Document:

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                                                                     EXHIBIT 4.2

                           AMENDMENT NO. 1 AND WAIVER

     This Amendment No. 1 and Waiver dated as of November 21, 2001 ("Waiver")
is by and among the lenders party to the Second Amended and Restated Credit
Agreement described below ("Lenders"), Union Bank of California, N.A., as agent
for such Lenders ("Agent"), Edge Petroleum Corporation, a Delaware Corporation
("Parent"), Edge Petroleum Exploration Company, a Delaware corporation ("Edge
Exploration"), and Edge Petroleum Operation Company, Inc., a Texas corporation
("Edge Operating" and together with the Parent and Edge Exploration, referred
to collectively as the "Borrowers"), as borrowers under the Second Amended and
Restated Credit Agreement.

                                  INTRODUCTION

     A.   The Borrowers, the Agent and the Lenders are parties to the Second
Amended and Restated Credit Agreement dated as of October 6, 2000 (the "Credit
Agreement").

     B.   A judgment in excess of $500,000 has been rendered against Edge
Exploration in the suit titled Edge Petroleum Exploration Company, et al, vs.
BNP Petroleum Corporation, et al; Cause No. DC-00-58, which was filed in the
29th Judicial District Court, Duval County, Texas (the "Adverse Judgment").

     C.   The Borrower, the Agent and the Lenders wish to, subject to the terms
and conditions of this Waiver, (1) acknowledge the existence of certain
Defaults and Events of Default (each as defined in the Credit Agreement) as a
result of the Adverse Judgment, (2) provide for a waiver of such existing
Defaults and Events of Default, and (3) amend the Credit Agreement to extend
the Final Maturity Date (as defined in the Credit Agreement).

     THEREFORE, the Borrowers, the Agent and the Lenders hereby agree as
follows:

     Section 1. Definitions; References.  Unless otherwise defined in this
Waiver, each term used in this Waiver which is defined in the Credit Agreement
has the meaning assigned to such term in the Credit Agreement.

     Section 2. Acknowledgement of Defaults and Event of Defaults.  The
Borrowers hereby acknowledge the existence of the following Defaults and Events
of Defaults (the "Existing Defaults"): (a) any misrepresentation the Borrowers
may have made under Section 4.9 of the Credit Agreement prior to the date
hereof solely as a result of the existence of the Adverse Judgment; and (b) an
Event of Default arising under Section 7.1(g) of the Credit Agreement as a
result of the existence of the Adverse Judgment.

     Section 3. Waiver of Existing Defaults and Agreement of Lenders.  (a) The
Lenders hereby agree, subject to the terms of this Waiver, to waive the
Existing Defaults. The waiver by the Lenders described in the preceding
sentence is contingent upon the satisfaction of the conditions precedent set
forth below and is limited to the Existing Defaults. This waiver is limited to
the extent described herein and shall not be construed to be a consent to or a
permanent waiver of the Sections covered by the Existing Defaults or any other
terms,

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provisions, covenants, warranties or agreements contained in the Credit
Agreement or in any of the other Credit Documents. The Lenders reserve the
right to exercise any rights and remedies available to them in connection with
any other present or future defaults with respect to the Credit Agreement or
any other provision of any Loan Document.

     (b)   The Lenders also hereby agree that, as of the date hereof and subject
to the terms of this Waiver, the mere existence of the Adverse Judgement shall
not constitute a Material Adverse Effect under the Credit Agreement. The
agreement in the preceding sentence is limited to the existence of the Adverse
Judgement and shall not be construed to be an agreement that (i) any other event
or circumstance arising as a result of the existence of the Adverse Judgement
shall not constitute a Material Adverse Effect under the Credit Agreement or
(ii) the existence of any other adverse judgements occurring hereafter shall not
constitute a Material Adverse Effect under the Credit Agreement.

     Section 4.  Amendment.  The following term, which is defined in Section 1.2
of the Credit Agreement, is hereby amended in its entirety to read as follows:

     "Final Maturity Date" shall mean October 6, 2003.

     Section 5.  Representations and Warranties.  Each of the Borrowers
represents and warrants to the Agent and the Lenders that: (a) after giving
effect to this Waiver, all of the representations and warranties of the
Borrowers set forth in the Credit Agreement and in the other Loan Documents are
true and correct in all material respects as of the date of this Waiver, except
as a result of the transactions expressly permitted under such Credit Agreement
and Credit Documents and except to the extent that any such representation or
warranty relates solely to an earlier date, in which case it shall have been
true and correct in all material respects as of such earlier date; (b) the
execution, delivery and performance of this Waiver are within each of the
Borrower's corporate power and authority and have been duly authorized by
appropriate proceedings by each of the Borrowers, (c) this Waiver constitutes a
legal, valid and binding obligation of each of the Borrowers enforceable in
accordance with its terms, except as limited by applicable bankruptcy,
insolvency, reorganization, moratorium or similar laws affecting the rights of
creditors generally and general principles of equity; and (d) other than the
Existing Defaults that have been waived pursuant to this Waiver, no Default or
Event of Default has occurred and is continuing.

     Section 6.  Effectiveness.  This Waiver shall become effective, and the
waiver provisions provided for herein shall be effective as of the date of this
Waiver, upon satisfaction of the following conditions precedent: (a) the
Borrowers, the Agent and the Lenders shall have delivered duly and validly
executed originals (unless otherwise indicated) of this Waiver to the Agent;
(b) the representations and warranties in this Waiver shall be true and correct
in all material respects; (c) on the date of this Waiver, the Borrowers shall
have paid a waiver fee of $5,000 to the Agent for the account of the Lenders;
and (d) the Borrowers shall have paid all costs and expenses which have been
invoiced and are payable pursuant to Section 5.14 of the Credit Agreement.

     Section 7.  Effect on Loan Documents.  Each of the Borrowers, the Agent and
the Lenders does hereby adopt, ratify, and confirm the Credit Agreement, as
amended hereby, and
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acknowledges and agrees that the Credit Agreement, as amended hereby, is and
remains in full force and effect. Other than the waiver of the Existing Defaults
as expressly set forth Section 3 above, nothing herein shall act as a waiver of
any of the Agent's or Lender's rights under the Loan Documents, as amended,
including the waiver of any other Default or Event of Default, however
denominated. From and after the date hereof, all references to the Credit
Agreement and the Loan Documents shall mean such Credit Agreement and such Loan
Documents as amended by this Waiver. This Waiver is a Loan Document for the
purposes of the provisions of the other Loan Documents. Without limiting the
foregoing, any breach of representations, warranties, and covenants under this
Waiver shall be a Default or Event of Default, as applicable, under the Credit
Agreement.

     Section 8. Choice of Law.  This Waiver shall be governed by and construed
and enforced in accordance with the laws of the State of Texas without giving
effect to principles thereof relating to conflicts of laws.

     Section 9. Counterparts.  This Waiver may be signed in any number of
counterparts, each of which shall be an original and all of which taken together
shall constitute one and the same agreement.

     THIS WRITTEN AGREEMENT AND THE LOAN DOCUMENTS, AS DEFINED IN THE CREDIT
AGREEMENT, REPRESENT THE FINAL AGREEMENT AMONG THE PARTIES AND MAY NOT BE
CONTRADICTED BY EVIDENCE OF PRIOR, CONTEMPORANEOUS, OR SUBSEQUENT ORAL
AGREEMENTS OF THE PARTIES.

     THERE ARE NO UNWRITTEN ORAL AGREEMENTS BETWEEN THE PARTIES.

   [REMAINDER OF THIS PAGE INTENTIONALLY LEFT BLANK. SIGNATURE PAGE FOLLOWS.]

                                      -3-
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     EXECUTED as of the 21st day of November, 2001.

                                   UNION BANK OF CALIFORNIA, N.A., as Agent
                                   and as the sole Lender

                                   By:    /s/ DAMIEN MELBURGER
                                      -------------------------------
                                   Name:  Damien Melburger
                                        -----------------------------
                                   Title: Senior Vice President
                                         ----------------------------

                                   BORROWERS:

                                   EDGE PETROLEUM CORPORATION

                                   By:    /s/ MICHAEL G. LONG
                                      -------------------------------
                                          Michael G. Long
                                          Chief Financial Officer

                                   EDGE PETROLEUM EXPLORATION
                                   COMPANY

                                   By:    /s/ MICHAEL G. LONG
                                      -------------------------------
                                          Michael G. Long
                                          Chief Financial Officer

                                   EDGE PETROLEUM OPERATING
                                   COMPANY, INC.

                                   By:    /s/ MICHAEL G. LONG
                                      -------------------------------
                                          Michael G. Long
                                          Chief Financial Officer

                                      -4-<PAGE>
                                                                     EXHIBIT 4.6

                    [LETTERHEAD OF UNION BANK OF CALIFORNIA]

January 18, 2002

Edge Petroleum Corporation
Edge Petroleum Exploration Company
Edge Petroleum Operating Company, Inc.
2100 Texaco Heritage Plaza
Houston, Texas 77002
Attention: Mr. Mike Long

Gentlemen:

Reference is hereby made to that certain Second Amended and Restated Credit
Agreement in the amount of $25.0 million by and among Edge Petroleum
Corporation, Edge Petroleum Exploration Company and Edge Petroleum Operating
Company, Inc. as Borrowers and Union Bank of California, N.A. as Agent and
Lender dated as of October 6, 2000 (the "Credit Agreement"). All capitalized
terms herein shall have the meaning assigned to such terms in the Credit
Agreement unless otherwise defined herein.

The purpose of this letter is to inform you that the Agent and sole Lender has
redetermined the Borrowing Base and the amount of the monthly Borrowing Base
reduction pursuant to Section 2.10 of the Credit Agreement. Effective
immediately upon your execution of a counterpart of this letter and the return
thereof to the Agent, the Borrowing Base shall be in the amount of $18.0
million and the monthly Borrowing Base reduction shall be zero. Both such
figures shall be effective until the next redetermination thereof pursuant to
Section 2.10 of the Credit Agreement.

All other terms and conditions contained in the Credit Agreement remain
unchanged and in full force and effect.

If you are in agreement with forgoing please evidence your agreement by
executing this letter in the space provided and returning one fully-executed
counterpart to the undersigned.

Sincerely,

/s/ DAMIEN G. MELBURGER
------------------------
Damien G. Melburger
Senior Vice President

ACCEPTED AND AGREED
This 21 day of January, 2002

/s/ MICHAEL G. LONG
------------------------
Authorized Officer on behalf of Edge Petroleum Corporation,
Edge Petroleum Exploration Company and Edge Petroleum Operating Company, Inc.

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