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                                                                     Exhibit 4.9

                                 THIRD AMENDMENT
                                       TO
                           SECOND AMENDED AND RESTATED
                        AGREEMENT OF LIMITED PARTNERSHIP
                                       OF
                        CABOT INDUSTRIAL PROPERTIES, L.P.

      THIS THIRD AMENDMENT TO SECOND AMENDED AND RESTATED AGREEMENT OF LIMITED
PARTNERSHIP (this "Amendment") dated as of September 27, 1999, is entered into
by CABOT INDUSTRIAL TRUST, a Maryland real estate investment trust, as general
partner (the "General Partner") of CABOT INDUSTRIAL PROPERTIES, L.P. (the
"Partnership"), for itself and on behalf of the limited partners of the
Partnership, and J.P. MORGAN MOSAIC FUND II, LLC, a Delaware limited liability
company ("Contributor").

      WHEREAS, Section 4.2(a) of the Second Amended and Restated Agreement of
Limited Partnership of the Partnership (the "Partnership Agreement") authorizes
the General Partner to cause the Partnership to issue additional Partnership
Units in one or more classes or series, with such designations, preferences and
relative, participating, optional or other special rights, powers and duties as
shall be determined by the General Partner, subject to the provisions of such
section; and

      WHEREAS, pursuant to the authority granted to the General Partner pursuant
to Sections 4.2(a) and 14.1(b) of the Partnership Agreement, the General Partner
desires to amend the Partnership Agreement (i) to establish a new class of
Partnership Units, the Series D Preferred Units (as hereinafter defined), and to
set forth the designations, rights, powers, preferences and ditties of such
Series D Preferred Units, (ii) to issue the Series D Preferred Units to
Contributor and admit Contributor as an Additional Limited Partner and (iii) to
make certain other changes to the Partnership Agreement.

NOW, THEREFORE, in consideration of good and valuable consideration, the receipt
and sufficiency of which hereby are acknowledged, the General Partner hereby
amends the Partnership Agreement as follows:

      Section 1. Definitions. For purposes of this Amendment, the term "Parity
Preferred Units" shall be used to refer to any class or series of Partnership
Interests of the Partnership now or hereafter authorized, issued or outstanding
expressly designated by the Partnership to rank on a parity with Series D
Preferred Units with respect to distributions and rights upon voluntary or
involuntary liquidation, winding-up or dissolution of the Partnership. The term
"Priority Return" shall mean, an amount equal to 8.375% per annum, determined on
the basis of a 360 day year of twelve 30 day months, cumulative to the extent
not distributed for any given distribution period pursuant to Section 5.1 of the
Partnership Agreement, of the stated value of S50 per Series D Preferred Unit,
commencing on the date of issuance of such Series D Preferred Unit. The term
"Subsidiary" shall mean with respect to any person, any corporation,
partnership, limited liability company, joint venture or other entity of which a
majority of(i) voting power of the voting equity securities or (ii) the
outstanding equity interests, is owned, directly or indirectly, by such person.
The term "PTP" shall mean a "publicly traded partnership" within the meaning of
Section 7704 of the Code. Capitalized terms used herein and
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not otherwise defined herein shall have the meanings ascribed to them in the
Partnership Agreement.

      Section 2. Designation and Number. A series of Partnership Units in the
Partnership designated as the "8.375% Series D Cumulative Redeemable Preferred
Units" (the "Series D Preferred Units") is hereby established. The number of
Series D Preferred Units shall be 200,000.

      Section 3. Distributions. (a) Payment of Distributions. Subject to the
rights of holders of Parity Preferred Units as to the payment of distributions,
pursuant to Section 5.1 of the Partnership Agreement, holders of Series D
Preferred Units shall be entitled to receive, when, as and if declared by the
Partnership acting through the General Partner, out of Available Cash,
cumulative preferential cash distributions at the rate per annum of 8.375% of
the original Capital Contribution per Series D Preferred Unit. Such
distributions shall be cumulative, shall accrue from the original date of
issuance and will be payable (i) quarterly in arrears, on March 25, June 25,
September 25 and December 25 of each year commencing on December 25, 1999 and,
(ii), in the event of (A) an exchange of Series D Preferred Units into Series D
Preferred Shares, or (B) a redemption of Series D Preferred Units, on the
exchange date or redemption date, as applicable (each a "Preferred Unit
Distribution Payment Date"). The amount of the distribution payable for any
period will be computed on the basis of a 360-day year of twelve 30-day months
and for any period shorter than a full quarterly period for which distributions
are computed, the amount of the distribution payable will be computed on the
basis of the actual number of days elapsed in such period. If any date on which
distributions are to be made on the Series D Preferred Units is not a Business
Day (as defined herein), then payment of the distribution to be made on such
date will be made on the next succeeding day that is a Business Day (and without
any interest or other payment in respect of any such delay) except that, if such
Business Day is in the next succeeding calendar year, such payment shall be made
on the immediately preceding Business Day, in each case with the same force and
effect as if made on such date. Distributions on the Series D Preferred Units
will be made to the holders of record of the Series D Preferred Units on the
relevant record dates to be fixed by the Partnership acting through the General
Partner, which record dates shall in no event exceed fifteen (15) Business Days
prior to the relevant Preferred Unit Distribution Payment Date (the "Preferred
Unit Partnership Record Date").

      The term "Business Day" shall mean each day other than a Saturday or a
Sunday, which is not a day on which banking institutions in New York, New York
are authorized or required by law, regulations or executive order to close.

            (b) Distributions Cumulative. Distributions on the Series D
Preferred Units will accrue whether or not the terms and provisions of any
agreement of the Partnership, including any agreement relating to its
indebtedness, at any time prohibit the current payment of distributions, whether
or not the Partnership has earnings, whether or not there are funds legally
available for the payment of such distributions and whether or not such
distributions are authorized. Accrued but unpaid distributions on the Series D
Preferred Units will accumulate as of the Preferred Unit Distribution Payment
Date on which they first become payable. Distributions on account of arrears for
any past distribution periods may be declared and paid at any time, without
reference to a regular Preferred Unit Distribution Payment Date to holders of
record of the Series D Preferred Units on the record date fixed by the
Partnership acting through
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the General Partner, which date shall not exceed fifteen (15) Business Days
prior to the payment date. Accumulated and unpaid distributions will not bear
interest.

            (c) Priority as to Distributions. (i) So long as any Series D
Preferred Units are outstanding, no distribution of cash or other property shall
be authorized, declared, paid or set apart for payment on or with respect to any
class or series of Partnership Interests of the Partnership ranking junior as to
the payment of distributions or rights upon a voluntary or involuntary
liquidation, dissolution or winding-up of the Partnership to the Series D
Preferred Units (collectively, "Junior Units"), nor shall any cash or other
property be set aside for or applied to the purchase, redemption or other
acquisition for consideration of any Series D Preferred Units, any Parity
Preferred Units or any Junior Units, unless, in each case, all distributions
accumulated on all Series D Preferred Units and all classes and series of
outstanding Parity Preferred Units have been paid in full. The foregoing
sentence will not prohibit (a) distributions payable solely in Junior Units, (b)
the conversion of Junior Units or Parity Preferred Units into Partnership Units
ranking junior to the Series D Preferred Units as to

            distributions and upon liquidation, winding-up or dissolution or (c)
the redemption of Partnership Interests corresponding to any Series D Preferred
Shares (as hereinafter defined), Parity Preferred Shares (as such term is
defined in the Declaration of Trust of the General Partner, as supplemented (the
"Charter")), or Junior Shares (as such term is defined in the Charter) to be
purchased by the General Partner pursuant to Article 3 of the Charter to
preserve the General Partner's status as a real estate investment trust,
provided that such redemption shall be upon the same terms as the corresponding
purchase pursuant to Article 3 of the Charter.

      (ii) So long as distributions have not been paid in full (or a sum
sufficient for such full payment is not irrevocably deposited in trust for
payment) upon the Series D Preferred Units, all distributions authorized and
declared on the Series D Preferred Units and all classes or series of
outstanding Parity Preferred Units shall be authorized and declared so that the
amount of distributions authorized and declared per Series D Preferred Unit and
such other classes or series of Parity Preferred Units shall in all cases bear
to each other the same ratio that accrued distributions per Series D Preferred
Unit and such other classes or series of Parity Preferred Units (which shall not
include any accumulation in respect of unpaid distributions for prior
distribution periods if such class or series of Parity Preferred Units do not
have cumulative distribution rights) bear to each other.

            (d) No Further Rights. Holders of Series D Preferred Units shall not
be entitled to any distributions, whether payable in cash, other property or
otherwise, in excess of the full cumulative distributions described herein.

      Section 4. Liquidation Proceeds. (a) Upon voluntary or involuntary
liquidation, dissolution or winding-up of the Partnership, distributions on the
Series D Preferred Units shall be made in accordance with Section 13.2 of the
Partnership Agreement.

            (b) Notice. Written notice of any such voluntary or involuntary
liquidation, dissolution or winding-up of the Partnership, stating the payment
date or dates when, and the place or places where, the amounts distributable in
such circumstances shall be payable, shall be given by (i) fax and (ii) by first
class mail, postage pre-paid, not less than thirty (30) and not more than sixty
(60) days prior to the payment date stated therein, to each record holder of the
Series D Preferred Units at the respective addresses of such holders as the same
shall appear on


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the transfer records of the Partnership.

            (c) No Further Rights. After payment of the full amount of the
liquidating distributions to which they are entitled, the holders of Series D
Preferred Units will have no right or claim to any of the remaining assets of
the Partnership.

            (d) Consolidation, Merger or Certain Other Transactions. The
voluntary sale, conveyance, lease, exchange or transfer (for cash, shares of
stock, securities or other consideration) of all or substantially all of the
property or assets of the General Partner to, or the consolidation or merger or
other business combination of the Partnership with or into, any corporation,
trust, partnership, limited liability company or other entity (or of any
corporation, trust, partnership, limited liability company or other entity with
or into the Partnership) shall not be deemed to constitute a liquidation,
dissolution or winding-up of the Partnership.

      Section 5. Optional Redemption. (a) Right of Optional Redemption. The
Series D Preferred Units may not be redeemed prior to the fifth (5th)
anniversary of the issuance date. On or after such date, the Partnership shall
have the right to redeem the Series D Preferred Units, in whole or in part, at
any time or from time to time, upon not less than thirty (30) nor more than
sixty (60) days' written notice, at a redemption price, payable in cash, equal
to the Capital Account balance of the holders of Series D Preferred Units (the
"Redemption Price") provided, however, that no redemption pursuant to this
Section 5 will be permitted if the Redemption Price does not equal or exceed the
original Capital Contribution of such holder plus the cumulative Priority
Return, whether or not declared, to the redemption date to the extent not
previously distributed or distributed pursuant to Section 3(a). If fewer than
all of the outstanding Series D Preferred Units are to be redeemed, the Series D
Preferred Units to be redeemed shall be selected pro rata (as nearly as
practicable without creating fractional units).

            (b) Limitation on Redemption. The Partnership may not redeem fewer
than all of the outstanding Series D Preferred Units unless all accumulated and
unpaid distributions have been paid on all Series D Preferred Units for all
quarterly distribution periods terminating on or prior to the date of
redemption.

            (c) Procedures for Redemption. (i) Notice of redemption will be (A)
faxed, and (B) mailed by the Partnership, by certified mail, postage prepaid,
not less than thirty (30) nor more than sixty (60) days prior to the redemption
date, addressed to the respective holders of record of the Series D Preferred
Units at their respective addresses as they appear on the records of the
Partnership. No failure to give or defect in such notice shall affect the
validity of the proceedings for the redemption of any Series D Preferred Units
except as to the holder to whom such notice was defective or not given. In
addition to any information required by law, each such notice shall state: (1)
the redemption date, (2) the Redemption Price, (3) the aggregate number of
Series D Preferred Units to be redeemed and if fewer than all of the outstanding
Series D Preferred Units are to be redeemed, the number of Series D Preferred
Units to be redeemed held by such holder, which number shall equal such holder's
pro rata share (based on the percentage of the aggregate number of outstanding
Series D Preferred Units the total number of Series D Preferred Units held by
such holder represents) of the aggregate number of Series D Preferred Units to
be redeemed, (4) the place or places where such Series D Preferred Units are to
be surrendered for payment of the Redemption Price, (5) that distributions on
the Series D Preferred Units to be redeemed will cease to accumulate on such
redemption date and (6) that payment of the Redemption Price will be made upon
presentation and surrender of such Series D


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Preferred Units.

      (ii) If the Partnership gives a notice of redemption in respect of Series
D Preferred Units (which notice will be irrevocable) then, by 12:00 noon, New
York City time, on the redemption date, the Partnership will deposit irrevocably
in trust for the benefit of the Series D Preferred Units being redeemed funds
sufficient to pay the applicable Redemption Price and will give irrevocable
instructions and authority to pay such Redemption Price to the holders of the
Series D Preferred Units upon surrender of the Series D Preferred Units by such
holders at the place designated in the notice of redemption. If the Series D
Preferred Units are evidenced by a certificate and if fewer than all Series D
Preferred Units evidenced by any certificate are being redeemed, a new
certificate shall be issued upon surrender of the certificate evidencing all
Series D Preferred Units, evidencing the unredeemed Series D Preferred Units
without cost to the holder thereof. On and after the date of redemption,
distributions will cease to accumulate on the Series D Preferred Units or
portions thereof called for redemption, unless the Partnership defaults in the
payment thereof. If any date fixed for redemption of Series D Preferred Units is
not a Business Day, then payment of the Redemption Price payable on such date
will be made on the next succeeding day that is a Business Day (and without any
interest or other payment in respect of any such delay) except that, if such
Business Day falls in the next calendar year, such payment will be made on the
immediately preceding Business Day, in each case with the same force and effect
as if made on such date fixed for redemption. If payment of the Redemption Price
is improperly withheld or refused and not paid by the Partnership, distributions
on such Series D Preferred Units will continue to accumulate from the original
redemption date to the date of payment, in which case the actual payment date
will be considered the date fixed for redemption for purposes of calculating the
applicable Redemption Price.

      Section 6. Voting Rights. (a) General. Holders of the Series D Preferred
Units will not have any voting rights or right to consent to any matter
requiring the consent or approval of the Limited Partners, except as set forth
in the Partnership Agreement and except as set forth below. In the event of a
conflict between the terms of this Section 6 and any other terms of this
Amendment, the terms of this Section 6 shall control.

            (b) Certain Voting Rights. So long as any Series D Preferred Units
remain outstanding, the Partnership shall not, without the affirmative vote of
the holders of at least two-thirds of the Series D Preferred Units outstanding
at the time (i) authorize or create, or increase the authorized or issued amount
of, any class or series of Partnership Interests senior to the Series D
Preferred Units with respect to payment of distributions or rights upon
liquidation, dissolution or winding-up of the Partnership or reclassify any
Partnership Interests of the Partnership into any such senior Partnership
Interests, or create, authorize or issue any obligations or security convertible
into or evidencing the right to purchase any such senior Partnership Interests,
(ii) authorize or create, or increase the authorized or issued amount of any
Parity Preferred Units or reclassify any Partnership Interest into any such
Partnership Interest or create, authorize or issue any obligations or security
convertible into or evidencing the right to purchase any such Partnership
Interests but only to the extent such Parity Preferred Units are issued to an
Affiliate of the Partnership, other than the General Partner to the extent the
issuance of such interests was to allow the General Partner to issue
corresponding preferred stock to persons who are not Affiliates of the
Partnership (or to Affiliates purchasing the preferred stock on the same terms
as non-affiliated purchasers) or (iii) either (A) consolidate, merge into or
with,


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or convey, transfer or lease all or substantially all of its assets to, any
corporation or other entity or (B) amend, alter or repeal the provisions of the
Partnership Agreement whether by merger, consolidation or otherwise, that would
materially and adversely affect the powers, special rights, preferences,
privileges or voting power of the Series D Preferred Units or the holders
thereof, provided, however, that with respect to the occurrence of a merger,
consolidation or a sale or lease of all or substantially all of the
Partnership's assets as an entirety, so long as (1) the Partnership is the
surviving entity and the Series D Preferred Units remain outstanding with the
terms thereof unchanged, or (2) the resulting, surviving or transferee entity is
a partnership, limited liability company or other pass-through entity organized
under the laws of any state and substitutes the Series D Preferred Units for
other interests in such entity having substantially the same terms and rights as
the Series D Preferred Units, including with respect to distributions, voting
rights and rights upon liquidation, dissolution or winding-up of the
Partnership, then the occurrence of any such event shall not be deemed to
materially and adversely affect such rights, privileges or voting powers of the
holders of the Series D Preferred Units and no vote of the Series D Preferred
Units shall be required in such case; and provided further that any increase in
the amount of Partnership Interests or the creation or issuance of any other
class or series of Partnership Interests, in each case ranking (y) junior to the
Series D Preferred Units with respect to payment of distributions or the
distribution of assets upon liquidation, dissolution or winding-up of the
Partnership, or (z) on a parity with the Series D Preferred Units with respect
to payment of distributions and the distribution of assets upon liquidation,
dissolution or winding-up of the Partnership to the extent such Partnership
Interests are not issued to an Affiliate, other than the General Partner to the
extent the issuance of such interests was to allow the General Partner to issue
corresponding preferred stock to persons who are not Affiliates, shall not be
deemed to materially and adversely affect such rights, preferences, privileges
or voting powers and no vote of the Series D Preferred Units shall be required
in such case.

      Section 7. Transfer Restrictions. The Series D Preferred Units shall be
subject to the provisions of Article XI of the Partnership Agreement, provided,
however, that (i) the General Partner shall act reasonably in exercising its
discretion pursuant to the provisions of Section 11.4(a)(ii) to transferees of
Series D Preferred Units, (ii) the provisions of Clause B of Section 11.3(d)
shall not be applicable to holders of Series D Preferred Units if at the time of
such transfer, the Partnership already has 100 Partners; (iii) if only a portion
of the Series D Preferred Units shall be transferred, the transferee of such
transferred Series D Preferred Units shall, subject to the provisions of Section
11.4, be substituted as a Limited Partner in place of the transferring holders
only as to the Series D Preferred Units so transferred; and (iv) the provisions
of Sections 11.6(c) and 11.6(d) shall not be applicable to any transfer of
Series D Preferred Units; and provided further that "transfer" when used in
Article XI shall not be deemed to include any exchange pursuant to Section 8
below.

      Section 8. Exchange Rights. (a) Right to Exchange. (i) Series D Preferred
Units will be exchangeable in whole or in part at anytime on or after the tenth
(10th) anniversary of the date of issuance, at the option of the holders
thereof, for authorized but previously unissued shares of 8.375% Series D
Cumulative Redeemable Preferred Shares of the General Partner (the "Series D
Preferred Shares") at an exchange rate of one Series D Preferred Share for one
Series D Preferred Unit, subject to adjustment as described below (the "Exchange
Price"), provided that the Series D Preferred Units will become exchangeable at
any time, in whole or in part, at the


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option of the holders of Series D Units, for Series D Preferred Shares if (y) at
any time full distributions shall not have been timely made on any Series D
Preferred Unit with respect to six (6) prior quarterly distribution periods,
whether or not consecutive; provided, however, that a distribution in respect of
Series D Preferred Units shall be considered timely made if made within two (2)
Business Days after the applicable Preferred Unit Distribution Payment Date if
at the time of such late payment there shall not be any prior quarterly
distribution periods in respect of which full distributions were not timely made
or (z) upon receipt by a holder or holders of Series D Preferred Units of (1) a
notice from the General Partner that the General Partner or a Subsidiary of the
General Partner has taken the position that the Partnership is, or upon the
occurrence of a defined event in the immediate future will be, a PTP and (2) an
opinion rendered by an outside nationally recognized independent counsel
familiar with such matters addressed to a holder or holders of Series D
Preferred Units, that the Partnership is or likely is, or upon the occurrence of
a defined event in the immediate future will be or likely will be, a PTP. In
addition, the Series D Preferred Units may be exchanged for Series D Preferred
Shares, in whole or in part, at the option of any holder prior to the tenth
(10th) anniversary of the issuance date and after the third (3rd) anniversary
thereof if such holder of a Series D Preferred Units shall deliver to the
General Partner either (i) a private letter ruling addressed to such holder of
Series D Preferred Units or (ii) an opinion of independent counsel reasonably
acceptable to the General Partner based on the enactment of a statute, temporary
or final Treasury Regulations or the publication of a Revenue Ruling, in either
case to the effect that an exchange of the Series D Preferred Units at such
earlier time would not cause the Series D Preferred Units to be considered
"stock or securities" within the meaning of Section 351(e) of the Code for
purposes of determining whether the holder of such Series D Preferred Units is
an "investment company" under Section 721(b) of the Code if an exchange is
permitted at such earlier date. Furthermore, all the Series D Preferred Units,
held by any holder thereof which is a real estate investment trust within the
meaning of Sections 856 through 859 of the Code for Series D Preferred Shares
may be exchanged in whole but not in part (but only if the exchange may be
accomplished consistently with the ownership limitations set forth under Article
3 of the Charter (taking into account exceptions thereto)) if at any time, (i)
the Partnership reasonably determines that the assets and income of the
Partnership for a taxable year after 1999 would not satisfy the income and
assets tests of Section 856 of the Code for such taxable year if the Partnership
were a real estate investment trust within the meaning of the Code or (ii) any
such holder of Series B Preferred Units shall deliver to the Partnership and the
General Partner an opinion of independent counsel reasonably acceptable to the
General Partner to the effect that, based on the assets and income of the
Partnership for a taxable year after 1999, the Partnership would not satisfy the
income assets tests of Section 856 of the Code for such taxable year if the
Partnership were a real estate investment trust within the meaning of the Code
and that such failure would create a meaningful risk that a holder of the Series
B Preferred Units would fail to maintain qualification as a real estate
investment trust.

      (ii) Notwithstanding anything to the contrary set forth in Section 8(a)(i)
hereof, if an Exchange Notice (as defined herein) has been delivered to the
General Partner, then the General Partner may, at its option, elect to redeem or
cause the Partnership to redeem all or a portion of the outstanding Series D
Preferred Units for cash in an amount equal to the original Capital Contribution
per Series D Preferred Unit and all accrued and unpaid distributions thereon to
the


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date of redemption. The General Partner may exercise its option to redeem the
Series D Preferred Units for cash pursuant to this Section 8(a)(ii) hereof by
giving each holder of record of Series D Preferred Units notice of its election
to redeem for cash, within ten (10) Business Days after receipt of the Exchange
Notice, by (y) fax, and (z) registered mail, postage paid, at the address of
each holder as it may appear on the records of the Partnership stating (A) the
redemption date, which shall be no later than sixty (60) days following the
receipt of the Exchange Notice, (B) the redemption price, (D) the place or
places where the Series D Preferred Units are to be surrendered for payment of
the redemption price, (D) that distributions on the Series D Preferred Units
will cease to accrue on such redemption date; (E) that payment of the redemption
price will be made upon presentation and surrender of the Series D Preferred
Units and (F) the aggregate number of Series D Preferred Units to be redeemed,
and if fewer than all of the outstanding Series D Preferred Units are to be
redeemed, the number of Series D Preferred Units to be redeemed held by such
holder, which number shall equal such holder's pro-rata share (based on the
percentage of the aggregate number of outstanding Series D Preferred Units the
total number of Series D Preferred Units held by such holder represents) of the
aggregate number of Series D Preferred Units being redeemed.

      (iii) In the event an exchange of all or a portion of Series D Preferred
Units pursuant to Section 8(a)(i) hereof would violate the provisions on
ownership limitation of the General Partner set forth in Article 3 of the
Charter with respect to the Series D Preferred Shares, the General Partner shall
give written notice thereof to each holder of record of Series D Preferred
Units, within ten (10) Business Days following receipt of the Exchange Notice,
by (y) fax, and (z) registered mail, postage prepaid, at the address of each
such holder set forth in the records of the Partnership. In such event, each
holder of Series D Preferred Units shall be entitled to exchange, pursuant to
the provision of Section 8(b) a number of Series D Preferred Units which would
comply with the provisions on the ownership limitation of the General Partner
set forth in such Article 3 of the Charter and any Series D Preferred Units not
so exchanged (the "Excess Units") shall be redeemed by the Partnership for cash
in an amount equal to the original Capital Contribution per Excess Unit, plus
any accrued and unpaid distributions thereon, whether or not declared, to the
date of redemption. The written notice of the General Partner shall state (A)
the number of Excess Units held by such holder, (B) the redemption price of the
Excess Units, (D) the date on which such Excess Units shall be redeemed, which
date shall be no later than sixty (60) days following the receipt of the
Exchange Notice, (D) the place or places where such Excess Units are to be
surrendered for payment of the Redemption Price, (E) that distributions on the
Excess Units will cease to accrue on such redemption date, and (F) that payment
of the redemption price will be made upon presentation and surrender of such
Excess Units. In the event an exchange would result in Excess Units, as a
condition to such exchange, each holder of such units agrees to provide
representations and covenants reasonably requested by the General Partner
relating to (1) the widely held nature of the interests in such holder,
sufficient to assure the General Partner that the holder's ownership of stock of
the General Partner (without regard to the limits described above) will not
cause any individual to Beneficially Own in excess of the Ownership Limit (all
as defined in the General Partner's Charter); and (2) to the extent such holder
can so represent and covenant without obtaining information from its owners, the
holder's ownership of tenants of the Partnership and its affiliates.


                                       8
<PAGE>

      (iv) The redemption of Series D Preferred Units described in Section
8(a)(ii) and (iii) shall be subject to the provisions of Sections 5(b) and
5(c)(ii); provided, however, that the term "Redemption Price" in such section
shall be read to mean the original Capital Contribution per Series D Preferred
Unit being redeemed plus all accrued and unpaid distributions to the redemption
date.

            (b) Procedure for Exchange. (i) Any exchange pursuant to this
Amendment shall be exercised pursuant to a notice of exchange (the "Exchange
Notice") delivered to the General Partner by the holder who is exercising such
exchange right, by (A) fax and (B) by certified mail postage prepaid. The
exchange of Series D Preferred Units, or a specified portion thereof, may be
effected after the fifth (5th) Business Day following receipt by the General
Partner of the Exchange Notice by delivering certificates, if any, representing
such Series D Preferred Units to be exchanged together with, if applicable,
written notice of exchange and a proper assignment of such Series D Preferred
Units to the office of the General Partner maintained for such purpose.
Currently, such office is Two Center Plaza, Suite 200, Boston, Massachusetts
02108. Each exchange will be deemed to have been effected immediately prior to
the close of business on the date on which such Series D Preferred Units to be
exchanged (together with all required documentation) shall have been surrendered
and notice shall have been received by the General Partner as aforesaid and the
Exchange Price shall have been paid. Any Series D Preferred Shares issued
pursuant to this Section 8 shall be delivered as shares which are duly
authorized, validly issued, fully paid and nonassessable, free of pledge, lien,
encumbrance or restriction other than those provided in the Charter, the Bylaws
of the General Partner, the Securities Act of 1933 and relevant state securities
or blue sky laws.

      (ii) In the event of an exchange of Series D Preferred Units for Series D
Preferred Shares, an amount equal to the accrued and unpaid distributions,
whether or not declared, to the date of exchange on any Series D Preferred Units
tendered for exchange shall (A) accrue on the Series D Preferred Shares into
which such Series D Preferred Units are exchanged, and (B) continue to accrue on
such Series D Preferred Units, which shall remain outstanding following such
exchange, with the General Partner as the holder of such Series D Preferred
Units. Notwithstanding anything to the contrary set forth herein, in no event
shall a holder of a Series D Preferred Unit that was validly exchanged into
Series D Preferred Shares pursuant to this section (other than the General
Partner now holding such Series D Preferred Unit), receive a cash distribution
out of Available Cash of the Partnership, if such holder, after exchange, is
entitled to receive a distribution out of Available Cash with respect to the
Series D Preferred Shares for which such Series D Preferred Unit was exchanged
or redeemed.

            (iii) Fractional shares of Series D Preferred Shares are not to be
issued upon exchange but, in lieu thereof, the General Partner will pay a cash
adjustment based upon the fair market value of the Series D Preferred Shares on
the day prior to the exchange date as determined in good faith by the Board of
Directors of the General Partner.

            (c) Adjustment of Exchange Price. (i) The Exchange Price is subject
to adjustment upon certain events, including (a) subdivisions, combinations and
reclassifications of the Series D Preferred Shares and (b) distributions to all
holders of Series D Preferred Shares of evidences of indebtedness of the General
Partner or assets (including securities but excluding dividends and
distributions paid out of equity applicable to Series D Preferred Shares).

      (ii) In case the General Partner shall be a party to any transaction
(including,


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<PAGE>

without limitation, a merger, consolidation, statutory share exchange, tender
offer for all or substantially all of the General Partner's capital stock or
sale of all or substantially all of the General Partner's assets), in each case
as a result of which the Series D Preferred Shares will be converted into the
right to receive shares of capital stock, other securities or other property
(including cash or any combination thereof), each Series D Preferred Unit will
thereafter be exchangeable into the kind and amount of shares of capital stock
and other securities and property receivable (including cash or any combination
thereof) upon the consummation of such transaction by a holder of that number of
Series D Preferred Shares or fraction thereof into which one Series D Preferred
Unit was exchangeable immediately prior to such transaction. The General Partner
may not become a party to any such transaction unless the terms thereof are
inconsistent with the foregoing.

      Section 9. No Conversion Rights. (a) The holders of the Series D Preferred
Units shall not have any rights to convert such Partnership Units into any other
class of Partnership Interests or any interest in the Partnership;

      (b) The Series D Preferred Units shall not be subject to the provisions of
Section 4.2(e) of the Partnership Agreement.

      Section 10. No Sinking Fund. No sinking fund shall be established for the
retirement or redemption of the Series D Preferred Units.

      Section 11. Admission of Limited Partner; Exhibits to Partnership
Agreement. In accordance with Section 12.2(b), Contributor is hereby admitted as
an Additional Limited Partner. In order to duly reflect the issuance of Series D
Preferred Units provided for herein, the Partnership Agreement will be amended
by deleting Exhibit A attached thereto and substituting Exhibit A attached
hereto therefor.

      Section 12. Reaffirmation. Except as modified herein, all terms and
conditions of the Partnership Agreement shall remain in full force and effect,
which terms and conditions the General Partner hereby ratifies and affirms.


                                       10
<PAGE>

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IN WITNESS WHEREOF, this Amendment has been executed as of the date first above
written.


CABOT INDUSTRIAL TRUST

By: ____________________
Name:  Neil Waisnor
Title: Senior Vice President


                     ***Signatures Continued On Next Page***
<PAGE>

                                    J.P. MORGAN MOSAIC FUND II, LLC

                                    By: J.P. Morgan Private Investments Inc., as
                                        manager of J.P. Morgan Fund II, LLC

                          By:___________________________________
                                           Name:
                                           Title:

                                    Address:


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