UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    Form 13F

                               Form 13F COVER PAGE

Report for the Calendar Year or Quarter: June 30, 2002
                                         -----------------

Check here if Amendment [_]; Amendment Number: ____
This Amendment (Check only one.):  [_] is a restatement.
                                   [_] adds new holdings entries.

Institutional Investment Manager Filing this Report:

Name: Markel Corporation
Address: 4521 Highwoods Pkwy
         Glen Allen, VA 23060

Form 13F File Number: 28-6647
                      --------------

The institutional investment manager filing this report and the person by whom
it is signed hereby represent that the person signing the report is authorized
to submit it, that all information contained herein is true, correct and
complete, and that it is understood that all required items, statements,
schedules, lists, and tables, are considered integral parts of this form.

Person Signing this Report on Behalf of Reporting Manager:

Name: Thomas S. Gayner
Title: Chief Investment Officer
Phone: 804-527-3806

Signature, Place, and Date of Signing:

Thomas S. Gayner              Richmond, VA                     8/8/02
----------------------     ----------------------------     -------------------
[Signature]                [City, State]                     [Date]

Report Type (Check only one.):

[_]  13F HOLDINGS REPORT. (Check here if all holdings of this reporting manager
     are reported in this report.)

[X]  13F NOTICE.  (Check here if no holdings reported are in this report, and
     all holdings are reported by other reporting manager(s).)

[_]  13F COMBINATION REPORT. (Check here if a portion of the holdings for this
     reporting manager are reported in this report and a portion are reported by
     other reporting manager(s).)

List of Other Managers Reporting for this Manager:

Form 13F File Number                             Name
--------------------                             ----
28-6056                             Markel Gayner Asset Management Corporation