EXHIBIT 4.42

                               SIXTH AMENDMENT TO
                              AMENDED AND RESTATED
                       CERTIFICATE OF LIMITED PARTNERSHIP
                                       OF
                GEODYNE ENERGY INCOME LIMITED PARTNERSHIP I-F

      The undersigned, desiring to amend its Amended and Restated Certificate of
Limited Partnership pursuant to the Oklahoma Revised Uniform Limited Partnership
Act, as amended,  54 O.S. ss.301 et seq.  (Supp.1999)  (the "Act"),  does hereby
state:

      1. The name of the limited  partnership  is Geodyne  Energy Income Limited
Partnership I-F (the "Partnership").

      2. The dates of filing  the  Certificate  of Limited  Partnership  and all
amendments thereto are as follows:

Name                                                              Date
Agreement and Certificate of Limited Partnership                  3/11/86
Amended and Restated Agreement and Certificate of
      Limited Partnership                                         9/11/86
First Amendment to Amended and Restated Agreement
      and Certificate of Limited Partnership                      2/9/87
Second Amendment to Amended and Restated Agreement
      and Certificate of Limited Partnership                      5/20/87
Third Amendment to Amended and Restated Agreement
      and Certificate of Limited Partnership                      8/24/87
Fourth Amendment to Amended and Restated Agreement
      and Certificate of Limited Partnership                      11/24/87
Amended and Restated Certificate of Limited
      Partnership                                                 3/10/89
First Amendment to Amended and Restated Certificate
      of Limited Partnership                                      2/25/93
Second Amendment to Amended and Restated Certificate
      of Limited Partnership                                      7/19/96
Third Amendment to Amended and Restated Certificate
      of Limited Partnership                                      12/29/99
Fourth Amendment to Amended and Restated Certificate
      of Limited Partnership                                      11/14/01
Fifth Amendment to Amended and Restated Certificate
      of Limited Partnership                                      11/21/03

3.  The  Fifth  Amendment  to  Amended  and  Restated   Certificate  of  Limited
Partnership  dated November 21, 2003,  and filed with the Oklahoma  Secretary of
State on November 24,  2003,  stated that the latest date upon which the limited
partnership  is to dissolve is December  31,  2005.  Pursuant to its terms,  the
Amended and Restated  Certificate  and  Agreement of Limited  Partnership  dated
December 17, 1986 (the "Partnership Agreement") was amended on October 27, 2005,
to state  that the latest  date upon which the  Partnership  is to  dissolve  is
December 31, 2007,  provided that the General Partner may extend the term of the
Partnership  for up to  one  additional  period  of two  years  pursuant  to the
provisions of the Partnership Agreement.

      Therefore,  the Amended and Restated Certificate of Limited Partnership is
hereby  revised  to state that the latest  date on which the  Partnership  is to
dissolve  is  December  31,  2007,  subject  to  extension  as set  forth in the
Partnership's Partnership Agreement.

      DATED: October 27, 2005.
                                    GEODYNE RESOURCES, INC.
                                    General Partner


                                    By://s// Dennis R. Neill
                                       -----------------------------
                                       Dennis R. Neill, President