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                            [Form of Senior Security]

                                                                     Exhibit 4.2

         Unless this certificate is presented by an authorized representative
of the Depository Trust Company, a New York corporation ("DTC") 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 is
requested by an authorized representative of DTC (and any payment is made to
Cede & Co. or to such other entity as is requested by an authorized
representative of DTC), 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.

                                  ASHLAND INC.
          [     ]% Debenture Due [                  ]

REGISTERED                                                       CUSIP [      ]
No. [      ]                                                     $ [          ]

ASHLAND INC., a corporation duly organized and existing under the laws of the
Commonwealth of Kentucky (herein called the "Company"), for value received,
hereby promises to pay to Cede & Co., or registered assigns, at the office or
agency of the Company in Cincinnati, Ohio, the principal sum of [      ] on
[     ], in such coin or currency of the United States of America as at the
time of payment shall be legal tender for the payment of public and private
debts, and to pay interest, semiannually on May 15 and November 15 of each year,
commencing on May 15, [      ], on said principal sum at said office or agency,
in like coin or currency, at the rate per annum specified in the title of this
Debenture, from the May 15 or the November 15, as the case may be, next
preceding the date of this Debenture to which interest has been paid, unless
the date hereof is a date to which interest has been paid, in which case from
the date of this Debenture, or unless no interest has been paid on these
Debentures, in which case from November 15, [      ], until payment of said
principal sum has been made or duly provided for; provided, however, that
payment of interest may be made at the -------- ------- option of the Company
by check mailed to the address of the person entitled thereto as such address
shall appear on the Debt Security Register. Notwithstanding the foregoing, if
the date hereof is after the first day of any May or November, as the case may
be, and before the following May 15 or November 15, this Debenture shall bear
interest from such May 15 or November 15; provided, however, that if the Company
shall default in the payment of interest -------- ------- due on such May 15
or November 15, then this Debenture shall


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bear interest from such May 15 or November 15; provided, however, that if the
Company shall default in the payment of interest due on such May 15 or November
15, then this Debenture shall bear interest from the next preceding May 15 or
November 15, to which interest has been paid or, if no interest has been paid on
these Debentures, from November 15, [ ]. The interest so payable on any May 15
or November 15, will, subject to certain exceptions provided in the Indenture
dated as of [ ] (herein called the "Indenture") duly executed and delivered by
the Company to U.S. Bank, National Association, Trustee (herein called the
"Trustee") be paid to the person in whose name this Debenture is registered at
the close of business on the May 1 or November 1, as the case may be, next
preceding such May 15 or November 15 (herein called the "Regular Record Date")
whether or not a Business Day. Any such interest which is payable, but is not so
punctually paid or duly provided for, shall forthwith cease to be payable to the
registered Holder on such Regular Record Date and may be paid either to the
Person in whose name this Debenture (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 Debentures 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
Debentures may be listed and upon such notice as may be required by such
exchange, if such manner of payment shall be deemed practical by the Trustee,
all as more fully provided in the Indenture.

          This Debenture is one of a duly authorized issue of debentures, notes,
bonds or other evidence of indebtedness of the Company (hereinafter called the
"Securities") of the series hereinafter specified, all issued or to be issued
under and pursuant to the Indenture, to which Indenture and all indentures
supplemental thereto reference is hereby made for a description of the rights,
limitations of rights, obligations, duties and immunities thereunder of the
Trustee, the Company and the holders of the Securities.

          The Securities shall be issued in one or more series, which different
series may be issued in various aggregate principal amounts, may mature at
different times, may bear interest (if any) at different rates, may be subject
to different redemption provisions (if any), may be subject to different
sinking, purchase or analogous funds (if any), may be subject to different
covenants and Events of Default and may otherwise vary as provided in the
Indenture. This Debenture is one of a series of Securities of the Company issued
pursuant to the Indenture designated as the [   ]% Debentures Due [         ],
(herein

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called the "Debentures"), limited in aggregate principal amount to $[        ].

          In case an Event of Default, as defined in the Indenture, with respect
to the Debentures shall have occurred and be continuing, the principal hereof
may be declared, and upon such declaration shall become, due and payable, in the
manner, with the effect and subject to the conditions provided in the Indenture.

          Subject to a number of important qualifications and exceptions set
forth in the Indenture, the Indenture provides that neither the Company nor any
Subsidiary (as defined in the Indenture) will (i) issue, assume or guarantee any
notes, bonds, debentures or other similar evidences of indebtedness for money
borrowed secured by a mortgage, lien, pledge or other encumbrance upon any real
or personal property located in the continental United States of America without
effectively providing that the Securities will be secured equally and ratably
with (or, at the option of the Company, prior to) such indebtedness so long as
such indebtedness shall be so secured or (ii) enter into any Sale and Lease-Back
Transactions (as defined in the Indenture).

          The Indenture also provides that the Company at its option (a) will be
Discharged (as such term is defined in the Indenture) from any and all
obligations in respect of the Securities (except for certain obligations to
register the transfer or exchange of Securities, replace stolen, lost or
mutilated Securities, maintain paying agencies and hold moneys for payment in
trust) or (b) need not comply with certain restrictive covenants of the
Indenture, if there is deposited with the Trustee, in the case of Securities
denominated U.S. dollars, U.S. Government Obligations (as defined in the
Indenture), or in the case of Securities denominated in a foreign currency,
Foreign Government securities (as defined in the Indenture), which through the
payment of interest thereon and principal thereof in accordance with their terms
will provide money or a combination of money and U.S. Government Obligations or
Foreign Government Securities, as the case may be, in an amount sufficient to
pay in the currency, currencies or currency unit or units in which the
Securities are payable all the principal of, and interest on, the Securities on
the dates such payments are due in accordance with the terms of the Securities.

          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

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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 not less than 66-2/3% in principal amount of the Securities at the
time Outstanding of each series to be affected. The Indenture also permits the
Holders of a majority in principal amount of the Securities at the time
Outstanding of each series on behalf of the Holders of all Securities of such
series, to waive compliance by the Company with certain provisions of the
Indenture and certain past defaults and their consequences with respect to such
series under the Indenture. Any such consent or waiver by the Holder of this
Debenture shall be conclusive and binding upon such Holder and upon all future
Holders of this Debenture and any Debentures which may be issued in exchange
herefor, irrespective of whether or not any notation thereof is made upon this
Debenture or such other Debentures.

          As set forth in, and subject to, the provisions of the Indenture, no
Holder of any Security of this series will have any right to institute any
proceeding with respect to the Indenture or for any remedy thereunder, unless
such Holder shall have previously given to the Trustee written notice of a
continuing Event of Default with respect to this series, the Holders of not less
than 25% in principal amount of the Outstanding Securities of this series shall
have made written request, and offered reasonable indemnity, to the Trustee to
institute such proceeding as trustee, the Trustee shall not have received from
the Holders of a majority in principal amount of the Outstanding Securities of
this series a direction inconsistent with such request and the Trustee shall
have failed to institute such proceeding within 60 days; provided, however, that
                                                         --------  -------
such limitations do not apply to a suit instituted by the Holder hereof for the
enforcement of payment of the principal of (and premium, if any) of interest on
this Security on or after the respective due dates expressed herein.

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

The Debentures are issuable in registered form without coupons in denominations
of $1,000 and any integral multiple of $1,000. At the office or agency of the
Company in Cincinnati, Ohio, and in the manner and subject to the limitations
provided in the

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                                                                               5

Indenture, but without the payment of any service charge, Debentures may be
exchanged for a like aggregate principal amount of Debentures of other
authorized denomination.

          The Debentures may not be redeemed prior to maturity.

          Upon due presentment for registration of transfer of this Debenture at
the office or agency of the Company in Cincinnati, Ohio, a new Debenture or
Debentures of authorized denominations for an equal aggregate principal amount
will be issued to the transferee in exchange therefor, subject to the
limitations provided in the Indenture, without charge except for any tax or
other governmental charge imposed in connection therewith.

          Prior to due presentment of this Debenture for registration of
transfer, the Company, the Trustee and any agent of the Company or the Trustee
may deem and treat the registered holder hereof as the absolute owner of this
Debenture (whether or not this Debenture shall be overdue and notwithstanding
any notation of ownership or other writing hereon), for the purpose of receiving
payment hereof, or on account hereof, and for all purposes, and neither the
Company nor the Trustee nor any agent of the Company or the Trustee shall be
effected by any notice to the contrary.

          Terms used herein which are defined in the Indenture shall have the
respective meanings assigned thereto in the Indenture.

          The Indenture and this Debenture shall be governed by and construed in
accordance with the laws of the State of New York.

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          This Debenture shall not be valid or become obligatory for any
purposes until the certificate of authentication hereon shall have been signed
by the Trustee under the Indenture.

          IN WITNESS WHEREOF, ASHLAND INC., has caused this instrument to be
duly executed under its corporate seal.

Dated:  [                  ]


                                                ASHLAND INC.,

                                                   by_________________________


[SEAL]                                          Attest:


                                                  by__________________________


                     TRUSTEE'S CERTIFICATE OF AUTHENTICATION

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

                                                U.S. BANK, National Association,
                                                as Trustee,

                                                  by__________________________
                                                           Authorized Officer