EXHIBIT 5.1 Opinion Regarding Legality by Snell & Wilmer, L.L.P. [Letterhead of Snell & Wilmer, L.L.P.] October 29, 1999 Securities and Exchange Commission Judiciary Plaza 450 Fifth Street, N.W. Washington, D.C. 20549 Re: Mason Oil Company, Inc. Form S-8 Registration Statement Executive Stock Plan Ladies and Gentlemen: This firm has acted as counsel to Mason Oil Company, Inc. (the "Company") in connection with the preparation and filing of its registration statement on Form S-8 under the Securities Act of 1933, as amended, covering the issuance of an aggregate of 4,600,000 shares of common stock, $0.001 par value per share of the Company (the "Common Stock"), pursuant to the Executive Stock Plan (the "Plan"). We have examined the Company's Articles of Incorporation and bylaws and the record of its corporate proceedings with respect to the registration statement and have made such other investigation as we have deemed necessary in order to express the following opinion. Based on the foregoing, we are of the opinion that: 1. The Company has been duly incorporated and is validly existing and in good standing as a corporation under the laws of the State of Utah. 2. The Common Stock, when issued as contemplated by the Plan and the registration statement will be legally issued, fully paid and nonassessable. We hereby consent to all references to this firm in the registration statement and all amendments to the registration statement. We further consent to the use of this opinion as an exhibit to the registration statement. Very truly yours, /s/Snell & Wilmer, L.L.P. Snell & Wilmer, L.L.P.