<PAGE>
                                                                    EXHIBIT 10.8

                  THIRD AMENDMENT TO CANADIAN CREDIT AGREEMENT


         THIS THIRD AMENDMENT TO CANADIAN CREDIT AGREEMENT (herein called this
"Amendment") made as of July 31, 2001 by and among Northstar Energy Corporation,
an Alberta corporation ("Canadian Borrower"), Bank of America Canada,
individually and as administrative agent ("Canadian Agent"), and the Canadian
Lenders party to the Original Agreement defined below ("Canadian Lenders").

                                   WITNESSETH:

         WHEREAS, Canadian Borrowers, Canadian Agent and Canadian Lenders
entered into that certain Canadian Credit Agreement dated as of August 29, 2000
(as amended, supplemented, or restated to the date hereof, the "Original
Agreement"), for the purpose and consideration therein expressed, whereby
Canadian Lenders became obligated to make loans to Canadian Borrowers as therein
provided;

         WHEREAS, on January 1, 2001 Northstar Energy, Devon Energy Canada
Holding Corporation (the successor by amalgamation to Devon Energy Canada) and
certain other Alberta corporations, all of which were Subsidiaries of US
Borrower, amalgamated under the name Northstar Energy Corporation (defined above
as the "Canadian Borrower") which is now the sole Canadian Borrower;

         WHEREAS, Canadian Borrower, Canadian Agent and Canadian Lenders desire
to amend the Original Agreement as set forth herein;

         NOW, THEREFORE, in consideration of the premises and the mutual
covenants and agreements contained herein and in the Original Agreement, in
consideration of the loans which may hereafter be made by Canadian Lenders to
Canadian Borrower, and for other good and valuable consideration, the receipt
and sufficiency of which are hereby acknowledged, the parties hereto do hereby
agree as follows:

                                   ARTICLE I.

                           Definitions and References

         Section 1.1. Terms Defined in the Original Agreement. Unless the
context otherwise requires or unless otherwise expressly defined herein, the
terms defined in the Original Agreement shall have the same meanings whenever
used in this Amendment.

         Section 1.2. Other Defined Terms. Unless the context otherwise
requires, the following terms when used in this Amendment shall have the
meanings assigned to them in this Section 1.2.



                                    Third Amendment to Canadian Credit Agreement
<PAGE>

                  "Amendment" means this Third Amendment to Canadian Credit
         Agreement.

                  "Canadian Agreement" means the Original Agreement as amended
         hereby.

                                   ARTICLE II.

                        Amendments to Original Agreement

         Section 2.1. Defined Terms.

         (a) The definition of "ERISA Plan" in Annex I of the Original Agreement
is hereby amended in its entirety to read as follows:

                  "'ERISA Plan' means any employee pension benefit plan (other
         than a Multiemployer Plan) subject to Title IV of ERISA maintained by
         any ERISA Affiliate with respect to which any Restricted Person has a
         fixed or contingent liability."

         (b) The definition of "Permitted Liens" in Annex I of the Original
Agreement is hereby amended by deleting subsection (w) thereof and adding the
following new subsections (w) and (x) in lieu thereof:

                  "(w) Liens on Margin Stock.

                  (x) in addition to Liens permitted by clauses (a) through (w)
         above, Liens on property or assets if the aggregate Indebtedness
         secured thereby does not exceed US $50,000,000."

         (c) The definition of "Stamping Fee Rate" in Annex I of the Original
Agreement is hereby amended in its entirety to read as follows:

                  "`Stamping Fee Rate' means with respect to any Bankers'
         Acceptance accepted by any Canadian Resident Lender at any time, the
         Applicable Margin then in effect.

         (d) The definition of "Termination Event" in Annex I of the Original
Agreement is hereby amended in its entirety to read as follows:

                  "'Termination Event' means (a) the occurrence with respect to
         any ERISA Plan of (i) a reportable event described in Sections
         4043(c)(5) or (6) of ERISA or (ii) any other reportable event described
         in Section 4043(c) of ERISA other than a reportable event not subject
         to the provision for 30-day notice to the Pension Benefit Guaranty
         Corporation pursuant to a waiver by such corporation under Section
         4043(a) of ERISA; or (b) the withdrawal of any ERISA Affiliate from an
         ERISA Plan during a plan year in which it was



                                       2


                                    Third Amendment to Canadian Credit Agreement
<PAGE>

         a "substantial employer" as defined in Section 4001(a)(2) of ERISA; or
         (c) a complete or partial withdrawal by any ERISA Affiliate from a
         Multiemployer Plan or notification that a Multiemployer Plan is in
         reorganization; or (d) the filing of a notice of intent to terminate
         any ERISA Plan or Multiemployer Plan or the treatment of any ERISA Plan
         amendment or Multiemployer Plan amendment as a termination under
         Section 4041 or 4041A of ERISA; or (e) the institution of proceedings
         to terminate any ERISA Plan or Multiemployer Plan by the Pension
         Benefit Guaranty Corporation under Section 4042 of ERISA; or (f) any
         other event or condition which might constitute grounds under Section
         4042 of ERISA for the termination of, or the appointment of a trustee
         to administer, any ERISA Plan or Multiemployer Plan."

         (e) The definition of "Total Capitalization" in Annex I of the Original
Agreement is hereby amended in its entirety to read as follows:

                  "'Total Capitalization' means the sum (without duplication) of
         (i) US Borrower's Consolidated Total Funded Debt plus (ii) US
         Borrower's Consolidated shareholder's equity plus (iii) 60% of the
         outstanding balance of the Devon Trust Securities. Total Capitalization
         shall be calculated excluding non-cash write-downs and related charges
         which are required under Rule 4-10 (Financial Accounting and Reporting
         for Oil and Gas Producing Activities Pursuant to the Federal Securities
         Laws and the Energy Policy and Conservation Act of 1975) of Regulation
         S-X promulgated by Securities and Exchange Commission Regulation, or by
         US GAAP."

         (f) The first sentence of the definition of "Unrestricted Subsidiary"
in Annex I of the Original Agreement is hereby amended in its entirety to read
as follows (it being understood that the last sentence thereof and the list of
Unrestricted Subsidiaries set forth therein are not being modified by this
Amendment):

                  "'Unrestricted Subsidiary' means any corporation, association,
         partnership, limited liability company, joint venture, or other
         business or corporate entity, enterprise or organization (i) which is
         listed below in this definition, or (ii) in which US Borrower did not
         own an interest (directly or indirectly) as of August 29, 2000, which
         thereafter became a Subsidiary of US Borrower and which, within 90 days
         after becoming a Subsidiary of US Borrower, is designated as an
         Unrestricted Subsidiary by US Borrower to US Agent; provided that in
         the event any such Subsidiary becomes a Material Subsidiary at any
         time, such Subsidiary shall cease to be an Unrestricted Subsidiary at
         such time and shall automatically become a Restricted Subsidiary."

         (g) The following defined terms are hereby added to Annex I of the
Original Agreement in alphabetical order:

                  "'Disclosure Report' means a written notice given by US
         Borrower to all Lender Parties or a certificate given by the Senior
         Vice President-Finance or the Treasurer of US Borrower under Sections
         6.2(a) and (b)."



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                                    Third Amendment to Canadian Credit Agreement
<PAGE>

                  "'Multiemployer Plan' means a multiemployer plan within the
         meaning of Section 4001(a)(3) of ERISA to which any ERISA Affiliate is
         making or is obligated to make contributions or, during the five
         preceding plan years, has made or has been obligated to make
         contributions."

                  "'Margin Stock' means 'margin stock' as defined in Reg U."

                  "'Material Subsidiary' means a Subsidiary of US Borrower which
         owns assets having a book value that exceeds ten percent (10%) of the
         book value of US Borrower's Consolidated assets."

                  "'Reg U' means Regulation U promulgated by the Board of
         Governors of the Federal Reserve System."

         Section 2.2. Default Rate. Section 1.5(a)(vi) of the Original Agreement
is hereby amended in its entirety to read as follows:

                  "(vi) All past due principal of and past due interest on the
         Canadian Loans shall bear interest on each day outstanding at the
         applicable Default Rate in effect on such day, and such interest shall
         be due and payable daily as it accrues."

         Section 2.3. Use of Proceeds. Section 1.10 of the Original Agreement is
hereby amended in its entirety to read as follows:

                  "Section 1.10. Use of Proceeds. Canadian Borrower shall use
         all Canadian Advances and Canadian Swing Loans made under this
         Agreement to refinance existing indebtedness (including any commercial
         paper issued by or for the account of Canadian Borrower), to finance
         capital expenditures, to refinance Matured Canadian LC Obligations
         outstanding under this Agreement, and to provide working capital for
         its operations and for other general business purposes. Canadian
         Borrower shall use all Letters of Credit for its general corporate
         purposes. If any Canadian Advance or Canadian Swing Loan is used for a
         purpose which is governed by Reg U, Canadian Borrower shall comply with
         Reg U in all respects. Canadian Borrower represents and warrants that
         Canadian Borrower is not engaged principally, or as one of Canadian
         Borrower's important activities, in the business of extending credit to
         others for the purpose of purchasing or carrying Margin Stock."

         Section 2.4. Conditions Precedent. Section 4.3(c) of the Original
Agreement is hereby deleted.

         Section 2.5. Representations and Warranties; Litigation. Sections 5.2
and 5.7 of the Original Agreement are hereby amended in their entirety to read
as follows:

                  "Section 5.2 Organization and Good Standing. Each of Canadian
         Borrower and the



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                                    Third Amendment to Canadian Credit Agreement
<PAGE>

         Material Subsidiaries of Canadian Borrower is duly organized, validly
         existing and in good standing under the Laws of its jurisdiction of
         organization, having all powers required to carry on its business and
         enter into and carry out the transactions contemplated hereby. Each of
         Canadian Borrower and the Material Subsidiaries of Canadian Borrower is
         duly qualified, in good standing, and authorized to do business in all
         other jurisdictions within Canada wherein the character of the
         properties owned or held by it or the nature of the business transacted
         by it makes such qualification necessary except where failure to so
         qualify would not have a Material Adverse Effect. Each of Canadian
         Borrower and the Material Subsidiaries of Canadian Borrower has taken
         all actions and procedures customarily taken in order to enter, for the
         purpose of conducting business or owning property, each jurisdiction
         outside Canada wherein the character of the properties owned or held by
         it or the nature of the business transacted by it makes such actions
         and procedures desirable except where failure to so qualify would not
         have a Material Adverse Effect.

                  Section 5.7. Litigation. Except as disclosed in the Initial
         Financial Statements, in the financial statements delivered to each
         Lender Party pursuant to Section 6.2, in the Disclosure Schedule or in
         a Disclosure Report, there are no actions, suits or legal, equitable,
         arbitrative or administrative proceedings pending, or to the knowledge
         of Canadian Borrower threatened, against Canadian Borrower or any
         Subsidiary of Canadian Borrower that is a Restricted Person before any
         Tribunal which would reasonably be expected to have a Material Adverse
         Effect, and there are no outstanding judgments, injunctions, writs,
         rulings or orders by any such Tribunal against any such Person which
         would reasonably be expected to have a Material Adverse Effect."

         Section 2.6. Representations and Warranties; Names and Places of
Business. Section 5.9 of the Original Agreement is hereby deleted in its
entirety.

         Section 2.7. Representations and Warranties; Canadian Borrower's
Subsidiaries; Title to Properties; Licenses. Sections 5.10 and 5.11 of the
Original Agreement are hereby amended in their entirety to read as follows:

                  "Section 5.10. Canadian Borrower's Subsidiaries. Canadian
         Borrower does not presently have any Material Subsidiary except those
         listed in the Disclosure Schedule or in a Disclosure Report (it being
         understood that inclusion of a Subsidiary on the Disclosure Schedule
         does not mean that such Subsidiary is a Material Subsidiary). Canadian
         Borrower owns, directly or indirectly, the equity interest in each of
         its Material Subsidiaries which is indicated in the Disclosure Schedule
         or in a Disclosure Report.

                  Section 5.11. Title to Properties; Licenses. Canadian Borrower
         and each Subsidiary of Canadian Borrower that is a Restricted Person
         has good and defensible title to all of its material properties and
         assets, free and clear of all Liens other than Permitted Liens and of
         all impediments to the use of such properties and assets in such
         Restricted Person's business except to the extent failure to have such
         title would not have a Material Adverse Effect. Canadian Borrower and
         each Subsidiary of Canadian Borrower that is a



                                       5


                                    Third Amendment to Canadian Credit Agreement
<PAGE>

         Restricted Person possesses all licenses, permits, franchises, patents,
         copyrights, trademarks and trade names, and other intellectual property
         (or otherwise possesses the right to use such intellectual property)
         which are necessary to carry out its business as presently conducted
         and as presently proposed to be conducted hereafter except to the
         extent failure to possess such licenses, permits, franchises, and
         intellectual property would not have a Material Adverse Effect, and no
         such Restricted Person is in violation in any material respect of the
         terms under which it possesses such intellectual property or the right
         to use such intellectual property except to the extent any such
         violation would not have a Material Adverse Effect."

         Section 2.8. Notice of Material Events and Change of Address. Section
6.4 of the Original Agreement is hereby amended to replace all references
therein to the amount of "$100,000,000" to "$125,000,000", to delete the last
sentence of such section, and to amend clause (d) thereof in its entirety to
read as follows:

                  "(d) the occurrence of any Termination Event which could
         reasonably be expected to cause (i) the total amount of withdrawal
         liability that would be incurred by all ERISA Affiliates upon their
         complete withdrawal from all Multiemployer Plans to exceed US
         $125,000,000, or (ii) the aggregate Liabilities of the ERISA Affiliates
         to ERISA Plans to exceed $125,000,000."

         Section 2.9. Environmental Matters. Section 6.12(b) of the Original
Agreement is hereby amended to replace the reference therein to the amount of
"$100,000,000" to "$125,000,000."

         Section 2.10. Indebtedness. Subsections (b) and (l) of Section 7.1 of
the Original Agreement are hereby amended in their entirety to read as follows:

                  "(b) capital lease obligations (excluding oil, gas or mineral
         leases) entered into in the ordinary course of such Restricted Person's
         business in arm's length transactions at competitive market rates under
         competitive terms and conditions in all respects, provided that such
         capital lease obligations required to be paid in any Fiscal Year do not
         in the aggregate exceed US $50,000,000 for all Restricted Subsidiaries,
         whether or not Subsidiaries of Canadian Borrower.

                  (l) miscellaneous items of Indebtedness of all Restricted
         Persons (other than US Borrower) not described in subsections (a)
         through (k) which do not in the aggregate exceed US $400,000,000 in
         principal amount at any one time outstanding."

         Section 2.11. Limitation on Restricted Payments. Section 7.5 of the
Original Agreement is hereby deleted.

         Section 2.12. Events of Default. Subsection (c) and (e) of Section 8.1
of the Original Agreement are hereby amended in their entirety to read as
follows:



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                                    Third Amendment to Canadian Credit Agreement
<PAGE>

                  "(c) Any Restricted Person fails (other than as referred to in
         subsections (a) or (b) above) to (i) duly comply with Section 1.10 or
         Section 7.4(b) of the Canadian Agreement or (ii) duly observe, perform
         or comply with any other covenant, agreement, condition or provision of
         any Canadian Loan Document, and such failure remains unremedied for a
         period of thirty (30) days after notice of such failure is given by
         Canadian Agent to Canadian Borrower;

                  (e) Any Restricted Person fails to duly pay any Indebtedness
         in excess of US $125,000,000 constituting principal or interest owed by
         it with respect to borrowed money or money otherwise owed under any
         note, bond, or similar instrument, or (ii) breaches or defaults in the
         performance of any agreement or instrument by which any such
         Indebtedness is issued, evidenced, governed, or secured, other than a
         breach or default described in clause (i) above, and any such failure,
         breach or default results in the acceleration of such Indebtedness;
         provided that notwithstanding any provision of this subsection (e) to
         the contrary, to the extent that the terms of any such agreement or
         instrument governing the sale, pledge or disposal of Margin Stock or
         utilization of the proceeds of such Indebtedness in connection
         therewith would result in such acceleration and in a Default or an
         Event of Default under this Agreement, and would cause this Agreement
         or any Canadian Loan to be subject to the margin requirements or any
         other restriction under Reg U, then such acceleration shall not
         constitute a Default or Event of Default under this subsection (e);"

         Section 2.13. Additional Events of Default. Section 8.1(h) is hereby
amended by replacing all references therein to the amount of "$100,000,000" to
"$125,000,000."

         Section 2.14. Amendments to Statutes and Regulations. Section 10.18 of
the Original Agreement is hereby amended by adding the following sentence at the
end thereof:

                  "Unless the context otherwise requires or unless otherwise
         provided herein, the references in this Agreement to a particular
         statute, rule or regulation also refer to and include all amendments,
         supplements and other modifications to such statute, rule or
         regulation."

         Section 2.15. Disclosure Schedule. Paragraph 6 of the Disclosure
Schedule to the Original Agreement is hereby amended by adding the name of the
following Subsidiary thereto:

                  Canadian Mustang Energy Inc.

         Section 2.16. Canadian Notes. Each Canadian Note (and the form of
Canadian Note attached as Exhibit A-1 to the Original Agreement) are hereby
amended by deleting the proviso at the end of the first sentence of the fourth
paragraph thereof which reads as follows: "; provided that if an Event of
Default has occurred and is continuing, Canadian Base Rate Loans shall bear
interest on each day outstanding at the applicable Default Rate in effect on
such day". Each Canadian Note (and the form of Canadian Note attached as Exhibit
A-1 to the Original Agreement) are hereby further amended by deleting the
proviso at the end of the third sentence of the fourth paragraph



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                                    Third Amendment to Canadian Credit Agreement
<PAGE>

thereof which reads as follows: "; provided that if an Event of Default has
occurred and is continuing, Canadian Prime Rate Loans shall bear interest on
each day outstanding at the applicable Default Rate in effect on such day." Each
Canadian Note (and the form of Canadian Note attached as Exhibit A-1 to the
Original Agreement) are hereby further amended by deleting the proviso at the
end of the fifth sentence of the fourth paragraph thereof which reads as
follows: "; provided that if an Event of Default has occurred and is continuing,
such US Dollar Eurodollar Loan shall bear interest on each day outstanding at
the applicable Default Rate in effect on such day." Each Canadian Note (and the
form of Canadian Note attached as Exhibit A-1 to the Original Agreement) are
hereby further amended by deleting the proviso at the end of the seventh
sentence of the fourth paragraph thereof which reads as follows: "; provided
that if an Event of Default has occurred and is continuing, such Canadian Dollar
Eurodollar Loan shall bear interest on each day outstanding at the applicable
Default Rate in effect on such day."

         Section 2.17. Canadian Swing Note. The Canadian Swing Note (and the
form of Canadian Swing Note attached as Exhibit A-2 to the Original Agreement)
are hereby amended by deleting the proviso at the end of the first sentence of
the fourth paragraph thereof which reads as follows: "; provided that if an
Event of Default has occurred and is continuing, Canadian Swing Loans shall bear
interest on each day outstanding at the applicable Default Rate in effect on
such day."

         Section 2.18. Competitive Bid Notes. Each Competitive Bid Note issued
under the Canadian Agreement (and the form of Competitive Bid Note attached as
Exhibit M to the Original Agreement) are hereby amended by deleting the proviso
at the end of the first sentence of the fifth paragraph thereof which reads as
follows: "; provided that if an Event of Default has occurred and is continuing,
such Competitive Bid Loan shall bear interest on each day outstanding at the
applicable Default Rate in effect on such day."

                                  ARTICLE III.

                           Conditions of Effectiveness

         Section 3.1. Effective Date. This Amendment shall become effective as
of the date first above written when and only when:

         (a) Canadian Agent shall have received all of the following, at
Canadian Agent's office, duly executed and delivered and in form and substance
satisfactory to Canadian Agent, all of the following:

                  (i) this Amendment executed by Canadian Borrower, Canadian
         Agent and Canadian Required Lenders; provided that the amendment set
         forth in Section 2.2 hereof, insofar as it applies to the Canadian
         Notes, and in Section 2.16 hereof shall become effective only when
         executed and delivered by all Canadian Lenders, the amendment set forth
         in Section 2.3 hereof, insofar as it applies to the Canadian Swing
         Note, and in Section 2.17 hereof shall become effective only when
         executed and delivered by the Canadian Swing Lender, and the amendment
         set forth in Section 2.3 hereof, insofar as it



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                                    Third Amendment to Canadian Credit Agreement
<PAGE>

         applies to any Competitive Bid Note, and in Section 2.18 hereof shall
         become effective only when executed and delivered by the holder of such
         Competitive Bid Note; and provided further that the amendment set forth
         in Section 2.4 of this Amendment shall become effective only when
         executed and delivered by all Canadian Lenders.

                  (ii) a certificate of the Chairman of the Board, President, or
         Vice President - Finance of Canadian Borrower dated the date of this
         Amendment certifying: (i) that all of the representations and
         warranties set forth in Article IV hereof are true and correct at and
         as of such date, and (ii) that no Default exists at and as of such
         date.

         (b) Canadian Borrower shall have paid, in connection with such Canadian
Loan Documents, all fees and reimbursements to be paid to Canadian Agent
pursuant to any Canadian Loan Documents, or otherwise due Canadian Agent and
including fees and disbursements of Canadian Agent's attorneys.

                                   ARTICLE IV.

                         Representations and Warranties

         Section 4.1. Representations and Warranties of Canadian Borrower. In
order to induce each Canadian Lender to enter into this Amendment, Canadian
Borrower represents and warrants to each Canadian Lender that:

         (a) The representations and warranties contained in Article V of the
Original Agreement are true and correct at and as of the time of the
effectiveness hereof, except to the extent that the facts on which such
representations and warranties are based have been changed by the extension of
credit under the Canadian Agreement.

         (b) Canadian Borrower is duly authorized to execute and deliver this
Amendment and is and will continue to be duly authorized to borrow monies and to
perform its obligations under the Canadian Agreement. Canadian Borrower has duly
taken all corporate action necessary to authorize the execution and delivery of
this Amendment and to authorize the performance of the obligations of Canadian
Borrower hereunder.

         (c) The execution and delivery by Canadian Borrower of this Amendment,
the performance by Canadian Borrower of its obligations hereunder and the
consummation of the transactions contemplated hereby do not and will not (i)
conflict with any provision of (A) any Law, (B) the organizational documents of
Canadian Borrower, or (C) any agreement, judgment, license, order or permit
applicable to or binding upon Canadian Borrower unless such conflict would not
reasonably be expected to have a Material Adverse Effect, or (ii) result in or
require the creation of any Lien upon any assets or properties of Canadian
Borrower which would reasonably be expected to have a Material Adverse Effect,
except as expressly contemplated or permitted in the Loan Documents. Except as
expressly contemplated in the Loan Documents no consent, approval, authorization
or order of, and no notice to or filing with, any Tribunal or third party is
required in connection with the execution, delivery or performance by Canadian
Borrower



                                       9
<PAGE>

of this Amendment or to consummate any transactions contemplated by this
Amendment, unless failure to obtain such consent would not reasonably be
expected to have a Material Adverse Effect.

         (d) When duly executed and delivered, each of this Amendment and the
Canadian Agreement will be a legal and binding obligation of Canadian Borrower,
enforceable in accordance with its terms, except as limited by bankruptcy,
insolvency or similar laws of general application relating to the enforcement of
creditors' rights and by equitable principles of general application.

         (e) The audited annual Consolidated financial statements of US Borrower
dated as of December 31, 2000 and the unaudited quarterly Consolidated financial
statements of US Borrower dated as of March 31, 2001 fairly present the
Consolidated financial position at such dates and the Consolidated statement of
operations and the changes in Consolidated financial position for the periods
ending on such dates for US Borrower. Copies of such financial statements have
heretofore been delivered to each Canadian Lender. Since such dates no material
adverse change has occurred in the Consolidated financial condition or
businesses of US Borrower.

                                   ARTICLE V.

                                  Miscellaneous

         Section 5.1. Ratification of Agreements. The Original Agreement and the
Canadian Notes as hereby amended are hereby ratified and confirmed in all
respects. The Canadian Loan Documents, as they may be amended or affected by
this Amendment, are hereby ratified and confirmed in all respects. Any reference
to the Canadian Agreement in any Loan Document shall be deemed to be a reference
to the Original Agreement as hereby amended. The execution, delivery and
effectiveness of this Amendment shall not, except as expressly provided herein,
operate as a waiver of any right, power or remedy of Canadian Lenders under the
Canadian Agreement or any other Canadian Loan Document nor constitute a waiver
of any provision of the Canadian Agreement or any other Canadian Loan Document.

         Section 5.2. Survival of Agreements. All representations, warranties,
covenants and agreements of Canadian Borrower herein shall survive the execution
and delivery of this Amendment and the performance hereof, including without
limitation the making or granting of the Loans, and shall further survive until
all of the Obligations are paid in full. All statements and agreements contained
in any certificate or instrument delivered by Canadian Borrower or any
Restricted Person hereunder or under the Canadian Agreement to any Canadian
Lender shall be deemed to constitute representations and warranties by, and/or
agreements and covenants of, Canadian Borrower under this Amendment and under
the Canadian Agreement.



                                       10


                                    Third Amendment to Canadian Credit Agreement
<PAGE>

         Section 5.3. Canadian Loan Documents. This Amendment is a Canadian Loan
Document, and all provisions in the Canadian Agreement pertaining to Canadian
Loan Documents apply hereto.

         Section 5.4. Governing Law. This Amendment shall be governed by and
construed in accordance the laws of the Province of Alberta and any applicable
laws of Canada in all respects, including construction, validity and
performance.

         Section 5.5. Counterparts; Fax. This Amendment may be separately
executed in counterparts and by the different parties hereto in separate
counterparts, each of which when so executed shall be deemed to constitute one
and the same Amendment. This Amendment may be validly executed by facsimile or
other electronic transmission.

         THIS AMENDMENT AND THE OTHER CANADIAN LOAN DOCUMENTS REPRESENT THE
FINAL AGREEMENT BETWEEN THE PARTIES AND MAY NOT BE CONTRADICTED BY EVIDENCE OF
PRIOR, CONTEMPORANEOUS, OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES. THERE ARE
NO UNWRITTEN ORAL AGREEMENTS OF THE PARTIES.


         IN WITNESS WHEREOF, this Amendment is executed as of the date first
above written.



                                NORTHSTAR ENERGY CORPORATION
                                Canadian Borrower

                                By: /s/ John Richels
                                    --------------------------------------------
                                    Name:    John Richels
                                    Title:   President & Chief Executive Officer





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                                    Third Amendment to Canadian Credit Agreement
<PAGE>

                                BANK OF AMERICA CANADA
                                Administrative Agent, Canadian LC Issuer and
                                Lender

                                By:      /s/ Donald R. Chung
                                         ---------------------------------------
                                         Name: Donald R. Chung
                                         Title: Vice President
                                                Corporate Investment Banking

                                BANK ONE, NA CANADA BRANCH
                                Lender

                                By:      /s/ Ronald L. Dierker
                                         ---------------------------------------
                                         Name: Ronald L. Dierker
                                         Title: Director, Capital Markets

                                THE CHASE MANHATTAN BANK, TORONTO BRANCH
                                Lender

                                By:      /s/ Drew McDonald
                                         ---------------------------------------
                                         Name: Drew McDonald
                                         Title: Authorized Representative

                                By:      /s/ Ralph Kern
                                         ---------------------------------------
                                         Name: Ralph Kern
                                         Title: Authorized Representative

                                UMB BANK
                                Lender

                                By:      /s/ Richard J. Lehrter
                                         ---------------------------------------
                                         Name: Richard J. Lehrter
                                         Title: Community Bank President

                                FIRST UNION NATIONAL BANK
                                Lender

                                By:      /s/ David Humphreys
                                         ---------------------------------------
                                         Name: David Humphreys
                                         Title: Vice President




                                    Third Amendment to Canadian Credit Agreement
<PAGE>

                                WESTDEUTSCHE LANDESBANK GIROZENTRALE
                                Lender

                                By:      /s/ Salvatore Battinelli
                                         ---------------------------------------
                                         Name: Salvatore Battinelli
                                         Title: Managing Director, Credit Dept.

                                By:      /s/ Water T. Duffy III
                                         ---------------------------------------
                                         Name: Walter T. Duffy III
                                         Title: Associate Director

                                THE BANK OF NEW YORK
                                Lender

                                By:      /s/ Raymond J. Palmer
                                         ---------------------------------------
                                         Name: Raymond J. Palmer
                                         Title: Vice President

                                ROYAL BANK OF CANADA
                                Lender

                                By:      /s/ Tom J. Oberaigner
                                         ---------------------------------------
                                         Name: Tom J. Oberaigner
                                         Title: Senior Manager

                                SUNTRUST BANK, ATLANTA
                                Lender

                                By:      /s/ David J. Edge
                                         ---------------------------------------
                                         Name: David J. Edge
                                         Title: Director

                                THE CHASE MANHATTAN BANK, TORONTO BRANCH
                                Lender

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



                                    Third Amendment to Canadian Credit Agreement
<PAGE>

                                CITIBANK CANADA
                                Lender

                                By:      /s/ James K. G. Campbell
                                         ---------------------------------------
                                         Name: James K. G. Campbell
                                         Title: Vice President

                                DEUTSCHE BANK AG NEW YORK BRANCH AND/OR CAYMAN
                                ISLANDS BRANCH
                                Lender

                                By:      /s/ Michael E. Keating
                                         ---------------------------------------
                                         Name: Michael E. Keating
                                         Title: Managing Director

                                By:      /s/ Joel Makowsky
                                         ---------------------------------------
                                         Name: Joel Makowsky
                                         Title: Vice President

                                CANADIAN IMPERIAL BANK OF COMMERCE
                                Lender

                                By:      /s/ Joelle Schellenberg
                                         ---------------------------------------
                                         Name: Joelle Schellenberg
                                         Title: Director

                                By:      /s/ David W. Richardson
                                         ---------------------------------------
                                         Name: David W. Richardson
                                         Title: Vice President

                                ABN AMRO BANK CANADA
                                Lender

                                By:      /s/ Mark Bohn
                                         ---------------------------------------
                                         Name: Mark Bohn
                                         Title: Group Vice President

                                By:      /s/ Teresa Wu
                                         ---------------------------------------
                                         Name: Teresa Wu
                                         Title: Vice President



                                    Third Amendment to Canadian Credit Agreement
<PAGE>

                                BAYERISCHE LANDESBANK GIROZENTRALE,
                                CAYMAN ISLANDS BRANCH
                                Lender

                                By:      /s/ Hereward Drummond
                                         ---------------------------------------
                                         Name: Hereward Drummond
                                         Title: Senior Vice President

                                By:      /s/ James H. Boyle
                                         ---------------------------------------
                                         Name: James H. Boyle
                                         Title: Vice President

                                THE FUJI BANK, LIMITED
                                Lender

                                By:      /s/ Jacques Azagury
                                         ---------------------------------------
                                         Name: Jacques Azagury
                                         Title: Senior Vice President & Manager

                                CREDIT LYONNAIS NEW YORK BRANCH
                                Lender

                                By:      /s/ Jacues Busquet
                                         ---------------------------------------
                                         Name: Jacques Busquet
                                         Title: Executive Vice President

                                BANK OF TOKYO - MITSUBISHI (CANADA)
                                Lender

                                By:      /s/ Davis J. Stewart
                                         ---------------------------------------
                                         Name: Davis J. Stewart
                                         Title: Vice President



                                    Third Amendment to Canadian Credit Agreement
<PAGE>

                                                                 Third Amendment


                              CONSENT AND AGREEMENT


         Devon Energy Corporation, a Delaware corporation ("Canadian
Guarantor"), hereby (i) consents to the provisions of this Amendment and the
transactions contemplated herein, (ii) ratifies and confirms the Guaranty dated
as of August 29, 2000 made by it for the benefit of Canadian Agent and Lenders
executed pursuant to the Credit Agreement and the other Canadian Loan Documents,
(iii) agrees that all of its respective obligations and covenants thereunder
shall remain unimpaired by the execution and delivery of this Amendment and the
other documents and instruments executed in connection herewith, and (iv) agrees
that the Canadian Guaranty and such other Canadian Loan Documents shall remain
in full force and effect.



                                        DEVON ENERGY CORPORATION



                                        By:  /s/ William T. Vaughn
                                             -----------------------------------
                                             Name: William T. Vaughn
                                             Title: Senior Vice President -
                                                    Finance



                                    Third Amendment to Canadian Credit Agreement


<PAGE>

                             COMPLIANCE CERTIFICATE

                          NORTHSTAR ENERGY CORPORATION


         Reference is made to that certain Third Amendment to Canadian Credit
Agreement dated as of July 31, 2001 (the "Third Amendment") among Northstar
Energy Corporation, ("Northstar"), Bank of America Canada, individually and as
administrative agent ("Canadian Agent"), and certain financial institutions
("Lenders"). Terms which are defined in the Third Amendment and which are used
but not defined herein shall have the meanings given them in the Third
Amendment. The undersigned, Paul F. Brereton, does hereby certify that he has
made a thorough inquiry into all matters certified herein and, based upon such
inquiry, experience, and the advice of counsel, does hereby further certify
that:

         1.       He is the duly elected, qualified, and acting Vice
                  President-Finance of Northstar.

         2.       All representations and warranties made by any Restricted
                  Person in any Canadian Loan Document delivered on or before
                  the date hereof are true on and as of the date hereof (except
                  to the extent that the facts upon which such representations
                  are based have been changed by the transactions contemplated
                  in the Third Amendment) as if such representations and
                  warranties had been made as of the date hereof.

         3.       No Default exists on the date hereof.

         4.       Each Restricted Person has performed and complied with all
                  agreements and conditions required in the Canadian Loan
                  Documents to be performed or complied with by it on or prior
                  to the date hereof.

         IN WITNESS WHEREOF, this instrument is executed by the undersigned as
of July 31, 2001.



                                        NORTHSTAR ENERGY CORPORATION



                                        By: /s/ Paul Brereton
                                            ------------------------------------
                                                Paul F. Brereton
                                                Vice President-Finance