<PAGE>

                                                                   Exhibit  4.3



                        CONSOLIDATED NATURAL GAS COMPANY
                                     Issuer

                  BANK ONE TRUST COMPANY, NATIONAL ASSOCIATION
                                     Trustee

                            -------------------------

                          Third Supplemental Indenture

                          Dated as of October 25, 2001

                            -------------------------

                                  $450,000,000

                        2001 Series C 6.250% Senior Notes


                              Due November 1, 2011
<PAGE>

                              TABLE OF CONTENTS/1/


ARTICLE I 2001 SERIES C 6.250% SENIOR NOTES.................................  1

     SECTION 101.    Establishment..........................................  1
     SECTION 102.    Definitions............................................  2
     SECTION 103.    Payment of Principal and Interest......................  4
     SECTION 104.    Denominations..........................................  5
     SECTION 105.    Global Securities......................................  5
     SECTION 106.    Mandatory Redemption...................................  6
     SECTION 107.    Optional Redemption....................................  6
     SECTION 108.    Sinking Fund...........................................  6
     SECTION 109.    Additional Interest....................................  7
     SECTION 110.    Paying Agent...........................................  7

ARTICLE II MISCELLANEOUS PROVISIONS.........................................  7

     SECTION 201.    Recitals by Company....................................  7
     SECTION 202.    Ratification and Incorporation of Original Indenture...  7
     SECTION 203.    Executed in Counterparts...............................  7
     SECTION 204.    Assignment.............................................  7


------------------
/1/   This Table of Contents does not constitute part of the Indenture or have
      any bearing upon the interpretation of any of its terms and provisions.
<PAGE>

     THIS THIRD SUPPLEMENTAL INDENTURE is made as of the 25th day of October,
2001, by and between CONSOLIDATED NATURAL GAS COMPANY, a Delaware corporation,
having its principal office at 120 Tredegar Street, Richmond, Virginia 23219
(the "Company"), and BANK ONE TRUST COMPANY, NATIONAL ASSOCIATION, as Trustee
(herein called the "Trustee").

                              W I T N E S S E T H:

     WHEREAS, the Company has heretofore entered into an Indenture, dated as of
April 1, 2001 (the "Original Indenture"), with the Trustee;

     WHEREAS, the Original Indenture is incorporated herein by this reference
and the Original Indenture, as supplemented by this Third Supplemental
Indenture, is herein called the "Indenture";

     WHEREAS, under the Original Indenture, a new series of Securities may at
any time be established in accordance with the provisions of the Original
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 series of
Securities;

     WHEREAS, additional Securities of other series hereafter established,
except as may be limited in the Original 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

     WHEREAS, all conditions necessary to authorize the execution and delivery
of this Third Supplemental Indenture and to make it a valid and binding
obligation of the Company have been done or performed.

     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
                        2001 SERIES C 6.250% SENIOR NOTES

     SECTION 101. Establishment. There is hereby established a new series of
Securities to be issued under the Indenture, to be designated as the Company's
2001 Series C 6.250% Senior Notes Due November 1, 2011 (the "Series C Senior
Notes").

     There are to be initially authenticated and delivered $450,000,000
principal amount of Series C Senior Notes, and such principal amount of the
Series C Senior Notes may be increased from time to time pursuant to Section 301
of the Original Indenture.  All Series C Senior Notes need not be issued at the
same time, and such series may be reopened at any time, without the consent of
any Holder, for issuances of additional Series C Senior Notes.  Any such
additional Series C Senior Notes will have the same interest rate, maturity and
<PAGE>

other terms as those initially issued.  Further Series C Senior Notes may be
also authenticated and delivered as provided by Sections 304, 305, 306, 905 or
1107 of the Original Indenture.

     The Series C Senior Notes shall be issued in definitive fully registered
form without coupons, in substantially the form set out in Exhibit A hereto. The
entire initially issued principal amount of the Series C Senior Notes shall
initially be evidenced by one or more certificates issued to Cede & Co., as
nominee for The Depository Trust Company.

     The form of the Trustee's Certificate of Authentication for the Series C
Senior Notes shall be in substantially the form set forth in Exhibit B hereto.

     Each Series C Senior Note shall be dated the date of authentication thereof
and shall bear interest from the date of original issuance thereof or from the
most recent Interest Payment Date to which interest has been paid or duly
provided for.

     SECTION 102. Definitions. The following defined terms used herein shall,
unless the context otherwise requires, have the meanings specified below.
Capitalized terms used herein for which no definition is provided herein shall
have the meanings set forth in the Original Indenture.

     "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 Remaining Life, yields for the two published
maturities most closely corresponding to the Comparable Treasury Issue shall be
determined and the adjusted Treasury Rate shall 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.

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

     "Comparable Treasury Issue" means the United States Treasury security
selected by an Independent Investment Banker as having a maturity comparable to
the remaining term of the Series C Senior Notes to be redeemed 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 remaining term of such Series C Senior Notes.

                                       2
<PAGE>

     "Comparable Treasury Price" means (i) the average of five 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.

     "Independent Investment Banker" means any of Banc of America Securities
LLC, Goldman, Sachs & Co. and Merrill Lynch, Pierce, Fenner & Smith Incorporated
and their respective successors, as selected by us, or if all of those firms are
unwilling or unable to serve as such, an independent investment and banking
institution of national standing appointed by the Company.

     "Interest Payment Dates" means November 1 and May 1 of each year,
commencing on May 1, 2002.

     "Mandatory Redemption" means the redemption of the Series C Senior Notes,
in whole but not in part at the applicable Mandatory Redemption Price on the
applicable Mandatory Redemption Date.

     "Mandatory Redemption Price" means 100.25% of the aggregate principal
amount of the Series C Senior Notes, together with accrued and unpaid interest
and thereon from and including October 25, 2001, to but excluding the Mandatory
Redemption Date, and shall also be a "Redemption Price" for purposes of the
Original Indenture and this Third Supplemental Indenture.

     "Mandatory Redemption Date" means the earlier to occur of (i) January 21,
2002 if the Merger has not been completed on or prior to December 31, 2001 or
(ii) the 20th day (or if such day is not a Business Day, the first Business Day
thereafter) following the date on which the Merger Agreement is terminated, in
either case, on or prior to December 31, 2001, and shall also be a "Redemption
Date" for purposes of the Original Indenture and this Third Supplemental
Indenture.

     "Merger" means the proposed acquisition by Dominion Resources, Inc. of
Louis Dreyfus Natural Gas Corp., pursuant to the Merger Agreement.

     "Merger Agreement" means the Agreement and Plan of Merger, dated as of
September 9, 2001, as amended, among Dominion Resources, Inc., Consolidated
Natural Gas Company and Louis Dreyfus Natural Gas Corp.

     "Original Issue Date" means October 25, 2001.

     "Reference Treasury Dealer" means:  (i) each of Banc of America Securities
LLC, Goldman, Sachs & Co. and Merrill Lynch, Pierce, Fenner & Smith Incorporated
and their successors; provided that, if any of the foregoing ceases to be a
primary U.S. Government securities dealer in New York City (a "Primary Treasury
Dealer"), the Company shall substitute another Primary Treasury Dealer; and (ii)
up to two other Primary Treasury Dealers selected by the Company.

                                       3
<PAGE>

     "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.

     "Regular Record Date" means, with respect to each Interest Payment Date,
the close of business on the Business Day preceding such Interest Payment Date;
provided, that with respect to Series C Senior Notes that are not represented by
one or more Global Securities, the Regular Record Date shall be the close of
business on the 15th calendar day (whether or not a Business Day) preceding such
Interest Payment Date.

     "Remaining Life" means the remaining term of the Series C Senior Notes.

     "Stated Maturity" means November 1, 2011.

     SECTION 103. Payment of Principal and Interest. The principal of the Series
C Senior Notes shall be due at the Stated Maturity (unless earlier redeemed).
The unpaid principal amount of the Series C Senior Notes shall bear interest at
the rate of 6.250% per annum until paid or duly provided for, such interest to
accrue from the Original Issue Date or from the most recent Interest Payment
Date to which interest has been paid or duly provided for. Interest shall be
paid semi-annually in arrears on each Interest Payment Date to the Person in
whose name the Series C Senior Notes are registered on the Regular Record Date
for such Interest Payment Date; provided that interest payable at the Stated
Maturity of principal or on a Redemption Date as provided herein will be paid to
the Person to whom principal is payable. Any such interest that is not so
punctually paid or duly provided for will forthwith cease to be payable to the
Holders on such Regular Record Date and may either be paid to the Person or
Persons in whose name the Series C Senior Notes are registered at the close of
business on a Special Record Date for the payment of such defaulted interest to
be fixed by the Trustee (in accordance with Section 307 of the Original
Indenture), notice whereof shall be given to Holders of the Series C Senior
Notes not less than ten (10) days prior to such Special Record Date, or be paid
at any time in any other lawful manner not inconsistent with the requirements of
any securities exchange, if any, on which the Series C Senior Notes may be
listed, and upon such notice as may be required by any such exchange, all as
more fully provided in the Original Indenture.

     Payments of interest on the Series C Senior Notes will include interest
accrued to but excluding the respective Interest Payment Dates. Interest
payments for the Series C Senior Notes shall be computed and paid on the basis
of a 360-day year of twelve 30-day months. If any date on which interest is
payable on the Series C Senior Notes is not a Business Day, then payment of the
interest payable on such date will be made on the next succeeding day that is a
Business Day (and without any interest or payment in respect of any such delay),
in each case with the same force and effect as if made on the date the payment
was originally payable.

     Payment of the principal and interest on the Series C Senior Notes shall be
made at the office of the Paying Agent in such currency of the United States of
America as at the time of payment is legal tender for payment of public and

                                       4
<PAGE>

private debts, with any such payment that is due at the Stated Maturity of any
Series C Senior Notes or on a Redemption Date being made upon surrender of such
Series C Senior Notes to the Paying Agent. Payments of interest (including
interest on any Interest Payment Date) will be made, subject to such surrender
where applicable, at the option of the Company, (i) by check mailed to the
address of the Person entitled thereto as such address shall appear in the
Security Register or (ii) by wire transfer at such place and to such account at
a banking institution in the United States as may be designated in writing to
the Trustee at least sixteen (16) days prior to the date for payment by the
Person entitled thereto.  If any date on which principal and interest is payable
on the Series C Senior Notes is not a Business Day, then payment of the
principal and interest payable on such date will be made on the next succeeding
day that is a Business Day (and without any interest or payment in respect of
any such delay), in each case with the same force and effect as if made on the
date the payment was originally payable.

     SECTION 104. Denominations. The Series C Senior Notes may be issued in
denominations of $1,000, or any integral multiple thereof.

     SECTION 105. Global Securities. The Series C Senior Notes will be issued
initially in the form of one or more Global Securities registered in the name of
the Depositary (which shall be The Depository Trust Company) or its nominee.
Except under the limited circumstances described below, Series C Senior Notes
represented by such Global Securities will not be exchangeable for, and will not
otherwise be issuable as, Series C Senior Notes in definitive form. The Global
Securities described above 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 its nominee.

     Owners of beneficial interests in such a Global Security will not be
considered the Holders thereof for any purpose under the Indenture, and no
Global Security representing a Series C Senior Note shall be exchangeable,
except for another Global Security of like denomination and tenor to be
registered in the name of the Depositary or its nominee or to a successor
Depositary or its nominee or except as described below. The rights of Holders of
such Global Security shall be exercised only through the Depositary.

     A Global Security shall be exchangeable for Series C Senior Notes
registered in the names of persons other than the Depositary or its nominee only
if (i) the Depositary notifies the Company that it is unwilling or unable to
continue as a Depositary for such Global Security and no successor Depositary
shall have been appointed by the Company within 90 days of receipt by the
Company of such notification, or if at any time the Depositary ceases to be a
clearing agency registered under the Exchange Act at a time when the Depositary
is required to be so registered to act as such Depositary and no successor
Depositary shall have been appointed by the Company within 90 days after it
becomes aware of such cessation, or (ii) the Company in its sole discretion
determines that such Global Security shall be so exchangeable.  Any Global
Security that is exchangeable pursuant to the preceding sentence shall be
exchangeable for Series C Senior Notes registered in such names as the
Depositary shall direct.

                                       5
<PAGE>

     SECTION 106. Mandatory Redemption. In the event that (i) for any reason the
Merger has not been completed on or prior to December 31, 2001 on substantially
the terms in effect on October 22, 2001 or (ii) or the Merger Agreement is
terminated on or prior to December 31, 2001, the Company shall redeem this Note,
in whole but not in part, at the applicable Mandatory Redemption Price on the
applicable Mandatory Redemption Date.

     The Company shall notify the Trustee and concurrently mail, or cause to be
mailed, notice of any Mandatory Redemption promptly after the occurrence of the
event triggering such redemption to the Holder and thereof at its registered
address.  Such notice shall not be subject to the provisions of Section 1104 of
the Original Indenture that otherwise require notice to be given not less than
20 nor more than 60 days prior to the Redemption Date.

     SECTION 107. Optional Redemption. The Series C Senior Notes are redeemable,
in whole or in part, at any time after the last date on which a Mandatory
Redemption may occur, and at the option of the Company, at a Redemption Price
equal to the greater of:

     (i)  100% of the principal amount of Series C Senior Notes then Outstanding
to be so redeemed, or

     (ii) the sum of the present values of the remaining scheduled payments of
principal and interest thereon (not including any portion of such payments of
interest accrued as of the Redemption Date) discounted to the Redemption Date on
a semiannual basis (assuming a 360-day year consisting of twelve 30-day months)
at the Adjusted Treasury Rate, plus 25 basis points, as calculated by an
Independent Investment Banker,

     plus, in either of the above cases, accrued and unpaid interest thereon to
the Redemption Date.

     Unless the Company defaults in the payment of the Redemption Price, on and
after the Redemption Date, interest will cease to accrue on the Series C Senior
Notes or portions thereof called for redemption.

     The Adjusted Treasury Rate shall be calculated on the third Business Day
preceding the Redemption Date.

     In the event of the redemption of the Series C Senior Notes in part only, a
new Series C Senior Note or Notes for the unredeemed portion will be issued in
the name or names of the Holders thereof upon surrender thereof.

     Notice of redemption shall be given as provided in Section 1104 of the
Original Indenture.

     SECTION 108. Sinking Fund. The Series C Senior Notes shall not have a
sinking fund.

                                       6
<PAGE>

     SECTION 109. Additional Interest. Any principal of and installment of
interest on the Series C Senior Notes that is overdue shall bear interest at the
rate of 6.250% (to the extent that the payment of such interest shall be legally
enforceable), from the dates such amounts are due until they are paid or made
available for payment, and such interest shall be payable on demand.

     SECTION 110. Paying Agent. The Trustee shall initially serve as Paying
Agent with respect to the Series C Senior Notes, with the Place of Payment
initially being the Corporate Trust Office of the Trustee.

                                   ARTICLE II
                            MISCELLANEOUS PROVISIONS

     SECTION 201. Recitals by Company. The recitals in this Third Supplemental
Indenture are made by the Company only and not by the Trustee, and all of the
provisions contained in the Original Indenture in respect of the rights,
privileges, immunities, powers and duties of the Trustee shall be applicable in
respect of the Series C Senior Notes and of this Third Supplemental Indenture as
fully and with like effect as if set forth herein in full.

     SECTION 202. Ratification and Incorporation of Original Indenture. As
supplemented hereby, the Original Indenture is in all respects ratified and
confirmed, and the Original Indenture and this Third Supplemental Indenture
shall be read, taken and construed as one and the same instrument.

     SECTION 203. Executed in Counterparts. This Third Supplemental Indenture
may be executed in several counterparts, each of which shall be deemed to be an
original, and such counterparts shall together constitute but one and the same
instrument.

     SECTION 204. Assignment. The Company shall have the right at all times to
assign any of its rights or obligations under the Indenture with respect to the
Series C Senior Notes to a direct or indirect wholly-owned subsidiary of the
Company; provided that, in the event of any such assignment, the Company shall
remain fully liable for the performance of all such obligations. The Indenture
may also be assigned by the Company in connection with a transaction described
in Article Eight of the Original Indenture.


                                       7
<PAGE>

     IN WITNESS WHEREOF, each party hereto has caused this instrument to be
signed in its name and behalf by its duly authorized officer, all as of the day
and year first above written.

                              CONSOLIDATED NATURAL GAS COMPANY



                              By:_______________________________________

                              Name:____________________________________

                              Title:_____________________________________


                              BANK ONE TRUST COMPANY, NATIONAL
                              ASSOCIATION, as Trustee



                              By:_______________________________________

                              Name:____________________________________

                              Title:_____________________________________


                                       8
<PAGE>

                                    EXHIBIT A

                                     FORM OF
                        2001 SERIES C 6.250% SENIOR NOTE
                              DUE NOVEMBER 1, 2011

     [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF
THE DEPOSITORY TRUST COMPANY (55 WATER STREET, NEW YORK, NEW YORK) TO THE ISSUER
OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY
CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR SUCH OTHER NAME AS
REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND
ANY PAYMENT IS MADE TO CEDE & CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR
VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER
HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.]**

     [THIS SERIES C SENIOR NOTE IS A GLOBAL SECURITY WITHIN THE MEANING OF THE
INDENTURE HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITARY
OR A NOMINEE THEREOF.  THIS SERIES C SENIOR NOTE MAY NOT BE EXCHANGED IN WHOLE
OR IN PART FOR A SECURITY REGISTERED, AND NO TRANSFER OF THIS SERIES C SENIOR
NOTE IN WHOLE OR IN PART MAY BE REGISTERED, IN THE NAME OF ANY PERSON OTHER THAN
SUCH  DEPOSITARY OR A NOMINEE THEREOF, EXCEPT IN THE LIMITED CIRCUMSTANCES
DESCRIBED IN THE INDENTURE.]**


                        -------------------------------

                              CONSOLIDATED NATURAL
                                  GAS COMPANY

                        -------------------------------

                                  $450,000,000
                        2001 SERIES C 6.250% SENIOR NOTE
                              DUE NOVEMBER 1, 2011

No. C-1                                                 CUSIP No. 209615 BX 0


     Consolidated Natural Gas Company, a corporation duly organized and existing
under the laws of Delaware (herein called the "Company", which term includes any
successor Person under the Indenture hereinafter referred to), for value


----------------
** Insert in Global Securities.
<PAGE>

received, hereby promises to pay to [Cede & Co.] **, or registered assigns (the
"Holder"), the principal sum of Four Hundred Fifty Million Dollars
($450,000,000) on November 1, 2011 and to pay interest thereon from October 25,
2001 or from the most recent Interest Payment Date to which interest has been
paid or duly provided for, semi-annually in arrears on November 1 and May 1 of
each year, commencing on May 1, 2002, at the rate of 6.250% per annum, until the
principal hereof is paid or made available for payment, provided that any
principal, and any such installment of interest, that is overdue shall bear
interest at the rate of 6.250% per annum (to the extent that the payment of such
interest shall be legally enforceable), from the dates such amounts are due
until they are paid or made available for payment, and such interest shall be
payable on demand.  The interest so payable, and punctually paid or duly
provided for, on any Interest Payment Date will, as provided in such Indenture,
be paid to the Person in whose name this Series C Senior Note (or one or more
Predecessor Securities) is registered at the close of business on the Regular
Record Date for such interest, which shall be the close of business on the
Business Day preceding such Interest Payment Date, provided, that with respect
to Series C Senior Notes that are not represented by one or more Global
Securities, the Regular Record Date  shall be the close of business on the 15th
calendar day (whether or not a Business Day) next preceding such Interest
Payment Date; and  provided further, that interest payable at the Stated
Maturity of principal or on a Redemption Date will be paid to the Person to whom
principal is payable.  Any such interest not so punctually paid or duly provided
for will forthwith cease to be payable to the Holder on such Regular Record Date
and may either be paid to the Person in whose name this Series C Senior Note (or
one or more Predecessor Securities) is registered at the close of business on a
Special Record Date for the payment of such Defaulted Interest to be fixed by
the Trustee, notice whereof shall be given to Holders of Series C Senior Notes
not less than 10 days prior to such Special Record Date, or be paid at any time
in any other lawful manner not inconsistent with the requirements of any
securities exchange on which the Series C Senior Notes may be listed, and upon
such notice as may be required by such exchange, all as more fully provided in
said Indenture.

     Payment of the principal of and any such interest on this Series C Senior
Note will be made at the office of the Paying Agent, in the Borough of
Manhattan, City and State of New York, in such coin or currency of the United
States of America as at the time of payment is legal tender for payment of
public and private debts, with any such payment that is due at the Stated
Maturity of any Series C Senior Note or on a Redemption Date being made upon
surrender of such Series C Senior Note to such office or agency; provided,
however, that at the option of the Company payment of interest, subject to such
surrender where applicable, may be made (i) by check mailed to the address of
the Person entitled thereto as such address shall appear in the Security
Register or (ii) by wire transfer at such place and to such account at a banking
institution in the United States as may be designated in writing to the Trustee
at least sixteen (16) days prior to the date for payment by the Person entitled
thereto.

                                       2
<PAGE>

     Reference is hereby made to the further provisions of this Series C Senior
Note set forth on the reverse hereof, which further provisions shall for all
purposes have the same effect as if set forth at this place.

     Unless the certificate of authentication hereon has been executed by the
Trustee referred to on the reverse hereof by manual signature, this Series C
Senior Note shall not be entitled to any benefit under the Indenture or be valid
or obligatory for any purpose.

     IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed.

Dated:                             Consolidated Natural Gas Company


                                   By: ______________________________________

                                       Name: ________________________________

                                       Title: _______________________________


                                        3
<PAGE>

                       [REVERSE OF SERIES C SENIOR NOTE]

     This Security is one of a duly authorized issue of securities of the
Company (herein called the "Securities"), issued and to be issued in one or more
series under an Indenture, dated as of April 1, 2001, as supplemented by a Third
Supplemental Indenture dated as of October 25, 2001 (as amended or supplemented
from time to time, herein called the "Indenture", which term shall have the
meaning assigned to it in such instrument), between the Company and Bank One
Trust Company, National Association, as Trustee (herein called the "Trustee",
which term includes any successor trustee under the Indenture), and reference is
hereby made to the Indenture for a statement of the respective rights,
limitations of rights, duties and immunities thereunder of the Company, the
Trustee and the Holders of the Securities and of the terms upon which the
Securities are, and are to be, authenticated and delivered.  This Security is
one of the series designated on the face hereof (the "Series C Senior Notes")
which is unlimited in aggregate principal amount.

     The Series C Senior Notes must be redeemed by the Company if the proposed
acquisition by Dominion Resources, Inc. of Louis Dreyfus National Gas Corp. has
not been completed on or prior to December 31, 2001 on substantially the terms
in effect on October 22, 2001 or the related merger agreement is terminated on
or prior to December 31, 2001. In either such event, the Company shall redeem
the Series C Senior Notes, in whole but not in part on the applicable mandatory
redemption date in the manner and with the effect provided in the Indenture.

     The Series C Senior Notes are redeemable, in whole or in part, at any time
after the last date on which a Mandatory Redemption may occur, in the manner and
with the effect provided in the Indenture.

     If an Event of Default with respect to Series C Senior Notes shall occur
and be continuing, the principal of the Series C Senior Notes may be declared
due and payable in the manner and with the effect provided in the Indenture.

     The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modification of the rights and obligations of the
Company and the rights of the Holders of the Securities of each series to be
affected under the Indenture at any time by the Company and the Trustee with the
consent of the Holders of a majority in principal amount of the Securities at
the time Outstanding of each series to be affected.  The Indenture also contains
provisions permitting the Holders of specified percentages in principal amount
of the Securities of each Series C the time Outstanding, on behalf of the
Holders of all Securities of such series, to waive certain past defaults under
the Indenture and their consequences.  Any such consent or waiver by the Holder
of this Series C Senior Note shall be conclusive and binding upon such Holder
and upon all future Holders of this Series C Senior Note and of any Series C
Senior Note issued upon the registration of transfer hereof or in exchange
therefor or in lieu hereof, whether or not notation of such consent or waiver is
made upon this Series C Senior Note.

                                       4
<PAGE>

     As provided in and subject to the provisions of the Indenture, the Holder
of this Series C Senior Note shall not have the right to institute any
proceeding with respect to the Indenture or for the appointment of a receiver or
trustee or for any other remedy thereunder, unless such Holder shall have
previously given the Trustee written notice of a continuing Event of Default
with respect to the Series C Senior Notes, the Holders of not less than a
majority in principal amount of the Series C Senior Notes at the time
Outstanding shall have made written request to the Trustee to institute
proceedings in respect of such Event of Default as Trustee and offered the
Trustee reasonable indemnity, and the Trustee shall not have received from the
Holders of a majority in principal amount of Series C Senior Notes at the time
Outstanding a direction inconsistent with such request, and shall have failed to
institute any such proceeding for 60 days after receipt of such notice, request
and offer of indemnity.  The foregoing shall not apply to any suit instituted by
the Holder of this Series C Senior Note for the enforcement of any payment of
principal hereof or premium, if any, or interest hereon on or after the
respective due dates expressed or provided for herein.

     No reference herein to the Indenture and no provision of this Series C
Senior Note or of the Indenture shall alter or impair the obligation of the
Company, which is absolute and unconditional, to pay the principal of, premium,
if any, and interest on this Series C Senior Note at the times, place and rate,
and in the coin or currency, herein prescribed.

     As provided in the Indenture and subject to certain limitations therein set
forth, the transfer of this Series C Senior Note is registrable in the Security
Register, upon surrender of this Series C Senior Note for registration of
transfer at the office or agency of the Company in any place where the principal
of, premium, if any, and interest on this Series C Senior Note are payable, duly
endorsed by, or accompanied by a written instrument of transfer in form
satisfactory to the Company and the Security Registrar duly executed by, the
Holder hereof or his attorney duly authorized in writing, and thereupon one or
more new Series C Senior Notes and of like tenor, of authorized denominations
and for the same aggregate principal amount, will be issued to the designated
transferee or transferees.

     The Series C Senior Notes are issuable only in registered form without
coupons in denominations of $1,000 and any integral multiple thereof.  As
provided in the Indenture and subject to certain limitations therein set forth,
Series C Senior Notes are exchangeable for a like aggregate principal amount of
Series C Senior Notes having the same Stated Maturity and of like tenor of any
authorized denominations as requested by the Holder upon surrender of the Series
C Senior Note or Series C Senior Notes to be exchanged at the office or agency
of the Company.

     No service charge shall be made for any such registration of transfer or
exchange, but the Company may require payment of a sum sufficient to cover any
tax or other governmental charge payable in connection therewith.

     Prior to due presentment of this Series C Senior Note for registration of
transfer, the Company, the Trustee and any agent of the Company or the Trustee
may treat the Person in whose name this Security is registered as the owner

                                       5
<PAGE>

hereof for all purposes, whether or not this Series C Senior Note be overdue,
and neither the Company, the Trustee nor any such agent shall be affected by
notice to the contrary.

     All terms used in this Series C Senior Note that are defined in the
Indenture shall have the meanings assigned to them in the Indenture.



                                       6
<PAGE>

                                  ABBREVIATIONS


The following abbreviations, when used in the inscription on the face of this
instrument, shall be construed as though they were written out in full according
to applicable laws or regulations:

TEN COM --                    as tenants in common

TEN ENT --                    as tenants by the entireties

JT TEN --                     as joint tenants with rights of survivorship and
                              not as tenants in common

UNIF GIFT MIN ACT --          ________________________________ Custodian for
                              (Cust)


                              ________________________________
                              (Minor)

                              Under Uniform Gifts to Minors Act of


                              ________________________________
                              (State)



Additional abbreviations may also be used though not on the above list.
______________________________________________________________


                                       7
<PAGE>

     FOR VALUE RECEIVED, the undersigned hereby sell(s) and transfer(s) unto
____________________ (please insert Social Security or other identifying number
of assignee).

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________

PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING POSTAL ZIP CODE OF
ASSIGNEE

the within Series C Senior Note and all rights thereunder, hereby irrevocably
constituting and appointing

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________



________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________


agent to transfer said Series C Senior Note on the books of the Company, with
full power of substitution in the premises.

Dated: __________________ __, ____


             ------------------------------------------------------


NOTICE:  The signature to this assignment must correspond with the name as
written upon the face of the within instrument in every particular without
alteration or enlargement, or any change whatever.

                                       8
<PAGE>

                                   EXHIBIT B
                         CERTIFICATE OF AUTHENTICATION



     This is one of the Securities of the series designated therein referred to
in the within-mentioned Indenture.

                                        BANK ONE TRUST COMPANY,
                                        NATIONAL ASSOCIATION,
                                        as Trustee


                                        By: ________________________________
                                            Authorized Officer



                                       9