UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                                    FORM 8-K

                                 CURRENT REPORT

     PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

                Date of Report(Date of earliest event reported):
                      December 29, 1999(November 18, 1999)


                       ST. MARY LAND & EXPLORATION COMPANY
             (Exact name of Registrant as specified in its charter)


          Delaware                 0-20872               41-0518430
      (State or other          (Commission File       (I.R.S Employer
      Jurisdiction of              Number)           Identification No.)
      incorporation or
        organization)



             1776 Lincoln Street, Suite 1100, Denver, Colorado 80203
               (Address of principal executive offices) (Zip Code)


        Registrant's telephone number, including area code:(303)861-8140


                                 Not applicable
         (Former name or former address, if changed since last report)




ITEM 2.        Acquisition or Disposition of Assets.

     On December 17, 1999,  St. Mary Land &  Exploration  Company  completed the
acquisition of King Ranch Energy,  Inc. under a merger  agreement dated July 27,
1999.  In the merger St Mary  issued  2,666,252  shares of its  common  stock to
shareholders  of King Ranch,  Inc., the former parent of King Ranch Energy.  The
merger agreement provides that the shares of St. Mary common stock issued in the
acquisition  cannot be  transferred  until  March 31,  2001.  As a result of the
merger King Ranch Energy  became a wholly owned  subsidiary  of St. Mary and was
renamed St. Mary Energy  Company.  In addition,  Jack Hunt and William  Gardner,
officers of King Ranch,  Inc., were appointed to the St. Mary board of directors
under the terms of the merger agreement.

     King Ranch Energy is an oil and gas exploration and production company with
oil and gas properties  located  primarily in the Gulf of Mexico and the onshore
Gulf Coast.  1998  production was 48.8 million cubic feet (MMCF)  equivalent per
day.  Reported oil and gas reserves at December  31, 1998,  plus an  acquisition
made in early  1999,  were 64.7  billion  cubic  feet (BCF)  equivalent  and 82%
natural gas.

     The press  release of St.  Mary dated  December  17,  1999  announcing  the
completion  of the  acquisition  is  attached  as an  exhibit  to  this  report.
Additional  information  concerning the acquisition is included in the financial
statements  of King Ranch Energy and the pro forma  financial  statements of St.
Mary referred to under Item 7 below.

     St. Mary cautions that this report and the attached  press release  contain
forward-looking  statements  that  include  statements  concerning  the benefits
expected to result from the  acquisition,  including  expected  exploration  and
production  enhancements.  Significant factors that could cause future events or
results  to  differ   materially   from  those   expressed  or  implied  by  the
forward-looking  statements include St. Mary's ability to successfully integrate
the businesses of St. Mary and King Ranch Energy.

ITEM 5.        Other Events.

On November  18,  1999,  Robert L. Nance was  appointed  to St.  Mary's board of
directors to replace Richard C. Kraus, who resigned.

ITEM 7.        Financial Statements and Exhibits

     (a)  Financial statements of businesses acquired.

          The audited  financial  statements of King Ranch Energy for  the years
     ended December 31, 1998, 1997 and 1996 are included in St. Mary's Amendment
     No. 2 to Registration  Statement on  form S-4  (Registration No. 333-85537)
     filed  with  the SEC on  November 12, 1999  and  are incorporated herin  by
     reference.

                                       2



          Pursuant to SEC rules,  the  unaudited  financial  statements  of King
     Ranch Energy for the nine months ended  September 30, 1999 and 1998 will be
     filed by an amendment to this report not later than March 1, 2000.

     (b)  Pro forma financial information.

          Pursuant to SEC rules, the pro forma financial  statements of St. Mary
     for the nine  months  ended  September  30,  1999 which give  effect to the
     acquisition  of King Ranch  energy  will be filed by an  amendment  to this
     report not later than March 1, 2000.

     (c)  Exhibits.

     The following exhibits are furnished as part of this report:

     Exhibit 2.1    Agreement and Plan of Merger dated July 27, 1999  among  St.
                    Mary Land &  Exploration  Company, St. Mary  Energy Company,
                    King Ranch, Inc., and King  Ranch Energy,  Inc., as  amended
                    by  Amendment  Nos. 1 and 2 dated November 8, 1999 (filed as
                    Exhibit 2.1 to St.  Mary's  Amendment  No. 2 to Registration
                    Statement on Form S-4 (Registration No. 333-85537)filed with
                    the SEC on  November 12, 1999  and  incorporated  herein  by
                    reference)

     Exhibit 23.1   Consent of Deloitte & Touche LLP*

     Exhibit 99.1   Press  release  of St. Mary Land & Exploration Company dated
                    December 17, 1999*

- ---------------------------
*Filed herewith

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                                   SIGNATURES
                                   ----------


     Pursuant to the  requirements  of the  Securities and Exchange Act of 1934,
the  Registrant  has duly  caused  this report to be signed on its behalf by the
undersigned  hereunto duly authorized.

                                             ST. MARY LAND & EXPLORATION COMPANY

Date:December 22, 1999                           By /s/ MARK A. HELLERSTEIN
                                                 --------------------------
                                                 Mark A. Hellerstein
                                                 President  and  Chief Executive
                                                 Officer


Date:December 22, 1999                           By  /s/ RICHARD C. NORRIS
                                                 -------------------------
                                                 Richard C. Norris
                                                 Vice  President   -    Finance,
                                                 Treasurer and Secretary