Document:

<PAGE>

                                                                    EXHIBIT 10.1

                                CONTRACT OF SALE

     THIS CONTRACT OF SALE (this "Agreement") is made and entered into as of the
20th day of December, 2001, by and between WESTPARK ACQUISITION COMPANY, INC., a
Delaware corporation ("Westpark"), and 6813 RUPPSVILLE ROAD REALTY HOLDING
COMPANY, a Delaware corporation ("Ruppsville"; together with Westpark,
collectively, "Seller") each having an address c/o J.P. Morgan Investment
Management Inc., 522 Fifth Avenue, New York, New York 10036 and KEYSTONE
OPERATING PARTNERSHIP, L.P., a Delaware limited partnership, having an address
at 200 Four Falls Corporate Center, Suite 208, West Conshohocken, Pennsylvania
19428 ("Purchaser").

                              W I T N E S S E T H:

     A. Seller shall sell to Purchaser, and Purchaser shall purchase from
Seller, at the price and upon the terms and conditions set forth in this
Agreement, (a)(1) that certain parcel of land located in Upper Macungie
Township, Pennsylvania and commonly known as Westpark Business Center, 7520,
7584, 7566, 7542, 7529 Morris Court, 7220 Schantz Road, and 7485 Industrial
Boulevard together with that certain 15.27 acre parcel of land located in Upper
Macungie Township, Pennsylvania, and more particularly described on EXHIBIT A-1
attached hereto and made a part hereof (the "Westpark Property"), and (2) that
certain parcel of land located in Upper Macungie Township, Pennsylvania and
commonly known as 6813, 6829 and 6831 Ruppsville Road and 7663 Industrial
Boulevard, and more particularly described on EXHIBIT A-2 attached hereto and
made a part hereof (the "Ruppsville Property"; together with the Westpark
Property, collectively, the "Land"), (b) the buildings, improvements, structures
and fixtures located upon the Land (collectively, the "Improvements"), (c) all
other easements and rights appurtenant to the Land, if any (collectively, the
"Appurtenant Rights"), (d) all right, title and interest of Seller in, to and
under the all leases, licenses and occupancy agreements affecting the Property
(as hereinafter defined) (the "Leases") and all service, supply and equipment
contracts and agreements related to the operation of the Property (the
"Contracts"), (e) all right, title and interest of Seller, if any, in and to the
fixtures, equipment and other personal property owned by Seller and attached or
appurtenant to the Property (collectively, the "Personal Property"), and (f) all
right, title and interest of Seller, if any, if and to the extent assignable, in
and to the name "Westpark Business Center" (the "Name"; the Land, the
Appurtenant Rights, the Improvements, the Leases, the Contracts, the Personal
Property, and the Name, collectively, the "Property").

     B. Purchaser acknowledges that the Property is being sold on an "as is"
"where is" and "with all faults" basis on the terms and conditions hereinafter
set forth.

     NOW, THEREFORE, for $10.00 in hand paid and for other good and valuable
consideration, the receipt and sufficiency of which is hereby acknowledged, and
intending to be legally bound, the parties hereto hereby agree as follows:

     1. PURCHASE AND SALE. Upon the terms and conditions hereinafter set forth,
Seller shall sell to Purchaser, and Purchaser shall purchase from Seller, the
Property.

<PAGE>

     2. PURCHASE PRICE. The purchase price (the "Purchase Price") for the
Property shall be the sum of FIFTY THREE MILLION SEVEN HUNDRED THIRTEEN THOUSAND
FIVE HUNDRED EIGHTY-THREE AND 00/100 DOLLARS ($53,713,583.00), subject to the
prorations and credits specified herein.

     3. PAYMENT OF PURCHASE PRICE. The Purchase Price, as adjusted by the
prorations and credits specified herein, shall be paid by Purchaser on the date
hereof, by a bank wire transfer of immediately available federal funds to an
account or accounts designated in writing by Seller.

     4. CONDITIONS PRECEDENT. The obligation of Purchaser to purchase, and
Seller to sell, the Property, as contemplated by this Agreement, is subject to
satisfaction of each of the following conditions precedent (any of which may be
waived in writing by the party in whose favor such condition exists) on or
before the applicable date specified for satisfaction of the applicable
condition. If any of such conditions are not satisfied (or waived) pursuant to
the terms of this Agreement, then this Agreement shall, upon written notice from
the terminating party to the other party, terminate and, in connection with any
such termination made in accordance with this Section 4, Seller and Purchaser
shall be released from further obligation or liability hereunder (except for
those obligations and liabilities which, pursuant to the terms of this
Agreement, survive such termination). The completion of Closing (as hereinafter
defined) shall constitute approval by each party of all matters to which such
party has a right of approval and a waiver of all conditions precedent;
provided, the foregoing shall not waive or otherwise impair the rights of either
party which expressly survive the Closing pursuant to this Agreement.

        4.1 Title Matters.

            4.1.1 Intentionally deleted.

            4.1.2 PERMITTED EXCEPTIONS TO TITLE. The Property shall be sold and
conveyed subject to the following exceptions to title (the "Permitted
Exceptions"):

            (a) intentionally deleted;

            (b) those exceptions to title specifically set forth in the pro
forma title insurance policies attached hereto and made a part hereof as EXHIBIT
B;

            (c) all laws, ordinances, rules and regulations of the United
States, the Commonwealth of Pennsylvania, or any agency, department, commission,
bureau or instrumentality of any of the foregoing having jurisdiction over the
Property (each, a "Governmental Authority"), as the same may now exist or may be
hereafter modified, supplemented or promulgated;

            (d) all presently existing and future liens of real estate taxes or
assessments and water rates, water meter charges, water frontage charges and
sewer taxes, rents and charges, if any, provided that such items are not yet due
and payable and are apportioned as provided in this Agreement;

            (e) any other matter or thing affecting title to the Property; and

<PAGE>

            (f) all utility easements of record which do not interfere with the
present use of the Property;

            4.1.3 SURVEY. Purchaser has ordered, at its sole cost and expense,
one or more surveys of the Property prepared by one or more surveyors registered
in the Commonwealth of Pennsylvania, to be certified by each said surveyor as
having been prepared in accordance with the minimum detail requirements of the
ALTA land survey requirements (collectively, the "Survey"). Purchaser has
instructed each surveyor to cause a copy of the Survey to be delivered to Seller
and Seller's attorneys simultaneously with the delivery of same to Purchaser.

        4.2 DUE DILIGENCE REVIEWS. Except for title and survey matters (which
shall be governed by the provisions of Section 4.1 above), Purchaser shall have
until the day prior to the date hereof, TIME BEING OF THE ESSENCE (the period of
time through and including the day prior to the date hereof being herein called
the "Due Diligence Period") within which to perform and complete all of
Purchaser's due diligence examinations, reviews and inspections of all matters
pertaining to the purchase of the Property, including all leases and service
contracts, and all physical, environmental and compliance matters and conditions
respecting the Property (collectively, the "Investigations"), which
Investigations shall at all times be subject to Purchaser's compliance with the
provisions of this Section 4.2. During the Due Diligence Period, Seller shall
provide Purchaser with reasonable access to the Property upon reasonable advance
notice and shall also make available to Purchaser, at the offices of Seller
and/or the property manager of the Property, access to such leases, service
contracts, other contracts, books, records and other documentation in Seller's
possession as Purchaser shall reasonably request, all upon reasonable advance
written notice. Any entry upon the Property and all Investigations shall be made
or performed during Seller's normal business hours and at the sole risk and
expense of Purchaser, and shall not interfere with the activities on or about
the Property of Seller, its tenants and their employees and invitees. Purchaser
shall:

            (a) promptly repair any damage to the Property resulting from any
such Investigations and replace, refill and regrade any holes made in, or
excavations of, any portion of the Property used for such Investigations so that
the Property shall be in the same condition that it existed in prior to such
Investigations;

            (b) fully comply with all laws applicable to the Investigations and
all other activities undertaken in connection therewith;

            (c) permit Seller to have a representative present during all
Investigations undertaken hereunder;

            (d) take all actions and implement all protections necessary to
ensure that the Investigations and the equipment, materials, and substances
generated, used or brought onto the Property in connection with the
Investigations, pose no threat to the safety or health of persons or the
environment, and cause no damage to the Property or other property of Seller or
other persons;

<PAGE>

            (e) furnish to Seller, at no cost or expense to Seller, copies of
all surveys, soil test results, engineering, asbestos, environmental and other
studies and reports (other than internal analysis and proprietary information of
the Purchaser) relating to the Investigations which Purchaser shall obtain with
respect to the Property promptly after Purchaser's receipt of same;

            (f) maintain or cause to be maintained, at Purchaser's expense, a
policy of commercial general liability insurance, with a broad form contractual
liability endorsement and with a combined single limit of not less than
$1,000,000 per occurrence for bodily injury and property damage, automobile
liability coverage including owned and hired vehicles with a combined single
limit of $1,000,000 per occurrence for bodily injury and property damage, and an
excess umbrella liability policy for bodily injury and property damage in the
amount of $5,000,000, insuring Purchaser, Seller, J.P. Morgan Investment
Management Inc., and Morgan Guaranty Trust Company of New York, as additional
insureds, against any injuries or damages to persons or property that may result
from or are related to (i) Purchaser's and/or Purchaser's Representatives' (as
hereinafter defined) entry upon the Property, (ii) any Investigations or other
activities conducted thereon, and/or (iii) any and all other activities
undertaken by Purchaser and/or Purchaser's Representatives, all of which
insurance shall be on an "occurrence form" and otherwise in such forms and with
an insurance company acceptable to Seller, and deliver a certificate evidencing
such insurance policy to Seller prior to the first entry on the Property;

            (g) not permit the Investigations or any other activities undertaken
by Purchaser or Purchaser's Representatives to result in any liens, judgments or
other encumbrances being filed or recorded against the Property, and Purchaser
shall, at its sole cost and expense, immediately discharge of record any such
liens or encumbrances that are so filed or recorded (including, without
limitation, liens for services, labor or materials furnished); and

            (h) indemnify Seller and any agent, advisor, representative,
affiliate, employee, director, partner, member, beneficiary, investor, servant,
shareholder, trustee or other person or entity acting on Seller's behalf or
otherwise related to or affiliated with Seller (collectively, "Seller Related
Parties") and hold harmless Seller and Seller Related Parties from and against
any and all claims, demands, causes of action, losses, damages, liabilities,
costs and expenses (including, without limitation, attorneys' fees and
disbursements), suffered or incurred by Seller or any Seller Related Party and
arising out of or in connection with (i) Purchaser's and/or Purchaser's
Representatives' entry upon the Property, (ii) any Investigations or other
activities conducted thereon by Purchaser or Purchaser's Representatives, (iii)
any liens or encumbrances filed or recorded against the Property as a
consequence of the Investigations and/or (iv) any and all other activities
undertaken by Purchaser or Purchaser's Representatives with respect to the
Property. The foregoing indemnity shall not include any claims, demands, causes
of action, losses, damages, liabilities, costs or expenses (including, without
limitation, attorneys' fees and disbursements) that result solely from the mere
discovery, by Purchaser or Purchaser's Representatives, of existing conditions
on the Property during Investigations conducted pursuant to, and in accordance
with, the terms of this Agreement.

         Without limiting the foregoing, in no event shall Purchaser or
Purchaser's Representatives, without the prior written consent of Seller: (x)
make any intrusive physical

<PAGE>

testing (environmental, structural or otherwise) at the Property (such as
soil borings, water samplings or the like), and/or (y) contact any tenant of
the Property, except to pursue Tenant Estoppels Certificates (as hereinafter
defined), and to discharge Manager's (as hereinafter defined) obligations under
the Property Management Agreement (as hereinafter defined), and for confirmatory
tenant interviews; provided, however, that Purchaser shall notify Seller of
those tenants which Purchaser desires to interview, Seller or Seller's agent(s)
shall schedule such confirmatory tenant interviews, and Seller or Seller's
agent(s) shall have the right to be present at the confirmatory tenant interview
(Purchaser acknowledges that Purchaser shall have no right to directly notify
any tenant of an interview request, and that such interview requests shall be
directed to Seller, who shall, or shall direct its agent(s) to, schedule such
confirmatory tenant interviews).

        The foregoing obligations shall survive the Closing or a termination of
this Agreement.

            4.2.1 PROPERTY INFORMATION AND CONFIDENTIALITY. Seller hereby agrees
to provide to Purchaser the Information (as hereinafter defined) subject to the
following terms and conditions:

            (a) Except as expressly provided in this Agreement, neither Seller
nor any Seller Related Party makes any representation or warranty as to the
truth, accuracy or completeness of the Information, or any other studies,
documents, reports or other information provided to Purchaser hereunder and
expressly disclaims any implied representations as to any matter disclosed or
omitted.

            (b) Purchaser agrees that, prior to the consummation of the Closing,
neither Purchaser or Purchaser's Representatives shall, at any time or in any
manner, either directly or indirectly, divulge, disclose or communicate to any
person, entity or association the Information, or any other knowledge or
information acquired by Purchaser or Purchaser's Representatives from Seller,
any Seller Related Party or by Purchaser's own inspections and investigations,
other than matters that were in the public domain at the time of receipt by
Purchaser or Purchaser's Representatives. Without Seller's prior written
consent, Purchaser shall not disclose and Purchaser shall direct Purchaser's
Representatives not to disclose to any person, entity or association or any of
the terms, conditions or other facts with respect to this Agreement, including,
without limitation, the status hereof. Notwithstanding the foregoing, Purchaser
may disclose such of the Information and its other reports, studies, documents
and other matters generated by it and the terms of this Agreement (i) as
required by law or court order (provided prior written notice of such disclosure
shall be provided to Seller) and (ii) as Purchaser deems necessary or desirable
to Purchaser's Representatives in connection with Purchaser's Investigation and
the transaction contemplated hereby, and to Purchaser's mortgage lender and
counsel to such lender, provided that those to whom such Information is
disclosed are informed of the confidential nature thereof and agree(s) to keep
the same confidential in accordance with the terms and conditions hereof.

            (c) Purchaser shall indemnify and hold harmless Seller and all
Seller Related Parties from and against any and all claims, demands, causes of
action, losses, damages, liabilities, costs and expenses (including, without
limitation, attorneys' fees and disbursements)

<PAGE>

suffered or incurred by Seller or any Seller Related Party and arising out of
or in connection with a breach by Purchaser or Purchaser's Representatives
of the provisions of this Section 4.2.1.

            (d) Purchaser and Purchaser's Representatives shall use reasonable
care to maintain in good condition all of the Information furnished or made
available to Purchaser and/or Purchaser's Representatives in accordance with
this Section 4.2. In the event this Agreement is terminated, Purchaser and
Purchaser's Representatives shall promptly deliver to Seller all originals and
copies of the Information in the possession of Purchaser and Purchaser's
Representatives; provided, however, that Purchaser may retain (but shall keep
confidential) any proprietary or other internal correspondence prepared by
Purchaser in connection with the Investigations.

            (e) As used in this Agreement, the term "Information" shall mean any
of the following to the extent supplied or made available to Purchaser or
Purchaser's Representatives by Seller or Seller's agents, including, without
limitation, the Manager: (i) all information and documents in any way relating
to the Property, the operation thereof or the sale thereof, including, without
limitation, all leases and contracts furnished to, or otherwise made available
for review by, Purchaser or its directors, officers, employees, affiliates,
partners, members, brokers, agents or other representatives, including, without
limitation, attorneys, accountants, contractors, consultants, engineers and
financial advisors (collectively, "Purchaser's Representatives"), by Seller or
any Seller Related Party or their agents or representatives, including, without
limitation, their contractors, engineers, attorneys, accountants, consultants,
brokers or advisors, and (ii) all analyses, compilations, data, studies, reports
or other information or documents prepared or obtained by Purchaser or
Purchaser's Representatives containing or based on, in whole or in part, the
information or documents described in the preceding clause (i), the
Investigations, or otherwise reflecting their review or investigation of the
Property.

            (f) In addition to any other remedies available to Seller, Seller
shall have the right to seek equitable relief, including, without limitation,
injunctive relief or specific performance, against Purchaser or Purchaser's
Representatives in order to enforce the provisions of this Section 4.2.1.

            (g) The provisions of this Section 4.2.1 shall survive the Closing
or a termination of this Agreement.

        4.3 Intentionally deleted.

        4.4 CONDITIONS PRECEDENT TO OBLIGATIONS OF PURCHASER. The obligation of
Purchaser to consummate the transactions contemplated by this Agreement shall be
subject to the fulfillment on or before the Closing Date of all of the following
conditions, any or all of which may be waived by Purchaser in its sole
discretion:

            (a) performance and observance by Seller of all covenants and
agreements of this Agreement to be performed or observed by Seller prior to or
on the Closing Date.

<PAGE>

            (b) all of the representations and warranties of Seller contained in
Section 7.1.1 of this Agreement (as modified pursuant to the terms of this
Agreement) shall be true and correct in all material respects on the Closing
Date.

        4.5 CONDITIONS PRECEDENT TO OBLIGATIONS OF SELLER. The obligation of
Seller to consummate the transactions contemplated by this Agreement shall be
subject to the fulfillment on or before the Closing Date of all of the following
conditions, any or all of which may be waived by Seller in its sole discretion:

            (a) performance and observance by Purchaser of all covenants and
agreements of this Agreement to be performed or observed by Purchaser prior to
or on the Closing Date.

            (b) all of the representations and warranties of Purchaser contained
in Section 7.3 of this Agreement shall be true and correct in all material
respects on the Closing Date.

     5. CLOSING. The closing (the "Closing") of the sale and purchase
contemplated herein shall occur on the date hereof (the "Closing Date").

        5.1 SELLER DELIVERIES. At the Closing, Seller shall deliver or cause to
be delivered to Purchaser, or to Fidelity National Title Insurance Company
("Escrowee"), as the case may be, the following items executed and acknowledged
by Seller, as appropriate:

            (a) a special warranty deed (the "Deed") in the form attached hereto
and made a part hereof as EXHIBIT C.

            (b) an assignment (the "Assignment and Assumption of Leases") of all
right, title and interest of Seller under the Leases which are in effect on the
Closing Date, without recourse, representation or warranty, in the form attached
hereto and made a part hereof as EXHIBIT D, which shall include Purchaser's
assumption of Seller's obligations under the Leases accruing from and after the
Closing Date.

            (c) a bill of sale (the "Bill of Sale") in the form attached hereto
and made a part hereof as EXHIBIT E.

            (d) a certification of non-foreign status in the form attached
hereto and made a part hereof as EXHIBIT F.

            (e) an assignment (the "Assignment and Assumption of Contracts") of
all right, title and interest of Seller under the Contracts (to the extent
assignable) which are in effect on the Closing Date and to which Seller is a
party, without recourse, representation or warranty, in the form attached hereto
and made a part hereof as EXHIBIT G, which shall include Purchaser's assumption
of Seller's obligations under the Contracts accruing from and after the Closing
Date.

<PAGE>

            (f) all existing surveys, blueprints, drawings, plans and
specifications, permits, licenses and approvals for or with respect to the
Property or any part thereof, to the extent the same are in Seller's possession.

            (g) all keys to the Improvements, to the extent the same are in
Seller's possession.

            (h) all Leases in effect on the Closing Date, to the extent the same
are in Seller's possession.

            (i) all Contracts that shall remain in effect after the Closing, to
the extent the same are in Seller's possession.

            (j) all applicable transfer tax forms, if any.

            (k) such further instruments as may be necessary to record the Deed.

            (l) notices to each of the tenants under the Leases (each, a "Tenant
Notice", and collectively, the "Tenant Notices") in the form attached hereto and
made a part hereof as EXHIBIT H, advising such tenants of the sale of the
Property to Purchaser and directing them to make all payments to Purchaser or
its designee, which Tenant Notices Purchaser shall, at Purchaser's sole cost and
expense, either mail by certified mail return receipt requested or hand-deliver
to each applicable tenant.

            (m) evidence reasonably satisfactory to Fidelity National Title
Insurance Company (the "Title Company") respecting the due organization of
Seller and the due authorization and execution by Seller of this Agreement and
the documents required to be delivered hereunder.

        5.2 PURCHASER DELIVERIES. At the Closing, Purchaser shall deliver or
cause to be delivered to Seller, or to the Escrowee, as the case may be, the
following items executed and acknowledged by Purchaser, as appropriate:

            (a) payment of the Purchase Price to be made in accordance with
Section 3 above.

            (b) the Assignment and Assumption of Leases.

            (c) the Assignment and Assumption of Contracts.

            (d) all applicable transfer tax forms, if any.

            (e) such further instruments as may be necessary to record the Deed.

            (f) the Tenant Notices.

<PAGE>

            (g) evidence reasonably satisfactory to Seller and the Title Company
respecting the due organization of Purchaser and the due authorization and
execution by Purchaser of this Agreement and the documents required to be
delivered hereunder.

        5.3 CLOSING COSTS. Seller shall pay fifty percent (50%) of all transfer
taxes, including transfer taxes of the Commonwealth of Pennsylvania and of the
County of Lehigh, payable in connection with the transaction contemplated herein
(which transfer taxes are estimated to be two percent (2%) of the Purchase
Price). Purchaser shall pay (a) fifty percent (50%) of all transfer taxes,
including transfer taxes of the Commonwealth of Pennsylvania and of the County
of Lehigh, payable in connection with the transaction contemplated herein (which
transfer taxes are estimated to be two percent (2%) of the Purchase Price), (b)
the title insurance premium for the ALTA owner's title insurance policy (the
"Owner's Policy"), (c) the cost of any title endorsements and affirmative
insurance required by Purchaser, (d) the costs of any survey (or an update
thereto), (e) all recording charges payable in connection with the recording of
the Deed, (f) all charges of Escrowee, if any, attendant to conducting the
Closing, and (g) all fees, costs or expenses in connection with Purchaser's due
diligence reviews hereunder. Any other closing costs shall be allocated in
accordance with local custom. Except as expressly provided in the indemnities
set forth in this Agreement, Seller and Purchaser shall pay their respective
legal, consulting and other professional fees and expenses incurred in
connection with this Agreement and the transaction contemplated hereby and their
respective shares of prorations as hereinafter provided. The provisions of this
Section 5.3 shall survive the Closing or a termination of this Agreement.

        5.4 Prorations.

            5.4.1 The following shall be prorated between Seller and Purchaser
as of 11:59 p.m. on the day preceding the Closing Date (on the basis of the
actual number of days elapsed over the applicable period) with the Closing Date
being a date of income and expense for Purchaser:

            (a) All real estate taxes, water charges, sewer rents, vault charges
and assessments on the Property on the basis of the fiscal year for which
assessed. In no event shall Seller be charged with or be responsible for any
increase in the taxes on the Property resulting from the sale of the Property or
from any improvements made or leases entered into on or after the Closing Date.
If any assessments on the Property are payable in installments, then the
installment for the current period shall be prorated (with Purchaser assuming
the obligation to pay any installments due after the Closing Date).
Notwithstanding anything to the contrary contained herein, taxes shall be
prorated utilizing the maximum available discount for prepayment of such taxes.

            (b) Subject to this Section 5.4.1(b), all fixed rent and regularly
scheduled items of additional rent under the Leases, and other tenant charges
if, as and when received. Seller shall deliver or provide a credit in an amount
equal to all prepaid rentals for periods after the Closing Date and all
refundable cash security deposits together with all interest thereon, if any,
payable to such tenants (to the extent the foregoing were made by tenants under
the Leases and are not applied or forfeited prior to the Closing Date) to
Purchaser on the Closing Date. Seller shall deliver to Purchaser at Closing any
security deposits which are held in the

<PAGE>

form of letters of credit. Rents which are delinquent as of the Closing Date
shall not be prorated on the Closing Date. Purchaser shall include such
delinquencies in its normal billing and shall diligently pursue the
collection thereof in good faith after the Closing Date (but Purchaser shall not
be required to litigate or declare a default in any Lease). To the extent
Purchaser receives rents on or after the Closing Date, such payments shall be
applied first toward the rents for the month in which the Closing occurs, second
to the rents for the month preceding the month in which the Closing occurs,
third to the rents that shall then be due and payable to Purchaser, and fourth
to any delinquent rents owed to Seller, with Seller's share thereof being held
by Purchaser in trust for Seller and promptly delivered to Seller by Purchaser.
Purchaser may not waive any delinquent rents nor modify a Lease so as to reduce
or otherwise affect amounts owed thereunder for any period in which Seller is
entitled to receive a share of charges or amounts without first obtaining
Seller's written consent, which consent may be given or withheld in Seller's
sole and absolute discretion. Seller hereby reserves the right to pursue any
remedy against any tenant owing delinquent rents and any other amounts to Seller
(but shall not be entitled to terminate any lease or any tenant's right to
possession), which right shall include the right to continue or commence legal
actions or proceedings against any tenant. Delivery of the Assignment and
Assumption of Leases shall not constitute a waiver by Seller of such right, and
such right shall survive the Closing. Purchaser shall reasonably cooperate with
Seller, at no cost to Purchaser, in any collection efforts hereunder (but shall
not be required to litigate or declare a default under any Lease). With respect
to delinquent rents and any other amounts or other rights of any kind respecting
tenants who are no longer tenants of the Property as of the Closing Date, Seller
shall retain all rights relating thereto.

            (c) All operating expenses.

            (d) Intentionally deleted.

            (e) Charges and payments under Contracts or permitted renewals or
replacements thereof assigned to Purchaser pursuant to the Assignment and
Assumption of Contracts.

            (f) Any prepaid items, including, without limitation, fees for
licenses which are transferred to Purchaser at the Closing and annual permit and
inspection fees.

            (g) Utilities which are not payable directly to the utility provider
by a tenant, including, without limitation, telephone, steam, electricity and
gas, on the basis of the most recently issued bills therefor, subject to
adjustment after the Closing when the next bills are available, or if current
meter readings are available, on the basis of such readings.

            (h) Deposits with telephone and other utility companies, and any
other persons or entities who supply goods or services in connection with the
Property if the same are assigned to Purchaser at the Closing, which shall be
credited in their entirety to Seller.

            (i) Personal property taxes, if any, on the basis of the fiscal year
for which assessed.

            (j) Intentionally deleted.

<PAGE>

            (k) Intentionally deleted.

            (l) Such other items as are customarily apportioned between sellers
and purchasers of real properties of a type similar to the Property and located
in the Commonwealth of Pennsylvania subject to Section 7.2.3(a) hereof.

            5.4.2

            (a) Seller shall be given a credit for any payments Seller shall
have made as of the Closing Date in respect of the expenditures described on
EXHIBIT I attached hereto and made a part hereof. Notwithstanding the foregoing,
Purchaser shall be obligated to pay any and all costs and expenses incurred
prior to, or from and after, the Closing Date, in connection with the
pre-development of Lot #6 at the Westpark Property. In addition, subject to the
provisions of this Section 5.4.2(a), Purchaser shall bear all costs and expenses
related to the transactions contemplated by that certain Lease Agreement dated
December 30, 1997 by and between Westpark, as landlord, and Behr Process
Corporation ("Behr"), as tenant (the "Behr Lease"), as amended by that certain
Amendment to Lease Agreement dated August 2, 2001 (the "Behr Amendment")
regarding the Expansion Premises (as such term is defined in the Behr Amendment)
and Behr's expansion option as set forth in the Behr Lease, including, without
limitation, (i) all outstanding construction costs and expenses incurred in
connection with the Expansion Premises (which Seller estimates to be in the
aggregate amount of $1,211,793.25) and (ii) any costs and expenses incurred in
connection with correcting outstanding HVAC issues of Behr as set forth in the
Behr Amendment.

            (b) If any of the items described in Section 5.4.1 hereof cannot be
apportioned at the Closing because of the unavailability of information as to
the amounts which are to be apportioned or otherwise, or are incorrectly
apportioned at Closing or subsequent thereto, such items shall be apportioned or
reapportioned, as the case may be, as soon as practicable after the Closing Date
or the date such error is discovered, as applicable; provided that, with the
exception of any item required to be apportioned pursuant to Section 5.4.1(a),
(b) or (g), neither party shall have the right to request apportionment or
reapportionment of any such item at any time following the one hundred eightieth
(180th) day after the Closing Date. If the Closing shall occur before a real
estate or personal property tax rate or assessment is fixed for the tax year in
which the Closing occurs, the apportionment of taxes at the Closing shall be
upon the basis of the tax rate or assessment for the preceding fiscal year
applied to the latest assessed valuation. Promptly after the new tax rate or
assessment is fixed, the apportionment of taxes or assessments shall be
recomputed and any discrepancy resulting from such recomputation and any errors
or omissions in computing apportionments at Closing shall be promptly corrected
and the proper party reimbursed, which obligations shall survive the Closing.

            5.4.3 Items to be prorated at the Closing shall include a credit to
Seller for costs and expenses incurred by Seller in connection with any new
Leases or modifications to any existing Leases entered into after the date
hereof in accordance with the terms and conditions set forth in Section 7.2.3(a)
of this Agreement.

            5.4.4 The provisions of this Section 5.4 shall survive the Closing.

<PAGE>

     6. INTENTIONALLY DELETED.

     7. REPRESENTATIONS, WARRANTIES AND COVENANTS.

        7.1 REPRESENTATIONS, WARRANTIES AND COVENANTS OF SELLER.

            7.1.1 REPRESENTATIONS AND WARRANTIES OF SELLER. Subject to the
provisions of Section 7.1.1 of this Agreement, Seller hereby represents and
warrants to Purchaser that, as of the date of this Agreement:

            (a) DUE AUTHORITY. This Agreement has been duly authorized, executed
and delivered by and is binding upon Seller. All other agreements, instruments
and documents herein provided to be executed or to be caused to be executed by
Seller are, or on the Closing Date will be, duly authorized, executed and
delivered by and are binding upon Seller. Westpark is a corporation, duly
organized and validly existing and in good standing under the laws of the State
of Delaware, and is duly authorized and qualified to do all things required of
it under this Agreement. Ruppsville is a corporation, duly organized and validly
existing and in good standing under the laws of the State of Delaware, and is
duly authorized and qualified to do all things required of it under this
Agreement.

            (b) LEASES. Seller has no knowledge of any leases, licenses or other
occupancy agreements to which Seller is a party or is bound affecting any
portion of the Property which will be in force on the Closing Date other than
the Leases. As used herein, "Leases" shall be deemed to mean, collectively, (i)
the leases currently in the possession of the Property Manager and (ii) the
leases entered into in accordance with this Agreement. Seller is the landlord or
successor landlord under the Leases. Except as may have been delivered to Seller
in writing by the Property Manager, to the best of Seller's knowledge, Seller
has not received written notice, as of the date of this Agreement, that any
Lease is not in full force and effect or asserting that Seller is in default
under any of the Leases, which default has not been cured.

            (c) LITIGATION. Except as may have been delivered to Seller in
writing by the Property Manager, to the best of Seller's knowledge, Seller has
not received written notice of any material pending or threatened litigation or
condemnation action against the Property or against Seller with respect to the
Property as of the date of this Agreement.

            (d) CONTRACTS. Seller has not entered into any service or equipment
leasing contracts relating to the Property which will be in force after the
Closing, except for the Contracts. As used in this Agreement, the "Contracts"
shall be deemed to mean, collectively, (i) the contracts currently in the
possession of the Property Manager, and (ii) contracts entered into by Seller
which Seller is permitted to enter into in accordance with this Agreement.

            (e) VIOLATIONS. Except as may have been delivered to Seller in
writing by the Property Manager, to the best of Seller's knowledge, Seller has
not received during the period of its ownership of the Property written notice
from any governmental authority that the Property is in violation of any
material law, rule, ordinance or regulation which violation remains uncured.

<PAGE>

            Notwithstanding and without limiting the foregoing, (i) if any of
the representations or warranties of Seller contained in this Agreement or in
any certificate delivered in connection herewith are materially false or
inaccurate, or Seller is in material breach or default of any of its obligations
under this Agreement, and Purchaser nonetheless closes the transactions
hereunder and purchases the Property, then Seller shall have no liability or
obligation respecting such false or inaccurate representations or warranties or
such breach or default (and any cause of action resulting therefrom shall
terminate upon the Closing) in the event that either (x) on or prior to Closing,
Purchaser shall have had knowledge of the false or inaccurate representations or
warranties or other breach or default, or (y) the accurate state of facts
pertinent to such false or inaccurate representations or warranties or other
breach or default was contained in any of the Information, and (ii) to the
extent the copies of the Leases, the Contracts or any other Information
furnished or made available to or otherwise obtained by Purchaser prior to the
execution of this Agreement contain provisions or information that are
inconsistent with the foregoing representations and warranties, such
representations and warranties shall be deemed modified to the extent necessary
to eliminate such inconsistency and to conform such representations and
warranties to such Leases and other Information.

            References to the "knowledge", "best knowledge" and/or "actual
knowledge" of Seller or words of similar import shall refer only to the current
actual (as opposed to implied or constructive) knowledge of Dianna Russo and
shall not be construed, by imputation or otherwise, to refer to the knowledge of
Seller or any parent, subsidiary or affiliate of Seller or to any other officer,
agent, manager, representative or employee of Seller or to impose upon Dianna
Russo any duty to investigate the matter to which such actual knowledge, or the
absence thereof, pertains. Notwithstanding anything to the contrary contained in
this Agreement, Dianna Russo shall have no personal liability hereunder. The
representations and warranties of Seller set forth in Section 7.1.1 shall
survive the Closing for a period of two hundred seventy (270) days, unless
litigation is, or formal adjudication proceedings are, instituted with respect
to such representation or warranty prior to two hundred seventy (270) days
following the Closing Date.

            7.1.2 GENERAL DISCLAIMER. EXCEPT AS SPECIFICALLY SET FORTH IN THIS
AGREEMENT OR IN ANY INSTRUMENT DELIVERED BY SELLER AT CLOSING, THE SALE OF THE
PROPERTY HEREUNDER IS AND WILL BE MADE ON AN "AS IS,"  "WHERE IS," AND "WITH ALL
FAULTS" BASIS, WITHOUT REPRESENTATIONS AND WARRANTIES OF ANY KIND OR NATURE,
EXPRESS, IMPLIED OR OTHERWISE, INCLUDING ANY REPRESENTATION OR WARRANTY
CONCERNING TITLE TO THE PROPERTY, THE PHYSICAL CONDITION OF THE PROPERTY
(INCLUDING THE CONDITION OF THE SOIL OR THE IMPROVEMENTS), THE ENVIRONMENTAL
CONDITION OF THE PROPERTY (INCLUDING THE PRESENCE OR ABSENCE OF HAZARDOUS
SUBSTANCES ON OR AFFECTING THE PROPERTY), THE COMPLIANCE OF THE PROPERTY WITH
APPLICABLE LAWS AND REGULATIONS (INCLUDING ZONING AND BUILDING CODES OR THE
STATUS OF DEVELOPMENT OR USE RIGHTS RESPECTING THE PROPERTY), THE FINANCIAL
CONDITION OF THE PROPERTY OR ANY OTHER REPRESENTATION OR WARRANTY RESPECTING ANY
INCOME, EXPENSES, CHARGES, LIENS OR ENCUMBRANCES, RIGHTS OR CLAIMS ON, AFFECTING
OR PERTAINING TO THE PROPERTY OR ANY PART THEREOF. PURCHASER ACKNOWLEDGES THAT,
PRIOR TO THE EXECUTION OF THIS AGREEMENT, PURCHASER HAS EXAMINED, REVIEWED AND
INSPECTED

<PAGE>

ALL MATTERS WHICH IN PURCHASER'S JUDGMENT BEAR UPON THE PROPERTY AND ITS
VALUE AND SUITABILITY FOR PURCHASER'S PURPOSES. EXCEPT AS TO MATTERS
SPECIFICALLY SET FORTH IN THIS AGREEMENT, OR IN ANY INSTRUMENT DELIVERED BY
SELLER AT CLOSING: (A) PURCHASER WILL ACQUIRE THE PROPERTY SOLELY ON THE BASIS
OF ITS OWN PHYSICAL AND FINANCIAL EXAMINATIONS, REVIEWS AND INSPECTIONS AND THE
TITLE INSURANCE PROTECTION AFFORDED BY THE OWNER'S POLICY, AND (B) WITHOUT
LIMITING THE FOREGOING, PURCHASER WAIVES ANY RIGHT IT OTHERWISE MAY HAVE AT LAW
OR IN EQUITY, INCLUDING, WITHOUT LIMITATION, THE RIGHT TO SEEK DAMAGES FROM
SELLER IN CONNECTION WITH THE ENVIRONMENTAL CONDITION OF THE PROPERTY, INCLUDING
ANY RIGHT OF CONTRIBUTION UNDER THE COMPREHENSIVE ENVIRONMENTAL RESPONSE
COMPENSATION AND LIABILITY ACT.

        7.2 INTENTIONALLY DELETED.

        7.3 REPRESENTATIONS, WARRANTIES AND COVENANTS OF PURCHASER.

            7.3.1 Purchaser hereby represents and warrants to Seller that this
Agreement has been duly authorized, executed and delivered by and is binding
upon Purchaser, and that all other and all agreements, instruments and documents
herein provided to be executed or caused to be executed by Purchaser are, or on
the Closing Date will be, duly authorized, executed and delivered by and are
binding upon Purchaser. Purchaser is a limited partnership, duly organized and
validly existing and in good standing under the laws of the State of Delaware
and is duly authorized and qualified to do all things required of it under this
Agreement.

            7.3.2 Purchaser acknowledges that Purchaser's affiliate, Keystone
Realty Services, Inc. ("Manager") acts as the property manager of the Property
on behalf of Seller pursuant to that certain Property Management Agreement dated
as of February 1, 1994, as amended, between Seller and Manager. Purchaser
represents and warrants that, to Purchaser's best knowledge, Manager has
provided to Purchaser and Purchaser is in possession of all of the leases of all
of the current tenants occupying the Property (as set forth on EXHIBIT M
attached hereto) and all of the service contracts for all the service providers
at the Property (as set forth on EXHIBIT N attached hereto).

            7.3.3 The representations and warranties of Purchaser set forth in
this Section 7.3 shall survive the Closing.

     8. RELEASE.

        8.1 INTENTIONALLY DELETED.

        8.2 RELEASE. EXCEPT FOR MATTERS SET FORTH IN THIS AGREEMENT THAT
SPECIFICALLY SURVIVE THE CLOSING OF THIS AGREEMENT, OR IN ANY INSTRUMENT
DELIVERED BY SELLER AT CLOSING THAT SPECIFICALLY SURVIVE CLOSING, EFFECTIVE AS
OF THE CLOSING, PURCHASER SHALL BE DEEMED TO HAVE RELEASED SELLER AND ALL SELLER
RELATED PARTIES FROM ALL CLAIMS WHICH PURCHASER OR ANY AGENT,

<PAGE>

REPRESENTATIVE, AFFILIATE, EMPLOYEE, DIRECTOR, OFFICER, PARTNER, MEMBER,
SERVANT, SHAREHOLDER OR OTHER PERSON OR ENTITY ACTING ON PURCHASER'S
BEHALF OR OTHERWISE RELATED TO OR AFFILIATED WITH PURCHASER (EACH, A "PURCHASER
RELATED PARTY") HAS OR MAY HAVE ARISING FROM OR RELATED TO ANY MATTER OR THING
RELATED TO OR IN CONNECTION WITH THE PROPERTY INCLUDING THE DOCUMENTS AND
INFORMATION REFERRED TO HEREIN, THE LEASES AND THE TENANTS THEREUNDER, ANY
CONSTRUCTION DEFECTS, ERRORS OR OMISSIONS IN THE DESIGN OR CONSTRUCTION OF ALL
OR ANY PORTION OF THE PROPERTY AND ANY ENVIRONMENTAL CONDITIONS, AND PURCHASER
SHALL NOT LOOK TO SELLER OR ANY SELLER RELATED PARTIES IN CONNECTION WITH THE
FOREGOING FOR ANY REDRESS OR RELIEF. THIS RELEASE SHALL BE GIVEN FULL FORCE AND
EFFECT ACCORDING TO EACH OF ITS EXPRESSED TERMS AND PROVISIONS, INCLUDING THOSE
RELATING TO UNKNOWN AND UNSUSPECTED CLAIMS, DAMAGES AND CAUSES OF ACTION.

     9. REMEDIES FOR DEFAULT.

        9.1 SELLER DEFAULTS. IF THE TRANSACTION HEREIN PROVIDED SHALL NOT BE
CLOSED BY REASON OF SELLER'S DEFAULT UNDER THIS AGREEMENT, THEN PURCHASER SHALL
HAVE, AS ITS EXCLUSIVE REMEDIES THE RIGHT TO EITHER (A) TERMINATE THIS AGREEMENT
(IN WHICH EVENT NEITHER PARTY HERETO SHALL HAVE ANY FURTHER OBLIGATION OR
LIABILITY TO THE OTHER EXCEPT WITH RESPECT TO THOSE PROVISIONS OF THIS AGREEMENT
WHICH EXPRESSLY SURVIVE THE CLOSING OR A TERMINATION OF THIS AGREEMENT),
PURCHASER HEREBY WAIVING ANY RIGHT OR CLAIM TO DAMAGES FOR SELLER'S BREACH, OR
(B) PROVIDED THE PURCHASE PRICE HAS BEEN DEPOSITED WITH ESCROWEE ON OR BEFORE
THE SCHEDULED CLOSING DATE, SPECIFICALLY ENFORCE THIS AGREEMENT (BUT NO OTHER
ACTION, FOR DAMAGES OR OTHERWISE, SHALL BE PERMITTED); PROVIDED THAT ANY ACTION
BY PURCHASER FOR SPECIFIC PERFORMANCE MUST BE FILED, IF AT ALL, WITHIN THIRTY
(30) DAYS OF THE DATE CLOSING WAS SCHEDULED TO OCCUR, AND THE FAILURE TO FILE
WITHIN SUCH PERIOD SHALL CONSTITUTE A WAIVER BY PURCHASER OF SUCH RIGHT AND
REMEDY. IF PURCHASER SHALL NOT HAVE FILED AN ACTION FOR SPECIFIC PERFORMANCE
WITHIN THE AFOREMENTIONED TIME PERIOD OR SO NOTIFIED SELLER OF ITS ELECTION TO
TERMINATE THIS AGREEMENT, PURCHASER'S SOLE REMEDY SHALL BE TO TERMINATE THIS
AGREEMENT IN ACCORDANCE WITH CLAUSE (A) ABOVE.

        9.2 PURCHASER DEFAULTS. NOTWITHSTANDING ANYTHING TO THE CONTRARY SET
FORTH IN SECTION 9.1, IN THE EVENT THE TRANSACTION CONTEMPLATED BY THIS
AGREEMENT SHALL NOT CLOSE ON ACCOUNT OF PURCHASER'S DEFAULT, THEN THIS AGREEMENT
SHALL TERMINATE, SUBJECT TO THE PROVISIONS OF THIS AGREEMENT THAT EXPRESSLY
SURVIVE THE CLOSING OR A TERMINATION OF THIS AGREEMENT; PROVIDED, HOWEVER,
NOTHING IN THIS AGREEMENT SHALL BE CONSTRUED TO LIMIT SELLER'S

<PAGE>

RIGHTS OR DAMAGES UNDER ANY INDEMNITIES GIVEN BY PURCHASER TO SELLER UNDER
THIS AGREEMENT. IN CONNECTION WITH THE FOREGOING, THE PARTIES RECOGNIZE
THAT SELLER WILL INCUR EXPENSE IN CONNECTION WITH THE TRANSACTION CONTEMPLATED
BY THIS AGREEMENT AND THAT THE PROPERTY WILL BE REMOVED FROM THE MARKET;
FURTHER, THAT IT IS EXTREMELY DIFFICULT AND IMPRACTICABLE TO ASCERTAIN THE
EXTENT OF DETRIMENT TO SELLER CAUSED BY THE BREACH BY PURCHASER UNDER THIS
AGREEMENT AND THE FAILURE OF THE CONSUMMATION OF THE TRANSACTION CONTEMPLATED BY
THIS AGREEMENT OR THE AMOUNT OF COMPENSATION SELLER SHOULD RECEIVE AS A RESULT
OF PURCHASER'S BREACH OR DEFAULT.

    10. INTENTIONALLY DELETED.

    11. MISCELLANEOUS.

        11.1 BROKERS. Seller represents and warrants to Purchaser, and Purchaser
represents and warrants to Seller, that no broker or finder has been engaged by
it, respectively, in connection with the sale contemplated under this Agreement.
In the event of a claim for broker's or finder's fee or commissions in
connection with the sale contemplated by this Agreement, then Seller shall
indemnify, defend and hold harmless Purchaser from the same if it shall be based
upon any statement or agreement alleged to have been made by Seller, and
Purchaser shall indemnify, defend and hold harmless Seller from the same if it
shall be based upon any statement or agreement alleged to have been made by
Purchaser. The indemnification obligations under this Section 11.1 shall survive
the Closing or a termination of this Agreement.

        11.2 LIMITATION OF LIABILITY.

            11.2.1 Notwithstanding anything to the contrary contained in this
Agreement or any documents executed in connection herewith, if the Closing of
the transaction contemplated hereunder shall have occurred, the aggregate
liability of Seller arising pursuant to or in connection with the
representations, warranties, indemnifications, covenants or other obligations
(whether express or implied) of Seller under this Agreement (or any document or
certificate executed or delivered in connection herewith) shall not exceed ONE
MILLION TWO HUNDRED FIFTY THOUSAND DOLLARS ($1,250,000) (the "Liability
Amount"), provided, however, that such limitation on liability shall not apply
to the obligations of Seller under Sections 5.4, 11.1 and 11.19.

            11.2.2 No shareholder or agent of Seller, nor any Seller Related
Parties, shall have any personal liability, directly or indirectly, under or in
connection with this Agreement or any agreement made or entered into under or
pursuant to the provisions of this Agreement, or any amendment or amendments to
any of the foregoing made at any time or times, heretofore or hereafter, and
Purchaser and its successors and assigns and, without limitation, all other
persons and entities, shall look solely to Seller's assets for the payment of
any claim or for any performance, and Purchaser, on behalf of itself and its
successors and assigns, hereby waives any and all such personal liability,
provided, however, subject to the terms of Section 11.2.1, the foregoing shall
not limit Purchaser's recourse to distributions of the

<PAGE>

proceeds of the sale of the Property paid by Seller to any shareholder of
Seller where Seller is unable to pay sums owed to Purchaser.

            11.2.3 The provisions of this Section 11.2 shall survive the Closing
or a termination of this Agreement.

        11.3 EXHIBITS; ENTIRE AGREEMENT; MODIFICATION. All exhibits attached
and referred to in this Agreement are hereby incorporated herein as if fully set
forth in (and shall be deemed to be a part of) this Agreement. This Agreement
contains the entire agreement between the parties respecting the matters herein
set forth and supersedes any and all prior agreements between the parties hereto
respecting such matters. This Agreement may not be modified or amended except by
written agreement signed by both parties.

        11.4 TIME OF THE ESSENCE. Time is of the essence with respect to each
and every provision of this Agreement. Whenever any action must be taken
(including the giving of notice or the delivery of documents) under this
Agreement during a certain period of time (or by a particular date) that ends
(or occurs) on a non-Business Day, then such period (or date) shall be extended
until the next succeeding Business Day. As used herein, the term "Business Day"
shall be deemed to mean any day, other than a Saturday or Sunday, on which
commercial banks in the State of New York or in the Commonwealth of Pennsylvania
are not required or authorized to be closed for business.

        11.5 INTERPRETATION. Section headings shall not be used in construing
this Agreement. Each party acknowledges that such party and its counsel, after
negotiation and consultation, have reviewed and revised this Agreement. As such,
the terms of this Agreement shall be fairly construed and the usual rule of
construction, to wit, that ambiguities in this Agreement should be resolved
against the drafting party, shall not be employed in the interpretation of this
Agreement or any amendments, modifications or exhibits hereto or thereto.
Whenever the words "including", "include" or "includes" are used in this
Agreement, they shall be interpreted in a non-exclusive manner. Except as
otherwise indicated, all Exhibit and Section references in this Agreement shall
be deemed to refer to the Exhibits and Sections in this Agreement.

        11.6 GOVERNING LAW. This Agreement shall be construed and enforced in
accordance with the laws of the Commonwealth of Pennsylvania.

        11.7 SUCCESSORS AND ASSIGNS. Purchaser may not assign or transfer its
rights or obligations under this Agreement without the prior written consent of
the Seller, which consent may be given or withheld in the sole and absolute
discretion of Seller; provided that, in the event of such an assignment or
transfer, the transferee shall assume in writing all of the transferor's
obligations hereunder (but Purchaser or any subsequent transferor shall not be
released from obligations hereunder). Notwithstanding and without limiting the
foregoing, no consent given by Seller to any transfer or assignment of
Purchaser's rights or obligations hereunder shall be deemed to constitute a
consent to any other transfer or assignment of Purchaser's rights or obligations
hereunder and no transfer or assignment in violation of the provisions hereof
shall be valid or enforceable. Subject to the foregoing, this Agreement and the
terms and provisions hereof shall inure to the benefit of and be binding upon
the successors and assigns of the parties.

<PAGE>

Notwithstanding the foregoing, Purchaser shall have the right, without
Seller's prior written consent but with prior written notice to Seller, to
assign its rights and obligations under this Agreement to one or more assignees
(not to exceed five assignees) which are wholly owned (directly or indirectly)
by Purchaser and/or Keystone Property Trust ("Permitted Assignee"), provided
that, in the event of such an assignment or transfer, the Permitted Assignee
shall assume in writing (pursuant to an assignment and assumption agreement in
form and content satisfactory to Seller in the exercise of Seller's reasonable
judgment) all of the transferor's obligations hereunder, (but Purchaser or any
subsequent transferor shall not be released from obligations hereunder). At
Purchaser's election, separate Deeds for portions of the Property designated by
Purchaser shall be delivered to Purchaser and/or its permitted assigns, provided
that Purchaser shall pay any additional costs and expenses (including, without
limitation, reasonable legal fees and expenses), if any, reasonably incurred by
Seller in connection with the preparation of such separate Deeds and/or any
related conveyance documents.

        11.8 NOTICES. All notices, requests or other communications which may be
or are required to be given, served or sent by either party hereto to the other
shall be deemed to have been properly given, if in writing and shall be deemed
received (a) upon delivery, if delivered in person or by facsimile transmission,
with receipt thereof confirmed by printed facsimile acknowledgment (with a
confirmation copy delivered in person or by overnight delivery), (b) one (1)
Business Day after having been deposited for next day overnight delivery with
any reputable overnight courier service, or (c) three (3) Business Days after
having been deposited in any post office or mail depository regularly maintained
by the United States Postal Office and sent by registered or certified mail,
postage paid, return receipt requested, and in each case, addressed as follows:

             To Seller:

             Westpark Acquisition Company, Inc.
             c/o J.P. Morgan Investment Management Inc.
             522 Fifth Avenue
             New York, New York  10036
             Attention: Dianna A. Russo
             Facsimile: (212) 837-1774
             Telephone: (212) 837-2899

             With a Copy To:

             Stroock & Stroock & Lavan LLP
             180 Maiden Lane
             New York, New York  10038-4982
             Attention: Brian Diamond, Esq.
             Facsimile: (212) 806-6006
             Telephone: (212) 806-5569

             To Purchaser:

<PAGE>

             Keystone Operating Partnership, L.P.
             200 Four Falls Corporate Center - Suite 208
             West Conshohocken, Pennsylvania 19428
             Attention: Saul A. Behar, Esq.
             Facsimile: (484) 530-0131
             Telephone: (484) 530-1825

             With a Copy To:

             Wolf, Block, Schorr & Solis-Cohen LLP
             1650 Arch Street, 22nd Floor
             Philadelphia, PA 19103
             Attention: James R. Williams, Esq.
             Facsimile: (215) 405-3732
             Telephone: (215) 977-2132

        11.9 THIRD PARTIES. Nothing in this Agreement, whether expressed or
implied, is intended to confer any rights or remedies under or by reason of this
Agreement upon any other person other than the parties hereto and their
respective permitted successors and assigns, nor is anything in this Agreement
intended to relieve or discharge the obligation or liability of any third
persons to any party to this Agreement, nor shall any provision give any third
parties any right of subrogation or action over or against any party to this
Agreement. This Agreement is not intended to and does not create any third party
beneficiary rights whatsoever.

        11.10 LEGAL COSTS. The parties hereto agree that they shall pay directly
any and all legal costs which they have incurred on their own behalf in the
preparation of this Agreement, all deeds and other agreements pertaining to this
transaction, and that such legal costs shall not be part of the closing costs.

        11.11 COUNTERPARTS. This Agreement may be executed in one or more
counterparts, each of which shall be deemed an original, but all of which shall
constitute one and the same document.

        11.12 EFFECTIVENESS. In no event shall any draft of this Agreement
create any obligation or liability, it being understood that this Agreement
shall be effective and binding only when a counterpart hereof has been executed
and delivered by each party hereto.

        11.13 NO IMPLIED WAIVERS. No failure or delay of either party in the
exercise of any right or remedy given to such party hereunder or the waiver by
any party of any condition hereunder for its benefit (unless the time specified
in this Agreement for exercise of such right or remedy has expired) shall
constitute a waiver of any other or further right or remedy nor shall any single
or partial exercise of any right or remedy preclude other or further exercise
thereof or any other right or remedy. No waiver by either party of any breach
hereunder or failure or refusal by the other party to comply with its
obligations shall be deemed a waiver of any other or subsequent breach, failure
or refusal to so comply.

        11.14 DISCHARGE OF SELLER'S OBLIGATIONS. Except as otherwise expressly
provided in this Agreement, Purchaser's acceptance of the Deed shall be deemed a
discharge of all of the

<PAGE>

obligations of Seller hereunder and all of Seller's representations,
warranties, covenants and agreements in this Agreement shall merge in the
documents and agreements executed at the Closing and shall not survive the
Closing, except and to the extent that, pursuant to the express provisions of
this Agreement, any of such representations, warranties, covenants or agreements
are to survive the Closing.

        11.15 NO RECORDATION. Neither this Agreement nor any memorandum thereof
shall be recorded and any attempted recordation hereof shall be void and shall
constitute a default hereunder.

        11.16 UNENFORCEABILITY. If all or any portion of any provision of this
Agreement shall be held to be invalid, illegal or unenforceable in any respect,
then such invalidity, illegality or unenforceability shall not affect any other
provision hereof, and such provision shall be limited and construed as if such
invalid, illegal or unenforceable provision or portion thereof were not
contained herein unless doing so would materially and adversely affect a party
or the benefits that such party is entitled to receive under this Agreement.

        11.17 WAIVER OF TRIAL BY JURY. SELLER AND PURCHASER HEREBY WAIVE TRIAL
BY JURY IN ANY ACTION, PROCEEDING OR COUNTERCLAIM (WHETHER ARISING IN TORT OR
CONTRACT) BROUGHT BY EITHER AGAINST THE OTHER ON ANY MATTER ARISING OUT OF OR IN
ANY WAY CONNECTED WITH THIS AGREEMENT.

        11.18 LIKE KIND EXCHANGE. Purchaser may desire to effectuate a
like-kind exchange pursuant to Section 1031 of the Internal Revenue Code of
1986, as amended (the "Code") in connection with this purchase of the Property.
Seller agrees to use reasonable efforts to accommodate Purchaser in effectuating
a like-kind exchange pursuant to Section 1031 of the Code in connection with the
sale of the Property; provided however, that (a) such exchange does not directly
or indirectly reduce the Purchase Price, (b) such exchange will not delay or
otherwise adversely affect the Closing, (c) there is no additional unreimbursed
loss, cost, damage, tax, expense or adverse consequence incurred by Seller
resulting from, or in connection with, such exchange (including, without
limitation, any adverse consequences under the Employee Retirement Income
Security Act of 1974, as amended), (d) Purchaser shall indemnify, save and hold
harmless Seller of, from and against any such loss, cost, damage, tax, expense
or adverse consequence (including attorneys' fees) in connection with such
exchange, (e) all documents to be executed by Seller in connection with such
exchange shall be subject to the approval of Seller, which approval shall not be
unreasonably withheld provided that Purchaser has otherwise fully complied with
the terms and provisions of this Section 11.18, and shall expressly state,
without qualification, that Seller (x) is acting solely as an accommodating
party to such exchange, (y) shall have no liability with respect thereto, and
(z) is making no representation or warranty that the transactions qualify as a
tax-free exchange under Section 1031 of the Code or any applicable state or
local laws, (f) in no event shall Seller be obligated to acquire any property or
otherwise be obligated to take title, or appear in the records of title, to any
property in connection with such exchange, and (g) Purchaser shall pay all of
the costs and expenses (including, without limitation, reasonable legal fees and
expenses) reasonably incurred by Seller in connection with the consideration
and/or consummation of any such exchange. Notwithstanding anything contained
herein to the contrary, Purchaser hereby indemnifies, saves

<PAGE>

and holds harmless Seller of, from and against any loss, cost, damage, tax,
expense or adverse consequence (including, without limitation, any adverse
consequences under the Employee Retirement Income Security Act of 1974, as
amended, and attorneys' fees) in effectuating any like-kind exchange pursuant to
Section 1031 of the Code in connection with the sale of the Property. The
provisions of this Section 11.18 shall survive the Closing.

        11.19 PENNSYLVANIA CORPORATE AND BULK SALES CLEARANCE CERTIFICATE(S).

            11.19.1 Seller shall indemnify, defend, and hold Purchaser harmless
from and against any and all losses, claims, damages and liabilities, including
without limitation reasonable attorneys' fees and costs of defense, which may be
incurred by Purchaser in connection with non-payment by Seller of any taxes of
Seller in connection with any required bulk sales clearance certificates
required to be filed in the Commonwealth of Pennsylvania by Seller in connection
with the transactions contemplated by this Agreement. Seller's obligations under
this Section 11.19 shall survive Closing.

<PAGE>

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

                                  SELLER:

                                  WESTPARK ACQUISITION COMPANY, INC., a
                                  Delaware corporation

                                  By: /s/ ANNE E. COLE
                                      ---------------------------------
                                  Name: Ann E. Cole
                                  Title: Vice President

                                  6813 RUPPSVILLE ROAD REALTY HOLDING
                                  COMPANY, a Delaware corporation

                                  By: /s/ ANNE E. COLE
                                      ---------------------------------
                                  Name: Ann E. Cole
                                  Title: Vice President

                                  PURCHASER:

                                  KEYSTONE OPERATING PARTNERSHIP, L.P.,
                                  a Delaware limited partnership

                                  By: KEYSTONE PROPERTY TRUST, a
                                      Maryland real estate investment trust,
                                      its general partner

                                  BY: /s/ STEPHEN J. BUTTE
                                      ---------------------------------
                                  Name: Stephen J. Butte
                                  Title: Senior Vice President<Page>

                           CHALLENGER MINERALS INC.
                      A Subsidiary of Global Marine Inc.
  [LOGO]
                      777 N. Eldridge Parkway, Suite 600
                             Houston, Texas 77079
                      713-266-9050      Fax 713-266-0557

October 30, 2001

REEF PARTNERS LLC
1901 N. Central Expressway, Suite 300
Richardson, Texas  75080

Attn:  Mr. H. Walt Dunagin
       Land Manager

Re:    CMI Joint Venture Agreement
       Offshore, U.S. Gulf of Mexico

Gentlemen:

Challenger Minerals Inc. ("CMI") and Reef Partners LLC, a Nevada Limited
Liability Company ("Reef") desire to enter into an agreement ("Agreement") to
facilitate the review of, and participation in, Opportunities in the U.S.
Gulf of Mexico located in water depths less than 450 feet.  The terms and
conditions governing this Agreement are as follows:

1.     TERM:  The term of this Agreement shall be for a period of three (3)
       years commencing January 31, 2002 ("Effective Date") and expiring
       January 30, 2005 ("Termination Date"), each of which years shall be
       deemed a "Participation Year"; PROVIDED, HOWEVER, that the
       confidentiality and non-competition provisions hereof shall survive
       termination of this Agreement for the contractual time period provided
       herein or in any applicable agreement with a third party or, if no such
       period is provided for, then for a period of one (1) year after the
       Termination Date.

2.     OPPORTUNITIES:  Reef shall have the right and option, but not the
       obligation, to acquire up to twelve and one-half percent (12.5%) of the
       interest made available to CMI in all Opportunities located in water
       depths less than 450 feet in the U.S. Gulf of Mexico ("Gulf of Mexico
       Shelf Program") in Prospects identified and initially reviewed by CMI
       during the term of this Agreement.  For purposes of this Agreement, an
       "Opportunity," sometimes herein also referred to as a "Prospect," is
       defined as a specific geographic area which is related to the same
       geologic structure and/or stratigraphic interval or other hydrocarbon
       trapping mechanism, and which can be commercially developed for
       hydrocarbons in accordance with standard oil and gas industry practices
       from an open

<Page>

REEF PARTNERS LLC
October 31, 2001

       water drilling location or platform.  All existing Prospects
       previously or currently under review by CMI and leases currently owned
       in whole or part by CMI are excluded from this Agreement.

3.     PARTICIPATION FEE:

       A.  In consideration of its rights hereunder to consider participation
           in Prospects, Reef shall pay CMI as a Participation Fee the total sum
           of $1,125,000.00 during the term of this Agreement, with the first
           annual payment in the amount of $375,000.00 due on or before
           November 1, 2001, a second annual payment in the same amount due on
           or before January 30, 2003 and a third annual payment in the same
           amount due on or before January 30, 2004; PROVIDED, that the first
           such payment shall not be due until a date ten (10) working days
           after Reef's timely acceptance of this proposal.  Other than such
           Participation Fee, there shall be no fees or burdens in favor of CMI
           as to the interest Reef may elect to acquire in any Prospect, and no
           obligation upon Reef to acquire an interest in any particular
           Prospect or in a minimum number of Prospects during the term of this
           Agreement.

       B.  During each Participation Year (commencing from the Effective Date)
           of the term of this Agreement, CMI shall present to Reef a minimum of
           fifty (50) separate Prospects, as to which a working interest is
           available for Reef's participation.  If during any such Participation
           Year the number of Prospects presented by CMI to Reef should be less
           than such minimum number of Prospects for Reef to consider for
           participation, Reef's Participation Fee provided for the above shall
           be proportionately reduced such that CMI would REFUND to Reef a
           portion of the fee in an amount based on the full annual fee amount
           times the deficiency number of Prospects divided by the 50 Prospect
           minimum, if requested by Reef in writing within thirty (30) days
           after the end of the applicable Participation Year.

4.     OPPORTUNITY EVALUATION:  Upon CMI being presented with potential
       opportunities to participate in Prospects generated by third parties
       ("Selling Parties"), CMI shall determine when or if a potential Prospect
       may be worthy of further consideration, and as to each potential
       Prospect, CMI shall immediately notify Reef, providing a brief
       description of the Prospect, to include when available, location,
       Operator, estimated leasehold and seismic costs and initial well costs,
       water depth and reserve potential (collectively, the "Initial Prospect
       Information").  Reef shall then promptly advise CMI whether Reef is
       already pursuing the Prospect; and, if such is the case, Reef shall
       advise CMI as to whether it will continue to pursue the Prospect on its
       own or jointly with CMI under either the terms of this Agreement or on
       other mutually acceptable terms.  If Reef elects to continue to pursue
       the Prospect on its own, the parties shall endeavor in good faith to
       resolve any areas of competition, if possible.  If Reef does not so
       notify CMI of its separate pursuit of any such potential Prospect(s)
       within ten (10) days after such initial notice by CMI (or such shorter
       period for Reef's decision as is required to prevent loss of
       opportunity), CMI and Reef shall jointly proceed as set forth in this
       Agreement.  WITH RESPECT TO ANY EVALUATIONS TO BE CONDUCTED BY EITHER
       PARTY HEREUNDER, EITHER INDIVIDUALLY

                                       2
<Page>

REEF PARTNERS LLC
October 31, 2001

       OR JOINTLY, INCLUDING AN INITIAL PROSPECT REVIEW OR A FURTHER REVIEW
       UNDER THIS PARAGRAPH 4, EACH PARTY HEREBY ACKNOWLEDGES THAT ANY SUCH
       REVIEW, AND THE METHODOLOGIES EMPLOYED THEREIN, ARE NECESSARILY
       SUBJECTIVE.  ACCORDINGLY, EXCEPT AS PROVIDED IN PARAGRAPH 4.B. BELOW,
       NEITHER PARTY MAKES ANY REPRESENTATION OR WARRANTY (WHETHER EXPRESS,
       IMPLIED, STATUTORY OR OTHERWISE) AS TO THE ACCURACY, COMPLETENESS OR
       SUFFICIENCY OF ANY SUCH EVALUATION, AND EACH PARTY DISCLAIMS ANY
       LIABILITY FOR ACCURACY OF ANY PROSPECT EVALUATION CONDUCTED BY THE
       OTHER PARTY DURING THE TERM OF THIS AGREEMENT.  EACH PARTY ACKNOWLEDGES
       AND WARRANTS THAT IT IS INDEPENDENTLY QUALIFIED TO MAKE A DECISION
       WHETHER TO INVEST IN ANY PARTICULAR PROSPECT REGARDLESS OF WHETHER IT
       PARTICIPATES IN OR CONDUCTS A REVIEW EVALUATION.

       A.  Once CMI determines that a Prospect merits a detailed geo-technical
           review with the Selling Party ("Initial Prospect Review"), it shall
           promptly so notify Reef and coordinate with Reef's technical
           personnel in scheduling the Initial Prospect Review as soon as
           practicable.

       B.  In conducting the Initial Prospect Review, and all subsequent
           geo-technical evaluations, CMI and Reef shall make a good faith
           effort to share data, knowledge, expertise and work product except
           as, and to the extent, restricted or prohibited by third-party
           Confidentiality Agreements ("CAs") and/or Area of Mutual Interest
           Agreements ("AMIAs"), to which both CMI and Reef are not similarly
           bound.  In such cases, Reef will be requested to sign and return
           expeditiously the CA or AMIA to CMI before prospect reports or data
           will be sent to Reef.  In the event that Reef is unable to
           participate in an Initial Prospect Review, CMI, as soon as
           practicable thereafter, shall make a good faith effort to review with
           Reef the Selling Party's data and interpretations and CMI's data and
           interpretations regarding the Prospect in question, subject to any
           restraints posed by such third party CAs and/or AMIs.

       C.  Following the Initial Prospect Review or other review, if conducted,
           and if not, as soon as practicable after Reef's receipt of the
           initial prospect summary from CMI, either CMI or Reef may propose
           pursuing participation in a Prospect by providing written notice of
           such intent to the other party.  The party receiving such written
           notification shall have no less than five (5) business days (or such
           shorter response time as required to prevent a loss of opportunity)
           within which to advise the other party as to whether it wishes to
           pursue the Prospect and if so, at what level of working interest,
           whether or not the parties have conducted an Initial Prospect Review
           or other review.  In the event that CMI and the Other Participants,
           (as defined in Paragraph 7) do not wish to pursue the Prospect, then
           Reef shall have the right to pursue the Prospect for its own account.
           Upon CMI's request, Reef shall advise CMI the status of its pursuit
           of such opportunity.  In the event that Reef decides to submit a
           formal participation offer to the Selling Party, Reef shall submit a
           copy thereof to CMI, and CMI shall have twenty-four (24) hours within
           which to elect to pursue the Prospect jointly with Reef in accordance
           with this Agreement.  If the participation opportunity originated
           through a request

                                       3
<Page>

REEF PARTNERS LLC
October 31, 2001

           by the Selling Party for a turnkey bid from CMI's affiliate company,
           Applied Drilling Technology, Inc. ("ADTI"), then CMI, subject to the
           exercise of its reasonable business judgment and the terms and
           conditions of  Reef's proposed offer, shall control the timing and
           content of offers to participate in the Prospect.

       D.  In the event that both CMI and Reef desire to pursue participation in
           a Prospect, they shall jointly develop and agree as to the terms and
           conditions of a written participation offer to the Selling Party.
           CMI shall have sole responsibility for direct negotiations with the
           Selling Party unless it requests the assistance of Reef.  Reef agrees
           not to directly contact the Selling Party regarding the Prospect
           during the negotiation process unless otherwise agreed to by CMI.
           However, CMI shall keep Reef advised of the progress of ongoing
           negotiations and shall solicit Reef's input and suggestions regarding
           counter-offers or subsequent revisions to original offers.
           Notwithstanding any provision to the contrary herein, if CMI
           determines any situation merits negotiation with a Selling Party
           sooner than the response time periods provided for herein in order
           to avoid a loss of opportunity to acquire an interest in a Prospect,
           CMI shall have the right to do so and shall advise Reef of the
           progress thereof.

       E.  Reef shall be an active participant with CMI in drafting, reviewing,
           and formalizing participation agreements, joint operating agreements,
           farmout agreements and all other contracts relating to its
           participation in Prospects under this Agreement.  In the event of
           disagreement between CMI and Reef as to contract terms and
           provisions, however, CMI will make the final decision as to what is
           ultimately included in all agreements, with each party reserving the
           right not to participate in the Prospect as outlined in Paragraph 5.
           CMI shall advise the Selling Party of Reef's involvement with CMI
           prior to the formulation of any such contracts, and Reef shall be a
           signatory party to all agreements executed between CMI and Selling
           Party.  CMI and Reef shall each be entitled to concurrently receive,
           directly from the Selling Party, an assignment of any ownership
           interest acquired in a Prospect.

       F.  In the event that a Selling Party does not wish to include Reef as a
           candidate for working interest participation, then CMI shall so
           advise Reef, giving the reasons given by the Selling Party.  If the
           concerns raised by the Selling Party cannot be amicably resolved, CMI
           shall have the right to pursue the Prospect for its own account and
           the Prospect shall not be covered by this Agreement.

       G.  Except for Reef's obligation to pay to CMI the Participation Fee as
           provided in Paragraph 3 above, and for CMI's obligation at its
           expense to furnish to Reef the Initial Prospect Information and
           other reports and data as provided in this Agreement, each party
           shall bear its own costs and expenses associated with the evaluation
           of each Prospect and any subsequent negotiation of a participation
           agreement or other agreement with a Selling Party.

                                       4
<Page>

REEF PARTNERS LLC
October 31, 2001

5.     RIGHT TO WITHDRAW:  CMI and Reef acknowledge that, at any time and for
       any reason during the process contemplated by Paragraph 4 (prior to the
       execution of a binding participation agreement with a Selling Party),
       either party may elect to discontinue the effort to participate in a
       Prospect.  In the event either CMI or Reef elects not to participate in
       a Prospect, the other party shall be free to continue to pursue the
       Prospect for its own account (subject to the similar rights of Other
       Participants), and the non-participating party shall not compete
       directly or indirectly against the other party in pursuing the Prospect
       for a period of one (1) year from the date of such election not to
       participate.

6.     PERSONNEL:  During the term of this Agreement, CMI will provide and
       maintain a technically proficient, multi-disciplined, veteran staff
       comprising geology, geophysics, reservoir engineering and land expertise
       to screen and evaluate Opportunities.

7.     OTHER PARTICIPANTS:  To facilitate the review of and participation in
       Prospects in the U.S. Gulf of Mexico, CMI has entered into similar joint
       venture agreements with other participants ("Other Participants")
       covering Prospects as provided for herein.  The joint venture agreements
       entered into by CMI with Reef and with the Other Participants shall be
       collectively referred to as the "CMI Joint Venture."  CMI and Reef agree
       that CMI reserves the right to terminate or amend its joint venture
       agreement with any of the Other Participants and to enter into new joint
       venture agreements with third parties.  The mention within this Agreement
       of Other Participants in the CMI Joint Venture is solely to provide Reef
       with notice of the existence of such Other Participants and their right
       to be allocated interests in Prospects under similar joint venture
       agreements with CMI.  The only relationship created pursuant to this
       Agreement, express or implied, is between Reef and CMI.   In no event
       shall it be construed that this Agreement has created any relationship,
       obligation or liability between Reef and any of the Other Participants.
       The joint participation of Reef and any of the Other Participants shall
       be pursuant to separate joint venture agreements, and any rights,
       liabilities or obligations relating to such Prospect participation shall
       be strictly limited to those as may be created by such separate joint
       venture agreements.  The term "Other Participants" in this Agreement
       shall also include CMI as to its own interest in the CMI Joint Venture,
       the CMI interest being defined as the percentage interest in the CMI
       Joint Venture remaining after crediting the sum of respective percentage
       interests in the CMI Joint Venture held by Reef, under this Agreement,
       and by Other Participants (for this purpose, excluding CMI), under their
       separate but similar joint venture agreements with CMI.

8.     WEEKLY SUMMARIES:  In order to provide for a smooth flow of information
       between the parties, CMI shall timely provide to Reef a weekly prospect
       summary.  Such weekly prospect summaries shall be subject to the
       confidentiality provisions of Paragraph 14 of this Agreement.  CMI may
       provide to Reef additional prospect summaries or updates, or additional
       prospect data, as it deems appropriate, subject to the same
       confidentiality provisions.

                                       5
<Page>

REEF PARTNERS LLC
October 31, 2001

9.     ELECTIONS AND CONFIDENTIAL INFORMATION:

       A.  CMI and Reef shall provide each other with copies of all elections
           made pursuant to joint operating agreements or any other agreements
           governing the drilling, development and operation of Prospects.
           CMI and Reef agree to freely share geological, geophysical,
           engineering and other technical data and information concerning the
           exploration, development and production of the Prospects except
           when prohibited by third party confidentiality agreements.  All
           such data shall be held strictly confidential by Reef and CMI, and
           both parties agree to abide by the terms and conditions of any
           confidentiality agreements with the Selling Party and other
           Prospect participants. Subject to the provisions of governing
           confidentiality and similar agreements (as described in Paragraph
           4.B. above) with Selling Party, all data and information regarding
           Prospects that are disclosed by one party to the other under this
           Agreement shall be held strictly confidential by the non-disclosing
           party; PROVIDED, HOWEVER, that this provision shall not apply to
           data and information that is (a) already in the public domain, (b)
           already in a party's possession at the time of disclosure, (c)
           developed by a party without the benefit or use of the confidential
           data, (d) disclosed by a third party who has the lawful right to
           make such disclosure, or (e) required to be disclosed in response
           to a judicial or administrative process from a court or
           governmental body with lawful authority to demand the production of
           same.  IN THE EVENT THAT A CLAIM IS ASSERTED AGAINST CMI OR REEF AS
           A RESULT OF AN ALLEGED VIOLATION OF THIS PROVISION BY THE OTHER
           PARTY, THE PARTY AGAINST WHOM VIOLATION IS ALLEGED SHALL DEFEND,
           INDEMNIFY AND HOLD HARMLESS THE OTHER PARTY FROM AND AGAINST ANY
           AND ALL CLAIMS, CAUSES OF ACTION AND JUDGMENTS ARISING THEREFROM,
           INCLUDING LEGAL FEES AND COURT COSTS.

       B.  Reef and its affiliates may, from time to time, provide CMI with
           certain confidential information regarding among other things,
           trade secrets, customer lists, client information, including names,
           addresses and financial information, securities brokerage firms and
           other financial institutions with which Reef and its affiliates
           transact business and certain other information regarding
           operations and business conducted by Reef (collectively, the "Reef
           Confidential Information").  CMI agrees that any confidential
           information provided to it by Reef and designated as "Reef
           Confidential Information" shall be held strictly confidential by
           CMI. CMI further agrees that, except for the benefit of Reef, it
           will not use the Reef Confidential Information or, for the term of
           this agreement and for a period of two (2) years thereafter,
           contact any persons, firms or entities designated in the Reef
           Confidential Information; PROVIDED, that this provision shall not
           relate to data and information that is already in CMI's possession
           at the time of disclosure, disclosed to CMI by a third party who
           has a lawful right to make such disclosure, or required to be
           disclosed in response to a judicial or administrative process from
           a court or governmental body with lawful authority to demand
           production of same; AND PROVIDED FURTHER, that nothing herein shall
           restrict in any way CMI's right to continue or to initiate a
           business relationship of any nature with any third party doing
           business with Reef, where such third party is already in a past or

                                       6
<Page>

REEF PARTNERS LLC
October 31, 2001

           present business relationship with CMI or where CMI obtains Reef's
           written permission, which permission shall not be unreasonably
           withheld, to discuss a business relationship with such third party.

10.    ADDITIONAL INTEREST:  Reef acknowledges that, as provided in Paragraph
       7 herein, the Other Participants (including CMI) in the CMI Joint Venture
       are also entitled to purchase certain interest in Prospects.  Reef
       shall have preferential right to acquire its proportionate share of
       an interest greater than its own original interest (i.e., the maximum
       Reef interest stated in Paragraph 2 above) out of the available
       interest in a Prospect, in the event CMI or any of the Other
       Participants elect to participate for a lesser interest or no
       interest at all in a Prospect.  The non-participating party's(ies')
       interest shall be available to the participating parties on a
       proportionate basis relative to each participating party's interest
       in the CMI Joint Venture.

11.    DISCLAIMER OF JOINT LIABILITY:  References herein to "partners" or to
       any "partnership," or references herein to any "joint venture," are
       solely for the convenience of the parties.  It is not the purpose or
       intention of this Agreement to create, and this Agreement shall never
       be construed as creating, a joint venture, a partnership, a mining
       partnership or any other legal relationship whereby CMI or Reef shall
       be held liable for the acts, either by commission or omission, of the
       other.  The liabilities and obligations of CMI and Reef arising
       hereunder shall be several, and not joint or collective.

12.    NOTICES:  All notices required herein to be given by one party to the
       other shall be given to the other party in writing by personal
       delivery, by U.S. Postal Service mail or by fax, or by telephone if
       written confirmation is sent in a manner provided above within
       twenty-four (24) hours. Notice shall be deemed to be effective upon
       actual receipt by the party to whom notice is directed; however, any
       fax received after 5:00 PM CST shall be deemed to be received on the
       following business day, excluding legal holidays. Each party's
       address, telephone and fax number shall remain as stated below (or as
       subsequently changed under the procedure set out in this paragraph)
       until such party shall give proper written notice to the other party
       of different contact information to be used for the purposes of this
       Agreement:

             REEF PARTNERS LLC
             1901 N. Central Expressway, Suite 300
             Richardson, TX 75080
             Attn:  Mr. H. Walt Dunagin, Land Manager
             Phone: (972) 437-6792
             Fax:  (972) 994-0369

                                       7
<Page>

REEF PARTNERS LLC
October 31, 2001

             CHALLENGER MINERALS INC.
             777 N. Eldridge Parkway, Suite 600
             Houston, TX 77079-4425
             Attn:  Mr. Ron Symecko, Exploration Manager, or
                    Mr. Jack D. Downing, V.P. - Field Development/East, or
                    Mr. Charles B. Hauf, V.P. - Field Development/West
             Telephone:  (713) 266-9050
             Fax:  (713) 266-0557

13.    TURNKEY BIDS:  Reef shall encourage drilling and completion turnkey bids
       in its dealings with Selling Parties, but it will not be obligated or
       penalized for any failure to do so.  Although Reef is free to pursue
       participation in any Prospect hereunder on any basis of participation
       other than under a turnkey contract with ADTI (or other turnkey
       affiliate of CMI), the parties acknowledge that mutual commitments
       herein contemplate ADTI's (or other CMI affiliate's) continuation in
       the business of providing turnkey drilling services in the Gulf of
       Mexico.  However, nothing herein shall imply that ADTI (or other CMI
       affiliate) must make a turnkey drilling bid for any particular well
       relating to any Prospect, or a bid therefor with any particular terms
       or conditions.

14.    CONFIDENTIALITY:

       A.  This Agreement is strictly confidential and shall not be shared
           with nor copies made available to  any third party, other than
           third party professional consultants retained by Reef in connection
           with the evaluation of the Opportunity or Prospect (the
           responsibility for each such consultant's compliance with the
           confidentiality and other provisions hereof being assumed by Reef),
           in whole or part, without the prior written consent of the other
           party.

       B.  Neither party shall release or distribute any information, data or
           photographs to the press, media or other parties without prior
           written approval of the other party.  When both parties have reviewed
           and approved release or distribution of the material under review,
           the party requesting release or distribution shall have the principal
           responsibility for issuance, but each party may thereafter release
           or distribute such approved material without restriction.

       C.  Nothing in this Agreement shall preclude either party from making
           such disclosures as may be required by any applicable law or
           governmental order, rule, regulation or ordinance.

15.    TRANSFER OF INTEREST:

       A.  This Agreement shall extend to and be binding upon and inure to the
           benefit of CMI and Reef and their respective successors, assigns and
           legal representatives.  However, it is understood by the parties
           hereto that this Agreement represents a "personal" covenant between
           them, and consequently that Reef may not assign in

                                       8
<Page>

REEF PARTNERS LLC
October 31, 2001

           whole or part its interest in this Agreement itself, or in its right
           hereunder to acquire any interest in any Prospect, without the
           advance written consent of CMI; PROVIDED, that such consent not to
           be unreasonably withheld; and PROVIDED FURTHER, that nothing
           herein shall preclude Reef from assigning any such interest
           hereunder if such transfer of interest is to any joint venture of
           which Reef or an affiliate is managing venturer, any partnership
           of which Reef or an affiliate is the managing partner, including
           but not limited to any partnership formed as the result of, or
           contemplated by, the Reef Global Energy Ventures Partnerships
           Registration Statement filed with the United States Securities and
           Exchange Commission, or to any Reef affiliate due to corporate
           merger, reorganization of consolidation (collectively, "Reef's
           Affiliates").  Notwithstanding the foregoing, Reef shall have the
           right to assign all or part of its interest in any Prospect
           acquired hereunder AFTER Reef shall have earned assignment of its
           interest in the Prospect from the Selling Party, subject to
           applicable restrictions in any agreements binding the participants
           in such Prospect.  In the event of an assignment of any interest
           in a Prospect by Reef, other than as more fully set forth above
           regarding assignment to Reef's Affiliates, Reef shall preserve the
           confidentiality of this Agreement by not disclosing to assignee
           the contents hereof in any form.  If such assignment should be to
           Reef's Affiliates, Reef may disclose to assignee the contents
           hereof, but shall condition such assignment upon (a) provision
           that assignee accepts all obligations of this Agreement, including
           but not limited to the confidentiality provisions hereof, and (b)
           provision that any further assignments shall be subject to the
           same restrictions hereunder originally applicable to an assignment
           by Reef, if such further assignment is made to assignor's
           affiliate due to corporate merger, reorganization or
           consolidation; PROVIDED, HOWEVER, that such confidentiality
           provision shall not apply to disclosure by Reef if Reef believes
           it is legally obligated to make such disclosure, based upon
           written legal advice of its attorney.

       B.  In the event that CMI should be sold by its parent company, Global
           Marine Inc., or undergo any type of corporate merger,
           reorganization or consolidation resulting in Global Marine Inc.
           owning less than majority interest in CMI, then CMI shall have the
           option to terminate this Agreement, effective not less than thirty
           (30) days after its written notice of same to Reef, in which event
           CMI shall refund to Reef a portion of Reef's Participation Fee
           representing the remaining portion (if any) of the current Joint
           Venture Participation Year as to which Reef shall have already
           paid such fee to CMI under Paragraph 3 of the Agreement, i.e., a
           refund amount representing the base annual fee times the remaining
           days of such Participation Year after the effective termination
           date divided by the total number of days in such year (using 365
           days).  CMI and Reef agree that the pending merger of Global
           Marine Inc. and Santa Fe International Corporation, if
           accomplished as proposed, would not trigger this provision.

       C.  Nothing in this Agreement shall be construed to create in either
           party any preferential right to purchase the interest of the other
           party, in whole or part, in

                                       9
<Page>

REEF PARTNERS LLC
October 31, 2001

           any Prospect, after a party has acquired the interest in question
           in the Prospect under the provisions of this Agreement.

16.    MISCELLANEOUS:

       A.  IN THE EVENT OF ANY DISPUTE BETWEEN THE PARTIES AS TO THE PROVISIONS
           OF THIS AGREEMENT, THE MATTER SHALL BE SUBMITTED TO ARBITRATION OR
           OTHER FORM OF ALTERNATIVE DISPUTE RESOLUTION METHOD IN HOUSTON,
           HARRIS COUNTY, TEXAS, AT THE INSTANCE OF EITHER PARTY, UNDER SUCH
           PROCEDURES AS THE PARTIES MAY AGREE UPON, OR, IF THEY CANNOT
           AGREE, THEN UNDER THE APPLICABLE RULES OF THE AMERICAN ARBITRATION
           ASSOCIATION.

       B.  Failure of a party to enforce any or all of the provisions of this
           Agreement shall not constitute a waiver of such provisions(s) or
           preclude subsequent enforcement thereof.

       C.  No provision of this Agreement shall be altered or deleted except by
           written agreement duly executed by both parties.

       D.  Any provision of this Agreement found to be illegal or unenforceable
           shall be deemed stricken so as not to affect the legality or
           enforceability of the remaining provisions.

17.    DUE DILIGENCE:  As sophisticated participants in the oil and gas
       business, Reef and CMI agree that each party is responsible for the
       scope and evaluation of its own independent "due diligence" efforts as
       to whether the business relationship and transactions contemplated
       hereunder are appropriate and suitable to their respective business
       plans.  Reef acknowledges that, in entering into this Agreement, it is
       not relying upon any representations by CMI other than those expressly
       set out herein, and that the results of Reef's participation in the
       Joint Venture may vary significantly from past results of CMI and/or
       its Joint Venture participants, for numerous reasons, including but
       not limited to general industry conditions such as oil and gas
       production pricing, drilling rig availability and the availability of
       quality Prospects for CMI to consider hereunder, and Reef's right
       hereunder to select specific Prospects for participation, and the
       percentage interest of its participation, based on its own independent
       judgment, with no obligation to participate in any particular Prospect
       or any minimum number of Prospects.

18.    CMI PARTNER BUYOUT:  This proposal is subject to CMI's success in its
       attempt to buy out or buy down the interest of Other Participants in
       existing Joint Ventures, on or before January 31, 2002, for
       consideration NOT LESS THAN Reef's monetary commitment hereunder, in
       order to place Reef into the Joint Venture for the 12.5% participation
       interest described above in Paragraph 2. Also, CMI reserves the right
       to place any available interest in the Joint Venture with Other
       Participants before placing any interest with Reef.  If for any reason
       CMI should not succeed in timely placing such 12.5%

                                       10
<Page>

REEF PARTNERS LLC
October 31, 2001

       interest in the Joint Venture with Reef, then the parties hereto agree
       that they would have no further obligation to each other under this
       proposal.

19.    INTRODUCTION OF REEF TO OTHER PARTICIPANTS:  Reef has previously agreed
       not to contact the Other Participants until CMI has introduced Reef to
       them as a possible participant in the  Joint Venture.  Upon execution
       of this Agreement, CMI shall promptly introduce Reef to the Other
       Participants.  Reef and CMI shall each have the option to terminate
       the Agreement during a period of ten (10) working days after CMI has
       given Reef written notice that CMI has introduced Reef to the Other
       Participants.  If either party has timely exercised such option to
       terminate the Agreement, by providing the other party with written
       notice of such election, the Agreement shall be considered null and
       void from inception, and each party shall be relieved of all
       obligations of any character hereunder, including but not limited to
       Reef's obligation to pay its Participation Fee provided for in
       Paragraph 3 above.

If the terms of this Agreement are acceptable to Reef, please confirm our
agreement by executing in the space provided below and returning to the
letterhead address one duplicate original to CMI's Business Development
Manager, Paul Nielsen, no later than November 7, 2001, otherwise this
proposal shall terminate and be null and void.

Very truly yours,
CHALLENGER MINERALS INC.

/s/ Tom Morrow
T. J. Morrow
President

ACCEPTED AND AGREED TO this 7 day of November, 2001:

REEF PARTNERS, LLC

By:  /s/ Michael J. Mauceli
     ----------------------
     Michael J. Mauceli
     Managing Member

                                       11

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00034-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00034-of-00352.parquet"}]]