EXHIBIT 10.4





                                                     January 25, 2005


Terra Nova Acquisition Corporation
2 Bloor Street West
Suite 3400
Toronto, Ontario, Canada M4W 3E2

EarlyBirdCapital, Inc.
275 Madison Avenue
Suite 1203
New York, New York 10016

         Re: Initial Public Offering

Gentlemen:

         The undersigned director and stockholder of Terra Nova Acquisition
Corporation ("Company"), in consideration of EarlyBirdCapital, Inc. ("EBC")
entering into a letter of intent ("Letter of Intent") to underwrite an initial
public offering of the securities of the Company ("IPO") and embarking on the
IPO process, hereby agrees as follows (certain capitalized terms used herein are
defined in paragraph 11 hereof):

         1. If the Company solicits approval of its stockholders of a Business
Combination, the undersigned will vote all Insider Shares owned by him in
accordance with the majority of the votes cast by the holders of the IPO Shares.

         2. In the event that the Company fails to consummate a Business
Combination within 18 months from the effective date ("Effective Date") of the
registration statement relating to the IPO (or 24 months under the circumstances
described in the prospectus relating to the IPO), the undersigned will take all
reasonable actions within his power to cause the Company to liquidate as soon as
reasonably practicable. The undersigned hereby waives any and all right, title,
interest or claim of any kind in or to any distribution of the Trust Fund (as
defined in the Letter of Intent) as a result of such liquidation with respect to
the undersigned's Insider Shares ("Claim") and hereby waives any Claim the
undersigned may have in the future as a result of, or arising out of, any
contracts or agreements with the Company and will not seek recourse against


Terra Nova Acquisition Corporation
EarlyBirdCapital, Inc.
January 25, 2005
Page 2


the Trust Fund for any reason whatsoever.

         3. In order to minimize potential conflicts of interest which may arise
from multiple affiliations, the undersigned agrees to present to the Company for
its consideration, prior to presentation to any other person or entity, any
suitable opportunity to acquire an operating business, until the earlier of the
consummation by the Company of a Business Combination, the liquidation of the
Company or until such time as the undersigned ceases to be an officer or
director of the Company, subject to any pre-existing fiduciary obligations the
undersigned might have.

         4. The undersigned acknowledges and agrees that the Company will not
consummate any Business Combination which involves a company which is affiliated
with any of the Insiders unless the Company obtains an opinion from an
independent investment banking firm reasonably acceptable to EBC that the
business combination is fair to the Company's stockholders from a financial
perspective.

         5. Neither the undersigned, any member of the family of the
undersigned, nor any Affiliate of the undersigned will be entitled to receive
and will not accept any compensation for services rendered to the Company prior
to the consummation of the Business Combination; provided that the undersigned
shall be entitled to reimbursement from the Company for their out-of-pocket
expenses incurred in connection with seeking and consummating a Business
Combination.

         6. Neither the undersigned, any member of the family of the
undersigned, or any Affiliate of the undersigned will be entitled to receive or
accept a finder's fee or any other compensation in the event the undersigned,
any member of the family of the undersigned or any Affiliate of the undersigned
originates a Business Combination.

         7. The undersigned will escrow his Insider Shares for the three year
period commencing on the Effective Date subject to the terms of a Stock Escrow
Agreement which the Company will enter into with the undersigned and an escrow
agent acceptable to the Company.

         8. The undersigned agrees to be a director of the Company until the
earlier of the consummation by the Company of a Business Combination or the
liquidation of the Company. The undersigned's biographical information furnished
to the Company and EBC and attached hereto as Exhibit A is true and accurate in
all respects, does not omit any material information with respect to the
undersigned's background and contains all of the information required to be
disclosed pursuant to Section 401 of


Terra Nova Acquisition Corporation
EarlyBirdCapital, Inc.
January 25, 2005
Page 3


Regulation S-K, promulgated under the Securities Act of 1933. The undersigned's
Questionnaire furnished to the Company and EBC and annexed as Exhibit B hereto
is true and accurate in all respects. The undersigned represents and warrants
that:

    (a) he is not subject to or a respondent in any legal action for, any
injunction, cease-and-desist order or order or stipulation to desist or refrain
from any act or practice relating to the offering of securities in any
jurisdiction;

    (b) he has never been convicted of or pleaded guilty to any crime (i)
involving any fraud or (ii) relating to any financial transaction or handling of
funds of another person, or (iii) pertaining to any dealings in any securities
and he is not currently a defendant in any such criminal proceeding; and

    (c) he has never been suspended or expelled from membership in any
securities or commodities exchange or association or had a securities or
commodities license or registration denied, suspended or revoked.

         9. The undersigned has full right and power, without violating any
agreement by which he is bound, to enter into this letter agreement and to serve
as a director of the Company.

         10. The undersigned authorizes any employer, financial institution, or
consumer credit reporting agency to release to EBC and its legal representatives
or agents (including any investigative search firm retained by EBC) any
information they may have about the undersigned's background and finances
("Information"). Neither EBC nor its agents shall be violating the undersigned's
right of privacy in any manner in requesting and obtaining the Information and
the undersigned hereby releases them from liability for any damage whatsoever in
that connection.

         11. As used herein, (i) a "Business Combination" shall mean an
acquisition by merger, capital stock exchange, asset or stock acquisition,
reorganization or otherwise, of an operating business selected by the Company;
(ii) "Insiders" shall mean all officers, directors and stockholders of the
Company immediately prior to the IPO; (iii) "Insider Shares" shall mean all of
the shares of Common Stock of the Company owned by an Insider prior to the IPO;
and (iv) "IPO Shares" shall mean the shares of Common Stock issued in the
Company's IPO.



Terra Nova Acquisition Corporation
EarlyBirdCapital, Inc.
January 25, 2005
Page 4





                                                     Brendan Calder
                                                     --------------
                                                     Print Name of Insider


                                                     /s/ Brendan Calder
                                                     ------------------
                                                     Signature





EXHIBIT A

         Brendan Calder has been a member of our board of directors since our
inception. Since January 2001, Mr. Calder has been an adjunct professor of
strategic management at the Rotman School of Management of the University of
Toronto. From January 1996 until March 2000, Mr. Calder was the chairman of the
board, president and chief executive officer of CIBC Mortgages in Toronto
Ontario. He was also president and a director of Firstline Trust Company from
April 1988 to January 1996. Mr. Calder holds a Bachelor of Mathematics degree
from the University of Waterloo.