EXHIBIT 10.1
           Amendment No. 1 to Agreement and Plan of Merger dated as of
              May 17, 2000 by and between NBT Bancorp Inc. and BSB
                                  Bancorp, Inc.




                    AMENDMENT TO AGREEMENT AND PLAN OF MERGER

         AMENDMENT  TO  AGREEMENT  AND PLAN OF MERGER  dated as of May 17,  2000
(this  "Amendment"),  by and between NBT BANCORP  INC.,  a Delaware  corporation
("NBT"),  and BSB  BANCORP,  INC.,  a Delaware  corporation  ("BSB")  (at times,
referred to herein as the "PARTY" or the "PARTIES").

                                   BACKGROUND

         A. The Parties  entered into that certain  Agreement and Plan of Merger
dated as of April 19,  2000  (the  "AGREEMENT"),  pursuant  to which BSB will be
merged  with and into NBT,  subject  to the terms and  conditions  thereof  (the
"MERGER").

         B. The Agreement  provides that the Parties will cause BSB Bank & Trust
Company, a New York-chartered commercial bank and trust company headquartered in
Binghamton,  New York and wholly owned  subsidiary of BSB ("BSB BANK"),  and NBT
Bank,  National  Association,  a national banking  association  headquartered in
Norwich, New York and wholly owned subsidiary of NBT ("NBT BANK"), to enter into
a bank plan of  merger  providing  for the  merger of BSB Bank with and into NBT
Bank (the "BANK  MERGER"),  and specifies the Parties'  intention  that the Bank
Merger be consummated immediately after consummation of the Merger.

         C. The Parties now wish to amend the  Agreement to specify the Parties'
intention  that  the  Bank  Merger  be  consummated   simultaneously   with  the
consummation of the Merger and to make certain other changes to the Agreement in
connection  therewith,  and to extend the time for the Parties to determine  the
number  of  directors  of the  Resulting  Bank  and for the  designation  of the
directors of the Resulting Bank by NBT and BSB to no later than 40 Business Days
following  the date of the  Agreement.  Capitalized  terms used but not  defined
herein shall have the meanings given to them in the Agreement.

         NOW,  THEREFORE,  in  consideration  of the  foregoing  and the  mutual
covenants and  agreements  herein  contained,  and intending to be legally bound
hereby, the Parties agree as follows:

         1.       AMENDMENT.

                 (a)  The fourth recital of the Agreement is amended and
                 restated in its entirety

as follows:

                           WHEREAS, prior to consummation of the Merger, NBT and
                  BSB will cause BSB Bank & Trust Company,  a New York-chartered
                  commercial bank and trust company headquartered in Binghamton,
                  New York and wholly owned subsidiary of BSB ("BSB BANK"),  and
                  NBT Bank, National Association, a national banking association



                  head-quartered   in  Norwich,   New  York  and  wholly   owned
                  subsidiary of NBT ("NBT  BANK"),  to enter into a bank plan of
                  merger,  in the form  attached  hereto as EXHIBIT A (the "BANK
                  MERGER AGREEMENT"),  providing for the merger of BSB Bank with
                  and into NBT Bank (the "BANK MERGER"), with NBT Bank being the
                  resulting bank of the Bank Merger (the "RESULTING  BANK"), and
                  it  is   intended   that  the  Bank   Merger  be   consummated
                  simultaneously with consummation of the Merger; and

                  (b)  Exhibit A to the Agreement is amended and restated in its
                  entirety in the form attached hereto as Exhibit A.

                  (c)  Section 1.07 of the Agreement is amended and restated in
                  its entirety as follows:

                           At the Effective  Time, the board of directors of the
                  Resulting  Bank shall  consist of the chairman of the board of
                  directors of the Surviving Corporation, who shall serve as the
                  chairman of the board of the Resulting Bank, and eight, ten or
                  twelve other  persons,  half of whom will be designated by NBT
                  and half of whom will be designated by BSB. The number of such
                  other  persons shall be agreed upon by NBT and BSB, and in the
                  absence of timely  agreement  such number shall be set at ten.
                  The number of directors  and the  selection of directors to be
                  designated  by NBT and  BSB  under  this  paragraph  shall  be
                  determined  and made no later than 40 Business Days  following
                  the date of this Agreement and shall be noted on Schedule 1.07
                  to be  attached  to and  deemed  a  part  of  this  Agreement,
                  provided,  that the president of the  Resulting  Bank shall be
                  one of the directors so designated by NBT.

                  (d)  Section 2.05(b)(iii) of the Agreement is amended and
                  restated in its entirety as follows:

                           (iii)    courtesy notice of the Bank Merger to the
                           New York State Banking Department (the "NYSBD");


                  (e)  Section 3.05(b)(iii) of the Agreement is amended and
                  restated in its entirety as follows:

                           (iii)    courtesy notice of the Bank Merger to the
                           NYSBD;

                  (f)  Section 8.02 of the Agreement is amended and restated in
                  its entirety as follows:

                           The  representations,  warranties  and  agreements in
                  this Agreement  shall  terminate at the Effective Time or upon
                  the  termination  of this  Agreement  pursuant to Article VII,
                  except  that the  agreements  set  forth in  Article  I and in
                  Sections 5.06,  5.07 and 5.08 shall survive the Effective Time


                  indefinitely  and those set forth in Sections  5.03(c),  5.11,
                  7.02  and  Article  VIII  hereof  shall  survive   termination
                  indefinitely.


         2.       REPRESENTATIONS AND WARRANTIES.  Each of the Parties hereby
represents and warrants to the others as follows:

                  (a) It has the power to execute and deliver this Amendment and
has taken all  necessary  action to authorize the execution and delivery of this
Amendment and the performance of the Agreement as amended hereby;

                  (b) The  execution  and  delivery  of this  Amendment  and the
performance of the Agreement as amended hereby will not violate any provision of
any  applicable  law or  regulation  or of any writ or  decree  of any  court or
governmental  instrumentality,  or its certificate or articles of incorporation,
by-laws, or other similar organizational documents.

         3.       REAFFIRMATION.  Except as amended hereby, all of the terms,
covenants and conditions of the Agreement are ratified, reaffirmed and confirmed
and shall continue in full force and effect as therein written.

         4.       BINDING  EFFECT.  This  Amendment  shall be binding  upon and
inure solely to the benefit of each Party hereto, and nothing in this Amendment,
express or implied,  is intended  to or shall  confer upon any other  person any
right,  benefit  or remedy of any nature  whatsoever  under of by reason of this
Amendment.

         5.       COUNTERPARTS. This Amendment may be executed in one or more
counterparts, and by the different Parties hereto in separate counterparts, each
of which when executed shall be deemed to be an original but all of which taken
together shall constitute one and the same agreement.

         6.       GOVERNING LAW.  This Amendment shall be governed by, and
construed in  accordance  with the laws of the State of Delaware,  regardless of
the laws that might otherwise govern under applicable principles of conflicts of
law.

         IN  WITNESS  WHEREOF,  NBT and BSB have  caused  this  Amendment  to be
executed  as of the  date  first  written  above by  their  respective  officers
thereunto duly authorized.

                                  NBT BANCORP INC.


                                  By:    /S/ DARYL R. FORSYTHE
                                         ----------------------
                                  Name:  Daryl R. Forsythe
                                  Title: President and Chief Executive Officer


                                  BSB BANCORP, INC.


                                  By:    /S/ THOMAS L. THORN
                                         ----------------------
                                  Name:  Thomas L. Thorn
                                  Title: Acting President and Chief
                                         Executive Officer



                                                                       EXHIBIT A

                               BANK PLAN OF MERGER

                  This Bank Plan of Merger  (this  "Plan of Merger") is made and
entered into as of the ____ day of __________,  2000 between NBT BANK,  NATIONAL
ASSOCIATION,  a national banking association located in Norwich,  New York ("NBT
Bank") and BSB Bank & Trust Company,  a New  York-chartered  commercial bank and
trust company located in Binghamton, New York ("BSB Bank").


                                   WITNESSETH

                  WHEREAS, NBT Bancorp Inc., a Delaware corporation ("NBT"), and
BSB  Bancorp,  Inc.,  a  Delaware  corporation  ("BSB"),  have  entered  into an
Agreement and Plan of Merger, dated as of April ____, 2000 (the "Agreement");

                  WHEREAS,  NBT Bank is a wholly owned subsidiary of NBT and BSB
Bank is a wholly owned subsidiary of BSB;


                  WHEREAS,  BSB will  merge  with and into NBT  pursuant  to the
terms of the Agreement (the  "Merger"),  and  simultaneously  therewith BSB Bank
will merge with and into NBT Bank pursuant to this Plan of Merger, with NBT Bank
surviving as the resulting bank; and


                  WHEREAS,   NBT  Bank  has  _______   shares  of  common  stock
outstanding, $1.00 par value per share, and BSB Bank has 1,000 shares of capital
stock outstanding, $1.00 par value per share.


                  NOW,  THEREFORE,  in  consideration  of the  premises  and the
mutual  covenants and  agreements  contained  herein and in the  Agreement,  the
parties hereto do mutually agree, intending to be legally bound, as follows:

                                    ARTICLE 1
                                   DEFINITIONS

                  Except as otherwise provided herein, the capitalized terms set
forth below shall have the following meanings:


         1.1      "BANK MERGER" shall mean the merger of BSB Bank with and into


NBT Bank as provided in Section 2.1 of this Plan of Merger.


         1.2      "EFFECTIVE TIME" shall mean the date and time at which the
Bank Merger becomes effective as provided in Section 2.2 hereof.


         1.3      "MERGING BANKS" shall mean, collectively, BSB Bank and NBT
Bank.


         1.4      "OCC" shall mean the Office of the Comptroller of the
Currency.


         1.5      "RESULTING BANK" shall refer to NBT Bank as the surviving bank
in the Bank Merger.

                                    ARTICLE 2
                            TERMS OF THE BANK MERGER
2.1  THE BANK MERGER
                  (a)  Subject  to the  terms  and  conditions  set forth in the
Agreement,  and in  accordance  with the National  Bank Act and the Federal Bank
Merger Act and the  regulations of the OCC promulgated  thereunder,  and the New
York Banking Law and the  regulations  of the New York Banking Board and the New
York  Superintendent  of Banks,  at the Effective Time, BSB Bank shall be merged
with and into NBT Bank  pursuant to and upon the terms set forth in this Plan of
Merger. NBT Bank shall continue as the Resulting Bank in the Bank Merger and the
separate existence of BSB Bank shall cease.


                  (b) As a result of the Bank Merger,  (i) each share of capital
stock, par value $1.00 per share, of BSB Bank issued and outstanding immediately
prior to the  Effective  Time shall be  canceled,  and (ii) each share of common
stock, par value $1.00 per share, of NBT Bank issued and outstanding immediately
prior to the  Effective  Time  shall  remain  issued and  outstanding  and shall
constitute  the only  shares of common  stock of the  Resulting  Bank issued and
outstanding immediately after the Effective Time.


                  (c) On and after the  Effective  Time,  the Bank Merger  shall
have the  effects  set forth in  Section  215a(c) of the  National  Bank Act and
Section 602 of the New York Banking Law.

2.2  EFFECTIVE TIME
                  The Bank Merger  shall  become  effective at the same date and
time as the Merger becomes  effective  pursuant to Section 1.02 of the Agreement
(the "Effective Time").

2.3  NAME OF THE RESULTING BANK
                  The name of the Resulting Bank shall be
"________________________."

2.4  ARTICLES OF ASSOCIATION
                  On and after the Effective  Time,  the Articles of Association
of NBT Bank shall be the Articles of Association of the Resulting  Bank,  unless
and until amended in accordance  with  applicable  law except that the corporate



title shall be changed in accordance with Section 2.3 of this Plan of Merger and
the main office shall be changed in accordance  with Section 2.8 of this Plan of
Merger.

2.5  BYLAWS
                  On and after the Effective  Time, the bylaws of NBT Bank shall
be the bylaws of the Resulting Bank, unless and until amended in accordance with
applicable  law except that the  corporate  title shall be changed in accordance
with Section 2.3 of this Plan of Merger.

2.6  DIRECTORS AND OFFICERS
         The directors and executive  officers of the Resulting Bank shall be as
set forth in ANNEX 1 hereto.

2.7  CORPORATE ACTION
                  This Plan of Merger and the  consummation of the  transactions
contemplated  hereby have been duly and validly adopted and approved by at least
a  majority  of the Board of  Directors  of NBT Bank and BSB Bank,  and the sole
shareholder of each of the Merging Banks.

2.8  OFFICES OF THE RESULTING BANK
                  NBT Bank,  as the  Resulting  Bank,  shall  relocate  its main
office to  Binghamton,  New York,  and shall  establish  a branch  office at its
former main  office  location  and also shall  establish  as branch  offices the
principal office and branch offices of BSB Bank (except the facility, if any, of
BSB that  becomes the main office of the  Resulting  Bank).  The location of the
main  office and other  offices of the  Resulting  Bank shall be as set forth at
ANNEX 2 hereto.

                                    ARTICLE 3
                                  MISCELLANEOUS
3.1  SUCCESSORS
                  This Plan of Merger shall be binding on the  successors of NBT
Bank and BSB Bank.

3.2  COUNTERPARTS
                           This  Plan  of  Merger   may  be   executed   in  two
                           counterparts,  each  of  which  shall  be  deemed  an
                           original,  but which taken together shall  constitute
                           one and the same document.

                                                [SIGNATURE PAGE FOLLOWS]





                  IN WITNESS  WHEREOF,  each of the parties has caused this Plan
of  Merger  to be duly  executed  on its  behalf by an  officer  thereunto  duly
authorized, all as of the day and year first above written.


                                                 NBT BANK, NATIONAL ASSOCIATION



ATTEST:


      By:                                      By:
             ------------------------                 ----------------------
      Name:  John D. Roberts                   Name:  Daryl R. Forsythe
      Title: Senior Vice President and         Title: Chairman and Chief
             Corporate Secretary                      Executive Officer



                            BSB BANK & TRUST COMPANY



ATTEST:

      By:                                      By:
             ------------------------                 -------------------------
      Name:  Larry G. Denniston                Name:  Thomas L. Thorn
      Title: Executive Vice President          Title: Acting President and Chief
             and Secretary                            Chief Executive Officer




                                    ANNEX 1

         DIRECTORS AND OFFICERS OF RESULTING BANK AFTER THE BANK MERGER



                                     ANNEX 2

                 OFFICES OF RESULTING BANK AFTER THE BANK MERGER

                  At the Effective  Time of the Bank Merger,  NBT Bank will have
the following offices:

LOCATION OF MAIN OFFICE



LOCATION OF BRANCH OFFICES



                                  EXHIBIT 27.1
                Financial Data Schedule for the six months ended
                                  June 30, 2000