
                                               EXECUTION COPY



                AMENDMENT TO RIGHTS AGREEMENT

                    AMENDMENT No. 3 dated as of November 14,
               1998 (this "Amendment"), to the Rights
               Agreement dated as of September 22, 1987 (as
               amended, the "Rights Agreement"), between
               CalMat Co., a Delaware corporation (the
               "Company"), and First Chicago Trust Company of
               New York, as Rights Agent (the "Rights
               Agent"). All capitalized terms not otherwise
               defined herein shall have the meaning ascribed
               to such terms in the Rights Agreement.

          WHEREAS Vulcan Materials Company, a New Jersey
corporation ("Parent"), ALB Acquisition Corporation, a
Delaware corporation and a wholly owned subsidiary of Parent
("Merger Sub") and the Company have proposed to enter into an
Agreement and Plan of Merger to be dated the date hereof (the
"Merger Agreement");

          WHEREAS the Company desires to amend the Rights
Agreement to, among other things, render the Rights
inapplicable to the Merger (as defined in the Merger
Agreement), the Offer (as defined in the Merger Agreement)
and the other transactions contemplated by the Merger
Agreement;

          WHEREAS the Company deems this Amendment to the
Rights Agreement to be necessary and desirable and in the
best interests of the holders of the Rights and has duly
approved this Amendment; and

          WHEREAS Section 26 of the Rights Agreement permits
the Company and the Rights Agent at any time to amend the
Rights Agreement in the manner provided herein and provides
that this Amendment shall become effective immediately upon
execution by the Company and the Rights Agent.

          NOW, THEREFORE, the Company hereby amends the
Rights Agreement as follows:

          1. Section 1 of the Rights Agreement is hereby
amended by adding the following new paragraph as the last
paragraph of Section 1:

          "Notwithstanding anything in this Agreement to the
     contrary, none of Vulcan Materials Company, a New Jersey
     corporation ("Parent") or ALB Acquisition Corporation, a
     Delaware corporation and a wholly owned subsidiary of
     Parent ("Merger Sub") or any of their respective
     Affiliates or Associates shall become an Acquiring
     Person, no Distribution Date shall occur, no


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     Rights shall separate from the Common Shares or
     otherwise become exercisable and no adjustment shall be
     made pursuant to Section 11 or 13, in each case, solely
     by reason of (i) the announcement or commencement of the
     Offer (as defined in the Agreement and Plan of Merger
     dated as of November 14, 1998 (the "Merger Agreement")
     among Parent, Merger Sub and the Company), (ii) the
     acquisition of Common Shares pursuant to the Offer,
     (iii) the announcement, approval, execution or delivery
     of the Merger Agreement or (iv) the consummation of the
     Merger (as defined in the Merger Agreement)."

          2. Section 3(a) of the Rights Agreement is hereby
amended by deleting the first sentence thereof and replacing
it with the following sentence:

     "Until the earlier of (i) the tenth day after the Shares
     Acquisition Date or (ii) the close of business on such
     date, if any, as may be designated by the Board of
     Directors of the Company following the commencement of,
     or first public announcement of the intent of any Person
     (other than the Company, any Subsidiary of the Company,
     any employee benefit plan of the Company or any
     Subsidiary of the Company or any entity holding shares
     of capital stock of the Company for or pursuant to the
     terms of any such plan, in its capacity as an agent or
     trustee for any such plan) to commence, a tender or
     exchange offer the consummation of which would result in
     any Person becoming the Beneficial Owner of Common
     Shares aggregating more than 30% or more of the then
     outstanding Common Shares of the Company (including any
     such date which is after the date of this Agreement; the
     earlier of (i) and (ii) being herein referred to as the
     "Distribution Date"), (x) the Rights will be evidenced
     (subject to the provisions of paragraph (b) of this
     Section 3) by certificates for Common Shares registered
     in the names of the holders thereof (which certificates
     for Common Shares shall also be deemed to be Right
     Certificates) and not by separate Right Certificates,
     and (y) the right to receive the Right Certificates will
     be transferable only in connection with the transfer of
     Common Shares."

          3. The Rights Agreement shall not otherwise be
supplemented or amended by virtue of this Amendment, but
shall remain in full force and effect as amended hereby.


<PAGE>


          4. The Rights Agent is hereby directed, immediately
prior to any Distribution Date, to make such amendments to
the form of Right Certificate attached to the Rights
Agreement to conform with the Rights Agreement as amended by
this Amendment and any subsequent amendments thereto.

          5. This Amendment shall be governed by and
construed in accordance with the law of the State of Delaware
applicable to contracts to be made and performed entirely
within such State.

          6. This Amendment may be executed in any number of
counterparts and each of such counterparts shall for all
purposes be deemed to be an original, and all such
counterparts shall together constitute but one and the same
instrument.

          7. This Amendment shall be deemed effective as of
the date first written above.

          IN WITNESS WHEREOF, the Company has executed this
Amendment as of the date and year first above written.

                               CalMat Co.,

                               by
                                 --------------------------------
                                 /s/ A. Frederick Gerstell
                                 Name:  A. Frederick Gerstell
                                 Title: Chairman and Chief
                                        Executive Officer


                               First Chicago Trust Company of
                               New York, as Rights Agent,

                               by
                                 --------------------------------
                                 /s/ Joanne Gorostiola
                                 Name:  Joanne Gorostiola
                                 Title: Assistant Vice
                                        President

