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                                                                      Exhibit 4I






                              COLUMBIA ENERGY GROUP
                (FORMERLY NAMED "THE COLUMBIA GAS SYSTEM, INC.")

                                       AND

                    MARINE MIDLAND BANK, AS RESIGNING TRUSTEE

                                       AND

            THE FIRST NATIONAL BANK OF CHICAGO, AS SUCCESSOR TRUSTEE


              INSTRUMENT OF RESIGNATION, APPOINTMENT AND ACCEPTANCE

                            Dated as of March 1, 1999
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                              COLUMBIA ENERGY GROUP
              INSTRUMENT OF RESIGNATION, APPOINTMENT AND ACCEPTANCE
                            Dated as of March 1, 1999

                                TABLE OF CONTENTS



PARTIES........................................................................1
                                                                           
RECITALS.......................................................................1
                                                                           
ARTICLE I.    TRUSTEE SUCCESSION...............................................2
                                                                           
Section 1.01  Resignation of Trustee...........................................2
Section 1.02  Appointment of Successor Trustee.................................2
Section 1.03  Acceptance and Assurances by Successor Trustee...................2
Section 1.04  Confirmatory Assignment..........................................2
Section 1.05  Costs and Expenses...............................................2
Section 1.06  Y2K..............................................................3
                                                                           
ARTICLE II.   MISCELLANEOUS PROVISIONS.........................................3
Section 2.01  Definitions; Use of Terms in this Agreement......................3
Section 2.02  Effect of Table of Contents and Headings.........................3
Section 2.03  Trust Indenture Act to Control...................................3
Section 2.04  Counterparts.....................................................3
Section 2.05  Company Warranties and Representations...........................3
                                                                           
TESTIMONIUM....................................................................4
                                                                           
SIGNATURES.....................................................................4
                                                                           
ACKNOWLEDGEMENTS...............................................................6
                                                                           
EXHIBIT A     Form of Notice to Holders........................................1
                                                                         

                                        i
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                                     PARTIES

      THIS INSTRUMENT OF RESIGNATION, APPOINTMENT AND ACCEPTANCE, dated as of
March 1, 1999 (herein "this Agreement") among COLUMBIA ENERGY GROUP, a Delaware
corporation (formerly named "The Columbia Gas System, Inc. and hereinafter
called the Company), MARINE MIDLAND BANK, a banking corporation and trust
company organized and existing under the laws of the State of New York, as
trustee under the Indenture referred to in the first recital hereof (hereinafter
called the Trustee), and THE FIRST NATIONAL BANK OF CHICAGO, a national banking
association (hereinafter called the Successor Trustee).

                                    RECITALS

      WHEREAS, the Company has heretofore executed and delivered to the Trustee
its Indenture dated as of November 28, 1995 and seven Supplemental Indentures
thereto, each dated as of November 28, 1995 (said Indenture being hereinafter
called the Original Indenture, and the Original Indenture together with all
indentures stated to be supplemental thereto, being hereinafter called the
Indenture); and

      WHEREAS, the Company has issued, and there are outstanding under the
Indenture,
$310,876,000 in aggregate principal amount of 6.39% Debentures Due
November 2000,
$281,530,000 in aggregate principal amount of 6.61% Debentures Due
November 2002,
$281,530,000 in aggregate principal amount of 6.80% Debentures Due
November 2005,
$281,530,000 in aggregate principal amount of 7.05% Debentures Due
November 2007,
$281,530,000 in aggregate principal amount of 7.32% Debentures Due
November 2010, 
$281,530,000 in aggregate principal amount of 7.42% Debentures Due 
November 2015, 
$281,530,000 in aggregate principal amount of 7.62% Debentures Due
November 2025; and

      WHEREAS, the Trustee wishes to resign and the Company wishes to appoint
the Successor Trustee as the Trustee's replacement; and

      WHEREAS, pursuant to Section 6.08 of the Indenture, the Successor Trustee
must deliver a written acceptance of its appointment to the Trustee and to the
Company; and

      WHEREAS, upon the terms of this Agreement, the Company is willing to take
action to permit the succession of the Successor Trustee to the trusteeship
under the Indenture; and

      WHEREAS, each of the parties hereto confirms to the others that its
execution and delivery of this Agreement and other necessary actions have been
duly authorized by, or pursuant to authority granted by, its Board of Directors
and have been duly approved to the extent required by law by the appropriate
governmental authorities; and

      WHEREAS, all acts and things necessary to make this Agreement, when
executed and delivered by each of the parties, a valid, binding and legal
agreement of such party have been done and performed.

      NOW, THEREFORE, in consideration of the premises, and of other good and
valuable consideration, the receipt whereof is hereby acknowledged, the parties
hereby agree as follows:
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                                   ARTICLE I.

                               TRUSTEE SUCCESSION

      Section 1.01 Resignation of Trustee. Pursuant to Section 6.08 of the
Indenture, the Trustee hereby resigns as trustee under the Indenture, effective
at the opening of business on March 1, 1999. The Company acknowledges receipt of
the notice of resignation from the Trustee required under said Section 6.08. The
Trustee covenants to and with the Company that all actions which have been and
will be taken by the Trustee in connection with the succession of the
trusteeship under the Indenture (including, without limitation, transfers of any
funds or other property held in trust under the Indenture) have been and will be
proper under the Indenture and fully protective of the respective interests of
the Company and the holders of Securities issued and to be issued under the
Indenture.

      Section 1.02 Appointment of Successor Trustee. Pursuant to Section 6.08 of
the Indenture, and in reliance upon the agreements and assurances of the Trustee
and Successor Trustee contained in this Agreement, the Company hereby appoints
the Successor Trustee as the new trustee under the Indenture. This appointment
shall be effective upon the effectiveness of the resignation of the Trustee
under the Indenture at the opening of business on March 1, 1999, and fully vests
the Successor Trustee with all the estates, properties, rights, powers, trusts,
duties and obligations of its predecessor in trust under the Indenture, with
like effect as if originally named as trustee thereunder. The Successor Trustee
shall mail to Securityholders notice (in the form of Exhibit A attached hereto)
of such appointment in the manner provided in Section 6.08 of the Indenture.

      Section 1.03 Acceptance and Assurances by Successor Trustee. The Successor
Trustee hereby accepts appointment as Successor Trustee under the Indenture, and
assumes all rights, powers, duties and obligations of the trustee under the
Indenture. In connection therewith, the Successor Trustee confirms its
eligibility and qualification under Section 6.10 of the Indenture. All funds or
other property received by the Successor Trustee from the Trustee or the
Company, either in the Successor Trustee's capacity as agent of the Trustee or
by virtue of the Successor Trustee's acceptance of appointment hereunder and the
conveyance made to it under Section 6.08 hereof, have been received and are held
by the Successor Trustee in trust under the Indenture in full protection of the
respective interests of the Company and the holders of Securities issued and to
be issued under the Indenture.

      Section 1.04 Confirmatory Assignment. In order more certainly to vest and
confirm the same in the Successor Trustee, the Trustee by these presents does
give, grant, bargain, sell, transfer, assign, convey and confirm unto the
Successor Trustee all the estates, properties, rights, powers, trusts, duties
and obligations of the Trustee as trustee under the Indenture, effective at the
opening of business on March 1, 1999.

      Section 1.05 Costs and Expenses. As between the Trustee and the Company,
the Company hereby agrees to pay or reimburse the Trustee for payment of all
reasonable termination costs and expenses relating to or arising out of the
succession of the trusteeship under the Indenture, including, without
limitation, reasonable legal fees and expenses, and expenses of giving required
notice of, and documenting of, the succession, and any expenses incurred in the
event of Securityholder action to appoint a trustee to replace the Successor
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Trustee under Section 6.08 of the Indenture. Notwithstanding the foregoing, with
respect to fees not related to and not arising out of the succession of the
trusteeship under the Indenture, the Trustee's 1999 annual fee shall be pro
rated up to and including the date of succession. The Successor Trustee's annual
fee for 1999 will likewise be pro rated, commencing with the day after the
succession.

      Section 1.06 Y2K. Consistent with the recommendations of the Comptroller
of the Currency, all financial institutions were required to have their year
2000 conversions and unit testing associated with such conversions completed by
December 31, 1998, thereby allowing internal and external interface testing,
including testing with customers, during 1999 to ensure that all systems are
working properly and reliably. The Successor Trustee represents that it has
completed unit testing for major systems which support the services being
contemplated in this Agreement related to the year 2000 century date change.
This effort is part of a vigorous and comprehensive project to inventory,
assess, renovate or replace and test affected systems. The system(s) which
support the service being offered in this Agreement are part of that effort.


                                   ARTICLE II.

                            MISCELLANEOUS PROVISIONS

      Section 2.01 Definitions; Use of Terms in this Agreement. The use of terms
and expressions herein is in accordance with the definitions and constructions
contained in the Indenture.

      Section 2.02 Effect of Table of Contents and Headings. The Table of
Contents and headings of the different Articles and Sections of this Agreement
are inserted for convenience of reference, and are not to be taken to be any
part of those provisions, or to control or affect the meaning, construction or
effect of the same.

      Section 2.03 Trust Indenture Act to Control. If any provision of this
Agreement limits, qualifies or conflicts with the duties imposed by any of
Sections 310 to 317, inclusive, of the Trust Indenture Act of 1939, as amended
by the Trust Indenture Reform Act of 1990, through operation of Section 318(c),
such imposed duties shall control.

      Section 2.04 Counterparts. This Agreement may be executed in any number of
counterparts and on separate counterparts, each of which shall be deemed an
original; and all said counterparts executed and delivered, each as an original,
shall constitute but one and the same instrument, which shall for all purposes
be sufficiently evidenced by any such original counterpart.

      Section 2.05 Company Warranties and Representations. The Company hereby
represents and warrants to the Successor Trustee that:

      (a) This Agreement has been duly and validly authorized, executed, and
      delivered by the Company; and

      (b) The Company is unaware of any "Event of Default" (as defined in
      Section 5.01 of the Indenture).
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                                   TESTIMONIUM

      IN WITNESS WHEREOF, Columbia Energy Group has caused this Agreement to be
executed in its corporate name by its Chairman of the Board or its President or
one of its Vice Presidents or its Treasurer or one of its Assistant Treasurers,
and its corporate seal to be hereunto affixed and to be attested by its
Secretary or one of its Assistant Secretaries, and Marine Midland Bank has
caused this Agreement to be executed in its corporate name and its corporate
seal to be hereunto affixed by one of its Vice Presidents and to be attested by
one of its Assistant Vice Presidents, and The First National Bank of Chicago has
caused this Agreement to be executed in its corporate name and its corporate
seal to be hereunto affixed by one of its Vice Presidents and to be attested by
one of its Assistant Vice Presidents, all as of March 1, 1999.


                                   SIGNATURES


                                        COLUMBIA ENERGY GROUP



Attest:_____________________________    By:____________________________
       Secretary



[CORPORATE SEAL]





                                        MARINE MIDLAND BANK, as Trustee



Attest:_____________________________    By:____________________________



[CORPORATE SEAL]
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                                        THE FIRST NATIONAL BANK OF
                                        CHICAGO, as Successor Trustee



Attest:_____________________________    By:____________________________



[CORPORATE SEAL]
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                                ACKNOWLEDGEMENTS


COMMONWEALTH OF VIRGINIA            )
                                    )     ss:
CITY/COUNTY OF _____________        )

      On this _____ day of ___________________, ______, before me personally
came __________________, to me known, who, being by me duly sworn, did depose
and say that he resides at __________________________________________; that he
is _______________ of Columbia Energy Group, one of the corporations described
in and which executed the foregoing instrument; that he knows the seal of said
corporation; that the seal affixed to said instrument bearing the corporate name
of said corporation is such corporate seal; that it was so affixed by order of
the Board of Directors of said corporation; and that he signed his name thereto
by like order.


                                        ___________________________________
                                        Notary Public


                                        ___________________________________
                                        My commission expires


STATE OF NEW YORK                   )
                                    )     ss:
COUNTY OF NEW YORK                  )

      On the _____ day of ___________________, ______, before me personally came
__________________, to me known, who, being by me duly sworn, did depose and say
that he resides at __________________________________________; that he is
_______________ of Marine Midland Bank, one of the corporations described in and
which executed the foregoing instrument; that he knows the seal of said
corporation; that the seal affixed to said instrument bearing the corporate name
of said corporation is such corporate seal; that it was so affixed by authority
of the Board of Directors of said corporation; and that he signed his name
thereto by like authority.


                                        ___________________________________
                                        Notary Public


                                        ___________________________________
                                        My commission expires
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STATE OF _____________________      )
                                    )     ss:
CITY/COUNTY OF ______________       )

      On the _____ day of ___________________, ______, before me personally came
__________________, to me known, who, being by me duly sworn, did depose and say
that he resides at __________________________________________; that he is
_______________ of The First National Bank of Chicago, one of the corporations
described in and which executed the foregoing instrument; that he knows the seal
of said corporation; that the seal affixed to said instrument bearing the
corporate name of said corporation is such corporate seal; that it was so
affixed by authority of the Board of Directors of said corporation; and that he
signed his name thereto by like authority.


                                        ___________________________________
                                        Notary Public


                                        ___________________________________
                                        My commission expires
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                                    EXHIBIT A

                               (Notice to Holders)

                            NOTICE TO THE HOLDERS OF

                              COLUMBIA ENERGY GROUP
                 (FORMERLY NAMED THE COLUMBIA GAS SYSTEM, INC.)
                        DEBENTURES DUE _________________
                                  CUSIP #______
                               (THE "DEBENTURES")

NOTE: THIS NOTICE CONTAINS IMPORTANT INFORMATION THAT IS OF INTEREST TO THE
BENEFICIAL OWNERS OF THE SUBJECT DEBENTURES. IF APPLICABLE, ALL DEPOSITORIES,
CUSTODIANS AND OTHER INTERMEDIARIES RECEIVING THIS NOTICE ARE REQUESTED TO
EXPEDITE RE-TRANSMITTAL TO SUCH BENEFICIAL OWNERS IN A TIMELY MANNER.

      The First National Bank of Chicago ("First Chicago"), on behalf of
Columbia Energy Group (formerly named The Columbia Gas System, Inc.) (the
"Company"), hereby notifies holders of the Debentures of the resignation of
Marine Midland Bank, as trustee (the "Resigning Trustee") under the Indenture
dated as of November 28, 1995, as supplemented by seven Supplemental Indentures
thereto dated as November 28, 1995 (collectively, the "Indenture") between the
Company and the Resigning Trustee, under which Indenture the Debentures were
issued.

      The Company has appointed The First National Bank of Chicago as successor
trustee (the "Successor Trustee") under the Indenture, whose corporate trust
office is located at One First National Plaza, Suite 0126, Chicago, Illinois
60670-0126, which appointment has been accepted and became effective at the
opening of business on March 1, 1999.

      The Successor Trustee, on behalf of the Company, also hereby notifies
holders of the Debentures of the resignation of the Resigning Trustee as
Registrar and Paying Agent effective at the opening of business on March 1,
1999, and the simultaneous appointment of the Successor Trustee as Registrar and
Paying Agent. Effective March 1, 1999, the address for the Registrar and Paying
Agent will be:

            The First National Bank of Chicago
            One First National Plaza
            Suite 0126
            Chicago, Illinois  60670-0126
            Attn:  Corporate Trust Services Division

      The above-referenced CUSIP number is for convenience only and neither the
Resigning Trustee, the Successor Trustee nor the Company shall be responsible
for any error of any nature relating to the CUSIP number.

            By: The First National Bank of Chicago,
                as Successor Trustee


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