FORM OF PROXY FOR SOUTHERN MINERAL CORPORATION EXHIBIT 99.4 SOUTHERN MINERAL CORPORATION PROXY SOLICITED ON BEHALF OF THE BOARD OF DIRECTORS OF SOUTHERN MINERAL CORPORATION FOR A SPECIAL MEETING OF STOCKHOLDERS TO BE HELD ON , 2001 The undersigned shareholder of Southern Mineral Corporation, a Nevada corporation ("Southern Mineral"), hereby appoints Frederic Dormant and Tamara Wagman, and either of them, the lawful attorneys and proxies of the undersigned, with several powers of substitution, to vote all shares of common stock, par value $0.01 per share, of Southern Mineral which the undersigned is entitled to vote at the Special Meeting of Shareholders to be held on , 2001, and any adjournments thereof: 1. To consider and vote upon a proposal to approve the merger agreement among PetroCorp Incorporated, Southern Mineral and PetroCorp Acquisition Company, which is a newly-formed, wholly-owned subsidiary of PetroCorp, and the transactions contemplated by the merger agreement, including the merger. [ ] FOR [ ] AGAINST [ ] ABSTAIN 2. In the discretion of the proxy holders, to transact such other business as may properly come before the meeting or any adjournment or postponement thereof. (Continued and to be dated and signed on the other side) THIS PROXY WILL BE VOTED AS DIRECTED HEREIN BY THE UNDERSIGNED. IN THE ABSENCE OF SPECIFIC INSTRUCTIONS, PROXIES WILL BE VOTED FOR APPROVAL AND ADOPTION OF THE MERGER AGREEMENT AND IN THE DISCRETION OF THE PROXY HOLDERS AS TO ANY OTHER MATTERS THAT MAY PROPERLY COME BEFORE THE MEETING OR ANY ADJOURNMENT OR POSTPONEMENT THEREOF. IF THIS PROXY IS VOTED "AGAINST" THE PROPOSAL TO APPROVE AND ADOPT THE MERGER AGREEMENT, SUCH DISCRETIONARY AUTHORITY WILL NOT BE USED TO VOTE THIS PROXY FOR THE ADJOURNMENT OR POSTPONEMENT OF THE MEETING TO PERMIT FURTHER SOLICITATION OF PROXIES. THE BOARD OF DIRECTORS IS NOT AWARE OF ANY MATTER WHICH IS TO BE PRESENTED FOR ACTION AT THE MEETING OTHER THAN THE MATTERS SET FORTH HEREIN. THE BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS THAT THE SHAREHOLDERS OF AMFM VOTE FOR THE APPROVAL AND ADOPTION OF THE MERGER AGREEMENT. Signature: -------------------------------- -------------------------------- Date: , 2001 - -------------------------------------------------------------------------------- NOTE: Please sign exactly as name appears hereon. Joint owners should each sign. When signing in a fiduciary or representative capacity, please give full title as such.