Document:

<PAGE>

                                                                    Exhibit 10.6

        SECOND AMENDMENT TO FOURTH AMENDED AND RESTATED CREDIT AGREEMENT

     This SECOND AMENDMENT TO FOURTH AMENDED AND RESTATED CREDIT AGREEMENT (this
"Second Amendment") is entered into this 27th day of June, 2003, to be effective
for all purposes as of June 27, 2003 (the "Amendment Effective Date"), by and
among QUICKSILVER RESOURCES INC., a Delaware corporation (the "Borrower"), the
Subsidiary Guarantors defined herein, the undersigned Banks, and BANK OF
AMERICA, N.A. as administrative agent (the "Administrative Agent") for the Banks
and as a Bank. Capitalized terms which are used herein without definition and
which are defined in the Agreement referred to below shall have the meanings
ascribed to them in the Agreement.

     WHEREAS, the Borrower, the Administrative Agent and the Banks are parties
to that certain Fourth Amended and Restated Credit Agreement dated as of May 13,
2002, as amended by that certain First Amendment dated as of September 25, 2002
(the "Agreement"); and

     WHEREAS, the Borrower desires to issue the Subordinate Notes and to use
part of the proceeds thereof to repay the 14.75% Subordinate Notes, and the
Borrower, the Administrative Agent and the undersigned Banks desire to modify
certain terms of the Agreement, subject to the terms hereof;

     NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, the parties hereto hereby agree as
follows:

     SECTION 1. Amendments to the Agreement. In reliance on the representations,
warranties, covenants and agreements contained in this Second Amendment, and
subject to satisfaction of the conditions precedent set forth in Section 3 of
this Second Amendment, the Agreement is hereby amended as follows:

     (a) Amendments to Section 2.1 (Definitions). (i) The definitions of "Change
of Control," "Obligations," "Permitted Redemption," "Restricted Payment,"
"Subordinate Debt," "Subordinate Note Agreement," "Subordinate Notes,"
"Subordination Agreement" and "TCW Agent" are amended in their entirety to read
as set forth below, and the definitions of "14.75% Subordinate Notes," "14.75%
Subordinate Noteholders," "53 Million Subordinate Debt," "$53 Million
Subordinate Note Agreement," and "Subordinate Note Collateral Agent" are added
in the form set forth below:

               "14.75% Subordinate Notes" means, collectively, each of
          Borrower's 14.75% Second Mortgage Notes due March 30, 2009.

               "14.75% Subordinate Noteholders" means each holder of 14.75%
          Subordinate Notes and their successors and assigns.

               "$53 Million Subordinate Debt" means all Debt of Borrower
          outstanding under the $53 Million Subordinate Note Agreement.

<PAGE>

               "$53 Million Subordinate Note Agreement" means that certain Note
          Purchase Agreement dated as of March 31, 2000 by and among the
          Borrower, TCW Agent and 14.75% Subordinate Noteholders.

               "Change of Control" means (a) the acquisition of ownership,
          directly or indirectly, beneficially or of record, by any Person or
          group (within the meaning of the Securities Exchange Act of 1934 and
          the rules of the SEC thereunder as in effect on the date hereof) other
          than the Darden Group, of Equity Interests representing more than 30%
          of the aggregate ordinary voting power represented by the issued and
          outstanding Equity Interests of the Company or (b) occupation of a
          majority of the seats (other than vacant seats) on the board of
          directors of the Company by Persons who were neither (i) nominated by
          the board of directors of the Company nor (ii) appointed by directors
          a majority of whom was so nominated.

               "Obligations" means all present and future indebtedness,
          obligations and liabilities, and all renewals and extensions thereof,
          or any part thereof, of each Credit Party to Administrative Agent or
          to any Bank or any Affiliate of any Bank arising pursuant to the Loan
          Papers or pursuant to any Hedge Agreement or Hedge Transaction with
          any Bank or any Affiliate of any Bank while such Person or its
          Affiliate is a party to this Agreement, and all interest accrued
          thereon and costs, expenses, and attorneys' fees incurred in the
          enforcement or collection thereof, regardless of whether such
          indebtedness, obligations and liabilities are direct, indirect, fixed,
          contingent, liquidated, unliquidated, joint, several or joint and
          several.

               "Permitted Redemption" means (a) the retirement, redemption or
          payment at any time and from time to time by Borrower or any Affiliate
          of Borrower of all or a portion of the principal of and interest on
          the Mercury Subordinate Debt prior to the stated maturity thereof, or
          (b) delivery of gas volumes at any time and from time to time prior to
          the stated delivery date thereof by Borrower or any Affiliate of
          Borrower under the Falcon Seaboard Settlement Agreement.

               "Restricted Payment" means, with respect to any Person, (a) any
          Distribution by such Person, or (b) the retirement, purchase,
          repurchase, redemption, defeasance or prepayment prior to scheduled
          maturity by such Person or any Affiliate of such Person of any Debt
          (other than the Subordinate Debt) of such Person, other than Permitted
          Redemptions.

               "Subordinate Debt" means all Debt of Borrower and the Subsidiary
          Guarantors outstanding under the Subordinate Note Agreement, including
          all renewals and extensions thereof to the extent permitted hereunder.

                                       -2-

<PAGE>

               "Subordinate Note Agreement" means that certain $70,000,000 Note
          Purchase Agreement dated June 27, 2003 by and among the Borrower,
          Subordinate Note Collateral Agent and Subordinate Noteholders, as the
          same may be modified, amended, renewed, extended or restated from time
          to time to the extent permitted hereunder and under the Subordination
          Agreement.

               "Subordinate Note Collateral Agent" means BNP Paribas as
          Collateral Agent for the Subordinate Noteholders under the Subordinate
          Note Agreement.

               "Subordinate Notes" means, collectively, each of Borrower's
          Senior Subordinated Second Lien Mortgage Notes due December 31, 2006.

               "Subordination Agreement" means the terms and provisions of the
          Subordinate Note Agreement with respect to subordination of the
          Subordinate Debt, including without limitation Article XVI of the
          Subordinate Note Agreement, as the same may be renewed, extended,
          amended and restated from time to time to the extent permitted
          hereunder.

               "TCW Agent" means TCW Asset Management Company, a California
          corporation, as collateral agent for the 14.75% Subordinate
          Noteholders under the $53 Million Subordinate Note Agreement."

     (ii) Clause (i) of the definition of "Permitted Encumbrances" is amended in
its entirety to read as follows: "(i) Liens in favor of the Subordinate
Noteholders or their collateral agent to secure the Subordinate Debt which are
junior, subordinate and inferior to the Liens of the Mortgages;".

     (b) Amendment to Section 9.23(a) (Subordinate Debt). Subsection (a) of
Section 9.23 of the Agreement is amended by (i) substituting "$70,000,000" for
"$53,000,000" wherever the latter appears, and (ii) deleting the parenthetical
clause "(except as otherwise permitted in the Subordinate Note Agreement in
connection with the issuance of new notes in lieu of the payment of cash
interest thereunder)."

     (c) Amendment to Section 11.2 (Restricted Payments). Clause (ii) of
subsection (d) of the second proviso in Section 11.2 of the Agreement is deleted
in its entirety, and clause (iii) is renumbered as clause (ii); and renumbered
clause (ii) is amended in its entirety to read as follows: "(ii) repurchase,
during the term of this Agreement, a portion of its common stock, par value $.01
per share, for an aggregate and cumulative purchase price of not more than
$5,000,000 (as such $5,000,000 may be reduced by any prepayments or redemptions
of Subordinate Debt to the extent permitted by Section 11.14 hereof)."

     (d) Amendment to Section 11.6 (Amendment to Organizational Documents; Other
Material Agreements). Section 11.6 of the Agreement is amended in its entirety
to read as

                                       -3-

<PAGE>

follows: "Borrower will not, nor will Borrower permit any other Credit Party to,
enter into or permit any modification or amendment of, or waive any material
right or obligations of any Person under, (a) its certificate or articles of
incorporation, bylaws, partnership agreement, regulations or other
organizational documents other than amendments, modifications and waivers which
could not, individually or in the aggregate, result in a Material Adverse
Change, (b) the Subordinate Note Documents, (c) the Section 29 Documents, (d)
the Mercury Subordinate Note, and (e) the Commodity Price Risk Policy; provided,
that if Borrower exercises one or more of its options to repurchase Mineral
Interests pursuant to rights of repurchase granted to Borrower or its
predecessor pursuant to the Section 29 Documents, Borrower may amend, terminate,
cancel or release any and all of the Section 29 Documents other than the
Mortgages in favor of the Administrative Agent (which Mortgages shall remain in
effect) as reasonably necessary to consummate any such repurchases in accordance
with the Section 29 Documents; provided further, that Borrower may enter into
amendments to the Subordinate Note Documents which do not provide for or have
any of the following effects: (i) increase the aggregate principal amount of the
Subordinate Debt beyond the $70,000,000 presently outstanding (as reduced by any
prepayments or redemptions to the extent permitted by Section 11.14 hereof or
any other principal payments hereafter made with the express written consent of
the Required Banks); (ii) increase the amount of any scheduled payment of
principal or interest on the Subordinate Debt; (iii) hasten or accelerate the
date upon which any installment of principal or interest of any Subordinate Debt
is due or otherwise accelerate the amortization schedule with respect to such
Subordinate Debt; (iv) increase the rate of interest payable in cash accruing on
the Subordinate Debt (other than any increase to the `Default Rate' in the
circumstances already provided for in the Subordinate Note Agreement), or impose
any additional premium or penalty in connection with the prepayment or late
payment of the Subordinate Debt; (v) provide for the payment of additional fees
or for any increase in existing fees in connection with any Subordinate Debt;
(vi) add any covenant or obligation of Borrower to any Subordinate Noteholder
which is not contained in this Agreement as then in effect; or (vii) amend or
modify any covenant, obligation or default of Borrower to any Subordinate
Noteholder (including, without limitation, financial ratios) in a manner which
makes such covenants, obligations or defaults more restrictive or onerous than
those contained in the Subordinate Note Agreement as in effect on June 27, 2003
or in this Agreement as then in effect. The Subordinate Noteholders shall be
entitled to receive fees for amendments (to the extent such amendments are
permitted hereby), providing consents, waiving defaults or granting forbearances
(but solely to the extent such fees are customary, do not exceed market rates
and are permitted by the Subordination Agreement), and to the reimbursement of
any reasonable out-of-pocket expenses (including fees of attorneys, appraisers,
consultants and advisors) relating thereto in accordance with the terms of the
Subordinate Notes."

     (e) Amendment to Section 11.7 (Use of Proceeds). Section 11.7 is amended by
amending clause (d) thereof in its entirety to read as follows: "(d) to finance
the Permitted Redemptions and prepayments or redemptions of Subordinate Debt, in
each instance to the extent permitted by Section 11.14 hereof."

     (f) Amendment to Section 11.14 (Subordinate Debt, Mercury Subordinate Debt,
and Falcon Seaboard Settlement Agreement). Section 11.14 is amended in its
entirety to read as follows: "In addition to the other restrictions contained in
this Article XI, Borrower will not, nor

                                       -4-

<PAGE>

will Borrower permit any other Credit Party to, directly or indirectly, (a) make
any payment of principal of the Subordinate Debt or any other item of the
Subordinate Debt (other than accrued interest thereon) or payment in respect of
the purchase, repurchase, redemption or defeasance of principal or such other
item of the Subordinate Debt (other than accrued interest thereon) at any time
prior to the earlier of (i) the termination of all Commitments and the payment
and performance in full of the Obligations or (ii) the scheduled maturity of the
Subordinate Debt, or any prepayment of interest of the Subordinate Debt or
payment in respect of any purchase, repurchase, redemption or defeasance of
interest of the Subordinate Debt prior to the time that such interest is due,
except as expressly permitted by the terms hereof and by the terms of the
Subordination Agreement, or permit the outstanding principal balance of the
Subordinate Notes to exceed $70,000,000; (b) make any payment on or with respect
to any Mercury Subordinate Debt, except as expressly permitted by the terms of
this Agreement and by the terms of the Mercury Subordinate Note, or permit the
outstanding principal balance of the Mercury Subordinate Note to exceed
$4,000,000; or (c) make any delivery on or with respect to the Falcon Seaboard
Settlement Agreement, except as expressly permitted by the terms of the Falcon
Seaboard Settlement Agreement; provided, however, that Borrower may (x) make
Permitted Redemptions of the Mercury Subordinate Debt and under the Falcon
Seaboard Settlement Agreement, and (y) prepay, retire or redeem at any time and
from time to time all or a portion of the principal of, interest on and
Make-Whole Amount (as defined in the Subordinate Note Agreement) of the
Subordinate Debt prior to the scheduled maturity thereof, in each instance so
long as, and only so long as, both immediately before and after giving effect
thereto, (i) no Default, Event of Default, or Borrowing Base Deficiency has
occurred and is continuing or results therefrom, and (ii) at least $10,000,000
of Availability exists at the time thereof; provided further, that Borrower may
prepay, retire or redeem at any time and from time to time all or a portion of
the principal of, interest on and Make-Whole Amount of the Subordinate Debt
prior to the scheduled maturity thereof so long as, and only so long as, both
immediately before and after giving effect thereto, (i) no Default, Event of
Default, or Borrowing Base Deficiency has occurred and is continuing or results
therefrom, and (ii) the aggregate and cumulative amount of all such prepayments
or redemptions of Subordinate Debt, together with the aggregate and cumulative
amount of all repurchases of the Company's common stock, par value $.01 per
share (to the extent such repurchases of common stock are permitted by this
Agreement), does not exceed $5,000,000. Administrative Agent and the Banks agree
to enter into any amendment, waiver or other document, letter or agreement under
the Subordinate Note Documents in order to permit the prepayment, retirement or
redemption thereunder, subject to the restrictions set forth in this Section
11.14."

     (g) Amendment to Section 13.1 (Events of Default). Paragraph (o) of Section
13.1 is amended by substituting "Subordinate Note Collateral Agent" for "TCW
Agent" wherever the latter appears.

     SECTION 2. Representations and Warranties. To induce the Administrative
Agent and the Banks to enter into this Second Amendment, the Borrower represents
and warrants to the Administrative Agent and to each Bank that:

     (a) The execution, delivery and performance by Borrower of this Second
Amendment are within Borrower's corporate powers and have been duly authorized
by all necessary

                                       -5-

<PAGE>

corporate action. This Second Amendment has been duly executed and delivered by
the Borrower and constitutes the legal, valid and binding obligation of the
Borrower enforceable in accordance with its respective terms, except as (i) the
enforceability thereof may be limited by bankruptcy, insolvency or similar Laws
affecting creditors' rights generally, and (ii) the availability of equitable
remedies may be limited by equitable principles of general application.

     (b) The representations and warranties set forth in Article IX of the
Agreement are true and correct on and as of the date of execution hereof and as
of the Amendment Effective Date, and will be true and correct after giving
effect to this Second Amendment, as if made on and as of the date of execution
hereof and as of the Amendment Effective Date.

     (c) As of the date of execution hereof and as of the Amendment Effective
Date, at the time of and after giving effect to this Second Amendment, no
Default or Event of Default has occurred and is continuing.

     (d) No approval, consent, exemption, authorization or other action by, or
notice to, or filing (other than routine informational filings with the SEC)
with, any Governmental Authority is necessary or required in connection with the
execution and delivery of this Second Amendment or the performance by the
Borrower of its obligations hereunder. The execution, delivery and performance
of this Second Amendment and the other documents and transactions contemplated
hereby does not and will not (i) contravene the terms of the Borrower's
organization documents; (ii) conflict with or result in any breach or
contravention of, or result in or require the imposition or creation of any Lien
under, any document evidencing any material Contractual Obligation to which the
Borrower is a party or any order, injunction, writ or decree of any Governmental
Authority to which the Borrower is subject; or (iii) violate any Laws.

     (e) Borrower has no defenses to payment, counterclaim or rights of set-off
with respect to the Obligations existing on the date hereof.

     SECTION 3. Conditions of Effectiveness. The amendments to the Agreement set
forth in Section 2 of this Second Amendment shall be effective as of the
Amendment Effective Date upon satisfaction of the following conditions
precedent:

          (a) Amendment. The Administrative Agent shall have received
     counterparts of (i) this Second Amendment duly executed by the Borrower,
     each Subsidiary Guarantor, and the Required Banks and (ii) the Subordinate
     Note Agreement duly executed by the Borrower, the Subordinate Note
     Collateral Agent, and the Subordinate Noteholders. The terms and provisions
     of the Subordinate Note Agreement shall be satisfactory to the
     Administrative Agent and the Required Banks in their sole discretion.

          (b) Payment of Fees and Expenses. The Borrower shall have paid all
     accrued, unpaid fees, costs and expenses owed pursuant to this Second
     Amendment, the Agreement or any other agreement between the Borrower and
     the Administrative Agent or any Bank pertaining thereto, to the extent then
     due and payable, together with reasonable fees and expenses of counsel for
     the Administrative Agent to the extent then invoiced prior to or on the
     closing date of this Second Amendment.

                                       -6-

<PAGE>

          (c) Certificate (Closing of Subordinate Debt). The Administrative
     Agent shall have received a certificate signed by an Authorized Officer of
     Borrower certifying that (i) the Borrower is consummating the Subordinate
     Debt closing in accordance with the terms of the Subordinate Note
     Documents, with all material conditions precedent thereto having been
     satisfied in all material respects by the parties thereto, (ii) the $53
     Million Subordinate Debt is being paid in full with a portion of the
     proceeds of the Subordinate Notes, and (iii) all Liens securing the $53
     Million Subordinate Debt have been released.

          (d) Copy of New Subordinate Note Documents. The Administrative Agent
     shall have received a certificate of an Authorized Officer of Borrower,
     identifying the Subordinate Note Documents; true and correct copies of the
     Subordinate Note Documents shall be attached to such certificate or shall
     have been previously delivered to the Administrative Agent. The terms and
     provisions of the Subordinate Note Documents shall be satisfactory to the
     Administrative Agent in its sole discretion.

          (e) No Material Adverse Change. The Administrative Agent shall have
     received a certificate signed by an Authorized Officer of Borrower
     certifying that no event or circumstance has occurred that has resulted or
     would reasonably be expected to result in a Material Adverse Change.

          (f) No Default. The Administrative Agent shall have received a
     certificate signed by an Authorized Officer of Borrower certifying that as
     of the Amendment Effective Date, no Default or Event of Default has
     occurred and is continuing.

          (g) Legal Opinions. The Administrative Agent shall have received an
     opinion of Cantey & Hanger, L.L.P., counsel to the Borrower, in form and
     substance satisfactory to the Administrative Agent and its counsel.

          (h) Other. The Administrative Agent shall have received such other
     approvals, opinions and documents as the Administrative Agent deems
     appropriate.

Upon satisfaction of the foregoing conditions precedent set forth in this
Section 3, the Administrative Agent shall notify the Borrower and the Banks in
writing.

     SECTION 4. Costs, Expenses. The Borrower agrees to pay on demand all
reasonable fees and expenses of counsel for the Administrative Agent and all
other costs and expenses of the Administrative Agent incurred in connection with
the preparation, negotiation, execution and delivery of this Second Amendment
and related documents and instruments.

     SECTION 5. Effect of Amendment. This Second Amendment (i) except as
provided herein, shall not be deemed to be a consent to the modification or
waiver of any other term or condition of the Agreement or of any of the
instruments or agreements referred to therein and (ii) shall not prejudice any
right or rights which the Administrative Agent or the Banks may now have under
or in connection with the Agreement, as amended by this Second Amendment. Except
as otherwise provided by this Second Amendment, all of the terms, conditions and

                                       -7-

<PAGE>

provisions of the Agreement, as amended shall remain the same. It is declared
and agreed by each of the parties hereto that the Agreement, as previously
amended and as amended hereby, shall continue in full force and effect, and that
this Second Amendment and such Agreement shall be read and construed as one
instrument. The Borrower hereby acknowledges and agrees that the Obligations are
the legal, valid and binding obligations of the Borrower without offset,
counterclaim or defense, remain in full force and effect, are unimpaired by this
Second Amendment and are hereby affirmed by the Borrower. Borrower and each of
the other Credit Parties hereby confirm and agree that all Liens and other
security now or hereafter held by the Administrative Agent for the benefit of
the Banks as security for payment of the Obligations are the legal, valid and
binding obligations of the Borrower and the Credit Parties, remain in full force
and effect, are unimpaired by this Second Amendment, and are hereby ratified and
confirmed as security for payment of the Obligations.

     SECTION 6. Ratification of Subsidiary Guarantees. Each Subsidiary of
Borrower (other than Voyager) (each a "Subsidiary Guarantor," and collectively,
the "Subsidiary Guarantors") hereby consents to the execution of this Second
Amendment and reaffirms its guaranty of all of the Obligations of the Borrower
pursuant to its respective Subsidiary Guaranty. Borrower and each Subsidiary
Guarantor confirms and agrees that (a) neither the execution of this Second
Amendment nor the consummation of the transactions described herein shall in any
way effect, impair or limit the covenants, liabilities, obligations and duties
of the Borrower or any Subsidiary Guarantor under the Loan Papers and (b) the
obligations evidenced and secured by the Loan Papers continue in full force and
effect. Each Subsidiary Guarantor hereby further confirms that it
unconditionally guarantees to the extent set forth in its respective Subsidiary
Guaranty the due and punctual payment and performance of any and all amounts and
obligations owed by the Borrower to the Banks under the Agreement and the other
Loan Papers.

     SECTION 7. Authorization to Administrative Agent. By execution of a
counterpart of this Second Amendment, each of the undersigned Banks does hereby
approve the form of the Subordinate Note Agreement previously delivered to the
Banks, with such changes thereto as may be approved by the Administrative Agent,
and authorizes the Administrative Agent to take such action with respect thereto
as the Administrative Agent deems appropriate.

     SECTION 8. Miscellaneous. THIS SECOND AMENDMENT AND THE OTHER LOAN PAPERS
HAVE BEEN EXECUTED AND DELIVERED IN THE STATE OF TEXAS AND SHALL BE CONSTRUED IN
ACCORDANCE WITH AND GOVERNED BY THE LAWS OF THE STATE OF TEXAS AND THE LAWS OF
THE UNITED STATES OF AMERICA, EXCEPT TO THE EXTENT THAT THE LAWS OF ANY STATE IN
WHICH ANY PROPERTY INTENDED AS SECURITY FOR THE OBLIGATIONS IS LOCATED
NECESSARILY GOVERN (A) THE PERFECTION AND PRIORITY OF THE LIENS IN FAVOR OF
ADMINISTRATIVE AGENT AND BANKS WITH RESPECT TO SUCH PROPERTY, AND (B) THE
EXERCISE OF ANY REMEDIES (INCLUDING FORECLOSURE) WITH RESPECT TO SUCH PROPERTY.
All of the terms and provisions of this Second Amendment shall bind and inure to
the benefit of the parties hereto and their respective successors and assigns.
No provision of this Second Amendment shall be interpreted or construed against
any Person solely because that Person or its legal representative drafted such
provision. The headings, captions and arrangements used in this Second Amendment
are, unless

                                       -8-

<PAGE>

specified otherwise, for convenience of reference only and shall not be deemed
to limit, amplify or modify the terms of this Second Amendment, nor affect the
meaning thereof. This Second Amendment may be executed in multiple counterparts,
and all parties need not execute the same counterpart; however, no party shall
be bound by this Second Amendment until Borrower and Required Banks have
executed and delivered a counterpart hereof. In proving this Second Amendment,
it shall not be necessary to produce or account for more than one such
counterpart. This Second Amendment may be delivered by facsimile transmission of
the relevant signature pages hereof.

                         [SIGNATURES BEGIN ON NEXT PAGE]

                                       -9-

<PAGE>

     THE  AGREEMENT  (AS  AMENDED BY THIS SECOND  AMENDMENT)  AND THE OTHER LOAN
PAPERS  REPRESENT  THE FINAL  AGREEMENT  AMONG THE PARTIES  WITH  RESPECT TO THE
SUBJECT  MATTER  HEREOF  AND MAY  NOT BE  CONTRADICTED  BY  EVIDENCE  OF  PRIOR,
CONTEMPORANEOUS OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES.

     THERE ARE NO UNWRITTEN ORAL AGREEMENTS BETWEEN OR AMONG THE PARTIES WITH
RESPECT TO THE SUBJECT MATTER HEREOF.

     IN WITNESS WHEREOF, the parties hereto have caused this Second Amendment to
be duly executed and delivered by their proper and duly authorized officers as
of the date and year first above written.

                                       QUICKSILVER RESOURCES INC.,
                                       a Delaware corporation

                                       By: /s/ Bill Lamkin
                                           -------------------------------------
                                           Name: Bill Lamkin
                                           Title: Executive Vice President and
                                                  Chief Financial Officer

    THIS IS A SIGNATURE PAGE TO THE QUICKSILVER RESOURCES SECOND AMENDMENT TO
                  FOURTH AMENDED AND RESTATED CREDIT AGREEMENT

<PAGE>

                                       SUBSIDIARY GUARANTORS:

                                       BEAVER CREEK PIPELINE, L.L.C.

                                       By: /s/ Bill Lamkin
                                           -------------------------------------
                                           Name: Bill Lamkin
                                           Title: Vice President and Treasurer

                                       CINNABAR ENERGY SERVICES & TRADING, LLC

                                       By: /s/ Bill Lamkin
                                           -------------------------------------
                                           Name: Bill Lamkin
                                           Title: Vice President and Treasurer

                                       TERRA ENERGY LTD.

                                       By: /s/ Bill Lamkin
                                           -------------------------------------
                                           Name: Bill Lamkin
                                           Title: Executive Vice President and
                                                  Chief Financial Officer

                                       MERCURY MICHIGAN INC.

                                       By: /s/ Bill Lamkin
                                           -------------------------------------
                                           Name: Bill Lamkin
                                           Title: Executive Vice President and
                                                  Chief Financial Officer

                                       GTG PIPELINE CORPORATION

                                       By: /s/ Bill Lamkin
                                           -------------------------------------
                                           Name: Bill Lamkin
                                           Title: Executive Vice President and
                                                  Chief Financial Officer

    THIS IS A SIGNATURE PAGE TO THE QUICKSILVER RESOURCES SECOND AMENDMENT TO
                  FOURTH AMENDED AND RESTATED CREDIT AGREEMENT

<PAGE>

                                       MGV ENERGY, INC.

                                       By: /s/ Brown Howard
                                           -------------------------------------
                                           Name: Brown Howard
                                           Title: VP Corporate Operation

                                       ENERGY ACQUISITION OPERATING CORPORATION

                                       By: /s/ Bill Lamkin
                                           -------------------------------------
                                           Name: Bill Lamkin
                                           Title: Executive Vice President and
                                                  Chief Financial Officer

                                       KRISTEN CORPORATION

                                       By: /s/ Bill Lamkin
                                           -------------------------------------
                                           Name: Bill Lamkin
                                           Title: Executive Vice President and
                                                  Chief Financial Officer

                                       TERRA PIPELINE COMPANY

                                       By: /s/  Bill Lamkin
                                           -------------------------------------
                                           Name: Bill Lamkin
                                           Title: Executive Vice President and
                                                  Chief Financial Officer

    THIS IS A SIGNATURE PAGE TO THE QUICKSILVER RESOURCES SECOND AMENDMENT TO
                  FOURTH AMENDED AND RESTATED CREDIT AGREEMENT

<PAGE>

                                       BANK OF AMERICA, N.A., as Administrative
                                       Agent and as a Bank

                                       By: /s/ Richard Stein
                                           -------------------------------------
                                           Richard Stein
                                           Principal

    THIS IS A SIGNATURE PAGE TO THE QUICKSILVER RESOURCES SECOND AMENDMENT TO
                  FOURTH AMENDED AND RESTATED CREDIT AGREEMENT

<PAGE>

                                       BNP PARIBAS, as a Bank

                                       By: /s/ Brian Malone
                                           -------------------------------------
                                           Name: Brian Malone
                                           Title: Managing Director

                                       By: /s/ Betsy Jocher
                                           -------------------------------------
                                           Name: Betsy Jocher
                                           Title: Vice President

    THIS IS A SIGNATURE PAGE TO THE QUICKSILVER RESOURCES SECOND AMENDMENT TO
                  FOURTH AMENDED AND RESTATED CREDIT AGREEMENT

<PAGE>

                                       CIBC INC., as a Bank

                                       By: /s/ Marybeth Ross
                                           -------------------------------------
                                           Name: Marybeth Ross
                                           Title: Authorized Signatory

    THIS IS A SIGNATURE PAGE TO THE QUICKSILVER RESOURCES SECOND AMENDMENT TO
                  FOURTH AMENDED AND RESTATED CREDIT AGREEMENT

<PAGE>

                                       CREDIT LYONNAIS, NEW YORK BRANCH, as a
                                       Bank

                                       By: /s/ Philippe Soustra
                                           -------------------------------------
                                           Name: Philippe Soustra
                                           Title: Executive Vice President

    THIS IS A SIGNATURE PAGE TO THE QUICKSILVER RESOURCES SECOND AMENDMENT TO
                  FOURTH AMENDED AND RESTATED CREDIT AGREEMENT

<PAGE>

                                       COMPASS BANK, as a Bank

                                       By: /s/ John M. Falbo
                                           -------------------------------------
                                           Name: John M. Falbo
                                           Title: Senior Vice President

    THIS IS A SIGNATURE PAGE TO THE QUICKSILVER RESOURCES SECOND AMENDMENT TO
                  FOURTH AMENDED AND RESTATED CREDIT AGREEMENT

<PAGE>

                                       FORTIS CAPITAL CORP., as a Bank

                                       By: /s/ Christopher S. Parada
                                           -------------------------------------
                                           Name: Christopher S. Parada
                                           Title: Vice President

                                       By: /s/ Darrell W. Holley
                                           -------------------------------------
                                           Name: Darrell W. Holley
                                           Title: Managing Director

    THIS IS A SIGNATURE PAGE TO THE QUICKSILVER RESOURCES SECOND AMENDMENT TO
                  FOURTH AMENDED AND RESTATED CREDIT AGREEMENT

<PAGE>

                                       THE BANK OF NOVA SCOTIA, as a Bank

                                       By: /s/ Nadine Bell
                                           -------------------------------------
                                           Name: Nadine Bell
                                           Title: Senior Manager

    THIS IS A SIGNATURE PAGE TO THE QUICKSILVER RESOURCES SECOND AMENDMENT TO
                  FOURTH AMENDED AND RESTATED CREDIT AGREEMENT

<PAGE>

                                       WASHINGTON MUTUAL BANK, as a Bank

                                       By: /s/ Russell R. Otts
                                           -------------------------------------
                                           Name: Russell R. Otts
                                           Title: Vice President

    THIS IS A SIGNATURE PAGE TO THE QUICKSILVER RESOURCES SECOND AMENDMENT TO
                  FOURTH AMENDED AND RESTATED CREDIT AGREEMENT

<PAGE>

                                       STERLING BANK, as a Bank

                                       By: /s/ C. Scott Wilson
                                           -------------------------------------
                                           Name: C. Scott Wilson
                                           Title: Vice President

    THIS IS A SIGNATURE PAGE TO THE QUICKSILVER RESOURCES SECOND AMENDMENT TO
                  FOURTH AMENDED AND RESTATED CREDIT AGREEMENTEmployment Offer Letter -  Vernon Irvin

 Exhibit 10.1 
  
 May 22, 2003 
  
 Vernon Irvin 
 43714 Moorland Court 
 Leesburg, VA 20176 
  
 Dear Vernon: 
  
 On behalf of VeriSign, Inc., I am pleased to offer you a regular full-time position of Executive Vice President and General Manager of Verisign Telecommunication
Services reporting directly to me. The details of the offer are as follows: 
  
 Annual Salary: $ 350,000.00 (Paid Bi-Weekly) 
  
 Bonus Program: You are eligible to participate in the VeriSign Bonus Program with an annual potential of a bonus targeted at 60% of your base salary. Payment is based on achievement of corporate, division and
individual objectives (prorated based on your start date). For 2003, you are guaranteed a minimum bonus payment of 5/12ths of the annual target. This bonus will be paid after 2003 results are known and audited, which is usually around early March of
the following year. 
  
 Stock Options: I will recommend to
the Board of Directors that you be granted stock options to purchase 150,000 shares of Common Stock. The price of shares will be based on the fair market value on the date of grant. You will be eligible to exercise up to twenty-five percent
(25%) of your total shares one year from the date of grant. Each subsequent quarter (3 months) an additional 6.25% of your total shares will become eligible to exercise while you are employed by VeriSign. 
  
 Sign-on Bonus: In an effort to cover any monetary items you
“leave on the table” at your current employer, plus to cover some of the costs associated with your new position/location, you will be given a $200,000 sign-on bonus (subject to all normal taxes and deductions). One half of this sign-on
bonus ($100,000) will be paid on your first day of employment. The other half ($100,000) will be paid upon your relocation to California. 
  
 Relocation: VeriSign will cover the relocation of you and your family from Leesburg, Virginia to California under the normal VeriSign relocation
program for an employee at your level. A copy of the program particulars is included with this letter. Your relocation is expected to be completed within the first six months of your employment. 
  
 Spouse Career Assistance: VeriSign will provide your spouse with
career assistance services through Spherion, which has offices both in Virginia and California. VeriSign will cover costs up to $10,000, which should be more than adequate to cover your spouse’s immediate needs. 
  
 Severance: Should you be terminated for reasons other than for cause
or resignation, VeriSign will provide you with the following severance benefits: 
  

	 Length of Employment

	  	Months of
Base Salary
Severance

	 One month or less
	  	12 months
	 One to two months
	  	11 months
	 Two to three months
	  	10 months
	 Three to four months
	  	9 months
	 Four to five months
	  	8 months
	 Five to six months
	  	7 months
	 Six months and thereafter
	  	6 months

 Benefits: Your medical and insurance benefits will be commensurate with those of other employees
and will commence effective the first day of your employment. A summary of the full package of benefits is attached. New employees receive 18 days of paid time off per year. VeriSign also observes 10 paid holidays per year. Please Note: Your
benefits information and enrollment directions for 2003 will be mailed to your home shortly after your date of hire. 
  
 This offer is contingent upon your signing the Company’s Confidentiality Agreement included with this offer and upon successful clearance of your background check.
It is also contingent upon providing evidence of your legal right to work in the United States as required by the Immigration and Naturalization Service. This offer is for employment on an at will basis, which means that this relationship can be
terminated at any time by either party. This offer supercedes any and all verbal or written offers or statements by VeriSign and/or its agents. 
  
 To accept this offer, please sign below, indicate your expected start date and return the original offer letter along with the Confidentiality Agreement and VeriSign
application in the enclosed envelope and keep a copy of the offer letter for your records. This offer will expire on May 31, 2003. 
  
 Vernon, I am sincerely pleased to have you part of our executive team and look forward to working with you to face our challenges and celebrate our successes! 

 
 Sincerely, 
  
 /s/ Stratton Sclavos 
  
 Stratton Sclavos 
 Chairman, President & CEO 
  
 Accepted: /s/ Vernon Irvin

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00055-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00055-of-00352.parquet"}]]