Document:

<PAGE>

                                                                     EXHIBIT 4.1

                          SECOND SUPPLEMENTAL INDENTURE

         SECOND SUPPLEMENTAL INDENTURE dated as of September 16, 2002 (the
"SUPPLEMENTAL INDENTURE"), between CALLON PETROLEUM COMPANY, a Delaware
corporation (the "COMPANY"), having its principal office at 200 North Canal
Street, Natchez, Mississippi 39120, and AMERICAN STOCK TRANSFER & TRUST COMPANY,
a corporation duly authorized and existing under the laws of the state of New
York, as trustee (the "TRUSTEE").

         WHEREAS, there has heretofore been executed and delivered to the
Trustee an Indenture dated as of July 31, 1997 between the Company and the
Trustee (as the same has been amended or supplemented from time to time by one
or more indentures supplemental thereto entered into pursuant to the applicable
provisions thereof, the "INDENTURE"), providing for the issuance of the
Company's 10.125% Senior Subordinated Notes due 2002 (the "NOTES");

         WHEREAS, with respect to the Notes of all Holders other than the
Consenting Holders (defined below), Money in the amount necessary to pay all
principal, interest, premium, and other amounts due and owing at Maturity under
such Notes has been deposited with the Trustee in trust for such Holders;

         WHEREAS, there are now outstanding under the Indenture Notes in the
aggregate principal amount of $22,915,000;

         WHEREAS, the Company has received consents from all Holders of
Outstanding Notes ("CONSENTING HOLDERS") to certain amendments to the Indenture;

         WHEREAS, Section 902 of the Indenture provides that the Company and the
Trustee may amend the Indenture with the written consent of the Holders (as
defined in the Indenture) of at least a majority in principal amount of the
Notes then outstanding, or with respect to certain amendments, with the consent
of the Holder of each Outstanding Note;

         WHEREAS, the Company desires to amend certain provisions of the
Indenture, as set forth in Article II hereof;

         WHEREAS, the Holder of each Outstanding Note is a Consenting Holder
that has consented to the amendments effected by this Supplemental Indenture;
and

         WHEREAS, all matters necessary to make this Supplemental Indenture a
valid agreement, in accordance with its terms, have been done.

         NOW THEREFORE, this Supplemental Indenture witnesseth that, for and in
consideration of the premises, the Company and the Trustee agree as follows for
the equal and ratable benefit of the Holders of the Notes:

<PAGE>

                                    ARTICLE I
                                  EFFECTIVENESS

         SECTION 1.1. Effectiveness. This Supplemental Indenture shall become
effective as of the date hereof.

                                   ARTICLE II
                             AMENDMENTS TO INDENTURE

         SECTION 2.1. Amendments to Indenture.

         (a) The definition of Redemption Price in Section 101 is hereby amended
in its entirety to read as follows:

                  "'Redemption Price', with respect to any Note or portion
                  thereof to be redeemed, means 100% of the principal amount of
                  the Note to be redeemed."

         (b) Section 1007(a)(ii) of the Indenture is hereby amended in its
entirety to read as follows:

                  "The Interest Coverage Ratio would have been less than (x) 1.1
                  to 1.0 for the period commencing September 15, 2002 through
                  December 31, 2003, or (y) 2.4 to 1.0 for all periods
                  commencing January 1, 2004."

         (c) Section 1101 of the Indenture is hereby amended in its entirety to
read as follows:

                  "The Company may, at its option, redeem all or any part of the
                  Notes at any time, at the Redemption Price, together with
                  interest accrued to the Redemption Date. Redemption of Notes
                  at the option of the Company as permitted hereby shall be made
                  in accordance with the terms of such Notes and this Article."

         (d) The Form of Exchange Note attached as Exhibit 2 to Appendix A of
the Indenture is hereby amended in its entirety by deleting the Form of Exchange
Note (Exhibit 2 to Appendix A) and replacing such Form of Exchange Note with the
Form of Amended Note (the "AMENDED NOTE") attached hereto as Exhibit I. The
Trustee shall authenticate and deliver Amended Notes and exchange such Amended
Notes for any Notes outstanding on the date hereof that are held by Consenting
Holders. Such Amended Notes shall be deemed Notes for purposes of the Indenture.

                                   ARTICLE III
                                  MISCELLANEOUS

         SECTION 3.1 Instruments To Be Read Together. This Supplemental
Indenture is an indenture supplemental to and in implementation of the
Indenture, and said Indenture and this Supplemental Indenture shall henceforth
be read together:

         SECTION 3.2 Confirmation. The Indenture as amended and supplemented by
this Supplemental Indenture is in all respects confirmed and preserved.

<PAGE>

         SECTION 3.3 Terms Defined. Capitalized terms used in this Supplemental
Indenture and not otherwise defined herein shall have the respective meanings
set forth in the Indenture.

         SECTION 3.4 Headings. The headings of the Articles and Sections of this
Supplemental Indenture have been inserted for convenience of reference only, and
are not to be considered a part hereof and shall in no way modify or restrict
any of the terms and provisions hereof.

         SECTION 3.5 Governing Laws. The laws of the State of New York shall
govern this Supplemental Indenture.

         SECTION 3.6 Counterparts. This Supplemental Indenture may be executed
in any number of counterparts, each of which so executed shall be deemed to be
an original, but all such counterparts shall together constitute but one and the
same instrument.

         SECTION 3.7 Compliance with the Trust Indenture Act. This Supplemental
Indenture shall be interpreted to comply in every respect with the Trust
Indenture Act of 1939, as amended (the "TIA"). If any provision of this
Supplemental Indenture limits, qualifies or conflicts with the duties imposed by
the TIA, the imposed duties shall control.

         SECTION 3.8 Acceptance by Trustee. The Trustee accepts the amendments
to the Indenture effected by this Supplemental Indenture and agrees to execute
the trusts created by the Indenture as hereby amended, but upon the terms and
conditions set forth in the Indenture.

         SECTION 3.9 Responsibility of Trustee. The recitals contained herein
shall be taken as the statements of the Company, and the Trustee assumes no
responsibility for their correctness. The Trustee makes no representations as to
the validity or sufficiency of this Supplemental Indenture, except that the
Trustee is duly authorized to execute and deliver this Supplemental Indenture.

         IN WITNESS WHEREOF, the parties hereto have caused this First
Supplemental Indenture to be duly executed, all as of the date first written
above.

                                             CALLON PETROLEUM COMPANY

                                             By: /s/ John Weatherly
                                                 -------------------------------
                                                 John Weatherly, Senior Vice
                                                 President and Chief Financial
                                                 Officer

                                             AMERICAN STOCK TRANSFER & TRUST
                                             COMPANY

                                             By: /s/ Herbert J. Lemmer
                                                --------------------------------
                                             Name: Herbert J. Lemmer
                                                  ------------------------------
                                             Title: Vice President
                                                   -----------------------------

<PAGE>

                                    EXHIBIT I

                                                                       EXHIBIT 3
                                                                   TO APPENDIX A

                         [FORM OF FACE OF AMENDED NOTE]

                            CALLON PETROLEUM COMPANY

No._____                                                     CUSIP No.__________

         [Global Notes Legend]

         UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF
THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), NEW YORK, NEW
YORK, TO THE COMPANY OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR
PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR
SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY
PAYMENT IS MADE TO CEDE & CO., OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN
AUTHORIZED REPRESENTATIVE OF DTC) ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR
VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED
OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

         TRANSFERS OF THIS GLOBAL NOTE SHALL BE LIMITED TO TRANSFERS IN WHOLE,
BUT NOT IN PART, TO NOMINEES OF DTC OR TO A SUCCESSOR THEREOF OR SUCH
SUCCESSOR'S NOMINEE AND TRANSFERS OF PORTIONS OF THIS GLOBAL NOTE SHALL BE
LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE RESTRICTIONS SET FORTH IN THE
INDENTURE REFERRED TO ON THE REVERSE HEREOF.

         THIS GLOBAL NOTE IS EXCHANGEABLE FOR NOTES IN DEFINITIVE, FULLY
REGISTERED FORM, WITHOUT INTEREST COUPONS, IF (A) DTC NOTIFIES THE COMPANY THAT
IT IS UNWILLING OR UNABLE TO CONTINUE AS DEPOSITORY FOR THIS GLOBAL NOTE OR IF
AT ANY TIME DTC CEASES TO BE A "CLEARING AGENCY" REGISTERED UNDER THE SECURITIES
EXCHANGE ACT OF 1934, AS AMENDED, AND A SUCCESSOR DEPOSITORY IS NOT APPOINTED BY
THE COMPANY WITHIN 90 DAYS OF SUCH NOTICE, (B) THE COMPANY EXECUTES AND DELIVERS
TO THE TRUSTEE A NOTICE THAT THIS GLOBAL NOTE SHALL BE TRANSFERABLE,

<PAGE>

REGISTRABLE AND EXCHANGEABLE, AND SUCH TRANSFER SHALL BE REGISTRABLE, OR (C) AN
EVENT OF DEFAULT (AS HEREINAFTER DEFINED) HAS OCCURRED AND IS CONTINUING WITH
RESPECT TO THE NOTES.

       GLOBAL NOTE Representing 10.125% Senior Subordinated Notes due 2004

         CALLON PETROLEUM COMPANY, a Delaware corporation, hereby promises to
pay to CEDE & CO., or registered assigns, the principal sum indicated on
Schedule A hereof, on July 31, 2004.

         Interest Payment Dates: December 15, March 15, June 15 and September
15, commencing December 15, 2002.

         Record Dates: December 1, March 1, June 1 and September 1.

         Additional provisions of this Note are set forth on the other side of
this Note.

         IN WITNESS WHEREOF, CALLON PETROLEUM COMPANY has caused this instrument
to be duly executed under its corporate seal.

Dated:

CALLON PETROLEUM COMPANY                     [CORPORATE SEAL]

By:
   ----------------------------------
     Name:
          ---------------------------
     Title:
           --------------------------

Attest:
       ------------------------------
        Secretary

                     TRUSTEE'S CERTIFICATE OF AUTHENTICATION

         AMERICAN STOCK TRANSFER & TRUST COMPANY, as Trustee, certifies that
this is one of the Notes referred to in the Indenture.

By:
   ----------------------------------
   Authorized Signatory

<PAGE>

                     [FORM OF REVERSE SIDE OF AMENDED NOTE]

                    10.125% Senior Subordinated Note due 2004

         1. Interest. Callon Petroleum Company, a Delaware corporation (such
corporation, and its successors and assigns under the Indenture hereinafter
referred to, being herein called the "Company"), promises to pay interest on the
principal amount of this Note at the rate per annum shown above. The Company
will pay interest quarterly on March 15, June 15, September 15, and December 15
of each year, and on July 31, 2004. Interest on the Notes will accrue from the
most recent date to which interest has been paid or, if no interest has been
paid, from the Issue Date. Interest will be computed on the basis of a 360-day
year of twelve 30-day months.

         2. Method of Payment. The Company will pay interest on the Notes
(except defaulted interest) to the Persons who are registered holders of Notes
at the close of business on March 1, June 1, September 1 or December 1
immediately preceding the interest payment date even if Notes are canceled after
the record date and on or before the interest payment date. Holders must
surrender Notes to a Paying Agent to collect principal payments. The Company
will pay principal and interest in money of the United States that at the time
of payment is legal tender for payment of public and private debts. Payments in
respect of the Notes represented by a Global Note (including principal, premium
and interest) will be made by wire transfer of immediately available funds to
the accounts specified by The Depository Trust Company, but, at the option of
the Company, interest may be paid by check mailed to the registered Holders at
their registered addresses. The Company will make all payments in respect of a
certificated Note (including principal, premium and interest), by mailing a
check to the registered address of each Holder thereof; provided, however, that
payments on the Notes may also be made, in the case of a Holder of at least
$1,000,000 aggregate principal amount of Notes, by wire transfer to a U.S.
dollar account maintained by the payee with a bank in the United States if such
Holder elects payment by wire transfer by giving written notice to the Trustee
or the Paying Agent to such effect designating such account no later than 30
days immediately preceding the relevant due date for payment (or such other date
as the Trustee may accept in its discretion).

         3. Paying Agent and Registrar. Initially, American Stock Transfer &
Trust Company, a New York corporation ("Trustee"), will act as Paying Agent and
Note Registrar. The Company may appoint and change any Paying Agent, Note
Registrar or co-registrar without notice. The Company or any of its domestically
incorporated Wholly Owned Restricted Subsidiaries may act as Paying Agent, Note
Registrar or co-registrar.

         4. Indenture. The Company issued the Notes under an Indenture dated as
of July 31, 1997, as amended by the First Supplemental Indenture dated as of
June 26, 2002 and the Second Supplemental Indenture dated as of September 16,
2002 (as such may be amended from time to

<PAGE>

time, the "Indenture"), between the Company and the Trustee. The terms of the
Notes include those stated in the Indenture and those made part of the Indenture
by reference to the Trust Indenture Act of 1939 (15 U.S.C. Sections
77aaa-77bbbb) as in effect on the date of the Indenture (the "Act"). Terms
defined in the Indenture and not defined herein have the meanings ascribed
thereto in the Indenture. The Notes are subject to all such terms, and Holders
are referred to the Indenture and the Act for a statement of those terms.

         The Notes are unsecured senior subordinated obligations of the Company
limited to up to $36,000,000 aggregate principal amount at any one time
Outstanding. This Note is one of the Amended Notes referred to in the Indenture.

         5. Denominations; Transfer; Exchange. The Notes are in registered form
without coupons in denominations of $1,000 and whole multiples of $1,000. A
Holder may transfer or exchange Notes in accordance with the Indenture. Upon any
transfer or exchange, the Registrar and the Trustee may require a Holder, among
other things, to furnish appropriate endorsements or transfer documents and to
pay any taxes required by law or permitted by the Indenture. The Registrar need
not register the transfer of or exchange any Notes selected for redemption
(except, in the case of a Note to be redeemed in part, the portion of the Note
not to be redeemed) or to transfer or exchange any Notes for a period of 15 days
prior to a selection of Notes to be redeemed or 15 days before an interest
payment date.

         6. Subordination. The indebtedness of the Company evidenced by the
Notes, including the principal thereof and interest thereon (including
post-default interest), is expressly subordinated, to the extent and to the
manner set forth in the Indenture, in right of payment to the prior payment in
full of all of the Company's obligations to holders of Senior Indebtedness. Each
Holder of Notes, by acceptance thereof, (a) agrees to and shall be bound by such
provisions of the Indenture and all other provisions of the Indenture; (b)
authorizes and directs the Trustee to take such action on such Holder's behalf
as may be necessary or appropriate to effectuate the subordination of the Notes
as provided in the Indenture; and (c) appoints the Trustee as such Holder's
attorney-in-fact for any and all such purposes.

         7. Optional Redemption. The Notes are subject to redemption, at the
option of the Company, in whole or in part, at any time, upon not less than 30
or more than 60 days' notice at the Redemption Price, together in the case of
any such redemption with accrued and unpaid interest, if any, to the Redemption
Date, all as provided in the Indenture.

In the case of any redemption of Notes, interest installments whose Stated
Maturity is on or prior to the Redemption Date will be payable to Holders of
such Notes, or one or more Predecessor Notes. Notes (or portions thereof) for
whose redemption and payment provision is made in accordance with the Indenture
shall cease to bear interest from and after the Redemption Date. In the event of
redemption or purchase of this Note in part only, a new Note or Notes for the
unredeemed or unpurchased portion hereof shall be issued in the name of the
Holder hereof upon

<PAGE>

the cancellation hereof. If fewer than all Notes are redeemed, the Trustee will
select the Notes to be redeemed by lot or such other method as the Trustee may
deem fair and appropriate.

         8. Notice of Redemption. Notice of redemption shall be given to the
Holders of Notes to be redeemed by mailing a notice of such redemption not less
than 30 or more than 60 days prior to the Redemption Date at their addresses as
they shall appear on the Note Register, all as provided in the Indenture.

         If this Note (or a portion hereof) is duly called for redemption and
funds for payment are duly provided, this Note (or such portion hereof) shall
cease to bear interest from and after such Redemption Date.

         Interest installments whose Stated Maturity is on the Redemption Date
will be payable to the Holders of such Notes, or one or more Predecessor Notes,
of record at the close of business on the relevant Regular Record Date referred
to on the face hereof, all as provided in the Indenture. In the event of
redemption or repayment of this Note in part only, a new Note or Notes for the
unredeemed or unrepaid portion hereof shall be issued in the name of the Holder
hereof upon the surrender hereof.

         9. Defaults and Remedies. Except as may be provided in the Indenture,
if an Event of Default with respect to the Notes shall occur and be continuing,
the Trustee or the Holders of not less than 25% in aggregate principal amount of
the Outstanding Notes may declare the principal of all the Notes due and payable
in the manner and with the effect provided in the Indenture. The Indenture
provides that such declaration and its consequences may, in certain events, be
annulled by the Holders of a majority in aggregate principal amount of the
Outstanding Notes.

         10. Discharge and Defeasance. The Indenture contains provisions for (i)
defeasance at any time of the entire indebtedness of the Company on this Note
and (ii) discharge from certain restrictive covenants and the related Defaults
and Events of Default, upon compliance by the Company with certain conditions
set forth therein, which provisions apply to this Note.

         11. Amendment and Waiver. The Indenture permits, with certain
exceptions as therein provided, the amendment thereof and the modification of
the rights and obligations of the Company and the rights of the Holders of the
Notes under the Indenture at any time by the Company and the Trustee with the
consent of the Holders of a majority in aggregate principal amount of the Notes
at the time Outstanding. The Indenture also contains provisions permitting the
Holders of specified percentages in aggregate principal amount of the Notes at
the time Outstanding, on behalf of the Holders of all Notes, to waive compliance
by the Company with certain provisions of the Indenture and certain past
defaults under the Indenture and their consequences. Any such consent or waiver
by the Holder of this Note shall be conclusive and binding upon such Holder and
upon all future Holders of this Note and of any Note issued upon

<PAGE>

the registration of transfer hereof or in exchange herefor or in lieu hereof,
whether or not notation of such consent or waiver is made upon this Note.
Without the consent of any Holder, the Company and the Trustee may amend or
supplement the Indenture or the Notes to cure any ambiguity, defect or
inconsistency, to provide for uncertificated Notes in addition to or in place of
certificated Notes and to make certain other specified changes and other changes
that do not adversely affect the interests of any Holder.

         12. Obligations Absolute. No reference herein to the Indenture and no
provisions of this Note or of the Indenture shall alter or impair the obligation
of the Company, which is absolute and unconditional, to pay the principal of and
interest on this Note at the times, places and rate, and in the coin or
currency, herein prescribed.

         13. No Recourse Against Others. A director, officer, employee,
incorporator, shareholder or Affiliate of the Company, as such, past, present or
future shall not have any personal liability under this Note or the Indenture by
reason of his or its status as such director, officer, employee, incorporator,
shareholder or Affiliate, or any liability for any obligations of the Company
under the Notes or the Indenture or for any claim based on, in respect of, or by
reason of such obligations or their creation. Each Holder, by accepting this
Note, waives and releases all such liability. Such waiver and release are part
of the consideration for the issuance of this Note.

         14. Persons Deemed Owners. Prior to the due presentment of this Note
for registration of transfer or exchange, the Company, the Trustee and any agent
of the Company or the Trustee may treat the Person in whose name this Note is
registered as the owner hereof for all purposes, whether or not this Note be
overdue, and neither the Company, the Trustee, nor any such agent shall be
affected by notice to the contrary.

         15. Definitions. All terms used in this Note which are defined in the
Indenture shall have the meanings assigned to them in the Indenture.

         16. CUSIP Numbers. Pursuant to a recommendation promulgated by the
Committee on Uniform Note Identification Procedures, the Company has caused
CUSIP numbers to be printed on the Notes as a convenience to the Holders
thereof. No representation is made as to the accuracy of such numbers as printed
on the Notes and reliance may be placed only on the other identifying
information printed hereon.

         17. Governing Law. This Note shall be governed by and construed in
accordance with the laws of the State of New York.

         Each Holder of a Note covenants and agrees by such Holder's acceptance
thereof to comply with and be bound by the foregoing provisions.

<PAGE>

         The Company will furnish to any Holder upon written request and without
charge a copy of the Indenture. Requests may be made to the Company at 200 North
Canal Street, Natchez, Mississippi 39120.

<PAGE>

                                 Assignment Form

To assign this Note, fill in the form below:

I or we assign and transfer this Note to

---------------------------------------------------------------------
(Print or type assignee's name, address and zip code)

---------------------------------------------------------------------
(Insert assignee's social security or tax I.D. No.)

and irrevocably appoint __________________________________ agent to transfer
this Note on the books of the Company. The agent may substitute another to act
for him.

Signature:
           ----------------------------------

Date:
      ---------------------------------------

Sign exactly as your name appears on the other side of this Note.

Signature Guarantee:
                     ---------------------------------------------
                            (Signature must be guaranteed)

Notice: Signature(s) must be guaranteed by an institution which is a participant
in the Securities Transfer Agent Medallion Program ("STAMP") or similar program.

<PAGE>

                        [TO BE ATTACHED TO GLOBAL NOTES]

                                                                      Schedule A

         SCHEDULE OF INCREASES OR DECREASES IN GLOBAL NOTE

         The initial principal amount at maturity of this Global Note shall be
$__________. The following increases or decreases in this Global Note have been
made:

<Table>
<Caption>
                                                                    Principal Amount of
                  Amount of decrease       Amount of increase         this Global Note       Signature of authorized
   Date of        in principal amount      in principal amount    following such increase    signatory of Trustee a
   Exchange       of this Global Note      of the Global Note           or decrease           Securities Custodian
   --------       -------------------      -------------------    -----------------------    -----------------------
<S>               <C>                      <C>                    <C>                        <C>

</Table><PAGE>
                                                                    EXHIBIT 10.1

                          REGISTRATION RIGHTS AGREEMENT

         This REGISTRATION RIGHTS AGREEMENT dated September [____], 2002 (the
"Agreement") is entered into by and among Nuevo Energy Company, a Delaware
corporation (the "Company"), and Yorktown Energy Partners III, L.P., a Delaware
limited partnership, Yorktown Energy IV, L.P., a Delaware limited partnership,
Yorktown Partners LLC, a Delaware limited liability company, SAFIC S.A., a Swiss
corporation, Charles de Mestral, J. Ross Craft, Montana Oil and Gas, Inc., David
A. Badley, James S. Scott, Glenn Reed, Doug Allison, and Mohamed Yaich (together
with their successors or assigns, the "Stockholders").

         The Company and the Stockholders are parties to the Agreement and Plan
of Merger dated September [____], 2002 (the "Merger Agreement"), which provides
for the Merger of Athanor Resources, Inc., a Delaware corporation, with and into
the Company's wholly owned subsidiary ("Merger Sub"). As an inducement to the
Stockholders to enter into the Merger Agreement, the Company has agreed to
provide to the Stockholders and their direct and indirect transferees the
registration rights set forth in this Agreement. The execution and delivery of
this Agreement is a condition to the closing under the Merger Agreement.

         In consideration of the foregoing, the parties hereto agree as follows:

         1. Definitions. As used in this Agreement, the following terms shall
have the following meanings:

         "Business Day" shall mean any day that is not a Saturday, Sunday or
other day on which commercial banks in the State of Texas are authorized or
required by law to remain closed.

         "Closing Date" shall mean the Closing Date as defined in the Merger
Agreement.

         "Company" shall have the meaning set forth in the preamble and shall
also include the Company's successors.

          "Effectiveness Period" shall have the meaning set forth in Section
2(a) hereof.

         "Exchange Act" shall mean the Securities Exchange Act of 1934, as
amended from time to time.

          "Holders" shall mean the Stockholders, for so long as they own any
Registrable Securities, and each of their successors, assigns and direct and
indirect transferees who become registered owners of Registrable Securities.

          "Majority Holders" shall mean the holders of a majority of the
aggregate principal amount of outstanding Registrable Securities then-held by
Holders.

         "Merger Agreement" shall have the meaning set forth in the preamble.

         "Person" shall mean an individual, partnership, limited liability
company, corporation, trust or unincorporated organization, or a government or
agency or political subdivision thereof.

         "Prospectus" shall mean the prospectus included in a Shelf Registration
Statement, including any preliminary prospectus, and any such prospectus as
amended or supplemented by any prospectus supplement, including a prospectus
supplement with respect to the terms of the offering of any portion of the
Registrable Securities covered by a Shelf Registration Statement, and by all
other amendments and supplements to such prospectus, including post-effective
amendments, and in each case including any document incorporated by reference
therein.

<PAGE>

          "Registrable Securities" shall mean the Securities; provided that the
Securities shall cease to be Registrable Securities (i) when a Shelf
Registration Statement with respect to such Securities has been declared
effective under the Securities Act and such Securities have been disposed of
pursuant to such Shelf Registration Statement, (ii) when such Securities are
eligible to be sold pursuant to Rule 144(k) (or any similar provision then in
force, but not Rule 144A) under the Securities Act or (iii) when such Securities
cease to be outstanding.

         "Registration Expenses" shall mean any and all expenses incurred by the
Company with this Agreement, including without limitation: (i) all SEC, stock
exchange or National Association of Securities Dealers, Inc. registration and
filing fees, (ii) all fees and expenses incurred in connection with compliance
with state securities or blue sky laws, (iii) all expenses of any Persons in
preparing or assisting in preparing, word processing, printing and distributing
any Shelf Registration Statement, any Prospectus and any amendments or
supplements thereto, any underwriting agreements, securities sales agreements or
other similar agreements and any other documents relating to the performance of
and compliance with this Agreement, (iv) the fees and disbursements of counsel
for the Company and, in the case of a Shelf Registration Statement, the
reasonable fees and disbursements of one counsel for the Holders (which counsel
shall be selected by the Majority Holders and which counsel may also be counsel
for the Stockholders), and (v) the fees and disbursements of the independent
public accountants of the Company, including the expenses of any special audits
or "comfort" letters required by or incident to the performance of and
compliance with this Agreement, but excluding fees and expenses of counsel to
the underwriters or the Holders and underwriting discounts and commissions and
transfer taxes, if any, relating to the sale or disposition of Registrable
Securities by a Holder.

         "SEC" shall mean the Securities and Exchange Commission.

         "Securities" shall mean the Company's common stock.

         "Securities Act" shall mean the Securities Act of 1933, as amended from
time to time.

         "Shelf Registration Statement" shall mean a "shelf" registration
statement of the Company pursuant to the provisions of Section 2(a) hereof that
covers all the Registrable Securities (but no other securities unless approved
by the Holders whose Registrable Securities are to be covered by such Shelf
Registration Statement) on an appropriate form under Rule 415 under the
Securities Act, or any similar rule that may be adopted by the SEC, and all
amendments and supplements to such registration statement, including
post-effective amendments, in each case including the Prospectus contained
therein, all exhibits thereto and any document incorporated by reference
therein.

         "Stockholder" shall have the meaning set forth in the preamble.

         "Underwritten Offering" shall mean an offering in which Registrable
Securities are sold to one or more underwriters for reoffering to the public.

         2. Registration Under the Securities Act.

         (a) The Company shall use its reasonable best efforts to cause to be
filed, as soon as practicable after the Closing Date (and in no event later than
the 45th day following the Closing Date), a Shelf Registration Statement
providing for the sale of all the Registrable Securities by the Holders thereof
and to use its reasonable best efforts to have such Shelf Registration Statement
declared effective by the SEC.

         The Company agrees to use its reasonable best efforts to keep the Shelf
Registration Statement continuously effective until the earlier of (i) the date
on which no Registrable Securities are held by a Holder or (ii) the fifth
anniversary of the date after which the Shelf Registration Statement is
initially declared effective by

                                       2
<PAGE>

the SEC, provided that should the effectiveness of the Shelf Registration
Statement be suspended for any reason, the period of such suspension will not
count for purposes of determining the fifth anniversary of the initial effective
date, and such determination and calculation shall resume upon the Shelf
Registration Statement being deemed effective (the "Effectiveness Period"). The
Company further agrees to supplement or amend the Shelf Registration Statement
and the related Prospectus if required by the rules, regulations or instructions
applicable to the registration form used by the Company for such Shelf
Registration Statement or by the Securities Act or by any other rules and
regulations thereunder for shelf registration or if reasonably requested by any
Holder to include information with respect to such Holder to facilitate sales of
such Holder's Registrable Securities, and to use its reasonable best efforts to
cause any such amendment to become effective and such Shelf Registration
Statement and Prospectus to become usable as soon as thereafter practicable. The
Company agrees to furnish to the Holders of Registrable Securities copies of any
such supplement or amendment promptly after its being used or filed with the
SEC.

         (b) The Company shall pay all Registration Expenses in connection with
the registration pursuant to Section 2(a) hereof. Each Holder shall pay its
pro-rata portion of all underwriting discounts and commissions and transfer
taxes, if any, relating to the sale or disposition of such Holder's Registrable
Securities pursuant to the Shelf Registration Statement.

         (c) A Shelf Registration Statement pursuant to Section 2(a) hereof will
not be deemed to have become effective unless it has been declared effective by
the SEC.

         (d) Without limiting the remedies available to the Stockholders and the
Holders, the Company acknowledges that any failure by the Company to comply with
its obligations under Section 2(a) hereof may result in material irreparable
injury to the Stockholders or the Holders for which there is no adequate remedy
at law, that it will not be possible to measure damages for such injuries
precisely and that, in the event of any such failure, the Stockholders or any
Holder may obtain such relief as may be required to specifically enforce the
Company's obligations under Section 2(a) hereof.

         3. Registration Procedures. In connection with its obligations pursuant
to Section 2(a) hereof, the Company shall as expeditiously as possible:

                  (a) (i) prepare and file with the SEC a Shelf Registration
         Statement on the appropriate form under the Securities Act, which form
         (A) shall be selected by the Company, (B) shall be available for the
         sale of the Registrable Securities by the selling Holders thereof and
         (C) shall comply as to form in all material respects with the
         requirements of the applicable form and include all financial
         statements required by the SEC to be filed therewith; and (ii) use its
         reasonable best efforts to cause such Shelf Registration Statement to
         become effective and remain effective for the applicable period in
         accordance with Section 2 hereof;

                  (b) prepare and file with the SEC such amendments and
         post-effective amendments to such Shelf Registration Statement as may
         be necessary to keep such Shelf Registration Statement effective
         throughout the Effectiveness Period and cause each Prospectus to be
         supplemented by any required prospectus supplement and, as so
         supplemented, to be filed pursuant to Rule 424 under the Securities
         Act; and keep each Prospectus current during the period described in
         Section 4(3) of and Rule 174 under the Securities Act that is
         applicable to transactions by brokers or dealers with respect to the
         Registrable Securities;

                  (c) furnish to each Holder of Registrable Securities, to
         counsel for the Stockholders, to counsel for such Holders and to each
         underwriter of an Underwritten Offering of Registrable Securities, if
         any, without charge, as many copies of each Prospectus, including each
         preliminary Prospectus, and

                                       3
<PAGE>

         any amendment or supplement thereto, in order to facilitate the public
         sale or other disposition of the Registrable Securities thereunder; and
         the Company consents to the use of such Prospectus and any amendment or
         supplement thereto in accordance with applicable law by each of the
         selling Holders of Registrable Securities and any such underwriters in
         connection with the offering and sale of the Registrable Securities
         covered by and in the manner described in such Prospectus or any
         amendment or supplement thereto in accordance with applicable law;

                  (d) use its reasonable best efforts to register or qualify the
         Registrable Securities under all applicable state securities or blue
         sky laws of such jurisdictions as any Holder of Registrable Securities
         covered by a Shelf Registration Statement shall reasonably request in
         writing by the time the applicable Shelf Registration Statement is
         declared effective by the SEC; cooperate with the Holders in connection
         with any filings required to be made with the National Association of
         Securities Dealers, Inc.; and do any and all other acts and things that
         may be reasonably necessary or advisable to enable each Holder to
         complete the disposition in each such jurisdiction of the Registrable
         Securities owned by such Holder; provided that the Company shall not be
         required to (i) qualify as a foreign corporation or other entity or as
         a broker or dealer in securities in any such jurisdiction where it
         would not otherwise be required to so qualify, (ii) file any general
         consent to service of process in any such jurisdiction or (iii) subject
         itself to taxation in any such jurisdiction if it is already not so
         subject;

                  (e) notify each Holder of Registrable Securities, counsel for
         such Holders and counsel for the Stockholders promptly and, if
         requested by any such Holder or counsel, confirm such advice in writing
         (i) when a Shelf Registration Statement has become effective and when
         any post-effective amendment thereto has been filed and becomes
         effective, (ii) (A) of any request by the SEC or any state securities
         authority for amendments or (B) supplements to a Shelf Registration
         Statement and Prospectus or for additional information after the Shelf
         Registration Statement has become effective, (iii) of the issuance by
         the SEC or any state securities authority of any stop order suspending
         the effectiveness of a Shelf Registration Statement or the initiation
         of any proceedings for that purpose, (iv) if, between the effective
         date of a Shelf Registration Statement and the closing of any sale of
         Registrable Securities covered thereby, (A) the representations and
         warranties of the Company contained in any underwriting agreement,
         securities sales agreement or other similar agreement, if any, relating
         to an offering of such Registrable Securities cease to be true and
         correct in all material respects or (B) if the Company receives any
         notification with respect to the suspension of the qualification of the
         Registrable Securities for sale in any jurisdiction or the initiation
         of any proceeding for such purpose, (v) of the happening of any event
         during the period of the Shelf Registration Statement is effective that
         makes any statement made in such Shelf Registration Statement or the
         related Prospectus untrue in any material respect or that requires the
         making of any changes in such Shelf Registration Statement or
         Prospectus in order to make the statements therein not misleading and
         (vi) of any determination by the Company that a post-effective
         amendment to a Shelf Registration Statement would be appropriate;

                  (f) use its reasonable best efforts to obtain the withdrawal
         of any order suspending the effectiveness of a Shelf Registration
         Statement at the earliest possible moment and provide immediate notice
         to each Holder of the withdrawal of any such order;

                  (g) furnish to each Holder of Registrable Securities, without
         charge, at least one conformed copy of such Shelf Registration
         Statement and any post-effective amendment thereto (without any
         documents incorporated therein by reference or exhibits thereto, unless
         requested);

                  (h) cooperate with the selling Holders of Registrable
         Securities to facilitate the timely preparation and delivery of
         certificates representing Registrable Securities to be sold and not
         bearing any restrictive legends and enable such Registrable Securities
         to be issued in such denominations and

                                       4
<PAGE>

         registered in such names as the selling Holders may reasonably request
         at least one Business Day prior to the closing of any sale of
         Registrable Securities;

                  (i) upon the occurrence of any event contemplated by Section
         3(e)(v) and 3(e)(vi) hereof, use its reasonable best efforts to prepare
         and file with the SEC any required supplement or post-effective
         amendment to the Shelf Registration Statement or the related Prospectus
         or any document incorporated therein by reference or file any other
         required document so that, as thereafter delivered to purchasers of the
         Registrable Securities, such Prospectus will not contain any untrue
         statement of a material fact or omit to state a material fact necessary
         to make the statements therein, in the light of the circumstances under
         which they were made, not misleading; and the Company shall notify the
         Holders of Registrable Securities to suspend use of the Prospectus as
         promptly as practicable after the occurrence of such an event, and such
         Holders hereby agree to suspend use of the Prospectus until the Company
         has amended or supplemented the Prospectus to correct such misstatement
         or omission;

                  (j) a reasonable time prior to the filing of any Shelf
         Registration Statement, any Prospectus, any amendment to a Shelf
         Registration Statement or amendment or supplement to a Prospectus,
         provide copies of such document to the Stockholders or Holders and
         their counsel and make such of the representatives of the Company as
         shall be reasonably requested by the Stockholders or Holders or their
         counsel reasonably available for discussion of such document; and the
         Company shall not, at any time after initial filing of a Shelf
         Registration Statement, file any Prospectus, any amendment of or
         supplement to a Shelf Registration Statement or a Prospectus, of which
         the Stockholders or Holders and their counsel shall not have previously
         been advised and furnished a copy and of which the Stockholders or
         Holders or their counsel shall not have objected to within 10 Business
         Days of the date of receipt;

                  (k) make available for inspection by a representative of the
         Holders of the Registrable Securities (an "Inspector"), any underwriter
         participating in any disposition pursuant to such Shelf Registration
         Statement, and attorneys and accountants designated by the Holders, at
         reasonable times and in a reasonable manner, all pertinent financial
         and other records, documents and properties of the Company, and cause
         the respective officers, directors and employees of the Company to
         supply all information reasonably requested by any such Inspector,
         managing underwriter, attorney or accountant in connection with a Shelf
         Registration Statement; provided that if any such information is
         identified by the Company as being confidential or proprietary, each
         Person receiving such information shall take such actions as are
         reasonably necessary to protect the confidentiality of such information
         to the extent such action is otherwise not inconsistent with, an
         impairment of or in derogation of the rights and interests of any
         Inspector, Holder or underwriter);

                  (l) if reasonably requested by any Holder of Registrable
         Securities covered by a Shelf Registration Statement, promptly include
         in a Prospectus supplement or post-effective amendment such information
         with respect to such Holder to facilitate sales of Registrable
         Securities by such Holder and make all required filings of such
         Prospectus supplement or such post-effective amendment as soon as the
         Company has received notification of the matters to be incorporated in
         such filing; and

                  (m) use its reasonable best efforts to enter into such
         customary agreements and take all such other actions as are reasonably
         requested in connection therewith (including those requested by the
         Majority Holders of the Registrable Securities being sold) in order to
         expedite or facilitate the disposition of such Registrable Securities
         including, but not limited to, an Underwritten Offering, and in such
         connection, (i) to the extent possible, make such representations and
         warranties to the Holders and any underwriters of such Registrable
         Securities with respect to the business of the Company and the
         Company's subsidiaries, the Shelf Registration Statement, Prospectus
         and documents incorporated by

                                       5
<PAGE>

         reference or deemed incorporated by reference, if any, in each case, in
         form, substance and scope as are customarily made by issuers to
         underwriters in underwritten offerings and confirm the same if and when
         requested, (ii) obtain opinions of counsel to the Company (which
         opinions, in form, scope and substance, shall be reasonably
         satisfactory to the Majority Holders and the managing underwriters and
         their respective counsel) addressed to each selling Holder and
         underwriter of Registrable Securities, covering the matters customarily
         covered in opinions requested in underwritten offerings, (iii) obtain
         "comfort" letters from the independent certified public accountants of
         the Company (and, if necessary, any other certified public accountant
         of any subsidiary of the Company, or of any business acquired by the
         Company for which financial statements and financial data are or are
         required to be included in the Shelf Registration Statement) addressed
         to each selling Holder and underwriter of Registrable Securities, such
         letters to be in customary form and covering matters of the type
         customarily covered in "comfort" letters in connection with
         underwritten offerings and (iv) deliver such documents and certificates
         as may be reasonably requested by the Majority Holders of the
         Registrable Securities being sold or the underwriters, and which are
         customarily delivered in underwritten offerings, to evidence the
         continued validity of the representations and warranties of the Company
         made pursuant to clause (i) above and to evidence compliance with any
         customary conditions contained in an underwriting agreement.

         The Company may require each Holder of Registrable Securities to
furnish to the Company such information regarding such Holder and the proposed
disposition by such Holder of such Registrable Securities as the Company may
from time to time reasonably request in writing. The Company may exclude from
any Shelf Registration Statement the Registrable Securities of any Holder who
unreasonably fails to furnish such information within a reasonable time after
receiving such request (but not other Holders).

         Each Holder of Registrable Securities agrees that, upon receipt of any
notice from the Company of the happening of any event of the kind described in
Section 3(e)(ii)(A), 3(e)(iii), 3(e)(iv)(B) or 3(e)(v) hereof, such Holder will
forthwith discontinue disposition of Registrable Securities pursuant to a Shelf
Registration Statement until such Holder's receipt of the copies of the
supplemented or amended Prospectus contemplated by Section 3(i) hereof or until
it is advised in writing (the "Advice") by the Company that the use of the
applicable Prospectus may be resumed, and, if so directed by the Company, such
Holder will deliver to the Company all copies in its possession, other than
permanent file copies then in such Holder's possession, of the Prospectus
covering such Registrable Securities that is current at the time of receipt of
such notice.

         Subject to Section 3(m), the Holders of at least $10 million in
aggregate principal amount of Registrable Securities covered by a Shelf
Registration Statement who desire to do so may sell such Registrable Securities
in an Underwritten Offering. In any such Underwritten Offering, underwriters
that will administer the offering will be selected by the Majority Holders of
the Registrable Securities included in such offering and shall be approved by
the Company, which approval shall not be unreasonably withheld. No Holder of
Registrable Securities may participate in any Underwritten Offering unless such
Holder (i) agrees to sell such Holder's Registrable Shares on the basis provided
in any underwriting arrangements approved by the Persons entitled hereunder to
approve such arrangements, and (ii) completes and executes all questionnaires,
powers of attorney, indemnities, underwriting agreements and other documents
required in connection with such Underwritten Offering.

         4. Indemnification and Contribution. (a) The Company agrees to
indemnify and hold harmless each Holder and its affiliates (and their officers
and directors (or analogous principals)), and each Person, if any, who controls
such Holder within the meaning of Section 15 of the Securities Act or Section 20
of the Exchange Act, from and against any and all losses, claims, damages and
liabilities (including, without limitation, reasonable legal fees and other
expenses incurred in connection with any suit, action or proceeding or any claim
asserted), arising out of any untrue statement or alleged untrue statement of a
material fact contained in the Shelf Registration Statement or any Prospectus,
or arising out of any omission or alleged omission to state therein a

                                       6
<PAGE>

material fact required to be stated therein or necessary in order to make the
statements therein, in the light of the circumstances under which they were
made, not misleading, except insofar as such losses, claims, damages or
liabilities (i) arise out of any untrue statement or omission or alleged untrue
statement or omission made in reliance upon and in conformity with any
information relating to such Holder furnished to the Company in writing by such
Holder expressly for use therein or (ii) would not have arisen if such Holder
had not failed to deliver a Prospectus, or amended or supplemental Prospectus.

         (b) Each Holder agrees, severally and not jointly, to indemnify and
hold harmless the Company and the other selling Holders, their respective
affiliates, the officers and directors of the Company and each Person, if any,
who controls the Company or any other selling Holder within the meaning of
Section 15 of the Securities Act or Section 20 of the Exchange Act to the same
extent as the indemnity set forth in paragraph (a) above, but only with respect
to any losses, claims, damages or liabilities arising out of any untrue
statement or omission or alleged untrue statement or omission made in reliance
upon and in conformity with any information relating to such Holder furnished to
the Company in writing by such Holder expressly for use in the Shelf
Registration Statement and any Prospectus.

         (c) If any suit, action, proceeding (including any governmental or
regulatory investigation), claim or demand shall be brought or asserted against
any Person in respect of which indemnification may be sought pursuant to either
paragraph (a) or (b) above, such Person (the "Indemnified Person") shall
promptly notify the Person against whom such indemnification may be sought (the
"Indemnifying Person") in writing; provided that the failure to notify the
Indemnifying Person shall not relieve it from any liability that it may have
under this Section 4 except to the extent that it has been materially prejudiced
(through the forfeiture of substantive rights or defenses) by such failure; and
provided, further, that the failure to notify the Indemnifying Person shall not
relieve it from any liability that it may have to an Indemnified Person
otherwise than under this Section 4. If any such proceeding shall be brought or
asserted against an Indemnified Person and it shall have notified the
Indemnifying Person thereof, (i) in case the Indemnified Persons are Holders,
their officers or directors and any control Persons, counsel to the Indemnified
Persons shall be selected by the Majority Holders and (ii) in the case the
Indemnified Persons are the Company, their officers and directors and any
control Persons, counsel to the Indemnified Persons shall be selected by the
Company. In any such proceeding, any Indemnifying Person shall have the right to
participate in the defense by retaining its own counsel, but the fees and
expenses of such counsel shall be at the expense of such Indemnifying Person. It
is understood and agreed that the Indemnifying Person shall not, in connection
with any proceeding or related proceeding in the same jurisdiction, be liable
for the fees and expenses of more than one separate firm (in addition to any
local counsel) separate from their own counsel for all Indemnified Persons, and
that all such fees and expenses shall be reimbursed as they are incurred. The
Indemnifying Person shall not be liable for any settlement of any proceeding
effected without its written consent, but if settled with such consent or if
there be a final judgment for the plaintiff, the Indemnifying Person agrees to
indemnify each Indemnified Person from and against any loss or liability by
reason of such settlement or judgment. No Indemnifying Person shall, without the
written consent of the Indemnified Person, effect any settlement of any pending
or threatened proceeding in respect of which any Indemnified Person is or could
have been a party and indemnification could have been sought hereunder by such
Indemnified Person, unless such settlement (A) includes an unconditional release
of such Indemnified Person in form and substance reasonably satisfactory to such
Indemnified Person from all liability on claims that are the subject matter of
such proceeding and (B) does not include any statement as to or any admission of
fault, culpability or a failure to act by or on behalf of any Indemnified
Person.

         (d) If the indemnification provided for in paragraph (a) above is
unavailable to an Indemnified Person or insufficient in respect of any losses,
claims, damages or liabilities referred to therein, then each Indemnifying
Person under such paragraph, in lieu of indemnifying such Indemnified Person
thereunder, shall contribute to the amount paid or payable by such Indemnified
Person as a result of such losses, claims, damages or liabilities in such
proportion as is appropriate to reflect the relative fault of the Company on the
one hand and

                                       7
<PAGE>

the Holders on the other in connection with the statements or omissions that
resulted in such losses, claims, damages or liabilities, as well as any other
relevant equitable considerations. The relative fault of the Company on the one
hand and the Holders on the other shall be determined by reference to, among
other things, whether the untrue or alleged untrue statement of a material fact
or the omission or alleged omission to state a material fact relates to
information supplied by the Company or by the Holders and the parties' relative
intent, knowledge, access to information and opportunity to correct or prevent
such statement or omission.

         If the indemnification provided for in paragraph (b) above is
unavailable to an Indemnified Person or insufficient in respect of any losses,
claims, damages or liabilities referred to therein, then each Indemnifying
Person under such paragraph, in lieu of indemnifying such Indemnified Person
thereunder, shall contribute to the amount paid or payable by such Indemnified
Person as a result of such losses, claims, damages or liabilities in such
proportion as is appropriate to reflect the relative benefits received by the
Indemnifying Person from the offering of the Securities.

         (e) The Company and the Holders agree that it would not be just and
equitable if contribution pursuant to this Section 4 were determined by pro rata
allocation (even if the Holders were treated as one entity for such purpose) or
by any other method of allocation that does not take account of the equitable
considerations referred to in paragraph (d) above. The amount paid or payable by
an Indemnified Person as a result of the losses, claims, damages and liabilities
referred to in paragraph (d) above shall be deemed to include, subject to the
limitations set forth above, any reasonable legal or other expenses incurred by
such Indemnified Person in connection with any such action or claim.
Notwithstanding the provisions of this Section 4, in no event shall a Holder be
required to contribute any amount in excess of the amount by which the total
price at which the Securities sold by such Holder exceeds the amount of any
damages that such Holder has otherwise been required to pay by reason of such
untrue or alleged untrue statement or omission or alleged omission. No Person
guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of
the Securities Act) shall be entitled to contribution from any Person who was
not guilty of such fraudulent misrepresentation. The Holders' respective
obligations to contribute pursuant to Sections 4(d) and 4(e) are several in
proportion to the respective number of Registrable Securities of such Holder
that were registered pursuant to a Shelf Registration Statement.

         (f) The remedies provided for in this Section 4 are not exclusive and
shall not limit any rights or remedies that may otherwise be available to any
Indemnified Person at law or in equity.

         (g) The indemnity and contribution provisions contained in this Section
4 shall remain operative and in full force and effect regardless of (i) any
termination of this Agreement, (ii) any investigation made by or on behalf of
the Stockholders or any Holder or any Person controlling any Stockholder or any
Holder, or by or on behalf of the Company or the officers or directors of or any
Person controlling the Company, (iii) acceptance of any of the Securities and
(iv) any sale of Registrable Securities pursuant to a Shelf Registration
Statement.

         5. General.

         (a) No Inconsistent Agreements. The Company represents, warrants and
agrees that (i) the rights granted to the Holders hereunder do not in any way
conflict with and are not inconsistent with the rights granted to the holders of
any other outstanding securities issued or guaranteed by the Company under any
other agreement and (ii) the Company has not entered into, or on or after the
date of this Agreement will not enter into, any agreement that is inconsistent
with the rights granted to the Holders of Registrable Securities in this
Agreement or otherwise conflicts with the provisions hereof.

         (b) Amendments and Waivers. The provisions of this Agreement, including
the provisions of this sentence, may not be amended, modified or supplemented,
and waivers or consents to departures from the provisions of this Agreement may
not be given without the written consent of the Company and of at least the

                                       8
<PAGE>

Majority Holders of the outstanding Registrable Securities affected by such
amendment, modification, supplement, waiver or consent; provided that no
amendment, modification, supplement, waiver or consent to any departure from the
provisions of Section 5 hereof shall be effective as against any Holder of
Registrable Securities unless consented to in writing by such Holder.

         (c) Notices. All notices and other communications provided for or
permitted hereunder shall be made in writing by hand-delivery, registered
first-class mail, telex, telecopier, or any courier guaranteeing overnight
delivery (i) if to a Holder, at the most current address given by such Holder to
the Company by means of a notice given in accordance with the provisions of this
Section 5(c), which address initially is, with respect to the Stockholders, the
address set forth in this Agreement; (ii) if to the Company, initially at the
Company's address set forth in this Agreement and thereafter at such other
address, notice of which is given in accordance with the provisions of this
Section 5(c); and (iii) to such other persons at their respective addresses as
provided in this Agreement and thereafter at such other address, notice of which
is given in accordance with the provisions of this Section 5(c). All such
notices and communications shall be deemed to have been duly given: at the time
delivered by hand, if personally delivered; five Business Days after being
deposited in the mail, postage prepaid, if mailed; when answered back, if
telexed; when receipt is acknowledged, if telecopied; and on the next Business
Day if timely delivered to an air courier guaranteeing overnight delivery.

         (d) Successors and Assigns. This Agreement shall inure to the benefit
of and be binding upon the successors, assigns and transferees of each of the
parties, including, without limitation and without the need for an express
assignment, subsequent Holders. If any transferee of any Holder shall acquire
Registrable Securities in any manner, whether by operation of law or otherwise,
such Registrable Securities shall be held subject to all the terms of this
Agreement, and by taking and holding such Registrable Securities such Person
shall be conclusively deemed to have agreed to be bound by and to perform all of
the terms and provisions of this Agreement and such Person shall be entitled to
receive the benefits hereof.

         (e) Third Party Beneficiaries. Each Holder shall be a third party
beneficiary to the agreements made hereunder between the Company, on the one
hand, and the Stockholders, on the other hand, and shall have the right to
enforce such agreements directly to the extent it deems such enforcement
necessary or advisable to protect its rights or the rights of other Holders
hereunder.

         (f) Counterparts. This Agreement may be executed in any number of
counterparts and by the parties hereto in separate counterparts, each of which
when so executed shall be deemed to be an original and all of which taken
together shall constitute one and the same agreement.

         (g) Headings. The headings in this Agreement are for convenience of
reference only, are not a part of this Agreement and shall not limit or
otherwise affect the meaning hereof.

         (h) Governing Law. This Agreement shall be governed by and construed in
accordance with the internal laws of the State of Texas (without regard to rules
or principles of conflicts of law requiring the application of the law of
another State) and all applicable federal laws.

         (i) Miscellaneous. This Agreement contains the entire agreement between
the parties relating to the subject matter hereof and supersedes all oral
statements and prior writings with respect thereto. If any term, provision,
covenant or restriction contained in this Agreement is held by a court of
competent jurisdiction to be invalid, void or unenforceable or against public
policy, the remainder of the terms, provisions, covenants and restrictions
contained herein shall remain in full force and effect and shall in no way be
affected, impaired or invalidated. The Company and the Holders shall endeavor in
good faith negotiations to replace the invalid, void or unenforceable provisions
with valid provisions the economic effect of which comes as close as possible to
that of the invalid, void or unenforceable provisions.

                                       9
<PAGE>

                            [SIGNATURE PAGE FOLLOWS]

                                       10
<PAGE>

         IN WITNESS WHEREOF, the parties have executed this Agreement as of the
date first written above.

                                      NUEVO ENERGY COMPANY

                                      By:
                                             ---------------------------------

                                              By:
                                                 -----------------------------
                                              Name:
                                                   ---------------------------
                                              Title:
                                                    --------------------------

Confirmed and accepted as of the
date first above written:

Yorktown Energy Partners III, L.P.,
By its General Partner,
Yorktown III Company LLC

By:
   -----------------------------
Name:
     ---------------------------
Title:
      --------------------------

Yorktown Energy Partners IV, L.P.
By its General Partner,
Yorktown IV Company LLC

By:
   -----------------------------
Name:
     ---------------------------
Title:
      --------------------------

Yorktown Partners LLC

By:
   -----------------------------
Name:
     ---------------------------
Title:
      --------------------------

SAFIC S.A.

By:
   -----------------------------
Name:
     ---------------------------
Title:
      --------------------------

--------------------------------
Charles de Mestral

                                       11
<PAGE>

--------------------------------
J. Ross Craft

Montana Oil and Gas, Ltd.,
By its General Partner,
Glendive Management, LLC

By:
   -----------------------------
Name:
     ---------------------------
Title:
      --------------------------

--------------------------------
David A. Badley

--------------------------------
James S. Scott

--------------------------------
Glenn Reed

--------------------------------
Doug Allison

--------------------------------
Mohamed Yaich

                                       12

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