Exhibit 4.2

                                                               Execution Version















                          SECOND SUPPLEMENTAL INDENTURE

                           Dated as of August 13, 2002

                                     between

                     IROQUOIS GAS TRANSMISSION SYSTEM, L.P.

                                       and

                               JPMORGAN CHASE BANK
                  (formerly known as The Chase Manhattan Bank),

                as Trustee, Paying Agent, Security Registrar and

                                 Transfer Agent






                           6.10% Senior Notes Due 2027



<PAGE>


         SECOND SUPPLEMENTAL INDENTURE, dated as of August 13, 2002 (this
"Second Supplemental Indenture"), between IROQUOIS GAS TRANSMISSION SYSTEM,
L.P., a limited partnership organized under the laws of the State of Delaware,
as issuer (the "Issuer") and JPMORGAN CHASE BANK (formerly known as THE CHASE
MANHATTAN BANK), as Trustee, Paying Agent, Security Registrar and Transfer Agent
under the Original Indenture referred to below (the "Trustee").

                                   WITNESSETH:

         WHEREAS, the Issuer has heretofore executed and delivered to the
Trustee an indenture dated as of May 30, 2000 (hereinafter called the "Original
Indenture", and together with this Second Supplemental Indenture, the
"Indenture") to provide for the issuance from time to time of certain of its
debt securities;

         WHEREAS, Section 9.1 of the Original Indenture provides, among other
things, that the Issuer and the Trustee may enter into indentures supplemental
to the Original Indenture without the consent of any Holders, among other
things, (i) for the purpose of establishing the form and terms of any series of
its debt securities as permitted by Section 2.1 of the Original Indenture and/or
(ii) to add to, change or eliminate any provision of the Original Indenture
subject to compliance with the requirements of Section 9.1(j) thereof;

         WHEREAS the Issuer desires to create, pursuant to Section 2.1 of the
Original Indenture, a series of debt securities in an aggregate principal amount
of $170,000,000 to be designated the "6.10% Senior Notes Due 2027" (such debt
securities, as issued on August 13, 2002, the "Notes", which shall constitute
"Notes" for the purposes of the Original Indenture and this Second Supplemental
Indenture but the use of the term "Notes" in this Second Supplemental Indenture
shall (except as otherwise expressly provided in the Original Indenture or
herein or unless the context otherwise requires) refer only to the Notes issued
pursuant to this Second Supplemental Indenture), and all actions on the part of
the Issuer necessary to authorize the issuance of the Notes under the Original
Indenture and this Second Supplemental Indenture have been duly taken; and

         WHEREAS, all acts and things necessary to make such Notes, when
executed by the Issuer and authenticated and delivered by the Trustee as
provided in the Original Indenture, the valid and binding obligations of the
Issuer and to constitute these presents a valid and binding supplemental
indenture and agreement according to its terms, have been duly done and
performed.


<PAGE>

         NOW, THEREFORE, THIS SECOND SUPPLEMENTAL INDENTURE WITNESSETH:

         That in consideration of the premises and of the acceptance and
purchase of the Notes by the holders thereof and of the acceptance of this trust
by the Trustee, the Issuer covenants and agrees with the Trustee, for the equal
benefit of holders of the Notes, as follows:

                                  Article One
                                   Definitions

         The use of the terms and expressions herein is in accordance with the
definitions, uses and constructions contained in the Original Indenture and the
form of the Note attached hereto as Exhibit A. The terms used in this Second
Supplemental Indenture, or the Original Indenture as they relate to the Notes,
which are not defined in the Original Indenture or this Second Supplemental
Indenture but which are defined in the Trust Indenture Act, or which are by
reference in the Trust Indenture Act defined in the Securities Act (except as
otherwise expressly provided in the Indenture or unless the context otherwise
requires), shall have the meanings assigned to such terms under the Trust
Indenture Act and in the Securities Act as in force at the date of the execution
of this Second Supplemental Indenture. In addition, for all purposes of this
Second Supplemental Indenture, except as otherwise expressly provided or unless
the context otherwise expressly requires, the following terms shall have the
respective meanings assigned to them as follows and shall be construed as if
defined in Article One of the Original Indenture:

         "Athens Expansion" means the addition of compression capacity and
facilities by the Issuer to service the 1,080 MW Athens Power Station in Athens,
New York.

         "DTC" means The Depository Trust Company, New York, New York, or its
successors.

         "Eastchester Extension" means (i) the addition of compression capacity
and gas cooling facilities by the Issuer at multiple new and existing
compression station facilities located in New York along the Pipeline and (ii) a
pipeline of the Issuer from Northport, Long Island westward through the Long
Island Sound and East River to the Hunts Point section of New York City.

         "First Supplemental Indenture" mean that First Supplemental Indenture
dated as of May 30, 2000 executed and delivered by the Issuer and the Trustee.

         "Regulation S" means Regulation S under the Securities Act, as such
Regulation may be amended from time to time, or under any similar rules or
regulations hereafter adopted by the SEC.

         "Restricted Notes Legend" means a legend substantially in the form of
the legend identified as such and contained in the form of Notes set forth in
Exhibit A hereto.



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<PAGE>

         "Transfer Certificate" means a certificate of transfer satisfactory to
the Issuer and the Trustee (as Security Registrar) substantially in the form of
Exhibit B hereto.

                                  Article Two
                         Terms and Issuance of the Notes

Section 2.1. Issue of Notes.

         Each of the Notes shall be executed, authenticated and delivered in
accordance with the provisions of, and shall in all respects be subject to, the
terms, conditions and covenants of the Original Indenture and this Second
Supplemental Indenture (including the form of Note set forth in Exhibit A
attached hereto). The aggregate principal amount of the Notes which may be
authenticated and delivered under this Second Supplemental Indenture shall not
exceed $170,000,000.

Section 2.2. Interest; Principal; Record Date.

         Interest on the Notes will be payable semi-annually on April 30 and
October 31 in each year, commencing April 30, 2003, at a rate of 6.10% per
annum, until the principal thereof is paid or made available for payment.

         Principal on the Notes will be payable semi-annually on April 30 and
October 31 in each year, commencing April 30, 2008, in accordance with the
amortization schedule attached to this Second Supplemental Indenture as Exhibit
C and to each Note.

         The interest and principal so payable, and punctually paid or duly
provided for, on any Debt Service Payment Date will be paid to the Person in
whose name the Notes (or one or more Predecessor Notes) are registered at the
close of business on the Regular Record Date for such principal and interest,
which shall be the fifteenth day (whether or not a Business Day) preceding such
Debt Service Payment Date.

         Any such interest or principal not so punctually paid or duly provided
for will forthwith cease to be payable to the Person in whose name the Notes are
registered on the Regular Record Date and may be paid to the Person in whose
name such Notes (or one or more Predecessor Notes) are registered at the close
of business on the Special Record Date to be fixed by the Issuer, notice whereof
shall be given to the Holders of the Notes not less than 10 days prior to such
Special Record Date, or may be paid at any time in any other lawful manner not
inconsistent with the requirements of any securities exchange on which the Notes
may be listed and upon such notice as may be required by such exchange on which
the Notes may be listed, and upon such notice as may be required by such
exchange, all as more fully provided in the Original Indenture. The Notes do not
have the benefit of any sinking fund, but the principal amount thereof shall
amortize as set forth above and in each Note.



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<PAGE>

Section 2.3. Place of Payment.

         The principal of, the premium, if any, and interest on the Notes will
be payable at the offices of the Trustee at: 450 West 33rd Street, New York, New
York 10001, Attention: Institutional Trust Services (the "Place of Payment").

         The Notes may be surrendered for registration of transfer and exchange
at the Place of Payment. Upon receiving the Notes surrendered for registration
of transfer or exchange, the Issuer will issue new Notes which will be sent to
the Trustee for authentication and delivery as set forth in Section 2.5 of this
Second Supplemental Indenture. Notices and demands to or upon the Issuer in
respect of the Notes may be served at the Place of Payment.

Section 2.4. Form of the Notes; Incorporation of Terms.

         The Notes offered and sold in their initial distribution in reliance on
Rule 144A shall initially be issued in the form of one or more separate Global
Notes (each, a "Rule 144A Global Note"), the face and reverse of which shall be
substantially in the form set forth in Exhibit A attached hereto, the terms of
which are herein incorporated by reference and which are part of this Second
Supplemental Indenture. The Notes offered and sold in their initial distribution
in reliance on Regulation S shall initially be issued in the form of one or more
separate Global Notes (each, a "Regulation S Global Note", and together with all
Rule 144A Global Notes, the "Global Notes"), the face and reverse of which shall
be substantially in the form set forth in Exhibit A attached hereto. Definitive
Notes registered in the name or names of Persons other than the Depositary or
its nominee shall only be issued in exchange for any Global Note in the
circumstances set forth in Section 2.4(b)(ii) of the Original Indenture and
shall be substantially in the form set forth in Exhibit A attached hereto.

Section 2.5. Transfer Restrictions; Exchange of Notes.

         The Notes, as originally issued under this Second Supplemental
Indenture, are restricted and may not be transferred except in compliance with
the Restricted Notes Legend. The Notes shall bear the Restricted Notes Legend
until such time as such Restricted Notes Legend shall be removed by the Issuer
(i) in the case of any Note issued pursuant to Rule 144A, at any time on or
after the occurrence of the "Resale Restriction Termination Date" on such Legend
and (ii) in the case of any Note issued pursuant to Regulation S at any time on
or after the expiration of the "restricted period" (within the meaning of
Regulation S) with respect to any such Note. The Issuer shall notify the Trustee
of the expiration date of the "restricted period".

         (a) Exchanges between Regulation S Global Note and Rule 144A Global
Note.

         If a holder of a beneficial interest in a Rule 144A Global Note wishes
at any time to transfer such interest to a Person who wishes to take delivery
thereof in the form of a beneficial interest in a Regulation S Global Note, or
if a holder of a beneficial interest in a Regulation S Global Note wishes at any
time to transfer such interest to a



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<PAGE>

Person who wishes to take delivery thereof in the form of a beneficial interest
in a Rule 144A Global Note, upon receipt by the Trustee (as Security Registrar)
at its Corporate Trust Office of a Transfer Certificate in the appropriate form
and:

          (i) written instructions given in accordance with the rules and
     procedures of the Depositary (together with, as applicable, the rules and
     procedures of Euroclear Bank S.A./N.V. ("Euroclear") and Clearstream
     Banking, societe anonyme ("Clearstream, Luxembourg"), the "Applicable
     Procedures") from the respective Person who has an account with the
     Depositary (each such Person, a "Participant") directing the Depositary to
     cause to be credited to the account of another Participant a beneficial
     interest in such Regulation S Global Note or Rule 144A Global Note (as the
     case may be) equal to that of the beneficial interest in such Rule 144A
     Global Note or Regulation S Global Note (as the case may be) to be so
     transferred; and

          (ii) written instructions given in accordance with the Applicable
     Procedures containing information regarding such other account, as well as
     the account of Euroclear or Clearstream, Luxembourg (as the case may be)
     for which such other account is held, to be credited with, and the account
     of such applicable Participant to be debited for, such beneficial interest;

the Trustee shall (1) reduce or increase (as the case may be) the principal
amount of such Rule 144A Global Note, and increase or reduce (as the case may
be) the principal amount of such Regulation S Global Note, in each case by an
amount equal to the principal amount of the beneficial interest in such Rule
144A Global Note or Regulation S Global Note (as the case may be) to be so
transferred, (2) instruct the Depositary to make a corresponding reduction or
increase (as the case may be) to the book-entry interests relating to such
Global Note and to credit and debit such beneficial interests to the respective
accounts specified in the instructions referred to above.

         (b) Exchanging Restricted Definitive Notes for Regulation S Global Note
or Rule 144A Global Note.

         If a holder of a Definitive Note bearing the Restricted Note Legend
(the "Restricted Definitive Note") wishes to exchange all or part of such
Definitive Note for a beneficial interest in a Regulation S Global Note or a
beneficial interest in a Rule 144A Global Note or wishes to transfer all or part
of such Restricted Definitive Note to a person who wishes to take delivery
thereof in the form of a beneficial interest in a Regulation S Global Note or a
Rule 144A Global Note, upon receipt by the Trustee (as Security Registrar) at
its Corporate Trust Office of a Transfer Certificate in the appropriate form
and:

          (i) the Restricted Definitive Note to be so exchanged or transferred;
     and

          (ii) written instructions given in accordance with the rules and
     procedures of the Depositary and the Applicable Procedures from the
     applicable



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<PAGE>

     Participant directing the Trustee to cancel such Restricted Definitive Note
     (or part thereof being transferred, so long as the part not being
     transferred is in the principal amount of authorized denominations of such
     Restrictive Definitive Note, in which case the Trustee shall issue a new
     Restricted Definitive Note to the original Holder in the aggregate original
     principal of the original Restricted Definitive Note not being so
     transferred) and for the Depositary to cause to be credited to the
     specified account of the applicable Participant a beneficial interest in
     such Regulation S Global Note or Rule 144A Global Note (as the case may be)
     equal to the principal amount of the Restricted Definitive Note so
     exchanged or transferred;

the Trustee shall (1) cancel such Restricted Definitive Note (or part thereof
being transferred, so long as the part not being transferred is in the principal
amount of authorized denominations of such Restrictive Definitive Note, in which
case the Trustee shall issue a new Restricted Definitive Note to the original
Holder in the aggregate original principal of the original Restricted Definitive
Note not being so transferred) and (2) instruct the Depositary to make a
corresponding increase to the book-entry interests relating to such Regulation S
Global Note or Rule 144A Global Note (as the case may be) and to credit such
beneficial interests to the respective accounts specified in the instructions
referred to above.

         (c) Exchange of Regulation S Global Note or Rule 144A Global Note for
Definitive Notes.

         Subject to compliance with Section 2.4(b)(ii) of the Original Indenture
(other than clause (C) of such Section 2.4(b)(ii), which clause (C) shall not be
applicable to the Notes), if a holder of a beneficial interest in a Regulation S
Global Note or a Rule 144A Global Note is required to exchange such interest for
one or more Restricted Definitive Notes or to transfer such interest to a person
who is required to take delivery thereof in the form of one or more Restricted
Definitive Notes, upon receipt by the Trustee (as Security Registrar) at its
Corporate Trust Office of a Transfer Certificate in the appropriate form and:

          (i) written instructions given in accordance with the rules and
     procedures of the Depositary and the Applicable Procedures from the
     applicable Participant directing the Trustee to authenticate and deliver
     such Definitive Note or Notes in an aggregate principal equal to that of
     the beneficial interest in the Regulation S Global Note or Rule 144A Global
     Note (as the case may be) to be debited and for the Depositary to cause to
     be debited to the specified account of the applicable Participant a
     beneficial interest in such Regulation S Global Note or Rule 144A Global
     Note (as the case may be) equal to the principal amount of the Restricted
     Definitive Note so exchanged or transferred; such information to contain
     the name in which such Restricted Definitive Note or Notes are to be
     registered and the authorized denomination of each such Restricted
     Definitive Note or Notes; and

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<PAGE>

          (ii) one or more Restricted Definitive Notes issued and duly executed
     by the Issuer;

the Trustee shall (1) instruct the Depositary to make a corresponding reduction
to the book-entry interests relating to such Regulation S Global Note or Rule
144A Global Note (as the case may be) and to debit such beneficial interests to
the respective accounts as specified in the written instructions and (2) shall
thereupon promptly authenticate and deliver at the Corporate Trust Office (as
the office of the Security Registrar), or send by mail (at the risk of the
transferee) to such address as the transferee may request, the Restrictive
Definitive Note or Notes, registered in the requested name as specified in the
written instructions.

         (d) Exchange of Restricted Definitive Notes for other Restricted
Definitive Notes.

         A Restricted Definitive Note may be exchanged or transferred in whole
or in part in the principal amount of authorized denominations of such
Restricted Definitive Note, upon receipt by the Trustee (as Security Registrar)
at its Corporate Trust Office of: (i) in the case of an exchange, a written
request for exchange, (ii) a Transfer Certificate in the appropriate form, and
(iii) a new Restricted Definitive Note issued and duly executed by the Issuer.
In exchange for any Restricted Definitive Note properly presented for exchange
or transfer, the Trustee shall promptly authenticate and deliver at the
Corporate Trust Office (as the office of the Security Registrar), or send by
mail (at the risk of the holder (in the case of exchanges only) or transferee)
to such address as the holder (in the case of exchanges only) or transferee may
request another Restricted Definitive Note or Notes, registered in the name of
such holder or transferee, for the same aggregate principal amount that was
exchanged or transferred.

                                 Article Three
                      Amendments to the Original Indenture

Section 3.1. Amendments to the Original Indenture.

         The Issuer covenants and agrees for the benefit of the Holders of the
Notes only that, for so long as any Note is Outstanding under this Second
Supplemental Indenture, it shall observe the following modifications to certain
definitions and affirmative covenants contained in the Original Indenture, but
only with respect to the Notes:

         (a) Definitions.

         For the avoidance of doubt, the phrase "... and any future expansions
or extensions of these facilities" in the definition of "Pipeline" in Section
1.1 of the Original Indenture shall include the Eastchester Extension and the
Athens Expansion.



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<PAGE>

         (b) Financial Statements and Other Information.

         The reference to "90 days," in Section 6.1(d)(i) and 6.1(f) of the
Original Indenture, and to "45 days" in Section 6.1(d)(ii) of the Original
Indenture shall be references to such shorter period or fewer number of days as
is mandated by law or by the SEC by rulemaking or regulation, or otherwise as
the time period by which Exchange Act reporting issuers are required to file
their annual report and quarterly reports, respectively, pursuant to Section
13(a) or 15(d) of the Exchange Act. The Issuer shall promptly notify the Trustee
of any change in its reporting requirements resulting from the operation of this
clause (b). The Issuer shall provide copies of the reports and other information
required to be delivered to the Trustee pursuant to Section 6.1(d) and 6.1(f) of
the Original Indenture to any beneficial holder of Notes that so requests of the
Issuer.

         (c) Maintenance of Insurance.

         Section 6.1(i) of the Original Indenture is hereby deleted in its
entirety and is hereby replaced with the following:

               (i) Maintenance of Insurance. The Issuer shall provide or cause
          to be provided, for itself and its Subsidiaries, insurance (including
          appropriate self-insurance) against loss or damage of the kinds
          customarily insured against by companies similarly situated in the
          industry in which the Issuer or the Subsidiaries are then conducting
          business and owning like properties, including, but not limited to,
          products liability insurance and public liability insurance, with
          reputable insurers or with the government of the United States of
          America, or an agency or instrumentality thereof, in such amounts,
          with such deductibles and by such methods as shall be customary for
          companies similarly situated in the industry in which the Issuer or
          the Subsidiaries are then conducting business and owning like
          properties.

         (d) SEC Reports and Reports to Holders.

         Section 6.1(j) of the Original Indenture is hereby deleted in its
entirety and is hereby replaced with the following:

               (j) SEC Reports and Reports to Holders. The Issuer shall continue
          to file with the SEC all such reports and other information that the
          Issuer is required to file with the SEC by Section 13(a) or 15(d)
          under the Exchange Act as a United States issuer. For so long as the
          Issuer is required to file such reports and/or other information with
          the SEC, the Issuer shall supply to the Trustee and each Holder of the
          Notes (including each beneficial holder of the Notes so requesting) or
          shall supply to the Trustee for forwarding to each such Holder or
          beneficial holder together with written directions to forward such
          reports and/or other information to such Holder or beneficial holder,
          without cost to such Holder (including any such beneficial holder),
          copies of such reports and/or other



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<PAGE>

          information. If at any time the Issuer is not required to file such
          reports and/or other information with the SEC and for so long as any
          Note remains Outstanding, the Issuer shall nonetheless continue to
          supply to the Trustee and each Holder of such Notes (including each
          beneficial holder of the Notes so requesting) or shall supply to the
          Trustee for forwarding to each such Holder or beneficial holder
          together with written directions to forward such reports and/or other
          information to such Holder or beneficial holder, without cost to such
          Holder (including any such beneficial holder), reports and/or other
          information that are substantially similar to the reports and/or other
          information that the Issuer otherwise would have been required to file
          with the SEC under Section 13(a) or 15(d) of the Exchange Act as a
          United States issuer within the time specified by the Exchange Act.

                                  Article Four
                                   Depositary

Section 4.1. Depositary.

         DTC or its nominee will be the Depositary.

         The Global Notes may not be transferred except by the Depositary to a
nominee of the Depositary or by a nominee of the Depositary to the Depositary or
another nominee of the Depositary or to a successor Depositary or a nominee of a
successor Depositary.

                                  Article Five
                                 Miscellaneous

Section 5.1. Execution of Supplemental Indenture.

         This Second Supplemental Indenture is executed and shall be construed
as an indenture supplemental to the Original Indenture and, as provided in the
Original Indenture, this Second Supplemental Indenture forms a part thereof. The
Notes executed, authenticated and delivered under this Second Supplemental
Indenture constitute a series and shall not be considered to be a part of the
series executed, authenticated and delivered under the First Supplemental
Indenture or any other supplemental indenture entered into pursuant to the
Original Indenture.

Section 5.2. Conflict with Trust Indenture Act.

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

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<PAGE>

Section 5.3. Effect of Headings.

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

Section 5.4. Successors and Assigns.

         All covenants and agreements in this Second Supplemental Indenture by
the Issuer shall bind its successors and assigns, whether so expressed or not.

Section 5.5. Severability Clause.

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

Section 5.6. Benefit of Second Supplemental Indenture.

         Nothing in this Second Supplemental Indenture or in the Notes, express
or implied, shall give to any person, other than the parties hereto and their
successors hereunder and the Holders of the Notes, any benefit or any legal or
equitable right, remedy or claim under this Second Supplemental Indenture.

Section 5.7. Execution and Counterparts.

         This Second Supplemental Indenture may be executed in any number of
counterparts, each of which shall be deemed to be an original, but all such
counterparts shall together constitute but one and the same instrument.

Section 5.8. Original Indenture.

         Other than as modified, amended or supplemented pursuant to the terms
of this Second Supplemental Indenture, with respect to the Notes, the Original
Indenture shall remain in full force and effect in accordance with its terms as
it relates to all Outstanding Notes, including the Notes.

Section 5.9. GOVERNING LAW.

         THIS INDENTURE AND THE NOTES SHALL BE GOVERNED BY THE LAWS OF THE STATE
OF NEW YORK.

Section 5.10. Recitals, etc.

         The recitals contained in this Second Supplemental Indenture shall be
taken as the statements of the Issuer, and the Trustee assumes no responsibility
for their correctness and makes no representations as to the validity or
sufficiency of this Second Supplemental Indenture.


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<PAGE>


         IN WITNESS WHEREOF, the parties hereof have caused this Second
Supplemental Indenture to be duly executed by their respective officers,
directors or signatories duly authorized thereto, all as of the day and year
first above written.


                                   IROQUOIS GAS TRANSMISSION
                                      SYSTEM, L.P., as the Issuer

                                   By: Iroquois Pipeline Operating Company,
                                       as Agent of the Issuer


                                   By:   /s/ Craig R. Frew
                                      ------------------------------------------
                                      Name:     Craig R. Frew
                                      Title:    President


                                   By:   /s/ Paul Bailey
                                      ------------------------------------------
                                      Name:     Paul Bailey
                                      Title:    Vice President and Chief
                                                    Financial Officer


                                   JPMORGAN CHASE BANK,
                                   as Trustee, Paying Agent, Security Registrar
                                           and Transfer Agent



                                   By:   /s/ Denise S. Moore
                                      ------------------------------------------
                                       Title:     Assistant Vice President



                         [Second Supplemental Indenture]