August 21, 1997 Mr. Ken Smith Petroglyph Operating Company, Inc. P.O. Box 1839 Hutchinson, KS 67504-1839 Re: Hutch Realty, L.L.C. Lease on Office Building Dear Ken: Pursuant to our recent conversation, we have agreed that the lease dated April 7, 1994...

                                                                   EXHIBIT 10.19

       [Letterhead of Xxxxxx, Xxxxx, Xxxxx, Xxxxx & Xxxxxxx, Chartered]



                                August 21, 1997



Mr. Xxx Xxxxx Petroglyph Operating Company, Inc.
P.O. Box 1839
Hutchinson, KS 67504-1839

     Re:  Hutch Realty, L.L.C. Lease on Office Building

Dear Xxx:

     Pursuant to our recent conversation, we have agreed that the lease dated
April 7, 1994 between Hutch Realty, L.L.C. and Petroglyph Operating Company,
Inc.  Has been extended beyond its two-year primary term and one-year extension
term for an additional one-year period beginning May 7, 1997 through May 6,
1998.  The parties have agreed that the rent will remain the same at $2000 per
month.

     If you have any questions, please feel free to give me a call.

                         Sincerely,
                         HUTCH REALTY, L.L.C.
                         By The Xxx Company, Managing Member



                         By:     /s/ X.X. Xxxxxxxx
                            ----------------------------------------------------
                              X.X. Xxxxxxxx, Agent and Attorney

AJS:se
xc:  Xxxx Xxxxxxxx