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                                                                     Exhibit 3.1
                                                                     -----------

                     RESTATED CERTIFICATE OF INCORPORATION

                                      OF

                       CLARK OIL & REFINING CORPORATION


     The name of the corporation is CLARK OIL & REFINING CORPORATION (the
"Corporation").  The name under which the Corporation was originally
incorporated was AOC Acquisition Corporation.  The date of filing its original
Certificate of Incorporation with the Secretary of State of Delaware was
February 8, 1988.  The dates of filing certain Certificates of Amendment to the
Certificate of Incorporation with the Secretary of State of Delaware were
November 22, 1988, September 13, 1990 and February 1, 1993.

     This Amended and Restated Certificate of Incorporation was duly adopted in
accordance with the provisions of Section 245 of the General Corporation Law of
Delaware.

     1.  The name of the Corporation is CLARK OIL & REFINING CORPORATION (the
"Corporation").

     2.  The address of its registered office in the State of Delaware is
Corporation Trust Center, 1209 Orange Street, County of New Castle, Wilmington,
Delaware 19801. The name of its registered agent at such address is The
Corporation Trust Company.

     3.  The nature or purpose of the business to be conducted or promoted is to
engage in any lawful act or activity for which corporations may be organized
under the General Corporation Law of Delaware.

     4.  The total number of shares of stock which the Corporation shall have
authority to issue is one thousand (1,000) with a par value of each such share
of $0.01, amounting to $10.00 in the aggregate.

     5.  The Corporation is to have perpetual existence.

     6.  In furtherance and not in limitation of the powers conferred by
statute, the board of directors is expressly authorized to make, alter or repeal
the By-laws of the Corporation.

     7.  Meetings of stockholders may be held within or without the State of
Delaware, as the By-laws may provide.  The books of the Corporation may be kept
(subject to any provision contained in the statutes) outside the State of
Delaware at such place or places as may be designated from time to time by the
board of directors or in the By-laws of the Corporation.  Elections of directors
need not be by written ballot unless the By-laws of the Corporation shall so
provide.
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     8.  Directors of the Corporation shall have no personal liability to the
Corporation or its stockholders for monetary damages for breach of fiduciary
duty as a director, except (i) for any breach of a director's duty of loyalty to
the Corporation or its stockholders, (ii) for acts or omissions not in good
faith or which involve intentional misconduct or a knowing violation of law,
(iii) under Section 174 of the General Corporation Law of Delaware, or (iv) for
any transaction from which a director derived an improper personal benefit.

     9.  The Corporation reserves the right to amend, alter, change or repeal
any provision contained in this Certificate of Incorporation, in the manner now
or hereafter prescribed by statute, and all rights conferred upon stockholders
herein are granted subject to this reservation.

     10.  Holders of stock shall not have pre-emptive rights to subscribe for
any new or increased shares of stock of the Corporation.

     IN WITNESS WHEREOF, said CLARK OIL & REFINING CORPORATION has caused this
Amended and Restated Certificate of Incorporation to be signed by Paul D.
Melnuk, its President, and attested by Patrick F. Heider, its Secretary, this
1st day of February, 1993.


                                  CLARK OIL & REFINING CORPORATION



                                  By: /s/ Paul D. Melnuk
                                  --------------------------------------------
                                  Name:  Paul D. Melnuk
                                  Title: President and Chief Executive Officer


ATTEST:


/s/ Patrick F. Heider
---------------------
Name:   Patrick F. Heider
Title:  Secretary

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