Exhibit 8.1

                      [Mayer, Brown, Rowe & Maw Letterhead]

                                 March 7, 2003

Devon Energy Corporation
20 North Broadway, Suite 1500
Oklahoma City, Oklahoma 73102

Ladies and Gentlemen:

         In connection with the registration statement on Form S-4 (the
"Registration Statement") filed by Devon Energy Corporation, a Delaware
corporation ("Devon"), relating to the merger (the "Merger") contemplated by the
Agreement and Plan of Merger, dated as of February 23, 2003 (the "Merger
Agreement"), by and among Devon, Devon NewCo Corporation and Ocean Energy, Inc.,
you have requested our opinion regarding the description of material tax
consequences related to the Merger as described in the Registration Statement.

         In formulating our opinion, we have examined the Merger Agreement and
the Registration Statement, including the joint proxy statement/prospectus that
forms a part of the Registration Statement. In addition, we have examined such
other documents, instruments and information as we considered necessary to
enable us to express this opinion. Our opinion is also based on (1) the accuracy
of the statements and facts concerning the Merger set forth in the Merger
Agreement (including, without limitation, the exhibits thereto) and the
Registration Statement, (2) the consummation of the Merger in the manner
contemplated by, and in accordance with the terms set forth in, the Merger
Agreement and the Registration Statement and (3) currently applicable provisions
of the U.S. federal income tax laws, including the Internal Revenue Code of
1986, as amended, applicable Treasury Regulations promulgated thereunder,
judicial authority and current administrative rulings and practice.

         Based on the foregoing, as of the date hereof, we adopt and confirm the
statements under the caption "Material Federal Income Tax Considerations" in the
Registration Statement as our opinion of the material tax consequences of the
Merger, to the extent that such statements constitute legal conclusions. We know
that we are referred to in the Registration Statement, and we hereby consent to
the use of our name therein and to the filing of this opinion as part of the
Registration Statement, without admitting that we are "experts" within the
meaning of the Securities and Exchange Act of 1933, as amended, or the rules and
regulations of the Securities and Exchange Commission issued thereunder, with
respect to any part of the Registration Statement.

                                                 Sincerely,

                                                 /s/ MAYER, BROWN, ROWE & MAW
                                                 ----------------------------
                                                 Mayer, Brown, Rowe & Maw