Document:

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                                                                  EXHIBIT 10.7.1
                                                                  --------------

                               December 20, 1999

To the Banks and Financial Institutions
Listed on Schedule 1 Hereto

     Re:  Credit Agreement dated as of June 24, 1999 (as amended to date, the
          "Credit Agreement") among Titan Exploration, Inc. as Borrower
          ("Borrower"), Chase Bank of Texas, National Association, as Agent and
          the Lenders Signatory Thereto

Ladies and Gentlemen:

     Reference is made to the Credit Agreement for the meanings of terms defined
therein which, unless otherwise defined in this letter, shall have the same
meanings when used herein.

     As you know, Unocal Corporation ("Unocal") and Borrower have agreed to
merge Unocal's oil and gas exploration and production assets in the Permian and
San Juan basins with Titan into a new publicly traded company to be named Pure
Energy Resources, Inc. ("Pure"). Pure will form a wholly owned subsidiary, TRH,
Inc. ("TRH"), which will be merged into Borrower, with Borrower to be the
surviving corporation. As part of the merger, Borrower's existing shareholders
will receive approximately thirty-five percent of the common stock of Pure, and
Unocal will retain approximately sixty-five percent of the common stock of Pure.
This transaction (the "Merger") is more fully described in the Agreement and
Plan of Merger dated December 13, 1999 (the "Merger Agreement") among Union Oil
Company of California, Titan Resources Holdings, Inc., TRH, and Borrower, a copy
of which is enclosed with this letter.

     As a result of the Merger, Borrower will be a wholly owned subsidiary of
Pure.  Pure will initially have one or more other subsidiaries (the "Other
Subsidiaries") that will not be owned by Borrower or any of Borrower's
Subsidiaries.  The Permian and San Juan assets to be contributed to Pure by
Unocal will initially be held in the Other Subsidiaries.

     The Merger and the other transactions contemplated in the Merger Agreement
(collectively, the "Transactions") may violate the following provisions of the
Credit Agreement:

          Section 5.03(c) restricting mergers,

          Section 5.03(k), restricting certain transactions with Affiliates, and

          Section 6.13, providing for a Change in Control to constitute an Event
of Default.

As a result of the Transactions, Unocal and its Subsidiaries may also become
ERISA Affiliates of Borrower and its Subsidiaries.

     Borrower hereby requests Lenders' and Agent's consent to the Transactions
and their waiver of the provisions of Sections 5.03(c), 5.03(k), and 6.13 of the
Credit Agreement (and any similar provisions of the Financing Documents) which
would be violated by the Transactions. Borrower further requests Lenders' and
Agent's agreement that (a) the term "ERISA Affiliate" in the Credit Agreement
will hereafter refer only to Borrower and its own Subsidiaries and (b) the term
"Maturity Date" in the Credit Agreement will hereafter refer to April 1, 2001
rather than January 1, 2001.

     Please execute a copy of this letter in the space provided below to
evidence this requested consent, waiver, and agreement:
<PAGE>

     Thank you very much for your cooperation.

Yours truly,

TITAN EXPLORATION, INC.

By: /s/ John L. Benfatti
    -----------------------------------------------
    Name:  John L. Benfatti
           ----------------------------------------
    Title: Vice President - Accounting & Controller
           ----------------------------------------

CONSENTED TO AND AGREED and
WAIVED as of the date first written above:

CHASE BANK OF TEXAS, NATIONAL
 ASSOCIATION
Individually, as Issuing Bank, and as
Administrative Agent

By: /s/ Robert C. Mertensotto
    -----------------------------------------------
    Name:  Robert C. Mertensotto
           ----------------------------------------
    Title: Managing Director
           ----------------------------------------

FIRST UNION NATIONAL BANK, Individually and as Documentation Agent

By: /s/ Robert R. Wetteroff
    -----------------------------------------------
    Name:  Robert R. Wetteroff
           ----------------------------------------
    Title: Senior Vice President
           ----------------------------------------

MORGAN GUARANTY TRUST COMPANY OF NEW YORK, Individually and as Syndication Agent

By: /s/ John Kowalczuk
    -----------------------------------------------
    Name:  John Kowalczuk
           ----------------------------------------
    Title: Vice President
           ----------------------------------------

CREDIT LYONNAIS NEW YORK BRANCH

By: /s/ Philippe Soustra
    -----------------------------------------------
    Name:  Philippe Soustra
           ----------------------------------------
    Title: Senior Vice President
           ----------------------------------------
<PAGE>

BANK ONE, TEXAS, N.A.

By: /s/ Wm. Mark Cranmer
    -------------------------------------------
    Name:  Wm. Mark Cranmer
           ------------------------------------
    Title: Vice President
           ------------------------------------

PARIBAS

By: /s/ Marian Livingston
    -------------------------------------------
    Name:  Marian Livingston
           ------------------------------------
    Title: Vice President
           ------------------------------------

UNION BANK OF CALIFORNIA, N.A.

By: /s/ Gary Shekerjian
    -------------------------------------------
    Name:  Gary Shekerjian
           ------------------------------------
    Title: Assistant Vice President
           ------------------------------------
<PAGE>

                                  SCHEDULE 1

Chase Bank of Texas, N.A.
One Chase Manhattan Plaza, 8th Floor
New York, NY 10081
Attention: Muniram Appanna Agency Services

First Union National Bank
c/o First Union Corporation
1001 Fannin Street, Suite 2255
Houston, Texas 77002-6709
Attention: Ms. Vicki Crispens

Morgan Guaranty Trust
Company of New York
60 Wall Street
New York, New York 10260
Attention: Phillip McNeal

Credit Lyonnais New York Branch
c/o Credit Lyonnais
Houston Representative Office
1000 Louisiana, Suite 5360
Houston, Texas 77002
Attention: John M. Falbo

Bank One, Texas, N.A.
1717 Main Street
Dallas, Texas 75201
Attention: Mark Cranmer

Paribas
1200 Smith Street, Suite 3100
Houston, Texas 77002
Attention: Brian Malone

Union Bank of California, N.A.
4200 Lincoln Plaza
500 North Akard
Dallas, Texas 75201
Attention: Gary Shekerjian

cc:  Chase Securities, Inc.
     707 Travis Street, 5N86
     Houston, Texas 77002
     Attention: Robert C. Mertensotto<PAGE>

                                                                     EXHIBIT 4.1

                                 AMENDMENT TO RIGHTS AGREEMENT

          THIS AMENDMENT TO RIGHTS AGREEMENT (this "Amendment"), dated as of
March 1, 2000, is between TANDYCRAFTS, INC., a Delaware corporation (the
"Company"), and FIRST CHICAGO TRUST COMPANY OF NEW YORK (the "Rights Agent"), at
the direction of the Company.

          WHEREAS, the Company and CHASEMELLON SHAREHOLDER SERVICES, L.L.C., a
New Jersey limited liability company, a predecessor to the Rights Agent, entered
into a Rights Agreement dated as of May 19, 1997 (the "Rights Agreement");

          WHEREAS, the Rights Agent has accepted assignment of the Rights
Agreement and has agreed to assume each and every right, duty, obligation and
interest of ChaseMellon Shareholder Services, L.L.C. under the Rights Agreement;

          WHEREAS, Section 27 of the Rights Agreement permits the amendment of
                   ----------
the Rights Agreement by the Board of Directors of the Company;

          WHEREAS, pursuant to a resolution duly adopted on March 1, 2000, the
Board of Directors of the Company has adopted and authorized the amendment of
the Rights Agreement so that the Rights Agreement will, among other things, no
longer require certain action to be taken by "continuing directors";

          WHEREAS, the Board of Directors of the Company has resolved and
determined that such amendment is desirable and consistent with, and for the
purpose of fulfilling, the objectives of the Board of Directors in connection
with the original adoption of the Rights Agreement;

          NOW, THEREFORE, the Rights Agreement is hereby amended as follows:

1.        AMENDMENT OF SECTION 1.
          ----------------------

          Section 1(h) of the Rights Agreement is hereby amended in its entirety
          ------------
to read as follows:

                  "(h)  [intentionally left blank]."

All references in the Rights Agreement to "Continuing Directors" are deleted
mutatis mutandis.

          Section 1(o) of the Rights Agreement is hereby amended in its entirety
          ------------
to read as follows:

                  "(o)  "Requisite Majority" means, at any time, the affirmative
     vote of a majority of the directors then in office."
<PAGE>

2.        AMENDMENT OF SECTION 29.
          -----------------------

          Section 29 of the Rights Agreement is amended by deleting (i) each
          ----------
occurrence of the phrase "(with, where specifically provided for in this
Agreement, the concurrence of the Continuing Directors)" in the second and third
sentences of said section and (ii) the phrase "or the Continuing Directors" in
the third sentence of said section.

3.        AMENDMENT TO EXHIBIT B.
          ----------------------

          Exhibit B to the Rights Agreement is amended by (i) deleting the last
          ---------
sentence of the second paragraph and replacing such sentence with the following:

          "A majority of the directors may in their discretion vote to extend
          the Distribution Date."

and (ii) deleting the portion of the seventh paragraph that states "(including a
majority of the Continuing Directors)."

4.        EFFECTIVENESS.
          -------------

          This Amendment to the Rights Agreement shall be effective as of the
date of this Amendment, and all references to the Rights Agreement shall, from
and after such time, be deemed to be references to the Rights Agreement as
amended hereby.

5.        CERTIFICATION.
          -------------

          The undersigned officer of the Company certifies by execution hereof
that this Amendment is in compliance with the terms of Section 27 of the Rights
                                                       ----------
Agreement.

6.        MISCELLANEOUS.
          -------------

          This Amendment may be executed in any number of counterparts, each of
such counterparts shall for all purposes be deemed to be an original, and all
such counterparts shall together constitute but one and the same instrument.  If
any term, provision, covenant or restriction of this Amendment is held by a
court of competent jurisdiction or other authority to be invalid, illegal, or
unenforceable, the remainder of the terms, provisions, covenants and
restrictions of this Amendment shall remain in full force and effect and shall
in no way be affected, impaired or invalidated.
<PAGE>

          IN WITNESS WHEREOF, the parties hereto have caused this Amendment to
be duly executed as of the date and year first above written.

                                TANDYCRAFTS, INC.

                                By:     /s/ James D. Allen
                                        ------------------
                                Name:   James D. Allen
                                Title:  President and Chief Operating Officer

                                FIRST CHICAGO TRUST COMPANY OF NEW YORK, as
                                Rights Agent

                                By:     /s/ David Kang
                                        --------------
                                Name:   David Kang
                                Title:  Senior Account Manager

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