Certificate Number C-I                                     310 Common Securities

         THIS COMMON SECURITY HAS NOT BEEN REGISTERED  UNDER  THE SECURITIES ACT
OF  1933,  AS  AMENDED,  AND MAY NOT BE  OFFERED,  SOLD,  PLEDGED  OR  OTHERWISE
TRANSFERRED EXCEPT PURSUANT TO AN EXEMPTION FROM REGISTRATION.

          THIS CERTIFICATE IS NOT TRANSFERABLE EXCEPT IN COMPLIANCE WITH SECTION
8.1 OF THE DECLARATION.

                                  June 26, 2002
                 Certificate Evidencing Floating Rate Securities

                                     [COPY]

                           North Bay Statutory Trust I

          North Bay Statutory  Trust I, a statutory trust created under the laws
of the State of  Connecticut  (the  "Trust"),  hereby  certifies  that North Bay
Bancorp (the "Holder") is the registered owner of common securities of the Trust
representing  undivided  beneficial  interests  in the  assets of the Trust (the
"Common  Securities").  The  designation,   rights,  privileges,   restrictions,
preferences and other terms and provisions of the Common Securities  represented
hereby are issued  pursuant  to, and shall in all  respects  be subject  to, the
provisions of the Amended and Restated  Declaration  of Trust of the Trust dated
as of June 26, 2002, among Terry L. Robinson,  Dale Brain and Lee-Ann Cimino, as
Administrators,  State Street Bank and Trust  Company of  Connecticut,  National
Association,  as Institutional  Trustee,  North Bay Bancorp, as Sponsor, and the
holders from time to time of undivided  beneficial interest in the assets of the
Trust  including the  designation  of the terms of the Common  Securities as set
forth in Annex I to such  amended and restated  declaration,  as the same may be
amended from time to time (the "Declaration"). Capitalized terms used herein but
not defined shall have the meaning given them in the Declaration.  The Holder is
entitled to the benefits of the Guarantee to the extent  provided  therein.  The
Sponsor will provide a copy of the Declaration,  the Guarantee and the Indenture
to the  Holder  without  charge  upon  written  request  to the  Sponsor  at its
principal place of business.

          As set  forth  in the  Declaration,  where an  Event  of  Default  has
occurred  and is  continuing,  the  rights of Holders  of Common  Securities  to
payment in respect of Distributions and payments upon Liquidation, redemption or
otherwise  are  subordinated  to the rights of payment of Holders of the Capital
Securities.

          Upon  receipt  of  this  Certificate,  the  Holder  is  bound  by  the
Declaration and is entitled to the benefits thereunder.

          By acceptance  of this  Certificate,  the Holder agrees to treat,  for
United States federal income tax purposes,  the Debentures as  indebtedness  and
the Common  Securities  as evidence of  undivided  beneficial  ownership  in the
Debentures.

          This Common Security is governed by, and construed in accordance with,
the laws of the State of  Connecticut,  without regard to principles of conflict
of laws.

                     Signature appears on the following page


<PAGE>

         IN WITNESS WHEREOF, the Trust has duly executed this certificate.

                                          NORTH BAY STATUTORY TRUST I


                                          By:   /s/ Terry L. Robinson
                                             -----------------------------------
                                              Name: Robinson
                                              Title: Administrator


                                                      [COPY]
<PAGE>

                           REVERSE OP COMMON SECURITY

          Distributions  payable on each Common  Security  will be  identical in
amount to the  Distributions  payable on each Capital  Security,  which is at an
annual rate equal to 5.3369%  beginning on (and  including) the date of original
issuance and ending on (but excluding)  September 26, 2002 and at an annual rate
for each successive period beginning on (and including)  September 26, 2002, and
each  succeeding  Distribution  Payment Date, and ending on (but  excluding) the
next succeeding Distribution Payment Date (each a "Distribution Period"),  equal
to 3-Month LIBOR, determined as described below, plus 3.45% (the "Coupon Rate");
provided, however, that prior to June 26, 2007, the Coupon Rate shall not exceed
11.95%,  applied  to the  stated  liquidation  amount of  $l,000.00  per  Common
Security,  such rate being the rate of  interest  payable on the  Debentures  to
be held by the Institutional Trustee. Distributions in arrears for more than one
quarterly period will bear interest thereon  compounded at the Distribution Rate
(to the extent  permitted by applicable law). The term  "Distributions"  as used
herein includes payments of Interest and any principal on the Debentures held by
the  Institutional  Trustee unless  otherwise  stated. A Distribution is payable
only to the extent that payments are made in respect of the  Debentures  held by
the Institutional  Trustee and to the extent the Institutional Trustee has funds
available therefor. As used herein,  "Determination Date" means the date that is
two London  Banking Days (i.e.,  a business day in which dealings in deposits in
U.S.  dollars are  transacted  in the London  interbank  market)  preceding  the
commencement of the relevant  Distribution Period. In the event that any date on
which a Distribution  is payable on this Common  Security is not a Business Day,
then a payment of the Distribution payable on such date will be made on the next
succeeding  day which is a Business Day (and without any  Distribution  or other
payment in respect of any such delay),  except that,  if such Business Day is in
the next succeeding calendar year, such payment shall be made on the immediately
preceding  Business  Day, in each case with the same force and effect as if made
on the date the payment was originally  payable.  The amount of interest payable
for the Distribution  Period  commencing  September 26, 2002 and each succeeding
Distribution  Period  will be  calculated  by  applying  the Coupon  Rate to the
principal amount outstanding at the commencement of the Distribution  Period and
multiplying  each such amount by the actual  number of days in the  Distribution
Period concerned divided by 360.


         "3-Month  LIBOR" as used  herein,  means the London  interbank  offered
interest rate for three-month  U.S. dollar deposits  determined by the Debenture
Trustee  in the  following  order  of  priority:  (i) the rate  (expressed  as a
percentage per annum) for U.S.  dollar  deposits  having a three-month  maturity
that appears on Telerate Page 3750 as of 11:00 am.  (London time) on the related
Determination  Date ("Telerate Page 3750" means the display  designated as "Page
3750" on the Dow Jones  Telerate  Service or such other page as may replace Page
3750 on that  service or such other  service or services as may be  nominated by
the British  Bankers'  Association as the information  vendor for the purpose of
displaying  London interbank  offered rates for U.S. dollar  deposits);  (ii) if
such rate cannot be identified on the related  Determination Date, the Debenture
Trustee will request the principal  London  offices of four leading banks in the
London interbank market to provide such banks' offered quotations  (expressed as
percentages  per annum) to prime banks in the London  interbank  market for U.S.
dollar deposits having a three-month  maturity as of 11:00 a.m. (London time) on
such Determination Date. If at least two quotations are provided,  3-Month LIBOR
will be the  arithmetic  mean of such  quotations;  (iii) if fewer than two such
quotations are provided as requested in clause (ii) above, the Debenture Trustee
will  request  four  major New York City banks to provide  such  banks'  offered
quotations  (expressed as percentages  per annum) to leading  European banks for
loans in U.S. dollars as of 11:00 a.m. (London time) on such Determination Date.
If at  least  two  such  quotations  are  provided,  3-Month  LIBOR  will be the
arithmetic mean of such  quotations;  and (iv) if fewer than two such quotations
are  provided as  requested  in clause  (iii)  above,  3-Month  LI.BOR will be a
3-Month LIBOR  determined with respect to the  Distribution  Period  immediately
preceding such current Distribution Period. If the rate for U.S. dollar deposits
having a three-month maturity that initially appears on Telerate Page 3750 as of
11:00 a.m. (London time) on the related  Determination Date is superseded on the
Telerate  Page 3750 by a  corrected  rate by 12:00  noon  (London  time) on such
Determination  Date, then the corrected rate as so substituted on the applicable
page will be the applicable 3-Month LIBOR for such Determination Date.


         The Coupon Rate for any  Distribution  Period will at no time be higher
than the maximum rate then permitted by New York law as the same may be modified
by United States law.


         All  percentages   resulting  from  any   calculations  on  the  Common
Securities will be rounded, if necessary,  to the nearest one hundred-thousandth
of a percentage  point,  with five  one-millionths of a percentage point rounded
upward (e.g.,  9.876545% or .09876545 being rounded to 9.87655% or .0987655, and
all dollar amounts used in or resulting from such calculation will be rounded to
the nearest cent (with one-half cent being rounded upward)).


         Except  as  otherwise  described  below,  Distributions  on the  Common
Securities  will be cumulative,  will accrue from the date of original  issuance
and will be payable  quarterly in arrears on March 26, June 26, September 26 and
December 26 of each year, commencing on September 26, 2002. The Debenture Issuer
has the  right  under  the  Indenture  to  defer  payments  of  interest  on the
Debentures by extending  the interest  payment  period for up to 20  consecutive
quarterly periods (each an "Extension Period") on the Debentures, subject to the
conditions  described below,  although such interest would continue to accrue on
the  Debentures  at an annual  rate equal to the  Distribution  Rate  compounded
quarterly  to the  extent  permitted  by law  during any  Extension  Period.  No
Extension  Period may end on a date other than an Interest  Payment Date. At the
end of any such Extension Period the Sponsor shall pay all interest then accrued
and  unpaid on the  Debentures  (together  with  Additional  Interest  thereon);
provided, however, that no Extension Period may extend beyond the Maturity Date.
Prior to the termination of any Extension Period, the Sponsor may further extend
such  period,  provided  that such period  together  with all such  previous and
further consecutive extensions thereof shall not exceed 20 consecutive quarterly
periods,  or extend  beyond  the  Maturity  Date.  Upon the  termination  of any
Extension  Period and upon the payment of all accrued  and unpaid  interest  and
Additional Interest, the Sponsor may commence a new Extension Period, subject to
the foregoing requirements.  No interest or Additional Interest shall be due and
payable  during  an  Extension  Period,  except  at the end  thereof,  but  each
installment  of interest that would  otherwise  have been due and payable during
such Extension  Period shall bear  Additional  Interest.  If  Distributions  are
deferred,  the  Distributions  due  shall be paid on the date  that the  related
Extension Period terminates,  to Holders of the Securities as they appear on the
books and records of the Trust on the record  date  immediately  preceding  such
date.  Distributions  on the Securities must be paid on the dates payable (after
giving  effect to any  Extension  Period) to the extent that the Trust has funds
available for the payment of such  distributions  in the Property Account of the
Trust.  The  Trust's  funds  available  for  Distribution  to the Holders of the
Securities will be limited to payments received from the Debenture  Issuer.  The
payment of  Distributions  out of moneys held by the Trust is  guaranteed by the
Guarantor pursuant to the Guarantee.


         The  Common   Securities   shall  be  redeemable  as  provided  in  the
Declaration.


<PAGE>

                                   ASSIGNMENT

FOR VALUE RECEIVED,  the undersigned  assigns and transfers this Common Security
Certificate to:


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(Insert assignee's social security or tax identification number)________________


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(Insert address and zip code of assignee) and irrevocably appoints



                              ________________________________________  agent to
                              transfer this Common  Security  Certificate on the
                              books  of the  Trust.  The  agent  may  substitute
                              another to act for him or her.

                              Date:_____________________________________________

                              Signature:________________________________________

                              (Sign  exactly  as your name  appears on the other
                              side of this Common Security Certificate)


                              Signature:________________________________________

                              (Sign  exactly  as your name  appears on the other
                              side of this common Security Certificate)

        Signature Guarantee (1)


------------------------
1 Signature must be guaranteed by an "eligible guarantor  institution" that is a
bank,  stockbroker,  savings and loan  association or credit union,  meeting the
requirements of the Security registrar, which requirements include membership or
participation in the Securities  Transfer Agents Medallion  Program ("STAMP") or
such other  "signature  guarantee  program" as may be determined by the Security
registrar in addition to, or in substitution  for, STAMP, all in accordance with
the Securities Exchange Act of 1934, as amended.