1 NOTICE OF GUARANTEED DELIVERY FOR SHARES OF SERIES A 8% CUMULATIVE CONVERTIBLE PREFERRED STOCK OF MESA INC. SUBSCRIBED FOR UNDER THE BASIC SUBSCRIPTION AND THE OVERSUBSCRIPTION PRIVILEGE As set forth in the Prospectus under "The Rights Offering -- Exercise of Rights," this form or one substantially equivalent hereto may be used as a means of effecting subscription and payment for all shares of Mesa's Series A 8% Cumulative Convertible Preferred Stock. Such form may be delivered by hand or sent by telex, facsimile transmission, overnight courier or mail to the Subscription Agent. The Subscription Agent is: AMERICAN STOCK TRANSFER AND TRUST COMPANY Attention: Corporate Stock Transfer Department By Mail By Facsimile By Hand 40 Wall Street, 46th Floor (718) 234-5001 40 Wall Street, 46th Floor New York, NY 10005 New York, NY 10005 Confirm by telephone to: (718) 921-8200 By Overnight Courier: Corporate Stock Transfer Department 40 Wall Street, 46th Floor New York, NY 10005 DELIVERY OF THIS INSTRUMENT TO AN ADDRESS, OR TRANSMISSION OF INSTRUCTIONS VIA A TELECOPY FACSIMILE NUMBER, OTHER THAN AS SET FORTH ABOVE, DOES NOT CONSTITUTE A VALID DELIVERY Prior to 5:00 p.m., New York City time, on the Expiration Date, the member firm of a registered national securities exchange or member of the National Association of Securities Dealers, Inc., or commercial bank or trust company which completes this form must communicate the guarantee, the name of the exercising Rights holder, the number of Rights represented by the Subscription Certificate(s) held by such exercising holder and the number of shares subscribed for (under both the Basic Subscription Privilege and the Oversubscription Privilege) to the Subscription Agent and must deliver this Notice of Guaranteed Delivery, together with payment in full for all subscribed shares, guaranteeing delivery of a properly completed and signed copy of the Subscription Certificate to the Subscription Agent. Failure to do so will result in a forfeiture of the Rights. GUARANTEE The undersigned, a member firm of a registered national securities exchange or member of the National Association of Securities Dealers, Inc., or a commercial bank or trust company having an office or correspondent in the United States, guarantees delivery to the Subscription Agent by the close of business on the third New York Stock Exchange trading day following the date hereof, of a properly completed and duly executed Subscription Certificate and evidencing the Rights being exercised as indicated herein. Number of Rights to be delivered ------------------------ Method of delivery (circle one) A. Through DTC* B. Direct to Subscription Agent 2 - ------------------------------------------------------ ------------------------------------------------------ Number of Shares Subscribed for Pursuant to Number of Shares Subscribed for Pursuant to Basic Subscription Privilege Oversubscription Privilege - ------------------------------------------------------ ------------------------------------------------------ Name of Firm Authorized Signature - ------------------------------------------------------ ------------------------------------------------------ Address Title Name - ------------------------------------------------------ ---------------------------------------------- Zip Code (Please Type or Print) - ------------------------------------------------------ ------------------------------------------------------ Contact Name Phone Number - --------------- * IF THE RIGHTS ARE DELIVERED THROUGH DTC, A REPRESENTATIVE OF AMERICAN STOCK TRANSFER AND TRUST COMPANY WILL PHONE YOU WITH A PROTECT IDENTIFICATION NUMBER, WHICH NEEDS TO BE RELATED BY YOU TO DTC.