THIRD SUPPLEMENTAL AND AMENDING INDENTURE

Exhibit 4.2

DOMINION RESOURCES, INC.

Issuer

TO

THE BANK OF NEW YORK MELLON

(successor to JPMorgan Chase Bank, N.A.)

Original Trustee

AND

DEUTSCHE BANK TRUST COMPANY AMERICAS

Series Trustee

THIRD SUPPLEMENTAL AND AMENDING INDENTURE

DATED AS OF JUNE 1, 2009

2009 SERIES A 8.375% ENHANCED JUNIOR SUBORDINATED NOTES

TABLE OF CONTENTS

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THIRD SUPPLEMENTAL AND AMENDING INDENTURE

THIS THIRD SUPPLEMENTAL AND AMENDING INDENTURE, dated as of June 1, 2009 (this “Third Supplemental and Amending Indenture”), is between DOMINION RESOURCES, INC., a Virginia corporation, having its principal office at 120 Tredegar Street, Richmond, Virginia 23219 (the “Company”), THE BANK OF NEW YORK MELLON (successor to JPMORGAN CHASE BANK, N.A.), a New York banking corporation, as Trustee, having a corporate trust office at 101 Barclay Street, New York, New York 10286 (herein called the “Original Trustee”), and DEUTSCHE BANK TRUST COMPANY AMERICAS, a New York banking corporation, as Trustee of the series of Securities established by this Third Supplemental and Amending Indenture, having a corporate trust office at 60 Wall Street, 27 ^th Floor, New York, New York 10005 (herein called the “Series Trustee”).

W I T N E S S E T H:

WHEREAS , the Company has heretofore entered into a Junior Subordinated Indenture II, dated as of June 1, 2006 (the “Base Indenture”), as heretofore supplemented, with the Original Trustee;

WHEREAS , the Base Indenture is incorporated herein by this reference and the Base Indenture, as heretofore supplemented and as further supplemented and amended by this Third Supplemental and Amending Indenture, is herein called the “Indenture”;

WHEREAS , under the Base Indenture, a new series of Securities may at any time be established in accordance with the provisions of the Base Indenture and the terms of such series may be described by a supplemental indenture executed by the Company and the Trustee;

WHEREAS , the Company proposes to create under the Indenture a new series of Securities;

WHEREAS , the Company is also entering into this Third Supplemental and Amending Indenture with the Original Trustee and the Series Trustee (i) to make certain amendments to the Base Indenture pursuant to Section 10.1(f) of the Base Indenture to permit the appointment of the Series Trustee as Trustee for the series of Securities hereby established, to add to or change any of the provisions of the Base Indenture as shall be necessary to provide for or facilitate the administration of the trusts thereunder by more than one Trustee and to evidence and provide for the acceptance of appointment thereunder by a Trustee with respect to the series of Securities hereby established, and (ii) to make certain amendments to the Base Indenture pursuant to Section 10.1(d) of the Base Indenture relating to the method or methods, if any, by which the payment date or dates of principal for Securities issued on or after the date hereof may be determined and the circumstances, if any, in which such date or dates may be shortened or extended, either automatically or at the election of the Company;

WHEREAS , the Company has requested that the Original Trustee enter into this Third Supplemental and Amending Indenture in connection with (i) the foregoing amendments, and (ii) the Company’s appointing the Series Trustee with all the rights, powers, trusts and duties of the Original Trustee with respect to, and only with respect to, the series of Securities hereby established;

WHEREAS , additional Securities of other series hereafter established, except as may be limited in the Base Indenture as at the time supplemented and modified, may be issued from time to time pursuant to the Indenture as at the time supplemented and modified; and the Original Trustee will, unless and until a Person other than the Original Trustee is appointed to act as Trustee with respect to the Securities of such series, serve as Trustee of such series;

WHEREAS, all requirements necessary to make this Third Supplemental and Amending Indenture a valid instrument in accordance with its terms, and to make the Junior Subordinated Notes (hereinafter defined), when executed by the Company and authenticated and delivered by the Series Trustee, the valid obligations of the Company, have been performed, and the execution and delivery of this Third Supplemental and Amending Indenture has been duly authorized in all respects;

NOW, THEREFORE , in consideration of the agreements and obligations set forth herein and for other good and valuable consideration, the sufficiency of which is hereby acknowledged, the parties hereto hereby agree as follows:

ARTICLE I

DEFINITIONS

1.1 Definition of Terms. For all purposes of this Third Supplemental and Amending Indenture, except as otherwise expressly provided or unless the context otherwise requires:

(a) the terms not otherwise defined herein which are defined in the Base Indenture have the same meanings when used in this Third Supplemental and Amending Indenture;

(b) the terms defined in this Article have the meanings assigned to them in this Article and include the plural as well as the singular;

(c) all other terms used herein which are defined in the Trust Indenture Act of 1939, as amended, whether directly or by reference therein, have the meanings assigned to them therein;

(d) all accounting terms not otherwise defined herein have the meanings assigned to them in accordance with generally accepted accounting principles in the United States of America, and, except as otherwise herein expressly provided, the term “generally accepted accounting principles” with respect to any computation required or permitted hereunder shall mean such accounting principles as are generally accepted in the United States of America at the date of such computation; provided, that when two or more principles are so generally accepted, it shall mean that set of principles consistent with those in use by the Company;

(e) a reference to a Section or Article is to a Section or Article of this Third Supplemental and Amending Indenture unless otherwise stated;

(f) the words “herein,” “hereof” and “hereunder” and other words of similar import refer to this Third Supplemental and Amending Indenture as a whole and not to any particular Article, Section or other subdivision;

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(g) headings are for convenience of reference only and do not affect interpretation;

“Adjusted Treasury Rate” means, with respect to any redemption date: (i) the yield, under the heading which represents the average for the immediately preceding week, appearing in the most recently published statistical release designated “H.15(519)” or any successor publication which is published weekly by the Board of Governors of the Federal Reserve System and which establishes yields on actively traded United States Treasury securities adjusted to constant maturity under the caption “Treasury Constant Maturities,” for the maturity corresponding to the Comparable Treasury Issue (if no maturity is within three months before or after the end of the Designated Period, yields for the two published maturities most closely corresponding to the Comparable Treasury Issue will be determined by an Independent Investment Banker and the Adjusted Treasury Rate will be interpolated or extrapolated from such yields on a straight line basis, rounding to the nearest month); or (ii) if such release (or any successor release) is not published during the week preceding the calculation date or does not contain such yields, the rate per annum equal to the semi-annual equivalent yield to maturity of the Comparable Treasury Issue, calculated using a price for the Comparable Treasury Issue (expressed as a percentage of its principal amount) equal to the Comparable Treasury Price for such redemption date. The Adjusted Treasury Rate shall be calculated on the third Business Day preceding the redemption date.

“Business Day” means a day other than (i) a Saturday or a Sunday, (ii) a day on which banks in New York City are authorized or obligated by law or executive order to remain closed or (iii) a day on which the Corporate Trust Office of the Series Trustee is closed for business.

“Comparable Treasury Issue” means the United States Treasury security selected by an Independent Investment Banker as having a remaining term to maturity comparable to the Designated Period that would be utilized, at the time of selection and in accordance with customary financial practice, in pricing new issues of corporate debt securities of comparable maturity to the Designated Period.

“Comparable Treasury Price” for any redemption date means (i) the average of the Reference Treasury Dealer Quotations for such redemption date, after excluding the highest and lowest Reference Treasury Dealer Quotations, or (ii) if the Independent Investment Banker obtains fewer than five such Reference Treasury Dealer Quotations, the average of all such quotations.

“Corporate Trust Office of the Series Trustee” means the office of the Series Trustee at which at any particular time its corporate trust business with respect to the Junior Subordinated Notes shall be principally administered, which office at the date of original execution of this Third Supplemental and Amending Indenture is located at 60 Wall Street, 27 ^th Floor, New York, New York 10005 (in addition copies of correspondence are to be sent to Deutsche Bank National Trust Company for Deutsche Bank Trust Company Americas, 25 DeForest Avenue, Mail Stop 0105, Summit, New Jersey, 07901).

“Definitive Note Certificates” means Junior Subordinated Notes issued in definitive, fully registered form.

“Designated Period” means the time period from a redemption date for the Junior Subordinated Notes to June 15, 2014.

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“Global Note” has the meaning specified in Section 3.4(a).

“Independent Investment Banker” means any of Banc of America Securities LLC, Citigroup Global Markets Inc., Morgan Stanley & Co. Incorporated, UBS Securities LLC or one other Primary Treasury Dealer selected by Wachovia Capital Markets, LLC and their respective successors, as selected by the Company, or if any such firm is unwilling or unable to serve as such, an independent investment and banking institution of national standing appointed by the Company.

“Interest Payment Dates” means March 15, June 15, September 15 and December 15 of each year, commencing on September 15, 2009.

“Make-Whole Amount” means an amount equal to the greater of:

(a) 100% of the principal amount of the Junior Subordinated Notes then outstanding being redeemed, or

(b) the sum of the present values of (i) the remaining scheduled payments of interest thereon during the Designated Period (not including any portion of such payments of interest accrued as of the redemption date) and (ii) the principal amount of the Junior Subordinated Notes being redeemed assuming, solely for purposes of this calculation, a scheduled payment of such principal on June 15, 2014, discounted to the redemption date on a quarterly basis (assuming a 360-day year consisting of twelve 30-day months) at the Adjusted Treasury Rate, plus 50 basis points, as calculated by an Independent Investment Banker.

“Optional Deferral Period” has the meaning specified in Section 5.1.

“Original Issue Date” means June 17, 2009.

“Primary Treasury Dealer” means a primary United States government securities dealer in the United States.

“Rating Agency Event” means a change in the methodology employed by any nationally recognized statistical rating organization within the meaning of Section 3(a)(62) of the Securities Exchange Act of 1934, as amended (a “rating agency”) that currently publishes a rating for the Company in assigning equity credit to securities such as the Junior Subordinated Notes, as such methodology is in effect on June 10, 2009 (the “current criteria”), which change results in:

(a) the length of time for which such current criteria are scheduled to be in effect being shortened with respect to the Junior Subordinated Notes; or

(b) a lower or higher equity credit being assigned by such rating agency to the Junior Subordinated Notes as of the date of such change than the equity credit that would have been assigned to the Junior Subordinated Notes as of the date of such change by such rating agency pursuant to its current criteria.

“Rating Agency Event Make-Whole Amount” means an amount equal to the greater of:

(a) 100% of the principal amount of the Junior Subordinated Notes then outstanding being redeemed, or

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(b) the sum of the present values of (i) the remaining scheduled payments of interest thereon during the Designated Period (not including any portion of such payments of interest accrued as of the redemption date) and (ii) the principal amount of the Junior Subordinated Notes being redeemed assuming, solely for purposes of this calculation, a scheduled payment of such principal on June 15, 2014, discounted to the redemption date on a quarterly basis (assuming a 360-day year consisting of twelve 30-day months) at the Adjusted Treasury Rate, plus 50 basis points, as calculated by an Independent Investment Banker.

“Record Date” has the meaning specified in Section 3.5(a).

“Reference Treasury Dealer” means Banc of America Securities LLC, Citigroup Global Markets Inc., Morgan Stanley & Co. Incorporated, UBS Securities LLC and one other Primary Treasury Dealer selected by Wachovia Capital Markets, LLC, and their respective successors; provided that, if any such firm or its successors ceases to be a Primary Treasury Dealer, the Company shall substitute another Primary Treasury Dealer.

“Reference Treasury Dealer Quotations” means, with respect to each Reference Treasury Dealer and any redemption date, the average, as determined by the Independent Investment Banker, of the bid and asked prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount) quoted in writing to the Independent Investment Banker at 5:00 p.m., New York City time, on the third business day preceding such redemption date.

“Stated Maturity” has the meaning specified in Section 3.2.

“Tax Event” means the receipt by the Company of an Opinion of Counsel experienced in such tax matters to the effect that, as a result of (a) any amendment to, clarification of, or change (including any announced prospective change) in the laws or treaties of the United States or any political subdivisions or taxing authorities, or any regulations under such laws or treaties, (b) any judicial decision or any official administrative pronouncement, ruling, regulatory procedure, notice or announcement (including any notice or announcement of intent to issue or adopt any such administrative pronouncement, ruling, regulatory procedure or regulation), (c) any amendment to, clarification of, or change in the official position or the interpretation of any such administrative action or judicial decision or any interpretation or pronouncement that provides for a position with respect to such administrative action or judicial decision that differs from the theretofore generally accepted position, in each case by any legislative body, court, governmental authority or regulatory body, irrespective of the time or manner in which such amendment, clarification or change is introduced or made known, or (d) threatened challenge asserted in writing in connection with an audit of the Company or any of its subsidiaries, or a publicly-known threatened challenge asserted in writing against any other taxpayer that has raised capital through the issuance of securities that are substantially similar to the Junior Subordinated Notes, which amendment, clarification, or change is effective, or which administrative action is taken or which judicial decision, interpretation or pronouncement is issued or threatened challenge is asserted or becomes publicly-known, in each case after June 10, 2009, there is more than an insubstantial risk that interest payable by the Company on the Junior Subordinated Notes is not deductible, or within 90 days would not be deductible, in whole or in part, by the Company for United States Federal income tax purposes.

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The terms “Company,” “Original Trustee,” “Series Trustee,” “Base Indenture,” and “Indenture” shall have the respective meanings set forth in the recitals to this Third Supplemental and Amending Indenture and the paragraph preceding such recitals.

ARTICLE II

AMENDMENTS TO THE BASE INDENTURE

2.1 Amendment to Section 1.1. The definition of “Trustee” as set forth in Section 1.1 of the Base Indenture is hereby amended to read as follows:

“The term “Trustee” means the Person named as the “Trustee” in the first paragraph of this instrument until a successor Trustee shall have become such with respect to one or more series of Securities pursuant to the applicable provisions of this Indenture or until a Trustee for a series of Securities shall have become such pursuant to Section 2.1(n) of this Indenture, and thereafter “Trustee” shall mean each Person who is then a Trustee hereunder, provided, however, that if at any time there is more than one such Person, “Trustee” shall mean each such Person and as used with respect to the Securities of any series shall mean the Trustee with respect to the Securities of such series.”

2.2 Amendment to Section 2.1(c). Section 2.1(c) of the Base Indenture is hereby amended and restated as follows:

“(c) the date or dates (if any) on which the principal of the Securities of such series is payable or the method or methods, if any, by which such date or dates shall be determined and the circumstances, if any, under which such date or dates may be shortened or extended, either automatically or at the election of the Company;”

2.3 Amendment to Section 2.1(n). Section 2.1(n) of the Base Indenture is hereby amended and restated as follows:

“(n) if other than the Person named as the ‘Trustee’ in the first paragraph of this instrument (or a successor to such Person pursuant to the applicable provisions of this Indenture) (for purposes of this clause (n), herein called the “Original Trustee”), the identity of a Trustee for the Securities of the series (a “Series Trustee”), and if not the Series Trustee, the identity of the person or persons who shall be registrar for the Securities of such series, and the place or places where the Register of Securities of such series shall be kept, and such additions or changes to any provisions of this Indenture as shall be necessary to provide for or facilitate the administration of the trusts hereunder by more than one Trustee, it being understood, anything contained herein or in any Resolution of the Company, Officers’ Certificate or supplemental indenture to the contrary notwithstanding, that (i) nothing herein shall constitute such Trustees co-trustees of the same trust, (ii) each such Trustee shall be a trustee of a trust or trusts hereunder separate and apart from any trust or trusts hereunder administered by any other such Trustee, (iii) the Series Trustee shall have all the rights, powers, trusts and duties of the Original Trustee with respect to, and only with respect to, the Securities of the series, (iv) the Original Trustee shall have no rights, powers, trusts and duties with respect to the Securities of the series, (v) no Trustee hereunder shall have any liability for any acts or omissions of any other Trustee hereunder and (vi) no appointment of a Series Trustee shall become effective until the acceptance of the appointment by the Series Trustee is evidenced in writing;”

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2.4 Amendment to Section 2.12. Section 2.12 of the Base Indenture is hereby amended and restated as follows:

“ Section 2.12 Shortening or Extension of Stated Maturity. If specified as contemplated by Section 2.1 or Section 2.2 with respect to the Securities of a particular series, the Company shall have the right to (i) shorten the Stated Maturity of the principal of the Securities of such series at any time to any date, and (ii) extend the Stated Maturity of the principal of the Securities of such series at any time at its election for one or more periods, provided that, if the Company elects to exercise its right to shorten or extend the Stated Maturity of the principal of the Securities of such series pursuant to this section, at the time such election is made and at the time of such shortening or extension, such conditions as may be specified in such Securities shall have been satisfied.”

ARTICLE III

GENERAL TERMS AND CONDITIONS OF THE JUNIOR SUBORDINATED NOTES

3.1 Designation and Principal Amount. There is hereby established a new series of Securities to be issued under the Indenture, to be designated as the Company’s 2009 Series A 8.375% Enhanced Junior Subordinated Notes (the “Junior Subordinated Notes”) in an aggregate principal amount of up to $687,500,000 which amount shall be set forth in any written orders of the Company for the authentication and delivery of Junior Subordinated Notes pursuant to Section 2.1 of the Base Indenture and Section 7.1 hereof. Additional Junior Subordinated Notes without limitation as to amount, and without the consent of the holders of the then Outstanding Junior Subordinated Notes, may also be authenticated and delivered in the manner provided in Section 2.1 of the Base Indenture. Any such additional Junior Subordinated Notes will have the same Stated Maturity and other terms (except, if applicable, the initial Interest Payment Date and initial interest accrual date) as those initially issued and shall be consolidated with and part of the same series of Junior Subordinated Notes as the Junior Subordinated Notes initially issued under this Third Supplemental and Amending Indenture.

3.2 Maturity. The maturity date of the Junior Subordinated Notes initially will be June 15, 2064, but will be automatically extended, except for any portion of the principal amount of the Junior Subordinated Notes that shall have been earlier redeemed or with respect to which notice of redemption shall have been given to the holders of such Junior Subordinated Notes, for additional quarterly periods on each of March 15, June 15, September 15 and December 15, beginning on June 15, 2014 through and including March 15, 2019, without notice to, or consent of, the holders of the Junior Subordinated Notes. Subject to the conditions described below, the maturity date will be further automatically extended for additional quarterly periods beginning on June 15, 2019 through and including March 15, 2029, except for any portion of the principal amount of the Junior Subordinated Notes that shall have been earlier redeemed or with respect to which notice of redemption shall have been given to the holders of such Junior Subordinated Notes. The final maturity date of the Junior Subordinated Notes will be no later than June 15, 2079, on which date the entire principal amount of the Junior Subordinated Notes will become due and payable, together with any accrued and unpaid interest. The Stated Maturity of the Junior Subordinated Notes shall mean the maturity date of the Junior Subordinated Notes as extended in accordance with this Section 3.2, which may not be otherwise shortened or extended.

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With respect to each extension beginning on June 15, 2019, the following shall constitute the extension conditions:

(a) On the applicable extension date the ratings on the Junior Subordinated Notes satisfy at least two of the three following ratings criteria: (i) at least Baa3 by Moody’s Investors Service (“Moody’s”), (ii) at least BBB- by Standard & Poors Ratings Services (“Standard & Poor’s”) and (iii) at least BBB- by Fitch Ratings Ltd (“Fitch”), or, if Moody’s, Standard & Poor’s and/or Fitch (or their respective successors) are no longer in existence, the equivalent rating by a nationally recognized statistical rating organization; and

(b) During the three years prior to the applicable extension date:

(i) no event of default has occurred in respect of any of the Company’s then outstanding indebtedness for money borrowed; and

(ii) the Company did not have (and does not have at the extension date) any outstanding deferred payments under any of its then-outstanding preferred stock or debt securities.

3.3 Form and Payment; Minimum Transfer Restriction.

(a) The Junior Subordinated Notes shall be issued in fully registered definitive form without coupons in minimum denominations of $25 and integral multiples of $25 in excess thereof. Principal and interest on the Junior Subordinated Notes will be payable, the transfer of such Junior Subordinated Notes will be registrable and such Junior Subordinated Notes will be exchangeable for Junior Subordinated Notes bearing identical terms and provisions at the Corporate Trust Office of the Series Trustee; provided, however, that payment of interest may be made at the option of the Company by check mailed to the Person entitled thereto at such address as shall appear in the Register or by transfer to an account maintained by the Person entitled thereto as specified in the Register, provided that proper transfer instructions have been received by the Paying Agent by the Record Date. The Register for the Junior Subordinated Notes shall be kept at the Corporate Trust Office of the Series Trustee, and the Series Trustee is hereby appointed registrar and Paying Agent for the Junior Subordinated Notes.

(b) The Junior Subordinated Notes may be transferred or exchanged only in minimum denominations of $25 and integral multiples of $25 in excess thereof, and any attempted transfer, sale or other disposition of Junior Subordinated Notes in a denomination of less than $25 shall be deemed to be void and of no legal effect whatsoever. Any such transferee shall be deemed not to be the holder of such Junior Subordinated Notes for any purpose, including but not limited to the receipt of payments in respect of such Junior Subordinated Notes and such transferee shall be deemed to have no interest whatsoever in such Junior Subordinated Notes.

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3.4 Exchange and Registration of Transfer of Junior Subordinated Notes; Restrictions on Transfers; Depositary. The Junior Subordinated Notes will be issued to the holders in accordance with the following procedures:

(a) So long as Junior Subordinated Notes are eligible for book-entry settlement with the Depositary, or unless required by law, all Junior Subordinated Notes that are so eligible will be represented by one or more Junior Subordinated Notes in global form (a “Global Note”) registered in the name of the Depositary or the nominee of the Depositary. Except as provided in Section 3.4(c) below, beneficial owners of a Global Note shall not be entitled to have Definitive Note Certificates registered in their names, will not receive or be entitled to receive physical delivery of Definitive Note Certificates and will not be registered holders of such Global Notes.

(b) The transfer and exchange of beneficial interests in Global Notes shall be effected through the Depositary in accordance with the Indenture and the procedures and standing instructions of the Depositary and the Series Trustee shall make appropriate endorsements to reflect increases or decreases in principal amounts of such Global Notes.

(c) Notwithstanding any other provisions of the Indenture (other than the provisions set forth in this Section 3.4(c)), a Global Note may not be exchanged in whole or in part for Junior Subordinated Notes registered, and no transfer of a Global Note may be registered, in the name of any person other than the Depositary or a nominee thereof unless (i) such Depositary (A) has notified the Company that it is unwilling or unable to continue as Depositary for such Global Note or (B) has ceased to be a clearing agency registered as such under the Exchange Act and no successor Depositary has been appointed by the Company within 90 days after its receipt of such notice or its becoming aware of such ineligibility, (ii) there shall have occurred and be continuing an Event of Default, or any event which after notice or lapse of time or both would be an Event of Default under the Indenture, with respect to such Junior Subordinated Note, or (iii) the Company, in its sole discretion and subject to the procedures of the Depositary, instructs the Series Trustee to exchange such Global Note for a Junior Subordinated Note that is not a Global Note (in which case such exchange (subject to such procedures) shall be effected by the Series Trustee).

The Depositary shall be a clearing agency registered under the Exchange Act. The Company initially appoints The Depository Trust Company to act as Depositary with respect to the Global Notes. Initially, the Global Notes shall be registered in the name of Cede & Co., as the nominee of the Depositary, and deposited with the Series Trustee as custodian for Cede & Co.

Definitive Note Certificates issued in exchange for all or a part of a Global Note pursuant to this Section 3.4(c) shall be registered in such names and in such authorized denominations as the Depositary, pursuant to instructions from its direct or indirect participants or otherwise, shall instruct the Series Trustee. Upon execution and authentication, the Series Trustee shall deliver such Definitive Note Certificates to the person in whose names such Definitive Note Certificates are so registered.

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So long as Junior Subordinated Notes are represented by one or more Global Notes, (i) the registrar for the Junior Subordinated Notes and the Series Trustee shall be entitled to deal with the clearing agency for all purposes of the Indenture relating to such Global Notes as the sole holder of the Junior Subordinated Notes evidenced by such Global Notes and shall have no obligations to the holders of beneficial interests in such Global Notes; and (ii) the rights o