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                                                                   EXHIBIT 4.11



                             PATTERSON ENERGY, INC.

                                       and

                        [------------------------------],
                                  As Depositary

                                       and

                         HOLDERS OF DEPOSITARY RECEIPTS

                                 --------------

                           FORM OF DEPOSIT AGREEMENT*

                                 --------------

                            Dated as of [__________]




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*Complete or modify the provisions of this Form as appropriate to reflect the
terms of the Depositary Shares and Depositary Receipts.



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                                TABLE OF CONTENTS



                                                                                                               Page
                                                                                                               ----
                                                                                                              
                                                             ARTICLE 1
                                                            DEFINITIONS

   Certificate of Incorporation...................................................................................1
   Certificate of Designation.....................................................................................1
   Common Stock...................................................................................................1
   Corporate Office...............................................................................................1
   Deposit Agreement..............................................................................................1
   Depositary.....................................................................................................1
   Depositary Share...............................................................................................1
   Depositary's Agent.............................................................................................2
   New York Office................................................................................................2
   Receipt........................................................................................................2
   Record holder..................................................................................................2
   Registrar......................................................................................................2
   Securities Act.................................................................................................2
   Stock..........................................................................................................2

                                                             ARTICLE 2
                                    FORM OF RECEIPTS, DEPOSIT OF STOCK, EXECUTION AND DELIVERY,
                                     TRANSFER, SURRENDER, REDEMPTION AND CONVERSION OF RECEIPTS

   SECTION 2.1       Form and Transfer of Receipts................................................................2
   SECTION 2.2       Deposit of Stock; Execution and Delivery of Receipts in Respect Thereof......................3
   SECTION 2.3       Redemption and Conversion of Stock...........................................................3
   SECTION 2.4       Register of Transfer of Receipts.............................................................5
   SECTION 2.5       Combination and Split-ups of Receipts........................................................6
   SECTION 2.6       Surrender of Receipts and Withdrawal of Stock................................................6
   SECTION 2.7       Limitations on Execution and Delivery, Transfer, Split-up, Combination,
                     Surrender and Exchange of Receipts and Withdrawal or Deposit of Stock........................6
   SECTION 2.8       Lost Receipts, etc...........................................................................7
   SECTION 2.9       Cancellation and Destruction of Surrendered Receipts.........................................7

                                                             ARTICLE 3
                                      CERTAIN OBLIGATIONS OF HOLDERS OF RECEIPTS AND PATTERSON

   SECTION 3.1       Filing Proofs, Certificates and Other Information............................................7
   SECTION 3.2       Payment of Taxes or Other Governmental Charges...............................................7
   SECTION 3.3       Withholding..................................................................................8
   SECTION 3.4       Representations and Warranties as to Stock...................................................8

                                                             ARTICLE 4
                                                         THE STOCK, NOTICES

   SECTION 4.1       Cash Distributions...........................................................................8
   SECTION 4.2       Distributions Other Than Cash................................................................8
   SECTION 4.3       Subscription Rights, Preferences or Privileges...............................................9



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   SECTION 4.4       Notice of Dividends, Fixing of Record Date for Holders of Receipts...........................9
   SECTION 4.5       Voting Rights................................................................................9
   SECTION 4.6       Changes Affecting Stock and Reclassifications, Recapitalizations, etc.......................10
   SECTION 4.7       Reports.....................................................................................10
   SECTION 4.8       Lists of Receipt Holders....................................................................10

                                                             ARTICLE 5
                                              THE DEPOSITARY, THE DEPOSITARY'S AGENTS,
                                                   THE REGISTRAR AND THE COMPANY

   SECTION 5.1       Maintenance of Offices, Agencies, Transfer Books by the Depositary;
                     the Registrar...............................................................................10
   SECTION 5.2       Prevention or Delay in Performance by the Depositary, the Depositary's Agents,
                     the Registrar or Patterson..................................................................11
   SECTION 5.3       Obligations of the Depositary, the Depositary's Agents, the Registrar
                     and Patterson...............................................................................11
   SECTION 5.4       Resignation and Removal of the Depositary, Appointment of Successor
                     Depositary..................................................................................12
   SECTION 5.5       Corporate Notices and Reports...............................................................13
   SECTION 5.6       Deposit of Stock by Patterson...............................................................13
   SECTION 5.7       Indemnification by Patterson................................................................13
   SECTION 5.8       Fees, Charges and Expenses..................................................................13

                                                             ARTICLE 6
                                                     AMENDMENT AND TERMINATION

   SECTION 6.1       Amendment...................................................................................13
   SECTION 6.2       Termination.................................................................................14

                                                             ARTICLE 7
                                                           MISCELLANEOUS

   SECTION 7.1       Counterparts................................................................................14
   SECTION 7.2       Exclusive Benefits of Parties...............................................................14
   SECTION 7.3       Invalidity of Provisions....................................................................14
   SECTION 7.4       Notices.....................................................................................15
   SECTION 7.5       Depositary's Agents.........................................................................15
   SECTION 7.6       Holders of Receipts Are Parties.............................................................15
   SECTION 7.7       Law.........................................................................................15
   SECTION 7.8       Headings....................................................................................15



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                                DEPOSIT AGREEMENT

         THIS DEPOSIT AGREEMENT, dated as of [________], among Patterson Energy,
Inc., a Delaware corporation ("Patterson"), [_________________________________],
a [________] banking corporation, as Depositary, and all holders from time to
time of Receipts issued hereunder.

                              W I T N E S S E T H:

         WHEREAS, Patterson desires to provide as hereinafter set forth in this
Deposit Agreement, for the deposit of shares of Stock with the Depositary, as
agent for the beneficial owners of the Stock, for the purposes set forth in this
Deposit Agreement and for the issuance hereunder of the Receipts evidencing
Depositary Shares representing an interest in the Stock so deposited; and

         WHEREAS, the Receipts are to be substantially in the form annexed as
Exhibit A to this Deposit Agreement, with appropriate insertions, modifications
and omissions, as hereinafter provided in this Deposit Agreement.

         NOW, THEREFORE, in consideration of the premises contained herein, it
is agreed by and among the parties hereto as follows:

                                    ARTICLE 1
                                   DEFINITIONS

         The following definitions shall apply to the respective terms (in the
singular and plural forms of such terms) used in this Deposit Agreement and the
Receipts:

         "Certificate of Incorporation" shall mean the Restated Certificate of
Incorporation, as amended and restated from time to time, of Patterson.

         "Certificate of Designation" shall mean the Certificate of Designations
establishing and setting forth the rights, preferences, privileges and
limitations of the Stock.

         "Common Stock" shall mean Patterson's Common Stock, par value $.01 per
share.

         "Corporate Office" shall mean the office of the Depositary in
[__________], [______________] at which at any particular time its business in
respect of matters governed by this Deposit Agreement shall be administered,
which at the date of this Deposit Agreement is located at
[______________________].

         "Deposit Agreement" shall mean this agreement, as the same may be
amended, modified or supplemented from time to time.

         "Depositary" shall mean [_____________________], as Depositary
hereunder, and any successor as Depositary hereunder.

         "Depositary Share" shall mean the rights evidenced by the Receipts
executed and delivered hereunder, including the interests in Stock granted to
holders of Receipts pursuant to the terms and conditions of the Deposit
Agreement. Each Depositary Share shall represent an interest in [fraction] of a
share of Stock deposited with the Depositary hereunder and the same
proportionate interest in any and all other property received by the Depositary
in respect of such share of Stock and held under this Deposit Agreement. Subject
to the terms of this Deposit Agreement, each record holder of a Receipt
evidencing a Depositary Share or Shares is entitled, proportionately, to all the
rights, preferences and privileges of the



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Stock represented by such Depositary Share or Shares, including the dividend,
voting and liquidation rights contained in the Certificate of Designation, and
to the benefits of all obligations and duties of Patterson in respect of the
Stock under the Certificate of Designation and the Certificate of Incorporation.

         "Depositary's Agent" shall mean an agent appointed by the Depositary as
provided, and for the purposes specified, in Section 7.5.

         ["New York Office" shall mean the facility maintained by the Depositary
in the Borough of Manhattan, The City of New York for accepting, executing and
delivering Receipts and other instruments prior to processing such instruments
at the Corporate Office, which facility at the date of this Deposit Agreement is
located at [____________.]

         "Receipt" shall mean a Depositary Receipt executed and delivered
hereunder, in substantially the form of Exhibit A hereto, evidencing a
Depositary Share or Shares, as the same may be amended from time to time in
accordance with the provisions hereof.

         "Record holder" or "holder" as applied to a Receipt shall mean the
person in whose name a Receipt is registered on the books maintained by or on
behalf of the Depositary for such purpose.

         "Registrar" shall mean any bank or trust company appointed to register
ownership and transfers of Receipts as herein provided.

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

         "Stock" shall mean shares of Patterson's [name of series] Preferred
Stock, $.01 par value per share.

                                    ARTICLE 2
                  FORM OF RECEIPTS, DEPOSIT OF STOCK, EXECUTION
                       AND DELIVERY, TRANSFER, SURRENDER,
                      REDEMPTION AND CONVERSION OF RECEIPTS

         SECTION 2.1  Form and Transfer of Receipts. Receipts shall be
engraved or printed or lithographed and shall be substantially in the form set
forth in Exhibit A annexed to this Deposit Agreement, with appropriate
insertions, modifications and omissions, as hereinafter provided. Receipts shall
be executed by the Depositary by the manual signature of a duly authorized
signatory of the Depositary; provided, however, that such signature may be a
facsimile if a Registrar (other than the Depositary) shall have countersigned
the Receipts by manual signature of a duly authorized signatory of the
Registrar. No Receipt shall be entitled to any benefits under this Deposit
Agreement or be valid or obligatory for any purpose unless it shall have been
executed as provided in the preceding sentence. The Depositary shall record on
its books each Receipt executed as provided above and delivered as hereinafter
provided. Receipts bearing the facsimile signature of anyone who was at any time
a duly authorized officer of the Depositary shall bind the Depositary,
notwithstanding that such officer has ceased to hold such office prior to the
delivery of such Receipts.

         Receipts may be issued in denominations of any number of whole
Depositary Shares. All Receipts shall be dated the date of their execution.

         Receipts may be endorsed with or have incorporated in the text thereof
such legends or recitals or changes not inconsistent with the provisions of this
Deposit Agreement as may be required by the Depositary or required to comply
with any applicable law or regulation or with the rules and regulations



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of any securities exchange upon which the Stock or the Depositary Shares may be
listed or to conform with any usage with respect thereto, or to indicate any
special limitations or restrictions to which any particular Receipts are subject
by reason of the date of issuance of the Stock or otherwise.

         Title to any Receipt (and to the Depositary Shares evidenced by such
Receipt) that is properly endorsed or accompanied by a properly executed
instrument of transfer shall be transferable by delivery with the same effect as
in the case of a negotiable instrument; provided, however, that the Depositary
may, notwithstanding any notice to the contrary, treat the record holder thereof
at such time as the absolute owner thereof for the purpose of determining the
person entitled to distributions of dividends or other distributions or to any
notice provided for in this Deposit Agreement and for all other purposes.

         SECTION 2.2 Deposit of Stock; Execution and Delivery of Receipts in
Respect Thereof. Subject to the terms and conditions of this Deposit Agreement,
Patterson or any holder of Stock may deposit such Stock under this Deposit
Agreement by delivery to the Depositary of a certificate or certificates for the
Stock to be deposited, properly endorsed or accompanied, if required by the
Depositary, by a properly executed instrument of transfer in form satisfactory
to the Depositary, together with (i) all such certifications as may be required
by the Depositary in accordance with the provisions of this Deposit Agreement
and (ii) a written order of Patterson or such holder, as the case may be,
directing the Depositary to execute and deliver to or upon the written order of
the person or persons stated in such order a Receipt or Receipts for the number
of Depositary Shares representing such deposited Stock.

         Upon receipt by the Depositary of a certificate or certificates for
Stock to be deposited hereunder, together with the other documents specified
above, the Depositary shall, as soon as transfer and registration can be
accomplished, present such certificate or certificates to the registrar and
transfer agent of the Stock for transfer and registration in the name of the
Depositary or its nominee of the Stock being deposited.

         Deposited Stock shall be held by the Depositary in an account to be
established by the Depositary at the Corporate Office.

         Upon receipt by the Depositary of a certificate or certificates for
Stock to be deposited hereunder, together with the other documents specified
above, the Depositary, subject to the terms and conditions of this Deposit
Agreement, shall execute and deliver, to or upon the order of the person or
persons named in the written order delivered to the Depositary referred to in
the first paragraph of this Section 2.2, a Receipt or Receipts for the number of
whole Depositary Shares representing the Stock so deposited and registered in
such name or names as may be requested by such person or persons. The Depositary
shall execute and deliver such Receipt or Receipts at the New York Office,
except that, at the request, risk and expense of any person requesting such
delivery and for the account of such person, such delivery may be made at such
other place as may be designated by such person. In each case, delivery will be
made only upon payment by such person to the Depositary of all taxes and other
governmental charges and any fees payable in connection with such deposit and
the transfer of the deposited Stock.

         Patterson shall deliver to the Depositary from time to time such
quantities of Receipts as the Depositary may request to enable the Depositary to
perform its obligations under this Deposit Agreement.

         SECTION 2.3  Redemption and Conversion of Stock.* Whenever
Patterson shall elect to redeem or be required to convert shares of Stock into
shares of Common Stock or other securities in accordance with the Certificate of
Designation, it shall (unless otherwise agreed in writing with the Depositary)
give the Depositary in its capacity as Depositary not less than five business
days' prior notice of the proposed

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*This section to be modified to discuss specific redemption or conversion terms
of the Stock, if any.


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date of the mailing of a notice of redemption or conversion of Stock and the
simultaneous redemption or conversion of the Depositary Shares representing the
Stock to be redeemed or converted and of the number of such shares of Stock held
by the Depositary to be redeemed or converted. The Depositary shall, as directed
by Patterson in writing, mail, first class postage prepaid, notice of the
redemption or conversion of Stock and the proposed simultaneous redemption or
conversion of the Depositary Shares representing the Stock to be redeemed or
converted, not less than 30 and not more than 60 days prior to the date fixed
for redemption or conversion of such Stock and Depositary Shares, to the record
holders of the Receipts evidencing the Depositary Shares to be so redeemed or
converted, at the addresses of such holders as the same appear on the records of
the Depositary; provided, that if the effectiveness of a Merger or Consolidation
(as defined in the Certificate of Designation) makes it impracticable to provide
at least 30 days' notice, the Depositary shall provide such notice as soon as
practicable prior to such effectiveness. Any such notice shall also be published
in the same manner as notices of redemption or conversion of Stock are required
to be published pursuant to Section [ ] of the Certificate of Designation.
Notwithstanding the foregoing, neither failure to mail or publish any such
notice to one or more such holders nor any defect in any notice shall affect the
sufficiency of the proceedings for redemption or conversion. Patterson shall
provide the Depositary with such notice, and each such notice shall state: the
redemption or conversion date; the number of Depositary Shares to be redeemed or
converted; if fewer than all the Depositary Shares held by any holder are to be
redeemed, the number of such Depositary Shares held by such holder to be so
redeemed; in the case of a call for redemption, the call price payable upon
redemption and the Current Market Price (as defined in the Certificate of
Designation) to be used to calculate the number of shares of Common Stock or
other securities deliverable upon redemption; whether Patterson is exercising
any option to deliver shares of Common Stock or other securities in lieu of any
cash consideration pursuant to Section [ ] of the Certificate of Designation and
the Current Market Price to be used to calculate the number of such shares or
other securities; the place or places where Receipts evidencing Depositary
Shares to be redeemed or converted are to be surrendered for redemption or
conversion; whether Patterson is depositing with a bank or trust company on or
before the redemption or conversion date, the shares of Common Stock or other
securities and cash, if any, payable by Patterson and the proposed date of such
deposit; the amount of accrued and unpaid dividends payable per share of Stock
to be redeemed or converted to and including such redemption or conversion date,
as the case may be, and that dividends in respect of the Stock represented by
the Depositary Shares to be redeemed or converted will cease to accrue on such
redemption or conversion date (unless Patterson shall default in delivering
shares of Common Stock or other securities and cash, if any, at the time and
place specified in such notice). On the date of any such redemption or
conversion, the Depositary shall surrender the certificate or certificates held
by the Depositary evidencing the number of shares of Stock to be redeemed or
converted in the manner specified in the notice of redemption or conversion of
Stock provided by Patterson pursuant to Section [ ] of the Certificate of
Designation. The Depositary shall, thereafter, redeem or convert the number of
Depositary Shares representing such redeemed or converted Stock upon the
surrender of Receipts evidencing such Depositary Shares in the manner provided
in the notice sent to record holders of Receipts; provided, that the Depositary
shall have received, upon surrendering such certificate or certificates as
aforesaid, a sufficient number of shares of Common Stock or other securities to
convert or redeem such number of Depositary Shares (including, in the event that
Patterson elects pursuant to Section [ ] of the Certificate of Designation to
exercise any option to deliver shares of Common Stock or other securities in
lieu of any cash consideration payable on the Effective Date (as defined in the
Certificate of Designation) of any Merger or Consolidation, a number of shares
of Common Stock equal to such cash consideration (as determined in the manner
set forth in the Certificate of Designation)), plus any accrued and unpaid
dividends payable with respect thereto to and including the date of any such
redemption or conversion and any other cash consideration payable on the
Effective Date of a Merger or Consolidation (other than any dividends or other
cash consideration payable on the Effective Date of a Merger or Consolidation
that Patterson has elected to pay in shares of Common Stock pursuant to Section
[ ] of the Certificate of Designation) as instructed and calculated by
Patterson. In case fewer than all the outstanding Depositary Shares are to be
redeemed, the Depositary Shares to be


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redeemed shall be selected by the Depositary by lot, on a pro rata basis or such
other equitable method as shall be approved by Patterson and the Depositary.

         Notice having been mailed by the Depositary as aforesaid, from and
after the redemption or conversion date (unless Patterson shall have failed to
redeem or convert the shares of Stock to be redeemed or converted by it upon the
surrender of the certificate or certificates therefor by the Depositary as
described in the preceding paragraph), the Depositary Shares called for
redemption or subject to conversion shall be deemed no longer to be outstanding
and all rights of the holders of Receipts evidencing such Depositary Shares
(except the right to receive the shares of Common Stock or other securities and
cash, if any, payable upon redemption or conversion upon surrender of such
Receipts) shall, to the extent of such Depositary Shares, cease and terminate.
Upon surrender in accordance with said notice of the Receipts evidencing such
Depositary Shares (properly endorsed or assigned for transfer, if the Depositary
shall so require), such Depositary Shares shall be converted into or redeemed
for shares of Common Stock or other securities at a rate equal to [ ] of the
number of shares of Common Stock or other securities delivered, and the holders
thereof shall be entitled to [ ] of the cash, if any, payable, in respect of the
shares of Stock pursuant to the Certificate of Designation. The foregoing shall
be subject further to the terms and conditions of the Certificate of
Designation.

         If fewer than all of the Depositary Shares evidenced by a Receipt are
called for redemption, the Depositary will deliver to the holder of such Receipt
upon its surrender to the Depositary, together with the shares of Common Stock
or other securities and all accrued and unpaid dividends to and including the
date fixed for redemption payable in respect of the Depositary Shares called for
redemption, a new Receipt evidencing the Depositary Shares evidenced by such
prior Receipt and not called for redemption.

         To the extent that Depositary Shares are converted into or redeemed for
shares of Common Stock or other securities and all of such shares of Common
Stock or other securities cannot be distributed to the record holders of
Receipts converted or called for redemption without creating fractional
interests in such shares, the Depositary may, with the consent of Patterson,
adopt such method as it deems equitable and practicable for the purpose of
effecting such distribution, including the sale (at public or private sale) of
such shares of Common Stock or other securities at such place or places and upon
such terms as it may deem proper, and the net proceeds of any such sale shall,
subject to Section 3.2, be distributed or made available for distribution to
such record holders that would otherwise receive fractional interests in such
shares of Common Stock or other securities.

         The Depositary shall not be required (a) to issue, transfer or exchange
any Receipts for a period beginning at the opening of business 15 days next
preceding any selection of Depositary Shares and Stock to be redeemed and ending
at the close of business on the day of the mailing of notice of redemption of
Depositary Shares or (b) to transfer or exchange for another Receipt any Receipt
evidencing Depositary Shares called or being called for redemption, in whole or
in part, or subject to conversion except as provided in the second preceding
paragraph of this Section 2.3.

         SECTION 2.4  Register of Transfer of Receipts. Subject to the
terms and conditions of this Deposit Agreement, the Depositary shall register on
its books from time to time transfers of Receipts upon any surrender thereof at
the Corporate Office, the New York Office or such other office as the Depositary
may designate for such purpose, by the record holder in person or by a duly
authorized attorney, properly endorsed or accompanied by a properly executed
instrument of transfer, together with evidence of the payment of any transfer
taxes as may be required by law. Upon such surrender, the Depositary shall
execute a new Receipt or Receipts and deliver the same to or upon the order of
the person entitled thereto evidencing the same aggregate number of Depositary
Shares evidenced by the Receipt or Receipts surrendered.


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         SECTION 2.5  Combination and Split-ups of Receipts. Upon surrender
of a Receipt or Receipts at the Corporate Office, the New York Office or such
other office as the Depositary may designate for the purpose of effecting a
split-up or combination of Receipts, subject to the terms and conditions of this
Deposit Agreement, the Depositary shall execute and deliver a new Receipt or
Receipts in the authorized denominations requested evidencing the same aggregate
number of Depositary Shares evidenced by the Receipt or Receipts surrendered;
provided, however, that the Depositary shall not issue any Receipt evidencing a
fractional Depositary Share.

         SECTION 2.6  Surrender of Receipts and Withdrawal of Stock.* Any
holder of a Receipt or Receipts may withdraw any or all of the Stock (but only
in whole shares of Stock) represented by the Depositary Shares evidenced by such
Receipts and all money and other property, if any, represented by such
Depositary Shares by surrendering such Receipt or Receipts at the Corporate
Office, the New York Office or at such other office as the Depositary may
designate for such withdrawals. After such surrender, without unreasonable
delay, the Depositary shall deliver to such holder, or to the person or persons
designated by such holder as hereinafter provided, the whole number of shares of
Stock and all such money and other property, if any, represented by the
Depositary Shares evidenced by the Receipt or Receipts so surrendered for
withdrawal, but holders of such whole shares of Preferred Stock will not
thereafter be entitled to deposit such Preferred Stock hereunder or to receive
Depositary Shares thereafter. If the Receipt or Receipts delivered by the holder
to the Depositary in connection with such withdrawal shall evidence a number of
Depositary Shares in excess of the number of whole Depositary Shares
representing the whole number of shares of Stock to be withdrawn, the Depositary
shall at the same time, in addition to such whole number of shares of Stock and
such money and other property, if any, to be withdrawn, deliver to such holder,
or (subject to Section 2.4) upon his order, a new Receipt or Receipts evidencing
such excess number of whole Depositary Shares. Delivery of the Stock and such
money and other property being withdrawn may be made by the delivery of such
certificates, documents of title and other instruments as the Depositary may
deem appropriate, which, if required by the Depositary, shall be properly
endorsed or accompanied by proper instruments of transfer. If the Stock and the
money and other property being withdrawn are to be delivered to a person or
persons other than the record holder of the Receipt or Receipts being
surrendered for withdrawal of Stock, such holder shall execute and deliver to
the Depositary a written order so directing the Depositary and the Depositary
may require that the Receipt or Receipts surrendered by such holder for
withdrawal of such shares of Stock be properly endorsed in blank or accompanied
by a properly executed instrument of transfer in blank and that the signature on
such instrument of transfer be guaranteed by an eligible guarantor institution
(banks, stockbrokers, savings and loan associations and credit unions with
membership in an approved signature guarantee medallion program) pursuant to
Rule 17Ad-15 of the Securities Exchange Act of 1934, as amended. The Depositary
shall deliver the Stock and the money and other property, if any, represented by
the Depositary Shares evidenced by Receipts surrendered for withdrawal, without
unreasonable delay, at the office at which such Receipts were surrendered,
except that, at the request, risk and expense of the holder surrendering such
Receipt or Receipts and for the account of the holder thereof, such delivery may
be made, without unreasonable delay, at such other place as may be designated by
such holder.

         SECTION 2.7  Limitations on Execution and Delivery, Transfer,
Split-up, Combination, Surrender and Exchange of Receipts and Withdrawal or
Deposit of Stock. As a condition precedent to the execution and delivery,
registration of transfer, split-up, combination, surrender or exchange of any
Receipt, the delivery of any distribution thereon or the withdrawal or deposit
of Stock, the Depositary, any of the Depositary's Agents or Patterson may
require any or all of the following: (i) payment to it of a sum sufficient for
the payment (or, in the event that the Depositary or Patterson shall have made
such payment, the reimbursement to it) of any tax or other governmental charge
with respect thereto (including any such tax or charge with respect to the Stock
being deposited or withdrawn or with respect to the

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*This section to be modified to reflect any restrictions on withdrawal of
underlying securities


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Common Stock or other securities or property of Patterson being issued upon
conversion or redemption); (ii) production of proof satisfactory to it as to the
identity and genuineness of any signature; and (iii) compliance with such
reasonable regulations, if any, as the Depositary or Patterson may establish not
inconsistent with the provisions of this Deposit Agreement. The deposit of Stock
may be refused, the delivery of Receipts against Stock or the registration of
transfer, split-up, combination, surrender or exchange of outstanding Receipts
and the withdrawal of deposited Stock may be suspended (i) during any period
when the register of stockholders of Patterson is closed, (ii) if any such
action is deemed necessary or advisable by the Depositary, any of the
Depositary's Agents or Patterson at any time or from time to time because of any
requirement of law or of any government or governmental body or commission, or
under any provision of this Deposit Agreement, or (iii) with the approval of
Patterson, for any other reason. Without limitation of the foregoing, the
Depositary shall not knowingly accept for deposit under this Deposit Agreement
any shares of Stock that are required to be registered under the Securities Act
unless a registration statement under the Securities Act is in effect as to such
shares of Stock.

         SECTION 2.8  Lost Receipts, etc. In case any Receipt shall be
mutilated or destroyed or lost or stolen, the Depositary shall execute and
deliver a Receipt of like form and tenor in exchange and substitution for such
mutilated Receipt or in lieu of and in substitution for such destroyed, lost or
stolen Receipt unless the Depositary has notice that such Receipt has been
acquired by a bona fide purchaser; provided, however, that the holder thereof
provides the Depositary with (i) evidence satisfactory to the Depositary of such
destruction, loss or theft of such Receipt, of the authenticity thereof and of
his ownership thereof, (ii) reasonable indemnification satisfactory to the
Depositary or the payment of any charges incurred by the Depositary in obtaining
insurance in lieu of such indemnification, and (iii) payment of any expense
(including fees, charges and expenses of the Depositary) in connection with such
execution and delivery.

         SECTION 2.9  Cancellation and Destruction of Surrendered Receipts.
All Receipts surrendered to the Depositary or any Depositary's Agent shall be
cancelled by the Depositary. Except as prohibited by applicable law or
regulation, the Depositary is authorized to destroy such Receipts so cancelled.

                                    ARTICLE 3
            CERTAIN OBLIGATIONS OF HOLDERS OF RECEIPTS AND PATTERSON

         SECTION 3.1  Filing Proofs, Certificates and Other Information.
Any person presenting Stock for deposit or any holder of a Receipt may be
required from time to time to file such proof of residence or other information,
to execute such certificates and to make such representations and warranties as
the Depositary or Patterson may reasonably deem necessary or proper. The
Depositary or Patterson may withhold or delay the delivery of any Receipt, the
registration of transfer, redemption, conversion or exchange of any Receipt, the
withdrawal of the Stock represented by the Depositary Shares evidenced by any
Receipt or the distribution of any dividend or other distribution until such
proof or other information is filed, such certificates are executed or such
representations and warranties are made.

         SECTION 3.2  Payment of Taxes or Other Governmental Charges. If
any tax or other governmental charge shall become payable by or on behalf of the
Depositary with respect to (i) any Receipt, (ii) the Depositary Shares evidenced
by such Receipt, (iii) the Stock (or fractional interest therein) or other
property represented by such Depositary Shares, or (iv) any transaction referred
to in Section 4.6, such tax (including transfer, issuance or acquisition taxes,
if any) or governmental charge shall be payable by the holder of such Receipt,
who shall pay the amount thereof to the Depositary. Until such payment is made,
registration of transfer of any Receipt or any split-up or combination thereof
or any withdrawal of the Stock or money or other property, if any, represented
by the Depositary Shares evidenced by such Receipt may be refused, any dividend
or other distribution may be withheld and any part or all of the Stock or other
property (including Common Stock or other securities received in


                                      D-7
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connection with a conversion or redemption of Stock) represented by the
Depositary Shares evidenced by such Receipt may be sold for the account of the
holder thereof (after attempting by reasonable means to notify such holder prior
to such sale). Any dividend or other distribution so withheld and the proceeds
of any such sale may be applied to any payment of such tax or other governmental
charge, the holder of such Receipt remaining liable for any deficiency.

         SECTION 3.3  Withholding. The Depositary shall act as the tax
withholding agent for any payments, distributions and exchanges made with
respect to the Depositary Shares and Receipts, and the Stock, Common Stock or
other securities or assets represented thereby (collectively, the "Securities").
The Depositary shall be responsible with respect to the Securities for the
timely (i) collection and deposit of any required withholding or backup
withholding tax, and (ii) filing of any information returns or other documents
with federal (and other applicable) taxing authorities.

         SECTION 3.4  Representations and Warranties as to Stock. In the
case of the initial deposit of the Stock, Patterson and, in the case of
subsequent deposits thereof, each person so depositing Stock under this Deposit
Agreement shall be deemed thereby to represent and warrant that such Stock and
each certificate therefor are valid and that the person making such deposit is
duly authorized to do so. Such representations and warranties shall survive the
deposit of the Stock and the issuance of Receipts therefor.

                                    ARTICLE 4
                               THE STOCK, NOTICES

         SECTION 4.1  Cash Distributions. Whenever the Depositary shall
receive any cash dividend or other cash distribution on the Stock, the
Depositary shall, subject to Section 3.2, distribute to record holders of
Receipts on the record date fixed pursuant to Section 4.4 such amounts of such
sum as are, as nearly as practicable, in proportion to the respective numbers of
Depositary Shares evidenced by the Receipts held by such holders; provided,
however, that in case Patterson or the Depositary shall be required by law to
withhold and does withhold from any cash dividend or other cash distribution in
respect of the Stock an amount on account of taxes, the amount made available
for distribution or distributed in respect of Depositary Shares shall be reduced
accordingly. The Depositary shall distribute or make available for distribution,
as the case may be, only such amount, however, as can be distributed without
attributing to any owner of Depositary Shares a fraction of one cent and any
balance not so distributable shall be held by the Depositary (without liability
for interest thereon) and shall be added to and be treated as part of the next
sum received by the Depositary for distribution to record holders of Receipts
then outstanding.

         SECTION 4.2  Distributions Other Than Cash. Whenever the
Depositary shall receive any distribution other than cash, rights, preferences
or privileges upon the Stock, the Depositary shall, subject to Section 3.2,
distribute to record holders of Receipts on the record date fixed pursuant to
Section 4.4 such amounts of the securities or property received by it as are, as
nearly as practicable, in proportion to the respective numbers of Depositary
Shares evidenced by the Receipts held by such holders, in any manner that the
Depositary and Patterson may deem equitable and practicable for accomplishing
such distribution. If, in the opinion of Patterson after consultation with the
Depositary, such distribution cannot be made proportionately among such record
holders, or if for any other reason (including any tax withholding or securities
law requirement), the Depositary deems, after consultation with Patterson, such
distribution not to be feasible, the Depositary may, with the approval of
Patterson which approval shall not be unreasonably withheld, adopt such method
as it deems equitable and practicable for the purpose of effecting such
distribution, including the sale (at public or private sale) of the securities
or property thus received, or any part thereof, at such place or places and upon
such terms as it may deem proper. The net proceeds of any such sale shall,
subject to Section 3.2, be distributed or made available for distribution, as


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the case may be, by the Depositary to record holders of Receipts as provided by
Section 4.1 in the case of a distribution received in cash.

         SECTION 4.3  Subscription Rights, Preferences or Privileges. If
Patterson shall at any time offer or cause to be offered to the persons in whose
names Stock is registered on the books of Patterson any rights, preferences or
privileges to subscribe for or to purchase any securities or any rights,
preferences or privileges of any other nature, such rights, preferences or
privileges shall in each such instance be made available by the Depositary to
the record holders of Receipts in such manner as Patterson shall instruct
(including by the issue to such record holders of warrants representing such
rights, preferences or privileges); provided, however, that (a) if at the time
of issue or offer of any such rights, preferences or privileges Patterson
determines and instructs the Depositary that it is not lawful or feasible to
make such rights, preferences or privileges available to some or all holders of
Receipts (by the issue of warrants or otherwise) or (b) if and to the extent
instructed by holders of Receipts who do not desire to exercise such rights,
preferences or privileges, the Depositary shall then, in each case, and if
applicable laws or the terms of such rights, preferences or privileges so
permit, sell such rights, preferences or privileges of such holders at public or
private sale, at such place or places and upon such terms as it may deem proper.
The net proceeds of any such sale shall be distributed by the Depositary to the
record holders of Receipts entitled thereto as provided by Section 4.1 in the
case of a distribution received in cash. If registration under the Securities
Act of the securities to which any rights, preferences or privileges relate is
required in order for holders of Receipts to be offered or sold such securities,
Patterson shall promptly file a registration statement pursuant to the
Securities Act with respect to such rights, preferences or privileges and
securities and use its best efforts and take all steps available to it to cause
such registration statement to become effective sufficiently in advance of the
expiration of such rights, preferences or privileges to enable such holders to
exercise such rights, preferences or privileges. In no event shall the
Depositary make available to the holders of Receipts any right, preference or
privilege to subscribe for or to purchase any securities unless and until such
registration statement shall have become effective or unless the offering and
sale of such securities to such holders are exempt from registration under the
provisions of the Securities Act. If any other action under the law of any
jurisdiction or any governmental or administrative authorization, consent or
permit is required in order for such rights, preferences or privileges to be
made available to holders of Receipts, Patterson agrees with the Depositary that
Patterson will use its reasonable best efforts to take such action or obtain
such authorization, consent or permit sufficiently in advance of the expiration
of such rights, preferences or privileges to enable such holders to exercise
such rights, preferences or privileges.

         SECTION 4.4  Notice of Dividends, Fixing of Record Date for
Holders of Receipts. Whenever (i) any cash dividend or other cash distribution
shall become payable, or any distribution other than cash shall be made, or any
rights, preferences or privileges shall at any time be offered, with respect to
the Stock, or (ii) the Depositary shall receive notice of any meeting at which
holders of Stock are entitled to vote or of which holders of Stock are entitled
to notice or of the mandatory conversion of, or any election on the part of
Patterson to call for the redemption of, any shares of Stock, the Depositary
shall in each such instance fix a record date (which shall be the same date as
the record date fixed by Patterson with respect to the Stock) for the
determination of the holders of Receipts (x) who shall be entitled to receive
such dividend, distribution, rights, preferences or privileges or the net
proceeds of the sale thereof, or (y) who shall be entitled to give instructions
for the exercise of voting rights at any such meeting or to receive notice of
such meeting or of such conversion or redemption.

         SECTION 4.5  Voting Rights. Upon receipt of notice of any meeting at
which the holders of Stock are entitled to vote, the Depositary shall, as soon
as practicable thereafter, mail to the record holders of Receipts a notice,
which shall be provided by Patterson and which shall contain (i) such
information as is contained in such notice of meeting, (ii) a statement that the
holders of Receipts at the close of business on a specified record date fixed
pursuant to Section 4.4 will be entitled, subject to any applicable


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provision of law, the Certificate of Incorporation or the Certificate of
Designation, to instruct the Depositary as to the exercise of the voting rights
pertaining to the Stock represented by their respective Depositary Shares and
(iii) a brief statement as to the manner in which such instructions may be
given. Upon the written request of a holder of a Receipt on such record date,
the Depositary shall endeavor insofar as practicable to vote or cause to be
voted the Stock represented by the Depositary Shares evidenced by such Receipt
in accordance with the instructions set forth in such request. Patterson hereby
agrees to take all reasonable action that may be deemed necessary by the
Depositary in order to enable the Depositary to vote such Stock or cause such
Stock to be voted. In the absence of specific instructions from the holder of a
Receipt, the Depositary will abstain from voting to the extent of the Stock
represented by the Depositary Shares evidenced by such Receipt.

         SECTION 4.6  Changes Affecting Stock and Reclassifications,
Recapitalizations, etc. Upon any split-up, consolidation or any other
reclassification of Stock, or upon any recapitalization, reorganization, merger,
amalgamation or consolidation affecting Patterson or to which it is a party
(other than a Merger or Consolidation) or sale of all or substantially all of
Patterson's assets, the Depositary shall treat any shares of stock or other
securities or property (including cash) that shall be received by the Depositary
in exchange for or upon conversion of or in respect of the Stock as new
deposited property under this Deposit Agreement, and Receipts then outstanding
shall thenceforth represent the proportionate interests of holders thereof in
the new deposited property so received in exchange for or upon conversion or in
respect of such Stock. In any such case the Depositary may, in its discretion,
with the approval of Patterson, execute and deliver additional Receipts, or may
call for the surrender of all outstanding Receipts to be exchanged for new
Receipts specifically describing such new deposited property.

         SECTION 4.7  Reports. The Depositary shall make available for
inspection by holders of Receipts at the Corporate Office, the New York Office
and at such other places as it may from time to time deem advisable during
normal business hours any reports and communications received from Patterson
that are received by the Depositary as the holder of Stock.

         SECTION 4.8  Lists of Receipt Holders. Promptly upon request from
time to time by Patterson, the Depositary shall furnish to it a list, as of a
recent date, of the names, addresses and holdings of Depositary Shares of all
persons in whose names Receipts are registered on the books of the Depositary.
At the expense of Patterson, Patterson shall have the right to inspect transfer
and registration records of the Depositary, any Depositary's Agent or the
Registrar, take copies thereof and require the Depositary, any Depositary's
Agent or the Registrar to supply copies of such portions of such records as
Patterson may request.

                                    ARTICLE 5
      THE DEPOSITARY, THE DEPOSITARY'S AGENTS, THE REGISTRAR AND PATTERSON

         SECTION 5.1  Maintenance of Offices, Agencies, Transfer Books by
the Depositary; the Registrar. Upon execution of this Deposit Agreement in
accordance with its terms, the Depositary shall maintain (i) at the New York
Office facilities for the execution and delivery, registration, registration of
transfer, surrender and exchange, split-up, combination, redemption and
conversion of Receipts and deposit and withdrawal of Stock and (ii) at the
Corporate Office and at the offices of the Depositary's Agents, if any,
facilities for the delivery, registration, registration of transfer, surrender
and exchange, split-up, combination, conversion and redemption of Receipts and
deposit and withdrawal of Stock, all in accordance with the provisions of this
Deposit Agreement. The Depositary shall keep books at the Corporate Office for
the registration and transfer of Receipts, which books at all reasonable times
shall be open for inspection by the record holders of Receipts; provided that
any such holder requesting to exercise such right shall certify to the
Depositary that such inspection shall be for a proper purpose reasonably related
to such person's interest as an owner of Depositary Shares. The Depositary shall


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consult with Patterson upon receipt of any request for inspection. The
Depositary may close such books, at any time or from time to time, when deemed
expedient by it in connection with the performance of its duties hereunder. If
the Receipts or the Depositary Shares evidenced thereby or the Stock represented
by such Depositary Shares shall be listed on one or more stock exchanges, the
Depositary shall, with the approval of Patterson, appoint a Registrar for
registry of such Receipts or Depositary Shares in accordance with the
requirements of such exchange or exchanges. Such Registrar (which may be the
Depositary if so permitted by the requirements of such exchange or exchanges)
may be removed and a substitute registrar appointed by the Depositary upon the
request or with the approval of Patterson. In addition, if the Receipts, such
Depositary Shares or such Stock are listed on one or more stock exchanges, the
Depositary will, at the request of Patterson, arrange such facilities for the
delivery, registration, registration of transfer, surrender and exchange,
split-up, combination, redemption or conversion of such Receipts, such
Depositary Shares or such Stock as may be required by law or applicable stock
exchange regulations.

         SECTION 5.2  Prevention or Delay in Performance by the Depositary,
the Depositary's Agents, the Registrar or Patterson. Neither the Depositary nor
any Depositary's Agent nor the Registrar nor Patterson shall incur any liability
to any holder of any Receipt, if by reason of any provision of any present or
future law or regulation thereunder of the United States of America or of any
other governmental authority or, in the case of the Depositary, the Registrar or
any Depositary's Agent, by reason of any provision, present or future, of the
Certificate of Incorporation or the Certificate of Designation or, in the case
of Patterson, the Depositary, the Registrar or any Depositary's Agent, by reason
of any act of God or war or other circumstances beyond the control of the
relevant party, the Depositary, any Depositary's Agent, the Registrar or
Patterson shall be prevented or forbidden from doing or performing any act or
thing that the terms of this Deposit Agreement provide shall be done or
performed; nor shall the Depositary, any Depositary's Agent, the Registrar or
Patterson incur any liability to any holder of a Receipt (i) by reason of any
nonperformance or delay, caused as aforesaid, in the performance of any act or
thing that the terms of this Deposit Agreement provide shall or may be done or
performed, or (ii) by reason of any exercise of, or failure to exercise, any
discretion provided for in this Deposit Agreement except, in the case of the
Depositary, any Depositary's Agent or the Registrar, if any such exercise or
failure to exercise discretion is caused by its negligence or bad faith.

         SECTION 5.3  Obligations of the Depositary, the Depositary's Agents,
the Registrar and Patterson. Patterson assumes no obligation and shall be
subject to no liability under this Deposit Agreement or the Receipts to holders
or other persons, except to perform in good faith such obligations as are
specifically set forth and undertaken by it to perform in this Deposit
Agreement. Each of the Depositary, the Depositary's Agents and the Registrar
assumes no obligation and shall be subject to no liability under this Deposit
Agreement or the Receipts to holders or other persons, except to perform such
obligations as are specifically set forth and undertaken by it to perform in
this Deposit Agreement without negligence or bad faith. Neither the Depositary
nor any Depositary's Agent nor the Registrar nor Patterson shall be under any
obligation to appear in, prosecute or defend any action, suit or other
proceeding with respect to Stock, Depositary Shares, Receipts or Common Stock
that in its opinion may involve it in expense or liability, unless indemnity
satisfactory to it against all expense and liability be furnished as often as
may be required. Neither the Depositary nor any Depositary's Agent nor the
Registrar nor Patterson shall be liable for any action or any failure to act by
it in reliance upon the advice of or information from legal counsel,
accountants, any person presenting Stock for deposit, any holder of a Receipt or
any other person believed by it in good faith to be competent to give such
advice or information. The Depositary, any Depositary's Agent, the Registrar and
Patterson may each rely and shall each be protected in acting upon any written
notice, request, direction or other document believed by it to be genuine and to
have been signed or presented by the proper party or parties. The Depositary,
the Registrar and any Depositary's Agent may own and deal in any class of
securities of Patterson and its affiliates and in Receipts or Depositary Shares.
The Depositary may also act as transfer agent or registrar


                                      D-11
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of any of the securities of Patterson and its affiliates. It is intended that
neither the Depositary nor any Depositary's Agent shall be deemed to be an
"issuer" of the Stock, the Depositary Shares, the Receipts or the Common Stock
issued upon conversion or redemption of the Stock under the federal securities
laws or applicable state securities laws, it being expressly understood and
agreed that the Depositary and any Depositary's Agent are acting only in a
ministerial capacity as Depositary for the Stock; provided, however, that the
Depositary agrees to comply with all information reporting and withholding
requirements applicable to it under law or this Deposit Agreement in its
capacity as Depositary. Neither the Depositary (or its officers, directors,
employees or agents) nor any Depositary's Agent makes any representation or has
any responsibility as to the validity of the Registration Statement pursuant to
which the Depositary Shares are registered under the Securities Act, the Stock,
the Depositary Shares or any instruments referred to therein or herein, or as to
the correctness of any statement made therein or herein; provided, however, that
the Depositary is responsible for its representations in this Deposit Agreement.
The Depositary assumes no responsibility for the correctness of the description
that appears in the Receipts, which can be taken as a statement of Patterson
summarizing certain provisions of this Deposit Agreement. Notwithstanding any
other provision herein or in the Receipts, the Depositary makes no warranties or
representations as to the validity, genuineness or sufficiency of any Stock at
any time deposited with the Depositary hereunder or of the Depositary Shares, as
to the validity or sufficiency of this Deposit Agreement, as to the value of the
Depositary Shares or as to any right, title or interest of the record holders of
Receipts in and to the Depositary Shares except that the Depositary hereby
represents and warrants as follows: (i) the Depositary has been duly organized
and is validly existing and in good standing under the laws of the State of
[____________], with full power, authority and legal right under such law to
execute, deliver and carry out the terms of this Deposit Agreement; (ii) this
Deposit Agreement has been duly authorized, executed and delivered by the
Depositary; and (iii) this Deposit Agreement constitutes a valid and binding
obligation of the Depositary, enforceable against the Depositary in accordance
with its terms, except as enforcement thereof may be limited by bankruptcy,
insolvency, reorganization or other similar laws affecting enforcement of
creditors' rights generally and except as enforcement thereof is subject to
general principles of equity (regardless of whether enforcement is considered in
a proceeding in equity or at law). The Depositary shall not be accountable for
the use or application by Patterson of the Depositary Shares or the Receipts or
the proceeds thereof.

         SECTION 5.4  Resignation and Removal of the Depositary, Appointment of
Successor Depositary. The Depositary may at any time resign as Depositary
hereunder by written notice via registered mail of its election to do so
delivered to Patterson, such resignation to take effect upon the appointment of
a successor depositary and its acceptance of such appointment as hereinafter
provided. The Depositary may at any time be removed by Patterson by written
notice of such removal delivered to the Depositary, such removal to take effect
upon the appointment of a successor depositary and its acceptance of such
appointment as hereinafter provided. In case at any time the Depositary acting
hereunder shall resign or be removed, Patterson shall, within 45 days after the
delivery of the notice of resignation or removal, as the case may be, appoint a
successor depositary, which shall be a bank or trust company, or an affiliate of
a bank or trust company, having its principal office in the United States of
America and having a combined capital and surplus of at least $50,000,000. If a
successor depositary shall not have been appointed in 45 days, the resigning or
removed Depositary may petition a court of competent jurisdiction to appoint a
successor depositary. Every successor depositary shall execute and deliver to
its predecessor and to Patterson an instrument in writing accepting its
appointment hereunder, and thereupon such successor depositary, without any
further act or deed, shall become fully vested with all the rights, powers,
duties and obligations of its predecessor and for all purposes shall be the
Depositary under this Deposit Agreement, and such predecessor, upon payment of
all sums due it and on the written request of Patterson, shall promptly execute
and deliver an instrument transferring to such successor all rights and powers
of such predecessor hereunder, shall duly assign, transfer and deliver all
rights, title and interest in the Stock and any moneys or property held
hereunder to such successor and shall deliver to such successor a list of the
record holders of all outstanding Receipts. Any successor depositary shall


                                      D-12
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promptly mail notice of its appointment to the record holders of Receipts. Any
corporation into or with which the Depositary may be merged, consolidated or
converted shall be the successor of such Depositary without the execution or
filing of any document or any further act. Such successor depositary may execute
the Receipts either in the name of the predecessor depositary or in the name of
the successor depositary.

         SECTION 5.5  Corporate Notices and Reports. Patterson agrees that
it will deliver to the Depositary, and the Depositary will, promptly after
receipt thereof, transmit to the record holders of Receipts, in each case at the
address recorded in the Depositary's books, copies of all notices and reports
(including financial statements) required by law, by the rules of any national
securities exchange upon which the Stock, the Depositary Shares or the Receipts
are listed or by the Certificate of Incorporation and the Certificate of
Designation to be furnished by Patterson to holders of Stock. Such transmission
will be at Patterson's expense and Patterson will provide the Depositary with
such number of copies of such documents as the Depositary may reasonably
request. In addition, the Depositary will transmit to the record holders of
Receipts at Patterson's expense such other documents as may be requested by
Patterson.

         SECTION 5.6  Deposit of Stock by Patterson. Patterson agrees with
the Depositary that neither Patterson nor any company controlled by Patterson
will at any time deposit any Stock if such Stock is required to be registered
under the provisions of the Securities Act and no registration statement is at
such time in effect as to such Stock.

         SECTION 5.7  Indemnification by Patterson. Patterson agrees to
indemnify the Depositary, any Depositary's Agent and any Registrar against, and
hold each of them harmless from, any liability, costs and expenses (including
reasonable fees and expenses of counsel) that may arise out of or in connection
with its acting as Depositary, Depositary's Agent or Registrar, respectively,
under this Deposit Agreement and the Receipts, except for any liability arising
out of negligence, bad faith or willful misconduct on the part of any such
person or persons.

         SECTION 5.8  Fees, Charges and Expenses. No fees, charges and
expenses of the Depositary or any Depositary's Agent hereunder or of any
Registrar shall be payable by any person other than Patterson, except for any
taxes and other governmental charges and except as provided in this Deposit
Agreement. If, at the request of a holder of a Receipt, the Depositary incurs
fees, charges or expenses for which it is not otherwise liable hereunder, such
holder or other person will be liable for such fees, charges and expenses. All
other fees, charges and expenses of the Depositary and any Depositary's Agent
hereunder and of any Registrar (including, in each case, reasonable fees and
expenses of counsel) incident to the performance of their respective obligations
hereunder will be paid from time to time upon consultation and agreement between
the Depositary and Patterson as to the amount and nature of such fees, charges
and expenses.

                                    ARTICLE 6
                            AMENDMENT AND TERMINATION

         SECTION 6.1  Amendment. The form of the Receipts and any provision
of this Deposit Agreement may at any time and from time to time be amended by
agreement between Patterson and the Depositary in any respect that they may deem
necessary or desirable. Any amendment that shall impose or increase any fees,
taxes or charges payable by holders of Receipts (other than taxes and other
governmental charges, fees and other expenses payable by holders pursuant to the
terms hereof or of the Receipts), or that shall otherwise prejudice any
substantial existing right of holders of Receipts, shall not become effective as
to outstanding Receipts until the expiration of 90 days after notice of such
amendment shall have been given to the record holders of outstanding Receipts.
Every holder of an outstanding Receipt at the time any such amendment becomes
effective shall be deemed, by continuing to


                                      D-13
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hold such Receipt, to consent and agree to such amendment and to be bound by
this Deposit Agreement as amended thereby. In no event shall any amendment
impair the right, subject to the provisions of Sections 2.3, 2.6 and 2.7 and
Article 3, of any owner of any Depositary Shares to surrender the Receipt
evidencing such Depositary Shares with instructions to the Depositary to deliver
to the holder the Stock and all money and other property, if any, represented
thereby, except in order to comply with mandatory provisions of applicable law.

         SECTION 6.2  Termination. Whenever so directed by Patterson, the
Depositary will terminate this Deposit Agreement by mailing notice of such
termination to the record holders of all Receipts then outstanding at least 30
days prior to the date fixed in such notice for such termination. The Depositary
may likewise terminate this Deposit Agreement if at any time 45 days shall have
expired after the Depositary shall have delivered to Patterson a written notice
of its election to resign and a successor depositary shall not have been
appointed and accepted its appointment as provided in Section 5.4. If any
Receipts shall remain outstanding after the date of termination of this Deposit
Agreement, the Depositary thereafter shall discontinue the transfer of Receipts,
shall suspend the distribution of dividends to the holders thereof and shall not
give any further notices (other than notice of such termination) or perform any
further acts under this Deposit Agreement, except as provided below and that the
Depositary shall continue to collect dividends and other distributions
pertaining to Stock, shall sell rights, preferences or privileges as provided in
this Deposit Agreement and shall continue to deliver the Stock and any money and
other property represented by Receipts, without liability for interest thereon,
upon surrender thereof by the holders thereof. At any time after the expiration
of two years from the date of termination, the Depositary may sell Stock then
held hereunder at public or private sale, at such places and upon such terms as
it deems proper and may thereafter hold in a segregated account the net proceeds
of any such sale, together with any money and other property held by it
hereunder, without liability for interest, for the benefit, pro rata in
accordance with their holdings, of the holders of Receipts that have not
heretofore been surrendered. After making such sale, the Depositary shall be
discharged from all obligations under this Deposit Agreement except to account
for such net proceeds and money and other property. Upon the termination of this
Deposit Agreement, Patterson shall be discharged from all obligations under this
Deposit Agreement except for its obligations to the Depositary, any Depositary's
Agent and any Registrar under Sections 5.7 and 5.8. In the event this Deposit
Agreement is terminated, Patterson hereby agrees to use its best efforts to list
the underlying Stock on the Nasdaq National Market.

                                   ARTICLE 7
                                  MISCELLANEOUS

         SECTION 7.1  Counterparts. This Deposit Agreement may be executed
by Patterson and the Depositary in separate counterparts, each of which
counterparts, when so executed and delivered, shall be deemed an original, but
all such counterparts taken together shall constitute one and the same
instrument. Delivery of an executed counterpart of a signature page to this
Deposit Agreement by telecopier shall be effective as delivery of a manually
executed counterpart of this Deposit Agreement. Copies of this Deposit Agreement
shall be filed with the Depositary and the Depositary's Agents and shall be open
to inspection during business hours at the Corporate Office and the New York
Office and the respective offices of the Depositary's Agents, if any, by any
holder of a Receipt.

         SECTION 7.2  Exclusive Benefits of Parties. This Deposit Agreement
is for the exclusive benefit of the parties hereto, and their respective
successors hereunder, and shall not be deemed to give any legal or equitable
right, remedy or claim to any other person whatsoever.

         SECTION 7.3  Invalidity of Provisions. In case any one or more of
the provisions contained in this Deposit Agreement or in the Receipts should be
or become invalid, illegal or unenforceable in any


                                      D-14
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respect, the validity, legality and enforceability of the remaining provisions
contained herein or therein shall in no way be affected, prejudiced or disturbed
thereby.

         SECTION 7.4  Notices. Any notices to be given to Patterson
hereunder or under the Receipts shall be in writing and shall be deemed to have
been duly given if personally delivered or sent by mail, or by telegram or telex
or telecopier confirmed by letter, addressed to Patterson at 4510 Lamesa
Highway, P.O. Box 1416, Snyder, Texas 79550, Attention: Chief Executive Officer,
or at any other place to which Patterson may have transferred its principal
executive office. Any notices to be given to the Depositary hereunder or under
the Receipts shall be in writing and shall be deemed to have been duly given if
personally delivered or sent by mail, or by telegram or telex or telecopier
confirmed by letter, addressed to the Depositary at the Corporate Office. Any
notices given to any record holder of a Receipt hereunder or under the Receipts
shall be in writing and shall be deemed to have been duly given if personally
delivered or sent by mail, or by telegram or telex or telecopier confirmed by
letter, addressed to such record holder at the address of such record holder as
it appears on the books of the Depositary or, if such holder shall have filed
with the Depositary a written request that notices intended for such holder be
mailed to some other address, at the address designated in such request.
Delivery of a notice sent by mail, or by telegram or telex or telecopier shall
be deemed to be effected at the time when a duly addressed letter containing the
same (or a duly addressed letter confirming an earlier notice in the case of a
telegram or telex or telecopier message) is deposited, postage prepaid, in a
post office letter box. The Depositary or Patterson may, however, act upon any
telegram or telex or telecopier message received by it from the other or from
any holder of a Receipt, notwithstanding that such telegram or telex or
telecopier message shall not subsequently be confirmed by letter as aforesaid.

         SECTION 7.5  Depositary's Agents. The Depositary may, with the
approval of Patterson which approval shall not be unreasonably withheld, from
time to time appoint one or more Depositary's Agents to act in any respect for
the Depositary for the purposes of this Deposit Agreement and may vary or
terminate the appointment of such Depositary's Agents.

         SECTION 7.6  Holders of Receipts Are Parties. Notwithstanding that
holders of Receipts have not executed and delivered this Deposit Agreement or
any counterpart thereof, the holders of Receipts from time to time shall be
deemed to be parties to this Deposit Agreement and shall be bound by all of the
terms and conditions, and be entitled to all of the benefits, hereof and of the
Receipts by acceptance of delivery of Receipts.

         SECTION 7.7  Law. This Deposit Agreement and the Receipts and all
rights hereunder and thereunder and provisions hereof and thereof shall be
governed by, and construed in accordance with, the law of the State of New York
without giving effect to principles of conflict of laws.

         SECTION 7.8  Headings. The headings of articles and sections in
this Deposit Agreement and in the form of the Receipt set forth in Exhibit A
hereto have been inserted for convenience only and are not to be regarded as a
part of this Deposit Agreement or to have any bearing upon the meaning or
interpretation of any provision contained herein or in the Receipts.


                                      D-15
   19


         IN WITNESS WHEREOF, Patterson Energy and [_______________________] have
duly executed this Deposit Agreement as of the day and year first above set
forth and all holders of Receipts shall become parties hereto by and upon
acceptance by them of delivery of Receipts issued in accordance with the terms
hereof.

                                           PATTERSON ENERGY, INC.


Attest:
                                           By
                                             ----------------------------------
- ----------------------------------           Cloyce A. Talbott,
                                             Chief Executive Officer


                                          [                                   ]
                                           -----------------------------------



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




                                      D-16
   20


                                                                      EXHIBIT A


                               DEPOSITARY RECEIPT
                                       FOR
                                DEPOSITARY SHARES
                       EACH REPRESENTING [ ] OF A SHARE OF
                [                                              ]
                 ----------------------------------------------

                                 PREFERRED STOCK
                                       OF
                             PATTERSON ENERGY, INC.
             (Incorporated under the Laws of the State of Delaware)

No.

         [_________________________________] (the "Depositary") hereby certifies
that ____________ is the registered owner of ___________ Depositary Shares (the
"Depositary Shares"), each Depositary Share representing [ ] of a share of
[____________________________] Preferred Stock, $.01 par value (the "Stock"), of
Patterson Energy, Inc., a corporation duly organized and existing under the laws
of the State of Delaware ("Patterson"), and the same proportionate interest in
any and all other property received by the Depositary in respect of such shares
of Stock and held by the Depositary under the Deposit Agreement (as defined
below). Subject to the terms of the Deposit Agreement, each owner of a
Depositary Share is entitled, proportionately, to all the rights, preferences
and privileges of the Stock represented thereby, including the dividend, voting,
liquidation and other rights contained in the Certificate of Designation
establishing the rights, preferences, privileges and limitations of the Stock
(the "Certificate of Designation"), copies of which are on file at the office of
the Depositary at which at any particular time its business in respect of
matters governed by the Deposit Agreement shall be administered, which at the
time of the execution of the Deposit Agreement is located at [________________]
(the "Corporate Office").

         This Depositary Receipt ("Receipt") shall not be entitled to any
benefits under the Deposit Agreement or be valid or obligatory for any purpose
unless this Receipt shall have been executed manually or, if a Registrar for the
Receipts (other than the Depositary) shall have been appointed, by facsimile by
the Depositary by the signature of a duly authorized signatory and, if executed
by facsimile signature of the Depositary, shall have been countersigned manually
by such Registrar by the signature of a duly authorized signatory.

THE DEPOSITARY IS NOT RESPONSIBLE FOR THE VALIDITY OF ANY DEPOSITED STOCK. THE
DEPOSITARY ASSUMES NO RESPONSIBILITY FOR THE CORRECTNESS OF THE DESCRIPTION SET
FORTH IN THIS RECEIPT, WHICH CAN BE TAKEN AS A STATEMENT OF PATTERSON
SUMMARIZING CERTAIN PROVISIONS OF THE DEPOSIT AGREEMENT. UNLESS EXPRESSLY SET
FORTH IN THE DEPOSIT AGREEMENT, THE DEPOSITARY MAKES NO WARRANTIES OR
REPRESENTATIONS AS TO THE VALIDITY, GENUINENESS OR SUFFICIENCY OF ANY STOCK AT
ANY TIME DEPOSITED WITH THE DEPOSITARY UNDER THE DEPOSIT AGREEMENT OR OF THE
DEPOSITARY SHARES, AS TO THE VALIDITY OR SUFFICIENCY OF THE DEPOSIT AGREEMENT,
AS TO THE VALUE OF THE DEPOSITARY SHARES OR AS TO ANY RIGHT, TITLE OR INTEREST
OF THE RECORD HOLDERS OF THE DEPOSITARY RECEIPTS IN AND TO THE DEPOSITARY
SHARES.

         Patterson will furnish to any holder of this Receipt without charge,
upon request addressed to its executive office, a full statement of the
designation, relative rights, preferences and limitations of the shares of each
authorized class, and of each class of preferred stock authorized to be issued,
so far as the


                                      D-17
   21


same may have been fixed, and a statement of the authority of the Board of
Directors of Patterson to designate and fix the relative rights, preferences and
limitations of other classes.

         This Receipt is continued on the reverse hereof and the additional
provisions therein set forth for all purposes have the same effect as if set
forth at this place.

Dated:                            [                                           ]
                                   -------------------------------------------
                                   as Depositary and Registrar



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


                                      D-18
   22


                     [FORM OF REVERSE OF DEPOSITARY RECEIPT]

         (1) The Deposit Agreement. Depositary Receipts (the "Receipts"), of
which this Receipt is one, are made available upon the terms and conditions set
forth in the Deposit Agreement, dated as of [_________] (the "Deposit
Agreement"), among Patterson, the Depositary and all holders from time to time
of Receipts. The Deposit Agreement (copies of which are on file at the Corporate
Office, the office maintained by the Depositary in the Borough of Manhattan, the
City of New York which at the time of the execution of the Deposit Agreement is
located at [________________________] (the "New York Office") and at the office
of any agent of the Depositary) sets forth the rights of holders of Receipts and
the rights and duties of the Depositary. The statements made on the face and the
reverse of this Receipt are summaries of certain provisions of the Deposit
Agreement and are subject to the detailed provisions thereof, to which reference
is hereby made. In the event of any conflict between the provisions of this
Receipt and the provisions of the Deposit Agreement, the provisions of the
Deposit Agreement will govern.

         (2) Definitions. Unless otherwise expressly herein provided, all
defined terms used herein shall have the meanings ascribed thereto in the
Deposit Agreement.

         (3) Redemption and Conversion of Stock.* Whenever Patterson shall elect
to redeem or be required to convert shares of Stock into shares of Common Stock
in accordance with the Certificate of Designation, it shall (unless otherwise
agreed in writing with the Depositary) give the Depositary in its capacity as
Depositary not less than 5 business days' prior notice of the proposed date of
the mailing of a notice of redemption or conversion of Stock and the
simultaneous redemption or conversion of the Depositary Shares representing the
Stock to be redeemed or converted and of the number of such shares of Stock held
by the Depositary to be redeemed or converted. The Depositary shall, as directed
by Patterson in writing, mail, first class postage prepaid, notice of the
redemption or conversion of Stock and the proposed simultaneous redemption or
conversion of Depositary Shares representing the Stock to be redeemed or
converted, not less than 30 and not more than 60 days prior to the date fixed
for redemption or conversion of such Stock and Depositary Shares, to the record
holders of the Receipts evidencing the Depositary Shares to be so redeemed or
converted, at the addresses of such holders as the same appear on the records of
the Depositary; provided, that if the effectiveness of a Merger or Consolidation
(as defined in the Certificate of Designation) makes it impracticable to provide
at least 30 days' notice, the Depositary shall provide such notice as soon as
practicable prior to such effectiveness. Any such notice shall also be published
in the same manner as notices of redemption or conversion of the Stock are
required to be published pursuant to Section [ ] of the Certificate of
Designation. On the date of any such redemption or conversion, the Depositary
shall surrender the certificate or certificates held by the Depositary
evidencing the number of shares of Stock to be redeemed or converted in the
manner specified in the notice of redemption or conversion of Stock provided by
Patterson pursuant to Section [ ] of the Certificate of Designation. The
Depositary shall, thereafter, redeem or convert the number of Depositary Shares
representing such redeemed or converted Stock upon the surrender of Receipts
evidencing such Depositary Shares in the manner provided in the notice sent to
record holders of Receipts; provided, that the Depositary shall have received,
upon surrendering such certificate or certificates as aforesaid, a sufficient
number of shares of Common Stock or other securities to convert or redeem such
number of Depositary Shares (including, in the event that Patterson elects
pursuant to Section [ ] of the Certificate of Designation to exercise any option
to deliver shares of Common Stock or other securities in lieu of any cash
consideration payable on the Effective Date (as defined in the Certificate of
Designation) of any Merger or Consolidation, a number of shares of Common Stock
or other securities equal to such cash consideration (as determined in the
manner set forth in the Certificate of Designation)), plus any accrued and
unpaid dividends payable with respect thereto to and including the date of any
such redemption or

- ---------------------------------
*This section to be modified to discuss specific redemption or conversion terms
of the Stock, if any.


                                      D-19
   23


conversion and any other cash consideration payable on the Effective Date of a
Merger or Consolidation (other than any dividends or other cash consideration
payable on the Effective Date of a Merger or Consolidation that Patterson has
elected to pay in shares of Common Stock or other securities pursuant to Section
[ ] of the Certificate of Designation). In case fewer than all the outstanding
Depositary Shares are to be redeemed, the Depositary Shares to be redeemed shall
be selected by the Depositary by lot or on a pro rata basis. Notice having been
mailed and published as aforesaid, from and after the redemption or conversion
date (unless Patterson shall have failed to redeem or convert the shares of
Stock to be redeemed or converted by it upon the surrender of the certificate or
certificates therefor by the Depositary as described above), the Depositary
Shares called for redemption or subject to conversion shall be deemed no longer
to be outstanding and all rights of the holders of Receipts evidencing such
Depositary Shares (except the right to receive the shares of Common Stock or
other securities and cash, if any, payable upon redemption or conversion upon
surrender of such Receipts) shall, to the extent of such Depositary Shares,
cease and terminate. Upon surrender in accordance with said notice of the
Receipts evidencing such Depositary Shares (properly endorsed or assigned for
transfer, if the Depositary shall so require), such Depositary Shares shall be
converted into or redeemed for shares of Common Stock or other securities at a
rate equal to [ ] of the number of shares of Common Stock or other securities
delivered, and the holders thereof shall be entitled to [________] of the cash,
if any, payable, in respect of the shares of Stock pursuant to the Certificate
of Designation. The foregoing is subject further to the terms and conditions of
the Certificate of Designation. If fewer than all of the Depositary Shares
evidenced by this Receipt are called for redemption, the Depositary will deliver
to the holder of this Receipt upon its surrender to the Depositary, together
with shares of Common Stock or other securities and all accrued and unpaid
dividends to and including the date fixed for redemption payable in respect of
the Depositary Shares called for redemption, a new Receipt evidencing the
Depositary Shares evidenced by such prior Receipt and not called for redemption.

         (4) Surrender of Receipts and Withdrawal of Stock. Upon surrender of
this Receipt to the Depositary at the Corporate Office, the New York Office or
at such other offices as the Depositary may designate, and subject to the
provisions of the Deposit Agreement, the holder hereof is entitled to withdraw,
and to obtain delivery, without unreasonable delay, to or upon the order of such
holder, any or all of the Stock (but only in whole shares of Stock) and all
money and other property, if any, at the time represented by the Depositary
Shares evidenced by this Receipt; provided, however, that, in the event this
Receipt shall evidence a number of Depositary Shares in excess of the number of
Depositary Shares representing the whole number of shares of Stock to be
withdrawn, the Depositary shall, in addition to such whole number of shares of
Stock and such money and other property, if any, to be withdrawn, deliver, to or
upon the order of such holder, a new Receipt or Receipts evidencing such excess
number of whole Depositary Shares.

         (5) Transfers, Split-ups, Combinations. Subject to Paragraphs 6, 7 and
8 below, this Receipt is transferable on the books of the Depositary upon
surrender of this Receipt to the Depositary at the Corporate Office or the New
York Office, or at such other offices as the Depositary may designate, properly
endorsed or accompanied by a properly executed instrument of transfer, and upon
such transfer the Depositary shall sign and deliver a Receipt or Receipts to or
upon the order of the person entitled thereto, all as provided in and subject to
the Deposit Agreement. This Receipt may be split into other Receipts or combined
with other Receipts into one Receipt evidencing the same aggregate number of
Depositary Shares evidenced by the Receipt or Receipts surrendered; provided,
however, that the Depositary shall not issue any Receipt evidencing a fractional
Depositary Share.

         (6) Conditions to Signing and Delivery, Transfer, etc., of Receipts.
Prior to the execution and delivery, registration of transfer, split-up,
combination, surrender or exchange of this Receipt, the delivery of any
distribution hereon or the withdrawal or deposit of Stock, the Depositary, any
of the Depositary's Agents or Patterson may require any or all of the following:
(i) payment to it of a sum sufficient for the


                                      D-20
   24


payment (or, in the event that the Depositary or Patterson shall have made such
payment, the reimbursement to it) of any tax or other governmental charge with
respect thereto (including any such tax or charge with respect to Stock being
deposited or withdrawn or with respect to Common Stock or other securities or
property of Patterson being issued upon conversion or redemption); (ii)
production of proof satisfactory to it as to the identity and genuineness of any
signature; and (iii) compliance with such reasonable regulations, if any, as the
Depositary or Patterson may establish not inconsistent with the Deposit
Agreement. Any person presenting Stock for deposit, or any holder of this
Receipt, may be required to file such proof of information, to execute such
certificates and to make such representations and warranties as the Depositary
or Patterson may reasonably deem necessary or proper. The Depositary or
Patterson may withhold or delay the delivery of this Receipt, the registration
of transfer, redemption, conversion or exchange of this Receipt, the withdrawal
of the Stock represented by the Depositary Shares evidenced by this Receipt or
the distribution of any dividend or other distribution until such proof or other
information is filed, such certificates are executed or such representations and
warranties are made.

         (7) Suspension of Delivery, Transfer, etc. The deposit of Stock may be
refused and the delivery of this Receipt against Stock or the registration of
transfer, split-up, combination, surrender or exchange of this Receipt and the
withdrawal of deposited Stock may be suspended (i) during any period when the
register of stockholders of Patterson is closed, (ii) if any such action is
deemed necessary or advisable by the Depositary, any of the Depositary's Agents
or Patterson at any time or from time to time because of any requirement of law
or of any government or governmental body or commission, or under any provision
of the Deposit Agreement, or (iii) with the approval of Patterson, for any other
reason. The Depositary shall not be required (a) to issue, transfer or exchange
any Receipts for a period beginning at the opening of business 15 days next
preceding any selection of Depositary Shares and Stock to be redeemed and ending
at the close of business on the day of the mailing of notice of redemption of
Depositary Shares or (b) to transfer or exchange for another Receipt any Receipt
evidencing Depositary Shares called or being called for redemption, in whole or
in part, or subject to conversion except as provided in the last sentence of
Paragraph 3.

         (8) Payment of Taxes or Other Governmental Charges. If any tax or other
governmental charge shall become payable by or on behalf of the Depositary with
respect to (i) this Receipt, (ii) the Depositary Shares evidenced by this
Receipt, (iii) the Stock (or fractional interest therein) or other property
represented by such Depositary Shares, or (iv) any transaction referred to in
Section 4.6 of the Deposit Agreement, such tax (including transfer, issuance or
acquisition taxes, if any) or governmental charge shall be payable by the holder
of this Receipt, who shall pay the amount thereof to the Depositary. Until such
payment is made, registration of transfer of this Receipt or any split-up or
combination hereof or any withdrawal of the Stock or money or other property, if
any, represented by the Depositary Shares evidenced by this Receipt may be
refused, any dividend or other distribution may be withheld and any part or all
of the Stock or other property (including Common Stock or other securities
received in connection with a conversion or redemption of Stock) represented by
the Depositary Shares evidenced by this Receipt may be sold for the account of
the holder hereof (after attempting by reasonable means to notify such holder
prior to such sale). Any dividend or other distribution so withheld and the
proceeds of any such sale may be applied to any payment of such tax or other
governmental charge, the holder of this Receipt remaining liable for any
deficiency.

         (9) Amendment. The form of the Receipts and any provision of the
Deposit Agreement may at any time and from time to time be amended by agreement
between Patterson and the Depositary in any respect that they may deem necessary
or desirable. Any amendment that shall impose or increase any fees, taxes or
charges payable by holders of Receipts (other than taxes and other governmental
charges, fees and other expenses payable by holders as provided herein or in the
Deposit Agreement), or that shall otherwise prejudice any substantial existing
right of holders of Receipts, shall not become effective as to outstanding
Receipts until the expiration of 90 days after notice of such amendment shall
have been given


                                      D-21
   25


to the record holders of outstanding Receipts. The holder of this Receipt at the
time any such amendment becomes effective shall be deemed, by continuing to hold
this Receipt, to consent and agree to such amendment and to be bound by the
Deposit Agreement as amended thereby. In no event shall any amendment impair the
right, subject to the provisions of Paragraphs 3, 4, 6, 7 and 8 hereof and of
Sections 2.3, 2.6 and 2.7 and Article 3 of the Deposit Agreement, of the owner
of the Depositary Shares evidenced by this Receipt to surrender this Receipt
with instructions to the Depositary to deliver to the holder the Stock and all
money and other property, if any, represented thereby, except in order to comply
with mandatory provisions of applicable law.

         (10) Fees, Charges and Expenses. Patterson will pay all fees, charges
and expenses of the Depositary, except for taxes (including transfer taxes, if
any) and other governmental charges and such charges as are expressly provided
in the Deposit Agreement to be at the expense of persons depositing Stock,
holders of Receipts or other persons.

         (11) Title to Receipts. It is a condition of this Receipt, and every
successive holder hereof by accepting or holding the same consents and agrees,
that title to this Receipt (and to the Depositary Shares evidenced hereby), when
properly endorsed or accompanied by a properly executed instrument of transfer,
is transferable by delivery with the same effect as in the case of a negotiable
instrument; provided, however, that the Depositary may, notwithstanding any
notice to the contrary, treat the record holder hereof at such time as the
absolute owner hereof for the purpose of determining the person entitled to
distribution of dividends or other distributions or to any notice provided for
in the Deposit Agreement and for all other purposes.

         (12) Dividends and Distributions. Whenever the Depositary shall receive
any cash dividend or other cash distribution on the Stock, the Depositary shall,
subject to the provisions of the Deposit Agreement, distribute to record holders
of Receipts such amounts of such sums as are, as nearly as practicable, in
proportion to the respective numbers of Depositary Shares evidenced by the
Receipts held by such holders; provided, however, that in case Patterson or the
Depositary shall be required by law to withhold and does withhold from any cash
dividend or other cash distribution in respect of the Stock an amount on account
of taxes, the amount made available for distribution or distributed in respect
of Depositary Shares shall be reduced accordingly. The Depositary shall
distribute or make available for distribution, as the case may be, only such
amount, however, as can be distributed without attributing to any owner of
Depositary Shares a fraction of one cent and any balance not so distributable
shall be held by the Depositary (without liability for interest thereon) and
shall be added to and be treated as part of the next sum received by the
Depositary for distribution to record holders of Receipts then outstanding.

         (13) Subscription Rights, Preferences or Privileges. If Patterson shall
at any time offer or cause to be offered to the persons in whose name Stock is
registered on the books of Patterson any rights, preferences or privileges to
subscribe for or to purchase any securities or any rights, preferences or
privileges of any other nature, such rights, preferences or privileges shall in
each such instance, subject to the provisions of the Deposit Agreement, be made
available by the Depositary to the record holders of Receipts in such manner as
Patterson shall instruct.

         (14) Notice of Dividends, Fixing of Record Date. Whenever (i) any cash
dividend or other cash distribution shall become payable, or any distribution
other than cash shall be made, or any rights, preferences or privileges shall at
any time be offered, with respect to the Stock, or (ii) the Depositary shall
receive notice of any meeting at which holders of Stock are entitled to vote or
of which holders of Stock are entitled to notice or of the mandatory conversion
of, or any election on the part of Patterson to call for redemption of, any
shares of Stock, the Depositary shall in each such instance fix a record date
(which shall be the same date as the record date fixed by Patterson with respect
to the Stock) for the determination of the holders of Receipts (x) who shall be
entitled to receive such dividend, distribution,


                                      D-22
   26


rights, preferences or privileges or the net proceeds of the sale thereof, or
(y) who shall be entitled to give instructions for the exercise of voting rights
at any such meeting or of such meeting or to receive notice of such conversion
or redemption.

         (15) Voting Rights. Upon receipt of notice of any meeting at which the
holders of Stock are entitled to vote, the Depositary shall, as soon as
practicable thereafter, mail to the record holders of Receipts a notice, which
shall contain (i) such information as is contained in such notice of meeting,
(ii) a statement that the holders of Receipts at the close of business on a
specified record date determined as provided in Paragraph 14 will be entitled,
subject to any applicable provision of law, the Certificate of Incorporation or
the Certificate of Designation, to instruct the Depositary as to the exercise of
the voting rights pertaining to the Stock represented by their respective
Depositary Shares, and (iii) a brief statement as to the manner in which such
instructions may be given. Upon the written request of a holder of this Receipt
on such record date the Depositary shall endeavor insofar as practicable to vote
or cause to be voted the Stock represented by the Depositary Shares evidenced by
this Receipt in accordance with the instructions set forth in such request.
Patterson hereby agrees to take all reasonable action that may be deemed
necessary by the Depositary in order to enable the Depositary to vote such Stock
or cause such Stock to be voted. In the absence of specific instructions from
the holder of this Receipt, the Depositary will abstain from voting to the
extent of the Stock represented by the Depositary Shares evidenced by this
Receipt.

         (16) Reports, Inspection of Transfer Books. The Depositary shall make
available for inspection by holders of Receipts at the Corporate Office, the New
York Office and at such other places as it may from time to time deem advisable
during normal business hours any reports and communications received from
Patterson that are received by the Depositary as the holder of Stock. The
Depositary shall keep books at the Corporate Office for the registration and
transfer of Receipts, which books at all reasonable times will be open for
inspection by the record holders of Receipts; provided that any such holder
requesting to exercise such right shall certify to the Depositary that such
inspection shall be for a proper purpose reasonably related to such person's
interest as an owner of Depositary Shares.

          (17) Liability of the Depositary, the Depositary's Agents, the
Registrar and Patterson. Neither the Depositary nor any Depositary's Agent nor
the Registrar nor Patterson shall incur any liability to any holder of this
Receipt, if by reason of any provision of any present or future law or
regulation thereunder of any governmental authority or, in the case of the
Depositary, the Registrar or any Depositary's Agent, by reason of any provision
present or future, of the Certificate of Incorporation or the Certificate of
Designation or, in the case of Patterson, the Depositary, the Registrar or any
Depositary's Agent, by reason of any act of God or war or other circumstances
beyond the control of the relevant party, the Depositary, any Depositary's
Agent, the Registrar or Patterson shall be prevented or forbidden from doing or
performing any act or thing that the terms of the Deposit Agreement provide
shall be done or performed; nor shall the Depositary, any Depositary's Agent,
the Registrar or Patterson incur any liability to any holder of this Receipt (i)
by reason of any nonperformance or delay, caused as aforesaid, in the
performance of any act or thing that the terms of the Deposit Agreement provide
shall or may be done or performed, or (ii) by reason of any exercise of, or
failure to exercise, any discretion provided for in the Deposit Agreement
except, in the case of the Depositary, any Depositary's Agent or the Registrar,
if such exercise or failure to exercise discretion is caused by its negligence
or bad faith.

         (18) Obligations of the Depositary, the Depositary's Agents, the
Registrar and Patterson. Patterson assumes no obligation and shall be subject to
no liability under the Deposit Agreement or this Receipt to the holder hereof or
other persons, except to perform in good faith such obligations as are
specifically set forth and undertaken by it to perform in the Deposit Agreement.
Each of the Depositary, the Depositary's Agents and the Registrar assumes no
obligation and shall be subject to no liability under the Deposit Agreement or
this Receipt to the holder hereof or other persons, except to perform such


                                      D-23
   27


obligations as are specifically set forth and undertaken by it to perform in the
Deposit Agreement without negligence or bad faith. Neither the Depositary nor
any Depositary's Agent nor the Registrar nor Patterson shall be under any
obligation to appear in, prosecute or defend any action, suit or other
proceeding with respect to Stock, Depositary Shares or Receipts or Common Stock
that in its opinion may involve it in expense or liability, unless indemnity
satisfactory to it against all expense and liability be furnished as often as
may be required. Neither the Depositary nor any Depositary's Agent nor the
Registrar nor Patterson will be liable for any action or failure to act by it in
reliance upon the advice of or information from legal counsel, accountants, any
person presenting Stock for deposit, any holder of this Receipt or any other
person believed by it in good faith to be competent to give such advice or
information.

         (19) Termination of Deposit Agreement. Whenever so directed by
Patterson, the Depositary will terminate the Deposit Agreement by mailing notice
of such termination to the record holders of all Receipts then outstanding at
least 30 days prior to the date fixed in such notice for such termination. The
Depositary may likewise terminate the Deposit Agreement if at any time 45 days
shall have expired after the Depositary shall have delivered to Patterson a
written notice of its election to resign and a successor depositary shall not
have been appointed and accepted its appointment as provided in Section 5.4 of
the Deposit Agreement. Upon the termination of the Deposit Agreement, Patterson
shall be discharged from all obligations thereunder except for its obligations
to the Depositary, any Depositary's Agent and any Registrar under Sections 5.7
and 5.8 of the Deposit Agreement. If any Receipts remain outstanding after the
date of termination of the Deposit Agreement, the Depositary thereafter shall
discontinue all functions and be discharged from all obligations as provided in
the Deposit Agreement, except as specifically provided therein.

         (20) Governing Law. The Deposit Agreement and this Receipt and all
rights thereunder and hereunder and provisions thereof and hereof shall be
governed by, and construed in accordance with, the law of the State of New York
without giving effect to principles of conflict of laws.


                                      D-24
   28


                               FORM OF ASSIGNMENT

         FOR VALUE RECEIVED, the undersigned hereby sells, assigns and transfers
unto ___________________ the within Receipt and all rights and interests
represented by the Depositary Shares evidenced thereby, and hereby irrevocably
constitutes and appoints his attorney, to transfer the same on the books of the
within-named Depositary, with full power of substitution in the premises.

Dated:

                                 Signature:
                                            -----------------------------------
                                            NOTE: The signature to this
                                            assignment must correspond with the
                                            name as written upon the face of the
                                            Receipt in every particular, without
                                            alteration or enlargement, or any
                                            change whatever.


                                      D-25