SIXTH AMENDMENT TO FIRST AMENDED AND RESTATED CREDIT AGREEMENT

     THIS SIXTH AMENDMENT TO FIRST AMENDED AND RESTATED  CREDIT  AGREEMENT (this
"Amendment") is made as of the 1st day of July,  1997, by and among CAIRN ENERGY
USA, INC., a Delaware corporation ("Borrower"),  ING (U.S.) CAPITAL CORPORATION,
f/k/a Internationale Nederlanden (U.S.) Capital Corporation, as agent ("Agent"),
and  ING  (U.S.)  capital   corporation   ("ING   Capital"),   MEESPIERSON  N.V.
("MeesPierson"),  and CREDIT  LYONNAIS NEW YORK BRANCH ("Credit  Lyonnais"),  as
lenders (collectively, "Lenders").

                                   RECITALS:
                                   --------

     Borrower,  Agent and Lenders  entered into that certain  First  Amended and
Restated  Credit  Agreement dated as of December 20, 1994, as amended by a First
Amendment to First  Amended and Restated  Credit  Agreement  dated  December 12,
1995, a Second  Amendment to First Amended and Restated  Credit  Agreement dated
January  15,  1996,  a Third  Amendment  to First  Amended and  Restated  Credit
Agreement dated June 28, 1996, a Fourth  Amendment to First Amended and Restated
Credit  Agreement  dated November 7, 1996 and a Fifth Amendment to First Amended
and Restated Credit  Agreement dated March 14, 1997 (the "Original  Agreement"),
for the purposes and consideration therein expressed,  pursuant to which Lenders
made and became  obligated  to make loans to Borrower as therein  provided;  and
Borrower, Agent and Lenders  desire to amend the Original  Agreement as provided
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 Lenders to 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,  and the following terms when used in this Amendment shall have
the following meangins: Original Agreement shall have the same meanings:

          "Amendment"  means this Sixth  Amendment to First Amended and Restated
     Credit Agreement.

          "Amendment/Allonge"  has  the  meaning  given  it in  Section  3.1(ii)
     hereof.

          "Amendment Documents" means this Amendment and each Amendment/Allonge.

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

                 ARTICLE II - Amendments to Original Agreement

     Section  2.1.  Defined  Terms.  The  definition  of  "Facility A Commitment
Period" set forth in Section 1.1 of the Original  Agreement is hereby amended in
its entirety to read as follows:

          "Facility A Commitment Period" means the period from and including the
     date hereof until and inculding January 1, 1998 (or, if earlier, the day on
     which the Facility A Notes first become due and payable in full).

          Section  2.2.  Amendment  to  Regular  Payments.  Section  2.8  of the
     Original Agreement is hereby amended in its entirety to read as follows:

               Section 2.8 Regular  Payments.  Borrower will pay interest on the
          Loans as specified  in the Notes.  Borrower  will repay the  aggregate
          principal  amount of the Facility A Loans  outstanding on the last day
          of the  Facility  A  Commitment  period  in  thirteen  (13)  quarterly
          installments,  on the  first  day of each  April,  July,  October  and
          January,  beginning April 1, 1998. The first such installment shall be
          in an amount equal to twenty  percent  (20%) of the  aggregate  unpaid
          principal balance of the Facility A Loans at the end of the Facility A
          Commitment Period; each of the next two (2) such installments shall be
          in an  mount  equal  to ten  percent  (10%)  of the  aggregate  unpaid
          principal balance of the Facility A Loans at the end of the Facility A
          Commitment  Period;  each of the next four (4) such installments shall
          be in an amount  equal to nine percent  (9%) of the  aggregate  unpaid
          principal balance of the Facility A Loans at the end of the Facility A
          Commitment  Period;  and each of the  last  six (6) such  installments
          shall be in an  amount  equal to four  percent  (4%) of the  aggregate
          unpaid  principal  balance  of the  Facility A Loans at the end of the
          Facility A Commitment Period. Such amounts shall be rounded upwards to
          the  nearest  $1,000.  Agent shall  determine  the amount of each such
          principal  installment,  which  amount  shall  be  conclusive,  absent
          manifest error.  Borrower will repay the aggregate principal amount of
          the Facility B Loans on the maturity  date set forth in the Facility B
          Notes.

                    ARTICLE III - Conditions of Effectiveness

     Section 3.1.  Effective Date.  This Amendment shall become  effective as of
the date first above written when (i) Agent shall have  received this  Amendment
at Agent's office duly  authorized,  executed and delivered by Borrower and each
Lender,  (ii)  Borrower  shall  have  issued  and  delivered  to each  Lender an
Amendment and Allonge (each an  "Amendment/Allonge")  to each Facility A Note in
the form  attached  hereto as Attachment 1, duly executed on behalf of Borrower,
and (iii) Agent shall have additionally  received all of the following documents
each being duly  authorized,  executed and delivered,  and in form and substance
satisfactory to Agent and each Lender:

          (a) Omnibus  Certificate.  An Omnibus Certificate of the Secretary and
     of the  Chairman  of the Board,  President  or a Senior Vice  President  of
     Borrower of even date with this  Amendment,  which shall  contain the names
     and  signatures of the officers  authorized  to execute this  Amendment and
     which shall certify to the truth,  correctness  and  completeness as of the
     date hereof of: (i) all of the exhibits  attached to that  certain  Omnibus
     Certificate dated as of November 7, 1996 made by such officers of Borrower,
     and (ii) a copy of  resolutions  duly  adopted by the Board of Directors of
     Borrower and in full force and effect at the time this Amendment is entered
     into, authorizing the execution of this Amendment.

          (b)  Compliance  Certificate.  A Compliance  Certificate of the Senior
     Vice  President-Finance of Borrower,  of even date with this Amendment,  in
     which such officer shall  certify,  to the best of his knowledge and belief
     after  due  inquiry,  to the  satisfaction  of the  conditions  set  out in
     subsections  (a) through  (d),  inclusive  of Section  3.2 of the  Original
     Agreement as of the date hereof.

             ARTICLE IV - Representations, Warranties and Covenants

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

          (a) The representations and warranties contained in Section 4.1 of the
     Original  Agreement  are  true  and  correct  at and as of the  time of the
     effectiveness  hereof,  except to the extent that such  representations and
     warranties  are  made in the  Original  Agreement  only in  reference  to a
     specific  date and  except to the  extent  that the facts  upon  which such
     representations  are based  have been  changed by the  extension  of credit
     under the Credit Agreement.

          (b) Borrower is duly  authorized to execute and deliver this Amendment
     and each  other  Amendment  Document  and is and will  ctoninue  to be duly
     authorized  to  borrower  and to  perform  its  obligations  hereunder  and
     thereunder.


          (c) The execution and delivery by borrower of this  Amendment and each
     other  Amendment  Document  and the  performance  by it of its  obligations
     hereunder  and under  the  Credit  Agreement  and the  consummation  of the
     transactions  contemplated  hereby and thereby do not and will not conflict
     with any provision of law,  statute,  rule or regulation or of the articles
     of  incorporation  or  bylaws of  Borrower  or of any  material  agreement,
     judgment,  license,  order or permit applicable to or binding upon Borrower
     or  result in the  creation  of any lien,  charge or  encumbrance  upon any
     assets or properties of Borrower,  except as expressly  contemplated in the
     Loan Documents. Except for those which have been duly obtained, no consent,
     approval,  authorization or order of any court or governmental authority or
     third party is required in  connection  with the  execution and delivery by
     Borrower of this  Amendment or any Amendment  Document or to consummate the
     transactions contemplated hereby and thereby.

          (d) When this  Amendment  and each other  Amendment  Document  is duly
     executed  and  delivered,  each  of this  Amendment,  the  other  Amendment
     Documents and the Credit  Agreement will be a legal and binding  instrument
     and agreement of Borrower, enforceable in accordance with its terms, except
     as  limited  by  bankruptcy,  insolvency  and  similar  laws and be general
     principles of equity.

          (e) The audited annual Consolidated  financial  statements of Borrower
     dated as of  December 31,  1996 and the  unaudited  quarterly  Consolidated
     financial  statements of Borrower dated as of March 31, 1997 fairly present
     the  Consolidated  financial  position  at such dates and the  Consolidated
     statement of operations and cash flows for the periods ending on such dates
     for Borrower.  Copies of such financial  statements  have  heretofore  been
     delivered to Lender.  Since March 31, 1997, no material  adverse change has
     occurred in the  financial  condition  or  business or in the  Consolidated
     financial condition or businesses of Borrower.

                            ARTICLE V - Miscellaneous

          Section 5.1.  Ratification  of Agreements.  The Original  Agreement as
     hereby amended is hereby  ratified and confirmed in all respects.  The Loan
     Documents,  as they may be amended or  affected by this  Amendment  and the
     other  Amendment  Documents,  are  hereby  ratified  and  confirmed  in all
     respects.  Any reference to the Credit Agreement in any Loan Document shall
     be deemed to refer to this  Amendment  also and any  referenced in any Loan
     Document to any other document or instrument amended,  renewed, extended or
     otherwise affected by this Amendment or the other Amendment Documents shall
     also refer to such Amendment and such Amendment  Documents.  The execution,
     delivery  and  effectiveness  of this  Amendment  and each other  Amendment
     Document  shall not  operate as a waiver of any  right,  power or remedy of
     Agent or any Lender under the Credit  Agreement or any other Loan  Document
     nor  constitute a waiver of any  provision  of the Credit  Agreement or any
     other Loan Document.

          Section 5.2. Survival of Agreements. All representations,  warranties,
     covenants and agreements of 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 Borrower
     hereunder  or under the Credit  Agreement  to Agent or any Lender  shall be
     deemed to constitute  representations  and warranties by, or agreements and
     covenants of, Borrower under this Amendment and under the Credit Agreement.

          Section 5.3.  Protection  of Security  Interests  and Liens.  Borrower
     agrees to deliver to Agent within fifteen days after request any additional
     amendments or supplements to any Security Documents, properly completed and
     executed  (and  acknowledged  when  required)  by  Borrower,  in  form  and
     substance  satisfactory to Agent,  which Agent reasonably  requests for the
     purpose of perfecting,  confirming, or protecting any Liens or other rights
     in Collateral securing any Obligations.

          Section 5.4. Loan  Documents.  This Amendment and each other Amendment
     Document is a Loan  Document,  and all  provisions in the Credit  Agreement
     pertaining to Loan Documents apply hereto.

          Section 5.5.  GOVERNING LAW. THIS  AMENDMENT  SHALL BE GOVERNED BY AND
     CONSTRUED  IN  ACCORDANCE  WITH THE  LAWS OF THE  STATE OF NEW YORK AND ANY
     APPLICABLE LAWS OF THE UNITED STATES OF AMERICA IN ALL RESPECTS,  INCLUDING
     CONSTRUCTION, VALIDITY AND PERFORMANCE.

          Section 5.6.  Counterparts.  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.

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

                                            CAIRN ENERGY USA, INC.



                                            By:      /s/ A. Allen Paul
                                            A. Allen Paul, Senior Vice President
                                            Finance