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                                                                  EXHIBIT 10.140

                           PURCHASE AND SALE AGREEMENT

     This Purchase and Sale Agreement (this "Agreement") dated as of the 6th day
of August, 2000, is between and among CASTLE EXPLORATION COMPANY, INC., a
corporation organized and existing under the laws of Pennsylvania ("CECI"),
PARKS & LUTTRELL ENERGY PARTNERS, L.P., a limited partnership organized and
existing under the laws of the State of Texas ("P&L LP") and PARKS & LUTTRELL
ENERGY, INC., a corporation organized and existing under the laws of the State
of Texas ("P&L Inc.").

     CECI, P&L LP and P&L Inc. are referred to herein individually as a "Party"
and collectively as the "Parties". For purposes of Article 10 and Article 11 of
this Agreement , "Seller" shall mean CECI with respect to the Britt Ranch
Properties and shall mean P&L Inc. with respect to the Frisco City Properties
and "Buyer" shall mean P&L LP with respect to the Britt Ranch Properties and
shall mean CECI with respect to the Frisco City Properties.

     In consideration of the mutual promises contained herein, the benefits to
be derived by each Party hereunder and other good and valuable consideration,
the receipt and sufficiency of which are hereby acknowledged, CECI, P&L LP and
P&L Inc. agree as follows:

                                    ARTICLE 1
                                PURCHASE AND SALE

     1.1 Purchase and Sale. Subject to the terms and conditions of this
Agreement,:

     (a) CECI agrees to sell, assign and convey and P&L LP agrees to purchase
and pay for all of CECI's right, title and interest in and to the Britt Ranch
Properties as defined on Exhibit A hereto; and

     (b) P&L Inc. agrees to sell, assign and convey and CECI agrees to purchase
and pay for all of P&L Inc.'s right, title and interest in and to the Frisco
City Properties as defined on Exhibit B hereto.

     (c) The Britt Ranch Properties and the Frisco City Properties may be
collectively referred to herein as the "Properties" or individually as a
"Property."

     1.2 Britt Ranch Properties. The Britt Ranch Properties shall include:

     (a) The oil, gas and mineral leases described on Exhibit "A" attached
hereto

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(collectively, the "Britt Ranch Leases"), including, without limitation, working
interests, overriding royalty interests, royalty interests and any other
interests of a similar nature affecting the lands covered by the Leases
(collectively, the "Britt Ranch Lands").

     (b) The oil and gas wells described on Exhibit "A" (individually, a "Britt
Ranch Well," and collectively, the "Britt Ranch Wells"), together with all oil,
natural gas, casinghead gas, drip gasoline, natural gas liquids, condensate and
other minerals produced from such Britt Ranch Wells.

     (c) All unitization, communitization, pooling, agreements, working interest
units created by operating agreements, partnership agreements and orders
covering the Britt Ranch Leases and Lands, or any portion thereof, and the units
and pooled or communitized areas created thereby (collectively, the "Britt Ranch
Units").

     (d) The tangible personal property, tools, machinery, materials, pipelines,
plants, gathering systems, equipment, platforms and facilities, fixtures and
improvements, which are incident or attributable to or underlie the Britt Ranch
Leases, Lands, Wells or Units with the production, transportation, treatment,
sale or disposal of hydrocarbons or water produced therefrom or attributable
thereto, (collectively, the "Britt Ranch Equipment").

     (e) The licenses, permits, contracts, agreements and other instruments
owned by CECI (other than bonds posted by CECI) which concern and relate to any
of the Britt Ranch Leases, Lands, Wells, Units and/or Equipment, INSOFAR AND
ONLY INSOFAR as same concern or relate to the Britt Ranch Leases, Lands, Wells,
Units and/or Equipment, or the operation thereof; including, without limitation,
oil, gas and condensate purchase and sale contracts; permits; rights-of-way;
easements; licenses; servitudes; estates; surface leases; farmin and farmout
agreements; division orders and transfer orders; bottomhole agreements; dry hole
agreements; area-of-mutual interest agreements; salt water disposal agreements;
acreage contribution agreements; operating agreements; balancing agreements and
unit agreements; pooling agreements; pooling orders; communitization agreements;
processing, gathering, compression and transportation agreements; facilities or
equipment leases relating thereto or used or held for use in connection with the
ownership or operation thereof or with the production, treatment, sale or
disposal of hydrocarbons; and all other contracts and agreements related to the
Britt Ranch Leases, Lands, Wells and/or Equipment.

     (f) Subject to Section 1.6 below, originals or copies of all computer tapes
and discs, files, records, information or data relating to the Britt Ranch
Properties in the possession of CECI, including, without limitation, title
records (including abstracts of title, title opinions, certificate of title and
title curative documents), accounting records and files, contracts,
correspondence, production records, electric logs, core data, pressure data,
decline curves, graphical production curves, drilling reports, well completion
reports, drill stem test charts and reports, regulatory reports, and all related
materials, INSOFAR AND ONLY INSOFAR as the foregoing items constitute materials
that may be lawfully conveyed to P&L LP (i.e., the materials are not subject to
a proprietary agreement precluding their transfer to P&L LP), and, to the extent
transferable, all other contract rights, intangible rights (excluding CECI's
trademarks and service

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marks), inchoate rights, choses in action, rights under warranties made by prior
owners, manufacturers, vendors or other third parties, and rights accruing under
applicable statutes of limitation or prescription, attributable to the Britt
Ranch Properties.

     (g) All payments, and all rights to receive payments, with respect to the
ownership of the production of hydrocarbons from or the conduct of operations on
the Britt Ranch Properties accruing after the Effective Time.

     1.3 Frisco City Properties. The Frisco City Properties shall include:

     (a) The oil, gas and mineral leases described on Exhibit "B" attached
hereto (collectively, the "Frisco City Leases"), including, without limitation,
working interests, overriding royalty interests, royalty interests and any other
interests of a similar nature affecting the lands covered by the Leases
(collectively, the "Frisco City Lands").

     (b) The oil and gas wells described on Exhibit "B" (individually, a "Frisco
City Well," and collectively, the "Frisco City Wells"), together with all oil,
natural gas, casinghead gas, drip gasoline, natural gas liquids, condensate and
other minerals produced from such Frisco City Wells.

     (c) All unitization, communitization, pooling, agreements, working interest
units created by operating agreements, partnership agreements and orders
covering the Frisco City Leases and Lands, or any portion thereof, and the units
and pooled or communitized areas created thereby (collectively, the "Frisco City
Units").

     (d) The tangible personal property, tools, machinery, materials, pipelines,
plants, gathering systems, equipment, platforms and facilities, fixtures and
improvements, which are incident or attributable to or underlie the Frisco City
Leases, Lands, Wells or Units with the production, transportation, treatment,
sale or disposal of hydrocarbons or water produced therefrom or attributable
thereto, (collectively, the "Frisco City Equipment").

     (e) The licenses, permits, contracts, agreements and other instruments
owned by P&L Inc. (other than bonds posted by P&L Inc.) which concern and relate
to any of the Frisco City Leases, Lands, Wells, Units and/or Equipment, INSOFAR
AND ONLY INSOFAR as same concern or relate to the Frisco City Leases, Lands,
Wells, Units and/or Equipment, or the operation thereof; including, without
limitation, oil, gas and condensate purchase and sale contracts; permits;
rights-of-way; easements; licenses; servitudes; estates; surface leases; farmin
and farmout agreements; division orders and transfer orders; bottomhole
agreements; dry hole agreements; area-of-mutual interest agreements; salt water
disposal agreements; acreage contribution agreements; operating agreements;
balancing agreements and unit agreements; pooling agreements; pooling orders;
communitization agreements; processing, gathering, compression and
transportation agreements; facilities or equipment leases relating thereto or
used or held for use in connection with the ownership or operation thereof or
with the production, treatment, sale or disposal of hydrocarbons; and all other
contracts and agreements related to the Frisco City Leases, Lands, Wells and/or
Equipment.

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     (f) Subject to Section 1.6 below, originals or copies of all computer tapes
and discs, files, records, information or data relating to the Frisco City
Properties in the possession of P&L Inc., including, without limitation, title
records (including abstracts of title, title opinions, certificate of title and
title curative documents), accounting records and files, contracts,
correspondence, production records, electric logs, core data, pressure data,
decline curves, graphical production curves, drilling reports, well completion
reports, drill stem test charts and reports, regulatory reports, and all related
materials, INSOFAR AND ONLY INSOFAR as the foregoing items constitute materials
that may be lawfully conveyed to CECI (i.e., the materials are not subject to a
proprietary agreement precluding their transfer to CECI), and, to the extent
transferable, all other contract rights, intangible rights (excluding P&L Inc.'s
trademarks and service marks), inchoate rights, choses in action, rights under
warranties made by prior owners, manufacturers, vendors or other third parties,
and rights accruing under applicable statutes of limitation or prescription,
attributable to the Frisco City Properties.

     (g) All payments, and all rights to receive payments, with respect to the
ownership of the production of hydrocarbons from or the conduct of operations on
the Frisco City Properties accruing after the Effective Time.

     1.4 Reserved Interests. Notwithstanding any provision of this Agreement to
the contrary, each of CECI and P&L Inc. reserve and retain (i) their respective
corporate, financial, tax and legal records and its other business records; (ii)
cash, bank accounts, letters of credit, travel letter accounts and prepaid
insurance; (iii) the management information systems and other intellectual
property used by them in the management and administration of their respective
businesses; (iv) all claims that each of CECI and P&L Inc. may have under any
policy of insurance, indemnity or bond maintained by CECI and P&L Inc. other
than claims relating to property damage or casualty loss affecting the Britt
Ranch Properties and Frisco City Properties, respectively, occurring between the
Effective Time and Closing (which claims shall be included in the Britt Ranch
Properties and Frisco City Properties, respectively); (v) all accounts
receivable, trade credits or notes receivable accrued before the Effective Time;
(vi) any files or records that each of CECI or P&L Inc. are contractually or
otherwise obligated not to disclose to third parties; (vii) all claims and
causes of action arising from acts, omissions or events, or damage or
destruction of property occurring prior to the Effective Time; (viii)
engineering studies or reserve reports relating to the Britt Ranch Properties
and Frisco City Properties, respectively; (ix) all interests and rights not
included in the definition of the Britt Ranch Properties and Frisco City
Properties, respectively (the "Reserved Interests").

     1.5 Effective Time. The purchase and sale of the Britt Ranch Properties and
the Frisco City Properties shall be contemporaneously effective as of July 1,
2000, at 7:00 a.m., central standard time (herein called the "Effective Time").

     1.6 Ownership of the Properties.

     (a) Subject to Section 13.1 and the other provisions of this Agreement,
should Closing

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occur, CECI shall be entitled to all of the rights of ownership (including,
without limitation, the right to all production, proceeds of production and
other proceeds), and shall be subject to the duties and obligations of such
ownership attributable to the Britt Ranch Properties for the period of time
prior to the Effective Time and P&L LP shall be entitled to all of the rights of
ownership (including, without limitation, the right to all production, proceeds
of production and other proceeds) and shall be subject to the duties and
obligation of such ownership attributable to the Britt Ranch Properties for the
period of time from and after the Effective Time. All expenses and costs,
including, without limitation, all ad valorem, property, production, severance,
and similar taxes and assessments based upon or measured by the ownership of the
Britt Ranch Properties , the production of hydrocarbons, or the receipt of
proceeds therefrom) attributable to the Britt Ranch Properties , shall be: (i)
allocated to CECI if incurred or accruing with respect to operations conducted
prior to the Effective Time; or (ii) allocated to P&L LP if incurred or accruing
with respect to operations conducted after the Effective Time. All hydrocarbons
in storage facilities above or upstream from the pipeline connection to each
storage facility, or downstream of delivery point sales meters on gas pipelines,
as of the Effective Time, shall belong to CECI. All of the hydrocarbons placed
in such storage facilities or upstream of the aforesaid meters on pipelines
after the Effective Time shall belong to P&L LP and shall become a part of the
Britt Ranch Properties. In order to accomplish the foregoing allocation of
production, the parties shall rely upon the severance tax or other records
maintained by the operator of the relevant Britt Ranch Property, unless such
records are demonstrated to be inaccurate.

     (b) Subject to Section 13.1 and the other provisions of this Agreement,
should Closing occur, P&L Inc. shall be entitled to all of the rights of
ownership (including, without limitation, the right to all production, proceeds
of production and other proceeds), and shall be subject to the duties and
obligations of such ownership attributable to the Frisco City Properties for the
period of time prior to the Effective Time and CECI shall be entitled to all of
the rights of ownership (including, without limitation, the right to all
production, proceeds of production and other proceeds) and shall be subject to
the duties and obligation of such ownership attributable to the Frisco City
Properties for the period of time from and after the Effective Time. All
expenses and costs, including, without limitation, all ad valorem, property,
production, severance, and similar taxes and assessments based upon or measured
by the ownership of the Frisco City Properties , the production of hydrocarbons,
or the receipt of proceeds therefrom) attributable to the Frisco City Properties
, shall be: (i) allocated to P&L Inc. if incurred or accruing with respect to
operations conducted prior to the Effective Time; or (ii) allocated to CECI if
incurred or accruing with respect to operations conducted after the Effective
Time. All hydrocarbons in storage facilities above or upstream from the pipeline
connection to each storage facility, or downstream of delivery point sales
meters on gas pipelines, as of the Effective Time, shall belong to P&L Inc.. All
of the hydrocarbons placed in such storage facilities or upstream of the
aforesaid meters on pipelines after the Effective Time shall belong to CECI and
shall become a part of the Frisco City Properties. In order to accomplish the
foregoing allocation of production, the parties shall rely upon the severance
tax or other records maintained by the operator of the relevant Frisco City
Property, unless such records are demonstrated to be inaccurate.

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     1.7 Risk of Loss. P&L LP shall assume all risk of loss with respect to the
Britt Ranch Properties from and after the Effective Time to Closing. CECI shall
assume all risk of loss with respect to the Frisco City Properties from and
after the Effective Time to Closing.

                                    ARTICLE 2
                                 PURCHASE PRICE

     2.1 Purchase Price. The purchase price for Britt Ranch Properties shall be
Two Hundred Sixty Thousand Dollars ($260,000) paid by cashiers check, wire
transfer or other immediately available funds (the "Britt Ranch Payment"). The
purchase price for the Frisco City Properties shall be One Hundred Ten Thousand
Dollars ($110,000) paid by cashiers check, wire transfer or other immediately
available funds (the "Frisco City Payment"). The Britt Ranch Payment and the
Frisco City Payment shall be adjusted as set forth respectively in Sections 2.2
and 2.3 below.


     2.2 Adjustments to Britt Ranch Payment. In the Final Settlement Statement,
the Britt Ranch Payment shall be adjusted as follows and the resulting amount
shall be referred to herein as the "Adjusted Britt Ranch Payment":

     (a) The Britt Ranch Payment shall be adjusted upward by the following:

          i.   The amount of all actual operating or capital expenditures or
               prepaid expenses attributable to the Britt Ranch Properties
               incurred by or on behalf of CECI in connection with the operation
               of the Britt Ranch Properties and which are, according to
               generally accepted accounting principles, attributable to the
               period of time between the Effective Time and August 31, 2000.
               Such expenditures and expenses shall include, without limitation,
               royalties, rentals and other charges; ad valorem, property,
               excise, and any other taxes based upon or measured by the
               ownership of the Britt Ranch Properties, the production of
               hydrocarbons or the receipt of proceeds therefrom; and expenses
               payable to a third person under applicable joint operating
               agreements, including, without limitation, overhead charges at
               existing COPAS rates and royalty disbursement fees payable to
               operator, or similar payments to third party operators, or, in
               the absence of any joint operating agreement, those items
               customarily billed under such an agreement.

          ii.  The value, less taxes (other than taxes on net income), of all
               hydrocarbons in storage facilities above or upstream from the
               pipeline connection in each storage facility, or downstream of
               delivery point, sales meters on gas pipelines, as of the
               Effective Time, at the prevailing market value at the time of
               sale in the area, adjusted for grade and gravity.

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          iii. Any other amounts agreed upon by CECI and P&L LP.

     (b) The Britt Ranch Payment shall be adjusted downward by the following:

          i.   Reductions due to Title Failures as provided in Sections 10.7.

          ii.  For uncured Title Defects and Contested Defects pursuant to
               Section 10.8

          iii. Reductions due to Environmental Defects as provided in Section
               11.3.

          iv.  The gross proceeds earned by CECI, net of applicable severance
               and production taxes and compression and transportation charges,
               and derived from the sale of hydrocarbons attributable to the
               Britt Ranch Properties to the extent owned by P&L LP between the
               Effective Time and August 31, 2000, pursuant to the provisions of
               Section 1.6(a) above.

          v.   Reductions due to receipt by CECI of denials to consent and of
               exercises of preferential rights as provided in Section 10.11.

          vi.  Any other amounts agreed upon by CECI and P&L LP.

     (c) CECI shall pay all capital expenditures and expenses accruing prior to
August 31, 2000, and shall collect and receive all proceeds accruing prior to
August 31, 2000. CECI shall be responsible for accounting for all revenues
earned and expenses incurred through to August 31, 2000.

     2.3 Adjustments to Frisco City Payment. In the Final Settlement Statement,
the Frisco City Payment shall be adjusted as follows and the resulting amount
shall be referred to herein as the "Adjusted Frisco City Payment":

     (a) The Frisco City Payment shall be adjusted upward by the following:

          i.   The amount of all actual operating or capital expenditures or
               prepaid expenses attributable to the Frisco City Properties
               incurred by or on behalf of P&L Inc. in connection with the
               operation of the Frisco City Properties and which are, according
               to generally accepted accounting principles, attributable to the
               period of time between the Effective Time and August 31, 2000.
               Such expenditures and expenses shall include, without limitation,
               royalties, rentals and other charges; ad valorem, property,
               excise, and any other taxes based upon or

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               measured by the ownership of the Frisco City Properties, the
               production of hydrocarbons or the receipt of proceeds therefrom;
               and expenses payable to a third person under applicable joint
               operating agreements, including, without limitation, overhead
               charges at COPAS rates per month and royalty disbursement fees
               payable to operator, or similar payments to third party
               operators, or, in the absence of any joint operating agreement,
               those items customarily billed under such an agreement.

          ii.  The value, less taxes (other than taxes on net income), of all
               hydrocarbons in storage facilities above or upstream from the
               pipeline connection in each storage facility, or downstream of
               delivery point, sales meters on gas pipelines, as of the
               Effective Time, at the prevailing market value at the time of
               sale in the area, adjusted for grade and gravity.

          iii. Any other amounts agreed upon by P&L Inc. and CECI.

     (b) The Frisco City Payment shall be adjusted downward by the following:

          i.   Reductions due to Title Failures as provided in Sections 10.7.

          ii.  For uncured Title Defects and Contested Defects pursuant to
               Section 10.8

          iii. Reductions due to Environmental Defects as provided in Section
               11.3.

          iv.  The gross proceeds earned by P&L Inc., net of applicable
               severance and production taxes and compression and transportation
               charges, and derived from the sale of hydrocarbons attributable
               to the Frisco City Properties to the extent owned by CECI between
               the Effective Time and August 31, 2000, pursuant to the
               provisions of Section 1.6(b) above.

          v.   Reductions due to receipt by P&L Inc. of denials to consent and
               of exercises of preferential rights as provided in Section 10.11.

          vi.  Any other amounts agreed upon by P&L Inc. and CECI.

     (c) P&L Inc. shall pay all capital expenditures and expenses accruing prior
to August 31, 2000, and shall collect and receive all proceeds accruing prior to
August 31, 2000. P&L Inc. shall be responsible for accounting for all revenues
earned and expenses incurred through to August 31, 2000.

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     2.4 Purchase Price Allocation. The Britt Ranch Payment shall be allocated
among the Britt Ranch Properties as set forth in Exhibit "C" attached hereto and
the Frisco City Payment shall be allocated among the Frisco City Properties as
set forth in Exhibit "D" attached hereto (the "Allocated Values").

                                    ARTICLE 3
                         REPRESENTATIONS AND WARRANTIES

 3.1 Representations and Warranties of CECI. CECI represents and warrants to P&L
LP the following:

     (a) CECI is a corporation duly organized, validly existing and in good
standing under the laws of the State of Pennsylvania. CECI is duly qualified to
carry on its business in Texas.

     (b) CECI has all requisite power and authority to carry on its business as
presently conducted and to enter into this Agreement, to purchase the Frisco
City Properties on the terms described in this Agreement and to perform its
obligations hereunder.

     (c) The execution, delivery and performance of this Agreement and the
transactions contemplated herein have been duly and validly authorized by CECI.

     (d) This Agreement has been duly executed and delivered on behalf of CECI,
and all documents and instruments required hereunder to be executed and
delivered by CECI at or prior to Closing shall have been duly executed and
delivered. This Agreement does, and such documents and instruments shall,
constitute legal, valid and binding obligations of CECI enforceable in
accordance with their terms.

     (e) CECI has incurred no liability, contingent or otherwise, for broker's
or finder's fees or commissions relating to the transactions contemplated by
this Agreement for which P&L LP shall have any responsibility whatsoever.

     (f) There are no outstanding authorizations for expenditures ("AFEs") that
(i) require the drilling of wells or other material development operations in
order to earn or to continue to hold all or any portion of the Britt Ranch
Properties, or (ii) obligate CECI to make payments of any amounts in connection
with drilling of wells or other material capital expenditures affecting the
Britt Ranch Properties.

     (g) CECI is not obligated to deliver hydrocarbons produced from the Britt
Ranch Properties at some future time without then or thereafter receiving full
payment for the production attributable to CECI's ownership in and to the Britt
Ranch Properties by virtue of: (i) a prepayment arrangement under any contract
for the sale of hydrocarbons and containing a "take or pay," or similar
provisions, (ii) a production payment, or (iii) any other arrangement.

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     (h) Except for those taxes and assessments for which an adjustment is made
under Section 2.2(b)(v), during the period of CECI's ownership of the Britt
Ranch Properties, CECI has properly paid all ad valorem, property, production,
severance, excise and similar taxes and assessments based on or measured by the
ownership of property or the production of hydrocarbons or the receipt of
proceeds therefrom on the Britt Ranch Properties that have become due and
payable before the Effective Time.

     (i) No suit, action, claim, or other proceeding is pending or, to the best
of CECI's knowledge, threatened before any court, arbitration panel or
governmental agency which relates to the Britt Ranch Properties and which might
result in a material loss of CECI's title to any portion of the Britt Ranch
Properties, or a material diminution of the value of any of the Britt Ranch
Properties, or that might materially hinder or impede the operation of the Britt
Ranch Leases.

     (j) As used in this Agreement, the term, "Existing Documents" shall mean as
to CECI all of the oil, gas and other mineral leases, assignments or other
instruments or agreements that comprise the Britt Ranch Properties, and all
contractually binding arrangements to which the Britt Ranch Properties may be
subject and which will be binding on the Britt Ranch Properties or P&L LP after
Closing (including, without limitation, oil, gas and other mineral leases,
overriding royalty assignments, farm-out and farm-in agreements, option
agreements, forced pooling orders, assignments of production payments,
partnership agreements, unit agreements, unit operating agreements, joint
operating agreements, balancing agreements, unit operating agreements,
production contracts, processing contracts, gas sales contracts, marketing and
transportation contracts and division orders). To the best of CECI's knowledge,
(i) all Existing Documents are in full force and effect and are the valid and
legally binding obligations of the parties thereto and are enforceable in
accordance with their respective terms (subject to the effects of bankruptcy,
insolvency, reorganization, moratorium and similar laws); (ii) CECI is not in
material breach or default with respect to any of its obligations pursuant to
any such Existing Documents; and (iii) all payments (including, without
limitation, royalties, delay rentals, shut-in royalties and valid calls under
unit or operating agreements) due thereunder have been timely paid and CECI has
received no notice of default under any of the Existing Documents.

     (k) Prior to Closing, CECI will have inspected the Frisco City Properties,
the public records and P&L Inc.'s files for all purposes, including, but not
limited to, detecting the presence and concentration of naturally-occurring
radioactive materials and satisfying itself as to the physical condition and
environmental condition of the Frisco City Properties, both surface and
subsurface. In entering into this Agreement, CECI has relied solely on the
express representations and covenants of P&L Inc. in this Agreement, its
independent investigation of, and judgment with respect to, the Frisco City
Properties and the advice of its own legal, tax, economic, environmental,
engineering, geological and geophysical advisors, and not on any comments or
statements of any representatives of, or consultants or advisors engaged by P&L
Inc.

     (l) At Closing, CECI will meet the requirements required by all
governmental authorities in respect to the Frisco City Properties, if any, and,
after Closing, CECI anticipates that it will continue to be able to meet such
requirements. CECI is, and after the Closing is expected to

                                      -10-
<PAGE>

continue to be, otherwise qualified to own the Frisco City Properties. The
consummation of the transactions contemplated hereby will not cause CECI to be
disqualified to be an owner of oil, gas, and mineral leases or to exceed any
acreage limitation imposed by law, statute, rule or regulation. CECI is not
aware of any fact that could reasonably be expected to cause the appropriate
governmental authorities to fail to unconditionally approve the assignment of
the Frisco City Properties to CECI.

     (m) CECI is an experienced and knowledgeable investor and operator in the
oil and gas business. CECI is acquiring the Frisco City Properties for its own
account and not with a view to, or for offer of resale in connection with, a
distribution thereof, within the meaning of the Securities Act of 1933, as
amended, or any other rules, regulations, and laws pertaining to the
distribution of securities.

     (n) CECI has arranged or will have arranged to have available by the
Closing Date sufficient funds to enable the payment to P&L Inc., by wire
transfer, of the Adjusted Frisco City Payment in accordance with Section 2.3 and
to otherwise perform CECI's obligations under this Agreement.

     (o) To the best of CECI's knowledge:

          (i)  CECI's activities with respect to the Britt Ranch Properties
               comply in all respects with all applicable governmental laws,
               including, without limitation, health and safety statutes and
               regulations and all Environmental Laws, including any provisions
               requiring notice to government agencies under Environmental Laws.

          (ii) There is no civil, criminal or administrative action, suit,
               demand, claim, hearing, notice of violation, investigation,
               proceeding, notice or demand letter ("Environmental Proceeding")
               known to CECI pending or threatened against CECI or any of the
               Britt Ranch Properties relating in any way to the Environmental
               Laws.

         (iii) Neither CECI nor any other person have released, placed, stored,
               buried or dumped any Hazardous Substances, Oil, Pollutants or
               Contaminants or any other wastes on, beneath, or adjacent to the
               Britt Ranch Leases, except for inventories of such substances to
               be used in the ordinary course of business of CECI (which
               inventories and wastes, if any, were and are stored or disposed
               of in accordance with applicable laws and regulations).

          (iv) CECI has not received any notice or order from any governmental
               or other public agency advising it that CECI is responsible for
               or potentially responsible for Cleanup or paying for the cost of
               Cleanup of any Hazardous Substances, Oils, Pollutants, or
               Contaminants or

                                      -11-
<PAGE>



               any  other waste or substance affecting the Britt Ranch
               Properties. CECI is not aware of any facts which might reasonably
               give rise to any such notice or order.

     3.2 Representations and Warranties of P&L LP. P&L LP represents and
warrants to CECI the following:

     (a) P&L LP is a limited partnership, duly organized, validly existing and
in good standing under the laws of the State of Texas and is duly qualified to
conduct business in the State of Texas.

     (b) P&L LP has all requisite power and authority to carry on its business
as presently conducted, to enter into this Agreement, to purchase the Britt
Ranch Properties on the terms described in this Agreement and to perform its
other obligations under this Agreement.

     (c) The execution, delivery and performance of this Agreement and the
transactions contemplated hereby have been duly and validly authorized.

     (d) This Agreement has been duly executed and delivered by or on behalf of
P&L LP; all documents and instruments required hereunder to be executed and
delivered by P&L LP at or prior to Closing shall have been duly executed and
delivered; and this Agreement does, and such documents and instruments shall,
constitute legal, valid and binding obligations of P&L LP enforceable in
accordance with their terms.

     (e) P&L LP has incurred no liability, contingent or otherwise, for broker's
or finder's fees or commissions relating to the transactions contemplated by
this Agreement for which CECI shall have any responsibility whatsoever.

     (f) Prior to Closing, P&L LP will have inspected the Britt Ranch
Properties, the public records and CECI's files for all purposes, including, but
not limited to, detecting the presence and concentration of naturally-occurring
radioactive materials and satisfying itself as to the physical condition and
environmental condition of the Britt Ranch Properties, both surface and
subsurface. In entering into this Agreement, P&L LP has relied solely on the
express representations and covenants of CECI in this Agreement, its independent
investigation of, and judgment with respect to, the Britt Ranch Properties and
the advice of its own legal, tax, economic, environmental, engineering,
geological and geophysical advisors, and not on any comments or statements of
any representatives of, or consultants or advisors engaged by CECI.

     (g) At Closing, P&L LP will meet the requirements required by all
governmental authorities in respect to the Britt Ranch Properties, if any, and,
after Closing, P&L LP anticipates that it will continue to be able to meet such
requirements. P&L LP is, and after the Closing is expected to continue to be,
otherwise qualified to own the Britt Ranch Properties. The consummation of the
transactions contemplated hereby will not cause P&L LP to be disqualified to be
an owner of oil, gas, and mineral leases or to exceed any acreage limitation
imposed by law,

                                      -12-
<PAGE>

statute, rule or regulation. P&L LP is not aware of any fact that could
reasonably be expected to cause the appropriate governmental authorities to fail
to unconditionally approve the assignment of the Britt Ranch Properties to P&L
LP.

     (h) P&L LP is an experienced and knowledgeable investor and operator in the
oil and gas business. P&L LP is acquiring the Britt Ranch Properties for its own
account and not with a view to, or for offer of resale in connection with, a
distribution thereof, within the meaning of the Securities Act of 1933, as
amended, or any other rules, regulations, and laws pertaining to the
distribution of securities.

     (i) P&L LP has arranged or will have arranged to have available by the
Closing Date sufficient funds to enable the payment to CECI, by wire transfer,
of the Adjusted Britt Ranch Payment in accordance with Section 2.2 and to
otherwise perform P&L LP's obligations under this Agreement.


     3.3 Representations and Warranties of P&L Inc. P&L Inc. represents and
warrants to CECI the following:

     (a) P&L Inc. is a corporation duly organized, validly existing and in good
standing under the laws of the State of Texas and is duly qualified to carry on
its business in Texas.

     (b) P&L Inc. has all requisite power and authority to carry on its business
as presently conducted and to enter into this Agreement and to perform its
obligations hereunder.

     (c) The execution, delivery and performance of this Agreement and the
transactions contemplated herein have been duly and validly authorize by P&L
Inc.

     (d) This Agreement has been duly executed and delivered on behalf of P&L
Inc., and all documents and instruments required hereunder to be executed and
delivered by P&L Inc. at or prior to Closing shall have been duly executed and
delivered. This Agreement does, and such documents and instruments shall,
constitute legal, valid and binding obligations of P&L Inc. enforceable in
accordance with their terms.

     (e) P&L Inc. has incurred no liability, contingent or otherwise, for
broker's or finder's fees or commissions relating to the transactions
contemplated by this Agreement for which CECI shall have any responsibility
whatsoever.

     (f) There are no outstanding authorizations for expenditures ("AFEs") that
(i) require the drilling of wells or other material development operations in
order to earn or to continue to hold all or any portion of the Frisco City
Properties, or (ii) obligate P&L Inc. to make payments of any amounts in
connection with drilling of wells or other material capital expenditures
affecting the Frisco City Properties.

                                      -13-
<PAGE>

     (g) P&L Inc. is not obligated to deliver hydrocarbons produced from the
Frisco City Properties at some future time without then or thereafter receiving
full payment for the production attributable to P&L Inc.'s ownership in and to
the Frisco City Properties by virtue of: (i) a prepayment arrangement under any
contract for the sale of hydrocarbons and containing a "take or pay," or similar
provisions, (ii) a production payment, or (iii) any other arrangement.

     (h) Except for those taxes and assessments for which an adjustment is made
under Section 2.2(b)(v), during the period of P&L Inc.'s ownership of the Frisco
City Properties, P&L Inc. has properly paid all ad valorem, property,
production, severance, excise and similar taxes and assessments based on or
measured by the ownership of property or the production of hydrocarbons or the
receipt of proceeds therefrom on the Frisco City Properties that have become due
and payable before the Effective Time.

     (i) No suit, action, claim, or other proceeding is pending or, to the best
of P&L Inc.'s knowledge, threatened before any court, arbitration panel or
governmental agency which relates to the Frisco City Properties and which might
result in a material loss of P&L Inc.'s title to any portion of the Frisco City
Properties, or a material diminution of the value of any of the Frisco City
Properties, or that might materially hinder or impede the operation of the
Frisco City Leases.

     (k) As used in this Agreement, the term, "Existing Documents" shall mean as
to P&L Inc. all of the oil, gas and other mineral leases, assignments or other
instruments or agreements that comprise the Frisco City Properties, and all
contractually binding arrangements to which the Frisco City Properties may be
subject and which will be binding on the Frisco City Properties or P&L Inc.
after Closing (including, without limitation, oil, gas and other mineral leases,
overriding royalty assignments, farm-out and farm-in agreements, option
agreements, forced pooling orders, assignments of production payments,
partnership agreements, unit agreements, unit operating agreements, joint
operating agreements, balancing agreements, unit operating agreements,
production contracts, processing contracts, gas sales contracts, marketing and
transportation contracts and division orders). To the best of P&L Inc.'s
knowledge, (i) all Existing Documents are in full force and effect and are the
valid and legally binding obligations of the parties thereto and are enforceable
in accordance with their respective terms (subject to the effects of bankruptcy,
insolvency, reorganization, moratorium and similar laws); (ii) P&L Inc. is not
in material breach or default with respect to any of its obligations pursuant to
any such Existing Documents; and (iii) all payments (including, without
limitation, royalties, delay rentals, shut-in royalties and valid calls under
unit or operating agreements) due thereunder have been timely paid and P&L Inc.
has received no notice of default under any of the Existing Documents.

     (l) To the best of P&L Inc.'s knowledge:

          (i)  P&L Inc.'s activities with respect to the Frisco City Properties
               comply in all respects with all applicable governmental laws,
               including, without limitation, health and safety statutes and
               regulations and all Environmental Laws, including any provisions
               requiring notice to government agencies under Environmental Laws.

                                      -14-
<PAGE>


          (ii) There is no civil, criminal or administrative action, suit,
               demand, claim, hearing, notice of violation, investigation,
               proceeding, notice or demand letter ("Environmental Proceeding")
               known to P&L Inc. pending or threatened against P&L Inc. or any
               of the Frisco City Properties relating in any way to the
               Environmental Laws.

         (iii) Neither P&L Inc. nor any other person have released, placed,
               stored, buried or dumped any Hazardous Substances, Oil,
               Pollutants or Contaminants or any other wastes on, beneath, or
               adjacent to the Frisco City Leases, except for inventories of
               such substances to be used in the ordinary course of business of
               P&L Inc. (which inventories and wastes, if any, were and are
               stored or disposed of in accordance with applicable laws and
               regulations).

          (iv) P&L Inc. has not received any notice or order from any
               governmental or other public agency advising it that P&L Inc. is
               responsible for or potentially responsible for Cleanup or paying
               for the cost of Cleanup of any Hazardous Substances, Oils,
               Pollutants, or Contaminants or any other waste or substance
               affecting the Frisco City Properties. P&L Inc. is not aware of
               any facts which might reasonably give rise to any such notice or
               order.

                                    ARTICLE 4
                           CERTAIN AGREEMENTS OF CECI

     4.1 Agreements Between Execution of Agreement and Closing. During the
period between the execution of this Agreement and the Closing Date, CECI shall
not, without the prior written consent of P&L LP, (i) sell, convey, assign,
transfer or encumber any of the Britt Ranch Properties; (ii) make or agree to
make any expenditure in excess of $25,000.00, net to CECI's interest, except for
obligations under existing contracts, expenditures necessary to maintain the
Britt Ranch Properties, or in the event of any emergency as to which CECI has
notified P&L LP; (iii) sell oil, gas or other minerals from the Britt Ranch
Properties except sales made in the ordinary course of business; (iv) enter into
any agreement amending, modifying or terminating any of the leases under the
Britt Ranch Properties ; or (v) take any other action with respect to any of the
Britt Ranch Properties that would cause a material diminution in the value
thereof or that would materially and adversely affect the use and enjoyment
thereof.

     4.2 Access to Records. Following the execution of this Agreement by the
Parties, CECI shall afford to P&L LP and its authorized representatives, during
normal business hours, reasonable access to well and land files, title, contract
and legal materials and operating data and information in CECI's possession or
to which it has access affecting the Britt Ranch Properties.

                                      -15-
<PAGE>


     4.3 Notification of Additional Proceedings. CECI shall promptly notify P&L
LP of any new suits, actions, claims or other proceedings threatened or pending
before, or required to be filed with, any court, arbitrator or governmental
agency which relate to the Britt Ranch Properties.

     4.4 Consents. CECI shall use its best efforts to obtain any consents, if
any, necessary to transfer the Britt Ranch Properties to P&L LP.

     4.5 Cooperation. CECI shall cooperate with P&L LP and P&L Inc. to assist
P&L LP and P&L Inc. in carrying out the respective agreements of P&L LP and P&L
Inc. hereunder.

                                   ARTICLE 5
                   CERTAIN AGREEMENTS OF P&L LP AND P&L INC.

     5.1 Agreements Between Execution of Agreement and Closing. During the
period between the execution of this Agreement and the Closing Date, P&L Inc.
shall not, without the prior written consent of CECI, (i) sell, convey, assign,
transfer or encumber any of the Frisco City Properties; (ii) make or agree to
make any expenditure in excess of $25,000.00, net to P&L Inc.'s interest, except
for obligations under existing contracts, expenditures necessary to maintain the
Frisco City Properties, or in the event of any emergency as to which P&L Inc.
has notified CECI; (iii) sell oil, gas or other minerals from the Frisco City
Properties except sales made in the ordinary course of business; (iv) enter into
any agreement amending, modifying or terminating any of the leases under the
Frisco City Properties ; or (v) take any other action with respect to any of the
Frisco City Properties that would cause a material diminution in the value
thereof or that would materially and adversely affect the use and enjoyment
thereof.

     5.2 Access to Records. Following the execution of this Agreement by the
Parties, P&L Inc. shall afford to CECI and its authorized representatives,
during normal business hours, reasonable access to well and land files, title,
contract and legal materials and operating data and information in P&L Inc.'s
possession or to which it has access affecting the Frisco City Properties.

     5.3 Notification of Additional Proceedings. P&L Inc. shall promptly notify
CECI of any new suits, actions, claims or other proceedings threatened or
pending before, or required to be filed with, any court, arbitrator or
governmental agency which relate to the Frisco City Properties.

     5.4 Consents. P&L Inc. shall use its best efforts to obtain any consents,
if any, necessary to transfer the Frisco City Properties to CECI.

     5.5 Cooperation. P&L LP and P&L Inc. shall each cooperate with CECI to
assist CECI in carrying out the agreements of CECI hereunder.

                                      -16-
<PAGE>

                                    ARTICLE 6
                          CECI'S CONDITIONS TO CLOSING

     The obligations of CECI to consummate the transactions provided for herein
are subject, at the option of CECI, to the fulfillment on or prior to Closing of
each of the following conditions:

     6.1 Representations. The representations and warranties by P&L LP set forth
in Section 3.2 and by P&L Inc. set forth in Section 3.3 above shall be true and
correct in all material respects as of the date of this Agreement and as of the
Closing Date.

     6.2 Changes. There shall have been no material adverse change in the
physical condition of the Frisco City Properties, except depletion through
normal production within authorized allowable and rates of production,
depreciation of equipment through ordinary wear and tear, and other transactions
permitted under this Agreement or approved in writing by CECI.

     6.3 Performance. P&L LP and P&L Inc. shall have timely performed and
complied with all agreements and covenants required by this Agreement.

     6.4 No Legal Proceedings. No suit, action or other proceeding shall be
pending or threatened before any court, arbitration panel or governmental agency
seeking to restrain, prohibit or declare illegal, or seeking substantial damages
in connection with the purchase and sale contemplated by this Agreement, or
which might result in a material loss of any portion of the Frisco City
Properties, a material diminution in the value of any of the Frisco City
Properties, or materially interfere with the use or enjoyment of the Frisco City
Properties or (ii) any suit or proceeding affecting only a portion of the Frisco
City Properties, which portion could be treated as subject to a Title Defect in
accordance with Article 10.

     6.5 Existing Documents. CECI must be reasonably satisfied with the terms
and conditions of the Existing Documents.

                                    ARTICLE 7
                   P&L LP AND P&L INC.'s CONDITIONS TO CLOSING

     The obligations of P&L LP and P&L Inc. to consummate the transactions
provided for herein are subject, at the option of P&L LP and P&L Inc., to the
fulfillment on or prior to Closing of each of the following conditions:

     7.1 Representations. The representations and warranties by CECI set forth
in Section 3.1 above shall be true and correct in all material respects as of
the date of this Agreement and as of the Closing Date.

     7.2 Changes. There shall have been no material adverse change in the
physical condition of the Britt Ranch Properties, except depletion through
normal production within authorized

                                      -17-
<PAGE>

allowable and rates of production, depreciation of equipment through ordinary
wear and tear, and other transactions permitted under this Agreement or approved
in writing by P&L LP and P&L Inc.

     7.3 Performance. CECI shall have timely performed and complied with all
agreements and covenants required by this Agreement.

     7.4 No Legal Proceedings. No suit, action or other proceeding shall be
pending or threatened before any court, arbitration panel or governmental agency
seeking to restrain, prohibit or declare illegal, or seeking substantial damages
in connection with the purchase and sale contemplated by this Agreement, or
which might result in a material loss of any portion of the Britt Ranch
Properties, a material diminution in the value of any of the Britt Ranch
Properties, or materially interfere with the use or enjoyment of the Britt Ranch
Properties or (ii) any suit or proceeding affecting only a portion of the Britt
Ranch Properties, which portion could be treated as subject to a Title Defect in
accordance with Article 10.

     7.5 Existing Documents. P&L LP and P&L Inc. must be reasonably satisfied
with the terms and conditions of the Existing Documents.

                                    ARTICLE 8
                                     CLOSING

     8.1 Date of Closing. Subject to the conditions stated in this Agreement,
the purchase and sale of the Properties pursuant to this Agreement (the
"Closing") shall occur on or before September 6, 2000, at 10:00 a.m., Central
Standard Time, or on such other date and time as the Parties may agree (the
"Closing Date").

     8.2 Place of Closing. The Closing shall be held at the offices of CECI as
set forth hereinabove; provided, however, the Parties may agree to close via
facsimile or overnight mail.

     8.3 Closing Obligations. At the Closing, the following documents shall be
delivered and the following events shall occur, each event being a condition
precedent to the others and each being deemed to have occurred simultaneously
with the others:

          (i)  CECI shall execute and deliver: (1) an Assignment, Bill of Sale
               and Conveyance in the form attached hereto as Exhibit "E" (the
               "Britt Ranch Assignment") (in sufficient counterparts to
               facilitate recording) conveying the Britt Ranch Properties,
               subject to the Permitted Encumbrances; (2) such other instruments
               as may be required to convey the Britt Ranch Properties to P&L LP
               and otherwise effectuate the transactions contemplated by this
               Agreement.

          (ii) P&L Inc. shall execute and deliver: (1) an Assignment, Bill of
               Sale and Conveyance in the form attached hereto as Exhibit "F"
               (the "Frisco City Assignment") (in sufficient counterparts to
               facilitate recording) conveying the Frisco City Properties,
               subject to the Permitted Encumbrances; (2) such other

                                      -18-
<PAGE>



               instruments as may be required to convey the Frisco City
               Properties to CECI and otherwise effectuate the transactions
               contemplated by this Agreement.

         (iii) P&L LP shall deliver by cashiers check, direct bank or wire
               transfer to CECI or to CECI's account (at such place as may be
               designated by CECI in a written notice, such notice to be
               delivered to P&L LP not less than two (2) Business Days prior to
               the Closing) the Britt Ranch Purchase Price.

          (iv) CECI shall deliver by cashiers check, direct bank or wire
               transfer to P&L Inc. or to P&L Inc.'s account (at such place as
               may be designated by P&L Inc. in a written notice, such notice to
               be delivered to CECI not less than two (2) Business Days prior to
               the Closing) the Frisco City Purchase Price.

          (v)  CECI shall deliver on forms supplied by P&L LP transfer orders or
               letters in lieu thereof, directing the operator or purchaser to
               make payment of proceeds attributable to production from the
               Britt Ranch Properties after the Effective Time to P&L LP.

     8.4 Records.

     (a) In addition to the obligations set forth under Sections 4.2 and 8.3
above, within thirty (30) days after Closing, CECI shall deliver to P&L LP all
original well and land files regarding the Britt Ranch Properties in its
possession or to which it has access. P&L LP shall be entitled to all original
records affecting the Britt Ranch Properties assigned to P&L LP pursuant to the
terms of this Agreement. CECI shall be entitled to keep a copy of such records
for its files. P&L LP agrees to preserve and maintain such records for at least
five (5) years after the Closing Date and to provide CECI access to such records
during normal business hours during such period.

     (b) In addition to the obligations set forth under Sections 5.2 and 8.3
above, within thirty (30) days after Closing, P&L Inc. shall deliver to CECI all
original well and land files regarding the Frisco City Properties in its
possession or to which it has access. CECI shall be entitled to all original
records affecting the Frisco City Properties assigned to CECI pursuant to the
terms of this Agreement. P&L Inc. shall be entitled to keep a copy of such
records for its files. CECI agrees to preserve and maintain such records for at
least five (5) years after the Closing Date and to provide P&L LP access to such
records during normal business hours during such period.

                                    ARTICLE 9
                              POST-CLOSING MATTERS

     9.1 Final Settlement Statement. Within ninety (90) days after Closing, CECI
shall prepare and deliver to P&L LP and P&L Inc., in accordance with this
Agreement and generally accepted accounting principles, a statement ("Final
Settlement Statement") setting forth each adjustment (other than adjustments for
Title Defects) finally determined as of Closing and showing

                                      -19-
<PAGE>

the calculation of such adjustments. Within thirty (30) days after receipt of
the Final Settlement Statement, P&L LP and P&L Inc. shall deliver to CECI a
written report containing any changes that P&L LP and P&L Inc. propose be made
in good faith to resolve any questions with respect to the amounts due pursuant
to such Final Settlement Statement no later than one hundred twenty (120) days
after the Closing.

     9.2 Unpaid Third Party Funds. At such time as CECI, P&L LP and P&L Inc.
agree on a Final Settlement Statement,

     (a) CECI will transfer to P&L LP any funds held by CECI in suspense for any
third party owner of royalty, overriding royalty, working interests, mineral
interest or other similar interests, attributable to the Britt Ranch Properties,
and will deliver all records in CECI's possession, including a schedule of such
funds listing the owners thereof, which may be used to determine proper
disbursement. P&L LP shall thereafter be responsible for determining the proper
payment of such amounts and shall indemnify and hold harmless CECI from and
against any and all cost, loss or expense of whatever kind, including attorneys'
fees, arising from or in connection with the claim or any person, up to the
amount listed on the schedule provided by CECI with respect thereto, with
respect to the funds transferred to P&L LP pursuant to this Section 9.2(a).

     (b) P&L Inc. will transfer to CECI any funds held by P&L Inc. in suspense
for any third party owner of royalty, overriding royalty, working interests,
mineral interest or other similar interests, attributable to the Frisco City
Properties, and will deliver all records in P&L Inc.'s possession, including a
schedule of such funds listing the owners thereof, which may be used to
determine proper disbursement. CECI shall thereafter be responsible for
determining the proper payment of such amounts and shall indemnify and hold
harmless P&L Inc. from and against any and all cost, loss or expense of whatever
kind, including attorneys' fees, arising from or in connection with the claim or
any person, up to the amount listed on the schedule provided by P&L Inc. with
respect thereto, with respect to the funds transferred to CECI pursuant to this
Section 9.2(b).

     9.3 Further Assurances. After Closing, CECI, P&L LP and P&L Inc. shall
execute, acknowledge and deliver or cause to be executed, acknowledged and
delivered such instruments and take such other action as may be necessary or
advisable to carry out their obligations under this Agreement and under any
Exhibit, document, certificate or other instrument delivered pursuant hereto.

     9.4 Survival. All representations and warranties set forth in this
Agreement in Sections 3.1 (a) - (h), 3.2 (a) - (e) and 3.3 (a) - (h) shall
survive the Closing, but no other representations and warranties shall survive
the Closing.

                                      -20-
<PAGE>

                                   ARTICLE 10
                                  TITLE MATTERS

     10.1 Access to Title and Other Documents. After the date hereof, at CECI's
offices, CECI will make available to P&L LP and to its representatives; and at
P&L Inc.'s offices, P&L Inc. will make available to CECI and to its
representatives (such representatives of a Party to include employees,
consultants, independent contractors, attorneys and other advisors to that
Party) for copying and/or inspection (at the copying and/or inspecting Party's
cost and expense), during normal business hours, the following documents in the
respective possession or under the respective control of CECI as to the Britt
Ranch Properties or P&L Inc. as to the Frisco Ranch Properties:

          (i)  All abstracts of title, title opinions, title curative materials,
               ownership reports, division orders, bills of sale, other
               documents evidencing transfers of title, tax receipts, and
               licenses and registrations pertaining to such Property.

          (ii) All of the lease records, lease files, leases, conveyances and
               assignments of interest in the Leases under such Property;
               unitization, unit, pooling and operating agreements; division
               orders; contracts; transfer orders; orders of the applicable
               regulatory authorities or administrative agencies; mortgages,
               deeds of trust, security agreements, and financing statements;
               and all other contracts, agreements and documents affecting such
               Property.

         (iii) Instruments and documents concerning proper payment of all
               general and special assessments, ad valorem and property taxes,
               and production, severance and similar taxes and assessments based
               on or measured by the ownership of such Property, the production
               of hydrocarbons, or the receipt of proceeds therefrom for 1999
               and years prior for which the applicable statute of limitations
               has not expired.

          (iv) All geological maps, geophysical surveys, ownership maps, seismic
               surveys, logs, core studies, and surveys relating to such
               Property.

          (v)  All production records; transportation agreements; contracts
               concerning the purchase of gas, oil, casinghead gas, distillate,
               gas condensate or other hydrocarbons; processing agreements; all
               correspondence relating to such Properties; and data sheets
               relating to such Property and to bonuses, rentals and royalties
               payable with respect thereto.

          (vi) All agreements relating to the purchase, sale, processing, and
               transportation of production from the Wells under such Property.

         (vii) All bonds, leases, permits, easements, licenses, orders,
               saltwater disposal agreements, agreements with pumpers and other
               agreements in any way relating to such Property or the operation
               thereof.

                                      -21-
<PAGE>

Reliance on such information shall be at the sole risk of the respective Buyer
hereunder, and neither CECI or P&L LP makes any guaranty or representation as to
the accuracy or completeness of such data, except as otherwise provided in this
Agreement.

     Each Seller of a Property hereunder authorizes the respective Buyer thereof
, and its respective representatives to consult with attorneys, abstract
companies and other consultants or independent contractors of such Seller,
(whether utilized in the past or present) concerning title related matters.
Reliance on such information of such third parties shall be at the sole risk of
the the respective Buyer, and neither Seller makes any guaranty or
representation as to the accuracy or completeness of such data.

     10.2 No Warranty or Representation. At the Closing, CECI shall convey to
P&L LP all of the Britt Ranch Properties and P&L Inc. shall convey to CECI all
of the Frisco City Properties. Such conveyances shall be subject to the
Permitted Encumbrances and WITHOUT ANY WARRANTY OF TITLE, EITHER EXPRESS OR
IMPLIED, AND WHETHER BY COMMON LAW, STATUTE OR OTHERWISE, except for the
warranty of title as to persons claiming by, through and under the respective
Seller and the warranty against liens and mortgages, both as contained in the
Assignment. Without limiting the respective P&L LP's right to reduce the Britt
Ranch Payment or CECI's right to reduce the Frisco City Payment in the manner
provided in this Article 10, neither Seller makes any warranty or
representation, express or implied, with respect to the accuracy or completeness
of any information. Records or data now, heretofore, or hereafter made available
to each Buyer in connection with this Agreement, including, without limitation,
any description of the Properties, pricing assumptions, potential for production
of hydrocarbons from the Properties, or any other matters contained in any
material furnished by either Seller to either Buyer or their respective
officers, directors, employees, agents, advisors or representatives.

     10.3 Disclaimer. ALL PERSONAL PROPERTY, MACHINERY, FIXTURES, EQUIPMENT AND
MATERIALS CONVEYED HEREBY ARE SOLD AND ASSIGNED AND ACCEPTED BY BUYER IN THEIR
"WHERE IS, AS IS" CONDITION, WITHOUT ANY WARRANTIES, EXPRESS OR IMPLIED OR
STATUTORY, OF MARKETABILITY, QUALITY, CONDITION, MERCHANTABILITY AND/OR FITNESS
FOR A PARTICULAR PURPOSE OR USE, ALL OF WHICH ARE EXPRESSLY DISCLAIMED.

     10.4 Permitted Encumbrances. As used in this Agreement, the term "Permitted
Encumbrances" shall mean the following, provided that the same shall not operate
to reduce the net revenue interest or increase the gross working interest of a
Property beyond that shown on Exhibit "A"or Exhibit "B":

     (a) Lessors' royalties, non-participating royalties, overriding royalties,
division orders, reversionary interests, and similar burdens.

     (b) Preferential rights to purchase and required third party consents to
assignments and similar agreements, with respect to which, prior to Closing (i)
waivers or consents are obtained from the appropriate parties, (ii) the
appropriate time period for asserting such rights has expired

                                      -22-
<PAGE>

without an exercise of such rights, or (iii) arrangements acceptable to the
respective Buyer can be made by such Buyer and the respective Seller to allow
such Buyer to receive substantially the same economic benefits as if all such
waivers and consents to assign have been obtained.

     (c) Liens for taxes or assessments not yet due or delinquent or, if
delinquent, that are being contested in good faith in the normal course of
business.

     (d) All rights to consent by, required notices to, filing with, or other
actions by governmental entities in connection with the sale or conveyance of
oil and gas leases or interests therein, if the same are customarily obtained
subsequent to such sale or conveyance and neither the respective Seller nor
Buyer has no reason to believe they cannot be obtained.

     (e) Such Title Defects as the respective Buyer may have waived in writing.

     (f) Rights reserved to or vested in any governmental authority.

     (g) Rights of a common owner of any Property in rights-of-way or easements
currently held by the respective Seller and such common owner as tenants in
common or through common ownership.

     (h) Easements, conditions, covenants, restrictions, servitudes, permits,
rights-of-way, surface leases and other rights in the Properties for the
purpose of surface operations, roads, alleys, highways, railways, pipelines,
transmission lines, transportation lines, distribution lines, power lines,
telephone lines, and removal of timber, grazing, logging operations, canals,
ditches, reservoirs and other like purposes, or for the joint or common use of
real estate, rights-of-way, facilities and equipment which do not materially
impair the rights held by the respective Buyer or the use and enjoyment of the
Property.

     (i) Defects, irregularities and deficiencies in title to any rights-of-way,
easements, surface lease or other rights which in the aggregate do not
materially impair the use of such right-of-way, easements, surface leases or
other rights for the purpose of which such rights will be held by the respective
Buyer.

     (j) Zoning, planning and environmental laws and ordinances and municipal
regulations.

     (k) Vendors, carriers, warehousemen, repairmen, mechanics, workmen,
materialmen, construction or other like liens arising by operation of law in the
ordinary course of business or incident to the construction or improvement of
any property in respect of obligations which are not yet due, or which are being
contested in good faith by appropriate proceedings by or on behalf of the
respective Seller.

                                      -23-
<PAGE>

     (l) Liens created under operating agreements in respect of obligations that
are not yet due or that are being contested in good faith by appropriate
proceedings by or on behalf of the respective Seller.

     (m) The terms and provisions of the Existing Documents.

     10.5 Good and Defensible Title. For the purposes of this Article 10, the
term "Good and Defensible Title" shall mean, with respect to each of the
Properties, that title of CECI with respect to the Britt Ranch Properties and of
P&L Inc. with respect to the Frisco City Properties which, subject to and except
for Permitted Encumbrances:

     (a) Entitles the respective Seller, throughout the duration of the relevant
Property, to receive from such Property (free and clear of all royalties,
overriding royalties, non-participating royalties, net profits interests, or
other burdens on or measured by production of hydrocarbons) not less than the
interest shown as the net revenue interest on Exhibit "A"or Exhibit "B", as
appropriate, in all hydrocarbons produced, saved and marketed from the Property
and of all hydrocarbons produced, saved, and marketed from any unit of which the
Property is a part and which is allocated to such Property; all without
reduction, suspension, or termination of the Property.

     (b) Obligates each respective Seller to bear the percentage of the costs
and expenses relating to the maintenance and development of, and operations
relating to, the Property not greater than the gross working interest shown on
Exhibit "A" or Exhibit "B", as appropriate, without increase throughout the
duration of such Property.

     (c) Is free and clear of liens, encumbrances and defects.

     (d) All irregularities of title that would not reasonably be expected to
result in claims that would materially and adversely affect each Seller's title
to a Property shall not be considered a Title Defect, including but not limited
to (i) defects in the chain of title consisting of failure to recite marital
status or the omission of succession or heirship proceedings; (ii) defects or
irregularities arising out of prior oil and gas leases which, on their face,
expired more than three (3) years prior to the Effective Time, and which have
not been released of record; (iii) defects or irregularities arising out of
acknowledgments, questions of identity, trusts or trustees, executors and
personal representatives, and the manner in which they executed documents or
were identified thereon; (iv) defects or irregularities arising out of mortgages
or deeds of trust which, by their terms, matured more than six (6) years prior
to the Effective Time but which remain unreleased of record; (v) defects or
irregularities arising out of the lack of survey of specific land or lease
description; (vi) defects or irregularities arising out of the lack of recorded
powers of attorneys from corporations, banks, trusts or personal representatives
to execute and deliver documents on their behalf or on behalf of others; (vii)
defects or irregularities cured by possession under applicable statutes of
limitation and statutes relating to prescription.

     10.6 Notice of Title Defect. Except for Permitted Encumbrances, any defect
in title, lien, encumbrance, or defect that would cause either Seller's title to
any Property not to be Good and

                                      -24-
<PAGE>


Defensible Title shall be a title defect ("Title Defect"). Not later than thirty
(30) days following the Closing Date (the "Warranty Claim Date"), each
respective Buyer must notify the corresponding Seller in writing of any matter
that such Buyer considers to be a Title Defect ("Notice of Title Defect"), which
notice shall include, (i) a specific description of the matter such Buyer
asserts as a Title Defect, (ii) a specific description of the Property or the
portion of the Property that is affected by the Title Defect, (iii) such Buyer's
calculation of the amount ("Title Defect Amount") that the value of the Property
should be reduced because of the Title Defect based on the Allocated Value shown
on Exhibit "C" with respect to the Britt Ranch Property or Exhibit "D" with
respect to the Frisco City Property and (iv) appropriate supporting
documentation.

     Notwithstanding anything to the contrary in this Agreement, each Buyer
shall be deemed to have waived any Title Defect which such Buyer has not
specifically asserted in its Notice of Title Defect presented before the
Warranty Claim Date.

     10.7 Title Failure. Any item that CECI acknowledges is a Title Defect but
that CECI is unwilling to cure shall be deemed a title failure ("Title Failure")
and, subject to Section 10.9 below, the Adjusted Britt Ranch Payment shall be
reduced for such Title Defect pursuant to Section 2.2 unless, in CECI's
reasonable judgment, it is unlikely that material losses, costs, expenses and
liabilities will be experienced with respect to such Title Defect and CECI
agrees to indemnify P&L LP with respect thereto. Any item that P&L Inc.
acknowledges is a Title Defect but that P&L Inc. is unwilling to cure shall be
deemed a title failure ("Title Failure") and, subject to Section 10.9 below, the
Adjusted Frisco City Payment shall be reduced for such Title Defect pursuant to
Section 2.3 unless, in P&L Inc.'s reasonable judgment, it is unlikely that
material losses, costs, expenses and liabilities will be experienced with
respect to such Title Defect and P&L Inc. agrees to indemnify CECI with respect
thereto.

     10.8 Defect Notice; Sellers' Opportunity to Cure. To the extent that either
Seller disputes that any item described in the Notice of Title Defect actually
constitutes a Title Defect or disputes the Title Defect Amount assigned by Buyer
to any such Title Defect ("Contested Defect"), such Seller shall deliver to the
respective Buyer a notice so stating ("Defect Notice"). Subject to the
provisions of 10.9 below, the portion of the respective purchase price, as set
forth in Section 2.1 hereof, attributable to Title Defects which Sellers are
willing to cure but which are uncured at Closing, or which are not waived by
such Buyer at Closing (including Contested Defects), shall be deposited into an
escrow account pursuant to an escrow agreement agreed to by the Parties and the
Assignment will be revised to delete all of that portion of the respective
Property affected by such Title Defects (including Contested Defects). If a
Seller fails to cure a Title Defect within ninety (90) days after Closing, it
shall be deemed a Title Failure and the funds attributable to such Title Defect
shall be released from escrow to the appropriate Buyer and the Property on which
such Title Defect exists shall not be conveyed to such Buyer.

     10.9 Title Purchase Price Adjustments. Notwithstanding any provision hereof
to the contrary, there shall be no reduction in (a) the Britt Ranch Payment for
Title Failures and no escrow for Title Defects or Contested Defects unless and
until the aggregate amount of such Title Defects (including Title Failures and
Contested Defects) exceeds four percent (4%) of the Britt Ranch

                                      -25-
<PAGE>

Payment and only for the amount in excess of such amount or (b) the Frisco City
Payment for Title Failures and no escrow for Title Defects or Contested Defects
unless and until the aggregate amount of such Title Defects (including Title
Failures and Contested Defects) exceeds four percent (4%) of the Frisco City
Payment and only for the amount in excess of such amount.

     10.10 Termination Amount. Notwithstanding any provision hereof to the
contrary, in the event the aggregate adjustments for Title Defects pursuant to
this Article 10 and for Environmental Defects pursuant to Article 11 amount to
twenty percent (20%) or more of either of the Adjusted Britt Ranch Payment or
the Adjusted Frisco City Payment (the "Termination Amount"), either Party shall
have the option to terminate this Agreement, without any liability, upon written
notice to the other Party.

     10.11 Preferential Rights and Consents to Assign. Neither Property is
subject to an preferential right to purchase such Property or a requirement for
consents to assign such Property. Nonetheless, each Buyer shall notify the
respective Seller of any consent requirement or preferential right to purchase
it discovers prior to Closing. If a preferential right is exercised or a consent
is denied prior to Closing, the purchase price as described in Section 1.2 shall
be adjusted downward in an amount equal to the price paid to the Seller for the
Property with respect to which the preferential right has been exercised or the
consent has been denied and such Property shall be deleted from this Agreement.
In the case of a preferential right to purchase, each Seller shall be entitled
to all proceeds paid by the third party exercising its preferential right to
purchase. If a third party preferential purchase right burdening any Property
has not been exercised or waived by Closing, the Buyer therefor shall pay for
and accept an assignment covering such Property and, if the preferential right
is exercised after Closing, such Buyer shall be entitled to all proceeds paid
for such interest by the third party exercising such preferential purchase right
and such Buyer shall be responsible for conveying title to the Property affected
by said preferential right to the party exercising the same and shall indemnify
and hold the respective Seller harmless from and against any claim or liability
for such Buyer's failure to make such conveyance.


                                   ARTICLE 11
                                  ENVIRONMENTAL

     11.1 Inspection; Indemnity. Either Buyer and its authorized
representatives, at its sole risk and expense, shall have the right to enter
upon and inspect the real and personal properties comprising the Property which
it is acquiring under this Agreement, and to conduct such well, environmental
and other tests and assessments as such Buyer shall deem appropriate, subject to
the approval of the operator in the case of the Britt Ranch Properties. Such
Buyer shall repair any damages to said Property resulting from its inspection
and shall defend and hold the respective Seller harmless from and against any
and all losses, damages, claims, obligations, liabilities, expenses (including
court costs and attorneys' fees) or causes of action directly resulting from
such Buyer's inspection of the Property.

                                      -26-
<PAGE>

     11.2 Environmental Assessment. As part of its inspection of a Property, a
Buyer hereunder and its authorized representatives shall have the right to
conduct soil and water tests and borings, and generally to conduct such tests,
examinations, investigations and studies as may be necessary or appropriate in
such Buyer's sole judgment to make an environmental assessment of the Property
that is acquiring under this Agreement. Such Buyer shall keep any data or
information acquired through such examination and the results of all analyses of
such data and information strictly confidential and shall not disclose the same
to any person or agency without the prior written approval of the corresponding
Seller unless such disclosure is required by law. Each Buyer shall take all
steps necessary to ensure that its respective authorized representatives comply
with the provisions of this Article 11. If a Buyer has discovered in its
environmental assessment circumstances which require remediation, control or
other response under environmental laws, rules or regulations then in effect (an
"Environmental Defect"), such Buyer shall notify the corresponding Seller of
such circumstances as soon as practicable, but in no event less than five (5)
days prior to Closing.

     11.3 Environmental Defects If a Buyer properly notifies a Sellers of an
Environmental Defect related to a Property, such Buyer may (i) waive the
Environmental Defect and Close, or (ii) request that the Seller cure the
Environmental Defect. If a Buyer asks a Seller to cure an Environmental Defect,
and if the aggregate amount of all such Environmental Defects exceeds four
percent (4%) of the purchase price for the Property described in Section 1.2
hereof, the Seller has the option (i) to cure the Environmental Defect, or (ii)
to exclude the Property affected by the Environmental Defect from this
Agreement. If a Seller elects to cure the Environmental Defect, but the cure has
not been completed by Closing, the Property affected by the Environmental Defect
shall not be conveyed to Buyer at Closing, the purchase price for the Property
described in Section 1.2 hereof shall be reduced by the amount allocated to such
Property and such amount shall be deposited into the escrow account referred to
in Section 10.7. If the Environmental Defect is cured within ninety (90) days
after Closing, within five (5) days after the Environmental Defect is cured, the
respective Seller will convey to such Buyer the Property affected by the
Environmental Defect and the applicable amount shall be released from escrow to
the Seller. If the Seller elects to exclude the Property affected by the
Environmental Defect from this Agreement, subject to Section 11.4 below, the
purchase price for the Property described in Section 1.2 hereof will be reduced
by the allocated value of the Property affected.

     11.4 Environmental Purchase Price Adjustment. Notwithstanding any provision
hereof to the contrary, there shall be no reduction in the Purchase Price for
uncured Environmental Defects unless, and only to the extent that, the aggregate
amount of such uncured Environmental Defects exceeds four percent (4%) of the
Purchase Price and then only for the amount in excess of such amount.

     11.5 Environmental Defined Terms. As used in this Agreement:

     (a) The term "Cleanup" shall mean all actions required to: (1) cleanup,
remove, treat or remediate Hazardous Substances, Oils, Pollutants or
Contaminants; (2) prevent the Release of Hazardous Substances, Oils, Pollutants
or Contaminants so that they do not migrate, endanger or

                                      -27-
<PAGE>

threaten to endanger public health or welfare or the environment; (3) perform
pre-remedial studies and investigations and post-remedial monitoring and care;
or (4) respond to any government requests for information or documents in any
way relating to cleanup, removal, treatment or remediation or potential cleanup,
removal, treatment or remediation of Hazardous Substances, Oils, Pollutants or
Contaminants in the indoor or outdoor environment.

     (b) The term "Environmental Laws" shall mean all foreign, Federal, state
and local laws, regulations, rules and ordinances relating to polluting or
protection of the environment, including, without limitation, laws relating to
Releases or threatened Releases of Hazardous Substances, Oil, Pollutants or
Contaminants into the indoor or outdoor environment (including, without
limitation, ambient air, surface water, groundwater, land, surface and
subsurface strata) or otherwise relating to the manufacture, processing,
distribution, use, treatment, storage, Release, transport or handling of
Hazardous Substances, Oil, Pollutants or Contaminants, and all laws and
regulations with regard to record keeping, notification, disclosure and
reporting requirements respecting Hazardous Substances, Oils, Pollutants or
Contaminants. The term "Hazardous Substances, Oils, Pollutants or Contaminants"
shall mean all substances defined as such in the National Oil and Hazardous
Substances Pollution Contingency Plan, or defined as such by, or regulated as
such under, any Environmental Law.

     (c) The term "Release" or "Releases" means any release, spill, emission,
discharge, leaking, pumping, injection, deposit, disposal, discharge, dispersal,
leaching or migration into the indoor or outdoor environmental (including,
without limitation, ambient air, surface water, groundwater, and surface or
subsurface strata) or into or out of any property, including the movement of
Hazardous Substances, Oils, Pollutants or Contaminants through or in the air,
soil, surface water, groundwater or property.

                                   ARTICLE 12
                        TERMINATION, DEFAULT AND REMEDIES

     12.1 Right of Termination. The Agreement and all transactions contemplated
herein may be terminated at any time at or prior to Closing:

          (i)  By CECI, at CECI's option, in the event any of the conditions set
               forth in Article 7 have not been satisfied as provided therein.

          (ii) By P&L LP and P&L Inc., at their joint but not several option, in
               the event any of the conditions set forth in Article 6 have not
               been satisfied as provided therein.

         (iii) By either Party in the event that the adjustments to the
               purchase price described in Section 1.2 hereof for either
               Property exceeds the Termination Amount, as provided for in
               Section 10.10.

          (iv) At any time by the mutual written agreement of the Parties.

                                      -28-
<PAGE>

     12.2 Effect of Termination. In the event of the termination of this
Agreement by CECI pursuant to Section 12.1 (i) hereof due to either of P&L LP or
P&L Inc.'s failure to meet a condition of Closing, CECI may terminate this
Agreement as its sole remedy. In the event P&L LP and P&L Inc. terminate this
Agreement pursuant to Section 12.1 (ii) hereof due to CECI's failure to meet a
condition of Closing, P&L LP and P&L Inc. may terminate this Agreement as their
sole remedy. In the event of the termination of this Agreement pursuant to
either Section 12.1 (iii) or (iv) hereof, the termination shall be without
penalty and the Parties shall have no further obligations to, nor rights
against.

     12.3 Dispute Resolution. If the Parties disagree as to the cause for
termination, they will first attempt to resolve such disagreement through a
meeting, to be held within ten (10) days of such termination, of senior
executives of each party, and if such meeting fails to resolve the matter,
through a neutral arbitrator appointed by such executives within thirty (30)
days of the date of such meeting.

     12.4 Return of Documentation. Upon termination of this Agreement, P&L LP
shall return to CECI all title, geological data, reports, contracts, and maps
and other information, and all copies thereof furnished by CECI to P&L LP and
CECI shall return to P&L Inc. all title, geological data, reports, contracts,
and maps and other information, and all copies thereof furnished by P&L Inc. to
CECI.

                                   ARTICLE 13
                            ASSUMPTION OF OBLIGATIONS

     13.1 Assumption of Obligations. At Closing:

     (a) P&L LP shall assume (i) the obligation to (A) plug and abandon or
remove and dispose of all Britt Ranch Wells (whether then producing or
temporarily or permanently abandoned), platforms, structures, flow lines,
pipelines, and the other equipment now or hereafter located on the Britt Ranch
Properties; (B) cap and bury all flow lines and (C) dispose of other pipelines
now or hereafter located on the Britt Ranch Properties, and all other
pollutants, wastes, contaminants, or hazardous, extremely hazardous, or toxic
materials, substances, chemicals or wastes now or hereafter located on the Britt
Ranch Properties; (ii) all obligations and liabilities arising from or in
connection with any gas production, pipeline, storage, processing or other
imbalance attributable to substances produced from the Britt Ranch Properties on
or after the Effective Time; and (iii) all other costs, obligations and
liabilities that relate to the Britt Ranch Properties and, in each case, arise
from or relate to events occurring on or after the Effective Time.

     (b) CECI shall assume (i) the obligation to (A) plug and abandon or remove
and dispose of all Frisco City Wells (whether then producing or temporarily or
permanently abandoned), platforms, structures, flow lines, pipelines, and the
other equipment now or hereafter located on the Frisco City Properties; (B) cap
and bury all flow lines and (C) dispose of other pipelines now or hereafter
located on the Frisco City Properties, and all other pollutants, wastes,
contaminants, or

                                      -29-
<PAGE>

hazardous, extremely hazardous, or toxic materials, substances,
chemicals or wastes now or hereafter located on the Frisco City Properties; (ii)
all obligations and liabilities arising from or in connection with any gas
production, pipeline, storage, processing or other imbalance attributable to
substances produced from the Frisco City Properties on or after the Effective
Time; and (iii) all other costs, obligations and liabilities that relate to the
Frisco City Properties and, in each case, arise from or relate to events
occurring on or after the Effective Time.

     (c) All such plugging, replugging, abandonment, removal, disposal, and
restoration operations shall be in compliance with applicable laws and
regulations and contracts, and shall be conducted in a good and workmanlike
manner.

                                   ARTICLE 14
                                  MISCELLANEOUS

     14.1 Fees and Taxes. Except as otherwise specifically provided, all fees,
costs and expense incurred by CECI, P&L LP and P&L Inc. in negotiating this
Agreement or in consummating the transactions contemplated by this Agreement
shall be paid by the Party incurring the same, including, without limitation,
legal and accounting fees, costs and expenses. All required documentary, filing
and recording fees for the assignments, conveyance or other instruments required
to convey title to the a property being conveyed hereunder shall be borne by the
acquiring Party. In addition, the liability for any sales, use, transfer or
similar tax associated with the sale and/or transfer of a property being
conveyed hereunder shall be the liability of, and for the account of, the
acquiring Party and such liability shall not be subject to proration as provided
in Sections 2.2 or 2.3.

     14.2 Notices. All notices and communications required or permitted under
this Agreement shall be in writing and shall be deemed to have been duly made
when actually delivered, including delivery by courier, facsimile, telecopy, or
other electronic medium, or if mailed by registered to certified mail, postage
prepaid, addressed as follows:

CECI:

CASTLE EXPLORATION COMPANY, INC.
One Radnor Corporate Center, Suite 250
100 Matsonford Road
Radnor, Pennsylvania  19087
Attn: Richard E. Staedtler
Chief Financial Officer
Telephone: (610) 995-9400
Facsimile: (610) 995-0409


                                      -30-
<PAGE>

P&L LP

PARKS & LUTTRELL ENERGY PARTNERS, L.P.
c/o  Parks & Luttrell Resources, LLC as General Partner
Suite 1328
1221 Lamar
Houston, Texas 77010
Attn: J. W. Parks, III
Executive Vice President
Telephone: (713) 658-1947
Facsimile: (713) 658-1950

BUYER:

PARKS & LUTTRELL ENERGY, INC.
Suite 1328
1221 Lamar
Houston, Texas 77010
Attn: J. W. Parks, III
President
Telephone: (713) 658-1947
Facsimile: (713) 658-1950

     Either Party may, by written notice so delivered to the other, change the
address to which delivery shall thereafter be made.

     14.3 Amendments. This Agreement may not be amended except by an instrument
in writing signed by CECI, P&L LP and P&L Inc..

     14.4 Preparation of Agreement. CECI, P&L LP and P&L Inc. and their
respective counsel participated in the preparation of this Agreement. In the
event of any ambiguity in this Agreement, no presumption shall arise based on
the identity of the draftsman of this Agreement.

     14.5 Headings. The headings of the articles and sections of this Agreement
are for guidance and convenience of reference only and shall not limit or
otherwise affect any of the terms or provisions of this Agreement.

     14.6 Counterparts. This Agreement may be executed by CECI, P&L LP and P&L
Inc. in any number of counterparts, each of which shall be deemed an original
instrument, but all of which together shall constitute but one and the same
instrument.

     14.7 References. References made in this Agreement, including use of a
pronoun, shall be deemed to include, where applicable, masculine, feminine,
singular or plural, individuals or

                                      -31-
<PAGE>

corporations. As used in this Agreement, "person" shall mean any natural person,
corporation, partnership, trust, estate or other entity.

     14.8 Governing Law. This Agreement and the transactions contemplated hereby
shall be construed in accordance with, and governed by, the laws of the State of
Texas without giving effect to the conflicts of law rules thereof. Any disputes
concerning this Agreement or the subject matter hereof shall be brought in a
court of competent jurisdiction of the State of Texas.

     14.9 Entire Agreement. This Agreement (including the Exhibits hereto)
constitutes the entire understanding between the Parties with respect to the
subject matter hereof, superseding all negotiations, prior discussions and prior
agreements and understanding relating to such subject matter.

     14.10 Assignment; Parties in Interest. No Party shall assign this Agreement
without the other Party's prior written consent; provided, however, that this
requirement shall not apply to a subsidiary or other affiliate of the assigning
Party so long as the assigning Party remains responsible for its assignee's
obligations hereunder. Subject to the foregoing, this Agreement shall be binding
upon, and shall inure to the benefit of, the Parties and their respective
successors and assigns.

     14.11 Further Cooperation. After the Closing, CECI, P&L LP and P&L Inc.
shall execute and deliver, or shall caused to be executed and delivered from
time to time, such further instruments of conveyance and transfer and shall take
such other action as any Party may reasonably request to convey and deliver the
Britt Ranch Properties to P&L LP and the Frisco City Properties to CECI, to
accomplish the orderly transfer of the Britt Ranch Properties to P&L LP and the
Frisco City Properties to CECI, or to otherwise effectuate the transactions
contemplated by this Agreement. If either Party hereto receives monies belonging
to the other, such amount shall immediately be paid over to the proper Party. If
an invoice or other evidence of an obligation is received by a Party, which is
partially an obligation of both the selling and buying Party hereunder, then the
Parties shall consult with each other and each shall promptly pay its portion of
such obligation to the obligee.

     14.12 Press Release. No Party shall make any press release or other
announcement in connection with the execution of this Agreement or the Closing
without first consulting with the other Party. Following such consultation and
good faith attempt to make reasonable accommodations, either Party may make any
announcement or press release that it believes is either required by applicable
law or the rules of any stock exchange, or is advisable in connection with such
Party's obligation to provide public disclosure regarding its activities. This
provision shall not apply to any filing with any governmental body or stock
exchange required by law, rule or regulation.

     14.13 Subrogation. P&L LP shall be subrogated to all rights, actions and
warranties that CECI may have with respect to CECI's predecessors-in-interest as
to the Britt Ranch Properties and CECI shall be subrogated to all rights,
actions and warranties that P&L Inc. may have with respect to P&L Inc.'s
predecessors-in-interest as to the Frisco City Properties.

                                      -32-
<PAGE>


EXECUTED as of the date first above stated, but made effective as of the
Effective Time.

                                       CECI:

                                       CASTLE EXPLORATION COMPANY, INC.


                                       By /s/ Timothy M. Murin
                                          -------------------------------------
                                          Timothy M. Murin
                                          President


                                       P&L LP:

                                       PARKS & LUTTRELL ENERGY PARTNERS, L.P.

                                       By Parks & Luttrell Resources,
                                          LLC acting as General Partner
                                          of Parks & Luttrell Energy
                                          Partners, L.P.



                                       By /s/ J. W. Parks, III
                                          --------------------------------------
                                          J. W. Parks, III
                                          Executive Vice President


                                       P&L Inc.:

                                       PARKS & LUTTRELL ENERGY, INC.


                                       By /s/ J. W. Parks, III
                                          --------------------------------------
                                          J. W. Parks, III
                                          President



                                      -33-