AGREEMENT  OF  ASSIGNMENT  OF REAL  ESTATE SALE  AGREEMENT  (the
"Assignment  Agreement")  entered  into this 26th day of  April,  1996,  between
BRYMER, L.P., a Pennsylvania limited partnership ("Contract Vendee"),  having an
office  c/o 443  South  Gulph  Road,  King of  Prussia,  Pennsylvania  19406 and
CAL-TREE REALTY ASSOCIATES L.P. ("Assignee"), a Pennsylvania limited partnership
having an office c/o Cali Realty Corporation,  11 Commerce Drive,  Cranford, New
Jersey 07016.

                              W I T N E S S E T H:

                WHEREAS,  as of the 2nd day of February,  1996,  an Agreement of
Sale and  Purchase  was  entered  into  between  Adwin  Realty  Company  and LBA
Associates, as seller (collectively,  "Seller") and Contract Vendee covering the
purchase and sale of premises known as 1400  Providence  Road,  Media,  Delaware
County,  Pennsylvania  and more  particularly  described  in Exhibit "A" annexed
hereto  ("Premises"),  which  Agreement  of Sale and  Purchase  was amended by a
certain  Amendment to Agreement of Sale and Purchase between Seller and Contract
Vendee dated May 2, 1996 (collectively, the "Sales Agreement"); and

                WHEREAS,  Contract  Vendee is desirous of  assigning to Assignee
all of the right,  title and  interest  of  Contract  Vendee in and to the Sales
Agreement; and

                WHEREAS,  the  parties  agree  that any  capitalized  terms  not
otherwise defined herein shall have the meaning  attributed to them in the Sales
Agreement.

                NOW, THEREFORE,  in consideration of the Premises and the mutual
covenants expressed herein, the parties hereto hereby agree as follows:

                1.  ASSIGNMENT OF SALES AGREEMENT; ASSIGNMENT PRICE.

                (a)  Contract  Vendee  agrees to assign  to  Assignee  the Sales
Agreement,  which  assignment  shall be  effective as of the Closing (as defined
below), on the terms and conditions set forth below,  pursuant to the Assignment
of Sales Agreement (the "Assignment") annexed hereto as Exhibit "B".

                (b) The assignment  price payable to Contract  Vendee on account
of this  Assignment  Agreement  is of Six Million  ($6,000,000.00)  Dollars (the
"Assignment Price"), payable as follows:

                       (i)  Two  Hundred  Fifty   Thousand  and  XX/100  Dollars
($250,000.00)  (the  "Deposit")  to be paid to First  American  Title  Insurance
Company (the "Escrow  Agent") by wire transfer of  immediately  available  funds
received by Escrow  Agent on or before April 29, 1996,  which  Deposit  shall be
held in escrow in accordance with the provisions hereinafter set forth; and

                       (ii)  Five   Million  Five   Hundred   Seventy   Thousand
($5,750,000.00)  Dollars at Closing  (as  defined  below),  by wire  transfer of
immediately available funds to Contract Vendee subject to adjustment as provided
herein.

                       (iii)  At  Closing,  Assignee  shall  unconditionally  be
entitled to a credit in the amount of  $400,000.00  (the  "Credit")  against the
Assignment Price.

                (c) At and only upon the  Closing,  Assignee  shall  also pay to
Seller  the  amount  due  Seller  under the Sales  Agreement  on  account of the
Purchase  Price but not to exceed  Twenty Two  Million  Three  Hundred  Thousand
($22,300,000.00)  Dollars  and  subject to  adjustment  as provided in the Sales
Agreement,  which  Contract  Vendee  represents  and warrants to Assignee is the
Purchase Price.

                2.     INTENTIONALLY DELETED.

                3.     MATTERS TO WHICH THIS TRANSACTION IS SUBJECT

                Title to the Real Property and to the Personal Property shall be
as set forth in Section 5 of the Sales Agreement. Contract Vendee represents and
warrants  to  Assignee  that  it has  not  issued  any  notice  of  any  defect,
encumbrance or other title objection,  and covenants that (a) it shall not issue
any such notice without Assignee's prior consent, (b) will issue any such notice
which  Assignee  so  requests  and (c) will  exercise  the  options set forth in
Section 5(d) of the Sales Agreement as directed by Assignee.

                4.  REPRESENTATIONS AND WARRANTIES.

                (a)  Contract  Vendee for himself  only,  to induce  Assignee to
enter into this  Assignment  Agreement  and to complete the  Closing,  makes the
following  representations and warranties to Assignee, which representations and
warranties are true and correct as of the date of this Assignment Agreement, and
shall be true and  correct at and as of the  Closing in all  respects  as though
such representations and warranties were made both at and as of the date of this
Assignment Agreement, and at and as of the Closing:

                       (i) annexed hereto as Exhibit "C" is a true, complete and
correct  copy of the  Sales  Agreement,  which  Sales  Agreement  has  not  been
modified,  changed or amended and which Sales  Agreement  represents  the entire
agreement between Contract Vendee and Seller with respect to the Premises;

                       (ii) to the best of Contract  Vendee's actual  knowledge,
the Sales  Agreement  is in full force and effect,  is a valid  contract  and is
legally enforceable in accordance with its terms;

                       (iii)  Contract  Vendee  has,  to the best of his  actual
knowledge,   heretofore  timely  performed  and  observed  all  of  the  duties,
obligations,  terms,  covenants and conditions of the Sales Agreement on the its
part to be performed or observed thereunder;

                       (iv) all representations contained in the Sales Agreement
made by Contract Vendee,  and to the best knowledge of Contract Vendee,  made by
Seller, are and continue to be true and correct;

                       (v) neither  Seller nor  Contract  Vendee has  declared a
default under the Sales Agreement,  and to the best of Contract  Vendee's actual
knowledge, no event has occurred or failed to occur which, but for the giving of
notice or passage of time,  or both,  would  constitute a default  thereunder by
either Seller or Contract Vendee;

                       (vi)  Contract   Vendee  has  not   assigned,   conveyed,
encumbered, mortgaged, pledged or transferred all or any part of its interest in
the Sales Agreement other than a certain prior Agreement to Form Partnership, as
amended,  entered  into by Contract  Vendee and  Berwind  Property  Group,  Inc.
("BPG") relating to the Premises and the Sales  Agreement.  BPG has consented to
the execution,  delivery and performance of this Assignment Agreement by Contact
Vendee and that no further authorization from BPG is required to so perform. BPG
agrees,  represents  and  warrants,  by  its  execution  and  delivery  of  this
Assignment  Agreement  for the  limited  purpose  of  joining  in  this  and the
following  paragraph,  that it has not  entered  into  any  assignment  or other
agreement which, by its terms or in the performance thereof, would conflict with
or result in a breach of this Assignment  Agreement.  Assignee agrees that based
upon the foregoing,  it will look solely to Contract  Vendee for the performance
of Contract Vendee's obligations,  representations and warranties hereunder, and
that BPG will have no obligations or liabilities with respect  thereto.  Nothing
herein  contained  shall be deemed to modify or alter the respective  rights and
obligations of BPG and Contract Vendee under the terms of the BPG Agreement;

                       (vii) No person,  firm,  corporation  or other entity has
any right or option to  acquire  the  Premises  or any part  thereof  other than
Assignee and BPG as set forth in the preceding paragraph;

                       (viii)  Contract  Vendee has delivered to Assignee  true,
correct  and  complete  copies  any and  all  material  documents,  instruments,
agreements  and other  items in its  possession  with  respect to the  Premises,
including  without  limitation the Tenant Leases,  the Service  Agreements,  the
Recorded Agreements, the Tenant Estoppel Certificates,  any schedules, summaries
and projections of tenant improvement costs and leasing commission  obligations,
tenant  profiles and summaries and  structural,  engineering  and  environmental
assessment reports in Contract Vendee's possession with respect to the Premises;

                       (ix) Contract  Vendee has not received from Seller or any
other party any notice of any  litigation,  insurance  claim,  personal  injury,
proceeding  (zoning  or  otherwise)  or  governmental  investigation  pending or
threatened  against or relating to the Premises or the transaction  contemplated
by the Sales Agreement other than as set forth on Exhibit "D" annexed hereto; to
the extent any matter is set forth on Exhibit "D";

                       (x) To the best of Contract Vendee's knowledge,  the only
leases,  tenancies,  licenses and other  agreements for the use and occupancy of
any  portion of the  Premises  other than the  Tenant  Leases are those  leases,
tenancies,  licenses and other agreements listed on Exhibit "E" (the "Additional
Leases"),  which  Exhibit is a true,  correct and  complete  list of  Additional
Leases; the  representations and warranties of Seller with respect to the Tenant
Leases set forth in Sections 8(b) through (m) of the Sales  Agreement are hereby
deemed  repeated in their  entirety  in this  Assignment  Agreement  by Contract
Vendee with respect to the Additional  Leases and Exhibit "E", and therefore all
references in said Sections to Seller,  Tenant Leases and Exhibit "G" are hereby
deemed  references  to  Contract  Vendee,  Additional  Leases  and  Exhibit  "E"
respectively;

                       (xi)  Annexed  hereto as Exhibit "H" is a true,  complete
and  correct  schedule  of the  economic  terms of the  leases  currently  under
negotiation by Seller or Contract  Vendee with  Principal  Mutual Life Insurance
Company   ("Principal"),   Barnett   International   ("Barnett")   and  Anixeter
("Anixeter");

                       (xii) Annexed  hereto as Exhibit "F" is a true,  complete
and correct  schedule of the leasing  commission  agreements  for the Additional
Leases;

                       (xiii) To the best of Contract Vendee's knowledge,  there
has been no  material  adverse  change  in the  status  of the  Premises  or any
contracts  or  agreements   relating  thereto   (including   without  limitation
additional  leases,  renewals  or  amendments  thereto,  or  additional  service
contracts) except for Additional Leases; and

                       (xiv)  The  execution  and  delivery  of this  Assignment
Agreement and the performance by Contract  Vendee of its  obligations  hereunder
will not conflict with or result in a breach of any law, regulation or order, or
any  agreement or  instrument  to which  Contract  Vendee is a party or by which
Contract Vendee is bound; and this Assignment  Agreement and the documents to be
delivered by Contract  Vendee  pursuant to this  Assignment  Agreement will each
constitute  the  legal,  valid  and  binding  obligations  of  Contract  Vendee,
enforceable in accordance with their respective terms, covenants and conditions;
and there are no claims,  defenses  (personal  or  otherwise)  or offsets to the
validity  of or  enforceability  against  Contract  Vendee  of  this  Assignment
Agreement and the documents to be delivered pursuant hereto.

                (b)  Assignee,  to induce  Contract  Vendee  to enter  into this
Assignment Agreement and to complete the Closing, hereby represents and warrants
to Contract Vendee that the execution and delivery of this Assignment  Agreement
and the performance by Assignee of its  obligations  hereunder will not conflict
with or result in a breach of any law,  regulation or order, or any agreement or
instrument to which Assignee is a party or by which Assignee is bound;  and this
Assignment  Agreement and the documents to be delivered by Assignee  pursuant to
this  Assignment  Agreement will each  constitute  the legal,  valid and binding
obligations of Assignee,  enforceable in accordance with their respective terms,
covenants  and  conditions;  and  there are no  claims,  defenses  (personal  or
otherwise) or offsets to the validity of or  enforceability  against Assignee of
this  Assignment  Agreement and the documents to be delivered  pursuant  hereto.
This  representation  and  warranty  is true and  correct as of the date of this
Assignment Agreement,  and shall be true and correct at and as of the Closing in
all respects as though such  representation and warranty was made both at and as
of the date of this Assignment Agreement, and at and as of the Closing.

                5.  COVENANTS.

                Contract  Vendee  hereby  covenants  and agrees that between the
date hereof and the Closing,  and with respect to the Closing,  it shall perform
and observe the following with respect to the Premises and the Sales Agreement:

                       (a) Contract  Vendee shall continue to timely perform and
observe all of the duties,  obligations,  terms, covenants and conditions of the
Sales Agreement on its part to be performed or observed thereunder;

                       (b) Contract Vendee shall not modify,  terminate,  amend,
cancel, surrender or, with the exception of this Assignment Agreement,  make any
agreement affecting the Sales Agreement without first obtaining Assignee's prior
written consent, which consent shall not be unreasonably withheld or delayed;

                       (c) It shall not grant any  consents  or  approvals  with
respect to the  Premises  and shall not enter into or caused to be entered  into
any  agreements,  leases,  tenancies,  licenses or contracts with respect to the
Premises without first obtaining Assignee's prior written consent, which consent
shall not be unreasonably withheld or delayed;

                       (d) It will use its reasonable efforts to cause Seller to
operate and maintain  the  Premises in the  ordinary  course of business and use
reasonable  efforts to cause  Seller to  reasonably  preserve  for  Assignee the
relationships  of tenants,  suppliers,  managers,  employees  and others  having
on-going  relationships  with the Premises,  and use reasonable efforts to cause
Seller to not defer taking  actions or spending its funds,  or otherwise  manage
the Premises  differently,  due to the pending sale of the  Premises,  except as
specifically permitted in the Sales Agreement;

                       (e)  It  shall   forward   to   Assignee   all   notices,
communications,  demands or requests received by Contract Vendee with respect to
the Premises promptly after receipt;

                       (f) In  the  event  Seller  shall  not  consent  to  this
Assignment  Agreement  on or before the earlier of the Closing  hereunder or the
Closing Date under the Sales  Agreement,  then at Assignee's  request,  Contract
Vendee  shall  exercise  its right to extend the  Closing  Date as  provided  in
Section 4(b) of the Sales Agreement.  In connection  therewith,  Contract Vendee
represents and warrants to Assignee that the Inspection Period expired April 22,
1996 and that the Closing Date under the Sales  Agreement  is June 21, 1996.  If
Assignee shall make said request, then it shall provide Contract Vendee with the
$50,000.00  to be  deposited  by  Contract  Vendee  in  order to  exercise  such
extension,  and  Assignee  and  Contract  Vendee  shall  enter  into a  mutually
acceptable letter agreement evidencing Assignee's sole right, title and interest
in and to said  amount and that if said  amount is to be  refunded  to  Contract
Vendee in accordance with the Sales Agreement or otherwise, said amount shall be
paid directly to Assignee;

                       (g) At least ten (10) days prior to the  Closing,  advise
Seller  that  Contract  Vendee has  assigned  the Sales  Agreement  to  Assignee
effective  as of the Closing and use its best efforts to cause Seller to prepare
and execute all documents,  items and  instruments to be delivered at Closing in
the name and for the benefit of Assignee;

                       (h) Contract Vendee shall include Assignee and its agents
in all  aspects  in the  closing  of the Sales  Agreement,  including  by way of
example and not limitation, closing documents and closing adjustments,  provided
that Closing under this Assignment Agreement occurs  simultaneously with closing
under this Sales Agreement;

                       (i) Contract  Vendee shall cooperate in all respects with
Assignee in connection with the acquisition by Assignee of the Premises; and

                       (j) If, as of the  Closing  Date,  there  shall occur any
event giving rise to the making of an election  under Section 14(b) of the Sales
Agreement, then the following shall apply:

                               (i) so long as Assignee is nevertheless  prepared
to acquire the Premises if the  condition  can be satisfied by Seller,  Contract
Vendee shall not terminate its obligations  under the Sales  Agreement.  In such
event,  if Seller consents to the assignment of the Sales Agreement to Assignee,
Assignee  shall be obligated to perform its  obligations  hereunder and Assignee
shall have the sole right to make said election;  if Seller does not so consent,
the Closing hereunder shall be extended to the date Seller is obligated to close
under the Sales  Agreement and Contract  Vendee and Assignee  shall each perform
their respective obligations hereunder.  If Contract Vendee is prepared to waive
said  condition,  then  Assignee  agrees to close  hereunder or  terminate  this
Assignment Agreement on or prior to June 2, 1996; and

                               (ii) if Assignee  is not  prepared to acquire the
Premises due to such condition, then this Agreement shall terminate, the Deposit
shall be returned to Assignee, and the parties shall have no further obligations
to the other except as shall  specifically  survive such termination as provided
herein.

                6.  INTENTIONALLY DELETED.


                7.  ITEMS TO BE DELIVERED OR CAUSE TO BE DELIVERED BY
                             CONTRACT VENDEE ON THE CLOSING DATE

                On the  Closing  Date,  Contract  Vendee,  at its sole  cost and
expense, will deliver or cause to be delivered to Assignee the following:

                       (a) All of the  documents,  items and  instruments  to be
delivered by Seller under and pursuant to the Sales  Agreement,  provided,  that
Closing under this Assignment  Agreement occurs  simultaneously with the Closing
under the Sales Agreement;

                       (b) Any  documents  reasonably  required  by  Assignee or
necessary  in  order  to  effectuate  the  transactions   contemplated  by  this
Assignment   Agreement,   including  by  way  of  example  and  not  limitation,
affidavits, assurances, acknowledgements, deeds, and transfer tax returns;

                       (c) The Assignment;

                       (d) An  affidavit  on account of  Contract  Vendee in the
form of Schedule "N", FIRPTA Affidavit, to the Sales Agreement; and

                       (e) Any agreements contracts, reports, analysis, studies,
leases, licenses,  tenancies,  material, documents and items with respect to the
Premises which have not previously been delivered to Assignee.

                8.     SURVIVAL OF REPRESENTATIONS, WARRANTIES
                                 AND OBLIGATIONS

                The  representations,  warranties  and  obligations  of Contract
Vendee set forth in Sections 4(a) (i), (vi) and (vii) shall remain in effect for
a period of one (1) year  following the Closing and thereafter if Assignee shall
have given to Contract  Vendee  notice of a breach  thereof  within one (1) year
period.

                9.     OBLIGATIONS WITH RESPECT TO SALES AGREEMENT.

                Contract  Vendee and Assignee  hereby agree as to the  following
with respect to certain of the  obligations  of Contract  Vendee under the Sales
Agreement and this Assignment Agreement:

                       (a)  Assignee  shall pay an amount  which is equal to the
amount Contract Vendee is obligated to pay pursuant to Section 7(d) of the Sales
Agreement  less   $50,000.00,   and  one-half  (1/2)  of  all  realty  transfer,
recordation and documentary fees, stamps and taxes imposed on an amount equal to
the Assignment  Price less the Credit.  Contract Vendee shall pay the $50,000.00
balance of the amount it is  obligated  to pay  pursuant to Section  7(d) of the
Sales  Agreement,  and one-half (1/2) of all realty  transfer,  recordation  and
documentary  fees, stamps and taxes imposed on an amount equal to the Assignment
Price  less the  Credit,  plus  100% of all  realty  transfer,  recordation  and
documentary fees, stamps and taxes imposed on the Credit.  Contract Vendee's tax
obligation  attributable  to the  Assignment  Price  shall be held in  escrow by
Pryor,  Cashman,  Sherman & Flynn ("PCS&F") pending a final determination by the
Pennsylvania  Supreme  Court  regarding  taxes of this  type.  If it is  finally
determined  that said tax is due, then such amount shall be promptly paid to the
appropriate taxing authority;  if it is determined that no such tax is due, then
such amount shall be promptly returned to Contract Vendee;

                       (b) Any claims  arising  out of Contract  Vendee's  entry
upon the Premises shall be the responsibility of Contract Vendee, and any claims
arising out of Assignee's entry upon the Premises shall be the responsibility of
Assignee;

                       (c)  Contract  Vendee  shall  be  obligated  to make  the
payments required of it pursuant to Section 17 of the Sales Agreement; and

                       (d)  Contract  Vendee  shall  be  obligated  to make  all
payments due on account of leasing commissions and costs for tenant improvements
for the  Additional  Leases  and the New Leases (as  defined  below),  or to the
extent  applicable  as  provided  in Section 12 herein,  Alternative  Leases (as
defined below).  Assignee shall be obligated to pay leasing commissions pursuant
to the  commissions  scheduled  on Exhibit  "G" annexed  hereto for  renewals or
expansions of Tenant Leases and leasing  commissions  for renewals or expansions
pursuant to the commissions scheduled on Exhibit "F" annexed hereto with respect
to Additional  Leases and New Leases, or to the extent  applicable,  Alternative
Leases.

                10.    TITLE.

                Notwithstanding  anything to the contrary contained in the Sales
Agreement,  title to the  Premises  shall be  insured  by First  American  Title
Insurance  Company of New York or such other title company  selected by Assignee
which is licensed in the State of Pennsylvania (the "Title  Company").  Assignee
has procured a report of title from the Title Company,  and instructed the Title
Company to forward same to counsel for Contract Vendee. If title to the Premises
is not conveyed to Assignee  pursuant to the Sales Agreement and this Assignment
Agreement as a result of any act of Contract  Vendee,  Contract  Vendee shall be
responsible for all title fees,  survey expenses and search charges of the Title
Company.  In all other events,  Assignee shall be responsible  for the premiums,
costs and expenses of the Title  Company.  Contract  Vendee shall be responsible
for the costs and expenses of Certified  Abstract Co., Inc. as long as Certified
Abstract Co., Inc does not provide title hereunder.

                11.    CONDITIONS PRECEDENT TO ASSIGNEE'S OBLIGATIONS.

                The obligations of Assignee to accept the Assignment, to acquire
the Premises and to perform the other  covenants and obligations to be performed
by Assignee on the Closing shall be subject to the following  conditions (all or
any of which may be waived, in whole or in part, by Assignee):

                       (a) The  representations and warranties made by Seller in
the Sales Agreement and Contract  Vendee in this  Assignment  Agreement shall be
true and correct in all  respects  with the same force and effect as though such
representations  and warranties  had been made on and as of the Closing,  except
that for purposes of this paragraph (a), the  representations  and warranties of
Contract  Vendee shall be without  regard to any knowledge  standard of Contract
Vendee.

                       (b) Seller and Contract Vendee, respectively,  shall have
performed all covenants  and  obligations  undertaken by Seller in Section 10 of
the  Sales  Agreement  and  Contract  Vendee  in  Section  5 of this  Assignment
Agreement in all respects and complied with all conditions required by the Sales
Agreement and this  Assignment  Agreement to be performed or complied with by it
on or before the Closing.

                       (c) The  satisfaction by Seller of its obligations as set
forth in Section  14(a) of the Sales  Agreement  shall be subject to  Assignee's
approval.

                       (d) The Title  Company is prepared to issue to Assignee a
Title  Policy  meeting  the  requirements  set  forth in  Section 5 of the Sales
Agreement subject only to the payment of the premium therefore by Assignee.

                       (e) Seller and Contract Vendee, respectively,  shall have
delivered to Assignee all of the documents enumerated in Section 15 of the Sales
Agreement and Section 7 of this Assignment Agreement.

                12.    NEW LEASE OBLIGATIONS.

                Contract  Vendee is currently  negotiating  leases with Barnett,
Anixeter  and  Principal  for vacant  space at the  Premises.  As a condition to
Closing hereunder, Contract Vendee hereby agrees as follows:

                       (a)  (i)  A  portion  of  the  Assignment  Price  in  the
aggregate  amount of 110% of the  tenant  improvement  allowances  (the  "Tenant
Improvement  Fund")  granted  under the New Leases set forth on Exhibit "I" (the
"New Leases"), 100% of the brokerage commissions relating to the New Leases (the
"Brokerage  Fund") set forth on  Exhibit  "I" and 100% of a full  year's  annual
fixed  rent  under each New Lease set forth on  Exhibit  "I" (the  "Annual  Rent
Fund") be  remitted  directly  to PCS&F and held by PCS&F who shall act  jointly
with Adelman  Lavine Gold and Levin as escrow agent  pursuant to the terms of an
escrow agreement (the "Escrow  Agreement") to be agreed upon between the parties
hereto and  reflecting  the  provisions  of this  Section  12.  Interest on said
account,  and on  account of the escrow  for  transfer  taxes,  shall be paid to
Contract Vendee.

                          (ii) Upon the full  execution and delivery of each New
Lease by Contract  Vendee,  PCS&F shall  disburse the escrowed funds as follows:
(x)  for  tenant  improvement  costs,  on a  progress  basis  out of the  Tenant
Improvement  Fund  pursuant to  invoices  submitted  by the  general  contractor
provided (i) the work is performed in accordance  with the applicable New Lease,
(ii) lien waivers are  delivered  by the  appropriate  subcontractors  and (iii)
Contract Vendee  delivers a certificate  prior to each  disbursement  warranting
that the balance of the Tenant  Improvement  Fund  allocable  to said New Lease,
after such payment, will be sufficient to complete the tenant improvements under
such New Lease; (y) for brokerage  commissions,  the amount then due pursuant to
the applicable  brokerage  agreements  against invoices submitted by the brokers
thereunder,  and (z) to Contract  Vendee,  an amount  equal to 80% of the Annual
Rent Fund  related to such New  Lease,  unless  (i) such New Lease  permits  the
tenant to terminate the lease as a result of Landlord's  failure to complete the
tenant  improvements  by a date  certain or (ii) such New Lease is executed  and
delivered  less than  thirty (30) days prior to the rent  commencement  date set
forth in Exhibit  "H", in which event the total Annual Rent Fund shall remain in
escrow until the balance  thereof is otherwise to be released to Contract Vendee
as provided in (iii) below.  Notwithstanding  anything to the contrary contained
in this subsection 12(a)(ii),  if the New Lease(s) are executed and delivered to
Assignee but Contract Vendee or its affiliate, acting as general contractor, has
failed to commence or  diligently  continue  working on the tenant  improvements
under  such New  Lease,  Assignee  shall  have the right to  perform  the tenant
improvement work required under the New Lease and utilize the Tenant Improvement
Fund for such purpose.

                          (iii)  If  the  tenant  under  a New  Lease  fails  to
commence  paying  rent by the  date  set  forth on  Exhibit  "H" as a result  of
Contract Vendee failing to complete timely the tenant improvements, Assignee may
draw down and retain on a monthly  basis the balance of the Annual Rent Fund, to
pay monthly rent until such time as tenant's  obligations to pay rent commences.
Thereafter,  the  balance  of the  allocable  Annual  Rent Fund shall be paid to
Contract Vendee. If the tenant under a New Lease is obligated to commence paying
rent by said date,  the balance of the allocable  Annual Rent Fund shall be paid
to Contract Vendee.

                          (iv) Assignee  hereby  consents to Contract  Vendee or
its affiliated construction entity performing the tenant improvements on account
of the New Leases.  If Contract  Vendee or its  affiliated  construction  entity
shall not perform said work,  then  Assignee  shall have the right to select the
contractor therefor.

                          (v)  Contract  Vendee  shall  have the right to submit
requisitions  every  fourteen  (14) days,  and PCS&F shall  expedite  payment on
account of said requisition by wire transfer to Contract Vendee as expeditiously
as possible.

                       (b) In the event  that one or more of the New  Leases are
not executed and delivered to Assignee at Closing, then in substitution thereof,
Contract Vendee shall have the nonexclusive right to pursue an alternative lease
(an  "Alternative  Lease")  for each New Lease not so  executed  and  delivered.
Provided the following conditions are met:

                          (i) the economic term of the  Alternative  Lease shall
be equal to or more  favorable  than  those  set  forth in  Exhibit  "H" for the
corresponding space,  including,  at Contract Vendee's election,  the payment to
Assignee of the monies held in the Annual Rent Fund;

                          (ii) the  creditworthiness  of the  tenant  under  the
Alternative  Lease shall be equal to or more  favorable  than the average of the
creditworthiness of the balance of the tenants at the Premises;

                          (iii) the Alternative Lease is on a form, and contains
terms and conditions,  reasonably acceptable to Assignee and Contract Vendee and
shall be comparable to the leases in the marketplace for such tenants;

                          (iv) the tenant under the Alternative  Lease is a bona
fide third party and has executed the Alternative Lease; and

                          (v)  Assignee  has not entered  into leases for any of
such space,

then the terms and  conditions  set forth in  Section  12(a)  applicable  to New
Leases shall apply to the Alternative Lease(s).  In addition,  Contract Vendee's
obligations  with respect to such Alternative  Lease shall be deemed  satisfied,
whether or not Assignee shall enter into said Alternative Lease.

                       (c) In the event that one or more of the New Lease(s) are
not  delivered  at Closing  and  Assignee  secures  alternative  tenants for the
unleased space,  Assignee may use the Tenant  Improvement Fund and the Brokerage
Fund for their  intended  purposes  but on account of the leases so  procured by
Assignee, and shall be entitled to monthly payments, commencing on the dates set
forth in Exhibit "H", from the Annual Rent Fund in the monthly amounts set forth
on Exhibit "I" until the  tenant(s)  so procured  by  Assignee  commence  rental
payments on a regular basis.  On such date, any amounts  remaining in escrow for
said space shall be released to Contract Vendee. Assignee agrees not to exercise
the rights in this  paragraph (c) for a period of four (4) months  following the
Closing hereunder.

                13.  CLOSING.

                The closing under this Assignment  Agreement shall take place on
or about May 2, 1996 (the "Closing"),  at the time and location specified in the
Sales Agreement,  unless extended in accordance with this Assignment  Agreement.
This  transaction  shall be  consummated  simultaneously  with  the  transaction
covered by the Sales Agreement. The Premises shall be conveyed directly from the
Seller to  Assignee  at the  Closing so as to vest title to the  Premises in the
Assignee pursuant to the terms of the Sales Agreement.

                14. BROKER

                Contract Vendee and Assignee  represent that they have not dealt
with any brokers, co- brokers,  consultants,  finders or salesmen except Jackson
Cross Co. (the "Broker") in connection with this Assignment Agreement, and agree
to indemnify,  defend and hold each other  harmless from and against any and all
loss, cost, damage, liability or expense,  including reasonable attorneys' fees,
which they may  sustain,  incur or be exposed to by reason of any claim for fees
or  commissions  by any party acting by,  through or under the  indemnitor.  The
commission  payable to Broker shall be paid by Contract Vendee.  This Section 14
shall survive the Closing or earlier termination of this Assignment Agreement.

                15.  REMEDIES.

                       (a)  In  the  event  Assignee  fails  to  perform  on the
Closing,  Assignee's sole liability and Contract Vendee's sole recourse shall be
limited to the amount of the Deposit.  Contract  Vendee agrees that retention of
the Deposit  constitutes fixed and liquidated  damages resulting from Assignee's
default, and Contract Vendee waives any other claim, at law or in equity, either
against  Assignee  or  against  any  person,  known  or  unknown,  disclosed  or
undisclosed.

                       (b)  (i) If,  after  complying  with  the  terms  of this
Assignment  Agreement,  Contract Vendee shall be unable to perform in accordance
with the terms of this  Assignment  Agreement,  Contract Vendee shall direct the
Escrow  Agent to refund to  Assignee  the  Deposit,  whereupon  this  Assignment
Agreement shall be deemed  cancelled and the parties hereto shall be released of
all obligations and liabilities  under this Assignment  Agreement,  except those
that are expressly  stated to survive the  cancellation  or  termination of this
Assignment Agreement.

                          (ii) In the event of any default on the part of Seller
or Contract Vendee,  or Seller's or Contract Vendee's failure to comply with any
representation,  warranty  or  agreement  in  the  Sales  Agreement  or  herein,
respectively,  which  Contract  Vendee has  failed to cure  within ten (10) days
after receipt of written notice from Assignee of such default, Assignee shall be
entitled to (a)  terminate  this  Assignment  Agreement  upon notice to Contract
Vendee, in which event the Deposit shall be returned by Escrow Agent to Assignee
and neither  party shall  thereafter  have any  further  obligations  under this
Assignment Agreement,  (b) commence an action against Seller, Contract Vendee or
both seeking specific  performance of Seller's and Contract Vendee's obligations
under the Sales Agreement and this Assignment Agreement,  respectively or (c) in
the event of a willful  default by Seller  under the Sales  Agreement,  Contract
Vendee under the Assignment Agreement,  or both, Assignee may pursue any and all
of its  remedies  at law or in equity or any  combination  thereof  against  the
defaulting party.

                16. ESCROW AGREEMENT

                The parties  agree that the Deposit  shall be held by the Escrow
Agent in escrow and disposed of only in accordance  with the  provisions of this
Section  16. The parties  agree that if the Deposit is cash,  such cash shall be
invested in an assignable interest-bearing  certificate of deposit, money market
fund,  treasury bill or other similar  security  approved by Contract Vendee and
Assignee, and all interest accruing thereon shall be paid to Assignee, except as
otherwise provided herein.

                       (a) The Escrow Agent will deliver the Deposit to Contract
Vendee or to Assignee, as the case may be, under the following conditions:

                       (i) To Contract Vendee at Closing;

                       (ii) To Contract  Vendee upon  receipt of written  demand
therefor,  such demand stating that Assignee has defaulted in the performance of
this  Assignment   Agreement  and  specifically  setting  forth  the  facts  and
circumstances  underlying  such  default.  The Escrow Agent shall not honor such
demand until more than five (5) days have elapsed  after  receipt of such demand
by Contract  Vendee or Assignee after  transmittal  by the Escrow Agent,  as the
case may be, nor  thereafter  if the Escrow  Agent shall have  received  written
notice of objection  from Assignee in accordance  with the  provisions of clause
(b) of this Section 16; or

                       (iii)  To  Assignee   upon  receipt  of  written   demand
therefor,  such  demand  stating  that this  agreement  has been  terminated  in
accordance with the provisions  hereof,  or Contract Vendee has defaulted in the
performance of this Assignment  Agreement,  and  specifically  setting forth the
facts and  circumstances  underlying  the same. The Escrow Agent shall not honor
such demand  until more than five (5) days have  elapsed  after  receipt of such
demand to Contract Vendee or Assignee after  transmittal by Escrow Agent, as the
case may be, nor  thereafter,  if the Escrow Agent shall have  received  written
notice of objection  from the other party in accordance  with the  provisions of
clause (b) of this Section 16.

                       (b) Upon the filing of a written  demand for the  Deposit
by Assignee or Contract  Vendee,  pursuant to subclause  (ii) or (iii) of clause
(a) of this Section 16, the Escrow Agent shall  promptly  mail a copy thereof to
the other party.  The other party shall have the right to object to the delivery
of the Deposit by filing  written notice of such objection with the Escrow Agent
at any time within five (5) days after receipt of such copy, but not thereafter.
Such  notice  shall set forth the basis for  objecting  to the  delivery  of the
Deposit.  Upon receipt of such notice,  the Escrow Agent shall  promptly  mail a
copy thereof to the party who filed the written demand.

                       (c) In the event the Escrow Agent shall have received the
notice of objection provided for in clause (b) above and within the time therein
prescribed,  the Escrow Agent shall  continue to hold the Deposit  until (i) the
Escrow Agent receives written notice from Contract Vendee and Assignee directing
the  disbursement  of said Deposit,  in which case,  the Escrow Agent shall then
disburse said Deposit in accordance with said direction, or (ii) in the event of
litigation between Contract Vendee and Assignee,  the Escrow Agent shall deliver
the Deposit to the Clerk of the Court in which said  litigation  is pending,  or
(iii) the Escrow Agent takes such affirmative  steps as the Escrow Agent may, in
the Escrow Agent's  reasonable  opinion,  elect in order to terminate the Escrow
Agent's duties  including,  but not limited to,  depositing the Deposit with the
Court and bringing an action for interpleader,  the costs thereof to be borne by
whichever of Contract Vendee or Assignee is the losing party.

                       (d) The Escrow Agent may act upon any instrument or other
writing  believed  by it in  good  faith  to be  genuine  and to be  signed  and
presented by the proper person and it shall not be liable in connection with the
performance  of any duties  imposed upon the Escrow Agent by the  provisions  of
this Agreement, except for damage caused by the Escrow Agent's own negligence or
willful  default.  The Escrow  Agent  shall  have no duties or  responsibilities
except  those set  forth  herein.  The  Escrow  Agent  shall not be bound by any
modification  of this  agreement,  unless the same is in  writing  and signed by
Assignee and Contract  Vendee,  and, if the Escrow Agent's duties  hereunder are
affected, unless Escrow Agent shall have given prior written consent thereto. In
the event that the Escrow  Agent  shall be  uncertain  as to the Escrow  Agent's
duties or rights  hereunder,  or shall  receive  instructions  from  Assignee or
Contract Vendee which, in the Escrow Agent's  opinion,  are in conflict with any
of the provisions  hereof,  the Escrow Agent shall be entitled to hold and apply
the  Deposit  pursuant  to clause  (c) above and may  decline  to take any other
action.  The  Escrow  Agent  shall not charge a fee for its  services  as escrow
agent.

                17.  NOTICE

                All  notices,  demands,  requests,  or  other  writings  in this
agreement provided to be given or made or sent, or which may be given or made or
sent,  by either  party  hereto to the  other or by  Escrow  Agent,  shall be in
writing  and shall be  delivered  by  depositing  the same  with any  nationally
recognized  overnight delivery service, or by telecopy or fax machine, in either
event with all transmittal  fees prepaid,  properly  addressed,  and sent to the
following addresses:

If to Assignee:                   Cal-Tree Realty Associates L.P.
                                  c/o Cali Realty Acquisition Corporation
                                  11 Commercial Drive
                                  Cranford, New Jersey  07016
                                  Attn: John J. Cali and Roger W. Thomas, Esq.
                                  (908) 272-8000 (tele.)
                                  (908) 272-6755 (fax)

with a copy to:                   Andrew S. Levine, Esq.
                                  Pryor, Cashman, Sherman & Flynn
                                  410 Park Avenue
                                  New York, New York  10022
                                  (212) 326-0414 (tele.)
                                  (212) 326-0806 (fax)

If to Contract Vendee:            J. Brian O'Neill
                                  443 South Gulph Road
                                  King of Prussia, Pennsylvania  19406
                                  (610) 962-5101 (tele.)
                                  (610) 962-5108 (fax)

with a copy to:                   Kevin W. Walsh, Esq.
                                  Adelman Lavine Gold and Levin
                                  Suite 1900
                                  Two Penn Center Plaza
                                  Philadelphia, Pennsylvania  19102
                                  (215) 568-7515 (tele.)
                                  (215) 557-7922 (fax)

If to Escrow Agent:               First American Title Insurance Company
                                  228 East 45th Street
                                  New York, New York 10017
                                  Attention: Escrow Department
                                  (212) 922-9700 (tele.)
                                  (212) 922-0881 (fax)

or to such other  address  as either  party may from time to time  designate  by
written  notice  to the  other  or to the  Escrow  Agent.  Notices  given by (i)
overnight  delivery  service as aforesaid shall be deemed received and effective
on the first  business day  following  such  dispatch  and (ii)  telecopy or fax
machine shall be deemed given at the time and on the date of machine transmittal
provided same is sent prior to 4:00 p.m. on a business day (if sent later,  then
notice shall be deemed given on the next  business day) and if the sending party
receives a written send verification on its machines and forwards a copy thereof
by regular  mail  accompanied  by such notice or  communication.  Notices may be
given by counsel for the parties  described  above,  and such  Notices  shall be
deemed  given by  Assignee  or  Contract  Vendee,  as the  case may be,  for all
purposes hereunder.

                18.    MISCELLANEOUS

                       (a) If any instrument or deposit is reasonably  necessary
in order to  obviate  a defect  in or  objection  or  exception  to  title,  the
following shall apply:  (i) any such instrument  shall be in such form and shall
contain such terms and  conditions  as may be  reasonably  required by the Title
Company to omit any  defect,  objection  or  exception  to title,  (ii) any such
deposit shall be made with the title company,  and (iii) Contract  Vendee agrees
to execute,  acknowledge and deliver, or cause to be executed,  acknowledged and
delivered, any such instrument and to make any such deposit.

                       (b) This  Assignment  Agreement  constitutes  the  entire
agreement  between  the  parties  and  incorporates  and  supersedes  all  prior
negotiations and discussions between the parties.

                       (c) This Assignment  Agreement cannot be amended,  waived
or terminated orally, but only by an agreement in writing signed by the party to
be charged.

                       (d) This  Assignment  Agreement  shall be interpreted and
governed by the laws of the  Commonwealth of  Pennsylvania  and shall be binding
upon the parties hereto and their respective successors and assigns.

                       (e)  Whenever  in this  Assignment  Agreement  there is a
provision  for the  return  of the  Deposit,  the  provision  shall be deemed to
include all interest earned thereon and paid to Assignee.

                       (f) The caption headings in this Assignment Agreement are
for convenience only and are not intended to be part of this agreement and shall
not be  construed  to modify,  explain or alter any of the terms,  covenants  or
conditions herein contained.

                       (g) If any term,  covenant or condition of this agreement
is held to be invalid,  illegal or unenforceable in any respect,  this agreement
shall be construed without such provision.

                       (h)  Each  party  shall,  from  time  to  time,  execute,
acknowledge  and deliver such further  instruments,  and perform such additional
acts,  as the other  party may  reasonably  request in order to  effectuate  the
intent of this agreement.  Nothing contained in this Assignment  Agreement shall
be deemed to create any rights or obligations of  partnership,  joint venture or
similar  association  between  Contract  Vendee and  Assignee.  This  Assignment
Agreement  shall be given a fair and reasonable  construction in accordance with
the  intentions of the parties  hereto,  and without  regard to or aid of canons
requiring  construction  against  Contract  Vendee,  Assignee or the party whose
counsel drafted this agreement.

                       (i) This  Assignment  Agreement shall not be effective or
binding  until such time as it has been  executed  and  delivered by all parties
hereto.  This  Assignment  Agreement  may be executed  by the parties  hereto in
counterparts, all of which together shall constitute a single agreement.

                       (j) This Assignment Agreement shall not create any rights
in any third parties against Assignee not otherwise heretofore in existence.

                IN WITNESS WHEREOF,  the parties have executed this agreement as
of the day and year first above written.

               CONTRACT VENDEE:

                BRYEMERE, L.P.

                          By:   Bryemere Estate Planning and Construction, Inc.


                                 By: _____/s/____________________________
                                       Name: J. Brian O'Neill
                                       Title:



                          ASSIGNEE:

                          CAL-TREE REALTY ASSOCIATES L.P.

                          By:   Cali Sub VIII, Inc.


                          By:   /s/
                              Name: Roger W. Thomas
                              Title: Vice President - General Counsel


ACKNOWLEDGED FOR JOINDER PURPOSES
AS TO SECTIONS 4(a)(vi) and 4(a)(vii) ONLY:

BERWIND PROPERTY GROUP, INC.


By:   /s/
     Name: Stephen M. Spaeder
     Title: Vice President




ESCROW AGENT:

FIRST AMERICAN TITLE INSURANCE COMPANY


By:
     Name:
     Title:

LIST OF EXHIBITS

   Exhibit "A"  -  Property Description

   Exhibit "B"  -  Form of Assignment of Sale and Purchase Agreement, as amended

   Exhibit "C"  -  Sale and Purchase Agreement, as amended

   Exhibit "D"  -  Schedule of Litigation/Proceedings

   Exhibit "E"  -  Additional Leases

   Exhibit "F"  -  Schedule of Leasing Commissions for Renewals or Expansions
                       of Additional Leases

   Exhibit "G"  -  Schedule of Leasing Commissions for Renewals or Expansions of
                      Tenant Leases

   Exhibit "H" -  Economic Terms of the New Leases

   Exhibit "I" -  Tenant Improvements, Brokerage Commissions and Annual
                     Rent under the New Leases





                                   EXHIBIT "A"

                             (Property Description)








                                   EXHIBIT "B"

         (Form of Assignment of Sale and Purchase Agreement, as amended)





                         ASSIGNMENT OF CONTRACT OF SALE

                THIS  ASSIGNMENT  OF CONTRACT OF SALE (the  "Assignment")  dated
this ___ day of April, 1996, made by J. BRIAN O'NEILL, having an address c/o 443
South Gulph Road, King of Prussia, PA 19406 ("Assignor").

                FOR AND IN  CONSIDERATION of Ten ($10.00) Dollars and other good
and  valuable   consideration   paid  by  CAL-TREE  REALTY  ASSOCIATES  L.P.,  a
Pennsylvania  limited partnership having an address c/o Cali Realty Corporation,
11 Commerce Drive, Cranford, New Jersey 07016 ("Assignee") to Assignor,  receipt
of which is acknowledged,  Assignor hereby assigns, sets over and transfers unto
Assignee all of its right,  title and interest in and to that certain  Agreement
of Sale and Purchase  dated as of February 28, 1996,  as amended by that certain
Amendment to Agreement of Sale and Purchase dated April ___, 1996 (collectively,
the  "Agreement")  made by and between  Adwin  Realty  Company,  as seller,  and
Assignor,  as purchaser,  pursuant to which Assignor  agreed to acquire  certain
real property  located at 1400 North Providence  Road,  Media,  Pennsylvania (as
more particularly described in the Agreement).

                TO HAVE AND TO HOLD the same unto  Assignee,  its successors and
assigns forever from and after the effective date of this Assignment.

                IN WITNESS  WHEREOF,  Assignor has executed this  Assignment the
day and year first above written.




                                              --------------------------
                                              J. Brain O'Neill




                                   EXHIBIT "C"

                  (Agreement of Sale and Purchase, as amended)







                                   EXHIBIT "D"

                      (Schedule of Litigation/Proceedings)


                                      None







                                   EXHIBIT "E"

                               (Additional Leases)







                                   EXHIBIT "F"

                (Schedule of Leasing Commissions for Renewals or
                        Expansions of Additional Leases)







                                   EXHIBIT "G"

  (Schedule of Leasing Commissions for Renewals or Expansions of Tenant Leases)







                                   EXHIBIT "H"

                       (Economic Terms of the New Leases)






                                   EXHIBIT "I"

  (Tenant Improvements, Brokerage Commissions and Annual Rent under New Leases)