, below.

2.11 "Closing Statement" has the meaning set forth in Section 15.2(e), below.

2.12 "Code" means the Internal Revenue Code of 1986, as amended.

2.13 "Confidential Information" means any information concerning the businesses
and affairs of CMS and Terra, and their Subsidiaries and Affiliates that is not
already generally available to the public.

2.14 "Defensible Title" has the meaning set forth in Section 13.6, below.

2.15 "Effective Date" has the meaning set forth in Section 1.3, above.

2.16 "Employee Benefit Plan" means any (a) nonqualified deferred compensation or
retirement plan or arrangement, (b) qualified defined contribution retirement
plan or arrangement which is an Employee Pension Benefit Plan, (c) qualified
defined benefit retirement plan or arrangement which is an Employee Pension
Benefit Plan (including any Multiemployer Plan),


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<PAGE>   11

or (d) Employee Welfare Benefit Plan or material fringe benefit or other
retirement, bonus, or incentive plan or program.

2.17 "Employee Pension Benefit Plan" has the meaning set forth in ERISAss.3 (2).

2.18 "Employee Welfare Benefit Plan" has the meaning set forth in ERISAss.3 (1).

2.19 "Environmental Assessment" has the meaning set forth in Section 12.2,
below.

2.20 "Environmental, Health, and Safety Requirements" shall mean all federal,
state and local statutes, regulations, and ordinances concerning public health
and safety, worker health and safety, and pollution or protection of the
environment, including without limitation all those relating to the presence,
use, production, generation, handling, transportation, treatment, storage,
disposal, distribution, labeling, testing, processing, discharge, release,
threatened release, control, or cleanup of any hazardous materials, substances
or wastes, as such requirements are enacted and in effect on or prior to the
Effective Date.

2.21 "ERISA" means the Employee Retirement Income Security Act of 1974, as
amended.

2.22 "Excluded Assets" has the meaning set forth in Section 1.2, above.

2.23 "Extended Due Diligence Period" has the meaning set forth in Section 13.1,
below.

2.24 "Financial Statements" has the meaning set forth in Section 6.5, below.

2.25 "GAAP" means United States generally accepted accounting principles as in
effect from time to time.

2.26 "Income Tax" means any federal, state or local income tax, including any
interest, penalty, or addition thereto, whether disputed or not.

2.27 "Income Tax Return" means any return, declaration, report, claim for
refund, or information return or statement relating to Income Taxes, including
any schedule or attachment thereto.

2.28 "Indemnified Party" has the meaning set forth in Section 18.4(a), below.

2.29 "Indemnifying Party" has the meaning set forth in Section 18.4(a), below.

2.30 "Interim Period" has the meaning set forth in Section 3.3(b), below.

2.31 "Knowledge" means actual knowledge without independent investigation; and
when used in connection with CMS or Terra shall mean actual knowledge of an
officer of CMS without independent investigation.

2.32 "Most Recent Financial Statements" has the meaning set forth in Section
6.5, below.

2.33 "Most Recent Fiscal Month End" has the meaning set forth in Section 6.5,
below.




                                       6
<PAGE>   12

2.34 "Multiemployer Plan" has the meaning set forth in ERISA ss.3 (37).

2.35 "Ordinary Course of Business" means the ordinary course of business
consistent with past custom and practice (including with respect to quantity and
frequency).

2.36 "Over and Under Production" has the meaning set forth in Section 3.5,
below.

2.37 "Party" or "Parties" has the meaning set forth in the preface above.

2.38 "Permits" has the meaning set forth in Section 6.14, below.

2.39 "Person" means an individual, a partnership, a corporation, a limited
liability company, an association, a joint stock company, a trust, a joint
venture, an unincorporated organization, or a governmental entity (or any
department, agency, or political subdivision thereof).

2.40 "Purchase Price" has the meaning set forth in Section 3.1, below.

2.41 "Qualifying Wells" means those wells whose production qualifies for the
credit for producing fuel from nonconventional sources under section 29 of the
Code. The CMS and Terra Qualifying Wells are listed at Attachment C.

2.42 "QRI Stock" has the meaning set forth in Section 3.4(a), below.

2.43 "Retained Liabilities" means those liabilities relating to the Assets or
the Terra Assets, which arise out of events which occurred prior to the
Effective Date and as to which CMS expressly agrees to retain all liability or
to indemnify Purchaser as to all liability. All Retained Liabilities are
identified at Attachment D to this Agreement.

2.44 "Securities Act" means the Securities Act of 1933, as amended.

2.45 "Security Interest" means any mortgage, pledge, lien, encumbrance, charge,
or other security interest, other than (a) mechanic's, materialmen's, and
similar liens, (b) liens for taxes not yet due and payable or for taxes that the
taxpayer is contesting in good faith through appropriate proceedings, (c)
purchase money liens and liens securing rental payments under capital lease
arrangements, and (d) other liens arising in the Ordinary Course of Business and
not incurred in connection with the borrowing of money.

2.46 "Subject Property" has the meaning set forth in Section 1.1(d), above.

2.47 "Subsidiary" or "Subsidiaries" means any entity, including any corporation
or limited liability company with respect to which a specified Person (or a
Subsidiary thereof) owns a majority of the common stock or has the power to vote
or direct the voting of sufficient securities or ownership interest in the
entity to elect or appoint a majority of the directors, or managers.

2.48 "Tax" (and, with correlative meaning, "Taxes" and "Taxable") shall mean (i)
any federal, state or local net income, gross income, single business tax, gross
receipts, windfall profits, severance, property, production sales, use, value
added, license, excise, franchise, employment, payroll, withholding, alternative
or add-on minimum, ad valorem, transfer, excise, stamp, or environmental tax, or
any other tax, custom, duty, governmental fee or import or export duty or other
like assessment or charge of any kind whatsoever, together with any interest or
penalty, addition to


                                       7

<PAGE>   13


tax or additional amount imposed by any governmental authority, and (ii)
liability of CMS, Terra or its Subsidiaries for the payment of amounts with
respect to payments of a type described in clause (i) as a result of being a
member of an affiliated, consolidated, combined or unitary group, or as a result
of any obligation of CMS, Terra or its Subsidiaries under any tax sharing
arrangement or Tax indemnity arrangement.

2.49 "Tax Return" shall mean any return, report or similar statement required to
be filed with respect to any Tax (including any attached schedules), including,
without limitation, any information return, claim for refund, amended return and
declaration of estimated Tax.

2.50 "Terra Assets" has the meaning set forth in Section 1.1, above.

2.51 "Terra Disclosure Schedule" has the meaning set forth in Article VI, below.

2.52 "Terra Property" has the meaning set forth in Section 1.1, above.

2.53 "Terra Shares" means all of the issued and outstanding shares of Common
Stock of Terra.

2.54 "Third Party Claim" has the meaning set forth in Section 18.4(a), below.

2.55 "Title Defect" has the meaning set forth in Section 13.8, below.

2.56 "Transfer Date" has the meaning set forth in Section 1.3, above.

                          ARTICLE III - PURCHASE PRICE

3.1     PURCHASE PRICE

         CMS and Purchaser agree that on and subject to the terms of this
Agreement, the purchase price for the Assets shall be the sum of one hundred
sixty-three million seven hundred ten thousand six hundred twenty-five United
States dollars ($163,710,625) (the "Purchase Price"), plus or minus the
adjustments provided for in Section 3.3,below.

3.2     NET CASH PAYMENT TO CMS

         Immediately prior to the Closing, CMS will cause Terra to pay CMS an
aggregate amount (and may cause each Subsidiary and Affiliate of Terra to pay to
Terra any necessary component thereof) equal to the consolidated Cash of Terra
and its Subsidiaries and Affiliates as of the Closing Date. CMS may cause (i)
Terra to make any such payment to CMS in the form of a dividend or a redemption
and (ii) any Subsidiary or Affiliate of Terra to make any such payment to Terra
in the form of a dividend, a redemption, or an intercompany loan.

3.3     ADJUSTMENTS TO PURCHASE PRICE

        The Purchase Price for the Assets shall be adjusted at Closing as
follows (the "Adjusted Purchase Price"):

         (a)      an adjustment will be made based on the difference between the
                  average bid and offer for a five (5) year term for wholesale
                  natural gas delivered to the Michigan City gate as quoted by
                  Amerex, (the "five-year strip price"), as of January 7, 2000


                                       8
<PAGE>   14


                  (being $2.625/MMBtu), and the average five-year strip price
                  for the five (5) business days ending March 24, 2000 ("Average
                  Five-Year Strip Price"). If the Average Five-Year Strip Price
                  is $2.70/MMBtu or less, or is $2.55/MMBtu or more, then there
                  shall be no adjustment to the Purchase Price. If the Average
                  Five-Year Strip Price is greater than $2.70/MMBtu, or is less
                  than $2.55/MMBtu, the Purchase Price shall be ratably adjusted
                  in proportion to the respective increase over $2.70/MMBtu or
                  decrease under $2.55/MMBtu against $2.625/MMBtu. By way of
                  example, if the Average Five-Year Strip Price is $2.75/MMBtu,
                  assuming a Purchase Price of $163,000,000, then the Purchase
                  Price would be approximately $166,000,000.00 ($2.675 divided
                  by $2.625 multiplied by $163,000,000.00). If the Average
                  Five-Year Strip Price is $2.50/MMBtu, assuming a Purchase
                  Price of $163,000,000, then the Purchase Price would be
                  approximately $159,900,000.00 ($2.575 divided by $2.625
                  multiplied by $163,000,000.00). Notwithstanding the foregoing,
                  in no event shall the Purchase Price be adjusted by more than
                  $7,000,000 as a result of an increase or decrease in the
                  Average Five-Year Strip Price. The foregoing shall be the
                  first adjustment made to the Purchase Price;

         (b)      by adding the amount (based on CMS's good faith estimate) of
                  all expenditures made by CMS or Terra that are attributable to
                  the Assets transferred to Purchaser, and the Terra Assets, for
                  the period between the Effective Date and the Closing Date
                  (the "Interim Period"), including, without limitation,
                  royalties, rentals, operating expenses, overhead charges
                  (which, except as expressly provided in this Agreement, shall
                  not exceed the overhead charges provided for in any applicable
                  operating agreement), all charges billed under operating
                  agreements (such as, but not limited to, CMS's and Terra's
                  share of overhead charges), and all prepaid expenses. All
                  amounts so added to the Purchase Price pursuant to this
                  Section 3.3(b), shall be further adjusted to reflect the
                  actual amount of all such charges and expenses, as part of,
                  and in accordance with the post-closing reconciliation
                  provided for in Section 16.1, below;

         (c)      by adding the value of all merchantable oil in storage above
                  the pipeline connection at the Effective Date that is credited
                  to the Subject Property transferred to Purchaser and the Terra
                  Property. The value of such oil shall be the most current
                  price received by CMS or Terra as of the Effective Date, less
                  taxes deducted by the purchaser of oil, adjusted for BS&W,
                  temperature and quality per the most current sample
                  measurement for the applicable storage tank, to the extent not
                  accounted for in Section 3.3(p), below;

         (d)      by adding the value of all gas produced for which the proceeds
                  have not been received, attributable to production from the
                  Subject Property and the Terra Property for all periods prior
                  to the Effective Date. The value of such gas shall be the most
                  current price received by CMS or Terra as of the Effective
                  Date, less all third party costs deducted by the transporter
                  or purchaser of such gas, to the extent not accounted for in
                  Section 3.3(p), below;

         (e)      by adding the value of all receivables and all other net
                  income of any kind or nature (including but not limited to
                  overhead charges) attributable to the Terra Assets, relating
                  to all periods prior to the Effective Date, whether from or
                  attributable


                                       9
<PAGE>   15

                  to hydrocarbon production, or otherwise, and regardless of
                  when invoiced, collected and received, to the extent not
                  accounted for in Section 3.3(p), below;

         (f)      by subtracting the amount of proceeds received by CMS or Terra
                  that are attributable to hydrocarbon production from the
                  Subject Property and the Terra Property after the Effective
                  Date, net of any royalties, overriding royalties and other
                  payments out of production, and of any production, severance
                  or sales taxes, and all third party costs not reimbursed to
                  CMS or Terra by the transporter or purchaser of production;

         (g)      by adding the value of all pre-paid royalties and severance
                  tax relating to production attributable to the Assets and the
                  Terra Assets, from and after the Effective Date;

         (h)      by subtracting an amount equal to the value of that portion of
                  the Subject Property and the Terra Property, determined
                  pursuant to Article XX ("Exercise of Preferential Purchase
                  Rights") with respect to which preferential purchase rights
                  have been properly and timely exercised by third parties;

         (i)      by adding the amount of accrued interest on the Deposit
                  pursuant to Section 3.4(a), below;

         (j)      an adjustment may also be made to the Purchase Price pursuant
                  to Section 3.5 ("Over and Under Production");

         (k)      an adjustment may also be made to the Purchase Price pursuant
                  to Article VII ("Operations and Casualty Loss");

         (l)      an adjustment may also be made to the Purchase Price pursuant
                  to Section 12.2(d) ("Environmental Assessment and Access");

         (m)      an adjustment may also be made to the Purchase Price pursuant
                  to Article XIII ("Title Examination");

         (n)      an adjustment may also be made to the Purchase Price pursuant
                  to Section 18.5 ("Determination of Adverse Consequences");

         (o)      an adjustment may also be made to the Purchase Price pursuant
                  to Section 19.5 ("Adjustment to Purchase Price for Taxes"), to
                  the extent not accounted for in Section 3.3(q), below;

         (p)      an adjustment will be made to the Purchase Price to account
                  for Terra's consolidated net working capital as of the
                  Effective Date, determined in accordance with Attachment E;

         (q)      by subtracting the dollar amount which is the product of (i)
                  the amount of section 29 tax credit qualified gas (expressed
                  in MMBtus) that constitutes Assets or Terra Assets and which
                  is produced within the Interim Period; and (ii) the tax credit
                  rate (expressed in dollars per MMBtu), as adjusted by
                  inflation for the year 2000 based upon the same percentage
                  increase in inflation for the calendar year 1999 as determined
                  by the Internal Revenue Service, all as provided for by
                  section 29 of the Code; and

         (r)      by adding or subtracting any other amounts mutually agreed
                  upon in writing by the Parties.



                                       10
<PAGE>   16

3.4      PAYMENT OF ADJUSTED PURCHASE

         The Adjusted Purchase Price shall be paid as follows:

         (a)      Unless previously tendered, upon execution and return of this
                  Agreement to CMS, Purchaser shall contemporaneously tender to
                  CMS an earnest money performance deposit (the "Deposit"),
                  consisting of: (i) three million six hundred fifty thousand
                  (3,650,000) fully non-assessable shares of unregistered
                  Quicksilver Resources Inc. common stock, free and clear of any
                  and all claims, liens and encumbrances of any kind,
                  whatsoever, newly and validly issued in the name of CMS ("QRI
                  Stock"), valued at $4.00 per share, and (ii) the sum of one
                  million four hundred thousand dollars ($1,400,000.00) in
                  United States currency. Subject to receipt of the prior
                  written consent of Joint Energy Development Investments
                  Limited Partnership, a Delaware limited partnership ("JEDI"),
                  as required by the terms of a Registration Rights Agreement,
                  dated as of April 9, 1998, between Purchaser and JEDI,
                  Purchaser and CMS shall enter into a Registration Rights
                  Agreement substantially in the form of Attachment F hereto
                  pursuant to which Purchaser shall agree to register the QRI
                  Stock on the terms and subject to the conditions set forth
                  therein. Purchaser agrees to use its commercially reasonable
                  best efforts to obtain the consent of JEDI referred to above
                  as soon as possible following the execution and return of this
                  Agreement. At Closing, CMS shall return the QRI Stock to
                  Purchaser in exchange for United States currency equal to
                  fourteen million six hundred thousand dollars ($14,600,000.00)
                  in United States currency, plus interest thereon at the rate
                  of eight percent (8%) per annum computed from and after
                  February 15, 2000, to the Closing Date, and in no event shall
                  such interest be credited against the Purchase Price or the
                  Adjusted Purchase Price. In the event that the transaction
                  contemplated by this Agreement does not close, then and in
                  that event the ultimate disposition of the Deposit, and the
                  terms and conditions thereof, shall be governed by the
                  provisions of Section 17.3, below;

         (b)      At Closing, Purchaser shall pay to CMS, by bank wire transfer
                  in United States currency either the Purchase Price or
                  Adjusted Purchase Price as reflected on the Closing Statement
                  referenced in Section 15.2(e), to be mutually agreed upon at
                  least one (1) business day prior to the Closing Date, or
                  failing such mutual agreement, the Adjusted Purchase Price, in
                  a manner specified by CMS prior to Closing. In either event
                  all further adjustments to the Purchase Price will be
                  reconciled in accordance with Section 16.1, below.

3.5      OVER AND UNDER PRODUCTION

         For purposes of this Agreement, the term "Over and Under Production"
shall mean as of the Effective Date the difference between the volume of
produced gas that CMS or Terra took from any portion of the Subject Property or
the Terra Property, and the volume of CMS's or Terra's gas entitlement for such
Property or Terra Property, and shall also include all gas plant and pipeline
imbalances.

         (a)      CMS's current estimate of all Over and Under Production are
                  set forth at Attachment G hereto (as of the dates set forth
                  therein).



                                       11
<PAGE>   17


         (b)      At Closing, CMS will furnish Purchaser with a statement
                  showing the most current estimate of the Over or Under
                  Production as of the most recent date available. From and
                  after the Effective Date any and all benefits, obligations and
                  liabilities associated with Over and Under Production shall
                  accrue to and be the responsibility of Purchaser. Purchaser
                  shall assume CMS's and Terra's overproduced and underproduced
                  positions as of the Effective Date, including but not limited
                  to the responsibility for the payment of royalties and other
                  burdens, and all Taxes on the volume of such gas which CMS or
                  Terra took in excess of its entitlement and any obligation to
                  balance, whether in cash or in kind. The Section 3.3
                  Adjustments to the Purchase Price, and/or the Section 16.1
                  Final Settlement Statement shall include an adjustment for any
                  Over and Under Production existing as of the Effective Date.
                  All production imbalances shall be calculated employing a
                  settlement price of $2.75 per Mcf. All plant and pipeline
                  imbalances shall be calculated in accordance with applicable
                  contracts, or if there are no applicable contracts, by the
                  mutual agreement of the Parties.

         (c)      In the event CMS or Terra are overproduced as to any well(s)
                  or unit(s) located on or appurtenant to the Subject Property
                  or the Terra Property, Purchaser acknowledges and agrees that
                  Purchaser's share of production from any such overproduced
                  well(s) or unit(s) acquired may at some point be curtailed by
                  an underproduced working interest owner(s), or that Purchaser
                  may be required to cash balance the amount of overproduction.
                  The Parties agree that CMS shall not be liable to the
                  Purchaser or any third party in the event curtailment or such
                  cash balancing occurs.

3.6      PURCHASE PRICE ALLOCATION

         Attached to this Agreement as Attachment H is a schedule setting forth
the agreed allocation of the Purchase Price among the portions of the Assets and
the Terra Assets.

                       ARTICLE IV - REPRESENTATIONS OF CMS

         CMS represents and warrants to Purchaser that, except as set forth in
the CMS Disclosure Schedule delivered by CMS to Purchaser on the date hereof and
initialed by the Parties, a copy of which is attached hereto as Attachment I,
each of the statements and representations contained in this Article IV are
true, correct and complete as of the date of this Agreement, and will be true,
correct and complete as of the Closing Date.

4.1      EXISTENCE

         CMS is incorporated under the business corporation statute of the State
of Michigan and is in good standing in the state.

4.2      AUTHORIZATION

         The execution, delivery and performance of this Agreement and the
transaction contemplated by it have been authorized by the requisite corporate
action on the part of CMS. This Agreement has been executed by a representative
of CMS empowered by CMS to execute this Agreement, and it has



                                       12
<PAGE>   18

been delivered on behalf of CMS. At Closing, all documents and instruments
required to be executed and delivered by CMS shall have been so executed and
delivered. This Agreement does, and the documents and instruments executed and
delivered shall, constitute legal, valid and binding obligations of CMS
enforceable in accordance with their terms, subject to effects of bankruptcy,
insolvency, reorganization, moratorium and similar laws in effect relating to
the rights and remedies of creditors, as well as to general principles of
equity.

4.3      BROKERS

         CMS has not incurred any liability, contingent or otherwise, for
broker's or finder's fees or commissions relating to the transaction
contemplated by this Agreement for which Purchaser shall have any responsibility
whatsoever.

4.4      NONCONTRAVENTION

          Neither the execution and the delivery of this Agreement, nor the
consummation of the transaction contemplated hereby, will (i) violate any
constitution, statute, regulation, rule, injunction, judgment, order, decree,
ruling, charge, or other restriction of any government, governmental agency, or
court to which CMS is subject or any provision of its charter or bylaws, or
(ii), except for the third party preferential rights to purchase, rights of
reconveyance, consents to sell or assign or confidentiality agreements, as
referenced in Article XX, conflict with, result in a breach of, constitute a
default under, result in the acceleration of, create in any party the right to
accelerate, terminate, modify, or cancel, any agreement, contract, lease,
license, instrument, or other arrangement to which CMS is a party or by which it
is bound or to which any of the Assets is subject.

4.5      TERRA SHARES

         CMS holds of record and owns beneficially all of the Terra Shares, free
and clear of any restrictions on transfer (other than restrictions under the
Securities Act and state securities laws), taxes, Security Interest, options,
warrants, purchase rights, contracts, commitments, equities, claims, and
demands. CMS is not a party to any option, warrant, purchase right, or other
contract or commitment that could require CMS to sell, transfer, or otherwise
dispose of any capital stock of Terra (other than this Agreement). CMS is not a
party to any voting trust, proxy, or other agreement or understanding with
respect to the voting of any Terra Shares.

4.6      LEGAL COMPLIANCE

         To the Knowledge of CMS, CMS has complied with all applicable laws
(including rules, regulations, codes, plans, injunctions, judgments, orders,
decrees, rulings and charges thereunder) of federal, state and local governments
(and all agencies thereof) relating to or affecting the Subject Property, except
where the failure to comply would not have a material adverse effect upon the
affected Asset.

4.7      EXCLUDED ASSETS

         None of the gas reserves that constitute the Assets or the Terra Assets
will be, as of the Closing Date, dedicated to the Natural Gas Purchase Agreement
(effective May 1, 1989) between Midland Cogeneration Venture Limited Partnership
and Northern Michigan Exploration Company and CMS Energy Corporation, as
referenced in Section 1.2.



                                       13
<PAGE>   19



4.8      ENVIRONMENTAL, HEALTH AND SAFETY MATTERS

         Except as set forth in Section 4.8 of the CMS Disclosure Schedule, CMS
is in compliance with all Environment, Health and Safety Requirements insofar as
the same pertain to the Assets, except where the failure to comply would not
have a material adverse effect upon the Assets, and except as set forth in
Section 4.8 of the Disclosure Schedule, neither CMS nor the Assets is the
subject of any order, ruling, proceeding, hearing or investigation, either
pending or overtly threatened relating to Environmental, Health and Safety
Requirements. Except as set forth in Section 4.8 of the CMS Disclosure Schedule,
CMS has not received any written notice, report or other information regarding
any actual or alleged material violation of any Environmental, Health and Safety
Requirements with respect to the Assets, and as of the Effective Date no
condition exists with respect to the Assets that could give rise to future
liability or obligations under the Environmental, Health and Safety
Requirements.

4.9      LITIGATION

         Except as set forth in Section 4.9 of the CMS Disclosure Schedule,
there is no outstanding injunction, judgment, order, decree, ruling or charge
which could have a material adverse effect on the Assets, nor, except as set
forth in Section 4.9 of the CMS Disclosure Schedule, CMS a party to any action,
suit, proceeding, hearing or investigation, pending or overtly threatened, which
involves the Assets, or CMS's ownership or operation of the Assets.

4.10     COMPLIANCE WITH CONTRACTS

         CMS has performed all of its obligations under the terms of all
contracts and agreements pertaining to the Assets except where the failure to
perform would not have a material adverse effect upon the Assets, and CMS has
not received written notice from any party of an alleged default by CMS under
the terms of any contract or agreement, or that any contract or agreement is not
valid and enforceable in accordance with its terms insofar, and only insofar, as
same relate to the Assets. Anything to the contrary contained herein,
notwithstanding, this Section 4.10 does not, and shall not under any
circumstances be deemed to include or apply to matters constituting a Title
Defect in accordance with Section 13.8, below, whether or not a Claim of Title
Defect has been timely and properly asserted with respect thereto.

4.11     TAX MATTERS

         (a)      To the Knowledge of CMS, except as set forth in Section
                  4.11(a) of the CMS Disclosure Schedule, CMS has paid, or will
                  pay in full all taxes and assessments with respect to the
                  Assets that are due prior to the Effective Date, including all
                  ad valorem, property, production, severance and Other Taxes;
                  to the Knowledge of CMS, except as set forth at Section
                  4.11(a) of the CMS Disclosure Schedule, all tax returns and
                  reports required to be filed prior to the Effective Date have
                  been or will be timely and accurately filed; and to the
                  Knowledge of CMS, except as set forth in Section 4.11(a) of
                  the CMS Disclosure Schedule, no tax deficiencies have been
                  assessed, nor is there any audit in progress or threatened
                  with respect to taxes due on the Assets.

         (b)      (i)      All applications for well determinations for each
                           Qualifying Well have been filed with the applicable
                           state and federal agencies under the Natural Gas
                           Policy Act of 1978, as amended (the "NGPA") and the
                           rules and regulations of the Federal Energy
                           Regulatory Commission (the "FERC") under NGPA (the
                           "NGPA Regulations") requesting a determination that
                           all of the gas produced from each Qualifying Well is
                           produced from "Devonian shale". Each such application
                           has been approved by the applicable state agency and
                           by the FERC and has been finally approved under and
                           in accordance with section 503 of the NGPA (as
                           evidenced by appropriate FERC certification). Such
                           applications comply



                                       14
<PAGE>   20

                           with the requirements of the NGPA and NGPA
                           Regulations. True and correct copies of such
                           certifications have been furnished to Buyer. No
                           further applications are required under the NGPA and
                           the NGPA Regulations to allow the legal sale of all
                           gas produced from the Qualifying Wells at a price
                           equal to the price for such gas currently being
                           received. No production from the Qualifying Wells
                           qualifies for incentive prices under section 107 of
                           the NGPA or the deregulation provisions of the NGPA
                           or Subtitle 13 of Title I of the NGPA.

                  (ii)    A)       Except as set forth at Section 4.11(b) of
                                   the CMS Disclosure Schedule, each Qualifying
                                   Well was drilled (within the meaning of
                                   section 29(f) of the Code) after December 31,
                                   1979 and prior to January 1, 1993, and was
                                   completed as a well capable of producing from
                                   the formation described in section 3.01(x)
                                   (iii) of the NGPA; and

                           B)      All gas (except carbon dioxide) produced from
                                   each Qualifying Well is a "qualified fuel"
                                   under section 29(c) of the Code.

                  (iii)    Except as set forth at Section 4.11(b) of the CMS
                           Disclosure Schedule, the Qualifying Wells are
                           perforated only in the Antrim Formation and the gas
                           produced from each Qualifying Well is not commingled
                           with any gas from that Qualifying Well that is not
                           produced from such formation.

                  (iv)     Prior to January 1, 1980, there was no production of
                           coal seam, Devonian shale, geopressured brine or
                           tight formation gas in marketable quantities from the
                           "property" (as used in section 29 of the Code) on
                           which any Qualifying Well is located.

                  (v)      No oil or gas produced from the Qualifying Wells
                           qualifies or has qualified for the enhanced oil
                           recovery credit or any other credit under section 43
                           of the Code and none has been claimed or taken on
                           such oil or gas.

                  (vi)     No credits referred to in section 29(b)(4) have been
                           claimed with respect to any Qualifying Wells.

                  (vii)    None of the special financing arrangements described
                           in subclauses (I), (II), or (III) of section 29(b)
                           (3)(A)(i) of the Code


                                       15
<PAGE>   21


                           have been provided in connection with any project
                           that includes any of the Qualifying Wells.

4.12     COMPLIANCE WITH PERMITS AND LICENSES

         To the Knowledge of CMS, CMS possesses all material federal, state and
local governmental and regulatory franchises, rights, privileges, permits,
grants, concessions, licenses, certificates, variances, authorizations and
approvals necessary to own and/or operate the Subject Property.

         To the Knowledge of CMS, except as listed at Section 4.12 of the CMS
Disclosure Schedule, all Permits which are to remain in effect after the
Closing, are in full force and effect and will continue in full force and effect
through the Closing Date. To the Knowledge of CMS, except as listed at Section
4.12 of the CMS Disclosure Schedule, CMS is not in default in any material
respect under the terms of any Permit which is to survive the Closing, nor to
the Knowledge of CMS, has it received notice of any material default thereunder
which has not, or will not be resolved as of the Closing Date.

4.13     TITLE

         Subject to Section 18.1, below, and except for the Permitted
Encumbrances, as defined in Section 13.7, below, CMS has Defensible Title, as
defined in Section 13.6, below, to the Assets free and clear of all material
Title Defects, as defined in Section 13.8, below.

4.14     CONSENTS, APPROVALS AND RIGHTS TO ACQUIRE

         Except for consents, required notices to, filings with or other actions
by governmental entities which are customarily obtained subsequent to Closing,
and except as set forth at Section 4.14 of the CMS Disclosure Schedule, to the
Knowledge of CMS, no consent, approval, notice to or filing with any government
or governmental agency, or any other party, is required in connection with the
execution, delivery and performance of this Agreement by CMS, or as a condition
to the validity or enforceability of this Agreement and the consummation of the
transaction contemplated by this Agreement. Subject to the provisions of Article
XX, below, CMS shall identify and properly notify all parties who hold any
preferential right or option to purchase the Assets, or any part thereof, or
whose consent is required to transfer the Assets or any portion thereof.

4.15     GAS CONTRACTS

         Except as set forth at Section 4.15 of the CMS Disclosure Schedule, to
the Knowledge of CMS production from or attributable to the Subject Property is
not dedicated to any gas sales contracts, other than those which are terminable
upon thirty (30) day written notice.

4.16     SECURITIES DISCLOSURE/REPRESENTATION

         CMS is acquiring the QRI Stock for its own account and not with a view
to or for offer or resale in connection with any distribution thereof within the
meaning of the Securities Act and the rules and regulations pertaining to the
Securities Act, or a distribution thereof in violation of the Security Act, or
any other applicable federal or state securities laws. CMS is not acting as an
undisclosed agent for any other party or parties. CMS is an Accredited Investor.

         CMS acknowledges that Purchaser has entered into this Agreement and
will consummate the transaction contemplated by this Agreement, in reliance on
CMS's representations and warranties under this Article IV.




                                       16
<PAGE>   22

                    ARTICLE V - REPRESENTATIONS OF PURCHASER

         Purchaser represents and warrants to CMS that each of the statements
and representations contained in this Article V are true, correct and complete
as of the date of this Agreement, and will be true, correct and complete as of
the Closing Date:

5.1      EXISTENCE

         Purchaser is incorporated under the business corporation statute of the
State of Delaware and is in good standing in the state, and is qualified to
carry on its business in the State of Michigan and is in good standing as a
foreign corporation under the business corporation statute of the State of
Michigan.

5.2      EXECUTION

         The execution, delivery and performance of this Agreement by Purchaser,
and the transaction contemplated by this Agreement, will not violate (i) any
provision of the certificate or articles of incorporation or bylaws of
Purchaser, (ii) any material agreement or instrument to which Purchaser is a
party or by which Purchaser is bound, (iii) any judgment, order, ruling, or
decree applicable to Purchaser as a party in interest, or (iv) any law, rule or
regulation applicable to Purchaser.

5.3      AUTHORIZATION

         The execution, delivery and performance of this Agreement and the
transaction contemplated by it have been authorized by requisite corporate
action on the part of Purchaser. This Agreement has been executed by an officer
or other representative of Purchaser empowered by Purchaser to execute this
Agreement, and it has been delivered by Purchaser. At the Closing, all documents
and instruments required to be executed and delivered by Purchaser shall have
been so executed and delivered. This Agreement does, and the documents and
instruments executed and delivered shall, constitute legal, valid and binding
obligations of Purchaser enforceable in accordance with their terms, subject to
the effects of bankruptcy, insolvency, reorganization, moratorium and similar
laws in effect relating to the rights and remedies of creditors, as well as to
general principles of equity. Purchaser need not give any notice to, make any
filing with, or obtain any authorization, consent or approval of any government
or governmental agency in order to consummate the transaction contemplated by
this Agreement.

5.4      BROKERS

         Purchaser has not incurred any liability, contingent or otherwise, for
broker's or finder's fees or commissions relating to the transaction
contemplated by this Agreement for which CMS shall have any responsibility
whatsoever.

5.5      NONCONTRAVENTION

         Neither the execution and the delivery of this Agreement, nor the
consummation of the transaction contemplated hereby, will (i) violate any
constitution, statute, regulation, rule, injunction, judgment, order, decree,
ruling, charge, or other restriction of any government, governmental agency, or
court to which Purchaser is subject or any provision of its charter or bylaws,
or (ii) conflict with, result in a breach of, constitute a default



                                       17
<PAGE>   23

under, result in the acceleration of, create in any party the right to
accelerate, terminate, modify, or cancel, or require any notice under any
agreement, contract, lease, license, instrument, or other arrangement to which
Purchaser is a party or by which it is bound or to which any of its assets is
subject.

5.6      INDEPENDENT EVALUATION AND TITLE REVIEW

         Purchaser will be afforded the opportunity, at its own cost and risk,
to inspect the Assets and the Terra Assets and to examine copies of data and
records in CMS's and Terra's possession affecting the Assets and the Terra
Assets. Purchaser will be given access to all title, division order files,
contract and lease records and data, and all production, engineering,
environmental and other technical data, insofar as the foregoing relates to the
Assets and the Terra Assets, (but not including data and records which CMS, in
its sole discretion considers to be privileged, proprietary or confidential to
it and which are not directly related to the condition, quality and quantity of
the Assets, or which CMS or Terra cannot legally provide Purchaser because of
third party restriction on CMS or Terra, or disclosure of which will violate any
agreement to which CMS or Terra is a party). PURCHASER ACKNOWLEDGES THAT EXCEPT
AS OTHERWISE SPECIFIALLY PROVIDED IN THIS AGREEMENT, CMS HAS MADE NO
REPRESENTATIONS OR WARRANTIES AS TO THE CONDITION OF THE ASSETS OR THE TERRA
ASSETS, THE ACCURACY OR COMPLETENESS OF ANY DATA AND RECORDS PROVIDED BY CMS OR
TERRA, OR AS TO CMS'S TITLE TO THE ASSETS OR TERRA'S TITLE TO THE TERRA ASSETS.
IN ENTERING INTO AND PERFORMING THIS AGREEMENT, EXCEPT FOR, AND TO THE EXTENT OF
THE REPRESENATIONS AND WARRANTIES EXPRESSLY SET FORTH IN ARTICLES IV AND VI,
PURCHASER HAS RELIED AND WILL RELY SOLELY UPON ITS INDEPENDENT INVESTIGATION OF,
AND JUDGMENT WITH RESPECT TO THE ASSETS AND THE TERRA ASSETS, THEIR CONDITION,
VALUE AND CMS'S AND TERRA'S TITLE THERETO. The rights of Purchaser under this
Section 5.6 are expressly subject to the provisions of Article XII and Article
XIII, and except as specifically set forth in Article XII and Article XIII there
shall be no contingency to Purchaser completing the transaction contemplated by
this Agreement, with respect to such review and evaluation of the Assets and the
Terra Assets.

5.7      SECURITIES DISCLOSURE/REPRESENTATION

         Purchaser is acquiring the Assets for its own account and not with a
view to or for offer or resale in connection with any distribution thereof
within the meaning of the Securities Act and the rules and regulations
pertaining to the Securities Act, or a distribution thereof in violation of the
Security Act, or any other applicable federal or state securities laws.
Purchaser is not acting as an undisclosed agent for any other party or parties.
Purchaser is an Accredited Investor. Purchaser is and has been actively involved
in the business of owning and operating producing oil and gas properties for a
period in excess of five (5) years prior to the Effective Date, is knowledgeable
about the oil and gas exploration and production business, and is not relying on
CMS with regard to any expectations Purchaser may have about any future income
it may receive from the Assets or the Terra Assets.

5.8      BONDS AND PERMITS

         Purchaser or its designated operator, other than Terra, shall, as of
the Closing Date have all bonds which are designated at Attachment J. Purchaser
shall furnish CMS proof that such bonds are in full force and effect with
respect to the Subject Property and the Terra Property. As to those portions of
the Subject Property and Terra

                                       18
<PAGE>   24



Property for which CMS is named operator on the State of Michigan well permit,
Purchaser agrees, if necessary to take an assignment of all such well permits in
its name or in the name of its designee, other than Terra.

5.9      SECTION 29 TAX CREDITS

         Purchaser acknowledges that CMS will take or claim the section 29 tax
credits for production from the Qualifying Wells attributable to the Interim
Period, and Purchaser agrees not to take or claim such tax credits.

         Purchaser acknowledges that CMS has entered into this Agreement, and
will consummate the transaction contemplated by this Agreement, in reliance on
Purchaser's representations and warranties under this Article V.

                  ARTICLE VI - REPRESENTATIONS CONCERNING TERRA

         CMS represents and warrants to Purchaser that except as set forth in
the Terra Disclosure Schedule delivered by CMS to Purchaser on the date hereof
and initialed by the Parties, a copy of which is attached hereto as Attachment
K, each of the statements and representations contained in this Article VI are
true, correct and complete as of the date of this Agreement and will be true,
correct and complete as of the Closing Date.

6.1      ORGANIZATION, QUALIFICATION AND CORPORATE POWER

         Each of Terra and its Subsidiaries, and to the Knowledge of CMS,
Terra's Affiliates, is a corporation or limited liability company duly
organized, validly existing, and in good standing under the laws of the
jurisdiction of its formation. Each of Terra and its Subsidiaries, and to the
Knowledge of CMS, Terra's Affiliates, is duly authorized to conduct business and
is in good standing under the laws of each jurisdiction where such qualification
is required, except where the lack of such qualification would not have a
material adverse effect on the financial condition of Terra, its Subsidiaries
and Affiliates, taken as a whole. Each of Terra and its Subsidiaries, and to the
Knowledge of CMS, Terra's Affiliates has full power and authority to carry on
the businesses in which it is presently engaged and to own and use the
properties owned and used by it. The Terra Disclosure Schedule, at Section 6.1
thereof, identifies all of the Subsidiaries and Affiliates of Terra, and also
lists the directors and officers of each of Terra and its Subsidiaries.

6.2      CAPITALIZATION

         The entire authorized capital stock of Terra consists of twenty million
(20,000,000) shares, of which twelve million sixty-five thousand four hundred
and twenty-two (12,065,422) Terra Shares are issued and outstanding. The issued
and outstanding Terra Shares have been duly authorized, are validly issued,
fully paid, and nonassessable, and are held of record by CMS. There are no
outstanding or authorized options, warrants, purchase rights, subscription
rights, conversion rights, exchange rights, or other contracts or commitments
that could require CMS or Terra to issue, sell, or otherwise cause to become
outstanding any of the capital stock of Terra. Except as listed on the Terra
Disclosure Schedule at Section 6.2 thereof, the Terra Shares are free of any
pledge, lien, security interest or other encumbrance, and as of the Closing
Date, the Terra Shares shall be free and clear of any pledge, lien, security
interest or other encumbrance so listed at Section 6.2 of the Terra Disclosure
Schedule. There are no outstanding or authorized stock appreciation, phantom
stock, profit participation, or similar rights with respect to Terra.



                                       19
<PAGE>   25

6.3      NONCONTRAVENTION

         To the Knowledge of CMS, neither the execution and the delivery of this
Agreement, nor the consummation of the transaction contemplated hereby, will (i)
violate any constitution, statute, regulation, rule, injunction, judgment,
order, decree, ruling, charge, or other restriction of any government,
governmental agency, or court to which any of Terra and its Subsidiaries is
subject, or any provision of the charter, bylaws or operating agreement of any
of Terra and its Subsidiaries or (ii) except as listed on the Terra Disclosure
Schedule at Section 6.3 thereof, conflict with, result in a breach of,
constitute a default under, result in the acceleration of, create in any party
the right to accelerate, terminate, modify, or cancel any agreement, contract,
lease, license, instrument, or other arrangement to which any of Terra and its
Subsidiaries is a party or by which it is bound or to which any of the Terra
Assets is subject (or result in the imposition of any Security Interest upon any
of the Terra Assets), except where the violation, conflict, breach, default,
acceleration, termination, modification, cancellation, failure to give notice,
or Security Interest would not have a material adverse effect on the financial
condition of Terra and its Subsidiaries taken as a whole or on the ability of
the Parties to consummate the transaction contemplated by this Agreement. To the
Knowledge of CMS, except as listed on the Terra Disclosure Schedule at Section
6.3 thereof, none of Terra and its Subsidiaries needs to give any notice to,
make any filing with, or obtain any authorization, consent, or approval of any
government or governmental agency in order for the Parties to consummate the
transaction contemplated by this Agreement, except where the failure to give
notice, to file, or to obtain any authorization, consent, or approval would not
have a material adverse effect on the financial condition of Terra and its
Subsidiaries taken as a whole or on the ability of CMS to consummate the
transaction contemplated by this Agreement.

6.4      SUBSIDIARIES AND AFFILIATES

         The Terra Disclosure Schedule sets forth at Section 6.4 thereof for
each Subsidiary (i) its name, any assumed name under which it conducts business
and jurisdiction of incorporation, (ii) the number of shares of authorized
capital stock of each class of its capital stock, if any, (iii) the number of
issued and outstanding shares of each class of its capital stock, the names of
the holders thereof, and the number of shares held by each such holder, if any,
and (iv) the number of shares of its capital stock held in treasury, if any. All
of the issued and outstanding shares of capital stock of each Subsidiary of
Terra, have been duly authorized and are validly issued, fully paid, and
nonassessable. Terra holds of record and owns beneficially all of the
outstanding shares of each corporate Subsidiary of Terra.

6.5      FINANCIAL STATEMENTS

         Attached hereto at Attachment L are the following financial statements
(collectively the "Financial Statements"): (i) unaudited balance sheets and
statements of income as of and for the fiscal year ended December 31, 1997, for
Terra and its Subsidiaries consolidated; (ii) unaudited balance sheets and
statements of income as of and for the fiscal year ended December 31, 1998 for
Terra and each of its Subsidiaries; (iii) unaudited balance sheets and
statements of income, (the "Most Recent Financial Statements") as of and for the
twelve (12) months ended December 31, 1999 (the "Most Recent Fiscal Month End")
for Terra and each of its Subsidiaries; and (iv) the Consolidated Terra Energy
Pro Forma Balance Sheet dated December 31, 1999.



                                       20
<PAGE>   26

The Terra consolidated Financial Statements, Terra and each of its Subsidiaries
Financial Statements have been extracted from the CMS audited financial
statements which have been prepared in accordance with GAAP applied on a
consistent basis throughout the periods covered thereby, and accurately,
completely and fairly represent the financial condition of Terra as of December
31, 1999, and Terra has no other liabilities or obligations, except as set forth
at Section 6.5 of the Terra Disclosure Schedule. However, the Most Recent
Financial Statements are subject to normal year-end adjustments.

6.6      EVENTS SUBSEQUENT TO MOST RECENT FISCAL MONTH END

         Since the Most Recent Fiscal Month End, there has not been any material
adverse change in the financial condition of Terra and its Subsidiaries taken as
a whole. Without limiting the generality of the foregoing, since the Most Recent
Fiscal Month End none of Terra and its Subsidiaries has engaged in any practice,
taken any action, or entered into any transaction outside the Ordinary Course of
Business which may have a material adverse effect on the financial condition of
Terra and its Subsidiaries, taken as a whole.

6.7      LEGAL COMPLIANCE

         To the Knowledge of CMS, except as listed on the Terra Disclosure
Schedule at Section 6.7 thereof, each of Terra and its Subsidiaries has complied
with all applicable laws (including rules, regulations, codes, plans,
injunctions, judgments, orders, decrees, rulings, and charges thereunder) of
federal, state and local governments (and all agencies thereof), except where
the failure to comply would not have a material adverse effect upon the
financial condition of Terra and its Subsidiaries taken as a whole, or on the
ability of CMS to consummate the transaction contemplated by this Agreement.

6.8      TAX MATTERS

         (a)      Except as set forth on the Terra Disclosure Schedule at
                  Section 6.8(a) thereof, each of Terra and its Subsidiaries has
                  filed on or before the date hereof (or will timely file) all
                  Tax Returns that are required to be filed on or before the
                  Closing Date, and has paid all Taxes shown thereon as owing,
                  except where the failure to file Tax Returns or to pay Taxes
                  would not have a material adverse effect on the financial
                  condition of Terra and its Subsidiaries taken as a whole.

         (b)      The Terra Disclosure Schedule at Section 6.8(b) thereof, (i)
                  lists all Tax Returns filed with respect to any of Terra and
                  its Subsidiaries for taxable periods commencing on or after
                  August 31, 1995, (ii) indicates those Tax Returns that have
                  been audited, and (iii) indicates those Tax Returns that
                  currently are the subject of audit. CMS has delivered to
                  Purchaser correct and complete copies of all Tax Returns,
                  including Federal Income Tax Returns, examination reports, and
                  statements of deficiencies assessed against or agreed to by
                  any of Terra and its Subsidiaries since August 31, 1995.

         (c)      All such Tax Returns for taxable years or periods ending on or
                  before December 31, 1998 are (or will be) complete and
                  accurate in all material respects and disclose all Taxes
                  required to be paid by Terra and its Subsidiaries for the
                  periods covered




                                       21
<PAGE>   27

                  thereby, except for Taxes for which adequate reserves have
                  been established by Terra or its Subsidiaries and such
                  reserves are reflected in the computation of Terra's
                  consolidated net working capital and all Taxes shown to be due
                  on such Tax Returns have been timely paid or are reflected in
                  the computation of Terra's consolidated net working capital,
                  and further except for any adjustments which may be made to
                  the Tax Return for the period ending December 31, 1998
                  pursuant to an Internal Revenue Service audit.

         (d)      Except as set forth on the Terra Disclosure Schedule at
                  Section 6.8(d) thereof, none of Terra or its Subsidiaries have
                  waived or been requested to waive any statute of limitations
                  in respect of any Taxes.

         (e)      Except as set forth on the Terra Disclosure Schedule at
                  Section 6.8(e) thereof, the Tax Returns for taxable years or
                  periods ending on or before December 31, 1998 have been
                  examined by the Internal Revenue Service, or the period for
                  assessment of Taxes in respect of which such Tax Returns were
                  required to be filed has expired.

         (f)      Except as set forth on the Terra Disclosure Schedule at
                  Section 6.8(f) thereof, there is no action, suit,
                  investigation, audit, claim or assessment pending or, to the
                  Knowledge of CMS, proposed or threatened with respect to Taxes
                  of Terra or its Subsidiaries for taxable years or periods
                  ending on or before December 31, 1998 and, to the Knowledge of
                  CMS, no basis exists therefor for which adequate reserves have
                  not been established and such reserves are reflected in the
                  computation of Terra's consolidated net working capital.

         (g)      Except as set forth on the Terra Disclosure Schedule at
                  Section 6.8(g) thereof, all deficiencies asserted or
                  assessments made as a result of any examination of the Tax
                  Returns for taxable years or periods ending on or before
                  December 31, 1998 have been paid in full or are reflected in
                  the computation of Terra's consolidated net working capital.

         (h)      Except as set forth on the Terra Disclosure Schedule at
                  Section 6.8(h) thereof, there are no Tax indemnity agreements
                  to which Terra or its Subsidiaries are a party or are bound.

         (i)      There are no liens for Taxes upon the Terra Assets, except
                  liens relating to current Taxes not yet due or which are
                  reflected in the computation of Terra's consolidated net
                  working capital.

         (j)      All Taxes which Terra or its Subsidiaries are required by law
                  to withhold or to collect for payment have been duly withheld
                  and collected, and have been paid or accrued.

         (k)      To the Knowledge of CMS, any accruals for deferred Taxes are
                  adequate to cover any deferred tax liability of Terra and its
                  Subsidiaries determined in accordance with GAAP through the
                  date thereof.

         (l)      There are no Tax rulings, requests for private letter rulings
                  or requests for technical advice, in each case initiated by
                  Terra or its Subsidiaries, or requests for a change in method
                  of



                                       22
<PAGE>   28

                  accounting or closing agreements relating to Terra or its
                  Subsidiaries for Taxes for any period after December 31, 1998.

         (m)      None of Terra or its Subsidiaries has filed a consent under
                  section 341(f) of the Code or any comparable provision of
                  state statutes.

         (n)      Since January 1, 1999, none of Terra or its Subsidiaries have
                  taken any action not in accordance with past practice that
                  would have the effect of deferring any Tax liability for Terra
                  or any Subsidiary from any taxable period ending on or before
                  December 31, 1998 to any taxable period ending after December
                  31, 1998.

         (o)      Except as set forth on the Terra Disclosure Schedule at
                  Section 6.8(o) thereof, no income or gain of Terra or its
                  Subsidiaries has been deferred pursuant to Treasury
                  Regulations ss.ss. 1.1502-13 or -14, or Temporary Treasury
                  Regulation ss.ss. 1.1502-13T or -14T.

         (p)      None of the Terra Assets is required to be treated as owned by
                  another Person pursuant to section 168(f)(8) of the Code (as
                  in effect prior to its amendment by the Tax Equity and Fiscal
                  Responsibility Act of 1982) or is "tax exempt use property"
                  within the meaning of section 168(h) of the Code or is subject
                  to a so-called TRAC lease under section 7701(h) of the Code or
                  any predecessor provision.

         (q)      Terra and its Subsidiaries are the owners for Income Tax
                  purposes of all property which it has leased to any Person.

         (r)      Neither Terra nor its Subsidiaries have participated in or
                  cooperated with an international boycott, within the meaning
                  of section 999 of the Code, and all filing requirements
                  imposed by section 999 of the Code with respect to Terra and
                  its Subsidiaries have been and will be complied with.

         (s)      Neither Terra nor its Subsidiaries have disposed of property
                  in a transaction being accounted for under the installment
                  method pursuant to section 453 or 453A of the Code.

         (t)      Neither Terra nor its Subsidiaries has any corporate
                  acquisition indebtedness, as described in section 279(b) of
                  the Code.

         (u)      Except as set forth on the Terra Disclosure Schedule at
                  Section 6.8(u) thereof, no Taxes with respect to any period
                  ending on or before December 31, 1998 were paid by Terra or
                  its Subsidiaries (or charged to Terra or its Subsidiaries
                  through any intercompany account or payment) after December
                  31, 1998.

         (v)      Except as set forth on the Terra Disclosure Schedule at
                  Section 6.8(v) thereof, no portion of the Terra Assets (i) has
                  been contributed to and is currently owned by a tax
                  partnership; (ii) is subject to any form of agreement (whether
                  formal or informal, written or oral) deemed by any state or
                  federal Tax statute, rule or regulation to be or to have
                  created a tax partnership; or (iii) otherwise constitutes
                  "partnership property" (as that term is used throughout
                  Subchapter K of Chapter 1 of Subtitle A of the Code) of a tax
                  partnership.


                                       23
<PAGE>   29


         (w)      (i)      All applications for well determinations for each
                           Qualifying Well have been filed with the applicable
                           state and federal agencies under the Natural Gas
                           Policy Act of 1978, as amended (the "NGPA") and the
                           rules and regulations of the Federal Energy
                           Regulatory Commission (the "FERC") under the NGPA
                           (the "NGPA Regulations") requesting a determination
                           that all of the gas produced from each Qualifying
                           Well is produced from "Devonian shale". Each such
                           application has been approved by the applicable state
                           agency and by the FERC and has been finally approved
                           under and in accordance with section 503 of the NGPA
                           (as evidenced by appropriate FERC certification).
                           Such applications comply with the requirements of the
                           NGPA and the NGPA Regulations. True and correct
                           copies of such certifications have been furnished to
                           Buyer. No further applications are required under the
                           NGPA and the NGPA Regulations to allow the legal sale
                           of all gas produced from the Qualifying Wells at a
                           price equal to the price for such gas currently being
                           received. No production from the Qualifying Wells
                           qualifies for incentive prices under section 107 of
                           the NGPA or the deregulation provisions of the NGPA
                           or Subtitle 13 of Title I of the NGPA.

                  (ii)     A)      Except as set forth at Section 6.8(w) of the
                                   Terra Disclosure Schedule, each Qualifying
                                   Well was drilled (within the meaning of
                                   section 29(f) of the Code) after December 31,
                                   1979 and prior to January 1, 1993, and was
                                   completed as a well capable of producing from
                                   the formation described in section
                                   3.01(x)(iii) of the NGPA; and

                           B)      All gas (except carbon dioxide) produced from
                                   each Qualifying Well is a "qualified fuel"
                                   under section 29(c) of the Code.

                  (iii)    Except as set forth at Section 6.8(w) of the Terra
                           Disclosure Schedule, the Qualifying Wells are
                           perforated only in the Antrim formation and the gas
                           produced from each Qualifying Well is not commingled
                           with any gas from that Qualifying Well that is not
                           produced from such formation.

                  (iv)     Prior to January 1, 1980, there was no production of
                           coal seam, Devonian shale, geopressured brine or
                           tight formation gas in marketable quantities from the
                           "property" (as used in section 29 of the Code) on
                           which any Qualifying Well is located.

                  (v)      No oil or gas produced from the Qualifying Wells
                           qualifies or has qualified for the enhanced oil
                           recovery credit or any other credit under section 43
                           of the Code and none has been claimed or taken on
                           such oil or gas.

                  (vi)     No credits referred to in section 29(b)(4) have been
                           claimed with respect to any Qualifying Wells.

                  (vii)    None of the special financing arrangements described
                           in subclauses (I), (II), or (III) of section
                           29(b)(3)(A)(i) of the Code have been provided in
                           connection with any project that includes any of the
                           Qualifying Wells.

6.9      POWERS OF ATTORNEY

         To the Knowledge of CMS, there are no outstanding powers of attorney
executed on behalf of any of Terra and its Subsidiaries.

6.10     LITIGATION

         Except as set forth in Section 6.10 of the Terra Disclosure Schedule
there is no outstanding injunction, judgment, order, decree, ruling or charge
which could have a material adverse effect on the Terra Assets, nor, except as
set forth in Section 6.10 of the Terra Disclosure Schedule is CMS or Terra a
party to any action, suit, proceeding, hearing or investigation, pending or
overtly threatened which involves the Terra Assets, or Terra's ownership or
operation of the Terra Assets.



                                       24
<PAGE>   30

6.11     EMPLOYEES AND EMPLOYEE BENEFITS

         (a)      As of the Effective Date, Terra has no employees or any
                  continuing obligations to any former employee(s) of Terra.

         (b)      Neither Terra nor its Subsidiaries maintains or contributes to
                  any Employee Benefit Plan, Employee Pension Benefit Plan,
                  Employee Welfare Benefit Plan or Multiemployer Plan.

         (c)      There are no claims or actions pending against Terra or its
                  Subsidiaries asserted by any Person or former employee, or any
                  governmental agency or body with respect to any employee
                  matter, and to the Knowledge of CMS there are no claims or
                  actions relating to any employment matter threatened against
                  Terra or its Subsidiaries.

6.12     ENVIRONMENTAL, HEALTH AND SAFETY MATTERS

         Except as set forth in Section 6.12 of the Terra Disclosure Schedule,
Terra is in compliance with all Environmental, Health and Safety Requirements
insofar as the same pertain to the Terra Assets, except where the failure to
comply would not have a material adverse effect upon the Terra Assets; and
except as set forth in Section 6.12 of the Terra Disclosure Schedule, neither
Terra nor the Terra Assets is the subject of any order, ruling, proceeding,
hearing or investigation, either pending or overtly threatened relating to
Environmental, Health and Safety Requirements. Except as set forth in Section
6.12 of the Terra Disclosure Schedule, neither CMS nor Terra has received any
written notice, report or other information regarding any actual or alleged
material violation of any Environmental, Health and Safety Requirements with
respect to the Terra Assets, and as of the Effective Date no condition exists
with respect to the Terra Assets that could give rise to future liability or
obligations under the Environmental, Health and Safety Requirements.

6.13     NO GUARANTIES; EXTENSION OF CREDIT

         Except as set forth in the Terra Disclosure Schedule at Section 6.13
thereof, and further except for customary indemnification and guaranty
provisions contained in any operating agreement or other commonly employed oil
and gas agreements, and further except for extensions of credit made in the
Ordinary Course of Business, no material obligations or liabilities of Terra or
its Subsidiaries are guaranteed by or subject to a similar contingent obligation
of any other Person, nor has Terra or its Subsidiaries guaranteed or become
subject to a similar contingent obligation in respect of the obligations or
liabilities of, or extended credit to any other Person. With respect to the CMS
Oil and Gas Company Credit Agreement referenced at Section 6.13 of the Terra
Disclosure Schedule, CMS represents that it will obtain a release of Terra as
guarantor thereunder at or prior to the Closing Date.

6.14     PERMITS

         To the Knowledge of CMS, each of Terra and its Subsidiaries and
Affiliates possesses all material federal, state and local governmental and
regulatory franchises, rights, privileges, permits, grants, concessions,
licenses, certificates, variances, authorizations, approvals, and other material
authorizations (including any amendments to any thereof) necessary


                                       25
<PAGE>   31


to own or lease and operate the Terra Assets and to conduct its business as now
conducted (collectively, the "Permits").

         To the Knowledge of CMS, except as listed on the Terra Disclosure
Schedule at Section 6.14 thereof, all Permits are in full force and effect and
will continue in full force and effect through the Closing Date. To the
Knowledge of CMS, except as listed on the Terra Disclosure Schedule at Section
6.14 thereof, neither Terra nor its Subsidiaries and Affiliates is in default in
any material respect under the terms of any Permit nor to the Knowledge of CMS
has Terra or its Subsidiaries and Affiliates received notice of any material
default thereunder which has not, or will not be resolved as of the Closing
Date.

6.15     COMPLIANCE WITH CONTRACTS

         Terra has performed all of its obligations under the terms of all
contracts and agreements pertaining to the Terra Assets, except where the
failure to perform would not have a material adverse effect upon the Terra
Assets, and neither CMS nor Terra has received written notice from any party of
an alleged default by Terra under the terms of any contract or agreement, or
that any contract or agreement is not valid and enforceable in accordance with
its terms insofar, and only insofar, as same relate to the Terra Assets.
Anything to the contrary contained herein, notwithstanding, this Section 6.15
does not, and shall not under any circumstances be deemed to include or apply to
matters constituting Title Defects in accordance with Section 13.8, below,
whether or not a Claim of Title Defect has been timely and properly asserted
with respect thereto.

6.16     TITLE

         Subject to Section 18.1, below, and except for the Permitted
Encumbrances, as defined in Section 13.7, below, Terra has Defensible Title, as
defined in Section 13.6, below, to the Terra Assets free and clear of all
material Title Defects, as defined in Section 13.8, below.

6.17     CONSENTS, APPROVALS AND RIGHTS TO ACQUIRE

         Subject to the provisions of Article XX, below, CMS shall identify and
properly notify all parties who hold any preferential right or option to
purchase the Terra Assets, or any part thereof, or whose consent is required to
consummate the transaction contemplated by this Agreement.

6.18     GAS CONTRACTS

         Except as set forth at Section 6.18 of the Terra Disclosure Schedule,
to the Knowledge of CMS, production from or attributable to the Terra Property
is not dedicated to any gas sales contracts, other than those which are
terminable upon thirty (30) day written notice.

6.19     MATERIAL CONTRACTS

         Except as contemplated by this Agreement, and except as set forth in a
schedule of material contracts to be furnished by CMS to Purchaser on or before
March 27, 2000, or in any Attachment to this Agreement, and except for those
agreements, instruments or documents included in subpart (b) below, to the
extent contained in the files and records, including without limitation computer
files and records, located either at Terra's offices in Traverse City, Michigan
or CMS's offices in Houston, Texas, and made fully available to Purchaser,
neither Terra nor any of its Subsidiaries is a party to or is bound by any
material written or oral contract, agreement, commitment or instrument or
amendment to any of the foregoing (excluding any of the foregoing which has been
fully performed by all parties) of the type or in the nature of those enumerated
below:

         (a)      for the purchase, sale or lease (except if the scheduled lease
                  payments are less than $10,000 per year) of real property;

         (b)      relating to oil and gas leases, licenses, permits and similar
                  arrangements, operating agreements, farm-out and farm-in
                  agreements, service contracts and similar agreements, option
                  agreements,


                                       26
<PAGE>   32


                  pooling and unitization agreements, production marketing
                  agreements, gas balancing agreements, gas purchase and sales
                  contracts, production sales contracts, processing agreements,
                  permits, licenses and orders, easements, rights of way,
                  pipeline agreements, exploration agreements, participation
                  agreements, oil sales contracts, and all agreements or
                  amendments relating to the same, or assignments of rights or
                  obligations under any such agreements, all relating to the
                  exploration for or the development, production, treating,
                  processing, transportation or marketing of hydrocarbons;

         (c)      which provides for, or relates to, the guarantee by Terra or
                  any of its Subsidiaries of any obligation of any customers,
                  suppliers, officers, directors, employees or affiliates of
                  Terra or such Subsidiaries;

         (d)      which provides for, or relates to, the incurrence by Terra or
                  any of its Subsidiaries of debt for borrowed money in excess
                  of $10,000;

         (e)      which provides for, or relates to, any non-competition or
                  confidentiality arrangement with any person, including any
                  current or former director, officer or employee of Terra or
                  any of its Subsidiaries;

         (f)      for capital expenditures in excess of $25,000 for any single
                  project or related series of projects;

         (g)      any partnership, joint venture or other similar arrangements
                  or agreements involving a sharing of profits or losses;

         (h)      which (other than contracts, agreements, commitments and
                  instruments of the nature described in clauses (a) through (g)
                  above) involve payments or receipts by Terra or any of its
                  Subsidiaries of more than $10,000; and

         (i)      for any purpose which is material to the business of Terra and
                  its Subsidiaries taken as a whole.

6.20     DISCLAIMER OF ALL OTHER REPRESENTATIONS AND WARRANTIES

         Except as expressly set forth in Article IV and this Article VI, CMS
makes no representation or warranty, express or implied, at law or in equity, in
respect of the Assets, the Terra Assets, or the assets of any of Terra's
Subsidiaries or Affiliates, including, without limitation, with respect to
merchantability or fitness for any particular purpose of the Assets, the Terra
Assets or the assets of any of Terra's Subsidiaries or Affiliates, and any such
other representations or warranties are hereby expressly disclaimed.

                   ARTICLE VII - OPERATIONS AND CASUALTY LOSS

7.1      REVENUES AND EXPENSES

         During the Interim Period, CMS shall continue to receive proceeds from
the sale of hydrocarbons produced from or allocated to the Subject Property and
the Terra Property and all other proceeds attributable to the Assets and the
Terra Assets. CMS and Terra will continue to pay expenses attributable to the
Assets and the Terra Assets in the same manner as before the Effective Date. At
Closing, the Purchase Price shall be adjusted for such proceeds and expenses in
the manner set forth in Section 3.3, above.

7.2      OPERATIONS AND LOSS OF ASSETS AND TERRA ASSETS

         (a)      Purchaser acknowledges that portions of the Subject Property
                  and the Terra Property may be producing oil and/or gas
                  properties, or

                                       27
<PAGE>   33


                  may be pooled with producing oil and/or gas properties.
                  Purchaser agrees that until Closing, the Assets and the Terra
                  Assets may continue to be operated and hydrocarbons will
                  continue to be produced from the Subject Property and the
                  Terra Property or properties pooled therewith. CMS and Terra,
                  as to the portions of the Subject Property and the Terra
                  Property which CMS or Terra now operates, shall continue to
                  operate the same in a good and workmanlike manner until the
                  Transfer Date, when such operations, to the extent permitted
                  by applicable contracts and agreements, shall be turned over
                  to and become the responsibility of Purchaser; unless an
                  applicable unit, pooling, communitization or operating
                  agreement otherwise requires, in which case (unless Purchaser
                  and CMS otherwise agree) CMS or Terra shall continue the
                  physical operation of such portions of the Subject Property
                  and the Terra Property, if permitted by, and pursuant to and
                  under the terms of such applicable contract(s) and
                  agreement(s), until such time after Closing as such applicable
                  contract(s) and agreement(s) may require; provided, however,
                  if the transaction contemplated by this Agreement proceeds to
                  Closing, then Purchaser shall assume all risk of, and CMS
                  shall have no liability to Purchaser for, losses or damages
                  sustained, or liabilities incurred, except as may result
                  directly from CMS's gross negligence or willful misconduct in
                  conducting the operation of the Subject Property and the Terra
                  Property (or portions thereof) after the Effective Date. Any
                  such loss, damage or liability which Purchaser seeks to impose
                  on CMS, shall be limited to the rights and remedies provided a
                  non-operator under the applicable contract(s) or agreement(s).
                  Purchaser shall have no recourse against CMS if the applicable
                  contract(s) or agreement(s) delay or prevent Purchaser from
                  assuming operation of the operated portions of the Subject
                  Property and the Terra Property. In no event shall CMS be
                  required to operate the operated portions of the Subject
                  Property or the Terra Property for a period longer than two
                  (2) months after the Closing Date. In the event that Purchaser
                  is unable, for any reason, to assume operatorship of any of
                  the Subject Properties or the Terra Properties which CMS
                  continues to operate as of that date, then CMS will appoint
                  Purchaser as its contract operator, and Purchaser shall, and
                  does hereby agree to assume all operations on the operated
                  portions of the Subject Property and the Terra Property.
                  Purchaser shall thereafter assume and be responsible for, and
                  shall defend, indemnify, and hold CMS, its parents, affiliates
                  and subsidiary corporations, as well as CMS's and their
                  officers, directors, shareholders, employees, and agents,
                  harmless from, against and in respect of any and all Claims
                  based upon, arising out of or related to operation of the
                  operated portions of the Subject Property and the Terra
                  Property, including but not limited to accounting,
                  disbursement of revenues and other general administrative
                  matters relating thereto. Purchaser shall be entitled to all
                  applicable fees and charges relating to such operations which
                  are attributable to periods from and after the date on which
                  Purchaser assumes operatorship of each of the wells and units
                  comprising the operated portions of the Subject Property and
                  the Terra Property. Operation of any portion of the Subject
                  Property or the Terra Property from and after the Effective
                  Date by CMS shall be for and on behalf of Purchaser, and CMS
                  shall make appropriate charges to Purchaser, including
                  overhead charges, for the share of all such charges
                  attributable to the Subject Property and the Terra Property,
                  and to all other working interest owners, which charges shall
                  be


                                       28
<PAGE>   34

                  retained by CMS and not paid or credited to Purchaser
                  regardless of when invoiced and received. Except as otherwise
                  provided in Sections 8.4 and 15.2(k),below, all such charges
                  shall be made in accordance with the applicable operating
                  agreement for each such property, or the applicable contract
                  which otherwise controls. If there are no presently effective
                  operating agreements or contracts, then such charges will be
                  in accordance with the applicable COPAS rate for the area and
                  type of well to which the charges apply, as determined by CMS.
                  Any such charges and expenses due from Purchaser or which are
                  due from third parties and are received by Purchaser,
                  regardless of when invoiced and received, may be recovered by
                  CMS as part of the Closing or Post-Closing Adjustments
                  (pursuant to Sections 15.2(e) and 16.2, below), as
                  appropriate. Purchaser, its heirs, successors, and affiliates
                  shall assume the risk of, and shall defend, indemnify, and
                  hold CMS, its parents, affiliates, and subsidiary
                  corporations, as well as CMS's and their officers, directors,
                  shareholders, employees and agents, harmless from, against and
                  in respect of any and all Claims, based upon, arising out of,
                  or attributable to personal injury, loss of life or damage to
                  property suffered or sustained as the result of any action or
                  activity related to operation of the Subject Property and the
                  Terra Property on or after the Effective Date, except to the
                  extent that such personal injury, loss of life or damage to
                  property was exclusively and directly caused by CMS's gross
                  negligence or willful misconduct.

         (b)      Purchaser acknowledges and agrees that CMS cannot and does not
                  covenant or warrant that Purchaser shall become successor
                  operator of all or any part of the portion of the Subject
                  Property which CMS currently operates, nor that Terra shall be
                  allowed to continue as operator of all or any part of the
                  portions of the Terra Property which it operates, since the
                  Subject Property and the Terra Property may be subject to
                  unit, pooling, communitization or operating agreements or
                  other agreements which control the appointment of a successor
                  operator. Purchaser will take the necessary action to attempt
                  to succeed CMS, or to allow Terra to continue as operator as
                  to all properties operated by CMS or Terra as of the Effective
                  Date. CMS agrees, however, that as to the portion of the
                  Subject Property which it operates, where it will assist to
                  facilitate the appointment of a successor operator, CMS will,
                  upon Purchaser's written request, resign as operator at
                  Closing. Purchaser will act expeditiously to take all
                  reasonable measures, including, but not limited to, taking
                  action prior to Closing if the Parties mutually agree that
                  such action is appropriate, to have Purchaser appointed
                  successor operator of those portions of the Subject Property
                  which CMS operates, or, if the necessary votes under the
                  applicable agreement(s) cannot be obtained to appoint
                  Purchaser as successor operator, to have another working
                  interest owner of such properties appointed successor
                  operator, per the terms of any applicable operating or other
                  agreement(s).

         (c)      If the transaction contemplated by this Agreement proceeds to
                  closing, then the risk of casualty loss of the Assets and the
                  Terra Assets shall pass to Purchaser as of the Effective Date.
                  CMS shall maintain its current insurance on the Assets and the
                  Terra Assets through the Transfer Date, and the Purchase Price
                  shall be adjusted upward to reflect a prorata share of the
                  paid premiums of all such insurance attributable to periods
                  after the


                                       29
<PAGE>   35

                  Effective Date. Attached hereto as Attachment M is a schedule
                  of the insurance coverages which CMS presently maintains with
                  respect to the Assets and the Terra Assets. CMS shall be
                  entitled to receive any and all insurance proceeds relating to
                  the Assets and the Terra Assets attributable to events which
                  occurred prior to the Effective Date, and if the transaction
                  contemplated by this Agreement proceeds to Closing, then
                  Purchaser shall be entitled to receive any and all insurance
                  proceeds attributable to events which occur on or after the
                  Effective Date. In addition, Purchaser shall assume all risk
                  of any change in condition of the Assets and the Terra Assets
                  which occurs during the Interim Period, except to the extent
                  any change in condition is exclusively and directly caused by
                  the gross negligence or willful misconduct of CMS or Terra.


                  ARTICLE VIII - PRE-CLOSING OBLIGATIONS OF CMS

8.1      ENCUMBRANCES

         During the Interim Period, except as otherwise approved by Purchaser
and except for the operation of the Subject Property and the Terra Property and
the production and sale of hydrocarbons from or allocable to the Subject
Property and the Terra Property in the Ordinary Course of Business as otherwise
provided in this Agreement, CMS and Terra shall not transfer, sell, hypothecate,
encumber or otherwise dispose of any of the Assets or the Terra Assets (other
than as required in connection with the exercise by third parties of
preferential rights to purchase or rights of reconveyance or similar rights,
applicable to any portion of the Assets or the Terra Assets as provided in
Article XX).

8.2      APPROVALS/CONSENTS

         During the Interim Period, CMS covenants and agrees that it will use
reasonable efforts to identify and obtain all permissions, approvals and
consents by any governmental authorities or agencies as may be required to
consummate the transaction contemplated hereunder (excluding governmental
permissions, approvals and consents which are customarily obtained after the
assignment of an oil and gas lease or interest). Consistent with Section 9.1,
below, Purchaser shall assist CMS in timely identifying and obtaining all such
items. The Parties shall cooperate to identify all such permissions, approvals
and consents in a timely manner so as to permit the Closing to occur on or
before the Closing Date. Except for an appropriate adjustment to the Purchase
Price, consistent with Attachment H, Purchaser shall have no recourse against
CMS with regard to any loss occasioned by the failure to properly identify or
timely notify any such permission, approval or consent. CMS shall promptly
notify Purchaser of any written claim received by CMS from any third party
relating to such permissions, approvals or consents.

8.3      NOTICES AND CONSENTS

         CMS shall, and will cause each of Terra and its Subsidiaries to give
any notices to, make any filings with, and use commercially reasonable efforts
to obtain any authorizations, consents, and approvals of governments and
governmental agencies in connection with the matters referred to in Section 4.4
and Section 6.3, above, if any.




                                       30
<PAGE>   36

8.4      OPERATION OF BUSINESS

         CMS will not cause or permit any of Terra and its Subsidiaries to
engage in any practice, take any action, or enter into any transaction outside
the Ordinary Course of Business, which may have a material adverse effect on the
financial condition of Terra and its Subsidiaries taken as a whole. Without
limiting the generality of the foregoing, CMS will not cause or permit any of
Terra and its Subsidiaries to engage in any practice, take any action, or enter
into any transaction outside the Ordinary Course of Business the primary purpose
or effect of which will be to generate or preserve Cash. From and after the date
of this Agreement, neither CMS nor Terra shall incur or consent to any
extraordinary or unusual expense with respect to the Assets or the Terra Assets
in excess of $50,000.00 without first obtaining Purchaser's written consent.

8.5      FULL ACCESS

         CMS will permit, and CMS will cause each of Terra and its Subsidiaries
to permit representatives of the Purchaser to have full access at all reasonable
times, and in a manner so as not to interfere with the normal business
operations of CMS, Terra and its Subsidiaries, to all premises, properties,
personnel, books, financial and other records (including without limitation tax
records and to the extent prepared, net operating statements for the years 1997,
1998 and 1999), contracts, and documents of or pertaining to each of the Assets
and the Terra Assets. CMS shall also permit representatives of the Purchaser to
have full access at all reasonable times, and in a manner so as not to interfere
with the normal operations of the Assets and the Terra Assets, to the Subject
Property and the Terra Property. Purchaser shall defend, indemnify and hold CMS,
and its successors and assigns, harmless from, against and in respect of any and
all Claims incurred by CMS by reason of damage or injury to any person or
property caused directly or indirectly as a result of Purchaser's inspection of
the Assets and the Terra Assets. Purchaser will treat and maintain as such any
Confidential Information it receives from CMS, Terra, or its Subsidiaries and
Affiliates in the course of the review contemplated by this Section 8.5, and
will not use any of the materials received from CMS, Terra, and its Subsidiaries
and Affiliates, or any information derived pursuant to this Section 8.5,
including, but not limited to, any Confidential Information, except in
connection with this Agreement. All materials reviewed and the results of all
tests, reviews, data and evaluations shall be maintained confidential through
the Closing Date. In the event the transaction contemplated by this Agreement is
not consummated for any reason whatsoever, then Purchaser shall immediately
provide all such tests, reviews, data and evaluations, and all written
materials, computer materials and other tangible embodiments related thereto to
CMS, and shall not maintain copies thereof, and shall maintain such materials,
tests, reviews, data and evaluations as Confidential Information, all in
accordance and consistent with Section 22.10. Purchaser will treat and hold as
such any Confidential Information it receives from CMS, Terra, or its
Subsidiaries in the course of the reviews contemplated by this Section 8.5, will
not use any of the Confidential Information except in connection with this
Agreement, and, if this Agreement is terminated for any reason whatsoever, will
return to the CMS, Terra, and its Subsidiaries all tangible embodiments (and all
copies) of the Confidential Information which are in its possession, all in
accordance with Section 22.10, below.

8.6     NOTICE OF DEVELOPMENTS


                                       31
<PAGE>   37


         CMS will give prompt written notice to Purchaser of any matter which
CMS discovers, or of which CMS is made aware, which causes, or with the passage
of time or the giving of notice, may cause any of the representations or
warranties set forth in Article IV and Article VI to be untrue, incorrect or
incomplete. Subject to the provisions of Sections 9.6 and 17.1(d), below, no
disclosures by CMS pursuant to this Section 8.6, however, shall be deemed to
prevent or cure any misrepresentation or breach of warranty.

                ARTICLE IX - PRE-CLOSING OBLIGATIONS OF PURCHASER

9.1      APPROVALS/CONSENTS

         During the Interim Period, Purchaser covenants and agrees it will
assist CMS in identifying and obtaining all permissions, approvals and consents,
of any governmental authorities or agencies as may be required to consummate the
transaction contemplated hereunder (excluding governmental permissions,
approvals and consents which are customarily obtained after the assignment of an
oil and gas lease or interest). The Parties shall cooperate to identify all such
permissions, approvals and consents in a timely manner so as to permit the
Closing to occur on or before the Closing Date. Except for an appropriate
adjustment to the Purchase Price, consistent with Attachment H, Purchaser shall
have no recourse against CMS with regard to any loss occasioned by the failure
to properly identify or timely notify any such permission, approval or consent.
Purchaser shall promptly notify CMS of any written claim received by Purchaser
from any third party relating to such permissions, approvals or consents.

9.2      BONDS AND PERMITS

         (a)      Attached hereto as Attachment J is a list of all bonds held by
                  CMS, or held by Terra and backed by CMS, relating to the
                  Assets and the Terra Assets. Purchaser has represented to CMS
                  that it or its designated operator, other than Terra, shall,
                  as of the Closing Date have all required federal, state and
                  local lease and operating bonds. Purchaser shall provide CMS
                  with satisfactory proof that the bonds are in full force and
                  effect for the Assets and the Terra Assets as of the Closing
                  Date or as soon thereafter as is reasonably possible.
                  Purchaser hereby covenants and agrees to defend, indemnify and
                  hold CMS, Terra, its parent, subsidiary and affiliate
                  entities, and CMS's and their officers, directors, employees
                  and agents, harmless from and against any and all Claims in
                  connection with any loss under or claims relating to any of
                  the bonds listed on Attachment J from and after the Effective
                  Date.

         (b)      Purchaser shall be responsible, and shall use its reasonable
                  best efforts to the extent that it has the ability, to confirm
                  or do all things necessary so that the transaction
                  contemplated by this Agreement does not cause the breach of
                  any terms or conditions of the Permits or the forfeiture or
                  impairment of any rights thereunder and that no consents,
                  approvals or acts of, or the making of any filing with, any
                  governmental body, regulatory commission or other party will
                  be required to be obtained in respect of any Permit as a
                  result of the consummation of the transaction


                                       32
<PAGE>   38


                  contemplated by this Agreement. CMS agrees to use its
                  reasonable commercial best efforts to cooperate with Purchaser
                  and to assist Purchaser to effectuate the foregoing.

9.3      CORPORATE DOCUMENTATION

         On or before the Closing Date, Purchaser shall provide CMS the
documents set forth in this Section 9.3. All documents shall be dated no earlier
than thirty (30) days before Closing.

         (a)      Certificate of Good Standing certified by the Secretary of
                  State for the state in which Purchaser is incorporated.

         (b)      A current statement, certified by the Secretary of State for
                  the State of Michigan, that Purchaser is authorized to do
                  business in the State of Michigan and is in good standing as a
                  foreign corporation.

         (c)      A copy of a resolution by the board of directors of Purchaser
                  authorizing the transaction intended by this Agreement and
                  authorizing the individual who executes this Agreement and any
                  conveyance instrument on behalf of the corporation to do so,
                  certified by the corporate secretary or assistant secretary of
                  Purchaser.

         (d)      A certificate of the secretary or assistant secretary of
                  Purchaser certifying the incumbency and specimen signature of
                  the officer of Purchaser who executes this Agreement and any
                  assignments or other documents required to be executed by
                  Purchaser, pursuant to the terms of this Agreement.

         (e)      If Purchaser is a partnership or other entity, Purchaser
                  agrees to provide CMS such documentation, as CMS requires to
                  verify Purchaser's status and the authority of its agent prior
                  to Closing.

9.4      NOTICES AND CONSENTS

         Purchaser will give any notice to, make any filings with, and use
commercially reasonable efforts to obtain any authorizations, consents and
approvals of governments and governmental agencies in connection with the
matters referred to in Sections 3.4(a) and 5.3, above, or required pursuant to
Section 5.7, above, if any.

9.5      NOTICE OF DEVELOPMENTS

         Purchaser will give prompt written notice to CMS of any material
adverse development causing a breach of any of its representations and
warranties contained in Article V, above. No disclosure by Purchaser pursuant to
this Section 9.5, however, shall be deemed to prevent or cure any
misrepresentation or breach of warranty.

9.6      NOTICE OF MISREPRESENTATION OR BREACH OF WARRANTY

         Purchaser will give prompt written notice to CMS of any matter which
Purchaser discovers, or of which Purchaser is made aware, which causes, or with
the passage of time or the giving of notice, may cause any of the



                                       33
<PAGE>   39

representations or warranties set forth in Article IV or Article VI to be
untrue, incorrect or incomplete. No disclosure by Purchaser pursuant to this
Section 9.6, however, shall be deemed to prevent or cure any misrepresentation
or breach of warranty, unless Purchaser fails to give CMS written notice of any
such matter known, discovered or disclosed to Purchaser within four (4) business
days after such matter becomes known by, discovered by or disclosed to
Purchaser, in which case any such misrepresentation or breach of warranty shall
be deemed waived or cured.

                     ARTICLE X - CMS'S CONDITIONS OF CLOSING

         CMS's obligation to consummate the transaction provided for herein is
subject to the satisfaction by Purchaser or waiver by CMS of the following
conditions set forth in Section 10.1 through Section 10.6, inclusive:

10.1     REPRESENTATIONS

         The representations and warranties of Purchaser contained in Article V
shall be true and correct in all material respects on the Closing Date as though
made on and as of that date.

10.2     PERFORMANCE

         Purchaser shall have performed in all material respects the
obligations, covenants and agreements to be performed by Purchaser at or prior
to the Closing.

10.3     PENDING MATTERS

         No suit, action or other proceeding by a third party or a governmental
authority shall be pending or threatened which seeks substantial damages from
CMS in connection with, or seeks to restrain, enjoin or otherwise prohibit, the
consummation of the transaction contemplated by this Agreement.

10.4     WAITING PERIODS

         All applicable waiting periods (and any extensions thereof) under any
applicable act shall have expired or otherwise been terminated and the Parties,
Terra, and its Subsidiaries shall have received all other authorizations,
consents, and approvals of governments and governmental agencies referred to in
Sections 4.4, 5.5 and 6.3, above.

10.5     OPINION OF COUNSEL

         CMS shall have received an Opinion of Counsel, dated as of Closing,
from Purchaser's counsel, in form and substance as set forth at Attachment N.

10.6     PAYMENT OF PURCHASE PRICE OR ADJUSTED PURCHASE PRICE

         Purchaser shall have wire transferred to CMS the Purchase Price or
Adjusted Purchase Price due at Closing as described in Section 3.4(b), above,
pursuant to written instructions delivered by CMS.

         CMS may waive any condition specified in this Article X, by executing a
statement to that effect at or prior to Closing.


                                       34
<PAGE>   40


                 ARTICLE XI - PURCHASER'S CONDITIONS OF CLOSING

                  Purchaser's obligation to consummate the transaction provided
for herein is subject to the satisfaction by CMS or waiver by Purchaser of the
following conditions set forth in Sections 11.1 through 11.5, inclusive:

11.1     REPRESENTATIONS

         The representations and warranties of CMS contained in Article IV,
except Section 4.13, and in Sections 6.2, 6.3, 6.5, 6.7, 6.8(w), 6.10, 6.12,
6.14, 6.15, 6.18, and 6.19 shall be true and correct in all material respects on
the Closing Date as though made on and as of that date.

11.2     PERFORMANCE

         CMS shall have performed in all material respects the obligations,
covenants and agreements to be performed by it at or prior to the Closing.

11.3     PENDING MATTERS

         No suit, action or other proceeding by a third party or a governmental
authority shall be pending or threatened which seeks substantial damages from
Purchaser in connection with, or seeks to restrain, enjoin or otherwise
prohibit, the consummation of the transaction contemplated by this Agreement.

11.4     WAITING PERIODS

         All applicable waiting periods (and any extensions thereof) under any
applicable act, shall have expired or otherwise been terminated and the Parties,
Terra, and its Subsidiaries shall have received all other authorizations,
consents, and approvals of governments and governmental agencies referred to in
Sections 4.4, 5.5 and 6.3, above.

11.5     OPINION OF COUNSEL

         Purchaser shall have received an Opinion of Counsel, dated as of
Closing from CMS's counsel, in form and substance as set forth at Attachment O.

         Purchaser may waive any condition specified in this Article XI, by
executing a statement to that effect at or prior to Closing.

                      ARTICLE XII - ENVIRONMENTAL CONDITION

12.1     EXISTING CONDITION

         The Subject Property and the Terra Property have been utilized by CMS,
Terra and/or its Subsidiaries and possibly others for the purposes of
exploration, development, production and transportation of oil and gas.
Purchaser acknowledges that wastes and products, including, but not limited to,
crude oil, natural gas, natural gas liquids, produced water, and other wastes
associated with oil and gas production and exploration operations, may have been
spilled, released or disposed of on-site by, among other ways, placement in
pits, burial, land farming, land spreading and underground injection, into or
onto the Subject Property and the Terra Property. Purchaser acknowledges that
some oilfield production equipment located on the Subject Property and the Terra
Property may contain asbestos or naturally-


                                       35
<PAGE>   41

occurring radioactive material ("NORM"). Purchaser expressly understands that
NORM may affix or attach itself to the inside of wells, materials and equipment
as scale or in other forms, and that wells, materials and equipment located on
the Subject Property and the Terra Property may contain NORM and that
NORM-containing materials may be buried or have been otherwise disposed of on
the Subject Property and the Terra Property. Purchaser also expressly
understands that special procedures may be required for the removal and disposal
of asbestos and NORM from the equipment and the Subject Property and the Terra
Property where it may be found.

         Attachment P contains a list of those portions of the Subject Property,
the Terra Property and other properties for which CMS has responsibility or
liability which, to the Knowledge of CMS constitute a "Facility", as defined in
1994 PA No. 451, Sec. 20101(o), and discloses the general nature and extent of
any release. Attachment P is intended to, and shall constitute notice to
Purchaser of the existence of any such Facility, as may be required by 1994 PA
No. 451, Sec. 20116. In the event the transaction contemplated by this Agreement
proceeds to closing, then as of the Effective Date Purchaser shall assume all
responsibility and all liability of CMS with respect to all Environmental,
Health and Safety Requirements relating to the Facilities listed at Attachment
P, and Purchaser agrees to release, defend, indemnify and hold CMS, its parent,
affiliate and subsidiary corporations, as well as CMS's and their officers,
directors, shareholders, employees and agents, harmless from and against any and
all Claims and Adverse Consequences of whatsoever kind and nature arising out of
the matters identified at Attachment P.

12.2     ENVIRONMENTAL ASSESSMENT AND ACCESS

         (a)      For the purposes of this Agreement, an "Environmental
                  Assessment" shall mean the right to enter upon and within the
                  Subject Property and the Terra Property, and to inspect the
                  structures and improvements thereon. An Environmental
                  Assessment shall be a Phase I environmental review only, which
                  shall only consist of (i) a review and assessment of the
                  adequacy of CMS's or Terra's existing permits for the Subject
                  Property and the Terra Property; (ii) a review of historic
                  data to determine prior land uses; (iii) a compilation of
                  pertinent information related to the Subject Property and the
                  Terra Property, including interpretation of analytical data in
                  the files referenced in Section 1.1(h), above, except any such
                  information which CMS considers to be confidential or
                  proprietary or which CMS or Terra is prohibited from
                  disclosing due to third party restrictions unless such
                  information is directly related to the condition, quality or
                  quantity of the Subject Property or the Terra Property; (iv) a
                  physical examination of the Subject Property and the Terra
                  Property to identify potential contaminant sources; and (v)
                  surveys to locate the boundaries of the Subject Property and
                  the Terra Property.

         (b)      Environmental Assessment shall not include soil boring,
                  collection of samples or analysis of any material on the
                  Subject Property and the Terra Property without the express
                  written consent of CMS. If Purchaser performs any borings,
                  collects samples or performs analysis of material, Purchaser
                  shall assume all liability of the results, generation of
                  wastes and disposal of any material generated. Purchaser shall
                  release, defend, indemnify and hold CMS its parent, affiliate
                  and subsidiary corporations, as well as CMS's officers,
                  directors, shareholders,


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<PAGE>   42

                  employees and agents harmless from, against and in respect of
                  any and all Claims created by or associated with boring,
                  sampling or analysis.

         (c)      Following execution of this Agreement, and upon reasonable
                  notice to CMS, Purchaser shall have the right, until fifteen
                  (15) business days preceding the Closing Date, to conduct or
                  have conducted an Environmental Assessment of the Subject
                  Property and the Terra Property at its sole cost, risk and
                  expense. Purchaser shall provide CMS a copy of the
                  Environmental Assessment, including any reports, data and
                  conclusions prior to Closing. CMS agrees to provide Purchaser
                  with reasonable access to the Subject Property and the Terra
                  Property to conduct the Environmental Assessment. CMS shall
                  have the right to require Purchaser to conform to CMS's safety
                  and industrial hygiene procedures in the performance of the
                  Environmental Assessment.

         (d)      In the event Purchaser's Environmental Assessment reveals a
                  demonstrable violation of any Environmental, Health or Safety
                  Requirements (other than those matters disclosed at Attachment
                  P), then Purchaser shall so notify CMS in writing, no later
                  than fifteen (15) business days prior to Closing. In the event
                  that Purchaser timely and properly asserts a violation of any
                  Environmental, Health or Safety Requirements, such violation
                  shall be resolved in accordance with the procedure contained
                  in Section 17.1(d), below, or CMS, at its sole and exclusive
                  option, may elect to exclude the affected portion of the
                  Subject Property or the Terra Property, from the transaction
                  contemplated by this Agreement with a corresponding downward
                  adjustment to the Purchase Price in an amount equal to the
                  allocated value of the affected portion of the Subject
                  Property or the Terra Property, as reflected at Attachment H.
                  In the event a portion of the Terra Property is excluded from
                  the transaction contemplated by this Agreement, CMS shall
                  cause Terra to assign all of its right, title and interest in
                  the affected portion of the Terra Property to CMS, at or prior
                  to Closing.

12.3     RELEASE AND INDEMNITY FOR ENVIRONMENTAL CONDITIONS

         Purchaser understands that upon Closing the conveyance and assignment
of the Subject Property and the Terra Property will be on an "AS IS" and "WHERE
IS" basis, "WITH ALL FAULTS". Purchaser shall assume and discharge any and all
liabilities with respect to Environmental, Health and Safety Requirements
relating to the ownership or operation of the Assets and the Terra Assets
whether arising before or after the Effective Date, except as follows:

         (i)      Purchaser assumes no liability with respect to Environmental
                  Health and Safety Requirements unless and until Closing
                  occurs; and

         (ii)     Except as qualified by Section 18.1, below, Purchaser assumes
                  no liability with respect to any matters which constitute a
                  breach of the representations and warranties of CMS contained
                  in Section 4.8 and Section 6.12 , above.

         Subject to the provisions of Article XVIII below, as to all other
Environmental, Health and Safety Requirements, Purchaser hereby releases and
shall and does hereby covenant and agree to defend, indemnify and hold CMS, its
parent, subsidiary and affiliate corporations, and CMS's and their officers,
directors, employees and agents harmless from and against any and


                                       37
<PAGE>   43


all Claims and Adverse Consequences with respect to or related in any manner to
any and all Environmental, Health and Safety Requirements of, or any other
condition of the Subject Property or the Terra Property existing either before
or after the Effective Date or Closing Date. Purchaser agrees that the indemnity
provision of this Section 12.3 shall apply regardless of whether CMS or Terra
was wholly or partially, actively or passively, negligent or otherwise at fault,
and whether or not the Claim or Adverse Consequence is based on a theory of
negligence, negligence per se, strict liability, willful misconduct, products
liability, premises liability or other theory of liability as to the applicable
indemnitee or others.

12.4     CONFIDENTIALITY, RELEASE AND INDEMNITY FOR ENVIRONMENTAL ASSESSMENT

         Purchaser agrees that any data, the results of any analysis of data or
information acquired pursuant to the Environmental Assessment shall be deemed to
be Confidential Information subject to the provisions of Section 22.10, below.
Purchaser will not disclose the data, analysis or information to any person or
agency without the prior written approval of CMS. Purchaser waives and releases
all Claims against CMS, its parent, subsidiary and affiliate corporations, and
CMS's and their directors, officers, employees and agents, and to the extent CMS
or Terra may have any liability or duty of contribution, CMS's and Terra's
working interest owners, partners or joint venturers in the Subject Property and
the Terra Property, for any injury to, disease of, or death of persons, or
damage to or loss of property arising in any way from the exercise of
Purchaser's right to conduct the Environmental Assessment, or activities of
Purchaser or its employees or agents on the Subject Property and the Terra
Property while conducting the Environmental Assessment. Purchaser shall defend,
indemnify and hold harmless CMS, its parent, subsidiary and affiliate
corporations, and CMS's and their directors, officers, employees and agents, and
to the extent CMS or Terra may have any liability or duty of contribution, CMS's
and Terra's lessors, co-lessees, co-working interest owners, joint venturers and
partners in the Subject Property and the Terra Property (insofar only as CMS or
Terra may be obligated to such lessors, co-lessees, co-working interest owners,
joint venturers and partners), harmless from and against any and all Claims and
Adverse Consequences whatsoever, and any and all statutory or common law liens
or other encumbrances for labor or materials furnished in connection with the
Environmental Assessment, and the disposition of any samples or wastes generated
by the Environmental Assessment. Purchaser agrees that it shall be considered to
be the sole generator of any wastes or samples generated by the Environmental
Assessment, and that it shall comply with all applicable federal, state or local
governmental laws, rules, regulations and ordinances in conducting the
Environmental Assessment.

12.5     INSURANCE FOR ENVIRONMENTAL ASSESSMENT

         Purchaser shall obtain and maintain comprehensive public liability and
property damage insurance for the performance of the Environmental Assessment by
Purchaser or its contractor or other agents, or for purposes of obtaining
physical access to any of the Subject Property and the Terra Property, or for
any other purpose prior to Closing. The insurance shall: (i) be obtained from
and maintained with an insurer acceptable to CMS; (ii) shall have limits of not
less than one million dollars ($1,000,000) per occurrence for death or injury
and property damage, and five hundred thousand dollars ($500,000) for workers
compensation; (iii) cover Purchaser's obligations under the indemnity provisions
of this Article XII and Section 16.3; (iv) shall be occurrence-based insurance;
(v) shall name CMS as an additional insured; (vi) shall contain a waiver of
subrogation rights as to CMS; and (vii) shall contain a provision pursuant to
which the insurer agrees not to cancel or modify the

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<PAGE>   44
insurance coverage without furnishing at least thirty (30) days' prior written
notice to CMS. Prior to the exercise of any right to gain access to the Subject
Property and the Terra Property, Purchaser shall furnish CMS a certificate
evidencing the existence of the insurance required pursuant to this Section
12.5.

12.6 INDEMNITY REGARDING ACCESS

         Purchaser hereby releases and shall and does hereby covenant and agree
to defend, indemnify and hold CMS, Terra and its Subsidiaries, its parent,
subsidiary and affiliate corporations, and CMS's and their officers, directors,
employees and agents, and to the extent CMS or Terra may have any liability or
duty of contribution, CMS's and Terra's lessors, co-lessees, co-working interest
owners, partners and co-venturers (insofar only as CMS or Terra may be obligated
to such lessors, co-lessees, co-working interest owners, joint venturers or
partners) in the Subject Property and the Terra Property, harmless from and
against any and all Claims and Adverse Consequences in connection with personal
injuries, including death, or property damage or loss arising out of or relating
to access to the Subject Property or the Terra Property by Purchaser, its
officers, directors, employees, agents and representatives to inspect the
Subject Property and the Terra Property, including access to the Subject
Property and the Terra Property for performing an Environmental Assessment. This
indemnity obligation includes any access to the Subject Property and the Terra
Property prior to Purchaser's execution of this Agreement, up through the later
of the Closing Date and the date upon which CMS relinquishes operatorship of any
of the Assets or the Terra Assets, for any purpose relating to the acquisition
or proposed acquisition by Purchaser of the Assets and the Terra Assets. The
indemnity obligations of Purchaser under this Section 12.6 shall survive the
Closing or termination of this Agreement.

                        ARTICLE XIII - TITLE EXAMINATION

13.1 TITLE EXAMINATION PERIOD

         Following execution of this Agreement, Purchaser shall have until July
31, 2000 (the "Extended Due Diligence Period") to complete, at Purchaser's sole
cost, risk and expense, all title examinations of the Subject Property and the
Terra Property. On or before the expiration of the Extended Due Diligence
Period, Purchaser shall deliver written notice to CMS ("Claim of Title Defect")
of any claim that CMS's or Terra's title within the presently producing
formations of the Subject Property and the Terra Property is less than
"Defensible Title," as defined in Section 13.6, below. The Claim of Title Defect
shall detail the specific portion(s) of the Subject Property or the Terra
Property affected, and specify any "Title Defect" (as defined at Section 13.8)
which causes title to the specific portion of the Subject Property or the Terra
Property to be less than Defensible Title. Such written notice shall specify all
available information, including but not limited to the action Purchaser deems
necessary for CMS, if it so elects, to cure title so as to allow CMS to deliver
Defensible Title. Any Title Defect as to which Purchaser does not assert a Claim
of Title Defect to CMS within the Extended Due Diligence Period, shall be deemed
waived for all purposes. Purchaser shall be solely responsible for any costs of
title examination, title curative actions (other than those referenced in
Section 13.2, below), landman or broker fees, document preparation and of any
inspections it undertakes, and CMS shall not have to create, update or
supplement any title documents, such as abstracts of title or title opinions, in
its possession. Purchaser will not be given access to data and records which CMS
considers to be proprietary or confidential to it, or which CMS or Terra cannot
legally


                                       39
<PAGE>   45

provide Purchaser because of third party restriction on CMS or Terra, unless
such data or records are directly related to the condition, quality or quantity
of the Subject Property or the Terra Property. During the Extended Due Diligence
Period CMS may deliver written notice to Purchaser claiming upward adjustments,
in accordance with Section 3.3(b), below, as the result of the interest of CMS
in a specific portion of the Subject Property or the Terra Property being
greater than that set forth at Attachment A.

13.2 CURE OF TITLE

         CMS shall review any Claim of Title Defect submitted in accordance with
Section 13.1, above, with the option (at CMS's sole cost and expense) of curing
any Title Defect properly identified in the Claim of Title Defect. CMS shall
also have the option, but not the obligation to indemnify Purchaser or bond over
any alleged Title Defect, in an amount equal to the diminishment in value of the
affected portion of the Subject Property or the Terra Property caused by such
Title Defect determined in accordance with Section 13.4. If CMS so elects to
indemnify Purchaser or bond over a Title Defect, then Purchaser shall take or
retain title to the affected portion of the Subject Property or the Terra
Property, subject to the Title Defect, without any downward adjustment to the
Purchase Price.

13.3 TITLE ADJUSTMENTS

         (a)      Downward Adjustment. If on or before September 30, 2000, CMS
                  shall not have cured any Title Defect affecting the Subject
                  Property or the Terra Property for which a Claim of Title
                  Defect was properly and timely made, and CMS has elected not
                  to indemnify Purchaser against or bond over the alleged Title
                  Defect, then subject to Section 13.5, below, CMS shall pay to
                  Purchaser an amount equal to the diminishment in value
                  represented by such Title Defect, determined in accordance
                  with Section 13.4,below.

         (b)      Upward Adjustment. If on or before September 30, 2000, the
                  Parties shall determine that, (i) CMS or Terra owns a greater
                  net revenue interest than is set forth at Attachment A as to
                  the oil and gas produced, saved and marketed from the
                  presently producing formations in any of the individual
                  producing well(s) or unit(s) described at Attachment A, (ii)
                  CMS or Terra owns a greater net revenue interest, as to all
                  unitized, pooled or communitized substances presently
                  producing from the applicable unitized, pooled, or
                  communitized formation(s) within the applicable unitized,
                  pooled or communitized area(s) allocated to any of the
                  interest(s) set forth at Attachment A, or (iii) CMS's or
                  Terra's share of expenses or burdens attributable to the oil
                  and gas produced, saved and marketed from the presently
                  producing formations in any of the individual producing
                  well(s) or unit(s) described at Attachment A is less than
                  shown at Attachment A, without a corresponding reduction in
                  CMS's or Terra's net revenue interest, then CMS shall send
                  written notice thereof to Purchaser prior to September 30,
                  2000. The notice shall state the specific interest(s) affected
                  and indicate the amount of increase to the net revenue
                  interest, or decrease in the expenses or burdens, and specify
                  the reason(s) for the upward adjustment. The Purchase Price
                  shall be adjusted upward by, or Purchaser shall pay to CMS,
                  the increased value of the Assets and the Terra Assets as a
                  result of the increased net revenue interest, or decreased
                  expenses or burdens, determined consistent with Section 13.4,


                                       40
<PAGE>   46

                  below. In determining whether an upward adjustment is called
                  for under this Section 13.3(b), neither CMS nor Terra shall be
                  deemed to own an interest that such party holds for the
                  benefit of a third party.

         Any downward or upward adjustment may be accounted for in the Final
Settlement Statement, in the manner provided in Section 16.1, below.

13.4 VALUE OF TITLE ADJUSTMENTS

         The diminishment in value of the Assets or the Terra Assets resulting
from an asserted Title Defect, as well as the amount of any and all upward
adjustments provided for by Section 13.3(b), above, shall be consistent with the
following:

         (a)      If a Title Defect is a valid and enforceable lien, encumbrance
                  or other charge, which is liquidated in amount, the value of
                  the downward adjustment in the Purchase Price shall be the sum
                  necessary to be paid to the lienholder to remove the Title
                  Defect from the portion of the Subject Property or the Terra
                  Property affected by the Title Defect.

         (b)      If a Title Defect represents an obligation or burden upon the
                  Subject Property or the Terra Property for which the economic
                  detriment to Purchaser is not liquidated but can be estimated
                  with reasonable certainty, the value of the downward
                  adjustment in the Purchase Price shall be a sum necessary to
                  compensate Purchaser for the present value of the adverse
                  economic effect which the Title Defect will have on the
                  Subject Property or the Terra Property.

         (c)      A lien or encumbrance in the form of a judgment secured by a
                  supersedeas bond or other security approved by the court
                  issuing the judgment shall not be considered a Title Defect
                  and no adjustment to the Purchase Price will be made.

         (d)      If the Title Defect proves CMS or Terra owns a lesser net
                  revenue interest than that shown at Attachment A, or a greater
                  working interest than that shown at Attachment A, without a
                  corresponding proportionate increase in the net revenue
                  interest attributable to an interest in an oil and gas lease,
                  the amount of the downward adjustment to the Purchase Price
                  shall be the value of the decrease in the net revenue interest
                  or increase in the working interest, consistent with the
                  allocations of value set forth at Attachment H, which is
                  allocated to the applicable interest in an oil and gas
                  lease(s) affected by the Title Defect.

         (e)      Subject to Section 13.5, below, in no event shall the value of
                  any Title Defect alleged by Purchaser exceed the value
                  attributed to the interest affected, as set forth on
                  Attachment H.

         (f)      If it is determined that there is an upward adjustment in
                  accordance with Section 13.3(b), above, the amount of the
                  upward adjustment to the Purchase Price shall be the value of
                  the increase in the net revenue interest or decrease in the
                  working interest, consistent with the allocations of value set
                  forth at Attachment H, which is allocated to the applicable
                  interest in an oil and gas lease(s) affected.

                                       41
<PAGE>   47

13.5 LIMITS ON TITLE ADJUSTMENTS

         Any other provisions of this Agreement to the contrary notwithstanding
in the event the total cumulative title adjustments do not exceed the sum of
three hundred thousand dollars ($300,000.00), there shall be no adjustment to
the Purchase Price for Title Defects, and in no event shall any adjustment be
made for the first $300,000.00 in Title Defects alleged by Purchaser, or upward
adjustment due CMS, regardless of whether the cumulative downward or upward
adjustment exceeds that amount. Further, neither CMS nor Purchaser shall assert
any Title Defects or upward adjustments provided for in this Article XIII, the
value of which, determined in accordance with Section 13.4, above, and
Attachment H, is ten thousand dollars ($10,000.00) or less.

13.6 DEFINITION OF DEFENSIBLE TITLE

         The term "Defensible Title" shall have the meaning as follows: (i) as
to each interest in an oil and gas lease, (or if any such lease is included in a
production unit, then as to such unit) comprising the Assets or the Terra
Assets, Defensible Title is that which entitles CMS or Terra on a leasehold
basis to receive not less than the net revenue interest set forth at Attachment
A for all oil and gas produced, saved and marketed from the presently producing
formations in the Subject Property and the Terra Property as of the Effective
Date; (ii) as to each interest in an oil and gas lease (or if any such lease is
included in a production unit, then as to such unit) comprising the Assets or
the Terra Assets, Defensible Title is that which obligates CMS or Terra on a
leasehold basis to bear costs and expenses relating to the maintenance,
development and operation of the producing wells and units on leased lands and
depths not exceeding the working interest described at Attachment A as of the
Effective Date; and (iii) as to the Assets and the Terra Assets, Defensible
Title is that which as of the Effective Date is marketable title, and as to
those portions of the Assets and Terra Assets which constitute interests in real
property, marketable record title, free and clear of material encumbrances,
liens and defects, other than Permitted Encumbrances, as defined below.

13.7 DEFINITION OF PERMITTED ENCUMBRANCES

         The term "Permitted Encumbrances" shall include all of the conditions
of title contained in this Section 13.7 as follows:

         (a)      Permitted Encumbrances include lessors' royalties, overriding
                  royalties, reversionary interests and similar burdens on any
                  leasehold working interests described at Attachment A, if the
                  net cumulative effect of the burdens does not operate to
                  reduce CMS's or Terra's interest in all oil and gas produced
                  from the leasehold interests below the net revenue interest on
                  a leasehold basis as set forth at Attachment A;

         (b)      Permitted Encumbrances include division orders and sales
                  contracts terminable without penalty upon no more than ninety
                  (90) days' notice to the purchaser;

         (c)      Permitted Encumbrances include unexercised preferential rights
                  to purchase, which have been waived or for which the time to
                  exercise has expired, required third party consents to
                  assignments, which have been waived or obtained, and similar
                  agreements;

                                       42
<PAGE>   48

         (d)      Permitted Encumbrances include materialmen's, mechanics',
                  operators', co-working interest owners', repairmen's,
                  employees', contractors', tax and other liens and charges,
                  arising in the Ordinary Course of Business, which have not
                  been filed in compliance with statutes, or, if filed, have not
                  become delinquent or payment is being withheld as provided by
                  law or agreement or the validity of which is being contested
                  in good faith by appropriate action, encumbrances, contracts,
                  agreements, instruments, and obligations, affecting the Assets
                  or the Terra Assets arising in the Ordinary Course of
                  Business;

         (e)      Permitted Encumbrances include all rights to, consent by,
                  required notices to, filings with or other actions by
                  governmental entities in connection with the sale or
                  conveyance of oil and gas leases or interests which are
                  customarily obtained subsequent to the sale or conveyance;

         (f)      Permitted Encumbrances include easements, rights-of-way,
                  servitudes, permits, surface leases and other rights for
                  surface operations, pipelines, grazing, logging, canals,
                  ditches, reservoirs or similar surface uses, conditions,
                  covenants or other restrictions, easements for streets,
                  alleys, highways, pipelines, telephone lines, power lines,
                  railways and other easements and rights-of-way, on, over or in
                  respect of any of the Subject Property or the Terra Property;

         (g)      Permitted Encumbrances include all rights reserved to or
                  vested in any governmental, statutory or public authority to
                  control or regulate any of the Assets or the Terra Assets in
                  any manner, and all applicable laws, rules and orders of
                  governmental authority;

         (h)      Permitted Encumbrances include any Title Defects which
                  Purchaser may have expressly waived in writing or which are
                  deemed to have been waived under this Agreement;

         (i)      Permitted Encumbrances include any production imbalances and
                  pipeline imbalances;

         (j)      Permitted Encumbrances include (whether or not recorded), all
                  leases, unit agreements, communitization agreements, pooling
                  agreements, governmental orders and other contracts and
                  agreements, to which CMS or Terra is a party, or to which CMS
                  or Terra or the Assets or the Terra Assets are subject, and
                  all assignments of the Subject Property or the Terra Property,
                  and all required consents or rights of reassignment provided
                  for by any of the foregoing, to the extent the same do not
                  operate to reduce CMS's or Terra's net revenue interest below
                  that specified at Attachment A, or to increase the obligations
                  of CMS or Terra to bear costs and expenses in excess of the
                  working interest specified at Attachment A, without a
                  corresponding increase in the net revenue interest. Permitted
                  Encumbrances does not include mortgages, liens or encumbrances
                  other than those that are the subject of Section 13.7(d),
                  above.

13.8 DEFINITION OF TITLE DEFECT

         The term "Title Defect" means any material encumbrance, encroachment,
irregularity, defect in or objection to CMS's or Terra's title to the Subject
Property and the Terra Property listed at Attachment A which, alone or in


                                       43
<PAGE>   49

combination with other defects, renders CMS's or Terra's title to the Subject
Property or the Terra Property less than Defensible Title. In determining
whether an encumbrance, encroachment, irregularity, defect in or objection to
title is material, due consideration shall be given to the length of time that
the interest involved has been, is or is considered to be in "Pay Status" and
whether the Title Defect is of the type expected to be encountered in the area
involved and is customarily acceptable to prudent operators and interest owners.
An interest shall be considered to be in Pay Status when payment is being made,
whether by CMS, Terra or its Subsidiaries or by a third party, for the
production from or that is otherwise allocated to the Subject Property or the
Terra Property without indemnity from CMS or Terra, except indemnity customarily
made in division orders, transfer orders, product purchase agreements and
similar documents governing the payment of proceeds from production. Title
Defects, which are not material, include, without limitation, defects that have
been cured by possession under applicable statutes of limitation, defects in the
early chain of title such as failure to recite marital status in documents,
omission of heirship or succession proceedings, lack of survey, failure to
record releases of oil and gas leases, failure to obtain subordination of a
lessor mortgage to an oil and gas lease, liens, production payments or mortgages
that have expired of their own terms, matters which are deemed remedied, cured
or otherwise satisfied by the remedial effects of the Michigan Forty Year
Marketable Title Act (MCL 565.101 to 565.109, inclusive; MSA 26.1271 to 26.1279,
inclusive), and matters that are not reasonably expected to result in claims
adversely affecting CMS's or Terra's title to the Subject Property or the Terra
Property. The term Title Defects does not include Permitted Encumbrances.
Matters which occur during the Interim Period and which result in a reduction in
the net revenue, or an increase in the working interest without a corresponding
increase in net revenue interest of CMS or Terra in and to a portion of the
Assets or Terra Assets from that which is shown at Attachment A shall not form
the basis for the assertion of a Title Defect, and shall be deemed Defensible
Title to the affected Asset or Terra Assets, if such matter is the result of an
event or occurrence which is in the Ordinary Course of Business, or is beyond
the control of CMS or Terra.

13.9 BACK-IN INTEREST ADJUSTMENTS

         For purposes of this Section 13.9 the term "Reserve Report" means the
report entitled "Estimated Future Reserves And Income Attributable To Certain
Leasehold And Royalty Interests Beginning January 1, 2000", bearing date of
October 25, 1999, prepared by Ryder Scott Company for CMS, which was made
available to Purchaser. Among other things, the Reserve Report specifies the
Expense Interest (working interest) and the Revenue Interests (net revenue
interests) of CMS and/or Terra in the various individual producing wells and
units, and the various unitized, pooled or communitized areas or units that
comprise the Assets and the Terra Assets, these being the same wells, units and
areas described at Attachment A1 ("Constituent Property or Properties"). The
Reserve Report reflects the Expense Interest and Revenue Interests of CMS and/or
Terra in each Constituent Property at two points in time. The "Initial" interest
is that owned as of January 1, 2000. The "Final" interest, if different than the
Initial interest, reflects an increase or decrease that will occur at an
unspecified time in the future as the result of the provisions of applicable
contracts. The Parties acknowledge and agree that the Reserve Report valuation
is a function of both the Initial and Final Interests.

         For purposes of this Section 13.9, the term "Back-In Interests" means,
with respect to a particular Constituent Property, the working and net revenue
interests actually owned by CMS and/or Terra which correlate to the Final
interests shown on the Reserve Report. Notwithstanding anything in Article XIII
to the contrary, the Parties acknowledge and agree that if it is determined by
either Party, within the Extended Due Diligence Period, that the Back-In
Interests owned by CMS and/or Terra in a given Constituent Property vary from
the Final interests as represented in the Reserve Report, such variance shall
constitute a Title Defect if the Reserve Report reflects a larger Final Revenue
Interest than the amount of the Back-In Interests) or the basis for an upward
adjustment in accordance with Section 13.3(b), above, (if the Reserve Report
reflects a smaller Final Revenue Interest than the


                                       44
<PAGE>   50

amount of the Back-In Interest) for which a corresponding title adjustment will
be made, whether upwards or downwards, in accordance with the remaining
provisions of this Section 13.9.

         A Title Defect asserted under this Section 13.9 with respect to a
Back-In Interest, shall be subject to the same limitations and requirements
imposed by Section 13.1, above, shall be subject to the right of CMS to cure,
indemnify against or bond over, in accordance with Section 13.2, above, and both
Title Defect adjustments and upward adjustment shall be subject to the same
limitations as imposed by Section 13.5, above; provided, however, that in the
event of conflict this Section 13.9 shall govern and control. The value of any
title adjustment, for any Title Defect or upward adjustment asserted under this
Section 13.9 with regard to a Back-In Interest, shall be negotiated by the
Parties in good faith. In negotiating the value of any resulting title
adjustment, among other things, the Parties shall consider and take into account
the provisions of Sections 13.3 and 13.4, above; provided, however, that the
basis for any title adjustment made with respect to a Back-In Interest, in
accordance with this Section 13.9, shall be the value attributed to the
particular Constituent Property by the Reserve Report, reduced by applying a
fraction having a numerator of 161,241,694 and a denominator of 177,337,178.

13.10 REPRESENTATIONS, WARRANTIES OR COVENANTS, AND INDEMNITY

         The provisions of this Article XIII shall be deemed to be, and shall
constitute representations, warranties and covenants of title by CMS that will
continue until the expiration of the Extended Due Diligence Period and as to
Title Defects timely and properly asserted, thereafter as provided below.
Subject to the limitations contained in Section 13.5, above, CMS hereby
covenants and agrees to defend, indemnify and hold Purchaser harmless from and
against any and all Claims with respect to or related in any manner to any and
all Title Defects for which Purchaser has timely and properly delivered a Claim
of Title Defect to CMS, consistent with Sections 4.13, 6.16 and 13.9, above, as
qualified by Section 18.1, below. Any and all such representations and
warranties of CMS relating to any and all title matters shall expire and be of
no further force and effect from and after the later of (i) the end of the
Extended Due Diligence Period or (ii) such time as a Title Defect for which a
Claim of Title Defect is properly and timely asserted, is cured, CMS indemnifies
Purchaser, CMS bonds over the Title Defect or a title adjustment is made in
accordance with Section 13.3(a), above. If a Title Defect adjustment is made
pursuant to Section 13.3(a), above, or CMS indemnifies or bonds over a Title
Defect, pursuant to this Article XIII, it shall be Purchaser's sole remedy for
any such Title Defect. All of the Assets and the Terra Assets for which CMS
indemnifies Purchaser or bonds over, shall be transferred to Purchaser at
Closing, and shall be retained by Purchaser after the expiration of the Extended
Due Diligence Period. As to all Assets or Terra Assets for which a Title Defect
adjustment is made, CMS shall be entitled to a conveyance from Purchaser, and
Purchaser hereby agrees to convey to CMS, in recordable form, free and clear of
any liens or claims of Purchaser, or any Person claiming through Purchaser, the
Asset(s) or Terra Asset(s), or portion of either affected by the asserted Title
Defect if the asserted Title Defect consists of failure of title to the Asset or
the Terra Asset, or a portion thereof. CMS shall not be entitled to a conveyance
of the affected Asset or Terra Asset if the asserted Title Defect is in the
nature of a mortgage, lien or other encumbrance which may be cured by the
payment of a determinable sum of money. The instruments of conveyance (to be
recorded in the applicable county records) shall not include references to the
specific working interest, overriding royalty or the net revenue interest
conveyed or assigned per the terms of this Agreement, nor shall such instrument
or conveyance contain any warranty of title, but they shall reference and be
made subject to the terms of this Agreement, and the terms of the letter
agreement referenced in Section 15.2(b), below. Anything to the contrary
contained herein notwithstanding, all Title Defects not timely raised by
Purchaser shall be deemed waived for all purposes, and Purchaser shall have no
recourse as against CMS from and


                                       45
<PAGE>   51

after the expiration of the Extended Due Diligence Period. In the event an
adjustment to the Purchase Price is made in the Final Settlement Statement
pursuant to this Article XIII, or a Title Defect is otherwise deemed waived,
Purchaser shall have no further rights or remedies against CMS with respect to
any Title Defect, other than a claim pursuant to an indemnity or bond of CMS.

13.11 ARBITRATION

         In the event that the Parties are unable, after good faith
negotiations, to resolve any disagreement with respect to any asserted Title
Defect, or any proposed adjustment provided for in this Article XIII, then the
Parties agree to resolve all such disagreements through binding arbitration.
Each Party shall select an arbitrator with experience evaluating oil and gas
title matters, and the arbitrators shall select a third such arbitrator, to
arbitrate any such unresolved disputes in accordance with the rules of the
American Arbitration Association. The decision of the arbitrators shall be
binding on the Parties, and their successors and assigns.

                       ARTICLE XIV - RETAINED LIABILITIES

         Attachment D lists all wells, litigation and other matters relating to
the Assets and the Terra Assets which constitute the Retained Liabilities. CMS
shall retain responsibility and liability for, and authority and control over
the Retained Liabilities and all actions, which, in its sole discretion are
necessary or desirable related to the Retained Liabilities, including but not
limited to the prosecution, defense, settlement or other resolution of those
matters constituting litigation, and shall be solely responsible for all costs
associated therewith. Purchaser shall and does hereby grant CMS, its officers,
directors, employees, agents and attorneys, access to and use of the Assets and
Terra Assets, including, but not limited to the Subject Property and the Terra
Property, and the records referenced in Section 1.1(h), above, for any and all
purposes related to the Retained Liabilities.


         CMS hereby covenants and agrees to defend, indemnify and hold Purchaser
harmless from and against any and all Claims and Adverse Consequences with
respect to the Retained Liabilities, insofar only as the event that forms the
basis of the Claims or Adverse Consequences arose or occurred prior to the
Effective Date. Notwithstanding the foregoing, the preceding indemnity provision
shall survive until the event giving rise to the Claim or Adverse Consequences
is resolved.

                              ARTICLE XV - CLOSING

15.1. TIME AND PLACE OF CLOSING

         If the conditions of Closing referenced in Article X and Article XI,
have been satisfied or waived, the consummation of the transaction contemplated
hereby (the "Closing") shall be held on or before the 31st day of March, 2000
(the "Closing Date") at CMS's offices in Houston, Texas, unless otherwise
mutually agreed in writing between the parties.

15.2 CLOSING OBLIGATIONS

         CMS and Purchaser shall each be required to perform the various
activities described in this Section 15.2 as follows:

         (a)      CMS shall execute, acknowledge and deliver an assignment and
                  such other instruments as may be necessary to convey title to
                  the Subject Property to Purchaser, without warranty or
                  covenant of title (in sufficient counterparts to facilitate
                  recording and governmental consents and filings), in
                  substantially the form of Attachment Q attached hereto and
                  made a part hereof, and shall


                                       46
<PAGE>   52

                  execute and deliver any applicable official federal and state
                  assignment forms in sufficient numbers to meet applicable
                  governmental requirements;

         (b)      The Parties shall execute an agreement in substantially the
                  form of Attachment R, setting forth their agreement as to
                  CMS's limited warranty of title consistent with Section 13.10,
                  above;

         (c)      CMS shall endorse and deliver to Purchaser the Terra Shares;

         (d)      CMS shall execute such other instruments and take such other
                  actions as may be necessary to carry out its obligations under
                  this Agreement;

         (e)      CMS, in conjunction with and after reasonable consultation
                  with Purchaser, shall prepare and present to Purchaser within
                  four (4) business days prior to Closing, a closing statement
                  in accordance with GAAP containing all of the adjustments to
                  the Purchase Price called for by this Agreement (the "Closing
                  Statement"). The final Closing Statement shall fairly
                  represent adjustments proposed in good faith by both Parties;

         (f)      Purchaser shall pay CMS the Purchase Price or Adjusted
                  Purchase Price, as the case may be, as set forth in the
                  Closing Statement, by wire transfer of funds in United States
                  dollars, pursuant to written instructions delivered by CMS;

         (g)      CMS shall endorse and deliver the QRI Stock to Purchaser;

         (h)      CMS shall deliver to Purchaser the Opinion of Counsel
                  referenced in Section 11.5, above;

         (i)      Purchaser shall deliver to CMS the Opinion of Counsel
                  referenced in Section 10.5, above;

         (j)      Purchaser shall execute and acknowledge the assignment, and
                  any and all official federal and state assignment forms, and
                  shall execute such other instruments and take such other
                  actions as may be necessary to carry out its obligations under
                  this Agreement;

         (k)      If Purchaser assumes operatorship of any of the Subject
                  Properties, and to the extent required for the continued
                  operations by Terra of the Terra Property, Purchaser shall
                  execute the necessary documents, such as change of
                  operatorship forms and sundry notices, and shall post all
                  requisite bonds, in sufficient numbers and amounts for filing
                  with government officials. During the period of time between
                  Closing and receipt of all approvals by the State of Michigan
                  Geological Survey Division-Department of Environmental Quality
                  (GSD-DEQ) and others, necessary to complete the change of
                  operatorship, Purchaser agrees to execute any required
                  documentation and to perform and be responsible for any
                  environmental remediation or other action required by the
                  GSD-DEQ to obtain such approval. This provision shall exclude
                  any Environmental, Health and Safety Requirements addressed in
                  accordance with Article XII. Purchaser shall bear the risk of
                  loss, and shall be responsible for all loss, cost, damage and
                  expense which result from operations during the period prior
                  to receipt of all approvals necessary to effectuate a change
                  in operatorship of the Subject Property and responsibility for
                  Terra's continued operation of the Terra


                                       47
<PAGE>   53

                  Property. Purchaser shall defend, indemnify and hold CMS, its
                  parent, affiliate and subsidiary corporations, as well as
                  CMS's and their officers, directors, shareholders, employees
                  and agents, harmless from and against any and all Claims
                  arising out of or in any manner related to operations during
                  the period from the Effective Date to CMS's relinquishment of,
                  and Purchaser's actual assumption of operatorship. Purchaser
                  agrees to take assignments of State of Michigan well permits
                  for those portions of the Subject Property and the Terra
                  Property which are operated by CMS, in the name of Purchaser
                  or its designee, other than Terra;

         (l)      CMS and Purchaser shall execute, acknowledge and deliver any
                  transfer orders or letters in lieu thereof directing all
                  purchasers of production to pay Purchaser all proceeds
                  attributable to production from or allocable to the Subject
                  Property;

         (m)      If CMS is responsible for the disbursement of proceeds of
                  production from or allocable to the Subject Property to third
                  parties after the Transfer Date (or is so responsible on
                  behalf of Terra with respect to the Terra Property), and if
                  Purchaser requires additional time after the Closing to assume
                  this responsibility from CMS, CMS and Purchaser shall enter
                  into a letter agreement in the form of Attachment S to avoid
                  any interruption in the payments to third parties and the
                  filing of any governmental reports as the result of the sale
                  of the Assets. The terms of the letter agreement will provide
                  for CMS to retain responsibility for disbursement of proceeds
                  for a period not to exceed sixty (60) days from the first day
                  of the month following the Closing Date. The letter agreement
                  shall provide for a rate of $50,000.00 per month to be paid to
                  CMS by Purchaser for CMS's services and shall provide that CMS
                  shall not be liable for any errors made. Purchaser shall
                  defend, indemnify and hold CMS harmless from and against any
                  and all Claims, even though caused by CMS's active or passive,
                  sole or concurrent, negligence arising from or relating to the
                  services provided by CMS in making the disbursements per the
                  terms of the letter agreement;

         (n)      CMS shall cause the board of directors and officers of Terra
                  to resign, effective as of April 1, 2000, and shall deliver
                  such documents as may be required to evidence the
                  resignations;

         (o)      At least seven (7) days prior to Closing, the Parties will use
                  their reasonable best efforts to deliver to each other a draft
                  of their proposed press releases to be issued immediately
                  subsequent to Closing. The Parties will use their reasonable
                  best efforts to review and approve, in writing, the other
                  Party's press release prior to Closing; and

         (p)      The Parties shall execute an agreement, in substantially the
                  form of Attachment T, setting forth their agreement as to the
                  terms and conditions of Purchaser's assumption of the
                  Environmental, Health and Safety Requirements with respect to
                  the Facilities identified at Attachment P.

15.3 SUSPENDED ACCOUNTS

                                       48
<PAGE>   54

         CMS shall transfer to Purchaser all suspended royalty, overriding
royalty and other payments out of production relating to the Subject Property
and the Terra Property which are held by CMS, and attributable to the period
prior to the Effective Date. Included in the Assets described in Section 1.1(h)
will be all files and records documenting and directly relating to all such
suspended accounts. Purchaser shall defend, indemnify and hold CMS harmless from
and against any and all Claims relating to those suspended accounts.

15.4 TERMINATION OF GUARANTEES AND OTHER COMMITMENTS

         Subject to applicable laws, as of the Closing Date, CMS shall terminate
or cancel the following: (i) all undertakings, guarantees, comfort letters by
CMS for itself or on behalf of Terra insofar as they relate to the Assets or the
Terra Assets, except for any undertaking with respect to the Assets or the Terra
Assets set forth in a letter agreement dated February 24, 1992 by and between
CMS and Midland Cogeneration Venture, which undertakings shall be a Retained
Liability; (ii) letters of credit, surety bonds and related indemnity agreements
insofar as they relate to the Assets or the Terra Assets; and (iii) all credit
card accounts, lines of credit and open accounts insofar as they relate to the
Assets or the Terra Assets.

                      ARTICLE XVI - CONTINUING OBLIGATIONS

16.1 POST-CLOSING RECONCILIATION

         Not later than one hundred twenty (120) days after Closing, or at such
other date as CMS and Purchaser shall mutually agree upon in writing, CMS shall
issue a "Final Settlement Statement" for the Assets conveyed and assigned to
Purchaser, and for the Terra Assets. The Final Settlement Statement will net
actual revenues against royalties and other lease burdens, operating expenses,
taxes and overhead for the period subsequent to the Effective Date, and such
other adjustments as set forth in this Agreement. The Final Settlement Statement
will include a summary with appropriate supporting documentation. CMS will
accept only written inquiries regarding the Final Settlement Statement. Within
sixty (60) days of its receipt of the Final Settlement Statement, Purchaser
shall either make payment of all amounts due CMS, provide a written request of
payment from CMS of all amounts due Purchaser, or provide a written statement
setting forth those adjustments to which Purchaser objects. Any such written
statement will detail the specific reasons for such objection. In this regard
CMS agrees to provide Purchaser reasonable access to its personnel, files and
records, insofar as they relate to the matters addressed in the Final Settlement
Statement, subject to the limitations expressed in Section 6.11, below. CMS
shall have thirty (30) days from and after its receipt of Purchaser's written
list of objections to rebut same, in writing. If the Parties are unable to
resolve any disagreement with respect to any disputed adjustment, after good
faith negotiations, then the Parties agree to resolve any disputed adjustment
through binding arbitration. Each Party shall select an arbitrator with a joint
interest audit accounting background, and the arbitrators shall select a third
such arbitrator, to arbitrate any such unresolved disputes in accordance with
the rules of the American Arbitration Association, with respect to the Final
Settlement Statement.

16.2 RECEIPTS AND CREDITS

         (a)      All monies, proceeds, receipts, credits and income
                  attributable to hydrocarbon production, and other net income
                  attributable to


                                       49
<PAGE>   55

                  ownership of the Assets and the Terra Assets for all periods
                  of time from and after the Effective Date, regardless of when
                  collected, shall be the sole property and entitlement of the
                  Purchaser. To the extent received by CMS after the Closing,
                  CMS shall fully disclose, account for and promptly transmit
                  same to Purchaser;

         (b)      All monies, proceeds, receipts, credits and income
                  attributable to hydrocarbon production from the Subject
                  Property and the Terra Property for all periods of time prior
                  to the Effective Date, regardless of when collected shall be
                  the sole property and entitlement of CMS. To the extent
                  received by Purchaser after the Closing, Purchaser shall fully
                  disclose, account for and promptly transmit same to CMS;

         (c)      All of CMS's and Terra's proportionate share of operating
                  costs and expenses, for goods delivered and services rendered
                  attributable to the Assets and the Terra Assets for the period
                  of time prior to the Effective Date, regardless of when due or
                  payable, shall be the sole obligation of CMS. CMS shall
                  promptly pay, or if paid by Purchaser, promptly reimburse
                  Purchaser for such operating costs and expenses incurred prior
                  to the Effective Date.

         (d)      All of the proportionate share of operating costs and
                  expenses, for goods delivered and services rendered
                  attributable to the Subject Property and the Terra Property
                  for the period of time from and after the Effective Date,
                  regardless of when due or payable, shall be the sole
                  obligation of Purchaser. Purchaser shall promptly pay, or if
                  paid by CMS, promptly reimburse CMS for such operating costs
                  and expenses incurred by CMS on or after the Effective Date;

         (e)      CMS shall be entitled to retain all overhead charges and any
                  and all other fees, charges or reimbursements related to
                  operations it has collected, billed or which shall be billed
                  or collected at any time, for the operated portions of the
                  Subject Property or the Terra Property relating to the period
                  from and after the Effective Date, to the date on which CMS
                  relinquishes operatorship, or responsibility for Terra's
                  operation of the Subject Property and the Terra Property, even
                  if after the Closing Date. Purchaser shall immediately
                  transfer to CMS any third party overhead charges and other
                  fees, charges or reimbursements related to operations, which
                  are collected by Purchaser, attributable to the operated
                  portions of the Subject Property and the Terra Property, for
                  all periods prior to the date on which CMS relinquishes
                  operatorship;

         (f)      Costs or expenses attributable to non-consent penalties under
                  any contract, law, rule or regulation affecting the Assets or
                  the Terra Assets are deemed transferred with the Assets and
                  are the sole responsibility of the Purchaser.

The obligations of the Parties to disclose, account for, transmit or reimburse
pursuant to subsections (a) - (e), above, shall be limited to the extent that
such items were not previously accounted for as an adjustment to the Purchase
Price.

                                       50
<PAGE>   56

16.3 ASSUMPTION OF OBLIGATIONS AND INDEMNITIES

         If Closing occurs, Purchaser shall, from and after the expiration of
CMS's obligations with respect to any applicable representation or warranty of
CMS, assume and be solely responsible for the obligations and indemnities set
forth in this Section 16.3, which obligations and indemnities shall survive the
Closing.

         (a)      Purchaser hereby agrees and shall agree in the instruments
                  assigning or conveying the Assets, to take the Assets and the
                  Terra Assets subject to, and to assume, perform, pay for, and
                  comply with all of the express or implied duties, liabilities,
                  and obligations, except for the Retained Liabilities, binding
                  upon CMS or Terra that relate to or are attributable to the
                  Assets and the Terra Assets, whether existing before or after
                  the Effective Date, including, but not limited to, all of the
                  following: all of the terms and conditions of all applicable
                  and valid recorded and unrecorded agreements, contracts and
                  instruments relating to the Assets and the Terra Assets
                  (including, but not limited to, those described at Attachment
                  A); all non-consent penalties under any contract, law, rule or
                  regulation affecting the Assets and the Terra Assets; all
                  valid unit, pooling, communitization and operating agreements;
                  all easements and rights-of-way; paying and accounting for and
                  reporting all lease rentals and all royalties, overriding
                  royalties and other oil and gas lease burdens; subject to
                  Article XX, all reassignment rights held by third parties;
                  subject to Article XX all preferential purchase rights held by
                  third parties; and all duties imposed by all valid
                  governmental laws, rules, regulations and orders. Without
                  limiting the generality of the scope of the foregoing, except
                  as to wells which form a part of the Retained Liabilities,
                  Purchaser agrees to and shall assume, perform, pay for and
                  comply with the obligations (if any) of CMS to properly and
                  timely plug and abandon all wells now or hereafter located on
                  or appurtenant to the Subject Property and the Terra Property
                  whether or not such wells are producing, or are capable of
                  producing hydrocarbons as of the Effective Date, to properly
                  and timely remove all buildings, equipment and materials from
                  the Subject Property and the Terra Property upon cessation of
                  use thereof, and to properly and timely restore the surface of
                  the Subject Property and the Terra Property in accordance with
                  all applicable governmental requirements and agreements with
                  third parties.

         (b)      Purchaser, and its heirs, successors, principals, officers,
                  directors and affiliates, shall defend, indemnify and hold
                  CMS, its parent, affiliate and subsidiary corporations, as
                  well as CMS's and their officers, directors, shareholders,
                  employees and agents, harmless from and against any and all
                  Claims and Adverse Consequences of whatsoever kind or nature,
                  that relate to or are attributable to ownership or operation
                  of the Assets and the Terra Assets, except as to the Retained
                  Liabilities, whether the Claims arose before or after the
                  Effective Date, and whether or not the Claims have been
                  specifically disclosed by CMS to Purchaser prior to Closing,
                  including, without limitation in any manner by way of
                  enumeration, Claims and Adverse Consequences relating to the
                  obligations assumed by Purchaser in Section 16.3(a), above,
                  and Claims and Adverse Consequences relating to


                                       51
<PAGE>   57
                  the operations and activities contemplated by Section 16.3(a),
                  above.

         (c)      Purchaser, and its heirs, successors, principals, officers,
                  directors and affiliates, shall defend, indemnify and hold
                  CMS, its parent, affiliate and subsidiary corporations, as
                  well as CMS's and their officers, directors, shareholders,
                  employees and agents, harmless from and against any and all
                  Claims and Adverse Consequences, caused by, relating to or
                  arising out of the following: (i) any condition of or
                  condition on the Assets or the Terra Assets, whether or not
                  the condition existed before the Effective Date, and whether
                  or not caused by CMS or its employees or agents, including,
                  without limitation by way of enumeration, any condition which
                  may be considered to be a nuisance or which in any way
                  adversely affects or threatens to adversely affect natural
                  resources, the environment, or the health and safety of any
                  person or animal; and (ii) Environmental, Health and Safety
                  Requirements applicable to any waste material or Hazardous
                  Substances on or included with the Assets or the Terra Assets,
                  or the presence, disposal, release or threatened release of
                  waste material or Hazardous Substances from the Assets or the
                  Terra Assets into the atmosphere or into or upon land,
                  subsurface strata or any surface or subsurface waters, whether
                  or not attributable to CMS's or Terra's activities or the
                  activities of CMS's officers, employees or agents, or to the
                  activities of third parties (regardless of whether or not CMS
                  or Terra was or is aware of such activities) prior to, during,
                  or after the period of CMS's ownership of the Assets.
                  Purchaser expressly agrees to assume all liability for any
                  condition of or upon the Assets and the Terra Assets,
                  including those which may have been created prior to the
                  Effective Date, and expressly agrees that the preceding
                  indemnification and agreement to hold harmless shall apply to
                  liability for voluntary environmental response actions
                  undertaken pursuant to the federal Comprehensive Environmental
                  Response, Compensation and Liability Act ("CERCLA"), or any
                  other federal, state or local law.

         (d)      Purchaser, its heirs, successors, principals, officers,
                  directors and affiliates shall defend, indemnify and hold CMS,
                  its parent, affiliate and subsidiary corporations, as well as
                  CMS's and their officers, directors, shareholders, employees
                  and agents harmless from and against any and all Claims and
                  Adverse Consequences arising out of a violation or alleged
                  violation of sections 61503A, 61503B or 61503C of Part 615 of
                  the Michigan Natural Resources and Environmental Protection
                  Act, which occur or are alleged to have occurred from or after
                  the Effective Date.

         (e)      The parties agree that, to the extent allowed by applicable
                  law, the indemnity provisions of this Section 16.3 shall apply
                  regardless of whether CMS was wholly or partially, actively or
                  passively, negligent or otherwise at fault, and whether or not
                  the Claims are based on a theory of negligence, negligence per
                  se, strict liability, willful misconduct, products liability,
                  premises liability, liability based on statute, or other
                  theory of liability as to the applicable indemnitee or others,
                  and regardless of by whom the Claims are made or brought,
                  including, without limitation, CMS's, Terra's or Purchaser's
                  employees, agents or representatives, private citizens,
                  persons or organizations, or any representatives of federal,
                  state or local government.

                                       52
<PAGE>   58

         (f)      The Parties agree that, except with regard to the Retained
                  Liabilities, and upon the expiration of CMS's obligation with
                  respect to any applicable representation or warranty of CMS,
                  to the extent the provisions of any instrument conveying or
                  assigning the Assets to Purchaser conflict with or appear to
                  limit the provisions of this Section 16.3, the provisions of
                  this Section 16.3 shall control.

16.4 RECORDING

         After Closing, Purchaser, at its sole cost and expense shall promptly
record the assignment(s) and all other instruments of conveyance, in the
appropriate offices of the states and/or counties in which the Subject Property
is located. After Closing, Purchaser shall also forward to the applicable
governmental agencies for approval any applicable federal or state assignment
form(s). When available, Purchaser shall thereafter promptly forward to CMS
copies of any recorded or filed instruments which are returned to Purchaser.
After Closing, Purchaser shall forward to the applicable governmental agencies
for approval of any forms, requisite bonds and permit transfers, relating to the
change of operatorship to Purchaser which have not been previously filed, and
Purchaser shall be responsible for all costs associated therewith, if any. After
Closing, Purchaser shall promptly make all necessary governmental notifications
(if any) which have not been previously made concerning the transfer of all or
any part of the Assets.

16.5 STATE OF MICHIGAN OIL AND GAS LEASES

         Purchaser shall take all actions and file all documents which may be
required to cause the records of the State of Michigan to reflect the transfer
of all State of Michigan oil and gas leases comprising a portion of the Subject
Property, from CMS to Purchaser, and for CMS to be relieved of all
responsibility and liability thereunder. Such actions shall include, but are not
limited to: (i) request of change in lease status with the appropriate
department of the State of Michigan, (ii) the written acceptance and assumption
of responsibility of the lessee under all such leases and post the appropriate
lease performance bond, and (iii) obtain the written approval of the State of
Michigan, and provide same to CMS. Purchaser, and its heirs, successor,
principals, officers, directors and affiliates, shall defend, indemnify and hold
CMS, its parent, affiliate and subsidiary corporations, as well as CMS's and
their officers, directors, shareholders, employees and agents harmless from and
against any and all Claims relating to ownership of an interest in any State of
Michigan oil and gas leases comprising a portion of the Subject Property or the
Terra Property, arising from and after the Effective Date. As to the State of
Michigan oil and gas leases held by Terra, the existing lease performance bond
shall be canceled, and Purchaser's lease performance bond substituted therefore;
or Purchaser shall otherwise assume responsibility for Terra's bond, in a manner
acceptable to CMS, as soon as is reasonably possible. Purchaser, and its heirs,
successor, principals, officers, directors and affiliates, shall defend,
indemnify and hold CMS, its parent, affiliate and subsidiary corporations, as
well as CMS's and their officers, directors, shareholders, employees and agents
harmless from and against any and all Claims relating to CMS's responsibility
with respect to events relating to the foregoing which occur after the Effective
Date.

16.6 FURTHER ASSURANCES

                                       53
<PAGE>   59

         After Closing, CMS and Purchaser agree to take such further actions and
execute, acknowledge and deliver all such further documents that are reasonably
necessary or useful in carrying out the purposes of this Agreement or of any
document delivered pursuant to this Agreement.

16.7 RECORDS

         After Closing, CMS will provide the originals, or in CMS's sole
discretion, copies of its files and all files relating to the Terra Assets to
Purchaser pursuant to Section 1.1(h) hereof. If CMS retains any original files,
it shall provide a copy of all such files to Purchaser at CMS's expense, and
shall further provide Purchaser and explanation of the reasons for CMS's
retention of the original file. CMS may retain, at CMS's expense, copies of its
original files so transferred. CMS will return any retained original files upon
its determination that it no longer is required to retain such originals.
Purchaser shall reimburse CMS for all reasonable shipping costs.

16.8 ACCESS TO RECORDS

         Purchaser, its heirs, successors and assigns, shall, at Purchaser's
expense, preserve and retain all files and records relating to the Assets for
the period required by all applicable laws and regulations or seven (7) years,
whichever is longer. Purchaser agrees to provide CMS and its duly designated
representatives with access to and the right to copy and inspect any of the
files and records relating to the Assets, at all reasonable time, upon
reasonable advance written notice.

16.9 LITIGATION SUPPORT

         In the event and for so long as any Party actively is contesting or
defending against any action, suit, proceeding, hearing, investigation, charge,
complaint, claim, or demand in connection with (i) any transaction contemplated
under this Agreement or (ii) any fact, situation, circumstance, status,
condition, activity, practice, plan, occurrence, event, incident, action,
failure to act, or transaction on or prior to the Closing Date involving any of
CMS, Terra and its Subsidiaries or the Assets and the Terra Assets, the other
Party shall cooperate with it and its counsel in the defense or contest, make
available their personnel, and provide such testimony and access to their books
and records as shall be necessary in connection with the defense or contest, all
at the sole cost and expense of the contesting or defending Party (unless the
contesting or defending Party is entitled to indemnification therefor under the
provisions of this Agreement).

16.10 CMS EMPLOYEES

         Purchaser agrees (which agreement shall survive the termination of this
Agreement), to refrain from employing, either directly or indirectly, whether as
a salaried or contract employee, or otherwise, or from utilizing in any manner
the services, knowledge or expertise of any person employed by CMS other than
those based out of CMS's Traverse City, Michigan office as of January 14, 2000,
for a period of one (1) year from and after the Closing Date.

16.11 TRANSITION

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<PAGE>   60

         CMS will not take any action that is designed or intended to have the
effect of discouraging any lessor, licensor, customer, supplier, or other
business associate of any of Terra and its Subsidiaries from maintaining the
same business relationships with Terra and its Subsidiaries after the Closing as
it maintained with Terra and its Subsidiaries prior to the Closing.

         After Closing, CMS will permit representatives of Purchaser reasonable
access, during normal business days and hours, and in a manner so as not to
interfere with the normal business operations of CMS, to personnel and financial
books and records of CMS (including, without limitation, tax records, and to the
extent prepared, net operating statements for the years 1997, 1998 and 1999),
insofar only as they relate to the Assets, and are required for Purchaser's
preparation of financial statements required by the Securities Exchange
Commission. CMS shall not be required to provide access to any such books,
records or information which it deems, in its sole discretion to be proprietary
or confidential, or which it may not divulge without violating agreements with
third parties. Purchaser for itself and its representatives, agrees to keep all
information obtained pursuant to its review of such books and records, strictly
confidential in accordance with the provisions of Section 22.10, below, except
for such Securities Exchange Commission filing purposes. Purchaser agrees to and
shall defend, indemnify and hold CMS, and its parent, affiliate and subsidiary
corporations, as well as CMS's and their officers, directors, employees and
agents, harmless from and against any and all Claims and Adverse Consequences
arising out of or in any manner related to Purchaser's access to and use of such
materials, including, without limitation by reason of damage or injury to any
person or property caused thereby.

16.12 PLAN B

         (a)      With respect to Northern Michigan Exploration Company
                  (predecessor to CMS) Employee Well Participation Plans A and
                  B, dated April 1, 1980, and amended as of April 1, 1985 and
                  April 1, 1990, Purchaser hereby agrees that:

                  (i)      from and after the Effective Date, the Subject
                           Property which are affected thereby, are and shall
                           remain subject to "Employee Participation Interests",
                           as defined in Plan B;

                  (ii)     from and after the Closing Date, Purchaser will
                           discharge all obligations in connection with such
                           Employee Participation Interests under Plan B,
                           including distribution of revenue attributable to
                           production from the Subject Property, from and after
                           the Effective Date; and

                  (iii)    from and after the Closing Date, Purchaser will cause
                           any subsequent transferees of the Subject Property to
                           agree in writing to comply with the provisions of
                           Plan B.

         (b)      Within ninety (90) days after the Closing Date, Purchaser
                  agrees to make good faith offers to purchase the Employee
                  Participation Interests from all owners thereof, for a price
                  substantially equivalent to the price for the applicable
                  portion of the Subject Property in accordance with Attachment
                  H, taking into account the size and nature of the Plan B
                  interests, and commensurate with the applicable terms of this
                  Agreement.

                           ARTICLE XVII - TERMINATION

17.1 RIGHT OF TERMINATION

         This Agreement and the transactions contemplated hereby may be
terminated in the following instances:

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<PAGE>   61

         (a)      If the conditions set forth at Article X are not satisfied by
                  Purchaser or waived by CMS as of the Closing Date, CMS may
                  terminate this Agreement;

         (b)      If the conditions set forth at Sections 11.2 through 11.5,
                  inclusive are not satisfied by CMS or waived by Purchaser as
                  of the Closing Date, Purchaser may terminate this Agreement;

         (c)      At any time by mutual written agreement of CMS and Purchaser,
                  and in accordance with any other express provision of this
                  Agreement, CMS and Purchaser may mutually terminate this
                  Agreement;

         (d)      If there has been a material breach of any of the
                  representations and warranties of CMS which are specified in
                  Section 11.1, above, Purchaser may terminate this Agreement
                  unless CMS agrees to indemnify Purchaser with regard to such
                  breach as provided in this Section 17.1(d). Within four (4)
                  business days after any such breach becomes known, discovered
                  or disclosed to Purchaser (whether by CMS pursuant to Section
                  8.6 or otherwise consistent with Section 9.6), Purchaser shall
                  provide to CMS written notice of Purchaser's intent to
                  terminate this Agreement due to such breach. CMS shall within
                  two (2) business days of its receipt of any such notice from
                  Purchaser, provide Purchaser with written notice of CMS's
                  decision of whether or not CMS will indemnify Purchaser from
                  and against all Adverse Consequences arising from such breach,
                  without limitation. In the event CMS elects to indemnify
                  Purchaser, such indemnity shall terminate upon the cure or
                  satisfaction of the matter, event or occurrence giving rise to
                  such breach. In the event CMS elects not to indemnify
                  Purchaser as to the Adverse Consequence arising from such
                  breach, then Purchaser shall within two (2) business days of
                  its receipt of written notice of CMS's election, either agree
                  in writing to consummate the transaction contemplated by this
                  Agreement, or terminate this Agreement by written notice to
                  CMS. Failure of Purchaser to respond within two (2) business
                  days of receipt of CMS's election shall be deemed a waiver of
                  Purchaser's right to terminate this Agreement on account of
                  such breach. If Purchaser waives, or is deemed to have waived
                  such breach, the Parties shall consummate the transaction
                  contemplated herein. Subject to the provisions of Sections
                  18.1 and 18.2, no waiver by Purchaser of its right to
                  terminate this Agreement under this Section 17.1(d) shall
                  preclude Purchaser from any post-Closing remedy provided in
                  this Agreement to Purchaser on account of any breach of the
                  representations and warranties of CMS that are specified in
                  Section 11.1. Regardless of when any such breach becomes
                  known, discovered or disclosed to Purchaser, CMS may prevent
                  Purchaser from asserting the breach as a basis for termination
                  of this Agreement by agreeing to indemnify Purchaser as
                  provided above.

         (e)      By either Party if the Closing shall not have occurred on or
                  before March 31, 2000, unless the failure to close results
                  from a material breach or default of this Agreement by the
                  Party seeking termination.

17.2 LIABILITIES UPON TERMINATION OR FAILURE TO CLOSE

         In the event this Agreement is terminated by either Party for any
reason set forth in Section 17.1, then neither Party shall be liable to the


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<PAGE>   62

other for any indirect, incidental or consequential damages, except as provided
in Section 17.3 as to Purchaser's interference with CMS's rights in the Assets
or the Terra Assets after termination.

17.3 DEPOSIT

         (a)      If this Agreement is terminated by CMS pursuant to Sections
                  10.1, 10.2, or 10.6, not having been satisfied by Purchaser or
                  not having been waived by CMS; or Purchaser's failure to
                  close, as provided in Section 17.1(e), CMS shall have the
                  right, in addition to all other rights set forth herein, to
                  retain the Deposit as partial liquidated damages, and to seek
                  any additional amount of actual damages which CMS may suffer
                  in excess of the amount of the Deposit. If this Agreement is
                  terminated for any reason, CMS shall immediately enjoy all
                  rights of ownership of the Assets and the Terra Assets and to
                  sell, transfer, encumber or otherwise dispose of the Assets
                  and the Terra Assets to any party without any restriction
                  under this Agreement, and Purchaser shall be liable for all
                  damages, including, but not limited to, direct, indirect,
                  incidental and consequential damages, if Purchaser attempts to
                  interfere in any way with CMS's assertion or enjoyment of
                  CMS's rights in the Assets and the Terra Assets after
                  termination. If this Agreement is terminated for any other
                  reason, CMS shall return the Deposit to Purchaser, without
                  interest.

         (b)      In the event the transaction contemplated by this Agreement
                  does not close, and CMS is entitled to retain the Deposit, as
                  provided in Section 17.3(a), above, then and in that event,
                  CMS shall be entitled to retain the cash component of the
                  Deposit. In this event CMS shall also have a put option with
                  respect to twenty-five percent (25%) of the QRI Stock on each
                  of June 30, 2000, September 30, 2000, December 31, 2000 and
                  March 30, 2001 at $4 1/8 per share, $4 1/4 per share, $4 3/8
                  per share and $4 1/2 per share, respectively. The Parties
                  hereby agree that within fifteen (15) days of delivery of
                  written notice of CMS's election to exercise a put option, CMS
                  will deliver the shares of QRI Stock which are the subject of
                  the put option to Purchaser, and Purchaser will concurrently
                  pay CMS an amount equal to the number of shares of QRI Stock
                  which are put, multiplied by the applicable put option share
                  price. Purchaser shall have a call option on not less than
                  twenty-five percent (25%) of the QRI Stock, at any time and
                  from time to time, at a price that is the sum of $4 per share
                  plus interest at the rate of twelve and one-half percent
                  (12.5%) per annum computed from the Closing Date to the date
                  the call option is exercised. CMS agrees to immediately
                  transfer the affected QRI Stock if Purchaser timely and
                  properly exercises one or more of its call options.

17.4 EFFECT OF TERMINATION

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<PAGE>   63

         If any Party terminates this Agreement pursuant to Section 17.1, above,
then except as provided in Section 17.3., above, all rights and obligations of
the Parties hereunder shall terminate without any liability of any Party to any
other Party (except for any liability of any Party then in breach); provided,
however, that the confidentiality provisions contained in Section 22.10, below,
shall survive any such termination.

             ARTICLE XVIII - REMEDIES FOR BREACHES OF THIS AGREEMENT

18.1 SURVIVAL OF REPRESENTATIONS AND WARRANTIES

         The representations and warranties of CMS which are contained in
Sections 4.1, 4.2, 4.3, 4.4, 4.16, 6.1, 6.3, 6.4, 6.6, 6.9, 6.11 and 6.13,
above, will expire at, and shall not survive the Closing. In the event that the
transaction contemplated by this Agreement does not proceed to closing, and CMS
is entitled to retain the Deposit in accordance with Section 17.3, above, then
the representation and warranty contained in Section 4.16, above, will survive
until all of the QRI Stock is put or called as provided in Section 17.3(b),
above. The representations and warranties of CMS set forth in Sections 4.13 and
6.16, above, will survive the Closing for a period of four (4) months (until
July 31, 2000), and shall thereafter expire and be of no further force and
effect in accordance with the indemnity provisions of Section 13.10, above, and
subject to the limitations imposed in Sections 13.3(b) and 13.5, above. The
representations and warranties of CMS which are set forth in Sections 4.5, 4.6,
4.7, 4.11, 4.12, 4.14, 4.15, 6.2, 6.5, 6.7, 6.8, 6.14, 6.17, 6.18 and 6.19,
above shall survive the Closing for a period of one (1) year and shall
thereafter expire and be of no further force and effect. The representations and
warranties of CMS set forth in Sections 4.8, 4.9, 4.10, 6.10, 6.12 and 6.15,
above, shall survive the Closing for a period of two (2) years and shall
thereafter expire and be of no further force and effect.

18.2 INDEMNIFICATION PROVISIONS FOR BENEFIT OF THE PURCHASER

         (a)      In the event CMS breaches any of its representations,
                  warranties, and covenants contained herein, and, if there is
                  an applicable survival period pursuant to Section 18.1, above,
                  provided that Purchaser makes a written claim for
                  indemnification against CMS pursuant to Section 22.7, below
                  within such survival period, then CMS agrees to indemnify
                  Purchaser from and against any Claims and Adverse Consequences
                  Purchaser shall suffer through and after the date of the claim
                  for indemnification (but excluding any Claims and Adverse
                  Consequences Purchaser shall suffer as to any matter, event or
                  occurrence which Purchaser does not timely and properly raise
                  prior to the end of any applicable survival period) caused
                  proximately by the breach. Purchaser shall not be entitled to
                  any indemnification for those representations and warranties
                  contained in Sections 4.5 through 4.12, inclusive [except
                  4.11(b)], Sections 4.14 and 4.15, Sections 6.2, 6.7, 6.8
                  [except 6.8(w)], 6.10, 6.12, 6.14, 6.15, 6.17 and 6.18 (the
                  "Limited Representations"), unless the aggregate amount of the
                  loss or damage to Purchaser resulting from a breach or
                  breaches exceeds $300,000.00, and anything contained herein to
                  the contrary notwithstanding, the total aggregate
                  indemnification of Purchaser by CMS as a result of any and all
                  such breaches of the Limited Representations shall be limited
                  to the sum of $5,000,000.00. In no event shall CMS indemnify
                  Purchaser for any Claims relating to the first $300,000.00 of
                  claims alleged by Purchaser relating to the Limited
                  Representations, whether or not the cumulative net


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<PAGE>   64

                  amount of all such Claims exceeds that sum. With respect to
                  any such breach of the representations and warranties
                  contained in Sections 4.11(b) and 6.8(w), above, the total
                  aggregate indemnification of Purchaser by CMS shall be limited
                  to the amount of the tax credit valuation for each of the
                  wells comprising the Subject Property and the Terra Property.

         (b)      CMS also agrees to indemnify Purchaser from and against any
                  Adverse Consequences Purchaser shall suffer as a result of any
                  breach of the representations and warranties of CMS contained
                  in Sections 6.5 and 6.19, above, provided, however, that
                  Purchaser shall not be entitled to any indemnification under
                  this Section 18.2(b) unless the aggregate amount of the loss
                  or damage to Purchaser exceeds $1,000,000.00, but in no event
                  shall the total aggregate indemnification of Purchaser by CMS
                  under this Section 18.2(b) exceed $20,000,000.00.

         (c)      CMS also agrees to indemnify Purchaser from and against any
                  Adverse Consequences Purchaser shall suffer as a result of any
                  action, suit, proceeding, hearing or investigation relating
                  directly to the Assets or Terra Assets, the basis for which is
                  an event which occurred prior to the Effective Date, and as to
                  which Purchaser has asserted a written claim pursuant to
                  Section 22.7, below, within two (2) years of the Closing Date.
                  The obligations of CMS under this Section 18.2(c) shall be
                  subject to the same limitations expressed in Section 18.2(a),
                  above, with regard to the Limited Representations.

18.3 INDEMNIFICATION PROVISIONS FOR BENEFIT OF CMS

         In the event Purchaser breaches any of its representations, warranties,
and covenants contained herein, provided that CMS makes a written claim for
indemnification against Purchaser pursuant to Section 22.7, below, within such
survival period, then Purchaser agrees to indemnify CMS from and against the
entirety of any Claims and Adverse Consequences CMS shall suffer through and
after the date of the claim for indemnification (but excluding any Claims and
Adverse Consequences CMS shall suffer after the end of any applicable survival
period) caused proximately by the breach.

18.4 MATTERS INVOLVING THIRD PARTIES

         (a)      If any third party shall notify any Party (the "Indemnified
                  Party") with respect to any matter (a "Third Party Claim")
                  which notification may give rise to a claim for
                  indemnification against any other Party (the "Indemnifying
                  Party") under this Article XVIII, then the Indemnified Party
                  shall promptly and in any event within five (5) business days
                  after receiving notice of the Third Party Claim notify the
                  Indemnifying Party thereof in writing. Notwithstanding the
                  foregoing, the provisions of this Section 18.4 shall apply to
                  any notice delivered later than five (5) business days
                  subsequent to receipt of any Third Party Claim, so long as the
                  Indemnifying Party is not materially prejudiced by the fact
                  that such notice is delivered after five (5) business days
                  from receipt of the Third Party Claim.

         (b)      The Indemnifying Party will have the right at any time to
                  assume and thereafter conduct the defense of the Third Party
                  Claim with counsel of its choice reasonably satisfactory to
                  the Indemnified Party; provided, however, that the
                  Indemnifying Party will not


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<PAGE>   65

                  consent to the entry of any judgment or enter into any
                  settlement with respect to the Third Party Claim without the
                  prior written consent of the Indemnified Party (not to be
                  withheld unreasonably) unless the judgment or proposed
                  settlement involves only the payment of money damages and does
                  not impose an injunction or other equitable relief upon the
                  Indemnified Party.

         (c)      Unless and until the Indemnifying Party assumes the defense of
                  the Third Party Claim as provided in Section 18.4(b), above,
                  however, the Indemnified Party may defend against the Third
                  Party Claim in any manner it reasonably may deem appropriate.

         (d)      In no event will the Indemnified Party consent to the entry of
                  any judgment or enter into any settlement with respect to the
                  Third Party Claim without the prior written consent of the
                  Indemnifying Parties (not to be withheld unreasonably).

18.5 DETERMINATION OF ADVERSE CONSEQUENCES

         The Parties shall make appropriate adjustments for tax benefits and
insurance coverage and take into account the time cost of money (using the prime
interest rate quoted in the Wall Street Journal as the discount rate) in
determining Adverse Consequences for purposes of this Article XVIII. All
indemnification payments under this Article XVIII shall be deemed adjustments to
the Purchase Price.

18.6 EXCLUSIVE REMEDY

         The Parties acknowledge and agree that except as otherwise specifically
provided in this Agreement, the foregoing indemnification provisions in this
Article XVIII shall be the exclusive remedy of Purchaser with respect to CMS,
Terra, its Subsidiaries, and the transaction contemplated by this Agreement.

                               ARTICLE XIX - TAXES

19.1 LIABILITY FOR TAXES

         (a)      Except for taxes which are specifically to be reimbursed by
                  Purchaser pursuant to Sections 19.5 and 19.9, below, CMS shall
                  be liable for and indemnify Purchaser for all Taxes imposed on
                  Purchaser and Terra (or for which Purchaser may otherwise be
                  liable) arising from the Assets, the Terra Assets or
                  activities of Terra and its Subsidiaries for any taxable year
                  or period of Terra or its Subsidiaries that ends as of the end
                  of the day on the Closing Date and, with respect to any
                  taxable year or period beginning before and ending after the
                  Closing Date, the portion of such taxable year ending at the
                  end of the day on the Closing Date.

         (b)      Purchaser and Terra shall be liable for and indemnify CMS for
                  the Taxes imposed on the Assets, the Terra Assets or
                  activities of Terra and its Subsidiaries for any taxable year
                  or period that begins after the Closing Date and, with respect
                  to any taxable year or period beginning before and ending
                  after the Closing Date, the portion of such taxable year or
                  period beginning after the Closing Date.

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<PAGE>   66

         (c)      For purposes of Sections 19.1(a) and 19.1(b), above, whenever
                  it is necessary to determine the liability of the Parties for
                  Taxes for a portion of a taxable year or period that begins
                  before and ends after the Closing Date, the determination of
                  the Taxes for the portion of the year or period ending before,
                  and the portion of the year or period beginning on, and
                  continuing after the Closing Date shall be determined by
                  assuming a taxable year or period which ended at the close of
                  the Closing Date, except that exemptions, allowances or
                  deductions that are calculated on an annual basis, such as the
                  deduction for depreciation, shall be apportioned on a daily
                  basis.

         (d)      After the execution of this Agreement, Purchaser or its
                  designee shall have the right to inspect, at all reasonable
                  times, and upon forty-eight (48) hours prior written request
                  delivered to CMS, the following: (i) all Income Tax Returns of
                  Terra and its Subsidiaries requested by Purchaser; (ii) any
                  other Tax Returns of Terra and its Subsidiaries requested by
                  Purchaser, as may be relevant to Terra and its Subsidiaries,
                  and which relate to the Terra Assets and operation of the
                  Terra Property; and (iii) any work papers or other supporting
                  data requested by Purchaser relating to Tax Returns made
                  available pursuant to (i) or (ii), or relating to Tax Returns
                  referred to in (i) or (ii) not yet filed, to the extent copies
                  of such Tax Returns, work papers or other data are in
                  existence and in the possession of CMS at the time of such
                  request.

         (e)      CMS shall be entitled to receive any refund or credit of Taxes
                  (and interest thereon) attributable to a carryback of losses,
                  credits or other similar items from a taxable year or period
                  that ends on or before the Closing Date, and Purchaser shall
                  be entitled to such items attributable to a taxable year or
                  period that ends after the Closing Date.

         (f)      CMS shall be entitled to any Tax refunds due Terra or its
                  Subsidiaries for and attributable to all periods prior to the
                  Closing Date, and if received by Purchaser, Purchaser shall
                  immediately deliver all such refunds to CMS.

19.2 TAX RETURNS

         CMS shall file when due (after taking into account all extensions
properly obtained) all Tax Returns that are required to be filed by or with
respect to Terra and its Subsidiaries for the taxable year ending on or before
the Closing Date and shall remit or cause to be remitted any Taxes shown to be
due on such Tax Returns; and Purchaser shall file when due (after taking into
account all extensions properly obtained) all Tax Returns that are required to
be filed by Terra and its Subsidiaries for taxable years beginning after the
Closing Date, and shall remit or cause to be remitted any Taxes due in respect
of such Tax Returns. CMS agrees to file those Tax Returns for periods on or
before the end of the day of Closing Date which CMS is required to file under
applicable rules relating to when the Assets are actually transferred. All Tax
Returns which Purchaser, Terra or CMS are required to file in accordance with
this Section 19.2 shall be prepared and filed in a manner consistent with past
practice and, on such Tax Returns no position shall be taken or method adopted
that is inconsistent with positions taken or methods used in preparing and
filing similar Tax Returns in prior periods except for changes required by law
or changes in facts, or as the Parties otherwise agree.

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<PAGE>   67

19.3 CONTEST PROVISIONS

         Purchaser shall notify CMS in writing upon receipt of notice of any
pending or threatened federal, state or local Tax audit or assessment (including
any revenue agent report or notice of proposed adjustment) which may materially
affect the Tax liabilities of Terra or its Subsidiaries for which CMS would be
required to indemnify Purchaser pursuant to Section 19.1(a), above.

         CMS shall have the sole right to represent the interests of Terra and
its Subsidiaries in any Tax audit or administrative or court proceeding relating
to taxable periods ending on or before the Closing Date, and to employ counsel
of their choice at their expense, provided that Purchaser (and their tax
counsel) may, at their own expense, be present at and participate in any such
audit or proceeding. Notwithstanding the foregoing, CMS shall not be entitled to
settle, either administratively or after the commencement of litigation, any
claim for Taxes which would adversely affect the liability for Taxes of
Purchaser for any period after the Closing Date to any extent (including, but
not limited to, the imposition of Income Tax deficiencies, the reduction of
asset basis or cost adjustments, the lengthening of any amortization or
depreciation periods, the denial of amortization, depreciation or depletion
deductions) without the prior written consent of the Purchaser. Such consent
shall not be necessary to the extent that CMS has indemnified Purchaser against
the effects of any such settlement.

         A representative of CMS (and their tax counsel) may, at its own
expense, be present at and participate in any audit or proceeding relating to
the matters covered by this Article XIX. Purchaser shall not settle any dispute
with respect to such matters without the consent of CMS, except that Purchaser
may settle any such dispute without the consent of CMS if it agrees to relieve
CMS of their indemnification obligation hereunder with respect to such
transaction.

19.4 ASSISTANCE AND COOPERATION

         After the Effective Date, each of CMS and the Purchaser shall:

         (a)      Agree to timely sign and deliver such certificates or forms as
                  may be necessary or appropriate to establish an exemption from
                  (or otherwise reduce) or make a report with respect to any
                  Taxes including those described in Section 19.10, below.

         (b)      Assist (and cause their respective affiliates to assist) the
                  other Party in preparing any Tax Returns which such other
                  Party is responsible for preparing and filing in accordance
                  with Section 19.2, above.

         (c)      Cooperate fully in preparing for any audits of, or disputes
                  with taxing authorities regarding, any Tax Returns of Terra
                  and its Subsidiaries.

         (d)      Make available to the other Party and to any taxing authority
                  as reasonably requested, all information, records, and
                  documents relating to Taxes of Terra and its Subsidiaries.

         (e)      Provide timely notice to the other Party in writing of any
                  pending or threatened Tax audits or assessments of Terra and
                  its


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                  Subsidiaries for taxable periods for which the other may have
                  a liability under this Article XIX.

         (f)      Furnish the other Party with copies of all correspondence
                  received from any taxing authority in connection with any Tax
                  audit or information request with respect to any such taxable
                  period.

         CMS and Purchaser shall provide each other with reasonable access to
all relevant documents, data and other information which may be required for the
purpose of preparing Tax Returns and responding to any audit by any taxing
jurisdiction. CMS and Purchaser shall cooperate with all reasonable requests of
the other made in connection with contesting the imposition of Taxes. Neither
CMS nor Purchaser shall be required at any time to disclose to the other any
Income Tax Returns or other confidential Tax information.

19.5 ADJUSTMENT TO PURCHASE PRICE FOR TAXES

         Purchaser shall reimburse CMS for any Taxes (without taking into
account any section 29 tax credits) payable by CMS with respect to the Assets or
attributable to the operation of Terra for the Interim Period. Any payment by
CMS or Purchaser under this Article XIX shall be considered an adjustment to the
Purchase Price paid in connection with the transaction contemplated by this
Agreement, and to the extent that it cannot be so characterized for Tax
purposes, shall be made on an After-Tax Basis. For purposes of this Agreement,
the term After-Tax Basis means, with respect to any amount which is to be paid
hereunder on an "After-Tax Basis", an amount which, after subtraction of the
amount of all federal, state and local Taxes payable by the recipient thereof as
a result of the receipt or accrual of such payment, and after taking into
account (i) the increase in federal, state and local Taxes (including estimated
Taxes) payable by such recipient for all affected taxable years as a result of
the event or occurrence giving rise to such payment, and (ii) the reduction in
federal, state and local Taxes (including estimated Taxes) payable by the
recipient for all applicable taxable years, including the present value (using
the applicable federal rate as the discount rate) of all reasonably anticipated
future tax reduction for taxable years ending on or after the end of the taxable
year in which such payment is made, shall be sufficient as of the date of
payment to compensate the recipient for such event or occurrence giving rise to
such payment.

 19.6 TREATMENT OF THE TERRA SHARES

         The Parties hereby acknowledge and agree that transfer of the Terra
Shares shall not be treated or considered to be an asset purchased for purposes
of Code section 338(h)(10).

19.7 CMS TAX ALLOCATION AGREEMENT

         The participation of Terra and its Subsidiaries in the CMS Energy
Corporation tax allocation agreement shall only relate to periods prior to the
Effective Date.

19.8 BOOKS AND RECORDS

         At Closing, or as soon thereafter as is reasonably practical, CMS shall
deliver to Purchaser all books and records relating to Terra and its
Subsidiaries, except that CMS shall retain originals or copies of all books


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and records necessary or convenient for CMS to prepare the Tax Returns it is
required to file pursuant to Section 19.2, above.

19.9 SALES TAXES

         The Purchase Price is net of any sales taxes or other transfer taxes in
connection with the sale of the Assets. Purchaser shall be liable for any sales
tax or other transfer tax, as well as any applicable conveyance, transfer and
recording fees, and real estate transfer stamps or taxes imposed on the transfer
of the Assets. Purchaser shall indemnify and hold CMS harmless from liability
for payment of any such Taxes, including any interest or penalties assessed
thereon.

19.10 OTHER TAXES

         All severance, production, conservation, excise, windfall profit,
single business and other Taxes, other than Income Taxes and those Taxes covered
by Section 19.9, above, or fees relating to production of oil, gas and
condensate attributable to the Assets assessed prior to the Effective Date shall
be paid by CMS, except to the extent taken into account under Section 3.3,
above. All such Taxes relating to production of oil, gas and condensate
attributable to the Terra Assets assessed on or after the Effective Date shall
be paid by Purchaser, regardless of the method or basis used for calculating the
Tax.

              ARTICLE XX - EXERCISE OF PREFERENTIAL PURCHASE RIGHTS

         CMS agrees to use commercially reasonable best efforts to identify any
and all parties holding a preferential right to purchase, right to reacquire,
consent to transfer and any other contractual right to acquire or consent to the
transfer of the Assets or the Terra Assets, as contemplated by this Agreement.
CMS will provide the required notice to the holders of all such rights which it
has identified and shall provide a copy of all such notifications to Purchaser
and any and all responses thereto. CMS will thereafter provide to Purchaser a
list which identifies the contracts and agreements giving rise to the notices
which CMS has provided pursuant to this Article XX. If during the Interim Period
any holder of a preferential purchase right or right of reassignment affecting
any portion of the Subject Property or the Terra Property notifies CMS or
Purchaser prior to Closing that the holder intends to exercise the holder's
rights and purchase or reacquire a portion of the Subject Property or the Terra
Property to which a preferential purchase right or right of reassignment
applies, those interests shall be excluded from the Assets to be conveyed to
Purchaser, and the Purchase Price shall be reduced in accordance with the
provision of Section 3.3, above. The value of the downward adjustment to the
Purchase Price shall be a proportionate decrease in the portion of the Purchase
Price allocated to the applicable interest in an oil and gas lease affected by
the preferential purchase right or right of reassignment. If the holder of a
preferential purchase right or right of reassignment fails to consummate the
purchase or reacquisition of all or a portion of the Subject Property or the
Terra Property affected by the right, CMS shall so notify Purchaser, and within
fifteen (15) days after Purchaser's receipt of notice from CMS, CMS shall sell
to Purchaser, and Purchaser shall purchase from CMS the applicable interest for
a price equal to the portion of the Purchase Price allocated to the applicable
interest and upon the other terms of this Agreement. All interests comprising
the Subject Property or the Terra Property for which a preferential purchase
right or right of reassignment have not been asserted prior to Closing shall be
sold and conveyed to Purchaser at Closing pursuant to the provisions of this
Agreement. If prior to Closing CMS is unable to timely and properly identify and
notify the holders of any preferential purchase rights, rights to reacquire or
consent rights, CMS shall so notify


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<PAGE>   70

Purchaser, and CMS will, with reasonable diligence proceed to identify and
notice the holders of such rights. If one or more of the holders of any
preferential purchase rights or rights to reacquire notifies CMS subsequent to
the Closing that it intends to assert its preferential purchase right, CMS shall
give notice thereof to Purchaser. Purchaser shall satisfy all preferential
purchase right and right to reacquire obligations of CMS to the holders thereof.
CMS shall indemnify and hold Purchaser harmless from and against any and all
Claims in connection with any preferential purchase rights, rights to reacquire
or consent rights which are asserted subsequent to Closing, except as to the
value assigned to the affected portion of the Subject Property or the Terra
Property, pursuant to Attachment H. Purchaser agrees to convey any Assets or
Terra Asset to the holder of any preferential purchase right. right to reacquire
or similar contractual rights, which are properly exercised subsequent to
Closing. Purchase shall be entitled to receive, and CMS hereby assigns to
Purchaser all of CMS's rights to all proceeds received from holders of
preferential purchase rights and rights to reacquire which are properly
exercised subsequent to Closing.

             ARTICLE XXI - INDEPENDENT INVESTIGATION AND DISCLAIMER

21.1 DISCLAIMER AS TO WARRANTIES

         The Parties agree that the disclaimer of warranties contained in this
Section 21.1. and in the conveyance instruments to be delivered pursuant to this
Agreement are conspicuous disclaimers for the purposes of any applicable law,
rule or order. PURCHASER ACKNOWLEDGES THAT IN MAKING THE DECISION TO ENTER INTO
THIS AGREEMENT AND CONSUMMATE THE TRANSACTIONS CONTEMPLATED HEREBY, PURCHASER
HAS RELIED SOLELY ON THE BASIS OF ITS OWN EXPERTISE AND INDEPENDENT
INVESTIGATION OF THE ASSETS AND THE TERRA ASSETS, EXCEPT AS OTHERWISE
SPECIFICALLY PROVIDED IN THIS AGREEMENT. PURCHASER ACKNOWLEDGES THAT EXCEPT FOR,
AND TO THE EXTENT OF THE REPRESENTATIONS AND WARRANTIES EXPRESSLY SET FORTH IN
ARTICLES IV AND VI, ABOVE, CMS HAS NOT MADE, AND CMS HEREBY EXPRESSLY DISCLAIMS
AND NEGATES, ANY REPRESENTATION OR WARRANTY, EXPRESS OR IMPLIED, AT COMMON LAW,
BY STATUTE, OR OTHERWISE RELATING TO (I) TITLE TO OR THE CONDITION OF THE ASSETS
(INCLUDING WITHOUT LIMITATION, ANY IMPLIED OR EXPRESS WARRANTY OF
MERCHANTABILITY, OF FITNESS FOR A PARTICULAR PURPOSE, OR OF CONFORMITY TO MODELS
OR SAMPLES OF MATERIALS AS TO ANY PERSONAL PROPERTY OR FIXTURES TO BE CONVEYED)
AND (II) ANY INFORMATION, DATA OR OTHER MATERIALS (WRITTEN OR ORAL) FURNISHED TO
PURCHASER BY OR ON BEHALF OF CMS (INCLUDING, WITHOUT LIMITATION, THE EXISTENCE
OR EXTENT OF OIL, GAS OR OTHER MINERAL RESERVES, THE RECOVERABILITY OF OR THE
COST OF RECOVERING ANY SUCH RESERVES, THE VALUE OF SUCH RESERVES, ANY PRODUCT
PRICING ASSUMPTIONS, PRESENT OR PAST PRODUCTION RATES, COMPLIANCE WITH LEASE
TERMS, THE CONDITION OF ANY WELL, AND THE ABILITY TO SELL OIL OR GAS PRODUCTION
AFTER CLOSING). PURCHASER COVENANTS AND REPRESENTS THAT, SUBJECT TO THE
OBLIGATIONS OF CMS WITH RESPECT TO THE RETAINED LIABILITIES, PURCHASER HAS
INSPECTED OR BEFORE CLOSING WILL INSPECT THE ASSETS AND THE TERRA ASSETS, AND
ACCEPTS THE SAME "AS IS", "WHERE IS" AND "WITH ALL FAULTS".

21.2 DISCLAIMER AS TO YEAR 2000 COMPLIANCE

         Certain of the Assets and the Terra Assets may rely on computer
systems, including embedded chips, to enhance their function. Many of those
systems may have recorded years in a two-digit format. Such computer systems, if
not replaced or modified so as to become "Year 2000 Compliant", may be unable to
properly recognize dates arising in the year 2000 and later. As used herein,
"computer systems" includes, but is not limited to, computer hardware and
software (including macrocode, firmware, embedded chips,


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<PAGE>   71

application programs, files, databases, and third-party software embedded
therein), and electronic components and systems. As used herein, the term "Year
2000 Compliant" means that the computer systems will provide accurate and
uninterrupted information and calculations unaffected by dates (including the
dates of 9/9/99, 1/1/00 and dates arising in the calendar year 2000 and later,
including leap years), and that the performance and functionality of the
computer systems will not be adversely affected by said dates.

         With regard to this issue, to the Knowledge of CMS, it has encountered
no material problems or difficulties since the Effective Date. CMS expressly
disclaims and negates any and all other representation or warranty, express or
implied, at common law, by statute, or otherwise, as to whether the Assets or
the Terra Assets and/or such systems are, or are not, "Year 2000 Compliant".
Purchaser agrees to purchase the Assets in their "As Is, Where Is, and With Any
and All Faults and Defects" condition, as related to such Assets, the Terra
Assets and such systems being "Year 2000 Compliant", and covenants and agrees
that it will indemnify and hold CMS harmless from and against any and all
Claims, and all actual, indirect, incidental, and consequential damages, if any,
brought or suffered by it or any third party based upon any failure of the
Assets, the Terra Assets or such systems to be "Year 2000 Compliant".

                          ARTICLE XXII - MISCELLANEOUS

22.1 LIKE-KIND EXCHANGE

         CMS shall have the option, at or before Closing, to structure the
Closing of this transaction in such a manner so as to qualify, in whole or in
part, as part of a like-kind exchange pursuant to Section 1031 of the Code.
Purchaser will cooperate with CMS to facilitate a like-kind exchange, including
a three corner or multi-party exchange. In the event CMS desires such an
exchange, CMS shall timely notify Purchaser of its intent within seven (7) days
prior to Closing and CMS shall be responsible for arrangement of the structure
for the exchange, compliance with time limits on like-kind exchanges, the
preparation of appropriate documents to complete the transaction, and all
additional costs directly related thereto.

22.2 GOVERNING LAW

         This Agreement, the validity of the various conveyances made hereunder
affecting title to real property, the indemnities herein and the other documents
delivered pursuant hereto and the legal relations among the Parties shall be
governed by and construed in accordance with the laws of the State of Michigan.

22.3 ENTIRE AGREEMENT

         This Agreement and the Attachments attached hereto constitute the
entire agreement between CMS and Purchaser with respect to the Assets and the
Terra Assets, and supersedes all prior agreements, understandings, negotiations
and discussions, whether oral or written, between CMS and Purchaser. No
supplement, amendment, alteration, modification, waiver or termination of this
Agreement shall be binding unless executed in writing by both CMS and Purchaser.

22.4 AMENDMENTS AND WAIVERS

         No amendment of any provision of this Agreement shall be valid unless


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the same shall be in writing and signed by Purchaser and CMS. No waiver by any
Party of any default, misrepresentation, or breach of warranty or covenant
hereunder, whether intentional or not, shall be deemed to extend to any prior or
subsequent default, misrepresentation, or breach of warranty or covenant
hereunder or affect in any way any rights arising by virtue of any prior or
subsequent such occurrence.

22.5 CAPTIONS

         The captions in this Agreement are for convenience only and shall not
be considered a part of or affect the construction or interpretation of any
provision of this Agreement.

22.6 ASSIGNMENT

         Purchaser shall not assign this Agreement or any of its rights or
obligations pursuant to this Agreement without CMS's prior written consent. CMS
hereby acknowledges and agrees that in the event Purchaser defaults under the
terms of its purchase money finance obligations with respect to the transaction
contemplated by this Agreement, then upon written notice to CMS, Purchaser's
rights and obligations under this Agreement may be assigned to Purchaser's
primary lending institution. No such assignment shall be effective unless and
until the assignee agrees in writing to accept and assume the rights, duties and
obligations of Purchaser hereunder. Any such assignment shall be at no cost or
expense to CMS, and shall not be deemed to extend any of the time periods set
forth herein. Unless such written consent of CMS so specifies, subsequent to any
assignment of Purchaser's interest hereunder including the assignment provided
for above, Purchaser shall not be released from any responsibility or liability
for the obligations, covenants, representations, warranties or indemnities of
Purchaser under this Agreement. Any assignment made without CMS's consent shall
be void. This Agreement shall be binding upon and inure to the benefit of CMS
and Purchaser and their respective successors, heirs and assigns. CMS may,
without Purchaser's prior approval, assign its interest under this Agreement to
a qualified intermediary in order to pursue a like-kind exchange.

22.7 NOTICES

         Any notice provided or permitted to be given under this Agreement shall
be in writing, and may be served by personal delivery, telefacsimile with
confirmation of receipt or by depositing the notice in the United States mail,
addressed to the Party to be notified, postage prepaid, and registered or
certified with a return receipt requested. Notice may also be given by sending
the written notification by courier service. Notice deposited in the mail in the
manner described by this Section 22.7 shall be deemed to have been given and
received on the date of the delivery as shown on the return receipt. Notice
served in any other manner shall be deemed to have been given and received only
if and when actually received by the addressee. For purposes of notice, the
addresses of the parties shall be as follows:

         CMS's Mailing Address:

               CMS Oil and Gas Company
               1021 Main Street, Suite 2800
               Houston, Texas 77002
               Attention:  Michael J. Killelea, Chief Counsel
               Phone:      713-230-7221
               Fax:        713-651-0622

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<PAGE>   73

         Purchaser's Mailing Address:

               Quicksilver Resources Inc.
               1619 Pennsylvania Avenue
               Forth Worth, Texas 76104
               Attention:  Houston Kauffman, Vice-President
               Phone:      817-332-9133
               Fax:        817-877-8959

         Each Party shall have the right, upon giving ten (10) days prior
written notice to the other to change its address for purposes of notice.

22.8 EXPENSES

         Except as specifically provided otherwise in this Agreement, CMS and
Purchaser shall each be solely responsible for all expenses incurred by it in
connection with this transaction, including, without limitation, fees and
expenses of their own counsel and accountants.

22.9 SEVERABILITY

         If any term or provision (or portion thereof) of this Agreement is held
invalid, illegal or incapable of being enforced under any rule of law or
regulation, all remaining conditions and provisions of this Agreement shall
survive and remain in full force and effect to conform to the Parties' intent,
so long as the economic or legal substance is not affected in a materially
adverse manner with respect to either Party.

22.10 CONFIDENTIALITY, PUBLICITY AND RETENTION OF DATA

         (a)      Until completion of the Closing, and in the event the
                  transaction contemplated by this Agreement is not consummated
                  for any reason, whatsoever, except as required by law and with
                  prior notice to CMS, Purchaser and its agents and
                  representatives will hold in strict confidence all
                  Confidential Information obtained from CMS, any other Person,
                  or derived from information provided by CMS, or as a result of
                  Section 5.6, Section 8.5, Section 12.2, or Section 13.1,
                  above, whether before or after the execution of this
                  Agreement, except any data or information which (i) at the
                  time of the disclosure to Purchaser by CMS is in the public
                  domain; (ii) after disclosure to Purchaser by CMS becomes part
                  of the public domain by publication or otherwise, except by
                  breach of this commitment by Purchaser; (iii) Purchaser can
                  establish by competent proof it was rightfully in its
                  possession at the time of disclosure to Purchaser by CMS; (iv)
                  Purchaser rightfully receives from any Person free of any
                  obligation of confidence; or (v) is developed independently by
                  Purchaser, provided the Person or Persons developing the
                  information shall not have had reference to data or
                  information obtained from CMS in connection with the
                  transaction contemplated by this Agreement. If this Agreement
                  is terminated for any reason and as to any portion of the
                  Assets or the Terra Assets not assigned or conveyed to
                  Purchaser at Closing, Purchaser shall return to CMS all
                  Confidential Information obtained from CMS related to all or
                  the portion of the Assets or the Terra Assets not conveyed.
                  Purchaser shall not utilize or permit utilization of
                  Confidential Information to compete with CMS or its co-working
                  interest owners in the Assets and the Terra Assets. The terms
                  of this Section 22.10 shall survive any termination of this
                  Agreement.

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<PAGE>   74

         (b)      CMS and Purchaser shall use their reasonable best efforts to
                  provide one another with drafts of the press releases to be
                  issued immediately subject to Closing. The Parties will use
                  their reasonable best efforts to approve such press releases
                  prior to Closing. Except as required by applicable law or the
                  applicable rules or regulations of any governmental body or
                  stock exchange, neither Party shall issue any publicity or
                  other release without the prior written consent of the other
                  Party, which consent shall not be unreasonably withheld.

22.11 USE OF CMS'S NAME

         No later than ten (10) days after the Closing, Purchaser shall use its
reasonable best efforts to remove or cause to be removed the names and marks
used by CMS and all variations and derivatives and logos from the Assets or the
Terra Assets, if CMS has not already done so. Purchaser shall not make any use
whatsoever of CMS's names, marks and logos after Closing. CMS shall have the
right to enter any premises and remove all signs and logos containing CMS's name
at Purchaser's expense should Purchaser fail to do so in a timely manner.

22.12 CONDITIONS

         The inclusion in this Agreement of conditions to either Party's
obligation to close shall not, in and of itself, constitute a covenant of the
other Party to satisfy the conditions to either Party's obligation to close.

22.13 NO THIRD-PARTY BENEFICIARIES

         This Agreement shall not confer any rights or remedies upon any Person
other than the Parties and their respective successors and permitted assigns.

22.14 SUCCESSION AND ASSIGNMENT

         This Agreement shall be binding upon and inure to the benefit of the
Parties named herein and their respective successors and permitted assigns.

22.15 CONSTRUCTION

         The Parties have participated jointly in the negotiation and drafting
of this Agreement. In the event an ambiguity or question of intent or
interpretation arises, this Agreement shall be construed as if drafted jointly
by the Parties and no presumption or burden of proof shall arise favoring or
disfavoring any Party by virtue of the authorship of any of the provisions of
this Agreement. Any reference to any federal, state or local statute or law
shall be deemed also to refer to all rules and regulations promulgated
thereunder, unless the context requires otherwise.

22.16 ATTACHMENTS

         A reference to an Attachment throughout this Agreement shall mean and
be construed as referring to an Attachment attached to this Agreement, and all
Attachments shall be deemed to have been fully incorporated into and made a part
of this Agreement.

22.17 COUNTERPARTS

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<PAGE>   75

         This Agreement maybe executed in one or more counterparts, each of
which shall be deemed an original, but all of which together shall constitute
one and the same instrument.

22.18 EXECUTION DEADLINE

         This Agreement shall be open for acceptance up to, but not after, 5:00
P.M. Central Standard Time on March 6, 2000, and if not accepted by the
execution and return of one (1) original to CMS by such time, shall be null and
void at CMS's option. Acceptance within the time provided shall constitute a
contract of purchase and sale binding upon the Parties hereto and their
respective successors and assigns.


CMS OIL AND GAS COMPANY                     QUICKSILVER RESOURCES INC.



By: /s/ William H. Stephens III       By: /s/ Houston Kauffman
   ------------------------------        ------------------------------
   Name:  William H. Stephens III        Name:  Houston Kauffman
        -------------------------             -------------------------
   Title: Executive Vice                 Title: Vice President
          President, General                  -------------------------
          Counsel and Secretary
         ------------------------
   Tax I.D. No.:                              Tax I.D. No.:
                -----------------                          ---------------

                                 ACKNOWLEDGMENT

STATE OF                            )
                                    ) ss
COUNTY OF                           )

On this       day of                    , 2000 before me, the undersigned, a
Notary Public, in and for the County and State aforesaid, personally appeared
                    , known to be the identical person who executed the
foregoing instrument as                         of CMS Oil and Gas Company, and
acknowledged to me that he executed the same as his free and voluntary act and
deed and as the free and voluntary act and deed of such corporation, for the
uses and purposes therein set forth.


                                    -------------------------------------------
                                    Notary Public

                                    My Commission Expires:
                                                          -------------





                                 ACKNOWLEDGMENT

STATE OF                            )
                                    ) ss
COUNTY OF                           )

On this       day of                    , 2000 before me, the undersigned, a
Notary Public, in and for the County and State aforesaid, personally appeared
                    , known to be the identical person who executed the


                                       70
<PAGE>   76

foregoing instrument as                    of Quicksilver Resources Inc. and
acknowledged to me that he executed the same as his free and voluntary act and
deed and as the free and voluntary act and deed of such corporation, for the
uses and purposes therein set forth.


                                    -------------------------------------------
                                    Notary Public

                                    My Commission Expires:
                                                          -------------





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