EXHIBIT 10.40

                           [COMPASS BANK LETTERHEAD]

September 30, 1999

Mr. Steven H. Mikel
President & CEO
Southern Mineral Corporation
1201 Louisiana Street, Suite 3350
Houston, Texas 77002-5609

     RE:  Amended and Restated Credit Agreement dated June 19, 1998, by and
          between Southern Mineral Corporation, SMC Ecuador, Inc., SMC
          Production Co., BEC Energy, Inc., Amerac Energy Corporation, Compass
          Bank and First Union National Bank (as subsequently amended, restated,
          and/or supplemented, the "Credit Agreement")

Dear Steve:

Section 2.5 (a) of the Credit Agreement shall be amended to change the date of
September 30, 1999 to October 8, 1999.

Except as expressly provided herein, the Credit Agreement and the other Loan
Documents shall remain in full force and effect in accordance with their
respective terms and this letter shall not be construed to:

      (i)   impair the validity, perfection or priority of any lien or security
            interest securing the Obligations;
      (ii)  waive or impair any rights, powers or remedies of the Agent and the
            Lenders under the Credit Agreement and the other Loan Documents; or
      (iii) grant any forbearance periods or extend the term of the Credit
            Agreement or the time for payment of any of the Obligations, except
            as expressly provided herein.

No Event of Default and no Default is waived or remedied by the execution of
this letter by the Lenders, and any such Default or Event of Default heretofore
arising and currently continuing shall continue after the execution and delivery
hereof.  Nothing contained in this letter, nor any past indulgence by the
Lenders, nor any prior waiver or consents or any waivers or consents which may
hereafter be granted nor any other action or inaction on behalf of the Lenders
(i) shall constitute or be deemed to constitute a waiver of any Defaults or
Events of Default which exist or may exist under the Credit Agreement or any
other Loan Document, or (ii) shall constitute or be deemed to constitute an
election of remedies by the Lenders or a waiver of any of the rights or remedies
of the Lenders provided in the Credit Agreement or the other Loan Documents or
otherwise afforded at law or in equity.


Mr. Steven H. Mikel
September 30, 1999
Page 2


THIS LETTER, THE AGREEMENT AND THE OTHER WRITTEN LOAN DOCUMENTS
REPRESENT, COLLECTIVELY, 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 BETWEEN THE
PARTIES.

Sincerely,

COMPASS BANK


By:/s/ Dorothy Marchand Wilson
   ---------------------------
       Dorothy Marchand Wilson
       Senior Vice President


FIRST UNION NATIONAL BANK

By:  __________________________

Its:  __________________________



ACKNOWLEDGED AND AGREED:

SOUTHERN MINERAL CORPORATION

/s/ Michael. E. Luttrell
- ------------------------
Michael E. Luttrell
Vice President & CFO