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                                                                  Exhibit 10.(b)


                          CALCULATION AGENCY AGREEMENT

         AGREEMENT made on the 26th day of April, 1994 between THE FIRST
NATIONAL BANK OF BOSTON, a national banking association maintaining its
principal corporate trust office at 150 Royall Street, Canton, Massachusetts
02021 (the "Calculation Agent"), and USX CORPORATION, a Delaware corporation
having its principal place of business at 600 Grant Street, Pittsburgh,
Pennsylvania 15219-4776 (the "Issuer").

                             W I T N E S S E T H :

         WHEREAS, the Issuer proposes to issue and sell certain of its
securities designated as its Medium-Term Notes, Series C (the "Notes"); and
         WHEREAS, the Notes will be offered on a continuing basis by the Issuer
through The First Boston Corporation, Goldman, Sachs & Co., J. P. Morgan
Securities Inc., Morgan Stanley & Co. Incorporated, Salomon Brothers Inc and
Shearson Lehman Brothers, Inc., as agents (the "Agents"); and
         WHEREAS, the Notes are to be issued under an Indenture (the
"Indenture") dated as of March 15, 1993, between the Issuer and PNC Bank,
National Association, as Trustee (the "Trustee"); and
         WHEREAS, the Notes are to be distributed pursuant to the terms of a
Distribution Agreement dated April 26, 1994 (the "Distribution Agreement"),
among the Issuer and the Agents; and
         WHEREAS, for the purpose of appointing an agent to calculate the
interest rate based on the CD Rate, the Commercial Paper Rate, the Federal
Funds Effective Rate, LIBOR, the Prime Rate or the Treasury Rate, as
applicable, on the Notes bearing interest at a rate calculated with reference
to such interest rate bases (the "Floating Rate Notes"), the Issuer has
appointed The First National Bank of Boston as its Calculation Agent.
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         NOW, THEREFORE, in consideration of the premises, the mutual promises
hereinafter contained, and intending to be legally bound hereby, the
Calculation Agent and the Issuer hereby covenant and agree as follows:
         1.  Upon the terms and subject to the conditions contained herein, the
Issuer hereby appoints the Calculation Agent as its agent for the purpose of
calculating the interest rates on the Notes in the manner and at the times
provided herein, in the Floating Rate Notes, the Prospectus Supplement and the
related Pricing Supplements.
         2.  (i)  The Calculation Agent shall calculate the interest rate and
the amount of interest due on each of the Floating Rate Notes for each interest
accrual period and communicate the same to the Issuer upon the terms and
conditions contained herein and in the Notes.  The provisions of the Notes with
respect to interest rate calculations shall not be changed in any respect
without the express consent of the Calculation Agent.  The Issuer shall provide
the Calculation Agent with not less than two (2) business days' notice of the
calculation date on which a particular floating rate calculation is to be made
by the Calculation Agent, and the Calculation Agent shall notify the Issuer of
such floating rate calculation on such calculation date and may confirm such
calculation in writing within twenty-four (24) hours after so notifying the
Issuer; (ii) in no event shall the interest rate be less than the minimum
interest rate, if any, or higher than the maximum interest rate, if any,
designated in the applicable Floating Rate Note and in no event shall the
interest rate on the Notes be higher than the maximum rate permitted by New
York law as the same may be modified by United States law of general
application; (iii) the Calculation Agent shall calculate the amount of interest
payable on each Floating Rate Note in the manner and at the times set forth in
such Note; and (iv) as soon as practicable after each interest determination
date, the Calculation Agent will cause to be forwarded to the Issuer
information regarding the interest rates, the interest periods, the amount of
interest for each interest period and





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the relevant interest payment dates.  The Calculation Agent will, upon the
request of any holder of any Floating Rate Note, provide the interest rate
which will become effective as a result of a determination made on the most
recent interest determination date with respect to such Note.
         3.  The Calculation Agent shall exercise due care to determine the
interest rates on the Floating Rate Notes and shall communicate the same to the
Issuer, the Trustee, The Depository Trust Company and any paying agent
identified to it in writing as soon as practicable after each determination.
The Calculation Agent will, upon the request of the holder of any Floating Rate
Note, provide the interest rate then in effect with respect to such Floating
Rate Note and, if determined, the interest rate with respect to such Floating
Rate Note which will become effective on the next Interest Reset Date.  The
Calculation Agent and the Issuer agree to comply with the Administrative
Procedures attached hereto as Exhibit A.  No amendment to the provisions of the
Administrative Procedures relating to the duties or obligations of the
Calculation Agent hereunder may become effective without the prior written
consent of the Calculation Agent, which consent shall not be unreasonably
withheld.
         4.  The Calculation Agent accepts its obligations set forth herein,
upon the terms and subject to the conditions hereof, including the following,
to all of which the Issuer agrees:
             (a)  The Calculation Agent shall be entitled to such compensation
as may be agreed upon with the Issuer for all services rendered by the
Calculation Agent, and the Issuer promises to pay such compensation and to
reimburse the Calculation Agent for the reasonable out-of-pocket expenses
(including attorney's and other professional's fees and expenses) incurred by
it in connection with the services rendered by it hereunder upon receipt of
such invoices as the Issuer shall reasonably require.  The Issuer also agrees
to indemnify the Calculation Agent for, and to hold it





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harmless against, any and all loss, liability, damage, claim or expense
(including the costs and expenses of defending against any claim of liability)
incurred by the Calculation Agent that rises out of or in connection with its
accepting appointment as, or acting as, Calculation Agent hereunder, except
such as may result from the gross negligence, willful misconduct or bad faith
of the Calculation Agent or any of its agents or employees.  The Calculation
Agent shall incur no liability and shall be indemnified and held harmless by
the Issuer for, or in respect of, any actions taken, omitted to be taken or
suffered to be taken in good faith by the Calculation Agent in reliance upon
(i) the opinion or advice of legal advisors satisfactory to it or (ii) written
instructions from the Issuer.  The Calculation Agent shall not be liable for
any error resulting from the use of or reliance on a source of information used
in good faith and with due care to calculate any interest rate hereunder.  The
provisions of this Section shall survive the termination of this Agreement.
             (b)  In acting under this Agreement and in connection with the
Floating Rate Notes, the Calculation Agent is acting solely as agent of the
Issuer and does not assume any obligations or relationship of agency or trust
for or with any of the owners or holders of the Notes.
             (c)  The Calculation Agent shall be protected and shall incur no
liability for or in respect of any action taken or omitted to be taken or
anything suffered by it in reliance upon the terms of the Notes, any notice,
direction, certificate, affidavit, statement or other paper, document or
communication reasonably believed by it to be genuine and to have been approved
or signed by the proper party or parties.
             (d)  The Calculation Agent, its officers, directors, employees and
shareholders may become the owners of, or acquire any interest in, any Notes,
with the same rights that it or they would have if it were not the Calculation
Agent, and may





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engage or be interested in any financial or other transaction with the Issuer
as freely as if it were not the Calculation Agent.
             (e)  Neither the Calculation Agent nor its officers, directors,
employees, agents or attorneys shall be liable to the Issuer for any act or
omission hereunder, or for any error of judgment made in good faith by it or
them, except in the case of its or their gross negligence or willful
misconduct.
             (f)  The Calculation Agent may consult with counsel and the
written advice of such counsel or any opinion of counsel shall be full and
complete authorization and protection in respect of any action taken, suffered
or omitted by it hereunder in good faith and in reliance thereon.
             (g)  The Calculation Agent shall be obligated to perform such
duties and only such duties as are herein specifically set forth, and no
implied duties or obligations shall be read into this Agreement against the
Calculation Agent.
             (h)  Unless herein otherwise specifically provided, any order,
certificate, notice, request, direction or other communication from the Issuer
made or given by it under any provision of this Agreement shall be sufficient
if signed by any officer of the Issuer.
             (i)  The Calculation Agent may, upon obtaining the prior written
consent of the Issuer, perform any duties hereunder either directly or by or
through agents or attorneys, and the Calculation Agent shall not be responsible
for any misconduct or negligence on the part of any agent or attorney appointed
with due care by it hereunder.
             (j)  The Issuer will not, without first obtaining the prior
written consent of the Calculation Agent, make any change to the Notes in the
forms filed as exhibits to the Issuer's Current Report on Form 8-K dated April
26, 1994 if such change would





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materially and adversely affect the Calculation Agent's duties and obligations
under this Agreement.
         5.  (a)  The Calculation Agent may at any time resign as Calculation 
Agent by giving written notice to the Issuer of such intention on its part,
specifying the date on which its desired resignation shall become effective;
provided, however, that such date shall never be earlier than thirty (30) days
after the receipt of such notice by the Issuer, unless the Issuer agrees to
accept a shorter period of notice.  The Calculation Agent may be removed at any
time by the filing with it of any instrument in writing signed on behalf of the
Issuer and specifying such removal and the date when it is intended to become
effective.  Such resignation or removal shall take effect upon the date of the
appointment by the Issuer, as hereinafter provided, of a successor Calculation
Agent.  If a successor Calculation Agent has not been appointed five (5) days
prior to when any resignation or removal is to take effect, the Calculation
Agent may petition a court of competent jurisdiction to appoint a successor
Calculation Agent.  A successor Calculation Agent shall be appointed by the
Issuer by an instrument in writing signed on behalf of the Issuer and the
successor Calculation Agent.  Upon the appointment of a successor Calculation
Agent and acceptance by it of such appointment, the Calculation Agent so
superseded shall cease to be such Calculation Agent hereunder.  Upon its
resignation or removal, the Calculation Agent shall be entitled to the payment
by the Issuer of its compensation, if any is owed to it, for services rendered
hereunder and to the reimbursement of all reasonable out-of-pocket expenses
incurred in connection with the services rendered by it hereunder. 

             (b)  Any successor Calculation Agent appointed hereunder shall 
execute and deliver to its predecessor and to the Issuer an instrument
accepting such appointment hereunder, and thereupon such successor Calculation
Agent, without any further act, deed or conveyance, shall become vested with
all the authority, rights,





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powers, trusts, immunities, duties and obligations of such predecessor with
like effect as if originally named as such Calculation Agent hereunder, and
such predecessor, upon payment of its charges and disbursements then unpaid,
shall thereupon become obliged to transfer and deliver, and such successor
Calculation Agent shall be entitled to receive, copies of any relevant records
maintained by such predecessor Calculation Agent.
             (c)  Any corporation into which the Calculation Agent may be
merged, or any corporation with which the Calculation Agent may be
consolidated, or any corporation resulting from any merger or consolidation to
which the Calculation Agent shall sell or otherwise transfer all or
substantially all of its assets and business shall, to the extent permitted by
applicable law, be the successor Calculation Agent under this Agreement without
the execution or filing of any paper or any further act on the part of any of
the parties hereto.  Notice of any such merger, consolidation or sale shall
forthwith be given to the Issuer and the Trustee.
         6.  Any notice required to be given hereunder shall be delivered in
person, sent by letter or communicated by telephone (subject, in the case of
communication by telephone, to confirmation in writing dispatched within
twenty-four (24) hours), to the following:

If to the Issuer:              USX Corporation                
                               600 Grant Street               
                               Pittsburgh, Pennsylvania 15219 
                               telephone:  (412) 433-4419
                               telecopy:  (412) 433-4567
                               Attention:  Corporate Finance Department
                       
                       



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If to the Calculation Agent:   The First National Bank of Boston
                               Corporate Trust Administration
                               150 Royall Street, Mail Stop 45-02-15
                               Canton, Massachusetts 02021
                               telephone:  (617) 575-3145
                               telecopy:  (617) 575-2078
                               
and, in the case of:           The Depository Trust Company
                               Manager Announcements, Dividend Department,
                               The Depository Trust Company
                               7 Hanover Square - 22nd Floor
                               New York, New York  10004
                               telecopy:  (212) 709-1264 or (212) 709-1263,

or to any other address of which any party shall have notified the others in
writing as herein provided.  Any notice hereunder given by telephone, telecopy
or letter shall be effective upon receipt.
         7.  This Agreement shall be governed by, and construed in accordance
with, the laws of the State of New York.
         8.  This Agreement may be executed by each of the parties hereto in
any number of counterparts, each of which counterparts, when so executed and
delivered, shall be deemed to be an original and all such counterparts shall
together constitute one and the same agreement.
         9.  In the event of any conflict relating to the rights or obligations
of the Calculation Agent in connection with the calculation of the interest
rate on the Floating Rate Notes, the relevant terms of this Agreement shall
govern such rights and obligations.





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         10.  Terms used but not defined herein shall have the meanings
assigned to them in the Prospectus, dated April 8, 1994, and the Prospectus
Supplement thereto, dated April 26, 1994, relating to the Notes.
         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to
be executed as of the date first above written.

                                        USX CORPORATION


                                        By /s/  G. R. Haggerty
                                          -------------------------------------
                                          G. R. Haggerty
                                          Vice President & Treasurer



                                        THE FIRST NATIONAL BANK OF BOSTON


                                        By:
                                           ------------------------------------
                                        Title:





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