EXHIBIT 10.1

                                SECOND AMENDMENT

                                       TO

                           AGREEMENT FOR GROUND LEASE

                                    between

                           BRAZOS RIVER LEASING L.P.

                                      and

                 DIAMOND SHAMROCK REFINING AND MARKETING COMPANY

                           Dated as of April 23, 1994



This Second Amendment to Agreement for Ground Lease has been manually     
executed in 8 counterparts, numbered consecutively from 1 through 8, of     
which this is No. _____.  To the extent, if any, that this Second Amendment   
to Agreement for Ground Lease constitutes chattel paper (as such term is     
defined in the Uniform Commercial Code as in effect in any jurisdiction),     
no security interest in this Second Amendment to Agreement for Ground Lease   
may be created or perfected through the transfer or possession of any     
counterpart other than the original counterpart which shall be the     
counterpart identified as counterpart No. 1.

     

                     SECOND AMENDMENT TO AGREEMENT FOR GROUND LEASE


     This Second Amendment to Agreement for Ground Lease is made and     
entered into as of April 23, 1994, by and between BRAZOS RIVER LEASING L.P.  
("Brazos") and DIAMOND SHAMROCK REFINING AND MARKETING COMPANY ("Diamond     
Shamrock R & M").

                              W I T N E S S E T H:

     WHEREAS, Brazos and Diamond Shamrock R & M have heretofore entered     
into an agreement for Ground Lease, dated as of April 23, 1992 (as amended    
by the First Amendment to Agreement for Ground Lease dated as of August 1,    
1992, referred to herein together as the "Agreement for Ground Lease"); and

     WHEREAS, Brazos and Diamond Shamrock R & M desire to amend the Agreement
for Ground Lease to extend the acquisition period and to otherwise set forth
their mutual agreement; and

     WHEREAS, Brazos and Diamond Shamrock R & M agree that the provisions of
this amendment shall apply, to the extent provided by law, to each Property
hereafter acquired by Brazos under the Agreement for Ground Lease.

     NOW, THEREFORE, in consideration of the mutual covenants herein
contained and other valuable consideration, the receipt and sufficiency of    
which are hereby acknowledged, Brazos and Diamond Shamrock R & M agree that 
the Agreement for Ground Lease is hereby amended as follows:

     1.   Section 3.06 of the Agreement for Ground Lease is hereby amended    
 by deleting in subsection (i) in Section 3.06, the reference to "two years"
and inserting in lieu thereof "four years".

     2.   Brazos and Diamond Shamrock R & M agree that this Second Amendment
to Agreement for Ground Lease shall not be effective until the approvals
required by Section 9.01 of the Credit Agreement have been obtained as
evidenced by the execution of Amendment No. 2 by the necessary parties under
the Credit Agreement.

     3.   Defined terms used in this second Amendment to Agreement for Ground
Lease and not otherwise defined herein have the meanings ascribed to those
terms in the Agreement for Ground Lease.

     IN WITNESS WHEREOF, Brazos and Diamond Shamrock R & M have caused this
Second Amendment to Agreement for Ground Lease to be executed and delivered  
by their duly authorized officers as of the day and year first above written.

                                        BRAZOS RIVER LEASING L.P.

                                        By:  Headwater Investments L.P.,
                                             its General Partner

                                             By:  Headwater Holdings, Inc.,
                                                  its General Partner


                                             By:___________________________   
                                                  Gregory C. Greene,
                                                  President



                                        DIAMOND SHAMROCK REFINING AND
                                             MARKETING COMPANY



                                        By: /S/ R.C. BECKER
                                        Name:   R.C. Becker
                                        Title:  Vice President and
                                                  Treasurer