<PAGE>

                                                                     Exhibit 4.6






                             MARKEL HOLDINGS INC.

                                      TO

                           THE CHASE MANHATTAN BANK

                                    Trustee


                            CONTINGENT VALUE RIGHTS
                                   AGREEMENT


                                  Dated as of

                                March 15, 2000
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                                TABLE OF CONTENTS
<TABLE>
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<S>                                                                                                       <C>
ARTICLE ONE..............................................................................................   1
DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION..................................................   1
      Section 101.  Definitions..........................................................................   1
         Act.............................................................................................   2
         Affiliate.......................................................................................   2
         Agreement.......................................................................................   2
         Authorized Newspaper............................................................................   2
         Automatic Extinguishment........................................................................   2
         Board of Directors..............................................................................   2
         Board Resolution................................................................................   2
         Business Day....................................................................................   2
         Commission......................................................................................   3
         Company.........................................................................................   3
         Company Request or Company Order................................................................   3
         Control.........................................................................................   3
         Corporate Trust Office..........................................................................   3
         Current Market Value............................................................................   3
         CVR Certificate.................................................................................   3
         Default Amount..................................................................................   3
         Default Interest Rate...........................................................................   3
         Default Payment Date............................................................................   3
         Discounted Target Price.........................................................................   3
         Disposition.....................................................................................   4
         Disposition Payment Date........................................................................   4
         Early Redemption................................................................................   4
         Early Redemption Determination Date.............................................................   4
         Early Redemption Price..........................................................................   4
         Early Redemption Payment Date...................................................................   4
         Effective Time..................................................................................   4
         Events of Default...............................................................................   4
         Exchange Act....................................................................................   4
         Holder..........................................................................................   4
         Independent Financial Expert....................................................................   4
         Maturity Date...................................................................................   4
         Merger Agreement................................................................................   5
         Minimum Price...................................................................................   5
         Nondisposition Event............................................................................   5
         Officer's Certificate...........................................................................   5
         Opinion of Counsel..............................................................................   5
         Outstanding.....................................................................................   5
         Paying Agent....................................................................................   6
         Person..........................................................................................   6
         Responsible Officer.............................................................................   6
</TABLE>

                                       i
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<TABLE>
       <S>                                                                                                    <C>
         Security Register and Security Registrar........................................................    6
         Shares..........................................................................................    6
         Stock...........................................................................................    6
         Surviving Person................................................................................    6
         Target Price....................................................................................    6
         Trust Indenture Act.............................................................................    6
         Trustee.........................................................................................    6
         Valuation Period................................................................................    6
         Value Report....................................................................................    6
         Vice President..................................................................................    6
      Section 102.  Compliance Certificates and Opinions.................................................    6
      Section 103.  Form of Documents Delivered to Trustee...............................................    7
      Section 104.  Acts of Holders......................................................................    8
      Section 105.  Notices, etc., to Trustee and Company................................................    9
      Section 106.  Notice to Holders; Waiver............................................................    9
      Section 107.  Conflict with Trust Indenture Act....................................................    9
      Section 108.  Effect of Headings and Table of Contents............................................    10
      Section 109.  Successors and Assigns..............................................................    10
      Section 110.  Benefits of Agreement...............................................................    10
      Section 111.  Governing Law.......................................................................    10
      Section 112.  Legal Holidays......................................................................    10
      Section 113.  Separability Clause.................................................................    10

ARTICLE TWO.............................................................................................    10
CVR FORMS...............................................................................................    10
      Section 201.  Forms Generally.....................................................................    11
      Section 202.  Form of Face of CVR.................................................................    11
      Section 203.  Form of Reverse of CVR..............................................................    12
      Section 204.  Form of Trustee's Certificate of Authentication.....................................    17

ARTICLE THREE...........................................................................................    17
THE CVRs 17
      Section 301.  Title and Terms.....................................................................    17
      Section 302.  Registrable Form....................................................................    21
      Section 303.  Execution, Authentication, Delivery and Dating......................................    21
      Section 304.  Temporary CVRs......................................................................    22
      Section 305.  Registration, Registration of Transfer and Exchange.................................    23
      Section 306.  Mutilated, Destroyed, Lost and Stolen CVRs..........................................    24
      Section 307.  Presentation of CVR Certificate.....................................................    24
      Section 308.  Persons Deemed Owners...............................................................    25
      Section 309.  Cancellation........................................................................    25

ARTICLE FOUR............................................................................................    25
THE TRUSTEE.............................................................................................    25
      Section 401.  Certain Duties and Responsibilities.................................................    25
      Section 402.  Certain Rights of Trustee...........................................................    26
</TABLE>

                                      ii
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<TABLE>
      <S>                                                                                                   <C>
      Section 403.  Not Responsible for Recitals or Issuance of CVRs....................................    28
      Section 404.  May Hold CVRs.......................................................................    28
      Section 405.  Money Held in Trust.................................................................    28
      Section 406.  Compensation, Reimbursement and Indemnification of the Trustee......................    28
      Section 407.  Disqualification; Conflicting Interests.............................................    29
      Section 408.  Corporate Trustee Required; Eligibility.............................................    29
      Section 409.  Resignation and Removal; Appointment of Successor...................................    30
      Section 410.  Acceptance of Appointment by Successor..............................................    31
      Section 411.  Merger, Conversion, Consolidation or Succession to Business.........................    31

ARTICLE FIVE............................................................................................    32
HOLDERS' LISTS AND REPORTS BY TRUSTEE AND COMPANY.......................................................    32
      Section 501.  Company to Furnish Trustee Names and Addresses of Holders...........................    32
      Section 502.  Preservation of Information; Communications to Holders..............................    32
      Section 503.  Reports by Trustee..................................................................    33
      Section 504.  Reports by Company..................................................................    33

ARTICLE SIX.............................................................................................    34
AMENDMENTS..............................................................................................    34
      Section 601.  Amendments Without Consent of Holders...............................................    34
      Section 602.  Amendments with Consent of Holders..................................................    35
      Section 603.  Execution of Amendments.............................................................    36
      Section 604.  Effect of Amendments................................................................    36
      Section 605.  Conformity with Trust Indenture Act.................................................    36
      Section 606.  Reference in CVRs to Amendments.....................................................    36

ARTICLE SEVEN...........................................................................................    36
COVENANTS...............................................................................................    36
      Section 701.  Payment of Amounts, if Any, to Holders..............................................    36
      Section 702.  Maintenance of Office or Agency.....................................................    36
      Section 703.  Money for CVR Payments to Be Held in Trust..........................................    37
      Section 704.  Certain Purchases and Sales.........................................................    38
      Section 705.  Written Statement to Trustee........................................................    38

ARTICLE EIGHT...........................................................................................    38
REMEDIES OF THE TRUSTEE AND HOLDERS ON EVENT OF DEFAULT.................................................    38
      Section 801.  Event of Default Defined; Acceleration of Maturity; Waiver
                    of Default..........................................................................    38
      Section 802.  Collection of Indebtedness by Trustee; Trustee May Prove Debt.......................    40
      Section 803.  Application of Proceeds.............................................................    42
      Section 804.  Suits for Enforcement...............................................................    42
      Section 805.  Restoration of Rights on Abandonment of Proceedings.................................    43
      Section 806.  Limitations on Suits by Holders.....................................................    43
      Section 807.  Unconditional Right of Holders to Institute Certain Suits...........................    43
      Section 808.  Powers and Remedies Cumulative; Delay or Omission Not
                    Waiver of...........................................................................    43
</TABLE>

                                      iii
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<TABLE>
    <S>                                                                                                   <C>
      Section 809.  Control by Holders..................................................................   44
      Section 810.  Waiver of Past Defaults.............................................................   44
      Section 811.  Trustee to Give Notice of Default, but May Withhold in Certain......................   45
      Section 812.  Right of Court to Require Filing of Undertaking to Pay Costs........................   45

ARTICLE NINE............................................................................................   46
CONSOLIDATION, MERGER, SALE OR CONVEYANCE...............................................................   46
      Section 901.  Company May Consolidate, Etc........................................................   46
      Section 902.  Successor Substituted...............................................................   46
      Section 903.  Opinion of Counsel to Trustee.......................................................   47
</TABLE>

                                      iv
<PAGE>

         AGREEMENT, dated as of March 15, 2000, between Markel Holdings Inc., a
Virginia corporation (hereinafter called the "Company"), and The Chase Manhattan
Bank, trustee (hereinafter called the "Trustee").

                             RECITALS OF THE COMPANY

         WHEREAS, the Company has duly authorized the creation of an issue of
contingent value rights (hereinafter called the "CVRs"), of substantially the
tenor and amount hereinafter set forth, and to provide therefor the Company has
duly authorized the execution and delivery of this Agreement;

         WHEREAS, pursuant to the Agreement and Plan of Merger and Scheme of
Arrangement dated as of August 15, 1999, as amended December 10, 1999 and
further amended as of January 28, 2000 (the "Merger Agreement"), by and between
Markel Corporation ("Markel") and Terra Nova (Bermuda) Holdings Ltd., a Bermuda
corporation ("Terra Nova"), the Company has agreed to issue and deliver to
stockholders of Terra Nova, among other securities, 0.07027 of a CVR for each
Class A and Class B ordinary share, par value $5.80 per share, of Terra Nova
("Terra Nova Share") issued and outstanding immediately prior to the effective
time (the "Effective Time") of the merger (except 2,069 Terra Nova Shares held
by Markel or its transferee); and

         WHEREAS, all things necessary have been done to make the CVRs, when
executed by the Company and authenticated and delivered hereunder, the valid
obligations of the Company and to make this Agreement a valid agreement of the
Company, in accordance with their and its terms.

         NOW, THEREFORE, for and in consideration of the premises and the
consummation of the transactions referred to above, it is mutually covenanted
and agreed, for the equal and proportionate benefit of all Holders of the CVRs,
as follows:

                                   ARTICLE ONE

            DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION

Section 101.  Definitions.

         For all purposes of this Agreement, except as otherwise expressly
provided or unless the context otherwise requires:

                  (a) the terms defined in this Article have the meanings
         assigned to them in this Article, and include the plural as well as the
         singular;

                  (b) all accounting terms used herein and not expressly defined
         shall have the meanings assigned to such terms in accordance with
         generally accepted accounting principles, and the term "generally
         accepted accounting principles" means such accounting principles as are
         generally accepted in the United States of America at the time of any
         computation;

                  (c) all other terms used herein which are defined in the Trust
         Indenture Act, either directly or by reference therein, have the
         meanings assigned to them therein; and

                  (d) the words "herein", "hereof" and "hereunder" and other
         words of similar import refer to this Agreement as a whole and not to
         any particular Article, Section or other subdivision.

         Certain terms, used principally in Article Three, are defined in that
Article.

         "Act", when used with respect to any Holder, has the meaning specified
in Section 104.

                                       1
<PAGE>

         "Affiliate" means, with respect to any Person, any other Person that,
directly or indirectly, through one or more intermediaries, Controls, is
controlled by, or is under common control with, the first mentioned Person.

         "Agreement" means this instrument as originally executed and as it may
from time to time be supplemented or amended pursuant to the applicable
provisions hereof.

         "Authorized Newspaper" means The Wall Street Journal (Eastern Edition),
or if The Wall Street Journal (Eastern Edition) shall cease to be published, or,
if the publication or general circulation of The Wall Street Journal (Eastern
Edition) shall be suspended for whatever reason, such other English language
newspaper as is selected by the Company with general circulation in The City of
New York, New York.

         "Automatic Extinguishment" has the meaning set forth in Section 301(l).

         "Board of Directors" means either the board of directors of the Company
or any duly authorized committee of that board.

         "Board Resolution" means a copy of a resolution certified by the
Secretary or an Assistant Secretary of the Company to have been duly adopted by
the Board of Directors and to be in full force and effect on the date of such
certification, and delivered to the Trustee.

         "Business Day" means any day (other than a Saturday or a Sunday) on
which banking institutions in The City of New York, New York or in the State of
the principal office of the Trustee are not authorized or obligated by law or
executive order to close and, if the CVRs are listed on a national securities
exchange, such exchange is open for trading.

         "Cash" has the meaning set forth in Section 202.

         "Commission" means the Securities and Exchange Commission, as from time
to time constituted, created under the Exchange Act, or if at any time after the
execution of this Agreement such Commission is not existing and performing the
duties now assigned to it under the Trust Indenture Act, then the body
performing such duties at such time.

         "Company" means the Person named as the "Company" in the first
paragraph of this Agreement, until a successor Person shall have become such
pursuant to the applicable provisions of this Agreement, and thereafter
"Company" shall mean such successor Person. To the extent necessary to comply
with the requirements of the provisions of Trust Indenture Act Sections 310
through 317 as they are applicable to the Company, the term "Company" shall
include any other obligor with respect to the CVRs for the purposes of complying
with such provisions.

         "Company Request" or "Company Order" means a written request or order
signed in the name of the Company by the chairman or vice chairman of the Board
of Directors, the president, any vice president, the controller, the treasurer,
the secretary or any assistant secretary, and delivered to the Trustee.

         "Control" (including the terms "controlled", "controlled by" and "under
common control with") means the possession, directly or indirectly or as trustee
or executor, of the power to direct or cause the direction of the management or
policies of a Person, whether through the ownership of stock or as trustee or
executor, by contract or otherwise.

         "Corporate Trust Office" means the office of the Trustee at which at
any particular time its corporate trust business shall be principally
administered, which office at the date of execution of this Agreement is located
at 450 West 33rd Street, New York, New York 10001.

         "Current Market Value" has the meaning set forth in Section 301(g).

         "CVR Certificate" means a certificate representing any of the CVRs.

                                       2
<PAGE>

         "Default Amount" means the amount, if any, by which the Discounted
Target Price exceeds the Minimum Price.

         "Default Interest Rate" means 6% per annum.

         "Default Payment Date" means the date upon which the CVRs become due
and payable pursuant to Section 801.

         "Discounted Target Price" means, if a Disposition or an Event of
Default shall occur prior to the Maturity Date, $185.00 discounted from the
Maturity Date back to the Disposition Payment Date or the Default Payment Date,
as the case may be, at a per annum rate of 6%. In each case, upon each
occurrence of an event specified in Section 301(k), such amount, as it may have
been previously adjusted, shall be adjusted pursuant to Section 301(k).

         "Disposition" means (i) a merger, consolidation or other business
combination involving the Company as a result of which no Shares shall remain
outstanding (other than any Shares owned by the Company or any other obligor
upon the CVRs or any Affiliate of the Company or any such other obligor), (ii) a
sale, transfer or other disposition, in one or a series of transactions, of all
or substantially all of the assets of the Company or (iii) a reclassification of
Shares as any other capital stock of the Company or any other Person; unless in
the case of clauses (i) and (ii) such transaction is in connection with a
transaction in which all of the Shares are exchanged solely for other publicly
traded equity securities of the Company or another Person, the successor assumes
the obligations of the Company relating to the CVRs, and appropriate adjustments
are made to the Target Price, the Minimum Price, the Discounted Target Price and
other terms hereof to reflect such transaction and the economic benefits
intended to be conferred on the CVRs under this Agreement (a "Nondisposition
Event").

         "Disposition Payment Date" has the meaning set forth in Section 301(e).

         "Early Redemption" has the meaning set forth in Section 203.

         "Early Redemption Determination Date" means the date five Business Days
prior to the date, if any, upon which the Company issues a notice of redemption
of the CVRs prior to the Maturity Date pursuant to Section 301(d).

         "Early Redemption Payment Date" means the date upon which the Early
Redemption Price is paid to the Trustee in connection with an Early Redemption,
which shall also be the redemption date.

         "Early Redemption Price" has the meaning set forth in Section 301(d).

         "Effective Time" has the meaning set forth in the Preamble.

         "Event of Default" has the meaning set forth in Section 801.

         "Exchange Act" means the Securities Exchange Act of 1934, as amended.

         "Holder" means a Person in whose name a CVR is registered in the
Security Register.

         "Independent Financial Expert" means an independent nationally
recognized investment-banking firm.

         "Maturity Date" means the date that is the first day after the
expiration of thirty (30) months from the Effective Time.

         "Merger Agreement" has the meaning as set forth in the preamble.

                                       3
<PAGE>

         "Minimum Price" means $140.00. In each case, upon each occurrence of an
event specified in Section 301(k), such amount, as it may have been previously
adjusted, shall be adjusted pursuant to Section 301(k).

         "Nondisposition Event" has the meaning as set forth in the definition
of "Disposition".

         "Officer's Certificate" means a certificate signed by the chairman or
vice chairman of the Board of Directors, the president, any vice president, the
controller, the treasurer, the secretary or any assistant secretary of the
Company in his or her capacity as such an officer, and delivered to the Trustee.

         "Opinion of Counsel" means a written opinion of counsel, who may be
General Counsel for the Company, and who shall be reasonably acceptable to the
Trustee.

         "Outstanding", when used with respect to CVRs, means, as of the date of
determination, all CVRs theretofore authenticated and delivered under this
Agreement, except:

                  (a) CVRs theretofore cancelled by the Trustee or delivered to
         the Trustee for cancellation;

                  (b) From and after the earlier of the Default Payment Date,
         the Disposition Payment Date, the Early Redemption Payment Date or the
         Maturity Date, CVRs, or portions thereof, for whose payment in cash or
         securities of the Company in the necessary amount has been theretofore
         deposited with the Trustee or any Paying Agent (other than the Company)
         in trust or set aside and segregated in trust by the Company (if the
         Company shall act as its own Paying Agent) for the Holders of such
         CVRs; and

                  (c) CVRs in exchange for or in lieu of which other CVRs have
         been authenticated and delivered pursuant to this Agreement, other than
         any such CVRs in respect of which there shall have been presented to
         the Trustee proof satisfactory to it that such CVRs are held by a
         protected purchaser in whose hands the CVRs are valid obligations of
         the Company;

provided, however, that in determining whether the Holders of the requisite
Outstanding CVRs have given any request, demand, direction, consent or waiver
hereunder, CVRs owned by the Company or any other obligor upon the CVRs or any
Affiliate of the Company or such other obligor shall be disregarded and deemed
not to be Outstanding, except that, in determining whether the Trustee shall be
protected in relying upon any such request, demand, direction, consent or
waiver, only CVRs which a Responsible Officer of the Trustee knows to be so
owned shall be so disregarded.

         "Paying Agent" means any Person authorized by the Company to pay the
amount determined pursuant to Section 301, if any, on any CVRs on behalf of the
Company, which shall initially be the Trustee.

         "Person" means any individual, corporation, partnership, joint venture,
limited liability company, association, joint-stock company, trust,
unincorporated organization or government or any agency or political subdivision
thereof.

         "Responsible Officer", when used with respect to the Trustee, means any
officer with direct responsibility for the administration of this Agreement and
also means, with respect to any particular corporate trust matter, any other
officer of the Trustee to whom such matter is referred because of his knowledge
of and familiarity with the particular subject.

         "Security Register" and "Security Registrar" have the respective
meanings specified in Section 305.

         "Shares" means the common shares, no par value, of the Company.

                                       4
<PAGE>

         "Stock" has the meaning as set forth in Section 202.

         "Surviving Person" has the meaning set forth in Section 901.

         "Target Price" means $185.00. In each case, upon each occurrence of an
event specified in Section 301(k), such amount, as it may have been previously
adjusted, shall be adjusted pursuant to Section 301(k).

          "Trust Indenture Act" means the Trust Indenture Act of 1939 as in
force at the date as of which this Agreement was executed, except as provided in
Section 605.

         "Trustee" means the Person named as the "Trustee" in the first
paragraph of this Agreement, until a successor Trustee shall have become such
pursuant to the applicable provisions of this Agreement, and thereafter
"Trustee" shall mean such successor Trustee.

         "Valuation Period" has the meaning set forth in Section 301(g).

         "Value Report" has the meaning set forth in Section 301(h).

         "Vice President", when used with respect to the Company or the Trustee,
means any vice president, whether or not designated by a number or a word or
words added before or after the title of "vice president".

Section 102.  Compliance Certificates and Opinions.

         Upon any application or request by the Company to the Trustee to take
any action under any provision of this Agreement, the Company shall furnish to
the Trustee an Officer's Certificate stating that all conditions precedent, if
any, provided for in this Agreement (including any covenants, compliance with
which constitutes a condition precedent) relating to the proposed action have
been complied with and an Opinion of Counsel stating that in the opinion of such
counsel all such conditions precedent, if any, have been complied with, except
that, in the case of any such application or request as to which the furnishing
of such documents is specifically required by any provision of this Agreement
relating to such particular application or request, no additional certificate or
opinion need be furnished.

         Every certificate or opinion with respect to compliance with a
condition or covenant provided for in this Agreement shall include:

                  (a) a statement that each individual signing such certificate
         or opinion has read such covenant or condition and the definitions
         herein relating thereto;

                  (b) a brief statement as to the nature and scope of the
         examination or investigation upon which the statements or opinions
         contained in such certificate or opinion are based;

                  (c) a statement that, in the opinion of each such individual,
         he has made such examination or investigation as is necessary to enable
         him to express an informed opinion as to whether or not such covenant
         or condition has been complied with; and

                  (d) a statement as to whether, in the opinion of each such
         individual, such condition or covenant has been complied with.

Section 103.  Form of Documents Delivered to Trustee.

         In any case where several matters are required to be certified by, or
covered by an opinion of, any specified Person, it is not necessary that all
such matters be certified by, or covered by the opinion of, only one such
Person, or that they be so certified or covered by only one document, but one
such Person may

                                       5
<PAGE>

certify or give an opinion with respect to some matters and one or more other
such Persons as to other matters, and any such Person may certify or give an
opinion as to such matters in one or several documents.

         Any certificate or opinion of an officer of the Company may be based,
insofar as it relates to legal matters, upon a certificate or opinion of, or
representations by, counsel, unless such officer knows, or in the exercise of
reasonable care should know, that the certificate or opinion or representations
with respect to the matters upon which his certificate or opinion is based are
erroneous. Any such certificate or Opinion of Counsel may be based, insofar as
it relates to factual matters, upon a certificate or opinion of, or
representations by, an officer or officers of the Company stating that the
information with respect to such factual matters is in the possession of the
Company, unless such counsel knows, or in the exercise of reasonable care should
know, that the certificate or opinion or representations with respect to such
matters are erroneous.

         Any certificate, statement or opinion of an officer of the Company or
of counsel may be based, insofar as it relates to accounting matters, upon a
certificate or opinion of or representations by an accountant or firm of
accountants in the employ of the Company, unless such officer or counsel, as the
case may be, knows that the certificate or opinion or representations with
respect to the accounting matters upon which his certificate, statement or
opinion may be based as aforesaid are erroneous, or in the exercise of
reasonable care should know that the same are erroneous. Any certificate or
opinion of any independent firm of public accountants filed with the Trustee
shall contain a statement that such firm is independent.

         Where any Person is required to make, give or execute two or more
applications, requests, consents, certificates, statements, opinions or other
instruments under this Agreement, they may, but need not, be consolidated and
form one instrument.

Section 104.  Acts of Holders.

         (a) Any request, demand, authorization, direction, notice, consent,
waiver or other action provided by this Agreement to be given or taken by
Holders may be embodied in and evidenced by one or more instruments of
substantially similar tenor signed by such Holders in person or by an agent duly
appointed in writing; and, except as herein otherwise expressly provided, such
action shall become effective when such instrument or instruments are delivered
to the Trustee and, where it is hereby expressly required, to the Company. Such
instrument or instruments (and the action embodied therein and evidenced
thereby) are herein sometimes referred to as the "Act" of the Holders signing
such instrument or instruments. Proof of execution of any such instrument or of
a writing appointing any such agent shall be sufficient for any purpose of this
Agreement and (subject to Section 401) conclusive in favor of the Trustee and
the Company, if made in the manner provided in this Section.

         (b) The fact and date of the execution by any Person of any such
instrument or writing may be proved in any reasonable manner that the Trustee
deems sufficient.

         (c)  The ownership of CVRs shall be proved by the Security Register.

         (d) At any time prior to (but not after) the evidencing to the Trustee,
as provided in this Section 104, of the taking of any action by the Holders of
the CVRs specified in this Agreement in connection with such action, any Holder
of a CVR may, by filing written notice at the Corporate Trust Office and upon
proof of holding as provided in this Section 104, revoke such action so far as
it concerns such CVR. Any request, demand, authorization, direction, notice,
consent, waiver or other action by the Holder of any CVR shall bind every future
Holder of the same CVR or the Holder of every CVR issued upon the registration
of transfer thereof or in exchange therefor or in lieu thereof, in respect of
anything done, suffered or omitted to be done by the Trustee, any Paying Agent
or the Company in reliance thereon, whether or not notation of such action is
made upon such CVR.

Section 105.  Notices, etc., to Trustee and Company.

                                       6
<PAGE>

         Any request, demand, authorization, direction, notice, consent, waiver
or Act of Holders or other document provided or permitted by this Agreement to
be made upon, given or furnished to, or filed with:

                  (a)  the Trustee by any Holder or by the Company shall be
         sufficient for every purpose hereunder if made, given, furnished or
         filed, in writing, to or with the Trustee at its Corporate Trust
         Office, Attention: Capital Markets Fiduciary Services.

                  (b)  the Company by the Trustee or by any Holder shall be
         sufficient for every purpose hereunder if in writing and mailed,
         first-class postage prepaid, to the Company addressed to it at 4521
         Highwoods Parkway, Glen Allen, Virginia 23060, Attention: Steven A.
         Markel and Gregory B. Nevers, or at any other address previously
         furnished in writing to the Trustee by the Company.

Section 106.  Notice to Holders; Waiver.

         Where this Agreement provides for notice to Holders of any event, such
notice shall be sufficiently given (unless otherwise herein expressly provided)
if in writing and mailed, first-class postage prepaid, to each Holder affected
by such event, at his address as it appears in the Security Register, not later
than the latest date, and not earlier than the earliest date, prescribed for the
giving of such notice. In any case where notice to Holders is given by mail,
neither the failure to mail such notice, nor any defect in any notice so mailed,
to any particular Holder shall affect the sufficiency of such notice with
respect to other Holders. Where this Agreement provides for notice in any
manner, such notice may be waived in writing by the Person entitled to receive
such notice, either before or after the event, and such waiver shall be the
equivalent of such notice. Waivers of notice by Holders shall be filed with the
Trustee, but such filing shall not be a condition precedent to the validity of
any action taken in reliance upon such waiver.

         In case by reason of the suspension of regular mail service or by
reason of any other cause, it shall be impracticable to mail notice of any event
as required by any provision of this Agreement, then any method of giving such
notice as shall be satisfactory to the Trustee shall be deemed to be a
sufficient giving of such notice.

Section 107.  Conflict with Trust Indenture Act.

         If any provision hereof limits, qualifies or conflicts with another
provision hereof which is required to be included in this Agreement by any of
the provisions of the Trust Indenture Act, such required provision shall
control.

Section 108.  Effect of Headings and Table of Contents.

         The Article and Section headings herein and the Table of Contents are
for convenience only and shall not affect the construction hereof.

Section 109.  Successors and Assigns.

         All covenants and agreements in this Agreement by the Company shall
bind its successors and assigns, whether so expressed or not.

Section 110.  Benefits of Agreement.

         Nothing in this Agreement or in the CVRs, express or implied, shall
give to any Person (other than the parties hereto and their successors
hereunder, any Paying Agent and the Holders) any benefit or any legal or
equitable right, remedy or claim under this Agreement or under any covenant or
provision herein contained, all such covenants and provisions being for the sole
benefit of the parties hereto and their successors and of the Holders.

Section 111.  Governing Law.

                                       7
<PAGE>

         This Agreement and the CVRs shall be governed by and construed in
accordance with the laws of the Commonwealth of Virginia, except as to the
standard of care applicable to the Trustee which shall be governed by the laws
of the State of New York.

Section 112.  Legal Holidays.

         In the event that the Maturity Date, the Disposition Payment Date, the
Early Redemption Payment Date or the Default Payment Date, as the case may be,
shall not be a Business Day, then (notwithstanding any provision of this
Agreement or the CVRs to the contrary) payment on the CVRs need not be made on
such date, but may be made on the next succeeding Business Day with the same
force and effect as if made on the Maturity Date, the Disposition Payment Date,
the Early Redemption Payment Date or the Default Payment Date, as the case may
be.

Section 113.  Separability Clause.

         In case any provision in this Agreement or in the CVRs shall be
invalid, illegal or unenforceable, the validity, legality and enforceability of
the remaining provisions shall not in any way be affected or impaired thereby.

                                  ARTICLE TWO

                                   CVR FORMS

Section 201.  Forms Generally.

         The CVRs and the Trustee's certificate of authentication shall be in
substantially the forms set forth in this Article, with such appropriate
insertions, omissions, substitutions and other variations as are required or
permitted by this Agreement and may have such letters, numbers or other marks of
identification and such legends or endorsements placed thereon as may be
required to comply with the rules of any securities exchange or as may be
required by law or any rule or regulation pursuant thereto, all as may be
determined by officers executing such CVRs, as evidenced by their execution of
the CVRs. Any portion of the text of any CVR may be set forth on the reverse
thereof, with an appropriate reference thereto on the face of the CVR.

         The definitive CVRs shall be printed, lithographed or engraved or
produced by any combination of these methods or may be produced in any other
manner as determined by the officers executing such CVRs, as evidenced by their
execution of such CVRs.

Section 202.  Form of Face of CVR.

                               <NAME OF COMPANY>

No. CVRs __________       Certificate for Contingent Value Rights

         This certifies that __________________ or registered assigns (the
"Holder") is the registered holder of the number of Contingent Value Rights
("CVRs") set forth above. Each CVR entitles the Holder, subject to the
provisions contained herein and in the Agreement referred to on the reverse
hereof, to a payment from <Name of Company>, a Virginia corporation (the
"Company"), in an amount and in the form determined pursuant to the provisions
set forth on the reverse hereof and as more fully described in the Agreement.
Such payment shall be made, if in Cash (as defined below) on the third Business
Day following, or if in Stock (as defined below) as promptly as practicable
after, the Maturity Date, or on the Default Payment Date or the Early Redemption
Payment Date or the Disposition Payment Date upon the occurrence of an Event of
Default or a Disposition, as the case may be, each as defined in the Agreement
referred to on the reverse hereof.

                                       8
<PAGE>

         Payment of any amounts pursuant to this CVR Certificate shall be made
only upon presentation of this CVR Certificate by the Holder hereof, at the
office or agency of the Company maintained for that purpose. Such payment,
including payments after a Disposition, Event of Default or Early Redemption,
shall be made in the Borough of Manhattan, The City of New York, or at any other
office or agency maintained by the Company for such purpose either, in the
Company's sole discretion, (i) in such coin or currency of the United States of
America as at the time is legal tender for the payment of public and private
debts; provided, however, the Company may pay such amounts by its check payable
in such money ("Cash") or (ii) by delivering the equivalent fair market value of
Shares, valued at the mean of the averages of the high and low and opening and
closing prices on the New York Stock Exchange (or, if the Shares are not listed
thereon, the principal other exchange upon which such shares are then listed) of
Shares during the 20 consecutive trading day period ending on the date preceding
the date the amounts are due ("Stock"). The Chase Manhattan Bank has been
appointed as Paying Agent in the Borough of Manhattan, The City of New York.

         Reference is hereby made to the further provisions of this CVR
Certificate set forth on the reverse hereof, which further provisions shall for
all purposes have the same effect as if set forth at this place.

         Unless the certificate of authentication hereon has been duly executed
by the Trustee referred to on the reverse hereof by manual signature, this CVR
Certificate shall not be entitled to any benefit under the Agreement or be valid
or obligatory for any purpose.

         IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed under its corporate seal.

Dated:                                              <NAME OF COMPANY>



                                           By:      ________________________
                                                    Name:
                                                    Title:
Attest:
SEAL


_______________________________
Name:
Title:


Section 203.  Form of Reverse of CVR.

         This CVR Certificate is issued under and in accordance with the
Contingent Value Rights Agreement, dated as of March 15, 2000 (the "Agreement"),
between the Company and The Chase Manhattan Bank, trustee (the "Trustee", which
term includes any successor Trustee under the Agreement), and is subject to the
terms and provisions contained in the Agreement, all of which terms and
provisions the Holder of this CVR Certificate consents by acceptance hereof. The
Agreement is hereby incorporated herein by reference and made a part hereof.
Reference is hereby made to the Agreement for a full statement of the respective
rights, limitations of rights, duties, obligations and immunities thereunder of
the Company, the Trustee and the Holders of the CVRs. Copies of the Agreement
can be obtained by contacting the Company.

         Subject to adjustment pursuant to Section 301(k) of the Agreement, and
subject to Section 301(l) of the Agreement, the Company shall pay to the Holder
hereof, if in Cash, on the third Business Day following, or if in Stock as
promptly as practicable after, ______________ (the "Maturity Date"), an

                                       9
<PAGE>

amount, if any, as determined by the Company, by which the Target Price exceeds
the greater of (i) the Current Market Value and (ii) the Minimum Price. Such
determination by the Company absent manifest error shall be final and binding on
the Company and the Holder.

         Such amount, if any, shall be payable by the Company, either, in the
Company's sole discretion, in (i) Cash or (ii) Stock. The Chase Manhattan Bank
has been appointed as Paying Agent in the Borough of Manhattan, The City of New
York. All payments to be made by the Company pursuant to this CVR Certificate
shall be subject to and reduced by withholding taxes, if any. The Company shall
have no obligation to reimburse, equalize, or compensate a Holder or other
Person for such withholding taxes.

         The Company may redeem all, but not less than all, of the CVRs at any
time upon not less than 30 days notice at a price per CVR (the "Early Redemption
Price") equal to the difference between the Target Price and the Current Market
Value as at the Early Redemption Determination Date, discounted from the
Maturity Date to the Early Redemption Payment Date at a per annum rate of 6% (an
"Early Redemption"). The Early Redemption Price shall be payable by the Company
in the Company's sole discretion either in (i) Cash or (ii) Stock. Nothing in
the Agreement shall limit the Company's ability to purchase or otherwise acquire
CVRs through open market transactions, privately negotiated transactions, or
otherwise.

         Upon the consummation of a Disposition, the Company shall pay to the
Holder hereof (in Cash or Stock, at the Company's sole discretion) for each CVR
represented hereby an amount, if any, as determined by the Company, by which the
Discounted Target Price exceeds the greater of (i) the fair market value, as
determined by an Independent Financial Expert, of the consideration, if any,
received for each Share by the holder thereof as a result of such Disposition,
assuming that such holder did not exercise any right of appraisal granted under
law with respect to such Disposition, and (ii) the Minimum Price. Such
determinations by the Company and such Independent Financial Expert absent
manifest error shall be final and binding on the Company and the Holder. Such
payment shall be made on the date (the "Disposition Payment Date") established
by the Company, which in no event shall be more than 30 days after the date on
which the Disposition was consummated. As soon as practicable after the
Disposition, the Company shall give the Holder hereof and the Trustee written
notice of such Disposition and the Disposition Payment Date, as provided in
Section 301(e) of the Agreement.

         If an Event of Default occurs and is continuing, either the Trustee or
the Holders holding an aggregate of at least 25% of the Outstanding CVRs, by
notice to the Company (and to the Trustee if given by the Holders), may declare
the CVRs due and payable, and upon such declaration, the Company shall pay to
the Holder (in Cash or Stock, at the Company's sole discretion) for each CVR
held by the Holder the Default Amount with interest at a rate of 6% per annum
from the Default Payment Date through the date payment is made or duly provided
for.

         In the event that the Company determines that no amount is payable on
the CVRs to the Holder on the Maturity Date or the Disposition Payment Date, as
the case may be, as a result of Automatic Extinguishment or otherwise, the
Company shall give to the Holder and the Trustee written notice of such
determination. Upon making such determination, absent manifest error, this CVR
Certificate shall terminate and become null and void and the Holder hereof shall
have no further rights with respect hereto. The failure to give such notice or
any defect therein shall not affect the validity of such determination.

         If the Current Market Value of the Company's Shares during any 20
consecutive trading days in the Valuation Period is greater than or equal to
$185.00 per Share, the CVRs will automatically be extinguished without further
consideration or action by the Company or the Holders ("Automatic
Extinguishment").

         Notwithstanding any provision of the Agreement or of this CVR
Certificate to the contrary, other than in the case of interest on the Default
Amount, no interest shall accrue on any amounts payable on the CVRs to the
Holder.

         "Authorized Newspaper" means The Wall Street Journal (Eastern Edition),
or if The Wall Street Journal (Eastern Edition) shall cease to be published, or,
if the publication or general circulation of The

                                       10
<PAGE>

Wall Street Journal (Eastern Edition) shall be suspended for whatever reason,
such other English language newspaper as is selected by the Company with general
circulation in The City of New York, New York.

         "Current Market Value" shall be, during the 20 consecutive trading day
period that both begins and ends in the Valuation Period and which yields the
highest such averages for any such 20 consecutive trading day period within the
Valuation Period: (i) the mean of the averages of the high and low and opening
and closing prices, regular way, on the New York Stock Exchange (or, if the
Shares are not listed thereon, the principal other exchange on which such shares
are then listed); (ii) if the Shares are not then listed or admitted to trading
on any securities exchange, the mean of the averages of the high and low and
opening and closing sale price on such days, or if no sale takes place on such
days, the mean of the averages of the high and low and opening and closing bid
and asked prices on such days, as reported by a reputable quotation source
designated by the Company; or (iii) if the Shares are not then listed or
admitted to trade on any securities exchange and no such reported sale price or
bid and asked prices are available, the mean of the averages of the reported
high and low and opening and closing bid and asked prices on those days on which
such information is available, as reported in the Authorized Newspaper.
Notwithstanding the foregoing, in computing Current Market Value for purposes of
an Early Redemption or the Automatic Extinguishment, no such 20 consecutive day
period may be included in which the Company, any of its subsidiaries or
controlled Affiliates or Steven A. Markel, Anthony F. Markel or Alan I. Kirshner
purchase any Shares, except (x) in privately negotiated transactions that are
not reported to any exchange (other than as a result of being disclosed in a
filing with the Commission that is also required to be filed with such
exchange), (y) with respect to employee benefit plans and other incentive
compensation arrangements in the ordinary course of business and (z) purchases
in compliance with Rule 10b-18 promulgated under the Exchange Act.

         "Default Amount" means the amount, if any, by which the Discounted
Target Price exceeds the Minimum Price.

         "Default Payment Date" means the date upon which the CVRs become due
and payable pursuant to Section 801 of the Agreement.

         "Discounted Target Price" means, if a Disposition or an Event of
Default shall occur prior to the Maturity Date, $185.00 discounted from the
Maturity Date back to the Disposition Payment Date or the Default Payment Date,
as the case may be, at a per annum rate of 6%. In each case, upon each
occurrence of an event specified in Section 301(k) of the Agreement, such
amount, as it may have been previously adjusted, shall be adjusted pursuant to
Section 301(k) of the Agreement.

         "Disposition" means (i) a merger, consolidation or other business
combination involving the Company as a result of which no Shares shall remain
outstanding (other than any Shares owned by the Company or any other obligor
upon the CVRs or any Affiliate of the Company or any such other obligor), (ii) a
sale, transfer or other disposition, in one or a series of transactions, of all
or substantially all of the assets of the Company or (iii) a reclassification of
Shares as any other capital stock of the Company or any other Person; unless in
the case of clauses (i) and (ii) such transaction is in connection with a
transaction in which all of the Shares are exchanged solely for other publicly
traded equity securities of the Company or another Person, the successor assumes
the obligations of the Company relating to the CVRs, and appropriate adjustments
are made to the Target Price, the Minimum Price, the Discounted Target Price and
other terms hereof to reflect such transaction and the economic benefits
intended to be conferred on the CVRs under this Agreement (a "Nondisposition
Event").

         "Early Redemption Determination Date" means the date five Business Days
prior to the date, if any, upon which the Company issues a notice of redemption
of the CVRs prior to the Maturity Date.

         "Event of Default" has the meaning set forth in Section 801 of the
Agreement.

         "Independent Financial Expert" means an independent nationally
recognized investment-banking firm.

                                       11
<PAGE>

         The "Minimum Price" means $140.00. In each case, upon each occurrence
of an event specified in Section 301(k) of the Agreement, such amount, as it may
have been previously adjusted, shall be adjusted pursuant to Section 301(k) of
the Agreement.

         "Shares" means the common shares, no par value, of the Company.

         The "Target Price" means $185.00. In each case, upon each occurrence of
an event specified in Section 301(k) of the Agreement, such amount, as it may
have been previously adjusted, shall be adjusted pursuant to Section 301(k) of
the Agreement.

         "Valuation Period" has the meaning specified in Section 301(g) of the
Agreement.

         The Agreement 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 CVRs under the Agreement at any time by
the Company and the Trustee with the consent of the Holders of a majority of the
CVRs at the time outstanding.

         No reference herein to the Agreement and no provision of this CVR
Certificate or of the Agreement shall alter or impair the obligation of the
Company, which is absolute and unconditional, to pay any amounts determined
pursuant to the terms hereof and of the Agreement at the times, place, and
amount, and in the Cash or Stock, herein prescribed.

         As provided in the Agreement and subject to certain limitations therein
set forth, the transfer of the CVRs represented by this CVR Certificate is
registerable on the Security Register of the Company, upon surrender of this CVR
Certificate for registration of transfer at the office or agency of the Company
maintained for such purpose in the City of New York, duly endorsed by, or
accompanied by a written instrument of transfer in form satisfactory to the
Company and the Security Registrar duly executed by, the Holder hereof or his
attorney duly authorized in writing, and thereupon one or more new CVR
Certificates, for the same amount of CVRs, will be issued to the designated
transferee or transferees. The Company hereby initially designates the principal
corporate trust office of the Trustee as the office for registration of transfer
of this CVR Certificate.

         As provided in the Agreement and subject to certain limitations therein
set forth, this CVR Certificate is exchangeable for one or more CVR Certificates
representing the same number of CVRs as represented by this CVR Certificate as
requested by the Holder surrendering the same.

         No service charge will be made for any registration of transfer or
exchange of CVRs, but the Company may require payment of a sum sufficient to
cover any tax or other governmental charge payable in connection therewith.

         Prior to the time of due presentment of this CVR Certificate for
registration of transfer, the Company, the Trustee and any agent of the Company
or the Trustee may treat the Person in whose name this CVR Certificate is
registered as the owner hereof for all purposes, and neither the Company, the
Trustee nor any agent shall be affected by notice to the contrary.

         All capitalized terms used in this CVR Certificate without definition
shall have the meanings assigned to them in the Agreement.

Section 204.  Form of Trustee's Certificate of Authentication.

                   TRUSTEE'S CERTIFICATE OF AUTHENTICATION.

         This is one of the CVR Certificates referred to in the within-mentioned
Agreement.

                           The Chase Manhattan Bank

                                       12
<PAGE>

                                     Trustee

                             By_____________________
                                Authorized Officer

                                  ARTICLE THREE

                                    THE CVRs

Section 301.  Title and Terms.

         (a) The aggregate number of CVR Certificates which may be authenticated
and delivered under this Agreement is limited to 1,800,000, except for CVRs
authenticated and delivered upon registration of transfer of, or in exchange
for, or in lieu of, other CVRs pursuant to Section 304, 305, 306 or 606 of this
Agreement. The Company will not issue any fractional CVRs.

         (b) The CVRs shall be known and designated as the "Contingent Value
Rights" of the Company and shall be unsecured obligations of the Company that
rank equally with all other unsecured obligations of the Company and the Holders
shall have no rights except for those rights explicitly provided for herein and
shall not, by virtue of their ownership of CVRs, have any of the rights of a
shareholder of the Company.

         (c) Subject to adjustment pursuant to Section 301(k) and subject to
Section 301(l), the Company shall pay to each Holder, if in Cash, on the third
Business Day following the Maturity Date, or if in Stock, as promptly as
practicable after the Maturity Date, for each CVR held by such Holder, an
amount, if any, as determined by the Company, by which the Target Price exceeds
the greater of (i) the Current Market Value and (ii) the Minimum Price. Such
determinations by the Company absent manifest error shall be final and binding
on the Company and the Holders. Not later than the second Business Day after the
Maturity Date, the Company shall (x) prepare and file with the Trustee a
certificate setting forth such determinations (including, if the amount payable
is to be paid in Stock, the Company's calculation of the amount of Stock to be
paid) and the facts accounting for such determinations and (y) mail to each
Holder a brief summary of such certificate, stating whether the amount payable
will be paid in Cash or Stock, and indicating the locations at which CVRs may be
presented for payment. The Company shall certify the actual date of the Maturity
Date to the Trustee in an Officers' Certificate delivered to the Trustee within
thirty (30) days after the Effective Time.

         (d) The Company may redeem all, but not less than all, of the CVRs at
any time upon not less than 30 Business Days notice at a price per CVR (the
"Early Redemption Price") equal to the difference between the Target Price and
the Current Market Value as at the Early Redemption Determination Date,
discounted from the Maturity Date to the Early Redemption Payment Date at a per
annum rate of 6% (an "Early Redemption"). The Early Redemption Price shall be
payable by the Company in the Company's sole discretion either in (i) Cash or
(ii) Stock. Such option shall be exercised by (i) publishing notice of such
redemption in the Authorized Newspaper and (ii) furnishing notice, in the form
set forth below, to the Trustee and each Holder of such redemption, in each
case, not less than thirty (30) Business Days before the redemption date;
provided, that no defect in any such notice shall affect the validity of the
redemption, and that any notice when published and mailed to the Trustee and a
Holder in the aforesaid manner shall be conclusively deemed to have been
received by such Holder whether or not actually received by such Holder. Nothing
in this Agreement shall limit the Company's ability to purchase or otherwise
acquire CVRs through open market transactions, privately negotiated
transactions, or otherwise.

                                 * * * * * * *

                                       13
<PAGE>

                             MARKEL HOLDINGS INC.

                            CONTINGENT VALUE RIGHTS

                                    [DATE]

                             NOTICE OF REDEMPTION

         NOTICE IS HEREBY GIVEN THAT, pursuant to Section 301 of the Contingent
Value Rights Agreement, dated as of March 15, 2000 (the "Agreement"), between
Markel Holdings Inc. (the "Company") and The Chase Manhattan Bank, as trustee
(the "Trustee"), the Company has redeemed the Contingent Value Rights. All terms
used in this Notice that are defined in the Agreement shall have the meanings
assigned to them in the Agreement. Each and every currently outstanding CVR will
be redeemed at a price equal to the difference between the [TARGET PRICE] and
the current market value of a Share as of [DATE], discounted from [MATURITY
DATE] to [EARLY REDEMPTION PAYMENT DATE] at a per annum rate of 6%, less
applicable withholding taxes, if any.

                                 * * * * * * *
Promptly after the Early Redemption Payment Date, the Company shall (x) prepare
and file with the Trustee an Officers' Certificate setting forth the Company's
determination of the Early Redemption Price (including, if the amount payable is
to be paid in Stock, the Company's calculation of the amount of Stock to be
paid) and the facts accounting for such determination and (y) mail to each
Holder a brief summary of such certificate, indicating the locations at which
CVRs may be presented for payment.

         (e) Upon the consummation of a Disposition, the Company shall pay (in
the manner provided in Section 307) to each Holder for each CVR held by such
Holder an amount, if any, as determined by the Company, by which the Discounted
Target Price exceeds the greater of (i) the cash amount received for each Share
by the holder thereof as a result of such Disposition, plus the fair market
value, as determined by an Independent Financial Expert, of the non-cash
consideration, if any, received for each Share by the holder thereof as a result
of such Disposition, assuming that such Holder did not exercise any right of
appraisal granted under law with respect to such Disposition, and (ii) the
Minimum Price. Such determinations by the Company and such Independent Financial
Expert absent manifest error shall be final and binding on the Company and the
Holders. Such payment shall be made on the date (the "Disposition Payment Date")
established by the Company, which in no event shall be more than 30 days after
the date on which the Disposition was consummated.

         (f) As soon as practicable, the Company shall (x) prepare and file with
the Trustee an Officers' Certificate setting forth the determinations referred
to in Section 301(e) (including, if the amount payable is to be paid in Stock,
the Company's calculation of the amount of Stock to be paid) and the facts
accounting for such determinations and (y) mail to each Holder a brief summary
of such certificate, indicating the locations at which CVRs may be presented for
payment and the date on which the payment referred to in Section 301(e) shall be
made.

         (g) The current market value per Share (the "Current Market Value")
shall be, during the 20 consecutive trading day period that both begins and ends
in the Valuation Period and which yields the highest such averages for any such
20 consecutive trading day period within the Valuation Period: (i) the mean of
the averages of the high and low and opening and closing prices, regular way, on
the New York Stock Exchange (or, if the Shares are not listed thereon, the
principal other exchange on which such shares are then listed); (ii) if the
Shares are not then listed or admitted to trading on any securities exchange,
the mean of the averages of the high and low and opening and closing sale price
on such days, or if no sale takes place on such days, the mean of the averages
of the high and low and opening and closing bid and asked prices on such days,
as reported by a reputable quotation source designated by the Company; or (iii)
if the Shares are not then listed or admitted to trade on any securities
exchange and no such reported sale price or bid and asked prices are available,
the mean of the averages of the reported high and low and opening and closing
bid and asked prices on those days on which such information is available, as
reported in the Authorized Newspaper. Notwithstanding the foregoing, in
computing Current Market Value for

                                       14
<PAGE>

purposes of an Early Redemption or the Automatic Extinguishment, no such 20
consecutive day period may be included in which the Company, any of its
subsidiaries or controlled Affiliates or Steven A. Markel, Anthony F. Markel or
Alan I. Kirshner purchase any Shares, except (x) in privately negotiated
transactions that are not reported to any exchange (other than as a result of
being disclosed in a filing with the Commission that is also required to be
filed with such exchange), (y) with respect to employee benefit plans and other
incentive compensation arrangements in the ordinary course of business and (z)
purchases in compliance with Rule 10b-18 promulgated under the Exchange Act.

         "Valuation Period" means (i) with respect to a payment at the Maturity
Date, the 60 day trading period immediately preceding (and including) the
Maturity Date, and (ii) with respect to an Automatic Extinguishment or an Early
Redemption, the period of time after the Effective Time and ending on the
Maturity Date.

         (h) In the event the Current Market Value or fair market value, as the
case may be, is determined by an Independent Financial Expert, the Company shall
cause the Independent Financial Expert to deliver to the Company, with a copy to
the Trustee, a value report (the "Value Report") stating the methods of
valuation considered or used and, if applicable, the per share value of the
Shares, and containing a statement as to the nature and scope of the examination
or investigation upon which the determination of value was made. The Trustee
shall make available a copy of the Value Report to each Holder who requests such
Value Report. The determination of the Independent Financial Expert as set forth
in the Value Report absent manifest error shall be final and binding on the
Company and the Holders.

         (i) Notwithstanding any provision of this Agreement or the CVR
Certificates to the contrary, other than in the case of interest on the Default
Amount, no interest shall accrue on any amounts payable on the CVRs to any
Holder.

         (j) In the event that the Company determines that no amount is payable
on the CVRs to the Holders on the Maturity Date, or the Disposition Payment
Date, as the case may be, as a result of an Automatic Extinguishment or
otherwise, the Company shall give to the Trustee and each Holder written notice
of such determination. Upon making such determination, absent manifest error,
the CVR Certificates shall terminate and become null and void and the Holders
thereof shall have no further rights with respect thereto. The failure to give
such notice or any defect therein shall not affect the validity of such
determination.

         (k) In the event the Company shall in any manner subdivide (by stock
split, stock dividend or otherwise) or combine (by reverse stock split or
otherwise) the number of outstanding Shares, the Company shall similarly
subdivide or combine the CVRs and shall appropriately adjust the Discounted
Target Price, the Target Price, the Early Redemption Price and the Minimum
Price. In the case of a Nondisposition Event, appropriate adjustments will be
made to the Target Price, the Minimum Price, the Discounted Target Price and the
Early Redemption Price. Whenever an adjustment is made as provided in this
Section 301(k), the Company shall (i) promptly prepare an Officers' Certificate
setting forth such adjustment and a brief statement of the facts accounting for
such adjustment, (ii) promptly file with the Trustee a copy of such certificate
and (iii) mail a brief summary thereof to each Holder. The Trustee shall be
fully protected in relying on any such Officers' Certificate and on any
adjustment therein contained. Such adjustment absent manifest error shall be
final and binding on the Company and the Holders. Each outstanding CVR
Certificate shall thenceforth represent that number of adjusted CVRs necessary
to reflect such subdivision or combination, and reflect the adjusted Discounted
Target Price, Target Price, the Early Redemption Price and the Minimum Price.

         (l) If the Current Market Value of the Shares during any 20 consecutive
trading days in the Valuation Period is greater than or equal to the Target
Price, the CVRs will automatically be extinguished without further consideration
or action by the Company, the Trustee or the Holders (the "Automatic
Extinguishment") and all obligations of the Company under this Agreement shall
terminate and be of no further force or effect; provided that the Company shall
(i) promptly prepare an Officers' Certificate certifying that an Automatic
Extinguishment has occurred and briefly stating the facts accounting for such

                                       15
<PAGE>

Automatic Extinguishment, (ii) promptly file with the Trustee a copy of such
certificate and (iii) mail a brief summary thereof to each Holder.

Section 302.  Registrable Form.

         The CVRs shall be issuable only in registered form.

Section 303.  Execution, Authentication, Delivery and Dating.

         The CVRs shall be executed on behalf of the Company by its chairman or
vice chairman of the Board of Directors or its president or any vice president
or its treasurer, under its corporate seal, which may, but need not, be
attested. The signature of any of these officers on the CVRs may be manual or
facsimile.

         CVRs bearing the manual or facsimile signatures of individuals who were
at any time the proper officers of the Company shall bind the Company,
notwithstanding that such individuals or any of them have ceased to hold such
offices prior to the authentication and delivery of such CVRs or did not hold
such offices at the date of such CVRs.

         At any time and from time to time after the execution and delivery of
this Agreement, the Company may deliver CVRs executed by the Company to the
Trustee for authentication, together with a Company Order for the authentication
and delivery of such CVRs; and the Trustee in accordance with such Company Order
shall authenticate and deliver such CVRs as provided in this Agreement and not
otherwise.

         Each CVR shall be dated as of the date of its authentication.

         No CVR shall be entitled to any benefit under this Agreement or be
valid or obligatory for any purpose unless there appears on such CVR a
certificate of authentication substantially in the form provided for herein duly
executed by the Trustee by manual signature of an authorized officer, and such
certificate upon any CVR shall be conclusive evidence, and the only evidence,
that such CVR has been duly authenticated and delivered hereunder and that the
Holder is entitled to the benefits of this Agreement.

Section 304.  Temporary CVRs.

         Pending the preparation of definitive CVRs, the Company may execute,
and upon Company Order the Trustee shall authenticate and deliver, temporary
CVRs which are printed, lithographed, typewritten, mimeographed or otherwise
produced, substantially of the tenor of the definitive CVRs in lieu of which
they are issued and with such appropriate insertions, omissions, substitutions
and other variations as the officers executing such CVRs may determine with the
concurrence of the Trustee. Temporary CVRs may contain such reference to any
provisions of this Agreement as may be appropriate. Every temporary CVR shall be
executed by the Company and be authenticated by the Trustee upon the same
conditions and in substantially the same manner, and with like effect, as the
definitive CVRs.

         If temporary CVRs are issued, the Company will cause definitive CVRs to
be prepared without unreasonable delay. After the preparation of definitive
CVRs, the temporary CVRs shall be exchangeable for definitive CVRs upon
surrender of the temporary CVRs at the office or agency of the Company
designated for such purpose pursuant to Section 702, without charge to the
Holder.

         Upon surrender for cancellation of any one or more temporary CVRs the
Company shall execute and the Trustee shall authenticate and deliver in exchange
therefor a like amount of definitive CVRs. Until so exchanged, the temporary
CVRs shall in all respects be entitled to the same benefits under this Agreement
as definitive CVRs.

Section 305.  Registration, Registration of Transfer and Exchange.

                                       16
<PAGE>

         The Company shall cause to be kept at the Corporate Trust Office of the
Trustee a register (the register maintained in such office and in any other
office or agency designated pursuant to Section 702 being herein sometimes
referred to as the "Security Register") in which, subject to such reasonable
regulations as it may prescribe, the Company shall provide for the registration
of CVRs and of transfers of CVRs. The Trustee is hereby initially appointed
"Security Registrar" for the purpose of registering CVRs and transfers of CVRs
as herein provided.

         Upon surrender for registration of transfer of any CVR at the office or
agency of the Security Registrar, the Company shall execute, and the Trustee
shall authenticate and deliver, in the name of the designated transferee or
transferees, one or more new CVR Certificates representing the same aggregate
number of CVRs represented by the CVR Certificate so surrendered that have been
transferred and the Company shall execute and the Trustee shall authenticate and
deliver, in the name of the transferor, one or more new CVR Certificates
represented by such CVR Certificate that are not to be transferred.

         At the option of the Holder, CVR Certificates may be exchanged for
other CVR Certificates that represent in the aggregate the same number of CVRs
as the CVR Certificates surrendered at such office or agency. Whenever any CVR
Certificates are so surrendered for exchange, the Company shall execute, and the
Trustee shall authenticate and deliver, the CVR Certificates that the Holder
making the exchange is entitled to receive.

         All CVRs issued upon any registration of transfer or exchange of CVRs
shall be the valid obligations of the Company, evidencing the same right, and
entitled to the same benefits under this Agreement, as the CVRs surrendered upon
such registration of transfer or exchange.

         Every CVR presented or surrendered for registration of transfer or for
exchange shall (if so required by the Company or the Security Registrar) be duly
endorsed, or be accompanied by a written instrument of transfer in form
satisfactory to the Company and the Security Registrar, duly executed by the
Holder thereof or his attorney duly authorized in writing.

         No service charge shall be made for any registration of transfer or
exchange of CVRs, but the Company may require payment of a sum sufficient to
cover any tax or other governmental charge that may be imposed in connection
with any registration of transfer or exchange of CVRs, other than exchanges
pursuant to Section 304 or not involving any transfer.

Section 306.  Mutilated, Destroyed, Lost and Stolen CVRs.

         If (a) any mutilated CVR is surrendered to the Trustee or (b) the
Company and the Trustee receive evidence to their satisfaction of the
destruction, loss or theft of any CVR, and there is delivered to the Company and
the Trustee such security or indemnity as may be required by them to save each
of them harmless, then, in the absence of notice to the Company or the Trustee
that such CVR has been acquired by a protected purchaser, the Company shall
execute and upon a Company Request the Trustee shall authenticate and deliver,
in exchange for any such mutilated CVR or in lieu of any such destroyed, lost or
stolen CVR, a new CVR Certificate of like tenor and amount of CVRs, bearing a
number not contemporaneously outstanding.

         In case any such mutilated, destroyed, lost or stolen CVR has become or
is to become due and payable within 15 days, the Company in its discretion may,
instead of issuing a new CVR Certificate, pay such CVR on the Maturity Date, the
Early Redemption Payment Date, the Disposition Payment Date or the Default
Payment Date, as the case may be.

         Upon the issuance of any new CVRs under this Section, the Company may
require the payment of a sum sufficient to cover any tax or other governmental
charge that may be imposed in relation thereto and any other expenses (including
the fees and expenses of the Trustee) connected therewith.

         Every new CVR issued pursuant to this Section in lieu of any destroyed,
lost

                                       17
<PAGE>

or stolen CVR shall constitute an original additional contractual obligation of
the Company, whether or not the destroyed, lost or stolen CVR shall be at any
time enforceable by anyone, and shall be entitled to all benefits of this
Agreement equally and proportionately with any and all other CVRs duly issued
hereunder.

         The provisions of this Section are exclusive and shall preclude (to the
extent lawful) all other rights and remedies with respect to the replacement or
payment of mutilated, destroyed, lost or stolen CVRs.

Section 307.  Presentation of CVR Certificate.

         Payment of any amounts on the CVRs shall be made only upon presentation
by the Holder thereof at the office or agency of the Company maintained for that
purpose in the Borough of Manhattan in the City of New York and at any other
office or agency maintained by the Company for such purpose. Such payment shall
be made, either, in the Company's sole discretion, (i) in Cash or (ii) in Stock.
The Holder of the CVRs shall furnish to the Company such forms, certificates, or
other information as the Company may request to establish the legal entitlement
of such Holder to an exemption from withholding taxes. In the event the Company
does not receive such forms, certificates or other evidence establishing a
Holder's legal entitlement to exemption from withholding tax, then all payments
and disbursements to be made by the Company pursuant to this Agreement or the
CVRs shall be reduced by and subject to withholding taxes. The Company shall
have no obligation to reimburse, equalize or compensate a Holder or other Person
for withholding taxes.

Section 308.  Persons Deemed Owners.

         Prior to the time of due presentment for registration of transfer, the
Company, the Trustee and any agent of the Company or the Trustee may treat the
Person in whose name any CVR is registered as the owner of such CVR for the
purpose of receiving payment on such CVR and for all other purposes whatsoever,
whether or not such CVR be overdue, and neither the Company, the Trustee nor any
agent of the Company or the Trustee shall be affected by notice to the contrary.

Section 309.  Cancellation.

         All CVRs surrendered for payment, registration of transfer or exchange
shall, if surrendered to any Person other than the Trustee, be delivered to the
Trustee and shall be promptly cancelled by it. The Company may at any time
deliver to the Trustee for cancellation any CVRs previously authenticated and
delivered hereunder which the Company may have acquired in any manner
whatsoever, and all CVRs so delivered shall be promptly cancelled by the
Trustee. No CVRs shall be authenticated in lieu of or in exchange for any CVRs
cancelled as provided in this Section, except as expressly permitted by this
Agreement. All cancelled CVRs held by the Trustee shall be disposed of by the
Trustee in accordance with its customary procedures unless otherwise directed by
a Company Order.

                                 ARTICLE FOUR

                                  THE TRUSTEE

Section 401.  Certain Duties and Responsibilities.

         (a) With respect to the Holders of CVRs issued hereunder, the Trustee,
prior to the occurrence of an Event of Default with respect to the CVRs and
after the curing or waiving of all Events of Default which may have occurred,
undertakes to perform such duties and only such duties as are specifically set
forth in this Agreement. In case an Event of Default with respect to the CVRs
has occurred (which has not been cured or waived), the Trustee shall exercise
such of the rights and powers vested in it by this Agreement, and use the same
degree of care and skill in their exercise, as a prudent man would exercise or
use under the circumstances in the conduct of his own affairs.

                                       18
<PAGE>

         (b) In the absence of bad faith on its part, prior to the occurrence of
an Event of Default and after the curing or waiving of all such Events of
Default which may have occurred, the Trustee may conclusively rely, as to the
truth of the statements and the correctness of the opinions expressed therein,
upon certificates or opinions furnished to the Trustee and conforming to the
requirements of this Agreement; but in the case of any such certificates or
opinions which by any provision hereof are specifically required to be furnished
to the Trustee, the Trustee shall be under a duty to examine the same to
determine whether or not they conform to the requirements of this Agreement.

         (c) No provision of this Agreement shall be construed to relieve the
Trustee from liability for its own negligent action, its own negligent failure
to act, or its own willful misconduct, except that

                  (1) this Subsection (c) shall not be construed to limit the
         effect of Subsections (a) and (b) of this Section;

                  (2) the Trustee shall not be liable for any error of judgment
         made in good faith by a Responsible Officer, unless it shall be proved
         that the Trustee was negligent in ascertaining the pertinent facts;

                  (3) no provision of this Agreement shall require the Trustee
         to expend or risk its own funds or otherwise incur any financial
         liability in the performance of any of its duties hereunder, or in the
         exercise of any of its rights or powers, if it shall have reasonable
         grounds for believing that repayment of such funds or adequate
         indemnity against such risk or liability is not reasonably assured to
         it; and

                  (4) the Trustee shall not be liable with respect to any action
         taken or omitted to be taken by it in good faith in accordance with the
         direction of the Holders pursuant to Section 809 relating to the time,
         method and place of conducting any proceeding for any remedy available
         to the Trustee, or exercising any trust or power conferred upon the
         Trustee, under this Agreement.

         (d) Whether or not therein expressly so provided, every provision of
this Agreement relating to the conduct or affecting the liability of or
affording protection to the Trustee shall be subject to the provisions of this
Section.

Section 402. Certain Rights of Trustee.

         The Trustee undertakes to perform such duties and only such duties as
are specifically set forth in this Agreement, and no implied covenants or
obligations shall be read into this Agreement against the Trustee. Subject to
the provisions of Trust Indenture Act Sections 315(a) through 315(d) and Section
401 hereof:

                  (a) the Trustee may rely and shall be protected in acting or
         refraining from acting upon any resolution, certificate, statement,
         instrument, opinion, report, notice, request, direction, consent,
         order, bond, debenture, note, other evidence of indebtedness or other
         paper or document believed by it to be genuine and to have been signed
         or presented by the proper party or parties;

                  (b) any request or direction of the Company mentioned herein
         shall be sufficiently evidenced by a Company Request or Company Order
         and any resolution of the Board of Directors may be sufficiently
         evidenced by a Board Resolution;

                  (c) whenever in the administration of this Agreement the
         Trustee shall deem it desirable that a matter be proved or established
         prior to taking, suffering or omitting any action hereunder, the
         Trustee (unless other evidence be herein specifically prescribed) may,
         in the absence of bad faith on its part, rely upon an Officer's
         Certificate;

                                       19
<PAGE>

                  (d) the Trustee may consult with counsel and the written
         advice of such counsel or any Opinion of Counsel shall be full and
         complete authorization and protection in respect of any action taken,
         suffered or omitted by it hereunder in good faith and in reliance
         thereon;

                  (e) the Trustee shall be under no obligation to exercise any
         of the rights or powers vested in it by this Agreement at the request
         or direction of any of the Holders pursuant to this Agreement, unless
         such Holders shall have offered to the Trustee reasonable security or
         indemnity against the costs, expenses and liabilities which might be
         incurred by it in compliance with such request or direction;

                  (f) the Trustee shall not be bound to make any investigation
         into the facts or matters stated in any resolution, certificate,
         statement, instrument, opinion, report, notice, request, consent,
         order, approval, appraisal, bond, debenture, note, coupon, security, or
         other paper or document unless requested in writing to do so by the
         Holders of not less than a majority in aggregate number of the CVRs
         then Outstanding; provided that, if the payment within a reasonable
         time to the Trustee of the costs, expenses or liabilities likely to be
         incurred by it in the making of such investigation is, in the opinion
         of the Trustee, not reasonably assured to the Trustee by the security
         afforded to it by the terms of this Agreement, the Trustee may require
         reasonable indemnity against such expenses or liabilities as a
         condition to proceeding; the reasonable expenses of every such
         investigation shall be paid by the Company or, if paid by the Trustee
         or any predecessor Trustee, shall be repaid by the Company upon demand;

                  (g) the Trustee may execute any of the trusts or powers
         hereunder or perform any duties hereunder either directly or by or
         through agents or attorneys and the Trustee shall not be responsible
         for any misconduct or negligence on the part of any agent or attorney
         appointed with due care by it hereunder;

                  (h) the permissive rights of the Trustee to do things
         enumerated in this Indenture shall not be construed as a duty and the
         Trustee shall be liable for its negligence, bad faith or willful
         misconduct; and

                  (i) the Trustee shall not be charged with knowledge of any
         Event of Default with respect to the CVRs unless either (1) a
         Responsible Officer of the Trustee shall have actual knowledge of the
         Event of Default or (2) written notice of such Event of Default shall
         have been given to the Trustee by the Company, any other obligor on
         such CVRs or by any Holder of such CVRs.

         No provision of this Agreement shall require the Trustee to expend or
risk its own funds or otherwise incur any financial liability in the performance
of any of its duties hereunder, or in the exercise of any of its rights or
powers, if it shall have reasonable grounds for believing that repayment of such
funds or adequate indemnity against such risk or liability is not reasonably
assured to it.

Section 403.  Not Responsible for Recitals or Issuance of CVRs.

         The recitals contained herein and in the CVRs, except the Trustee's
certificates of authentication, 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 Agreement or
of the CVRs. The Trustee shall not be accountable for the use or application by
the Company of CVRs or the proceeds thereof.

Section 404.  May Hold CVRs.

         The Trustee, any Paying Agent, Security Registrar or any other agent of
the Company, in its individual or any other capacity, may become the owner or
pledgee of CVRs, and, subject to Sections 407 and 401, may otherwise deal with
the Company with the same rights it would have if it were not Trustee, Paying
Agent, Security Registrar or such other agent.

                                       20
<PAGE>

Section 405.  Money Held in Trust.

         Money held by the Trustee in trust hereunder need not be segregated
from other funds except to the extent required by law. The Trustee shall be
under no liability for interest on any money received by it hereunder.

Section 406.  Compensation, Reimbursement and Indemnification of the Trustee.

         The Company agrees

                  (a) to pay to the Trustee from time to time reasonable
         compensation for all services rendered by it hereunder (which
         compensation shall not be limited by any provision of law in regard to
         the compensation of a trustee of an express trust);

                  (b) except as otherwise expressly provided herein, to
         reimburse the Trustee upon its request for all reasonable expenses,
         disbursements and advances incurred or made by the Trustee in
         accordance with any provision of this Agreement (including the
         reasonable compensation and the expenses and disbursements of its
         agents and counsel), except any such expense, disbursement or advance
         as may be attributable to its negligence or bad faith; and

                  (c) to indemnify the Trustee for, and to hold it harmless
         against, any loss, liability or expense incurred without negligence or
         bad faith on its part, arising out of or in connection with the
         acceptance or administration of this trust, including the costs and
         expenses of defending itself against any claim or liability in
         connection with the exercise or performance of any of its powers or
         duties hereunder, including the enforcement of this Section 406.

         When the Trustee incurs expenses or renders services after an Event of
Default specified in Section 801(c) or 801(d) occurs, the reasonable expenses
and the compensation for services (including the reasonable fees and expenses of
its agents and counsel) are intended to constitute expenses of administration
under any bankruptcy law.

         The obligations of the Company under this Section 406 shall survive the
resignation or removal of the Trustee and the satisfaction and discharge of this
Agreement.

Section 407.  Disqualification; Conflicting Interests.

         The Trustee shall be subject to the provisions of Section 310(b) of the
Trust Indenture Act during the period of time provided for therein. Nothing
herein shall prevent the Trustee from filing with the Commission the application
referred to in the penultimate paragraph of Section 310(b) of the Trust
Indenture Act.

Section 408.  Corporate Trustee Required; Eligibility.

         There shall at all times be a Trustee hereunder which shall be a
corporation organized and doing business under the laws of the United States of
America or of any State, authorized under such laws to exercise corporate trust
powers, having a combined capital and surplus of at least $50,000,000, subject
to supervision or examination by Federal or State authority and, to the extent
there is such an institution eligible and willing to serve, having an office or
agency in the City of New York, the City of Richmond, Virginia or the City of
Charlotte, North Carolina. If such corporation publishes reports of condition at
least annually pursuant to law or to the requirements of the aforesaid
supervising or examining authority, then, for the purposes of this Section, the
combined capital and surplus of such corporation shall be deemed to be its
combined capital and surplus as set forth in its most recent report of condition
so published. If at any time the Trustee shall cease to be eligible in
accordance with the provisions of this Section, it shall resign immediately in
the manner and with the effect hereinafter specified in this Article.

Section 409.  Resignation and Removal; Appointment of Successor.

                                       21
<PAGE>

         (a) No resignation or removal of the Trustee and no appointment of a
successor Trustee pursuant to this Article shall become effective until the
acceptance of appointment by the successor Trustee under Section 410.

         (b) The Trustee, or any trustee or trustees hereafter appointed, may
resign at any time by giving written notice thereof to the Company. If an
instrument of acceptance by a successor Trustee shall not have been delivered to
the Trustee within 30 days after the giving of such notice of resignation, the
resigning Trustee may petition any court of competent jurisdiction for the
appointment of a successor Trustee.

         (c) The Trustee may be removed at any time by (i) the Company, by a
Board Resolution, unless an Event of Default has occurred and is continuing or,
(ii) an Act of the Holders of a majority of the Outstanding CVRs, delivered to
the Trustee and to the Company.

         (d)  If at any time:

                  (1) the Trustee shall fail to comply with Section 407 after
         written request therefor by the Company or by any Holder who has been a
         bona fide Holder of a CVR for at least six months,

                  (2) the Trustee shall cease to be eligible under Section 408
         and shall fail to resign after written request therefor by the Company
         or by any such Holder, or

                  (3) the Trustee shall become incapable of acting or shall be
         adjudged bankrupt or insolvent, or a receiver of the Trustee or of its
         property shall be appointed, or any public officer shall take charge or
         control of the Trustee or of its property or affairs for the purpose of
         rehabilitation, conservation or liquidation, then, in any case, (i) the
         Company by a Board Resolution may remove the Trustee, or (ii) the
         Holder of any CVR who has been a bona fide Holder of a CVR for at least
         six months may, on behalf of himself and all others similarly situated,
         petition any court of competent jurisdiction for the removal of the
         Trustee and the appointment of a successor Trustee.

         (e) If the Trustee shall resign, be removed or become incapable of
acting, or if a vacancy shall occur in the office of Trustee for any reason, the
Company, by a Board Resolution, shall promptly appoint a successor Trustee. If,
within one year after such resignation, removal or incapability, or the
occurrence of such vacancy, a successor Trustee shall be appointed by Act of the
Holders of a majority of the Outstanding CVRs delivered to the Company and the
retiring Trustee, the successor Trustee so appointed shall, forthwith upon its
acceptance of such appointment in accordance with Section 410, become the
successor Trustee and supersede the successor Trustee appointed by the Company.
If no successor Trustee shall have been so appointed by the Company or the
Holders of the CVRs and so accepted appointment, the Holder of any CVR who has
been a bona fide Holder for at least six months may on behalf of himself and all
others similarly situated, petition any court of competent jurisdiction for the
appointment of a successor Trustee.

         (f) The Company shall give notice of each resignation and each removal
of the Trustee and each appointment of a successor Trustee by mailing written
notice of such event by first-class mail, postage prepaid, to the Holders of
CVRs as their names and addresses appear in the Security Register. Each notice
shall include the name of the successor Trustee and the address of its Corporate
Trust Office. If the Company fails to send such notice within ten days after
acceptance of appointment by a successor Trustee, the successor Trustee shall
cause the notice to be mailed at the expense of the Company.

Section 410.  Acceptance of Appointment by Successor.

         Every successor Trustee appointed hereunder shall execute, acknowledge
and deliver to the Company and to the retiring Trustee an instrument accepting
such appointment, and thereupon the resignation or removal of the retiring
Trustee shall become effective and such successor Trustee, without any further
act, deed or conveyance, shall become vested with all the rights, powers, trusts
and duties of the retiring Trustee; but, on request of the Company or the
successor Trustee, such retiring Trustee shall, upon

                                       22
<PAGE>

payment of its charges, execute and deliver an instrument transferring to such
successor Trustee all the rights, powers and trusts of the retiring Trustee, and
shall duly assign, transfer and deliver to such successor Trustee all property
and money held by such retiring Trustee hereunder. Upon request of any such
successor Trustee, the Company shall execute any and all instruments for more
fully and certainly vesting in and confirming to such successor Trustee all such
rights, powers and trusts.

         No successor Trustee shall accept its appointment unless at the time of
such acceptance such successor Trustee shall be qualified and eligible under
this Article.

Section 411.  Merger, Conversion, Consolidation or Succession to Business.

         Any corporation into which the Trustee may be merged or converted or
with which it may be consolidated, or any corporation resulting from any merger,
conversion or consolidation to which the Trustee shall be a party, or any
corporation succeeding to all or substantially all of the corporate trust
business of the Trustee, shall be the successor of the Trustee hereunder,
provided such corporation shall be otherwise qualified and eligible under this
Article, without the execution or filing of any paper or any further act on the
part of any of the parties hereto. In case any CVRs shall have been
authenticated, but not delivered, by the Trustee then in office, any successor
by merger, conversion or consolidation to such authenticating Trustee may adopt
such authentication and deliver the CVRs so authenticated with the same effect
as if such successor Trustee had itself authenticated such CVRs; and such
certificate shall be fully effective, provided that the right to adopt the
certificate of authentication of any predecessor Trustee shall apply only to its
successor or successors by merger, conversion or consolidation.

                                 ARTICLE FIVE

               HOLDERS' LISTS AND REPORTS BY TRUSTEE AND COMPANY

Section 501.  Company to Furnish Trustee Names and Addresses of Holders.

         The Company will furnish or cause to be furnished to the Trustee at
such times as the Trustee may request in writing, within 30 days after receipt
by the Company of any such request, a list, in such form as the Trustee may
reasonably require, of the names and the addresses of the Holders as of a date
not more than 15 days prior to the time such list is furnished; provided,
however, that, if and so long as the Trustee shall be the Security Registrar, no
such list need be furnished.

Section 502.  Preservation of Information; Communications to Holders.

         (a) The Trustee shall preserve, in as current a form as is reasonably
practicable, the names and addresses of Holders contained in the most recent
list furnished to the Trustee as provided in Section 501 and the names and
addresses of Holders received by the Trustee in its capacity as Security
Registrar. The Trustee may destroy any list furnished to it as provided in
Section 501 upon receipt of a new list so furnished.

         (b) If three or more Holders (hereinafter referred to as "applicants")
apply in writing to the Trustee, and furnish to the Trustee reasonable proof
that each such applicant has owned a CVR for a period of at least six months
preceding the date of such application, and such application states that the
applicants desire to communicate with other Holders with respect to their rights
under this Agreement or under the CVRs and is accompanied by a copy of the form
of proxy or other communication which such applicants propose to transmit, then
the Trustee shall, within five Business Days after the receipt of such
application at its election, either

                  (1)  afford such applicants access to the information
         preserved at the time by the Trustee in accordance with Section 502(a),
         or

                                       23
<PAGE>

                  (2) inform such applicants as to the approximate number of
         Holders whose names and addresses appear in the information preserved
         at the time by the Trustee in accordance with Section 502(a), and as to
         the approximate cost of mailing to such Holders the form of proxy or
         other communication, if any, specified in such application.

         If the Trustee shall elect not to afford such applicants access to such
information, the Trustee shall, upon the written request of such applicants,
mail to each Holder whose name and address appear in the information preserved
at the time by the Trustee in accordance with Section 502(a), a copy of the form
of proxy or other communication which is specified in such request, with
reasonable promptness after a tender to the Trustee of the material to be mailed
and of payment, or provision for the payment, of the reasonable expenses of
mailing, unless within five days after such tender, the Trustee shall mail to
such applicants and file with the Commission, together with a copy of the
material to be mailed, a written statement to the effect that, in the opinion of
the Trustee, such mailing would be contrary to the best interests of the Holders
or would be in violation of applicable law. Such written statement shall specify
the basis of such opinion. If the Commission, after opportunity for a hearing
upon the objections specified in the written statement so filed, shall enter an
order refusing to sustain any of such objections or if, after the entry of an
order sustaining one or more of such objections, the Commission shall find,
after notice and opportunity for hearing, that all the objections so sustained
have been met and shall enter an order so declaring, the Trustee shall mail
copies of such material to all such Holders with reasonable promptness after the
entry of such order and the renewal of such tender; otherwise the Trustee shall
be relieved of any obligation or duty to such applicants respecting their
application.

         (c) Every Holder of CVRs, by receiving and holding the same, agrees
with the Company and the Trustee that neither the Company nor the Trustee shall
be held accountable by reason of the disclosure of any such information as to
the names and addresses of the Holders in accordance with Section 502(b),
regardless of the source from which such information was derived, and that the
Trustee shall not be held accountable by reason of mailing any material pursuant
to a request made under Section 502(b).

Section 503.  Reports by Trustee.

         Within 60 days after May 15 of each year, commencing with the May 15
occurring after the initial issuance of CVRs hereunder, the Trustee shall
transmit by mail to the Holders of CVRs, in the manner and to the extent
provided in Section 313(c) of the Trust Indenture Act, and to the Company a
brief report dated as of such May 15 which satisfies the requirements of Section
313(a) of the Trust Indenture Act.

Section 504.  Reports by Company.

         The Company shall:

                  (a) file with the Trustee, within 15 days after the date on
         which the Company is required to file the same with the Commission,
         copies of the annual reports and of the information, documents and
         other reports (or copies of such portions of any of the foregoing as
         the Commission may from time to time by rules and regulations
         prescribe) which the Company may be required to file with the
         Commission pursuant to Section 13 or Section 15(d) of the Exchange Act;
         or, if the Company is not required to file information, documents or
         reports pursuant to either of such sections, then to file with the
         Trustee and the Commission, in accordance with rules and regulations
         prescribed from time to time by the Commission, such of the
         supplementary and periodic information, documents and reports which may
         be required pursuant to Section 13 of the Exchange Act in respect of a
         security listed and registered on a national securities exchange as may
         be prescribed from time to time in such rules and regulations; and

                  (b) file with the Trustee and the Commission, in accordance
         with the rules and regulations prescribed from time to time by the
         Commission, such additional information, documents and reports with
         respect to compliance by the Company with the conditions and covenants
         of this Agreement as may be required from time to time by such rules
         and regulations.



                                       24
<PAGE>

         The Company shall transmit by mail to all Holders, as their names and
addresses appear in the Security Register, within 30 days after the filing
thereof with the Trustee, such summaries of any information, documents and
reports required to be filed by the Company pursuant to Subsections (a) and (b)
of this Section as may be required by rules and regulations prescribed from time
to time by the Commission.

                                  ARTICLE SIX

                                  AMENDMENTS

Section 601.  Amendments Without Consent of Holders.

         Without the consent of any Holders, the Company, when authorized by a
Board Resolution, and the Trustee, at any time and from time to time, may enter
into one or more amendments hereto, in form satisfactory to the Trustee, for any
of the following purposes:

                  (a)  to convey, transfer, assign, mortgage or pledge to the
         Trustee as security for the CVRs any property or assets;

                  (b)  to evidence the succession of another Person to the
         Company, and the assumption by any such successor of the covenants of
         the Company herein and in the CVRs;

                  (c) to add to the covenants of the Company such further
         covenants, restrictions, conditions or provisions as its Board of
         Directors shall consider to be for the protection of the Holders of
         CVRs, and to make the occurrence, or the occurrence and continuance, of
         a default in any such additional covenants, restrictions, conditions or
         provisions an Event of Default permitting the enforcement of all or any
         of the several remedies provided in this Agreement as herein set forth;
         provided that in respect of any such additional covenant, restriction,
         condition or provision such amendment may provide for a particular
         period of grace after default (which period may be shorter or longer
         than that allowed in the case of other defaults) or may provide for an
         immediate enforcement upon such an Event of Default or may limit the
         remedies available to the Trustee upon such an Event of Default or may
         limit the right of the Holders of a majority in aggregate principal
         amount of the CVRs to waive such an Event of Default; or

                  (d) to cure any ambiguity, to correct or supplement any
         provision herein which may be defective or inconsistent with any other
         provision herein, or to make any other provisions with respect to
         matters or questions arising under this Agreement; provided that in
         each case, such provisions shall not adversely affect the interests of
         the Holders.

Section 602.  Amendments with Consent of Holders.

         With the consent of the Holders of not less than a majority of the
Outstanding CVRs as required to amend the Agreement in accordance with the Trust
Indenture Act, by Act of said Holders delivered to the Company and the Trustee,
the Company, when authorized by a Board Resolution, and the Trustee may enter
into one or more amendments hereto for the purpose of adding any provisions to
or changing in any manner or eliminating any of the provisions of this Agreement
or of modifying in any manner the rights of the Holders under this Agreement;
provided that no such amendment shall, without the consent of the Holder of each
Outstanding CVR affected thereby:

                  (a) modify the definition of Maturity Date, Disposition
         Payment Date, Default Payment Date, Early Redemption Payment, Early
         Redemption Determination Date, Current Market Value, Valuation Period,
         Minimum Price, Discounted Target Price, Target Price, Default Amount or
         Default Interest Rate or modify Section 301(k) or otherwise extend the
         maturity of the CVRs or reduce the amounts payable in respect of the
         CVRs;

                                       25
<PAGE>

                  (b)  reduce the amount of the Outstanding CVRs, the consent of
         whose Holders is required for any such amendment; or

                  (c)  modify any of the provisions of this Section, except to
         increase any such percentage or to provide that certain other
         provisions of this Agreement cannot be modified or waived without the
         consent of the Holder of each CVR affected thereby.

         It shall not be necessary for any Act of Holders under this Section to
approve the particular form of any proposed amendment, but it shall be
sufficient if such Act shall approve the substance thereof.

         Promptly after the execution by the Company and the Trustee of any
amendment pursuant to the provisions of this Section, the Company shall mail a
notice thereof by first class mail to the Holders of CVRs at their addresses as
they shall appear on the Security Register, setting forth in general terms the
substance of such amendment. Any failure of the Company to mail such notice, or
any defect therein, shall not, however, in any way impair or affect the validity
of any such amendment.

Section 603.  Execution of Amendments.

         In executing any amendment permitted by this Article, the Trustee shall
be entitled to receive, and (subject to Section 401) shall be fully protected in
relying upon, in addition to the documents required by Section 102, an Opinion
of Counsel stating that the execution of such amendment is authorized or
permitted by this Agreement. The Trustee may, but shall not be obligated to,
enter into any such amendment which affects the Trustee's own rights, duties or
immunities under this Agreement or otherwise.

Section 604.  Effect of Amendments.

         Upon the execution of any amendment under this Article, this Agreement
shall be modified in accordance therewith, and such amendment shall form a part
of this Agreement for all purposes; and every Holder of CVRs theretofore or
thereafter authenticated and delivered hereunder shall be bound thereby.

Section 605.  Conformity with Trust Indenture Act.

         Every amendment executed pursuant to this Article shall conform to the
requirements of the Trust Indenture Act as then in effect.

Section 606.  Reference in CVRs to Amendments.

         CVRs authenticated and delivered after the execution of any amendment
pursuant to this Article may, and shall if required by the Trustee, bear a
notation in form approved by the Trustee as to any matter provided for in such
amendment. If the Company shall so determine, new CVRs so modified as to
conform, in the opinion of the Trustee and the Board of Directors, to any such
amendment may be prepared and executed by the Company and authenticated and
delivered by the Trustee in exchange for Outstanding CVRs.


                                  ARTICLE SEVEN

                                    COVENANTS

Section 701.  Payment of Amounts, if Any, to Holders.

         The Company will duly and punctually pay the amounts, if any, in the
manner provided for in Section 307 on the CVRs in accordance with the terms of
the CVRs and this Agreement.

Section 702.  Maintenance of Office or Agency.

                                       26
<PAGE>

         As long as any of the CVRs remain Outstanding, the Company will
maintain in the Borough of Manhattan, the City of New York, an office or agency
where CVRs may be presented or surrendered for payment. The Company also will
maintain in the Borough of Manhattan, the City of New York, the City of
Richmond, Virginia, or the City of Charlotte, North Carolina, an office or
agency (i) where CVRs may be surrendered for registration of transfer or
exchange and (ii) where notices and demands to or upon the Company in respect of
the CVRs and this Agreement may be served. The Company hereby initially
designates the Corporate Trust Office of the Trustee as the office or agency of
the Company where CVRs may be presented for payment, and the office or agency
where CVRs may be surrendered for registration of transfer or exchange and where
such notices or demands may be served, in each case, unless the Company shall
designate and maintain some other office or agency for one or more of such
purposes. The Company will give prompt written notice to the Trustee of any
change in the location of any such office or agency. If at any time the Company
shall fail to maintain any such required office or agency or shall fail to
furnish the Trustee with the address thereof, such presentations, surrenders,
notices and demands may be made or served at the Corporate Trust Office of the
Trustee, and the Company hereby appoints the Trustee as its agent to receive all
such presentations, surrenders, notices and demands.

         The Company may from time to time designate one or more other offices
or agencies (in or outside of the City of New York) where the CVRs may be
presented or surrendered for any or all such purposes, and may from time to time
rescind such designation; provided, however, that no such designation or
rescission shall in any manner relieve the Company of its obligations as set
forth in the preceding paragraph. The Company will give prompt written notice to
the Trustee of any such designation or rescission and any change in the location
of any such office or agency.

Section 703.  Money for CVR Payments to Be Held in Trust.

         If the Company shall at any time act as its own Paying Agent, it will,
on or before the Maturity Date, the Early Redemption Payment Date, the
Disposition Payment Date or the Default Payment Date, as the case may be,
segregate and hold in trust for the benefit of the Persons entitled thereto a
sum sufficient to pay the amounts, if any, so becoming due until such sums shall
be paid to such Persons or otherwise disposed of as herein provided, and will
promptly notify the Trustee of its action or failure so to act.

         Whenever the Company shall have one or more Paying Agents for the CVRs,
it will, on or before the Maturity Date, the Early Redemption Payment Date, the
Disposition Payment Date or the Default Payment Date, as the case may be,
deposit with a Paying Agent a sum in same day funds sufficient to pay the
amount, if any, so becoming due, such sum to be held in trust for the benefit of
the Persons entitled to such amount, and (unless such Paying Agent is the
Trustee) the Company will promptly notify the Trustee of such action or any
failure so to act.

         The Company will cause each Paying Agent other than the Trustee to
execute and deliver to the Trustee an instrument in which such Paying Agent
shall agree with the Trustee, subject to the provisions of this Section, that
(A) such Paying Agent will hold all sums held by it for the payment of any
amount payable on CVRs in trust for the benefit of the Persons entitled thereto
until such sums shall be paid to such Persons or otherwise disposed of as herein
provided and (B) that it will give the Trustee notice of any failure by the
Company (or by any other obligor on the CVRs) to make any payment on the CVRs
when the same shall be due and payable.

         Any money (or securities of the Company) deposited with the Trustee or
any Paying Agent, or then held by the Company, in trust for the payment on any
CVRs and remaining unclaimed for one year after the Maturity Date, the Early
Redemption Payment Date, the Disposition Payment Date or the Default Payment
Date, as the case may be, shall be paid to the Company on Company Request, or
(if then held by the Company) shall be discharged from such trust; and the
Holder of such CVR shall thereafter, as an unsecured general creditor, look only
to the Company for payment thereof and all liability of the Trustee or such
Paying Agent with respect to such trust money (or securities of the Company)
shall thereupon cease.

Section 704.  Certain Purchases and Sales.

                                       27
<PAGE>

         The Company will not, and will not permit any of its subsidiaries or
controlled Affiliates or Steven A. Markel, Anthony F. Markel or Alan I.
Kirshner, to purchase any Shares on any day during the period commencing 10
trading days before the Valuation Period with respect to the Maturity Date and
ending on the Maturity Date, except (x) in privately negotiated transactions
that are not reported to any exchange (other than as a result of being disclosed
in a filing with the Commission that is also required to be filed with such
exchange), (y) with respect to employee benefit plans and other incentive
compensation arrangements in the ordinary course of business and (z) purchases
in compliance with Rule 10b-18 promulgated under the Exchange Act.

Section 705.  Written Statement to Trustee.

         The Company will deliver to the Trustee, within 120 days after the end
of each fiscal year, a brief certificate from the principal executive officer,
principal financial officer or principal accounting officer as to his or her
knowledge of the Company's compliance with all conditions and covenants under
this Agreement. For purposes of this Section, such compliance shall be
determined without regard to any period of grace or requirement of notice under
this Agreement.

                                 ARTICLE EIGHT

            REMEDIES OF THE TRUSTEE AND HOLDERS ON EVENT OF DEFAULT

Section 801. Event of Default Defined; Acceleration of Maturity; Waiver of
             Default.

         "Event of Default", with respect to CVRs, means any of the following
events which shall have occurred and be continuing (whatever the reason for such
Event of Default and whether it shall be voluntary or involuntary or be effected
by operation of law or pursuant to any judgment, decree or order of any court or
any order, rule or regulation of any administrative or governmental body):

                  (a) default in the payment of all or any part of the amounts
         payable in respect of any of the CVRs as and when the same shall become
         due and payable following the Maturity Date, the Disposition Payment
         Date, the Early Redemption Payment Date or otherwise;

                  (b) default in the performance, or breach, of any covenant or
         warranty of the Company relating to the CVRs (other than a covenant or
         warranty in respect of the CVRs a default in whose performance or whose
         breach is elsewhere in this Section specifically dealt with), and
         continuance of such default or breach for a period of 90 days after
         there has been given, by registered or certified mail, to the Company
         by the Trustee or to the Company and the Trustee by the Holders of at
         least 25% of the Outstanding CVRs, a written notice specifying such
         default or breach and requiring it to be remedied and stating that such
         notice is a "Notice of Default" hereunder;

                  (c) a court having jurisdiction in the premises shall enter a
         decree or order for relief in respect of the Company in an involuntary
         case under any applicable bankruptcy, insolvency or other similar law
         now or hereafter in effect, or appointing a receiver, liquidator,
         assignee, custodian, trustee or sequestrator (or similar official) of
         the Company or for any substantial part of its property or ordering the
         winding up or liquidation of its affairs, and such decree or order
         shall remain unstayed and in effect for a period of 60 consecutive
         days; or

                  (d) the Company shall commence a voluntary case under any
         applicable bankruptcy, insolvency or other similar law now or hereafter
         in effect, or consent to the entry of an order for relief in an
         involuntary case under any such law, or consent to the appointment of
         or taking possession by a receiver, liquidator, assignee, custodian,
         trustee or sequestrator (or similar official) of the Company or for any
         substantial part of its property, or make any general assignment for
         the benefit of creditors.

                                       28
<PAGE>

If an Event of Default described above occurs and is continuing, then, and in
each and every such case, unless all of the CVRs shall have already become due
and payable, either the Trustee or the Holders of not less than 25% of the CVRs
then Outstanding hereunder by notice in writing to the Company (and to the
Trustee if given by the Holders) may declare the CVRs to be due and payable
immediately, and upon any such declaration the Default Amount shall become
immediately due and payable and, thereafter, shall bear interest at the Default
Interest Rate until payment is made to the Trustee.

         The foregoing provisions, however, are subject to the condition that
if, at any time after the CVRs shall have been so declared due and payable, and
before any judgment or decree for the payment of the moneys due shall have been
obtained or entered as hereinafter provided, the Company shall pay or shall
deposit with the Trustee a sum sufficient to pay all amounts which shall have
become due otherwise than by acceleration (with interest upon such overdue
amount at the Default Interest Rate to the date of such payment or deposit) and
such amount as shall be sufficient to cover reasonable compensation to the
Trustee, its agents, attorneys and counsel, and all other amounts due the
Trustee under Section 406, and if any and all Events of Default under this
Agreement, other than the nonpayment of the amounts which shall have become due
by acceleration, shall have been cured, waived or otherwise remedied as provided
herein, then and in every such case the Holders of a majority of all the CVRs
then Outstanding, by written notice to the Company and to the Trustee, may waive
all defaults with respect to the CVRs and rescind and annul such declaration and
its consequences, but no such waiver or rescission and annulment shall extend to
or shall affect any subsequent default or shall impair any right consequent
thereof.

Section 802.  Collection of Indebtedness by Trustee; Trustee May Prove Debt.

         The Company covenants that in case default shall be made in the payment
of all or any part of the CVRs when the same shall have become due and payable;
whether at the Maturity Date, the Early Redemption Payment Date, the Disposition
Payment Date, the Default Payment Date or otherwise, then upon demand of the
Trustee, the Company will pay to the Trustee for the benefit of the Holders of
the CVRs the whole amount, in Cash or Stock (in the Company's sole discretion),
that then shall have become due and payable on all CVRs (with interest from the
date due and payable to the date of such payment upon the overdue amount at the
Default Interest Rate); and, in addition thereto, such further amount as shall
be sufficient to cover the costs and expenses of collection, including
reasonable compensation to the Trustee and each predecessor Trustee, their
respective agents, attorneys and counsel, and any other amounts due the Trustee
under Section 406.

         In case the Company shall fail forthwith to pay such amounts upon such
demand, the Trustee, in its own name and as trustee of an express trust, shall
be entitled and empowered to institute any action or proceedings at law or in
equity for the collection of the sums so due and unpaid, and may prosecute any
such action or proceedings to judgment or final decree, and may enforce any such
judgment or final decree against the Company or other obligor upon such CVRs and
collect in the manner provided by law out of the property of the Company or
other obligor upon such CVRs, wherever situated, the moneys adjudged or decreed
to be payable.

         In case there shall be pending proceedings relative to the Company or
any other obligor upon the CVRs under Title 11 of the United States Code or any
other applicable Federal or State bankruptcy, insolvency or other similar law,
or in case a receiver, assignee or trustee in bankruptcy or reorganization,
liquidator, sequestrator or similar official shall have been appointed for or
taken possession of the Company or its property or such other obligor, or in
case of any other judicial proceedings relative to the Company or other obligor
upon the CVRs, or to the creditors or property of the Company or such other
obligor, the Trustee, irrespective of whether the principal of any CVRs shall
then be due and payable as therein expressed or otherwise and irrespective of
whether the Trustee shall have made any demand pursuant to the provisions of
this Section, shall be entitled and empowered, by intervention in such
proceedings or otherwise:

                  (a) to file and prove a claim or claims for the whole amount
         owing and unpaid in respect of the CVRs, and to file such other papers
         or documents as may be necessary or advisable in order to have the
         claims of the Trustee (including any claim for reasonable compensation
         to the Trustee

                                       29
<PAGE>

         and each predecessor Trustee, and their respective agents, attorneys
         and counsel, and for reimbursement of all expenses and liabilities
         incurred, and all advances made, by the Trustee and each predecessor
         Trustee, except as a result of negligence or bad faith) and of the
         Holders allowed in any judicial proceedings relative to the Company or
         other obligor upon the CVRs, or to the creditors or property of the
         Company or such other obligor;

                  (b) unless prohibited by applicable law and regulations, to
         vote on behalf of the Holders in any election of a trustee or a standby
         trustee in arrangement, reorganization, liquidation or other bankruptcy
         or insolvency proceedings or person performing similar functions in
         comparable proceedings; and

                  (c) to collect and receive any moneys or other property
         payable or deliverable on any such claims, and to distribute all
         amounts receivable with respect to the claims of the Holders and of the
         Trustee on their behalf and any trustee, receiver, or liquidator,
         custodian or other similar official is hereby authorized by each of the
         Holders to make payments to the Trustee, and, in the event that the
         Trustee shall consent to the making of payments directly to the
         Holders, to pay to the Trustee such amounts as shall be sufficient to
         cover reasonable compensation to the Trustee, each predecessor Trustee
         and their respective agents, attorneys and counsel, and all other
         expenses and liabilities incurred, and all advances made, by the
         Trustee and each predecessor Trustee except as a result of negligence
         or bad faith and all other amounts due to the Trustee or any
         predecessor Trustee pursuant to Section 406.

         Nothing herein contained shall be deemed to authorize the Trustee to
authorize or consent to or vote for or accept or adopt on behalf of any Holder
any plan of reorganization, arrangement, adjustment or composition affecting the
CVRs or the rights of any Holder thereof, or to authorize the Trustee to vote in
respect of the claim of any Holder in any such proceeding except, as aforesaid,
to vote for the election of a trustee in bankruptcy or similar person.

         All rights of action and of asserting claims under this Agreement, or
under any of the CVRs, may be enforced by the Trustee without the possession of
any of the CVRs or the production thereof at any trial or other proceedings
relative thereto, and any such action or proceedings instituted by the Trustee
shall be brought in its own name as trustee of an express trust, and any
recovery of judgment, subject to the payment of the expenses, disbursements and
compensation of the Trustee, each predecessor Trustee and their respective
agents and attorneys, shall be for the ratable benefit of the Holders.

         In any proceedings brought by the Trustee (and also any proceedings
involving the interpretation of any provision of this Agreement to which the
Trustee shall be a party) the Trustee shall be held to represent all the
Holders, and it shall not be necessary to make any Holders of such CVRs parties
to any such proceedings.

Section 803.  Application of Proceeds.

         Any monies (including CVRs or Shares) collected by the Trustee pursuant
to this Article in respect of any CVRs shall be applied in the following order
at the date or dates fixed by the Trustee upon presentation of the several CVRs
in respect of which monies (including CVRs or Shares) have been collected and
stamping (or otherwise noting) thereon the payment in exchange for the presented
CVRs if only partially paid or upon surrender thereof if fully paid:

                  FIRST: To the payment of costs and expenses in respect of
         which monies have been collected, including reasonable compensation to
         the Trustee and each predecessor Trustee and their respective agents
         and attorneys and of all expenses and liabilities incurred, and all
         advances made, by the Trustee and each predecessor Trustee except as a
         result of negligence or bad faith, and all other amounts due to the
         Trustee or any predecessor Trustee pursuant to Section 406;

                  SECOND: To the payment of the whole amount then owing and
         unpaid upon all the CVRs, with interest at the Default Interest Rate on
         all such amounts, and in case such moneys

                                       30
<PAGE>

         shall be insufficient to pay in full the whole amount so due and unpaid
         upon the CVRs, then to the payment of such amounts without preference
         or priority of any CVR over any other CVR, ratably to the aggregate of
         such amounts due and payable; and

                  THIRD:  To the payment of the remainder, if any, to the
         Company or any other Person lawfully entitled thereto.

Section 804.  Suits for Enforcement.

         In case an Event of Default has occurred, has not been waived and is
continuing, the Trustee may in its discretion proceed to protect and enforce the
rights vested in it by this Agreement by such appropriate judicial proceedings
as the Trustee shall deem most effectual to protect and enforce any of such
rights, either at law or in equity or in bankruptcy or otherwise, whether for
the specific enforcement of any covenant or agreement contained in this
Agreement or in aid of the exercise of any power granted in this Agreement or to
enforce any other legal or equitable right vested in the Trustee by this
Agreement or by law.

Section 805.  Restoration of Rights on Abandonment of Proceedings.

         In case the Trustee shall have proceeded to enforce any right under
this Agreement and such proceedings shall have been discontinued or abandoned
for any reason, or shall have been determined adversely to the Trustee, then and
in every such case the Company and the Trustee shall be restored respectively to
their former positions and rights hereunder, and all rights, remedies and powers
of the Company, the Trustee and the Holders shall continue as though no such
proceedings had been taken.

Section 806.  Limitations on Suits by Holders.

         No Holder of any CVR shall have any right by virtue or by availing
itself of any provision of this Agreement to institute any action or proceeding
at law or in equity or in bankruptcy or otherwise upon or under or with respect
to this Agreement, or for the appointment of a trustee, receiver, liquidator,
custodian or other similar official or for any other remedy hereunder, unless
such Holder previously shall have given to the Trustee written notice of default
and of the continuance thereof as hereinbefore provided, and unless also the
Holders of not less than 25% of the CVRs then Outstanding shall have made
written request upon the Trustee to institute such action or proceedings in its
own name as trustee hereunder and shall have offered to the Trustee such
reasonable indemnity as it may require against the costs, expenses and
liabilities to be incurred therein or thereby and the Trustee for 60 days after
its receipt of such notice, request and offer of indemnity shall have failed to
institute any such action or proceeding and no direction inconsistent with such
written request shall have been given to the Trustee pursuant to Section 809; it
being understood and intended, and being expressly covenanted by the taker and
Holder of every CVR with every other taker and Holder and the Trustee, that no
one or more Holders of CVRs shall have any right in any manner whatever by
virtue or by availing itself or themselves of any provision of this Agreement to
effect, disturb or prejudice the rights of any other such Holder of CVRs, or to
obtain or seek to obtain priority over or preference to any other such Holder or
to enforce any right under this Agreement, except in the manner herein provided
and for the equal, ratable and common benefit of all Holders of CVRs. For the
protection and enforcement of the provisions of this Section, each and every
Holder and the Trustee shall be entitled to such relief as can be given either
at law or in equity.

Section 807.  Unconditional Right of Holders to Institute Certain Suits.

         Notwithstanding any other provision in this Agreement and any provision
of any CVR, the right of any Holder of any CVR to receive payment of the amounts
payable in respect of such CVR on or after the respective due dates expressed in
such CVR, or to institute suit for the enforcement of any such payment on or
after such respective dates, shall not be impaired or affected without the
consent of such Holder.

Section 808.  Powers and Remedies Cumulative; Delay or Omission Not Waiver of
              Default.

                                       31
<PAGE>

         Except as provided in Section 806, no right or remedy herein conferred
upon or reserved to the Trustee or to the Holders is intended to be exclusive of
any other right or remedy, and every right and remedy shall, to the extent
permitted by law, be cumulative and in addition to every other right and remedy
given hereunder or now or hereafter existing at law or in equity or otherwise.
The assertion or employment of any right or remedy hereunder, or otherwise,
shall not prevent the concurrent assertion or employment of any other
appropriate right or remedy.

         No delay or omission of the Trustee or of any Holder to exercise any
right or power accruing upon any Event of Default occurring and continuing as
aforesaid shall impair any such right or power or shall be construed to be a
waiver of any such Event of Default or an acquiescence therein; and, subject to
Section 806, every power and remedy given by this Agreement or by law to the
Trustee or to the Holders may be exercised from time to time, and as often as
shall be deemed expedient, by the Trustee or by the Holders.

Section 809.  Control by Holders.

         The Holders of a majority of the CVRs at the time Outstanding shall
have the right to direct the time, method, and place of conducting any
proceeding for any remedy available to the Trustee, or exercising any trust or
power conferred on the Trustee with respect to the CVRs by this Agreement;
provided that such direction shall not be otherwise than in accordance with law
and the provisions of this Agreement; and provided further that (subject to the
provisions of Section 401) the Trustee shall have the right to decline to follow
any such direction if the Trustee, being advised by counsel, shall determine
that the action or proceeding so directed may not lawfully be taken or if the
Trustee in good faith by its board of directors, the executive committee, or a
trust committee of directors or Responsible Officers of the Trustee shall
determine that the action or proceedings so directed would involve the Trustee
in personal liability or if the Trustee in good faith shall so determine that
the actions or forbearances specified in or pursuant to such direction would be
unduly prejudicial to the interests of Holders of the CVRs not joining in the
giving of said direction, it being understood that (subject to Section 401) the
Trustee shall have no duty to ascertain whether or not such actions or
forbearances are unduly prejudicial to such Holders.

         Nothing in this Agreement shall impair the right of the Trustee in its
discretion to take any action deemed proper by the Trustee and which is not
inconsistent with such direction or directions by Holders.

Section 810.  Waiver of Past Defaults.

         Prior to the declaration of the acceleration of the maturity of the
CVRs as provided in Section 801, in the case of a default or an Event of Default
specified in clause (b), (c) or (d) of Section 801, the Holders of a majority of
all the CVRs then Outstanding may waive any such default or Event of Default,
and its consequences, except a default in respect of a covenant or provisions
hereof which cannot be modified or amended without the consent of the Holder of
each CVR affected. In the case of any such waiver, the Company, the Trustee and
the Holders of the CVRs shall be restored to their former positions and rights
hereunder, respectively; but no such waiver shall extend to any subsequent or
other default or impair any right consequent thereon.

         Upon any such waiver, such default shall cease to exist and be deemed
to have been cured and not to have occurred, and any Event of Default arising
therefrom shall be deemed to have been cured, and not to have occurred for every
purpose of this Agreement; but no such waiver shall extend to any subsequent or
other default or Event of Default or impair any right consequent thereon.

Section 811.  Trustee to Give Notice of Default, but May Withhold in Certain
              Circumstances.

         The Trustee shall transmit to the Holders, as the names and addresses
of such Holders appear on the Security Register, notice by mail of all defaults
which have occurred, such notice to be transmitted within 90 days after the
Trustee is notified or has actual knowledge of the occurrence thereof unless
such defaults shall have been cured before the giving of such notice (the term
"default" or "defaults" for the

                                       32
<PAGE>

purposes of this Section being hereby defined to mean any event or condition
which is, or with notice or lapse of time or both would become, an Event of
Default); provided that, except in the case of default in the payment of the
amounts payable in respect of any of the CVRs, the Trustee shall be protected in
withholding such notice if and so long as the board of directors, the executive
committee, or a trust committee of directors or trustees and/or Responsible
Officers of the Trustee in good faith determines that the withholding of such
notice is in the interests of the Holders.

Section 812.  Right of Court to Require Filing of Undertaking to Pay Costs.

         All parties to this Agreement agree, and each Holder of any CVR by his
acceptance thereof shall be deemed to have agreed, that any court may in its
discretion require, in any suit for the enforcement of any right or remedy under
this Agreement or in any suit against the Trustee for any action taken, suffered
or omitted by it as Trustee, the filing by any party litigant in such suit of an
undertaking to pay the costs of such suit, and that such court may in its
discretion assess reasonable costs, including reasonable attorneys' fees,
against any party litigant in such suit, having due regard to the merits and
good faith or the claims or defenses made by such party litigant; but the
provisions of this Section shall not apply to any suit instituted by the
Trustee, to any suit instituted by any Holder or group of Holders holding in the
aggregate more than 10% of the CVRs Outstanding or to any suit instituted by any
Holder for the enforcement of the payment of any CVR on or after the due date
expressed in such CVR.

                                  ARTICLE NINE

                    CONSOLIDATION, MERGER, SALE OR CONVEYANCE

Section 901.  Company May Consolidate, Etc.

         The Company shall not consolidate with or merge into any other Person
or convey, transfer or lease its properties and assets substantially as an
entirety to any Person, unless:

                  (1) in case the Company shall consolidate with or merge into
         any other Person or convey, transfer or lease its properties and assets
         substantially as an entirety to any Person, the Person formed by such
         consolidation or into which the Company is merged or the Person which
         acquires by conveyance or transfer, or which leases, the properties and
         assets of the Company substantially as an entirety (the "Surviving
         Person") shall be a corporation, partnership or trust organized and
         existing under the laws of the United States of America, any state
         thereof or the District of Columbia, the United Kingdom, Bermuda, the
         Republic of Ireland, Barbados, the Channel Islands, the Cayman Islands
         or any other jurisdiction that is not materially adverse to the Holders
         and shall expressly assume payment of amounts on all the CVRs and the
         performance of every covenant of this Agreement on the part of the
         Company to be performed or observed;

                  (2) immediately after giving effect to such transaction, no
         Event of Default shall have happened and be continuing; and

                  (3) the Company has delivered to the Trustee an Officer's
         Certificate stating that such consolidation, merger, conveyance,
         transfer or lease complies with this Article and that all conditions
         precedent herein provided for relating to such transaction have been
         complied with.

         Solely for purposes of this Section 901, "convey, transfer or lease its
properties and assets substantially as an entirety" shall mean properties and
assets contributing in the aggregate at least 80% of the Company's total
revenues as reported in the Company's last available periodic financial report
(quarterly or annual, as the case may be) filed with the Commission.

Section 902.  Successor Substituted.

                                       33
<PAGE>

         Upon any consolidation of or merger by the Company with or into any
other Person, or any conveyance, transfer or lease of the properties and assets
substantially as an entirety to any Person in accordance with Section 901, the
Surviving Person shall succeed to, and be substituted for, and may exercise
every right and power of, the Company under this Agreement with the same effect
as if the Surviving Person had been named as the Company herein, and thereafter,
the predecessor corporation shall be relieved of all obligations and covenants
under this Agreement and the CVRs.

Section 903.  Opinion of Counsel to Trustee.

         The Trustee, subject to the provisions of Sections 401 and 402, may
receive an Opinion of Counsel, prepared in accordance with Sections 103 and 104,
as conclusive evidence that any such consolidation, merger, sale, lease or
conveyance, and any such assumption, and any such liquidation or dissolution,
complies with the applicable provisions of this Agreement.

                                       34
<PAGE>

                                 * * * * * * *

         This Agreement may be signed in any number of counterparts with the
same effect as if the signatures to each counterpart were upon a single
instrument, and all such counterparts together shall be deemed an original of
this Agreement.

         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed, and their respective corporate seals to be hereunto affixed and
attested, all as of the day and year first above written.

                                     MARKEL HOLDINGS INC.



                                     By:    /s/ Darrell D. Martin
                                            --------------------------
                                     Name:  Darrell D. Martin
                                     Title: Executive Vice President and
                                            Chief Financial Officer
Attest:

/s/ Gregory B. Nevers
----------------------
Name: Gregory B. Nevers
Title: Secretary

                                     The Chase Manhattan Bank, as Trustee



                                     By:    /s/ Philbert G. Jones
                                            --------------------------
                                     Name:  Philbert G. Jones
                                     Title: Assistant Vice President

Attest:

/s/ J. Adamis
---------------------
Name: J. Adamis
Title: Vice President

                                       35
<PAGE>

State of Virginia)
                 )    ss.:
County of Henrico)


         On the 17th day of March 2000, before me personally came Darrell D.
Martin, to me known, who, being by me duly sworn, did depose and say that s/he
resides at ; that s/he is Executive Vice President and Chief Financial Officer
of Markel Holdings Inc., one of the corporations described in and which executed
the above instrument; and s/he knows the corporate seal of such corporation;
that the seal affixed to said instrument is such corporate seal; that it was so
affixed pursuant to authority of the Board of Directors of such corporation; and
that s/he signed her/his name thereto pursuant to like authority.

                                            (NOTARIAL SEAL)



                                            /s/ Jean Childres
                                            ---------------------------

 State of New York)
                  )    ss.:
County of New York)

         On the 21st day of March 2000, before me personally came Philbert G.
Jones, to me known, who, being by me duly sworn, did depose and say that s/he
resides at ; that s/he is Assistant Vice President of The Chase Manhattan Bank,
one of the corporations described in and which executed the above instrument;
and s/he knows the corporate seal of such corporation; that the seal affixed to
said instrument is such corporate seal; that it was so affixed pursuant to
authority of the Board of Directors of such corporation; and that s/he signed
her/his name thereto pursuant to like authority.

                                            (NOTARIAL SEAL)



                                           /s/ Emily Fayan
                                           ------------------------

                                       36