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As filed with the Securities and Exchange
    Commission on July 20, 2011.
 
 
 Registration
    No. 333-174843
 
 
  UNITED STATES SECURITIES AND
    EXCHANGE COMMISSION
 Washington, D.C.
    20549
   
  AMENDMENT NO. 1
 
 
 TO
 
 
 Form S-4
 
 REGISTRATION
    STATEMENT
 UNDER
 THE SECURITIES ACT OF
    1933
    Dawson Geophysical
    Company
 (Exact name of registrant as
    specified in its charter)
  Texas

1382

75-0970548(State or other jurisdiction
    of
    incorporation or organization)

(Primary Standard Industrial
    Classification Code Number)

(I.R.S. Employer
    Identification Number)      508 West Wall, Suite 800
 Midland, Texas 79701
 (432) 684-3000
 (Address, including zip code,
    and telephone number, including area code, of registrants
    principal executive offices)
     Stephen C. Jumper
 President and Chief Executive Officer
 Dawson Geophysical Company
 508 West Wall, Suite 800
 Midland, Texas 79701
 (432) 684-3000
 (Name, address, including zip
    code, and telephone number, including area code, of agent for
    service)
      Copies to:
  Neel Lemon
    Sarah Rechter
    Baker Botts L.L.P.
    2001 Ross Avenue
    Dallas, Texas 75201
    (214) 953-6500

Wayne A. Whitener
    President and Chief Executive Officer
    TGC Industries, Inc.
    101 E. Park Blvd., Suite 955
    Plano, Texas 75074
    (972) 881-1099

Rice M. Tilley, Jr.
    Bruce Newsome
    Haynes and Boone, LLP
    2323 Victory Avenue, Suite 700
    Dallas, Texas 75219
    (214) 651-5000       Approximate date of commencement of the proposed sale of the
    securities to the public:
  o
  o
  o
  12b-2
  Large
    accelerated
    filer o
    Accelerated
    filer þ
    Non-accelerated
    filer o
    Smaller
    reporting
    company o     o
  o
  The Registrant hereby amends this Registration Statement on
    such date or dates as may be necessary to delay its effective
    date until the Registrant shall file a further amendment which
    specifically states that this Registration Statement shall
    thereafter become effective in accordance with Section 8(a)
    of the Securities Act of 1933, as amended, or until this
    Registration Statement shall become effective on such date as
    the Securities and Exchange Commission, acting pursuant to
    Section 8(a), may determine.




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The
information in this joint proxy statement/prospectus is not
complete and may be changed. We may not sell these securities
until the registration statement filed with the Securities and
Exchange Commission is effective. This preliminary joint proxy
statement/prospectus is not an offer to sell these securities
and we are not soliciting an offer to buy these securities in
any state where the offer or sale is not permitted.


SUBJECT TO COMPLETION, DATED
    JULY 20, 2011
 
  PROPOSED MERGER  YOUR VOTE IS VERY IMPORTANT
   COMPANY LOGO

COMPANY LOGO                     
    the holders of at least a majority of the outstanding shares of
    Dawson common stock present in person or represented by proxy
    and entitled to vote at the Dawson special meeting, assuming a
    quorum is present, approve the issuance of shares of Dawson
    common stock in connection with the proposed merger; and
    the merger agreement is approved by the holders of at least 80%
    of the outstanding shares of TGC common stock.  Your vote is very
    important, regardless of the number of shares you own.
    For a discussion of certain significant matters that you
    should consider before voting, see Risk
    Factors beginning on page 24.
    Sincerely,
    Stephen C. JumperPresident and Chief Executive OfficerDawson Geophysical Company

Sincerely,
    Wayne A. WhitenerPresident and Chief Executive OfficerTGC Industries, Inc.   Neither the Securities and Exchange Commission nor any state
    securities commission has approved or disapproved of the Dawson
    common stock to be issued pursuant to the merger or passed upon
    the adequacy or accuracy of this joint proxy
    statement/prospectus. Any representation to the contrary is a
    criminal offense.




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ADDITIONAL
    INFORMATION
  http://www.sec.gov
  Dawson Geophysical Company508 West Wall, Suite 800
    Midland, Texas 79701
    Telephone: (432) 684-3000

TGC Industries, Inc.101 East Park Blvd., Suite 955
    Plano, Texas 75074
    Telephone: (972) 881-1099or

orMorrow & Co., LLC470 West Avenue, 3rd Floor
    Stamford, CT 06902
    Banks and brokers call collect: (203) 658-9400
    Shareholders Please Call Toll Free: (800)
    607-0088

D.F. King & Co., Inc.48 Wall Street, 22nd Floor
    New York, New York 10005
    Banks and brokers call collect: (212) 269-5550
    Others call toll-free: (800) 967-4617   You will not be charged for any of the documents that you
    request. Shareholders requesting documents should do so by
    [  ], 2011, in order to receive them before the
    applicable special meeting.
 
   
  This document does not constitute an offer to sell, or a
    solicitation of an offer to buy, any securities, or the
    solicitation of a proxy, in any jurisdiction to or from any
    person to whom it is unlawful to make any such offer or
    solicitation in such jurisdiction. Information contained in this
    document regarding Dawson has been provided by Dawson and
    information contained in this document regarding TGC has been
    provided by TGC.
  VOTING BY
    TELEPHONE, INTERNET OR MAIL
  Shareholders
    of record of either Dawson or TGC may submit their proxies
    by:
  Telephone. (800) 690-6903
  Internet. http://www.proxyvote.com
  Mail.
  If you
    hold your shares through a bank, broker, custodian or other
    record holder:




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DAWSON
    GEOPHYSICAL COMPANY508 West Wall,
    Suite 800
    Midland, TX 79701432-684-3000
  NOTICE OF SPECIAL MEETING OF
    SHAREHOLDERS
 TO BE HELD ON
    [  ], 2011
      
    to approve the issuance of shares of Dawson common stock to TGC
    shareholders pursuant to the terms of the Agreement and Plan of
    Merger, dated March 20, 2011, by and among Dawson, TGC
    Industries, Inc., or TGC, and 6446 Acquisition Corp., a wholly
    owned subsidiary of Dawson; and
    to approve adjournments of the special meeting, if necessary or
    appropriate, to permit the solicitation of additional proxies if
    there are not sufficient votes at the time of the special
    meeting to adopt the foregoing proposal.        Dawsons board of directors recommends that Dawson
    shareholders vote FOR approval of the issuance of
    shares of Dawson common stock to TGC shareholders pursuant to
    the merger agreement and FOR any adjournment of the
    Dawson special meeting, if necessary or appropriate, to permit
    further solicitation of proxies.
     Secretary
      IMPORTANT
  Remember, your vote is important, so
    please act today!




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TGC
    INDUSTRIES, INC.101 E. Park Blvd.,
    Suite 955
    Plano, Texas 75074(972) 881-1099
  NOTICE OF SPECIAL MEETING OF
    SHAREHOLDERS
 TO BE HELD ON
    [  ], 2011
      
    to approve the Agreement and Plan of Merger, dated
    March 20, 2011, by and among TGC, Dawson Geophysical
    Company, or Dawson, and 6446 Acquisition Corp., a wholly owned
    subsidiary of Dawson;
    to approve a non-binding advisory resolution on certain
    compensation to be paid by TGC to TGCs named executive
    officers upon consummation of the merger; and
    to approve adjournments of the special meeting, if necessary or
    appropriate, to permit the solicitation of additional proxies if
    there are not sufficient votes at the time of the special
    meeting to approve the merger agreement.       
  TGCs board of directors recommends that TGC
    shareholders vote FOR approval of the merger
    agreement, FOR approval of the non-binding advisory
    resolution on certain compensation to be paid by TGC to
    TGCs named executive officers upon consummation of the
    merger and FOR adjournments of the TGC special
    meeting, if necessary or appropriate, to permit further
    solicitation of proxies. In considering the recommendations of
    the TGC board of directors, TGC shareholders should be aware
    that members of TGCs board of directors and its executive
    officers have agreements and arrangements that provide them with
    interests in the merger that are different from, or in addition
    to, those of TGC shareholders. See The Merger 
    Conflicts of Interests beginning on page 89.
 
     Secretary
      IMPORTANT
  Remember, your vote is important,
    so please act today!




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TABLE OF
    CONTENTS
   
 
 PageQUESTIONS AND ANSWERS ABOUT THE MERGER


vSUMMARY


1The Parties to the Merger Agreement


1The Merger


1Recommendations of the Dawson Board of
    Directors


3Recommendations of the TGC Board of Directors


3Opinion of Raymond James & Associates,
    Inc., Financial Advisor to Dawson


3Opinion of Southwest Securities, Inc., Financial
    Advisor to TGC


4Ownership of Dawson Following the Merger


4Board of Directors and Management of Dawson
    Following the Merger


4The Dawson Special Meeting


5The TGC Special Meeting


5Record Date


5Votes Required to Approve the Proposals


5Outstanding Shares and Share Ownership of
    Management


6Conditions to Completion of the Merger


6Regulatory Requirements


7Termination of the Merger Agreement


8Termination Fee and Expense Reimbursement


8Conflicts of Interests


9Acquisition Proposals


10Risk Factors


11Material U.S. Federal Income Tax Consequences of
    the Merger


11Accounting Treatment


11Listing of Dawson Common Stock and Delisting and
    Deregistration of TGC Common Stock


12Appraisal Rights


12Comparison of Shareholder Rights


12FINANCIAL SUMMARY


13Selected Historical Financial Data of Dawson


13Selected Historical Consolidated Financial Data
    of TGC


15Selected Unaudited Pro Forma Condensed Combined
    Consolidated Financial and Other Information


17COMPARATIVE PER SHARE MARKET PRICE AND DIVIDEND
    INFORMATION


19Dawson Historical Market Price Data and
    Dividends


19TGC Historical Market Price Data and Dividends


20Value of Merger Consideration


20Comparative Per Share Information


21UNAUDITED COMPARATIVE PER SHARE DATA


22RISK FACTORS


24CAUTIONARY STATEMENTS CONCERNING FORWARD-LOOKING
    STATEMENTS


32THE DAWSON SPECIAL MEETING


34Date, Time and Place


34Purpose


34Board Recommendations


34




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PageRecord Date; Outstanding Shares;
    Shares Entitled to Vote


34Quorum


34Required Vote


35Tabulation of the Votes


35Stock Ownership of and Voting by Dawsons
    Directors and Executive Officers


35Voting of Shares by Holders of Record


35Voting of Shares Held in Street Name


36Revocability of Proxies; Changing Your Vote


37Solicitation of Proxies


37No Other Business


37Adjournments and Postponements


37Assistance


38DAWSON PROPOSAL 1  APPROVAL OF
    THE ISSUANCE OF SHARES OF DAWSON COMMON STOCK TO TGC
    SHAREHOLDERS PURSUANT TO THE MERGER AGREEMENT


39DAWSON PROPOSAL 2  ADJOURNMENT OF
    THE DAWSON SPECIAL MEETING


40THE TGC SPECIAL MEETING


41Date, Time and Place


41Purpose


41Board Recommendations


41Record Date; Outstanding Shares;
    Shares Entitled to Vote


41Quorum


41Required Vote


42Tabulation of the Votes


42Stock Ownership of and Voting by TGCs
    Directors and Executive Officers


42Voting of Shares by Holders of Record


42Voting of Shares Held in Street Name


43Revocability of Proxies; Changing Your Vote


44Solicitation of Proxies


44No Other Business


44Adjournments and Postponements


45Assistance


45TGC PROPOSAL 1  APPROVAL OF THE
    MERGER AGREEMENT


46TGC PROPOSAL 2  NON-BINDING,
    ADVISORY VOTE ON APPROVAL OF CERTAIN COMPENSATION TO BE PAID BY
    TGC TO TGCS NAMED EXECUTIVE OFFICERS


47TGC PROPOSAL 3  ADJOURNMENT OF
    THE TGC SPECIAL MEETING


49THE PARTIES TO THE MERGER


50THE MERGER


52Overview


52Background of the Merger


52Dawsons Reasons for the Merger and
    Recommendation of Dawsons Board of Directors


60TGCs Reasons for the Merger and
    Recommendation of TGCs Board of Directors


65Certain Information Provided by the Parties


68Opinion of Dawsons Financial Advisor


72Opinion of TGCs Financial Advisor


78Stock Ownership of Directors and Executive
    Officers of Dawson and TGC


86 
 ii




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PageMerger Consideration


87Accounting Treatment


88Listing of Dawson Common Stock and Delisting and
    Deregistration of TGC Common Stock


88Restrictions on Sales of Shares of Dawson Common
    Stock Received in the Merger


89Opinions as to Material U.S. Federal Income Tax
    Consequences of the Merger


89Ownership of Dawson Following the Merger


89Board of Directors and Management of Dawson
    Following the Merger


89Conflicts of Interests


89Appraisal Rights


94Regulatory Requirements


94Dividend Policy


95THE MERGER AGREEMENT


96Merger


96Effective Time; Closing


96Governance Matters


97Merger Consideration


97Effect of the Merger on TGCs Equity
    Awards


98Payment of Merger Consideration


98Representations and Warranties


100Definition of Material Adverse
    Effect


102Covenants and Agreements


102Conditions to Completion of the Merger


110Termination of the Merger Agreement


112Termination Fee and Expense Reimbursement


113Amendments, Extensions and Waivers


115Specific Performance


116Governing Law


116THE TGC SHAREHOLDER VOTING AGREEMENTS


117No Disposition


117Voting of Shares of TGC Common Stock


117Irrevocable Proxy


117Termination of the TGC Shareholder Voting
    Agreements


118Shareholder Capacity


118Specific Performance


118Governing Law


118THE DAWSON SHAREHOLDER VOTING AGREEMENT


119No Disposition


119Voting of Shares of Dawson Common Stock


119Irrevocable Proxy


119Termination of the Dawson Shareholder Voting
    Agreement


120Shareholder Capacity


120Specific Performance


120Governing Law


120THE EMPLOYMENT AGREEMENTS


121 
 iii




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PageTerm


121Duties and Compensation


121Termination of the Employment Agreements


121Payment upon Termination


123Restrictive Covenants


123Governing Law


124Description of Specific Employment Agreements


124MATERIAL U.S. FEDERAL INCOME TAX CONSEQUENCES OF
    THE MERGER


125General


125Qualification of the Merger as a Reorganization
    and Tax Opinions


126Material U.S. Federal Income Tax Consequences if
    the Merger Qualifies as a Tax-Free Reorganization


126Material U.S. Federal Income Tax Consequences if
    the Merger Fails to Qualify as a Tax-Free Reorganization


127Backup Withholding and Information Reporting


127Reporting Requirements


127COMPARISON OF SHAREHOLDER RIGHTS


128EXPERTS


133UNAUDITED PRO FORMA CONDENSED COMBINED
    CONSOLIDATED FINANCIAL INFORMATION


134LEGAL MATTERS


146DATES FOR SUBMISSION OF SHAREHOLDER
    PROPOSALS FOR THE 2011 ANNUAL MEETINGS


147Dawson


147TGC


147HOUSEHOLDING OF JOINT PROXY
    STATEMENT/PROSPECTUS


149WHERE YOU CAN FIND MORE INFORMATION


150LIST OF ANNEXESAnnex A  Agreement and Plan of
    Merger


A-1Annex B  Opinion of Raymond
    James & Associates, Inc.


B-1Annex C  Opinion of Southwest
    Securities, Inc.


C-1Annex D  Form of TGC Shareholder
    Voting Agreement


D-1Annex E  Form of Dawson
    Shareholder Voting Agreement


E-1Annex F  Form of Employment
    Agreement


F-1Annex G  Form of Indemnification
    Agreement


G-1EX-5.1EX-8.1EX-8.2EX-23.4EX-23.5EX-99.3EX-99.4EX-99.6EX-99.7  
  iv




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QUESTIONS
    AND ANSWERS ABOUT THE MERGER  The following are brief answers to common questions that you
    may have regarding the proposals being considered at the special
    meeting of Dawson shareholders, which we refer to as the Dawson
    special meeting, and the special meeting of TGC shareholders,
    which we refer to as the TGC special meeting. Dawson and TGC
    urge you to read carefully this entire joint proxy
    statement/prospectus because the information in this section may
    not provide all the information that might be important to you
    in determining how to vote. Additional important information is
    also contained in the annexes to, and the documents incorporated
    by reference in, this joint proxy statement/prospectus. See
    Where You Can Find More Information beginning on
    page 150.
 
    Q:
    
    Why am I receiving this document?A:
    
    You are receiving this joint proxy statement/prospectus because
    you are a shareholder of record of either Dawson or TGC as of
    [  ], 2011, the record date for the special
    meetings.Dawson has agreed to acquire TGC by means of a merger of Merger
    Sub with and into TGC, with TGC surviving the merger as a wholly
    owned subsidiary of Dawson.In order to complete the merger, among other conditions, Dawson
    shareholders must vote to approve the issuance of shares of
    Dawson common stock to TGC shareholders pursuant to the merger
    agreement. In addition, TGC shareholders must vote to approve
    the merger agreement. Dawson and TGC will hold separate special
    meetings to obtain these approvals.At the TGC special meeting, TGC shareholders will also be voting
    on a non-binding advisory resolution on certain compensation to
    be paid by TGC to TGCs named executive officers upon
    consummation of the merger. However, approval by TGC
    shareholders of such compensation is not a condition to the
    merger. Accordingly, even if TGC shareholders do not approve
    such compensation, if all closing conditions to the merger are
    satisfied, Dawson and TGC will be obligated to close the merger,
    and TGCs named executive officers will be paid such
    compensation.This joint proxy statement/prospectus, which you should read
    carefully, contains important information about the merger, the
    merger agreement and the special meetings of Dawson and TGC
    shareholders. Dawson and TGC are each delivering this document
    to their shareholders because it is a proxy statement being used
    by the board of directors of each of Dawson and TGC to solicit
    proxies of shareholders in connection with their respective
    special meetings. In addition, this document is a prospectus
    being delivered to TGC shareholders because Dawson is offering
    shares of its common stock to TGC shareholders in exchange for
    their shares of TGC common stock in connection with the proposed
    merger.Q:
    
    What will happen in the merger?A:
    
    In the merger, Merger Sub will be merged with and into TGC, with
    TGC surviving as a direct wholly owned subsidiary of Dawson.
    After the merger, the current shareholders of Dawson and the
    current shareholders of TGC will be the shareholders of Dawson.Q:
    
    What are holders of Dawson common stock being asked to vote
    on?A:
    
    Holders of Dawson common stock are being asked to: approve the issuance of shares of Dawson common
    stock to TGC shareholders pursuant to the terms of the merger
    agreement; and v




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 approve adjournments of the Dawson special meeting,
    if necessary or appropriate, to permit the solicitation of
    additional proxies if there are insufficient votes at the time
    of the Dawson special meeting to adopt the foregoing proposal.Q:
    
    What are holders of TGC common stock being asked to vote
    on?A:
    
    Holders of TGC common stock are being asked to: approve the merger agreement; approve the non-binding advisory resolution on
    certain compensation to be paid by TGC to TGCs named
    executive officers upon consummation of the merger; and approve adjournments of the TGC special meeting, if
    necessary or appropriate, to permit the solicitation of
    additional proxies if there are insufficient votes at the time
    of the TGC special meeting to approve the merger agreement.Q:
    
    Why have Dawson and TGC decided to merge?A:
    
    Dawson and TGC believe that the merger will provide strategic
    and financial benefits to their shareholders, clients and
    employees, including: increased data acquisition crew capacity, with a
    combined crew count of 21 crews, as currently configured, in the
    continental United States and six in Canada, as well as combined
    channel counts in excess of 210,000 and more than 200 vibrator
    energy source units; a more diversified client mix, including increased
    geographical diversity and access to the Canadian market; expanded service offerings, including those
    leveraging TGCs dynamite source and shot-hole drilling
    capabilities; strong prospects for an expanded client base and
    product offering to allow for new business relationships not
    available to either company on a stand-alone basis; greater crew efficiencies gained through the ability
    to reconfigure crews, leverage and share equipment and personnel
    resources, including by leveraging Canadian resources during
    summer thaw periods; a continued balance of oil and natural gas projects
    and assignments, particularly in oil and liquid-rich basins; expanded support functions, including permit,
    survey, maintenance repair facilities and in-house trucking
    capabilities; better market position to meet client needs with an
    increased ability to service seismic projects in a timely manner
    and to provide higher resolution images with expanded channel
    counts, particularly with respect to unconventional reservoirs; increased opportunities to scale and align crew size
    with project size; the shareholders of Dawson and TGC will have the
    opportunity to participate in the equity value of the combined
    companies and have the benefit of the increased public market
    liquidity resulting from the combined companies larger
    public float and market cap; and opportunities for cost savings and revenue
    generation through enhanced operational logistics.Q:
    
    Why am I being asked to cast a non-binding vote to approve
    certain compensation to be paid by TGC to TGCs named
    executive officers upon consummation of the merger?A:
    
    New SEC rules resulting from The Dodd-Frank Wall Street Reform
    and Consumer Protection Act of 2010, which we refer to as the
    Dodd-Frank Act, require TGC to seek a non-binding vote from its
    shareholders with respect to certain compensation that will be
    paid to TGCs named executive officers by TGC upon
    consummation of the merger. Accordingly, in compliance with the
    Dodd-Frank Act, we are asking TGC vi




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shareholders to approve such compensation. However, even if TGC
    shareholders do not approve such compensation, if all closing
    conditions to the merger are satisfied, Dawson and TGC will be
    obligated to close the merger, and TGCs named executive
    officers will be paid such compensation.Q:
    
    Why is my vote important?A:
    
    Completion of the merger requires the approval of the
    shareholders of Dawson and TGC at their respective special
    meetings. If you do not return your proxy card by mail or submit
    your proxy by telephone or over the Internet or vote in person
    at the special meetings, it may be difficult for Dawson and TGC
    to obtain the necessary quorum to hold their special meetings.In addition, since approval of the merger agreement by the
    shareholders of TGC requires the affirmative vote of at least
    80% of the outstanding shares of TGC common stock, if you are a
    TGC shareholder and you fail to vote, that will have the same
    effect as a vote AGAINST approval of the
    merger agreement.Whether you are a Dawson or TGC shareholder, if you abstain from
    voting, that will have the same effect as a vote
    AGAINST each of the matters proposed at the
    applicable special meeting.Dawsons board of directors recommends that Dawson
    shareholders vote FOR approval of the issuance of
    shares of Dawson common stock to TGC shareholders pursuant to
    the merger agreement and FOR approval of any
    adjournment of the Dawson special meeting, if necessary or
    appropriate, to permit further solicitation of proxies.TGCs board of directors recommends that TGC
    shareholders vote FOR approval of the merger
    agreement, FOR approval of the non-binding advisory
    resolution on certain compensation to be paid by TGC to
    TGCs named executive officers upon consummation of the
    merger and FOR approval of any adjournment of the
    TGC special meeting, if necessary or appropriate, to permit
    further solicitation of proxies. 
  As described under the headings TGC
    Proposal 2  Non-Binding, Advisory Vote on
    Approval of Certain Compensation to be Paid by TGC to TGCs
    Named Executive Officers and The Merger 
    Conflicts of Interests beginning on pages 47 and 89,
    respectively, of this joint proxy statement/prospectus,
    TGCs directors and executive officers will receive
    financial benefits that are different from, or in addition to,
    those of TGCs shareholders. 
  No matter how many shares you own of either Dawson or TGC
    common stock, your vote is important and you are encouraged to
    vote.Q:
    
    What will I receive in the merger in exchange for my shares
    of TGC common stock?A:
    
    Under the merger agreement, TGC shareholders will receive
    0.188 shares of Dawson common stock for every one share of
    TGC common stock they own, provided that the average of the
    volume weighted average price of Dawson common stock on NASDAQ
    during the 10 consecutive trading days ending on
    [  ], 2011 (which is the date that is two
    business days prior to the date of the special meetings) is
    equal to or greater than $32.54 but less than or equal to
    $52.54. We refer to the number of shares of Dawson common stock
    that TGC shareholders will receive for each share of TGC common
    stock they hold as the exchange ratio. In addition, we refer to
    the 10 consecutive trading day average of the volume weighted
    average price of Dawson common stock calculated as described in
    the previous sentence as the
    10-day
    average VWAP of Dawson common stock. 
  In the event that the
    10-day
    average VWAP of Dawson common stock as of [  ],
    2011 is less than $32.54 or greater than $52.54, the parties, at
    their respective option, will be entitled to terminate the
    transaction following two business days of good faith
    negotiations to determine a modified, mutually acceptable
    exchange ratio. See The Merger Agreement 
    Merger Consideration  Determination of the Exchange
    Ratio on page 97. 
 
  If the exchange ratio is modified, Dawson and TGC will each
    disclose the adjustment on a current report on Form 8-K and in a
    press release and will recirculate this joint proxy
    statement/prospectus or a supplement thereto and resolicit
    proxies. 
 vii




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The 10-day
    average VWAP of Dawson common stock as of March 18, 2011,
    the last trading day prior to announcement of the transaction,
    was $44.16. The
    10-day
    average VWAP of Dawson common stock as of the date of this joint
    proxy statement/prospectus was $[  ], which is
    within the trading range required to prevent the exchange ratio
    from being renegotiated or the merger agreement being terminated. 
  Dawson will not issue any fractional shares of its common stock
    in connection with the proposed merger. For each fractional
    share that would otherwise be issued, Dawson will pay cash
    (without interest) in an amount equal to the product of the
    fractional share and the closing price for shares of Dawson
    common stock on NASDAQ on the business day immediately prior to
    the closing date of the merger. See The Merger
    Agreement  Merger Consideration 
    Fractional Shares on page 98. 
  We anticipate that upon completion of the transaction, Dawson
    will have approximately 11.7 million shares of common stock
    outstanding, with current Dawson shareholders owning
    approximately 68% of the combined company and current TGC
    shareholders owning approximately 32%. 
  For additional information regarding what TGC shareholders will
    be entitled to receive pursuant to the merger, see The
    Merger  Merger Consideration on page 87. 
  Q:
    
    What is the value of the merger consideration that TGC
    shareholders are to receive? 
  A:
    
    The number of shares of Dawson common stock to be issued in the
    merger for each share of TGC common stock is fixed (except in
    the event of any stock split, reverse stock split, stock
    dividend, combination, reclassification, recapitalization or
    other similar transaction or event with respect to Dawson common
    stock or TGC common stock) and will not be adjusted for changes
    in the market price of either Dawson common stock or TGC common
    stock unless the
    10-day
    average VWAP of Dawson common stock as of [  ],
    2011 is less than $32.54 or greater than $52.54. Accordingly,
    any change in the price of Dawson common stock prior to the
    merger will affect the market value of the merger consideration
    that TGC shareholders will receive as a result of the merger.
    For additional information regarding the value of the merger
    consideration, see The Merger  The Merger
    Consideration  The Number of Shares of Dawson Common
    Stock to be Issued in the Merger for Each Share of TGC Common
    Stock is Fixed on page 87. 
  The 10-day
    average VWAP of Dawson common stock as of March 18, 2011,
    the last trading day prior to announcement of the transaction,
    was $44.16. The
    10-day
    average VWAP of Dawson common stock as of the date of this joint
    proxy statement/prospectus was $[  ]. However,
    you should obtain current stock price quotations for Dawson
    common stock and TGC common stock before voting. Dawson common
    stock and TGC common stock are listed on NASDAQ under the
    symbols DWSN and TGE, respectively.In the event that the
    10-day
    average VWAP of Dawson common stock as of [  ],
    2011 is less than $32.54 or greater than $52.54, the parties, at
    their respective option, will be entitled to terminate the
    transaction following two business days of good faith
    negotiations to determine a modified, mutually acceptable
    exchange ratio. 
  If the exchange ratio is modified, Dawson and TGC will each
    disclose the adjustment on a current report on
    Form 8-K
    and in a press release and will recirculate this joint proxy
    statement/prospectus or a supplement thereto and resolicit
    proxies. 
  Q:
    
    How likely is it that the
    10-day
    average VWAP of Dawson common stock as of [  ],
    2011 will not be in the designated range, thereby meaning that
    the exchange ratio will need to be renegotiated or the merger
    agreement will be terminated?A:
    
    We cannot predict what the trading price of Dawson common stock
    will be at the effective time of the merger or what the
    10-day
    average VWAP of Dawson common stock will be as of
    [  ], 2011. The
    10-day
    average VWAP of Dawson common stock as of the date of this joint
    proxy statement/prospectus was $[  ], which is
    within the trading range required to prevent the exchange ratio
    from being renegotiated or the merger agreement being terminated. viii




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For additional information regarding how the
    10-day
    average VWAP of Dawson common stock will be calculated, see
    The Merger  The Merger
    Consideration  The Number of Shares of Dawson Common
    Stock to be Issued in the Merger for Each Share of TGC Common
    Stock is Fixed on page 87. 
  Q:
    
    Will Dawson shareholders receive any additional shares as a
    result of the merger?A:
    
    No. Dawson shareholders will not receive any additional
    shares of Dawson common stock as a result of the merger.Q:
    
    What will happen to shares of Dawson common stock in the
    merger? 
  A:
    
    Holders of shares of Dawson common stock will continue to own
    their existing shares, which will not be converted or canceled
    in the merger. In the merger, each outstanding share of TGC
    common share will be converted into the right to receive
    0.188 shares of Dawson common stock provided that the
    10-day
    average VWAP of Dawson common stock as of [  ],
    2011 is equal to or greater than $32.54 but less than or equal
    to $52.54. As of July 8, 2011, there were
    7,910,885 shares of Dawson common stock,
    19,277,770 shares of TGC common stock and outstanding stock
    options to acquire up to 726,440 shares of TGC common stock
    outstanding. Based on such number of shares and options
    outstanding, there would be an aggregate of approximately
    11,671,676 shares of Dawson common stock outstanding after
    completion of the merger, of which approximately 68% of those
    outstanding shares would be held by current Dawson shareholders
    and the remaining approximate 32% would be held by current TGC
    shareholders. 
  Q:
    
    Will the merger affect the board of directors or officers of
    Dawson after the merger? 
  A:
    
    Yes. Under the merger agreement, Dawson has agreed to take all
    necessary actions to cause, as of the effective time of the
    merger, the Dawson board of directors to include as Dawson
    directors Wayne A. Whitener and Allen T. McInnes, each of whom
    is currently a director of TGC. We expect that the current
    directors of Dawson will continue to serve as directors of
    Dawson after the merger. Accordingly, in order to accommodate
    the two additional directors, at the effective time of the
    merger, the Dawson board of directors will increase in size to
    10 directors. See The Merger Agreement 
    Governance Matters on page 97. 
  The current officers of Dawson will continue to serve as the
    officers of Dawson after the merger is complete.Q:
    
    Who is entitled to vote at the Dawson special meeting and the
    TGC special meeting?A:
    
    Dawson shareholders:  The record date for the
    Dawson special meeting is [  ], 2011. Only
    holders of record of shares of Dawson common stock outstanding
    and entitled to vote as of the close of business on the record
    date are entitled to notice of, and to vote at, the Dawson
    special meeting or any adjournment or postponement of the Dawson
    special meeting.TGC shareholders:  The record date for the TGC
    special meeting is [  ], 2011. Only holders of
    record of shares of TGC common stock outstanding and entitled to
    vote as of the close of business on the record date are entitled
    to notice of, and to vote at, the TGC special meeting or any
    adjournment or postponement of the TGC special meeting.Q:
    
    What vote of Dawson shareholders is required to approve the
    transaction with TGC?A:
    
    The affirmative vote of a majority of shares of Dawson common
    stock present in person or represented by proxy and entitled to
    vote at the Dawson special meeting, in which a quorum is
    present, is required to approve the issuance of shares of Dawson
    common stock to TGC shareholders pursuant to the merger
    agreement.Any adjournment of the Dawson special meeting, if necessary or
    appropriate to solicit additional proxies, requires the
    affirmative vote of the holders of Dawson common stock
    representing a majority of the votes present in person or
    represented by proxy and entitled to vote at the Dawson special
    meeting, whether or not a quorum exists. ix




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At the close of business on [  ], 2011, the
    record date for the Dawson special meeting, directors and
    executive officers of Dawson had the right to
    vote [  ]% of the outstanding shares of
    Dawson common stock. Certain of those executive officers and
    directors, who collectively owned approximately
    [  ]% of the shares of Dawson common stock
    outstanding on such date, have entered into a voting agreement
    with TGC, which we refer to as the Dawson shareholder voting
    agreement. Pursuant to and subject to the terms of the Dawson
    shareholder voting agreement, those directors and executive
    officers have agreed, among other things, to vote their shares
    of Dawson common stock in favor of approval of the issuance of
    shares of Dawson common stock in connection with the proposed
    merger at the Dawson special meeting. For additional information
    on the Dawson shareholder voting agreement, see The Dawson
    Shareholder Voting Agreement beginning on page 119. 
 
  For additional information on the vote required to approve the
    issuance of shares of Dawson common stock in connection with the
    proposed merger, see The Dawson Special Meeting
    beginning on page 34. 
  Q:
    
    How does the Dawson board of directors recommend that Dawson
    shareholders vote with respect to the proposed merger? 
  A:
    
    Dawsons board of directors recommends that Dawson
    shareholders vote FORapproval of the
    issuance of shares of Dawson common stock to TGC shareholders
    pursuant to the merger agreement. For additional information on
    the recommendation of Dawsons board of directors, see
    The Merger  Dawsons Reasons for the
    Merger and Recommendation of Dawsons Board of
    Directors beginning on page 60. 
  Q:
    
    What vote of TGC shareholders is required to approve the
    transaction with Dawson and to approve the non-binding advisory
    resolution on certain compensation to be paid by TGC to
    TGCs named executive officers upon consummation of the
    merger?A:
    
    The affirmative vote of at least 80% of the outstanding shares
    of TGC common stock is required to approve the merger agreement.The affirmative vote of a majority of shares of TGC common stock
    present in person or represented by proxy and entitled to vote
    at the TGC special meeting, in which a quorum is present, is
    required to approve the non-binding advisory resolution on
    certain compensation to be paid by TGC to TGCs named
    executive officers upon consummation of the merger. However,
    approval by TGC shareholders of such compensation is not a
    condition to the merger. Accordingly, even if TGC shareholders
    do not approve such compensation, if all closing conditions to
    the merger are satisfied, Dawson and TGC will be obligated to
    close the merger, and TGC named executive officers will be paid
    such compensation.Any adjournment of the TGC special meeting, if necessary or
    appropriate to solicit additional proxies, requires the
    affirmative vote of the holders of TGC common stock representing
    a majority of the votes present in person or represented by
    proxy and entitled to vote at the TGC special meeting, whether
    or not a quorum exists. 
  At the close of business on [  ], 2011, the
    record date for the TGC special meeting, directors and executive
    officers of TGC and their respective affiliates had the right to
    vote [  ]% of the outstanding shares of TGC
    common stock. Those executive officers and directors and their
    affiliates have entered into voting agreements with Dawson,
    which we refer to as the TGC shareholder voting agreements.
    Pursuant to and subject to the terms of the TGC shareholder
    voting agreements, those directors and executive officers and
    their respective affiliates have agreed, among other things, to
    vote their shares of TGC common stock in favor of approval of
    the merger agreement at the TGC special meeting. For additional
    information on the TGC shareholder voting agreements, see
    The TGC Shareholder Voting Agreements beginning on
    page 117. 
 
  For additional information on the vote required to approve the
    merger agreement, see The TGC Special Meeting
    beginning on page 41. 
 x




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Q:
    
    How does the TGC board of directors recommend that TGC
    shareholders vote with respect to the proposed merger and the
    non-binding advisory resolution on certain compensation to be
    paid by TGC to TGCs named executive officers upon
    consummation of the merger? 
  A:
    
    TGCs board of directors recommends that TGC shareholders
    vote FORapproval of the merger agreement.
    For additional information on the recommendation of TGCs
    board of directors, see The Merger  TGCs
    Reasons for the Merger and Recommendation of TGCs Board of
    Directors beginning on page 65. 
  In addition, TGCs board of directors recommends that TGC
    shareholders vote FORapproval of the
    non-binding advisory resolution on certain compensation to be
    paid by TGC to TGCs named executive officers upon
    consummation of the merger. 
  You should note that TGCs directors and executive officers
    have interests in the merger as directors or officers that are
    different from, or in addition to, the interests of other TGC
    shareholders. For information relating to the interests of
    TGCs directors and executive officers in the merger, see
    The Merger  Conflicts of Interests
    beginning on page 89. 
  Q:
    
    What constitutes a quorum for the special meetings?A:
    
    With respect to each special meeting, a majority of the
    outstanding shares of common stock entitled to vote at the close
    of business on the record date being present in person or
    represented by proxy constitutes a quorum for the special
    meeting. While abstentions will be counted for purposes of
    determining whether a quorum is present, broker non-votes (which
    are described below) will not.Q:
    
    When and where are the special meetings? 
  A:
    
    The Dawson special meeting will take place at
    [  ], Dallas, Texas at
    [  ] a.m., central time, on
    [  ], 2011. For additional information relating
    to the Dawson special meeting, see The Dawson Special
    Meeting beginning on page 34. 
 
  The TGC special meeting will take place at [  ],
    Dallas, Texas at [  ] a.m., central time,
    on [  ], 2011. For additional information
    relating to the TGC special meeting, see The TGC Special
    Meeting beginning on page 41. 
  Q:
    
    Is the consummation of the merger subject to any conditions
    other than the approval of Dawson and TGC shareholders?A:
    
    Yes. In addition to Dawson and TGC shareholder approval, the
    consummation of the merger is contingent upon the satisfaction
    or, to the extent permitted by law, waiver of the following
    conditions: clearance under the
    Hart-Scott-Rodino
    Antitrust Improvements Act of 1976, or HSR Act; the absence of any judgment, injunction, order or
    decree in effect, or any law, statute, rule or regulation
    enacted, that prohibits the consummation of the merger; the effectiveness of a registration statement on
    Form S-4
    of which this joint proxy statement/prospectus forms a part and
    the authorization of the listing of the shares of Dawson common
    stock to be issued in the merger on NASDAQ; receipt by each party of an opinion from its
    counsel, in a form and substance reasonably satisfactory to that
    party, dated as of the closing date of the merger, to the effect
    that (1) the merger will be treated as a tax-free
    reorganization within the meaning of Section 368(a) of the
    Internal Revenue Code, or the Code, and (2) no gain or loss
    will be recognized for United States federal income tax purposes
    by the shareholders of TGC upon the exchange of shares of TGC
    common stock for shares of Dawson common stock pursuant to the
    proposed merger; certain officers of TGC having entered into
    employment agreements with TGC, as the surviving entity of the
    merger, as of the effective time of the merger; receipt by TGC of certain third party consents; xi




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 receipt by TGC, as of the closing date, of a
    reconfirmation from its financial advisor that the exchange
    ratio is fair, from a financial point of view, to TGC
    shareholders, which opinion is referred to as the reconfirmation
    opinion; and 
   other customary conditions, including the absence of
    a material adverse effect with respect to either TGCs or
    Dawsons respective businesses. 
  If any of the conditions set forth above fail to occur, the
    merger will not be consummated and the merger agreement will
    terminate. Either party may waive any of their respective
    conditions if the law allows such party to do so, and this could
    include a waiver by TGC of its condition that it shall have
    received, as of the closing date, a reconfirmation from its
    financial advisor that the exchange ratio is fair, from a
    financial point of view, to TGC shareholders. However, TGC does
    not anticipate waiving this condition. If either party were to
    waive a condition, the consummation of the merger would occur
    without the condition having been met. Neither Dawson nor TGC
    can give any assurance regarding when or if all of the
    conditions to the merger will be either satisfied or waived or
    that the merger will occur as intended. 
  The proposal relating to the approval of certain compensation to
    be paid by TGC to TGCs named executive officers upon
    consummation of the merger is a non-binding advisory resolution
    and is not a condition to the merger. Accordingly, even if TGC
    shareholders do not approve such compensation, if all closing
    conditions to the merger are satisfied, Dawson and TGC will be
    obligated to close the merger, and TGC named executive officers
    will be paid such compensation. 
  For additional information on the conditions to the consummation
    of the merger, see The Merger Agreement 
    Conditions to Completion of the Merger beginning on
    page 110. 
  Q:
    
    What do I need to do now?A:
    
    After reading and considering carefully the information
    contained in this joint proxy statement/prospectus, please vote
    promptly by calling the toll-free number listed on your proxy
    card, accessing the Internet website listed on your proxy card
    or completing, signing, dating and returning your proxy card in
    the enclosed postage-paid envelope. If you hold your stock in
    street name through a bank, broker or other nominee,
    you must direct your bank, broker or other nominee to vote in
    accordance with the instructions you have received from your
    bank, broker or other nominee. Submitting your proxy by
    telephone, Internet or mail or directing your bank, broker or
    other nominee to vote your shares will ensure that your shares
    are represented and voted at the special meeting. 
  For additional information on voting procedures, see The
    Dawson Special Meeting beginning on page 34 or
    The TGC Special Meeting beginning on page 41,
    as applicable. 
  Q:
    
    How will my proxy be voted?A:
    
    If you vote by telephone, over the Internet or by completing,
    signing, dating and returning your signed proxy card, your proxy
    will be voted in accordance with your instructions. The proxy
    confers discretionary authority to the named proxies. If you are
    a Dawson shareholder and you complete, sign, date and return
    your proxy card and do not indicate how you want to vote, your
    shares will be voted FOR approval of the
    issuance of shares of Dawson common stock to TGC shareholders
    pursuant to the merger agreement and FOR the
    adjournment of the Dawson special meeting, if necessary or
    appropriate, to permit further solicitation of proxies. If you
    are a TGC shareholder and you complete, sign, date and return
    your proxy card and do not indicate how you want to vote, your
    shares will be voted FOR approval of the
    merger agreement, FOR approval of the
    non-binding advisory resolution on certain compensation to be
    paid by TGC to TGCs named executive officers upon
    consummation of the merger and FOR the
    adjournment of the TGC special meeting, if necessary or
    appropriate, to permit further solicitation of proxies. 
  For additional information on voting procedures, see The
    Dawson Special Meeting beginning on page 34 or
    The TGC Special Meeting beginning on page 41,
    as applicable. 
  Q:
    
    What if my bank, broker or other nominee holds my shares in
    street name? xii




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A:
    
    If a bank, broker or other nominee holds your shares for your
    benefit but not in your own name, your shares are in
    street name. In that case, your bank, broker or
    other nominee will send you a voting instruction form to use in
    voting your shares. The availability of telephone and Internet
    voting depends on the voting procedures of your bank, broker or
    other nominee. Please follow the instructions on the voting
    instruction form they send you. If your shares are held in the
    name of your bank, broker or other nominee and you wish to vote
    in person at your special meeting, you must contact your bank,
    broker or other nominee and request a document called a
    legal proxy. You must bring this legal proxy to your
    respective special meeting in order to vote in person.Q:
    
    What if I dont provide my bank, broker or other nominee
    with instructions on how to vote?A:
    
    Generally, a bank, broker or other nominee may vote the shares
    that it holds for you only in accordance with your instructions.
    However, if your bank, broker or other nominee has not received
    your instructions, your bank, broker or other nominee has the
    discretion to vote on certain matters that are considered
    routine. A broker non-vote occurs if your bank,
    broker or other nominee cannot vote on a particular matter
    because your bank, broker or other nominee has not received
    instructions from you and because the proposal is not routine.
    None of the matters being presented to shareholders for a
    vote at the special meetings of Dawson and TGC is considered a
    routine matter. Therefore, your bank, broker or other nominee
    will not be permitted to vote at the special meeting without
    instruction from you as the beneficial owner of the shares of
    Dawson or TGC common stock.If you do not instruct your bank, broker or other nominee on how
    you want your shares of Dawson common stock or TGC common stock,
    as applicable, to be voted, it may be difficult for Dawson and
    TGC to obtain the necessary quorum to hold their special
    meetings because broker non-votes will not be counted for
    purposes of determining whether a quorum is present at either
    special meeting.In addition, even if there is a quorum present at the TGC
    special meeting, a broker non-vote will have the same effect as
    a vote AGAINST approval of the merger
    agreement. Assuming a quorum is present at the TGC special
    meeting, a broker non-vote will have no effect on the proposal
    to approve the non-binding advisory resolution on certain
    compensation to be paid by TGC to TGCs named executive
    officers upon consummation of the merger. Whether or not a
    quorum is present at the TGC special meeting, a broker non-vote
    will have no effect on the adjournment proposal.In the case of Dawson shareholders, assuming a quorum is present
    at the Dawson special meeting, a broker non-vote will have no
    effect on the proposal to issue shares of Dawson common stock
    pursuant to the merger agreement. Whether or not a quorum is
    present at the Dawson special meeting, a broker non-vote will
    have no effect on the adjournment proposal. 
  For additional information on voting procedures, see The
    Dawson Special Meeting beginning on page 34 or
    The TGC Special Meeting beginning on page 41,
    as applicable. 
  Q:
    
    What if I mark abstain when voting?A:
    
    If you mark abstain when voting, your abstention will still be
    counted in determining whether a quorum is present at the
    applicable special meeting. However, abstentions will have the
    same effect as a vote AGAINST all the matters
    being considered at the applicable special meeting. Accordingly,
    if you are a Dawson shareholder, your abstention will have the
    same effect as a vote AGAINST approval of the
    issuance of shares of Dawson common stock pursuant to the merger
    agreement and AGAINST adjournment of the
    Dawson special meeting, and if you are a TGC shareholder, your
    abstention will have the same effect as a vote
    AGAINST approval of the merger agreement,
    AGAINST approval of the non-binding advisory
    resolution on certain compensation to be paid by TGC to
    TGCs named executive officers upon consummation of the
    merger, and AGAINST adjournment of the TGC
    special meeting.Q:
    
    What should I do if I receive more than one set of voting
    materials for the Dawson special meeting or the TGC special
    meeting?A:
    
    You may receive more than one set of voting materials for the
    Dawson special meeting or the TGC special meeting, including
    multiple copies of this joint proxy statement/prospectus and
    multiple proxy cards or xiii




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voting instruction cards. For example, if you hold your shares
    of Dawson common stock or TGC common stock in more than one
    brokerage account, you will receive a separate voting
    instruction card for each brokerage account in which you hold
    shares. If you are a holder of record and your shares of Dawson
    common stock or TGC common stock are registered in more than one
    name, you will receive more than one proxy card. Please submit
    each separate proxy or voting instruction card that you receive
    by following the instructions set forth in each separate proxy
    or voting instruction card.Q:
    
    What can I do if I want to change or revoke my vote?A:
    
    Regardless of the method you used to cast your vote, if you are
    a holder of record, you may change your vote: by completing, signing, dating and returning a new
    proxy card with a later date so that it is received prior to the
    applicable special meeting; by calling the toll-free number listed on the proxy
    card or by accessing the Internet website listed on the proxy
    card by 11:59 p.m. New York City time on
    [  ], 2011; or by attending the Dawson special meeting or TGC
    special meeting, as applicable, and voting by ballot in person
    at the special meeting. 
  You may also revoke your proxy card by sending a notice of
    revocation, which must be received prior to the applicable
    special meeting, to the designated representative of Dawson or
    TGC, as applicable, at the address provided under Where
    You Can Find More Information beginning on page 150.
    Your attendance at the Dawson or TGC special meeting, as
    applicable, will not, by itself, revoke any proxy that you have
    previously submitted unless you also vote by ballot in person at
    the applicable special meeting. 
  If you hold your shares in street name and wish to
    change or revoke your vote, please refer to the information on
    the voting instruction form included with these materials and
    forwarded to you by your bank, broker, custodian or other record
    holder to see your voting options. 
  For additional information on voting procedures, see The
    Dawson Special Meeting beginning on page 34 or
    The TGC Special Meeting beginning on page 41,
    as applicable. 
  Q:
    
    Is the merger expected to be taxable to TGC shareholders? 
  A:
    
    The merger is intended to qualify as a tax-free reorganization
    under Section 368(a) of the Code. It is a condition to
    closing of the merger that counsel for Dawson and TGC deliver
    opinions to the effect that the merger will qualify as such a
    reorganization. While the condition is waivable, neither Dawson
    nor TGC intends to waive this closing condition. If either party
    were to waive the condition, and the resulting change in tax
    consequences to TGC shareholders would be material, Dawson and
    TGC will recirculate this joint proxy statement/prospectus or a
    supplement thereto and resolicit proxies. 
  Assuming that the merger qualifies as a tax-free reorganization
    and that you are a U.S. person, then you generally will not
    recognize any gain or loss, except with respect to cash you
    receive in lieu of fractional shares of Dawson common stock. 
  You should read Material U.S. Federal Income Tax
    Consequences of the Merger beginning on page 125 for
    a description of the material U.S. federal income tax
    consequences of the merger. Tax matters can be complicated, and
    the tax consequences of the merger to you will depend on your
    particular situation. You are urged to consult your tax
    advisor to determine the tax consequences of the merger to
    you. 
  Q:
    
    What will happen to TGCs stock options and restricted
    stock in the merger?A:
    
    As a result of the merger, each outstanding stock option for TGC
    common stock granted by TGC pursuant to a benefit plan will
    become fully vested prior to the effective time of the merger.
    Stock options for TGC common stock will, if not exercised prior
    to the effective time of the merger, be converted into stock
    options for Dawson common stock on terms substantially identical
    to those in effect immediately prior to xiv




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the effective time of the merger, with the number of shares of
    Dawson common stock issuable and the exercise price being
    adjusted by the exchange ratio.Immediately prior to the effective time of the merger, each
    outstanding award of restricted stock granted by TGC pursuant to
    an employee benefit plan will become fully vested and each
    holder of such formerly restricted shares will have the right to
    participate in the merger as a holder of TGC common stock. 
  For more information, see The Merger Agreement 
    Effect of the Merger on TGCs Equity Awards beginning
    on page 98. 
  Q:
    
    What will happen if TGC shareholders do not approve the
    compensation to be paid by TGC to TGCs named executive
    officers upon consummation of the merger, but all closing
    conditions to the merger are satisfied?A:
    
    The proposal relating to the approval of certain compensation to
    be paid by TGC to TGCs named executive officers upon
    consummation of the merger is a non-binding advisory resolution
    and is not a condition to the merger. Even if TGC shareholders
    do not approve such compensation, if all closing conditions to
    the merger are satisfied, Dawson and TGC will be obligated to
    close the merger, and TGC named executive officers will be paid
    such compensation. 
  For more information, see TGC Proposal 2 
    Non-Binding, Advisory Vote on Approval of Certain Compensation
    to be paid by TGC to TGCs Named Executive Officers
    and The Merger  Conflicts of Interests
    beginning on pages 47 and 89, respectively. 
  Q:
    
    If I am a holder of TGC common stock with shares represented
    by stock certificates, should I send in my TGC stock
    certificates now? 
  A:
    
    NO, TGC SHAREHOLDERS SHOULD NOT SEND STOCK CERTIFICATE(S)
    WITH THE PROXY CARD(S).If the merger is completed, Dawson
    will send TGC shareholders written instructions for sending in
    their stock certificates or, in the case of book-entry shares,
    for surrendering their book-entry shares. See The TGC
    Special Meeting  Solicitation of Proxies
    beginning on page 44, and The Merger
    Agreement  Payment of Merger
    Consideration  Exchange Procedures beginning on
    page 99. 
  Q:
    
    Are Dawson and TGC shareholders entitled to exercise
    dissenters or appraisal rights?A:
    
    No. Neither Dawson nor TGC shareholders are entitled to any
    appraisal or dissenters rights.Q:
    
    Are there any risks in the merger that I should consider?A:
    
    Yes. There are risks associated with all business combinations,
    including the proposed merger. We have described certain of
    these risks and other risks in more detail under Risk
    Factors beginning on page 24.Q:
    
    When do you expect to complete the merger? 
  A:
    
    Dawson and TGC anticipate the closing of the merger to be
    completed third quarter of 2011, subject to the required
    shareholder approvals and satisfaction or waiver of the other
    closing conditions to the transaction, including regulatory
    clearance. For additional information on the conditions to the
    consummation of the merger, see The Merger
    Agreement  Conditions to Completion of the
    Merger beginning on page 110. 
  Q:
    
    Where can I find more information about the companies?A:
    
    Both Dawson and TGC file periodic reports and other information
    with the SEC. You may read and copy this information at the
    SECs public reference facility. Please call the SEC at
    1-800-SEC-0330
    for information about this facility. This information is also
    available through the SECs website at
    http://www.sec.gov.
    Both companies also maintain websites. You can obtain
    Dawsons SEC filings at
    http://www.dawson3d.com
    and you can obtain TGCs SEC filings at
    http://www.tgcseismic.com.
    Neither Dawson nor TGC intends for information contained on or
    accessible through their respective websites to be part of this
    joint proxy statement/prospectus, other than the documents that
    they file with the SEC that are incorporated by reference into
    this joint proxy statement/prospectus. xv




---



##### Table of Contents



In addition, you may obtain some of this information directly
    from the companies. For a more detailed description of the
    information available, see Where You Can Find More
    Information beginning on page 150. 
  Q:
    
    Whom should I call if I have questions about the special
    meeting or the merger?A:
    
    Dawson shareholders should call Morrow & Co., LLC,
    Dawsons proxy solicitor, at
    (800) 607-0088.TGC shareholders should call D.F. King & Co., Inc.,
    TGCs proxy solicitor, at
    (800) 967-4617.If you have more questions about the merger, please call the
    corporate secretary of Dawson at
    (432) 684-3000
    or the corporate secretary of TGC at
    (972) 881-1099. xvi




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##### Table of Contents



SUMMARY  This summary highlights selected information from this
    document and may not contain all of the information that is
    important to you. To understand the merger fully and for a more
    complete description of the terms of the merger, you should read
    carefully this entire document, including the annexes to this
    document, and the other available information referred to under
    Where You Can Find More Information beginning on
    page 150. We encourage you to read the merger agreement,
    the legal document governing the merger, which is attached as
    Annex A to, and incorporated by reference into, this joint
    proxy statement/prospectus. We have included page references in
    the discussion below to direct you to more complete descriptions
    of the topics presented in this summary.
 
 
 The
    Parties to the Merger Agreement (Page 50)  Dawson Geophysical Company
 508 West Wall, Suite 800
 Midland, Texas 79701
 (432) 684-3000
  2-D, 3-D
    TGC Industries, Inc.
 101 East Park Blvd., Suite 955
 Plano, Texas 75074
 (972) 881-1099
  3-D
    6446 Acquisition Corp.
 508 West Wall, Suite 800
 Midland, Texas 79701
 (432) 684-3000
   
 The
    Merger (Page 52)
 1




---



##### Table of Contents



Merger
    Consideration (Page 87)
 
  10-day
  10-day
 
  Form 8-K
 
   
  The
    Number of Shares of Dawson Common Stock to Be Issued in the
    Merger Is Fixed, and Therefore the Value of the Merger
    Consideration Will Fluctuate with the Market Price of Dawson
    Common Stock (Page 87)
 
  10-day
  10-day 10-day
  10-day
 
  Form 8-K
 
 
  Treatment
    of TGC Stock Options and Restricted Stock
    (Page 88)
 2




---



##### Table of Contents



Dawsons
    Reasons for the Merger (Page 60)
 
 
   
 
  TGCs
    Reasons for the Merger (Page 65)
 
 
   
 
 Recommendations
    of the Dawson Board of Directors (Page 60)  recommends that Dawson
    shareholders vote FOR approval of the issuance of
    Dawson common stock to TGC shareholders pursuant to the merger
    agreement and FOR approval of any adjournment of the
    special meeting, if necessary or appropriate to solicit
    additional proxies
 
 
 Recommendations
    of the TGC Board of Directors (Page 65)  recommends that TGC shareholders vote
    FOR approval of the merger agreement,
    FOR approval of the non-binding advisory resolution
    on certain compensation to be paid by TGC to TGCs named
    executive officers upon consummation of the merger and
    FOR approval of any adjournment of the special
    meeting, if necessary or appropriate to solicit additional
    proxies
 
 
   
 
 Opinion
    of Raymond James & Associates, Inc., Financial Advisor
    to Dawson (Page 72)
 3




---



##### Table of Contents



out-of-pocket
 
 Opinion
    of Southwest Securities, Inc., Financial Advisor to TGC
    (Page 78)   
   
  out-of-pocket
 
 Ownership
    of Dawson Following the Merger (Page 89)   
 Board of
    Directors and Management of Dawson Following the Merger
    (Page 89)
 4




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##### Table of Contents



The
    Dawson Special Meeting (Page 34)    
    to approve the issuance of shares of Dawson common stock to TGC
    shareholders pursuant to the merger agreement; and
    to approve any adjournments of the special meeting, if necessary
    or appropriate to solicit additional proxies in favor of the
    foregoing proposal. 
 The TGC
    Special Meeting (Page 41)    
    to approve the merger agreement;
    to approve a non-binding advisory resolution on certain
    compensation to be paid by TGC to TGCs named executive
    officers upon consummation of the merger; and
    to approve any adjournments of the special meeting, if necessary
    or appropriate to solicit additional proxies in favor of
    approval of the merger agreement. 
 Record
    Date (Page 34 for Dawson and page 41 for
    TGC)     
 Votes
    Required to Approve the Proposals (Page 35 for Dawson and
    page 42 for TGC)  Dawson.
  AGAINST
    TGC.
 5




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##### Table of Contents



AGAINST AGAINST
   
 Outstanding
    Shares and Share Ownership of Management (Page 35 for
    Dawson and page 42 for TGC)  Dawson:
 
   
  TGC:
 
   
 
 Conditions
    to Completion of the Merger (Page 110)    
    the approval of the issuance of shares of Dawson common stock
    pursuant to the merger agreement by Dawson shareholders;
    the approval of the merger agreement by TGC shareholders;
    clearance under the HSR Act;
 6




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##### Table of Contents




    the absence of any judgment, injunction, order or decree in
    effect, or any law, statute, rule or regulation enacted, that
    prohibits the consummation of the merger;
    the effectiveness of a registration statement on
    Form S-4
    of which this joint proxy statement/prospectus forms a part and
    the authorization of the listing of the shares of Dawson common
    stock to be issued in the merger on NASDAQ;
    receipt by each party of an opinion from its counsel, in a form
    and substance reasonably satisfactory to that party, dated as of
    the closing date of the merger, to the effect that (1) the
    merger will be treated as a tax-free reorganization within the
    meaning of Section 368(a) of the Code and (2) no gain
    or loss will be recognized for United States federal income tax
    purposes by the shareholders of TGC upon the exchange of shares
    of TGC common stock for shares of Dawson common stock pursuant
    to the proposed merger;
    certain officers of TGC having entered into employment
    agreements with TGC, as the surviving entity of the merger, as
    of the effective time of the merger;
    receipt by TGC of certain third party consents; 
  
    receipt by TGC of the reconfirmation opinion, which is a
    reconfirmation from TGCs financial advisor, as of the
    closing date, that the exchange ratio is fair, from a financial
    point of view, to TGC shareholders which will involve an updated
    review and analysis of the items set forth in the bullet points
    listed on pages 78-79 under THE MERGER 
    Opinion of TGCs Financial Advisor as and to the
    extent TGCs financial advisor deems appropriate; and 
  
    other customary conditions, including the absence of a material
    adverse effect with respect to either TGCs or
    Dawsons respective businesses. 
   
   
 Regulatory
    Requirements (Page 94)  30-day
 7




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##### Table of Contents



Termination
    of the Merger Agreement (Page 112)    
    the merger has not occurred on or before August 31, 2011
    (October 31, 2011 if all conditions, other than
    (1) clearance under the HSR Act or (2) the absence of
    any judgment, injunction, order or decree in effect, or any law,
    statute, rule or regulation enacted, that prohibits the
    consummation of the merger, have been or are capable of being
    fulfilled);
    TGC shareholders have failed to approve the merger agreement at
    the TGC special meeting;
    Dawson shareholders have failed to approve the issuance of
    Dawson common stock pursuant to the merger agreement at the
    Dawson special meeting;
    a governmental authority shall have issued an order, decree or
    ruling or taken any other action permanently restraining,
    enjoining or otherwise prohibiting the merger and that order,
    decree, ruling or other action shall have become final and
    nonappealable;
    the 10-day
    average VWAP of Dawson common stock as of [  ],
    2011 is less than $32.54 or greater than $52.54 and the parties
    have failed, after two business days of good faith negotiation,
    to agree on a new exchange ratio;
    the other party has breached or failed to perform any of its
    representations and warranties, covenants or agreements in the
    merger agreement such that the conditions to the closing of the
    merger agreement would fail and that breach or failure is
    incapable of being cured prior to the termination date or is not
    cured within 30 days after notice of the breach or failure
    to perform;
    either partys board of directors changes, or fails to
    reaffirm when requested by the other party, its recommendation
    that shareholders approve the matters relating to the proposed
    merger;
    prior to obtaining the required approval of its shareholders,
    the terminating party enters into a binding definitive agreement
    providing for a superior proposal (as defined in
    The Merger Agreement  Covenants and
    Agreements  No Solicitation), as long as the
    terminating party has complied in all respects with the
    non-solicitation provisions of the merger agreement and the
    terminating party pays the other party a termination fee of
    $2.35 million and reimburses the other party for up to
    $1.5 million of its
    out-of-pocket
    expenses; or
    TGC shall have not received the reconfirmation opinion and all
    other mutual conditions to the closing of the merger have been
    satisfied. 
 Termination
    Fee and Expense Reimbursement (Page 113)    
    an acquisition proposal relating to at least 50% of TGCs
    common stock or assets is made public and subsequent to such
    public announcement,  
    the merger agreement is terminated due to (1) the merger
    not closing on or before August 31, 2011 (or, in certain
    circumstances, October 31, 2011), (2) TGC shareholders
    not approving the merger agreement or (3) TGC breaching or
    failing to perform any of its representations and warranties,
    covenants or agreements in the merger agreement, and
    TGC enters into a definitive agreement relating to an
    acquisition proposal within one year after termination of the
    merger agreement;
 8




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##### Table of Contents




    TGCs board of directors changes, or fails to reaffirm when
    requested by Dawson, its recommendation that TGC shareholders
    approve the merger agreement; or
    TGC enters into a superior proposal.        
    an acquisition proposal relating to at least 50% of
    Dawsons common stock or assets is made public and
    subsequent to such public announcement,  
    the merger agreement is terminated due to (1) the merger
    not closing on or before August 31, 2011 (or, in certain
    circumstances, October 31, 2011), (2) Dawson
    shareholders not approving the issuance of shares of Dawson
    common stock pursuant to the merger agreement or (3) Dawson
    breaching or failing to perform any of its representations and
    warranties, covenants or agreements in the merger
    agreement, and
    Dawson enters into a definitive agreement relating to an
    acquisition proposal within one year after termination of the
    merger agreement;  
    Dawsons board of directors changes, or fails to reaffirm
    when requested by TGC, its recommendation that Dawson
    shareholders approve the issuance of shares of Dawson common
    stock in connection with the proposed merger; or
    Dawson enters into a superior proposal.    out-of-pocket
 
 Conflicts
    of Interests (Page 89)   
  
    the accelerated vesting of TGCs options to purchase shares
    of TGC common stock held by TGCs directors and executive
    officers beginning 30 days prior to the effective time of
    the merger and the right to receive the merger consideration in
    respect of any such options that are exercised prior to the
    effective time of the merger;
    the accelerated vesting of TGCs restricted stock held by
    TGCs directors and executive officers at the effective
    time of the merger and the right to receive the merger
    consideration in respect of that restricted stock;
    the extension of the
    90-day
    exercise period beginning at the closing of the merger for stock
    options with an exercise price greater than the value of the
    underlying option on March 20, 2011 that are held
 9




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##### Table of Contents



by TGC directors who will no longer be directors of TGC or
    Dawson after the effective time, until September 19, 2012,
    the date on which the options would have expired had there been
    no merger;  
    certain bonuses to be paid to TGCs named executive
    officers upon completion of the merger;
    shares of Dawson restricted stock to be granted to TGCs
    named executive officers upon completion of the merger; and
    employment agreements between TGCs named executive
    officers and TGC, as the surviving entity of the merger. 
   
 
   
 
 Acquisition
    Proposals (Page 104)      
    Dawson or TGC, as applicable, has not breached its
    non-solicitation covenant contained in the merger agreement in
    any material respect;
    the board of directors of Dawson or TGC, as applicable,
    determines in good faith, after receipt of advice from outside
    counsel and its financial advisor, that such acquisition
    proposal constitutes or is reasonably likely to lead to a
    superior proposal; and
    Dawson or TGC, as applicable, enters into a customary
    confidentiality agreement with the person making such
    acquisition proposal, and all such information provided to such
    person has previously been provided to or is provided to the
    other party concurrently with its provision to such person.
 10




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##### Table of Contents



out-of-pocket
  
    until after the third business day following the delivery of
    notice of intent to change its recommendation or terminate the
    merger agreement and enter into an agreement providing for a
    superior proposal by the party taking such action, which we
    refer to as the no-shop party;
    unless during such three business day period, the no-shop party
    shall, and shall cause its financial and legal advisors to, upon
    the other partys request, discuss with the other party in
    good faith any adjustments to the terms and conditions of the
    merger agreement that the other party may propose in response to
    the superior proposal; and
    if, prior to the expiration of such three business day period,
    the other party makes a proposal to adjust the terms and
    conditions of merger agreement that the no-shop partys
    board of directors determines in good faith, after receipt of
    advice from outside legal counsel and a financial advisor of
    nationally recognized reputation, to be at least as favorable as
    the superior proposal.   Risk
    Factors (Page 24)   
 Material
    U.S. Federal Income Tax Consequences of the Merger
    (Page 125)   
   
  You are urged to
    consult your tax advisor for a full understanding of the tax
    consequences of the merger to you.
 
 Accounting
    Treatment (Page 88)
 11




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##### Table of Contents



Listing
    of Dawson Common Stock and Delisting and Deregistration of TGC
    Common Stock (Page 88)     
 Appraisal
    Rights (Page 94)   
 Comparison
    of Shareholder Rights (Page 128)
 12




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##### Table of Contents



FINANCIAL
    SUMMARY Selected
    Historical Financial Data of Dawson  Form 10-K Form 10-Q
 
    Statement
    of Operations Data
  Six Months EndedMarch 31,

Year Ended September 30,2011

2010

2010

2009

2008

2007

2006Operating revenue

$
150,990,000


$
84,915,000


$
205,272,000


$
243,995,000


$
324,926,000


$
257,763,000


$
168,550,000Operating costsOperating expenses


139,893,000



79,147,000



185,588,000



192,839,000



237,484,000



190,117,000



125,848,000General and administrative


5,592,000



3,646,000



7,131,000



7,856,000



6,762,000



6,195,000



4,808,000Depreciation


14,867,000



13,172,000



27,126,000



26,160,000



24,253,000



18,103,000



13,338,000Total operating costs


160,352,000



95,965,000



219,845,000



226,855,000



268,499,000



214,415,000



143,994,000(Loss) income from operations


(9,362,000
)


(11,050,000
)


(14,573,000
)


17,140,000



56,427,000



43,348,000



24,556,000Other income (expense)


613,000



155,000



583,000



575,000



(20,000
)


1,110,000



657,000(Loss) income before income tax


(8,749,000
)


(10,895,000
)


(13,990,000
)


17,715,000



56,407,000



44,458,000



25,213,000Income tax benefit (expense)


2,225,000



3,973,000



4,638,000



(7,493,000
)


(21,400,000
)


(17,300,000
)


(9,358,000
)Net (loss) income


(6,524,000
)


(6,922,000
)


(9,352,000
)


10,222,000



35,007,000



27,158,000



15,855,000Basic (loss) income per common share


(0.84
)


(0.89
)


(1.20
)


1.31



4.57



3.57



2.11Diluted (loss) income per common share


(0.84
)


(0.89
)


(1.20
)


1.30



4.53



3.54



2.09
 13




---



##### Table of Contents



Balance
    Sheet Data (at period end)
  March 31,

September 30,2011

2010

2010

2009

2008

2007

2006Current assets:Cash and cash equivalents

$
13,602,000


$
19,117,000


$
29,675,000


$
36,792,000


$
8,311,000


$
14,875,000


$
8,064,000Short-term investments


5,500,000



30,123,000



20,012,000



25,267,000











6,437,000Accounts receivable, net of allowance for doubtful accounts


68,704,000



54,009,000



57,726,000



40,106,000



76,221,000



56,707,000



46,074,000Prepaid expenses and other assets


11,951,000



7,143,000



7,856,000



7,819,000



877,000



815,000



690,000Current deferred tax asset


1,795,000



921,000



1,764,000



1,694,000



873,000



693,000



1,619,000Total current assets


101,552,000



111,313,000



117,033,000



111,678,000



86,282,000



73,090,000



62,884,000Property, plant and equipment, net


139,062,000



128,011,000



118,043,000



125,479,000



147,339,000



122,772,000



86,534,000Total assets


240,614,000



239,324,000



235,076,000



237,157,000



233,621,000



195,862,000



149,418,000Current liabilities:Accounts payable


19,748,000



16,894,000



14,274,000



6,966,000



15,308,000



12,816,000



16,280,000Revolving line of credit






















5,000,000



Payroll costs and other taxes


4,231,000



3,160,000



3,625,000



2,720,000



3,363,000



2,325,000



1,958,000Other


8,426,000



9,822,000



7,963,000



10,600,000



14,869,000



14,263,000



4,195,000Deferred revenue


3,994,000



1,512,000



204,000



2,230,000



993,000



2,922,000



863,000Total current liabilities


36,399,000



31,388,000



26,066,000



22,516,000



34,533,000



37,326,000



23,296,000Deferred tax liability


19,188,000



15,987,000



18,785,000



16,262,000



13,128,000



9,381,000



6,914,000Shareholders equity


185,027,000



191,949,000



190,225,000



198,379,000



185,960,000



149,155,000



119,208,000Total liabilities and shareholders equity


240,614,000



239,324,000



235,076,000



237,157,000



233,621,000



195,862,000



149,418,000   Statement
    of Cash Flows Data
  Six Months EndedMarch 31,

Year Ended September 30,2011

2010

2010

2009

2008

2007

2006Cash flows from operating activities

$
3,089,000


$
2,510,000


$
6,244,000


$
54,598,000


$
50,930,000


$
51,427,000


$
25,743,000Cash flows from investing activities


(19,459,000
)


(20,185,000
)


(13,365,000
)


(26,538,000
)


(53,240,000
)


(51,664,000
)


(21,031,000
)Cash flows from financing activities


297,000







4,000



421,000



(4,254,000
)


7,048,000



549,000Capital expenditures, net of noncash capital expenditures


(35,340,000
)


(15,220,000
)


(18,835,000
)


(4,192,000
)


(53,269,000
)


(58,701,000
)


(35,477,000
)
 14




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##### Table of Contents



Selected
    Historical Consolidated Financial Data of TGC  Form 10-K Form 10-Q
 
    Statement
    of Operations Data
  Quarter EndedMarch 31,

Year Ended December 31,2011

2010

2010

2009

2008

2007

2006Operating revenue

$
50,247,313


$
30,293,841


$
108,318,801


$
90,431,899


$
86,769,742


$
90,395,872


$
67,760,306Operating costs and expensesCost of services


34,269,694



23,586,031



85,932,862



65,379,612



55,935,068



60,445,783



40,831,650Selling, general and administrative


2,500,558



1,685,037



6,894,500



5,522,939



4,468,883



3,864,810



2,988,892Depreciation and amortization


4,462,879



3,867,714



15,343,804



14,621,237



13,911,124



12,743,065



9,540,171Total operating costs


41,233,131



29,138,782



108,171,166



85,523,788



74,315,075



77,053,658



53,360,713Income from operations


9,014,182



1,155,059



147,635



4,908,111



12,454,667



13,342,214



14,399,593Interest expense


190,840



215,612



790,417



1,020,681



929,656



604,616



780,782(Loss) income before income tax


8,823,342



939,447



(642,782
)


3,887,430



11,525,011



12,737,598



13,618,811Income tax expense


3,059,608



388,940



579,900



2,007,811



4,626,569



5,130,165



5,507,386Net (loss) income


5,763,734



550,507



(1,222,682
)


1,879,619



6,898,442



7,607,433



8,111,425Basic (loss) income per common share(1)


0.30



0.03



(0.06
)


0.10



0.36



0.40



0.43Diluted (loss) income per common share(1)


0.30



0.03



(0.06
)


0.10



0.36



0.40



0.42     (1)
    
    All per share amounts for the periods presented above have been
    adjusted to reflect stock dividends paid to TGC shareholders of
    record during the applicable periods.
 15




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##### Table of Contents



Balance
    Sheet Data (at period end)
  March 31,

December 31,2011

2010

2010

2009

2008

2007

2006Current assets:Cash and cash equivalents

$
15,465,624


$
23,228,566


$
13,072,503


$
25,504,149


$
24,114,351


$
4,503,826


$
9,388,769Trade accounts receivable, net of allowance for doubtful accounts


27,694,472



19,626,308



17,166,709



9,455,224



5,853,908



12,391,113



7,448,602Cost and estimated earnings in excess of billings on uncompleted
    contracts


2,858,955



51,627



4,578,580



474,059



2,300,985



535,143



989,451Prepaid expenses and other assets


726,110



367,500



1,600,450



648,872



718,301



712,614



508,925Prepaid federal and state income tax










1,219,165



943,600



1,220,154



100,418



192,780Total current assets


46,745,161



43,274,001



37,637,407



37,025,904



34,207,699



18,005,499



18,528,527Property, plant and equipment, net


53,138,403



45,535,321



49,715,626



47,583,333



50,632,563



42,930,385



37,648,646Goodwill and other assets


264,709



1,495,956



262,364



1,440,488



250,659



226,172



222,347Total assets


100,148,273



90,305,278



87,615,397



86,049,725



85,090,921



61,162,056



56,399,520Current liabilities:Trade accounts payable


13,469,933



7,537,660



9,261,238



4,126,474



4,569,911



2,931,264



4,951,985Accrued liabilities


3,325,779



1,680,440



1,808,149



1,337,437



863,756



1,724,078



1,111,023Billings in excess of costs and estimated earnings on
    uncompleted contracts


5,809,895



8,019,769



5,486,017



7,077,941



5,776,444



3,340,220



6,159,514Federal and state income taxes payable


2,048,322



471,348



















415,501Current maturities on notes payable


5,473,095



6,086,963



6,316,852



6,407,892



5,171,872



3,301,903



3,629,395Current maturities of capital lease obligations


1,148,097



919,731



1,071,263



780,526



856,673



1,218,737



1,082,729Total current liabilities


31,275,121



24,715,911



23,943,519



19,730,270



17,238,656



12,516,202



17,350,147Notes payable, less current maturities


3,785,883



4,626,042



4,718,492



5,875,390



10,851,621



3,090,191



2,046,908Capital lease obligations, less current maturities


1,380,399



1,074,760



1,302,963



631,757



600,214



679,074



1,017,154Long-term deferred tax liability


4,297,004



6,075,389



4,787,623



7,117,030



5,973,000



1,955,047



942,153Shareholders equity


59,409,866



53,813,176



52,862,800



52,695,278



50,427,430



42,921,542



35,043,158Total liabilities and shareholders equity


100,148,273



90,305,278



87,615,397



86,049,725



85,090,921



61,162,056



56,399,520   Statement
    of Cash Flows Data
  Quarter EndedMarch 31,

Year Ended December 31,2011

2010

2010

2009

2008

2007

2006Cash flows from operating activities

$
9,084,205


$
418,634


$
5,160,283


$
20,698,122


$
33,860,082


$
14,839,414


$
28,684,807Cash flows from investing activities


(4,568,187
)


(702,771
)


(8,055,970
)


(10,942,164
)


(6,078,536
)


(12,661,703
)


(22,889,549
)Cash flows from financing activities


(2,116,526
)


(2,011,752
)


(9,549,811
)


(8,367,479
)


(8,171,021
)


(7,062,654
)


(5,905,898
)Capital expenditures, paid in cash


(4,623,531
)


(703,452
)


(8,220,293
)


(1,349,972
)


(6,322,048
)


(13,008,088
)


(21,219,238
)
 16




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##### Table of Contents



Selected
    Unaudited Pro Forma Condensed Combined Consolidated Financial
    and Other Information   
  Form 10-K Form 10-Q
 
  and/or
 17




---



##### Table of Contents



10-day
    Six Months Ended

Year EndedMarch 31, 2011

September 30, 2010Pro Forma Income Statement Data:Operating revenue

$
240,149,000


$
323,875,000Income (loss) from operations


2,615,000



(17,075,000
)Income (loss) before income tax


3,097,000



(16,955,000
)Net income (loss)


1,357,000



(12,042,000
)Basic income (loss) per common share


0.12



(1.06
)Diluted income (loss) per common share


0.12



(1.06
)   As ofMarch 31, 2011Pro Forma Balance Sheet Data:Total current assets

$
148,974,000Net property, plant and equipment


212,545,000Intangibles


22,850,000Goodwill


39,289,000Total assets

$
424,019,000Total current liabilities


71,003,000Total shareholders equity


309,283,000Total liabilities and shareholders equity


424,019,000   Other
    Information
  Dawson

TGC

Pro Forma CombinedCrew counts(1)


14



13



27Total channels(1)


140,000



72,000



212,000     (1)
    
    As of March 31, 2011.
 18




---



##### Table of Contents



COMPARATIVE
    PER SHARE MARKET PRICE AND DIVIDEND INFORMATION Dawson
    Historical Market Price Data and Dividends    
 DawsonCommon StockFiscal Year Ended

High

LowSeptember 30, 2009:First Quarter

$
46.15


$
14.31Second Quarter


22.23



9.96Third Quarter


31.42



13.13Fourth Quarter


35.98



23.60September 30, 2010:First Quarter


29.61



21.00Second Quarter


32.00



21.68Third Quarter


31.22



20.58Fourth Quarter


26.91



20.05September 30, 2011:First Quarter


31.90



24.16Second Quarter


50.81



30.50Third Quarter


47.02



30.00Fourth Quarter (through July 19, 2011)


36.46



32.79
 19




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##### Table of Contents



TGC
    Historical Market Price Data and Dividends    
 TGCCommon StockFiscal Year Ended

High

LowDecember 31, 2009:First Quarter

$
2.93


$
1.69Second Quarter


5.75



2.13Third Quarter


5.17



3.30Fourth Quarter


5.03



3.61December 31, 2010:First Quarter


4.64



3.52Second Quarter


4.40



2.82Third Quarter


4.00



2.82Fourth Quarter


3.87



3.07December 31, 2011:First Quarter


7.97



3.59Second Quarter


8.74



5.46Third Quarter (through July 19, 2011)


6.79



6.11  
        Value of
    Merger Consideration  10-day 10-day 10-day 10-day
  10-day
 20




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##### Table of Contents



Aggregate


ApproximateNumber of


PercentageShares of


Ownership ofImplied Value


Dawson


TGCof One Share


Common


ShareholdersDawson


Merger


of TGC


Stock to be


in theCommon


Exchange


Common


Issued to TGC


CombinedStock Price


Ratio


Stock


Shareholders


EntityPrice of Dawson common stock on March 18, 2011

$
42.54



0.188
x

$
8.00



3,753,685



32
%10-day
    average VWAP of Dawson common stock on [  ], 2011


[  ]



0.188
x


[  ]



3,753,685



32
%Maximum
    10-day
    average VWAP of Dawson common stock


52.54



0.188
x


9.88



3,753,685



32
%Minimum
    10-day
    average VWAP of Dawson common stock


32.54



0.188
x


6.12



3,753,685



32
%  Comparative
    Per Share Information    
    the closing prices per share and aggregate market value of
    Dawson common stock and TGC common stock, in each case based on
    the last reported sales prices as reported by NASDAQ, on
    (1) March 18, 2011, the last full trading day before
    the public announcement of the proposed merger, and (2)
    [  ], 2011, the last practicable full trading
    day prior to the mailing of this joint proxy
    statement/prospectus; and
    the equivalent price per share and equivalent market value of
    shares of TGC common stock, reflecting the fluctuating value of
    Dawson common stock that TGC shareholders would receive for each
    share of TGC common stock if the merger were completed on either
    March 18, 2011 or [  ], 2011. The
    equivalent price per share of TGC common stock is calculated
    assuming that the
    10-day
    average VWAP of Dawson common stock as of March 18, 2011 or
    [  ], 2011, as applicable, is equal to or
    greater than $32.54 but less than or equal to $52.54, and is
    equal to the closing price of a share of Dawson common stock on
    the applicable date multiplied by 0.188.  Dawson

TGC

TGCHistorical

Historical

EquivalentMarch 18, 2011Closing price per common share

$
42.54


$
6.83


$
8.00Market value of common stock (in millions)(1)


336.9



131.2



153.7[  ], 2011Closing price per common share


[  ]



[  ]



[  ]Market value of common stock (in millions)(2)


[  ]



[  ]



[  ]     (1)
    
    Based on 7,918,989 shares of Dawson common stock and
    19,212,708 shares of TGC common stock outstanding as of
    March 18, 2011 (excluding outstanding shares held in
    treasury).(2)
    
    Based on [  ] shares of Dawson common stock
    and [  ] shares of TGC common stock
    outstanding as of [  ], 2011 (excluding
    outstanding shares held in treasury).  Number of
    Record and Beneficial Owners
 21




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##### Table of Contents



UNAUDITED
    COMPARATIVE PER SHARE DATA  Form 10-K Form 10-Q
 
  10-day
 
   
  Dawson Pro

TGC ProDawson



Forma

FormaHistorical per

TGC Historical

Combined per

Combined perShare Data

per Share Data

Share Data

Share DataAs of or for the Year Ended September 30, 2010:Income from continuing operations per common share:Basic(1)

$
(1.20
)

$
(0.06
)

$
(1.06
)

$
(0.20
)Diluted(1)


(1.20
)


(0.06
)


(1.06
)


(0.20
)Total tangible book value per common share


29.75



4.54



N/A



N/ABook value of shareholders equity per common share(2)


24.07



2.67



N/A



N/A     (1)
    
    The pro forma combined consolidated statement of income for the
    year ended September 30, 2010 was prepared by combining
    Dawsons historical statement of income for the year ended
    September 30, 2010
 22




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##### Table of Contents



and TGCs historical consolidated statement of income for
    the year ended December 31, 2010, adjusted to give effect
    to pro forma events that are (a) directly attributable to
    the merger, (b) factually supportable and (c) expected
    to have a continuing impact on combined results.(2)
    
    Historical book value per share is computed by dividing
    shareholders equity by the number of shares of Dawson or
    TGC common stock outstanding, as applicable.  Dawson Pro

TGC ProDawson



Forma

FormaHistorical per

TGC Historical

Combined per

Combined perShare Data

per Share Data

Share Data

Share DataAs of or for the Six Months Ended March 31, 2011:Income from continuing operations per common share:Basic(1)

$
(0.84
)

$
0.34


$
0.12


$
0.02Diluted(1)


(0.84
)


0.33



0.12



0.02Total tangible book value per common share


30.38



5.18



31.34



5.89Book value of shareholders equity per common share(2)


23.36



3.09



26.81



5.04     (1)
    
    The pro forma combined consolidated statement of income for the
    six months ended March 31, 2011 was prepared by combining
    Dawsons historical statement of income for the six months
    ended March 31, 2011 and TGCs historical consolidated
    statement of income for the fourth quarter ended
    December 31, 2010 and the first quarter ended
    March 31, 2011, adjusted to give effect to pro forma events
    that are (a) directly attributable to the merger,
    (b) factually supportable and (c) expected to have a
    continuing impact on combined results.(2)
    
    Historical book value per share is computed by dividing
    shareholders equity by the number of shares of Dawson or
    TGC common stock outstanding, as applicable. Pro forma book
    value per share is computed by dividing pro forma total equity
    by the pro forma number of shares of Dawson common stock that
    would have been outstanding as of March 31, 2011.
 23




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##### Table of Contents



RISK
    FACTORS  In addition to the other information contained or
    incorporated by reference into this joint proxy
    statement/prospectus, including the matters addressed in
    Cautionary Statements Concerning Forward-Looking
    Statements on page 32 of this joint proxy
    statement/prospectus, you should carefully consider the
    following risk factors in determining whether to vote for
    approval of the merger agreement. You should also read and
    consider the risk factors associated with each of the businesses
    of Dawson and TGC because these risk factors may affect the
    operations and financial results of Dawson after the merger.
    Those risk factors may be found in Dawsons Annual Report
    on
    Form 10-K
    for the year ended September 30, 2010, and in TGCs
    Annual Report on
    Form 10-K
    for the year ended December 31, 2010, each of which is on
    file with the SEC and is incorporated by reference into this
    joint proxy statement/prospectus.
 
  The
    merger is subject to certain closing conditions which may not be
    satisfied, and as a result, the merger may not be
    completed.
    
    the approval of the issuance of shares of Dawson common stock
    pursuant to the merger agreement by Dawson shareholders;
    the approval of the merger agreement by TGC shareholders;
    clearance under the HSR Act;
    the absence of any judgment, injunction, order or decree in
    effect, or any law, statute, rule or regulation enacted, that
    prohibits the consummation of the merger;
    the effectiveness of a registration statement on
    Form S-4
    of which this joint proxy statement/prospectus forms a part and
    the authorization of the listing of the shares of Dawson common
    stock to be issued in the merger on NASDAQ;
    receipt by each party of an opinion from its counsel, in a form
    and substance reasonably satisfactory to that party, dated as of
    the closing date of the merger, to the effect that (1) the
    merger will be treated as a tax-free reorganization within the
    meaning of Section 368(a) of the Code and (2) no gain or
    loss will be recognized for United States federal income tax
    purposes by the shareholders of TGC upon the exchange of shares
    of TGC common stock for shares of Dawson common stock pursuant
    to the proposed merger;
    certain officers of TGC having entered into employment
    agreements with TGC, as the surviving entity of the merger, as
    of the effective time of the merger;
    receipt by TGC of certain third party consents; 
  
    receipt by TGC of the reconfirmation opinion, which is a
    reconfirmation from TGCs financial advisor, as of the
    closing date, that the exchange ratio is fair, from a financial
    point of view, to TGC shareholders; and 
  
    other customary conditions, including the absence of a material
    adverse effect with respect to either TGCs or
    Dawsons respective businesses.   24




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##### Table of Contents



Dawson
    and TGC must obtain required approvals and governmental and
    regulatory clearances to complete the merger, which, if delayed,
    not granted or granted with unacceptable conditions, may
    jeopardize or delay the merger, result in additional
    expenditures of money and resources and/or reduce the
    anticipated benefits of the merger.
        The
    date that TGC shareholders will receive the merger consideration
    is uncertain.
      Because
    the market price of Dawson common stock will fluctuate, TGC
    shareholders cannot be sure of the aggregate value of the merger
    consideration they will receive.
  10-day
 25




---



##### Table of Contents



10-day
  Because the date that the merger becomes effective may be
    later than the date of the special meetings, at the time of the
    TGC special meeting, TGC shareholders will not know the exact
    market value of the Dawson common stock that they will receive
    upon completion of the merger.
 
  10-day
 
  Whether
    or not the merger is completed, the announcement and pendency of
    the merger could cause disruptions in the businesses of Dawson
    and TGC, which could have an adverse effect on each of their
    respective businesses, financial results and stock
    prices.
    TGC
    may have difficulty attracting, motivating and retaining
    employees in light of the merger, and the anticipated benefits
    of the merger could be reduced.
      The
    merger agreement restricts Dawsons and TGCs ability
    to pursue alternatives to the merger and requires Dawson and TGC
    to pay a termination fee to the other party of
    $2.35 million if it does.
   26




---



##### Table of Contents



TGCs
    directors and executive officers have interests in the merger
    that are different from, and in addition to, the interests of
    other TGC shareholders.
 
 
   
  Failure
    to complete the merger could negatively impact the stock price
    and the future business and financial results of Dawson, TGC or
    both.
    
    each of Dawson and TGC may experience negative reactions from
    its clients and employees;
    the current market price of each of Dawsons and TGCs
    common stock may reflect a market assumption that the merger
    will occur and a failure to complete the merger could result in
    a negative perception by the stock market and a resulting
    decline in the market price of Dawsons common stock or
    TGCs common stock;
    certain costs relating to the merger, including certain
    investment banking, financing, legal and accounting fees and
    expenses, must be paid even if the merger is not
    completed; and
    there may be substantial disruption to each companys
    business and distraction of each companys management and
    employees from
    day-to-day
    operations because matters related to the merger (including
    integration planning) may require substantial commitments of
    time and resources, which could otherwise have been devoted to
    other opportunities that could have been beneficial to the
    companies. 
   
  The
    market for Dawson common stock may be adversely affected by the
    issuance of shares pursuant to the proposals before Dawson
    shareholders.
 
   
 27




---



##### Table of Contents



The
    issuance of shares of Dawson common stock to TGC shareholders in
    the merger will substantially reduce the percentage ownership
    interest of current Dawson shareholders; additionally, TGC
    shareholders, who will own approximately 32% of Dawson common
    stock immediately after the merger, will exercise significantly
    less influence over management after the merger.
 
   
      Dawsons
    actual financial position and results of operations may differ
    materially from the unaudited pro forma financial data included
    herein.
      The
    market price of Dawson common stock after the merger might be
    affected by factors different from, or in addition to, those
    currently affecting the respective market prices of Dawson and
    TGC common stock.
 
   
 28




---



##### Table of Contents



Dawson
    may not pay dividends in the foreseeable future, and current TGC
    shareholders may have to rely on increases in the trading price
    of Dawson common stock for returns on their investment following
    the merger.
    After
    completion of the merger, Dawson may fail to realize the
    anticipated benefits of the merger, which could adversely affect
    the value of Dawsons common stock.
      
    integrating the companies strategies, cultures and
    operations;
    retaining existing TGC and Dawson clients and suppliers;
    adopting best practices across the combined entity and
    harmonizing the companies operating practices, employee
    development and compensation programs, internal controls and
    other policies, procedures and processes;
    integrating the companies corporate, administrative and
    information technology infrastructure; and
    managing any tax costs or inefficiencies associated with
    integration.  day-to-day
  Our
    results of operations could be materially adversely affected if
    we were required to recognize asset impairments of intangibles
    or goodwill associated with the merger.
 
   
 29




---



##### Table of Contents



Form 10-K
 
  The
    unaudited prospective financial information of each of Dawson
    and TGC included in this joint proxy statement/prospectus
    involves risks, uncertainties and assumptions, many of which are
    beyond the control of Dawson and TGC, respectively. As a result,
    such information may not prove to be accurate and is not
    necessarily indicative of current values or future
    performance.
 
 
   
 
   
 
  
    necessarily makes numerous assumptions, many of which are beyond
    the control of Dawson or TGC and may not prove to be accurate; 
 
  
    does not necessarily reflect revised prospects for Dawsons
    or TGCs respective businesses, changes in general business
    or economic conditions, or any other transaction or event that
    has occurred or that may occur and that was not anticipated at
    the time the unaudited prospective financial information was
    prepared; 
 
  
    is not necessarily indicative of future performance, which may
    be significantly more favorable or less favorable than is
    reflected in the unaudited prospective financial
    information; and 
 
  
    should not be regarded as a representation that the unaudited
    prospective financial information will be achieved. 
 
   
  The
    rights of TGC shareholders will be governed by Dawsons
    Second Restated Articles of Incorporation and Second Amended and
    Restated Bylaws.
   30




---



##### Table of Contents



If the
    merger does not qualify as a reorganization under
    Section 368(a) of the Code, TGC shareholders may be
    required to pay substantial U.S. federal income
    taxes.
 
   
 31




---



##### Table of Contents



CAUTIONARY
    STATEMENTS CONCERNING FORWARD-LOOKING STATEMENTS    
    the expected closing date of the merger;
    the anticipated benefits of the merger; and
    the expected tax treatment of the merger for U.S. federal
    income tax purposes.    Forms 10-K, 10-Q, 8-K
    Factors relating to the merger:
  
    whether the merger will be consummated, including whether we
    will receive the required clearance under the HSR Act;
    the failure to receive the required shareholder and regulatory
    approvals for the merger or to satisfy all of the closing
    conditions to the merger;
    the timing of the completion of the merger;
    the value of the merger consideration and the likelihood that
    the exchange ratio will not need to be renegotiated;
    changes in economic, business, competitive
    and/or
    regulatory factors;
    changes in both companies businesses during the period
    between now and the completion of the merger might have adverse
    impacts on Dawson following the merger;
    attrition in key clients, partners, personnel and other
    relationships relating to the merger;
    the expenses of the merger being greater than anticipated,
    including as a result of unexpected factors or events;
    the exposure to litigation, including the possibility that
    litigation relating to the merger could delay or impede the
    completion of the merger; 32




---



##### Table of Contents




    the integration of TGCs business and operations with those
    of Dawson taking longer than anticipated, being costlier than
    anticipated and having unanticipated adverse results relating to
    Dawsons or TGCs existing businesses; and
    uncertainty of the expected financial performance of Dawson
    following completion of the proposed transaction, which may
    differ significantly from the pro forma financial data contained
    in this joint proxy statement/prospectus;  Factors relating to Dawsons and TGCs respective
    businesses:
  
    the potential for fluctuations in oil and natural gas prices;
    the dependence upon energy industry spending for seismic data
    acquisition services; 
  
    the potential for data acquisition contract delays, reductions
    or cancellation; 
  
    high fixed costs of operations;
    external factors affecting either companys crews, such as
    weather interruptions and inability to obtain land access rights
    of way;
    whether Dawson or TGC enter into turnkey or dayrate contracts;
    crew productivity;
    the limited number of clients;
    the credit risk related to clients; and
    the availability of capital resources. 
   
 33




---



##### Table of Contents



THE
    DAWSON SPECIAL MEETING   Date,
    Time and Place   Purpose       Board
    Recommendations  recommends that Dawson
    shareholders vote FOR approval of the issuance of
    Dawson common stock to TGC shareholders pursuant to the merger
    agreement and FOR approval of any adjournment of the
    special meeting, if necessary or appropriate to solicit
    additional proxies
 
 Record
    Date; Outstanding Shares; Shares Entitled to Vote   Quorum   34




---



##### Table of Contents



Required
    Vote  AGAINST
  AGAINST
 Tabulation
    of the Votes   Stock
    Ownership of and Voting by Dawsons Directors and Executive
    Officers   
 Voting of
    Shares by Holders of Record    
    Telephone.  You can vote by telephone by
    calling the toll-free number
    (800) 690-6903
    in the United States, Canada or Puerto Rico on a touch-tone
    telephone. You will then be prompted to enter the control number
    printed on Dawsons proxy card, as applicable, and to
    follow the subsequent instructions. Telephone voting is
    available 24 hours a day until 11:59 p.m. New York
    City time on [  ], 2011. If you vote by
    telephone, you do not need to return your proxy card or voting
    instruction card.
    Internet.  You can vote over the Internet by
    accessing the website at
    http://www.proxyvote.com
    and following the instructions on the secure website. Internet
    voting is available 24 hours a day until 35




---



##### Table of Contents



11:59 p.m. New York City time on [  ],
    2011. If you vote over the Internet, you do not need to return
    your proxy card or voting instruction card.  
    Mail.  You can vote by mail by completing,
    signing, dating and mailing your proxy card or voting
    instruction card in the postage-paid envelope included with this
    joint proxy statement/prospectus.    FOR FOR
   Voting of
    Shares Held in Street Name      AGAINST
 36




---



##### Table of Contents



Revocability
    of Proxies; Changing Your Vote    
    by completing, signing, dating and returning a new proxy card
    with a later date so that it is received prior to the Dawson
    special meeting;
    by calling the toll-free number listed on the proxy card or by
    accessing the Internet website listed on the proxy card by
    11:59 p.m. New York City time on [  ],
    2011; or
    by attending the Dawson special meeting and voting by ballot in
    person at the Dawson special meeting. 
   
   Solicitation
    of Proxies  out-of-pocket out-of-pocket
  Dawson shareholders should not submit any stock certificates
    with their proxy cards.
 No Other
    Business   Adjournments
    and Postponements   37




---



##### Table of Contents



Assistance  (800) 607-0088 (800) 654-2468).
 38




---



##### Table of Contents



DAWSON
    PROPOSAL 1  APPROVAL OF THE ISSUANCE OF
    SHARES OF DAWSON COMMON STOCK TO TGC SHAREHOLDERS PURSUANT
    TO THE MERGER AGREEMENT   
    The Dawson board of directors recommends that Dawson
    shareholders vote FOR approval of the issuance of
    shares of Dawson common stock pursuant to the merger
    agreement.
 39




---



##### Table of Contents



DAWSON
    PROPOSAL 2  ADJOURNMENT OF THE DAWSON SPECIAL
    MEETING    The Dawson board of directors recommends that Dawson
    shareholders vote FOR any adjournment of the Dawson
    special meeting, if necessary or appropriate, to permit further
    solicitation of proxies.
 40




---



##### Table of Contents



THE TGC
    SPECIAL MEETING   Date,
    Time and Place   Purpose         Board
    Recommendations  recommends that TGC shareholders vote
    FOR approval of the merger agreement,
    FOR approval of the non-binding advisory resolution
    on certain compensation to be paid by TGC to TGCs named
    executive officers upon consummation of the merger and
    FOR approval of any adjournment of the special
    meeting, if necessary or appropriate to solicit additional
    proxies
 
 
   
 Record
    Date; Outstanding Shares; Shares Entitled to Vote   Quorum   41




---



##### Table of Contents



Required
    Vote  AGAINST
  AGAINST
  AGAINST
 Tabulation
    of the Votes   Stock
    Ownership of and Voting by TGCs Directors and Executive
    Officers   
 Voting of
    Shares by Holders of Record    
    Telephone.  You can vote by telephone by
    calling the toll-free number
    (800) 690-6903
    in the United States, Canada or Puerto Rico on a touch-tone
    telephone. You will then be prompted to enter the control number
    printed on TGCs proxy card, as applicable, and to follow
    the subsequent 42




---



##### Table of Contents



instructions. Telephone voting is available 24 hours a day
    until 11:59 p.m. New York City time on
    [  ], 2011. If you vote by telephone, you do not
    need to return your proxy card or voting instruction card.  
    Internet.  You can vote over the Internet by
    accessing the website at
    http://www.proxyvote.com
    and following the instructions on the secure website. Internet
    voting is available 24 hours a day until 11:59 p.m.
    New York City time on [  ], 2011. If you vote
    over the Internet, you do not need to return your proxy card or
    voting instruction card.
    Mail.  You can vote by mail by completing,
    signing, dating and mailing your proxy card or voting
    instruction card in the postage-paid envelope included with this
    joint proxy statement/prospectus.    FOR FOR FOR
   Voting of
    Shares Held in Street Name    AGAINST
   43




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AGAINST
 Revocability
    of Proxies; Changing Your Vote    
    by completing, signing, dating and returning a new proxy card
    with a later date so that it is received prior to the TGC
    special meeting;
    by calling the toll-free number listed on the proxy card or by
    accessing the Internet website listed on the proxy card by
    11:59 p.m. New York City time on [  ],
    2011; or
    by attending the TGC special meeting and voting by ballot in
    person at the TGC special meeting. 
   
   Solicitation
    of Proxies  out-of-pocket out-of-pocket
  TGC shareholders should not submit any stock certificates
    with their proxy cards.
 No Other
    Business   44




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Adjournments
    and Postponements       Assistance  (800) 967-4617 (212) 269-5550).
 45




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TGC
    PROPOSAL 1  APPROVAL OF THE MERGER
    AGREEMENT   
   
   
  The TGC board of directors recommends that TGC shareholders
    vote FOR approval of the merger agreement.
 46




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TGC
    PROPOSAL 2  NON-BINDING, ADVISORY VOTE ON
    APPROVAL OF CERTAIN COMPENSATION TO BE PAID BY TGC TO TGCS
    NAMED EXECUTIVE OFFICERS    
    the accelerated vesting of TGCs options to purchase shares
    of TGC common stock held by TGCs named executive officers
    beginning 30 days prior to the effective time of the merger
    and the right to receive the merger consideration in respect of
    any such options that are exercised prior to the effective time
    of the merger;
    the accelerated vesting of TGCs restricted stock held by
    TGCs named executive officers immediately prior to the
    effective time of the merger and the right to receive the merger
    consideration in respect of that restricted stock; and
    a cash bonus payment to be made to TGCs named executive
    officers upon the closing of the merger.    Pension/

Perquisites/

TaxCash

Equity

NQDC

Benefits

Reimbursement

Other

TotalName

($)

($)

($)

($)

($)

($)

($)Wayne A. Whitener


100,000
(1)


89,025
(4)


















189,025Daniel G. Winn


10,000
(2)


53,414
(5)


















63,414James K. Brata


8,000
(3)


82,693
(6)


















90,693     Footnotes:
  (1)
    
    Based on cash bonus payments due from TGC upon closing of the
    merger of $100,000.(2)
    
    Based on cash bonus payments due from TGC upon closing of the
    merger of $10,000.(3)
    
    Based on cash bonus payments due from TGC upon closing of the
    merger of $8,000.(4)
    
    Based on the accelerated vesting of stock options exercisable
    into 18,742 shares of common stock with an exercise price
    of $3.06 and using the assumed stock price of $7.81 based on the
    average of the closing price for the first five trading days
    after the announcement of the merger agreement as required
    pursuant to Item 402 of
    Regulation S-K.(5)
    
    Based on the accelerated vesting of stock options exercisable
    into 11,245 shares of common stock with an exercise price
    of $3.06 and using the assumed stock price of $7.81 based on the
    average of the closing price for the first five trading days
    after the announcement of the merger agreement as required
    pursuant to Item 402 of
    Regulation S-K.(6)
    
    Based on the accelerated vesting of stock options exercisable
    into 11,245 shares of common stock with an exercise price
    of $3.06 and using the assumed stock price of $7.81 based on the
    average of the closing price for the first five trading days
    after the announcement of the merger agreement as required
    pursuant to Item 402 of
    Regulation S-K
    and based on the accelerated vesting of 3,749 shares of
    restricted stock using the same $7.81 assumed stock price.  TGCs board of directors recommends its shareholders
    vote FOR the following resolution at the TGC special
    meeting:
  RESOLVED, that TGCs shareholders approve, on an
    advisory basis, the compensation that may be received by the TGC
    Industries, Inc.s named executive officers from TGC
    Industries, Inc. in connection with the merger as disclosed in
    the Proxy Statement of TGC Industries, Inc. concerning the
    merger under the heading Proposal 2 
    Non-Binding, Advisory Vote on Approval of Certain Compensation
    to be Paid by TGC to TGCs Named Executive
    Officers. 
 47




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48




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TGC
    PROPOSAL 3  ADJOURNMENT OF THE TGC SPECIAL
    MEETING    The TGC board of directors recommends that TGC shareholders
    vote FOR any adjournment of the TGC special meeting,
    if necessary or appropriate, to permit further solicitation of
    proxies.
 49




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THE
    PARTIES TO THE MERGER  Dawson Geophysical Company
 508 West Wall, Suite 800
 Midland, Texas 79701
 (432) 684-3000
  2-D, 3-D
  3-D
  2-D 3-D
   
   
  TGC Industries, Inc.
 101 East Park Blvd., Suite 955
 Plano, Texas 75074
 (972) 881-1099
  3-D
  land-to-water
  3-D
 50




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state-of-the-art 3-D
   
   
  6446 Acquisition Corp.
 508 West Wall, Suite 800
 Midland, Texas 79701
 (432) 684-3000
   51




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THE
    MERGER Overview    10-day
 
  Form 8-K
 
   Background
    of the Merger         52




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stock-for-stock
  stock-for-stock
       
   
 53




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stock-for-stock stock-for-stock
 
   
 
  stock-for-stock
 
  stock-for-stock
   54




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agreed-upon day-to-day
  stock-for-stock
   55




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stock-for-stock
       56




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go-shop,
            
    provisions relating to TGCs ability to provide
    information, have discussions or enter into an agreement with a
    third party that has made or makes a proposal to acquire TGC;
    provisions requiring TGC to hold a shareholder vote even if the
    TGC board of directors changes its recommendation regarding the
    merger (a force the vote provision);
    provisions of the voting agreement requiring TGCs
    directors and officers to vote in favor of the merger even if
    the TGC board changes its recommendation regarding the merger;
    whether the fairness opinion would be reaffirmed at closing as a
    condition to closing; and
    the circumstances under which a termination fee would be payable
    and the size of the fee. 57




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58




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59




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in-the-money
   
   
 
   
   Dawsons
    Reasons for the Merger and Recommendation of Dawsons Board
    of Directors   60




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FOR
    
    its knowledge of Dawsons business, operations, financial
    condition, earnings and prospects and of TGCs business,
    operations, financial condition, earnings and prospects, taking
    into account the results of Dawsons due diligence of TGC;
    its knowledge of the current environment in the seismic and
    energy industries, including the potential for continued
    consolidation or new entrants into the seismic market, current
    market and economic conditions and the likely effects of these
    factors on Dawsons and TGCs potential growth,
    development, productivity and strategic options;
    the fact that TGC has a demonstrated track record of growth and
    strong management and, following the merger, will continue to be
    operated as a separate, though wholly owned, operating entity
    that is managed by the same management team;
    the fact that Eagle Canada, Inc., TGCs Canadian operating
    subsidiary, has a demonstrated track record of growth and strong
    management and, following the merger, will continue to be
    managed by the same management team;
    the strategic nature of the acquisition, which would create a
    company which will have:  
    increased data acquisition crew capacity, with a combined crew
    count of 21 crews, as currently configured, in the continental
    United States and six in Canada, as well as combined channel
    counts in excess of 210,000 and more than 200 vibrator energy
    source units;
    a more diversified client mix, including increased geographical
    diversity and access to the Canadian market;
    expanded service offerings, including those leveraging
    TGCs dynamite source and shot-hole drilling capabilities;
    strong prospects for an expanded client base and product
    offering to allow for new business relationships not available
    to either company on a stand-alone basis;
    greater crew efficiencies gained through the ability to
    reconfigure crews, leverage and share equipment and personnel
    resources, including by leveraging Canadian resources during
    summer thaw periods;
    a continued balance of oil and natural gas projects and
    assignments, particularly in oil and liquid-rich basins;
    expanded support functions, including permit, survey,
    maintenance repair facilities and in-house trucking capabilities;
    better market position to meet client needs with an increased
    ability to service seismic projects in a timely manner and to
    provide higher resolution images with expanded channel counts,
    particularly with respect to unconventional reservoirs;
    increased opportunities to scale and align crew size with
    project size; and
    opportunities for cost savings and revenue generation through
    enhanced operational logistics;  
    the strong similarities in the corporate and operational
    cultures of the two companies; 61




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
    the fact that the companies have compatible equipment platforms
    and systems making the sharing of equipment and systems across
    the combined company easier and more efficient, thereby
    increasing the chance of a fast and successful integration;
    that the exchange ratio would enable Dawson shareholders to own
    approximately 68% of the outstanding common stock of Dawson
    following the merger;
    the fact that, based on the then recent closing prices of Dawson
    common stock on NASDAQ, the range within which the
    10-day
    average VWAP of Dawson common stock can fluctuate between the
    date of the merger agreement through [  ], 2011
    (which is the date that is two business days prior to the date
    of the special meetings) without requiring any renegotiation of
    the exchange ratio, is reasonable; 
  
    that TGC has generally agreed not to engage in negotiations
    with, or provide information to, a third party in connection any
    acquisition proposal or potential acquisition proposal unless
    (1) the TGC board of directors determines in good faith,
    after consultation with its legal and financial advisors, that
    such proposal constitutes or is reasonably likely to lead to a
    transaction that is more favorable to TGC shareholders from a
    financial point of view and is reasonably likely to be completed
    on the terms proposed, (2) TGC has not breached its
    non-solicitation covenants and (3) TGC enters into a
    confidentiality agreement with the third party; 
 
  
    the provisions of the merger agreement that allow Dawson, to
    engage in negotiations with, and provide information to, a third
    party that makes an unsolicited written acquisition proposal, if
    (1) the Dawson board of directors determines in good faith,
    after consultation with its legal and financial advisors, that
    such proposal constitutes or is reasonably likely to lead to a
    transaction that is more favorable to Dawson shareholders from a
    financial point of view and is reasonably likely to be completed
    on the terms proposed, (2) Dawson has not breached its
    non-solicitation covenants and (3) Dawson enters into a
    confidentiality agreement with the third party; 
 
  
    the provisions of the merger agreement that allow Dawson to
    change its recommendation that Dawson shareholders vote to
    approve the issuance of shares of Dawson common stock pursuant
    to the merger agreement or to terminate the merger agreement
    prior to its shareholder approval of the issuance of shares of
    Dawson common stock pursuant to the merger agreement, in order
    to enter into an alternative transaction in response to an
    unsolicited takeover proposal if (1) Dawsons board of
    directors determines in good faith, after consultation with
    outside counsel and financial advisors, that such proposal is
    more favorable to Dawson shareholders than the merger from a
    financial point of view, (2) Dawsons board of
    directors concludes that not changing its recommendation or
    terminating the merger agreement would constitute a breach of
    the Dawson directors fiduciary duties and (3) Dawson
    provides TGC with an opportunity to match the more favorable
    proposal; 
 
  
    the amount of the termination fee that Dawson would have to pay
    under the circumstances described on page 64 is low and
    therefore will likely not prevent interested parties from making
    a proposal for Dawson that could result in a superior proposal; 
 
  
    that TGC must pay to Dawson a termination fee of
    $2.35 million if (1) there is an acquisition proposal
    for TGC that is made public and subsequent to such announcement,
    (A) the merger does not close by the negotiated termination
    date, (B) TGC shareholders do not approve the merger, or
    (C) TGC breaches or fails to perform any of its
    representations and warranties or covenants and agreements
    and TGC enters into any acquisition proposal within one
    year of the termination of the merger agreement, (2) the
    TGC board changes or fails to reaffirm when requested, its
    recommendation that TGC shareholders approve the merger
    agreement or (3) TGC enters into a binding definitive
    agreement providing for a superior proposal; 
 
  
    that TGC must pay to Dawson a termination fee of
    $3.25 million in the event the merger agreement is
    terminated due to the failure of the reconfirmation opinion to
    be delivered; 
 
  
    the probability that the conditions to completion of the merger
    would be satisfied prior to the termination date of
    August 31, 2011 (October 31, 2011 if all conditions to
    the merger, other than 
 62




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(1) the termination or expiration of the waiting period
    under the HSR Act or (2) the absence of any judgment,
    injunction, order or decree in effect, or any law, statute, rule
    or regulation enacted, that prohibits the consummation of the
    merger, have been or are capable of being fulfilled); 
  
    the fact that directors and executive officers of TGC and their
    affiliates owned, as of March 20, 2011, in the aggregate,
    28.73% of the outstanding shares of TGC common stock agreed to
    enter into the TGC shareholder voting agreements with
    Dawson; and 
  
    Raymond James opinion, dated March 20, 2011, to
    Dawsons board as to the fairness from a financial point of
    view to Dawson, as of the date of the opinion, of the merger
    consideration to be paid by Dawson pursuant to the merger
    agreement and the related financial analyses, in each case as
    more fully described below in  Opinion of
    Dawsons Financial Advisor beginning on page 72. 
 
   
  
    the risks and contingencies relating to the announcement and
    pendency of the merger and the risks and costs to Dawson if the
    merger does not close timely or does not close at all, including
    the impact on Dawsons relationships with clients,
    employees and other third parties;
    the dilution to Dawson shareholders and the fact that the
    exchange ratio would enable TGC shareholders to own
    approximately 32% of the outstanding common stock of Dawson
    following the merger;
    the need to have at least 80% of the outstanding shares of TGC
    common stock vote in favor of approval of the merger agreement
    in order to consummate the merger and the possibility that TGC
    may be unable to obtain such approval;
    the risk of diverting management focus, employee attention and
    resources from other strategic opportunities and from
    operational matters while working to complete the merger and
    implement merger integration efforts;
    the challenges of combining the businesses, operations and
    workforces of Dawson and TGC and realizing the anticipated
    benefits of the merger;
    the risk that there is no assurance that all conditions to the
    parties obligations to complete the merger will be
    satisfied or waived, including HSR clearance, and as a result,
    it is possible that the merger could be delayed or might not be
    completed even if approved by each of the companys
    shareholders;
    Although TGC anticipated significant profitability for the
    quarter-ending March 31, 2011 (when compared to its
    quarterly results during fiscal year 2010), based on financial
    projections provided by TGC (which did not include the impact of
    transaction costs associated with the proposed merger), Dawson
    understood, based on such financial projections, that it was
    likely that TGCs profitability in the second, third and
    fourth quarters of fiscal year 2011 would be lower than its
    March quarter primarily due to the affects of seasonality,
    particularly the seasonal slowdown in Canada during warmer
    months, but that TGCs long-term prospects remained strong
    and that the combination of Dawson and TGC remained desirable.
    the transaction costs to be incurred in connection with the
    merger;
    the risk that new entrants may be attracted to the North
    American seismic market;
    the terms and conditions of the merger agreement, including:  
    the requirement that Dawson generally conduct its business only
    in the ordinary course and that Dawson is subject to a variety
    of other restrictions on the conduct of its business prior to
    the completion of the merger, any of which may delay or prevent
    Dawson from pursuing business opportunities that may arise or
    may delay or preclude Dawson from taking actions that would be
    advisable if it were to remain an independent company; 63




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
    that Dawson has agreed to not engage in negotiations with, or
    provide information to, a third party in connection with any
    acquisition proposal or potential acquisition proposal unless
    (1) the Dawson board of directors determines in good faith,
    after consultation with its legal and financial advisors, that
    such proposal constitutes or is reasonably likely to lead to a
    transaction that is more favorable to Dawson shareholders from a
    financial point of view and is reasonably likely to be completed
    on the terms proposed, (2) Dawson has not breached its
    non-solicitation covenants and (3) Dawson enters into a
    confidentiality agreement with the third party; 
 
  
    that TGC may engage in negotiations with, and provide
    information to, a third party that makes an unsolicited written
    acquisition proposal, if (1) the TGC board of directors
    determines in good faith, after consultation with its legal and
    financial advisors, that such proposal constitutes or is
    reasonably likely to lead to a transaction that is more
    favorable to TGC shareholders from a financial point of view and
    is reasonably likely to be completed on the terms proposed,
    (2) TGC has not breached its non-solicitation covenants and
    (3) TGC enters into a confidentiality agreement with the
    third party; 
 
  
    the provisions of the merger agreement that allow TGC to change
    its recommendation that TGC shareholders vote to approve the
    merger agreement or to terminate the merger agreement prior to
    its shareholder approval of the merger agreement, in order to
    enter into an alternative transaction in response to an
    unsolicited takeover proposal if (1) TGCs board of
    directors determines in good faith, after consultation with
    outside counsel and financial advisors, that such proposal is
    more favorable to TGC shareholders than the merger from a
    financial point of view, (2) TGCs board of directors
    concludes that not changing its recommendation or terminating
    the merger agreement would constitute a breach of the TGC
    directors fiduciary duties and (3) TGC provides
    Dawson with an opportunity to match the more favorable proposal; 
 
  
    the amount of the termination fee that TGC would have to pay
    under the circumstances described on page 62 is low and
    therefore will likely not prevent interested parties from making
    a proposal for TGC that could result in a superior
    proposal; and 
 
  
    that Dawson must pay to TGC a termination fee of
    $2.35 million if (1) there is an acquisition proposal
    for Dawson that is made public and subsequent to such
    announcement, (A) the merger does not close by the
    negotiated termination date, (B) Dawson shareholders do not
    approve the issuance of Dawson common stock to TGC shareholders
    in the merger, or (C) Dawson breaches or fails to perform
    any of its representations and warranties or covenants and
    agreements and Dawson enters into any acquisition
    proposal within one year of the termination of the merger
    agreement, (2) the Dawson board changes or fails to
    reaffirm when requested, its recommendation that Dawson
    shareholders approve the issuance of Dawson common stock to TGC
    shareholders in the merger or (3) Dawson enters into a
    binding definitive agreement providing for a superior
    proposal; and 
  
    the risks described in the section entitled Risk
    Factors beginning on page 24. 
   
     64




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Accordingly, the Dawson board of directors recommends that
    Dawson shareholders vote FOR approval of the
    issuance of shares of Dawson common stock pursuant to the merger
    agreement.
   TGCs
    Reasons for the Merger and Recommendation of TGCs Board of
    Directors    
    the aggregate value and the fact that the merger consideration
    to be received by TGC shareholders in the merger would be Dawson
    common stock;
    the fact that based on the following prices and the exchange
    ratio of 0.188 shares of Dawson common stock for each share
    of TGC common stock, TGCs shareholders will receive the
    following premiums: (1) for the
    20-day
    average prices of both Dawson and TGC ending on March 18,
    2011, 31.1%, (2) for the
    10-day
    average prices of both Dawson and TGC ending on March 18,
    2011, 22.5% and (3) for March 18, 2011, 17.1%;
    the fact that TGC does not have to close the merger if the
    10-day
    average VWAP of Dawson common stock as of [  ],
    2011 is less than $32.54;
    the fact that TGC will receive a legal opinion from Haynes and
    Boone, LLP at closing that the merger consideration will be
    received tax free by TGCs shareholders;
    the potential shareholder value that might result from other
    alternatives available to TGC, including the alternative of
    remaining as an independent public company, considering, in
    particular, the potential for TGCs shareholders to share
    in any future earnings growth of TGC and continued costs, risks
    and uncertainties associated with continuing to operate as a
    public company, including sharing the costs of being a public
    company;
    the TGC board of directors familiarity with, and
    understanding of, TGCs business, assets, financial
    condition, results of operations, current business strategy and
    prospects;
    information and discussions with TGCs management and
    Southwest Securities regarding Dawsons business, assets,
    financial condition, results of operations, business plan and
    prospects, including the size and scale of the combined company,
    especially the potential increased scale and scope of operations
    of the combined company;
    the complementary nature and geographic diversity of the assets
    of the companies;
    the fact that both TGC and Dawson expect the parties will
    receive clearance of the merger under the HSR Act;
    the operational and financial synergies of the two companies;
    due to the combination being structured as a
    stock-for-stock
    transaction, the complementary management styles and corporate
    cultures of the two companies, the fact that TGCs
    management would 65




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continue to manage TGC as a separate, though wholly owned,
    operating entity and would help strengthen the management of
    Dawson and the branding of Dawsons name and the fact that
    TGC shareholders would benefit from Dawsons strong
    management team;  
    the balance sheet strength and liquidity of the combined company;
    the analysis and fairness opinion of Southwest Securities
    delivered to the TGC board of directors;
    the fact that the acquisition would provide TGC with benefits of
    ownership in a larger company with a more diversified asset base
    and greater financial capacity;
    that because the merger consideration is payable in the form of
    Dawson common stock, TGCs shareholders would have the
    opportunity to participate in the equity value of the combined
    companies following the merger and would have the benefit of
    increased public market liquidity resulting from the combined
    companies larger public float and market cap due to the
    ownership of a larger public company. In that regard, the TGC
    board of directors understood that the volatility of prices for
    oil and natural gas and general stock market conditions would
    cause the value of the consideration received in the merger to
    fluctuate, perhaps significantly, following the closing of the
    merger, but was of the view that on a long-term basis it would
    be desirable for shareholders to have an opportunity to retain a
    continuing investment in the combined companies following the
    merger;
    the TGC board of directors understanding of and
    managements review of overall market conditions, including
    then-current and prospective commodity prices and the current
    and historical trading prices for each of the companys
    common stock, and TGCs board of directors
    determination that, in light of these factors, the timing of the
    potential transaction was favorable to TGC;
    the fact that although the TGC board of directors did not
    conduct an auction process or other effort to solicit interest
    from other potential buyers prior to the execution and delivery
    of the merger agreement, the TGC board of directors felt that it
    should enter into the merger agreement without including a
    go-shop provision for several reasons, including, (1) the
    unique business opportunity offered by this deal since it is a
    stock-for-stock
    deal with a company in the same industry; (2) since despite
    numerous requests for a go-shop provision by TGC, Dawson would
    not permit a go-shop provision, TGC was able to negotiate a low
    termination fee in order to not preclude any potential superior
    proposals and TGC will be able pay the low termination fee and a
    capped expense fee if a superior proposal is made; and
    (3) Southwest Securities will review any future proposals
    to help determine if they are superior proposals;
    the review by TGCs board of directors with its legal and
    financial advisors of the structure of the merger and the
    financial and other terms of the merger agreement, including the
    parties representations, warranties and covenants, the
    conditions to their respective obligations and the termination
    provisions, as well as the likelihood of consummation of the
    merger and TGCs board of directors evaluation of the
    likely time period necessary to close the merger. TGCs
    board of directors also considered the following specific
    aspects of the merger agreement:  
    the nature of the closing conditions included in the merger
    agreement, including the market, industry-related and other
    exceptions to the events that would constitute a material
    adverse effect on either TGC or Dawson for purposes of the
    agreement, as well as the likelihood of satisfaction of all
    conditions to the consummation of the merger;
    TGCs right to engage in negotiations with, and provide
    information to, a third party that makes an unsolicited written
    acquisition proposal, if the TGC board of directors determines
    in good faith, after consultation with its legal and financial
    advisors, that such proposal constitutes or is reasonably likely
    to lead to a transaction that is more favorable to the
    shareholders than the merger from a financial point of view and
    is reasonably likely to be completed on the terms proposed,
    taking into account all financial, legal, regulatory and other
    aspects of such proposal; 
  
    TGCs right both to change its recommendation to vote in
    favor of the merger
    and/or
    terminate the merger agreement in order to accept a superior
    proposal if (1) TGCs board of directors determines 
 66




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in good faith, after consultation with outside counsel and
    financial advisors, that such proposal is more favorable to TGC
    shareholders than the merger from a financial point of view,
    (2) TGCs board of directors concludes that not
    changing its recommendation or terminating the merger agreement
    would constitute a breach of the Dawson directors
    fiduciary duties and (3) TGC provides Dawson with an
    opportunity to match the more favorable proposal; 
 
  
    the amount of the termination fee that TGC would have to pay
    under the circumstances described on page 62 is low and
    should not prevent interested parties from making a proposal
    that could result in a superior proposal; 
 
  
    the obligation of Dawson to pay to TGC a termination fee if
    (1) there is an acquisition proposal for Dawson that is
    made public by a third party and subsequent to such
    announcement, (A) the merger does not close by the
    negotiated termination date, (B) Dawson shareholders do not
    approve the issuance of Dawson common stock to TGC shareholders,
    or (C) Dawson breaches or fails to perform any of its
    representations and warranties or covenants and agreement
    and Dawson enters into any acquisition proposal within
    one year of the termination of the merger agreement,
    (2) the Dawson board changes or fails to reaffirm when
    requested, its recommendation that Dawson shareholders approve
    the issuance of Dawson common stock to TGC shareholders or
    (3) Dawson enters into a binding definitive agreement
    providing for a superior proposal and to reimburse
    out-of-pocket
    expenses under the circumstances specified in the merger
    agreement; 
 
  
    the ability to terminate the transaction if the reconfirmation
    opinion fails to confirm, as of the closing date, that the
    exchange ratio is fair, from a financial point of view, to TGC
    shareholders; and 
  
    certain other provisions in the merger agreement, including the
    termination provisions.    
    the risks and contingencies relating to the announcement and
    pendency of the merger and the risks and costs to TGC if the
    closing of the merger is not timely or if the merger does not
    close at all, including the diversion of management and employee
    attention, potential employee attrition, the impact on
    TGCs relationships with third parties and the effect a
    public announcement of termination of the merger agreement may
    have on the trading price of the TGCs common stock and
    operating results;
    the fact that the price of the stock of the acquiring company in
    stock-for-stock
    mergers often drops after the announcement of a merger;
    the volatility of the price of both stocks could cause the
    premium to be received by TGCs shareholders to be less
    than the
    20-day
    average prices of both Dawson and TGC,
    10-day
    average prices of both Dawson and TGC and spot price premiums of
    31.1%, 22.5% and 17.1%, respectively, that existed on
    March 18, 2011;
    although TGC anticipated profitability for the quarter-ending
    March 31, 2011, based on financial projections provided by
    Dawson (which did not take into account transaction expenses
    relating to the proposed merger), TGC understood that it was
    likely Dawson would incur a significant pre-tax loss for the
    quarter-ending March 31, 2011 due primarily to reduced crew
    activity and productivity and an increased level of equipment
    damage as a result of the ongoing harsh weather conditions in
    the regions in which Dawson operated during the quarter, though
    the TGC board of directors understood, based on such financial
    projections provided by Dawson, which indicated that Dawson
    would return to significant profitability in the quarters ending
    June 30, 2011 and September 30, 2011 (though not at
    the level experienced by Dawson prior to the economic downturn
    in the United States) that Dawsons
    long-term
    prospects remained strong and that the addition and integration
    of TGC operations and management would further enhance the
    combined operating results;
    the fact that Dawson does not have to close the merger if the
    10-day
    average VWAP of Dawson common stock as of [  ]
    is less than $32.54 or greater than $52.54; 67




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##### Table of Contents




    the fact that TGCs obligation to close the merger is
    conditioned on a supermajority vote of its shareholders;
    the fact that there is no assurance that all conditions to the
    parties obligations to complete the merger will be
    satisfied or waived, including HSR clearance, and as a result,
    it is possible that the merger might not be completed even if
    approved by each of the companys shareholders; 
  
    under the terms of the merger agreement, TGC will be required to
    pay to Dawson a termination fee of $2.35 million and to
    reimburse Dawson for expenses if (1) there is an
    acquisition proposal for TGC that is made public and subsequent
    to such announcement, (A) the merger does not close by the
    negotiated termination date, (B) TGC shareholders do not
    approve the merger, or (C) TGC breaches or fails to perform
    any of its representations and warranties or covenants and
    agreements and TGC enters into any acquisition proposal
    within one year of the termination of the merger agreement,
    (2) the TGC board changes or fails to reaffirm when
    requested, its recommendation that TGC shareholders approve the
    merger agreement or (3) TGC enters into a binding
    definitive agreement providing for a superior proposal; 
 
  
    under the terms of the merger agreement, TGC will be required to
    pay to Dawson a termination fee of $3.25 million and to
    reimburse Dawson for expenses in the event the merger agreement
    is terminated due to the failure of the reconfirmation opinion
    to be delivered; 
  
    the transaction costs to be incurred in connection with the
    merger; 
  
    the interests that some of TGCs directors and executive
    officers may have interests in the transactions contemplated by
    the merger agreement that may be different from, or in addition
    to, their interests as TGC shareholders and the interests of TGC
    shareholders generally, as described in
     Conflicts of Interests beginning on
    page 89; 
  
    the restrictions on the conduct of TGCs business prior to
    completion of the merger, requiring TGC to conduct its business
    only in the ordinary course, subject to specific limitations,
    including limitations of capital expenditures, which may delay
    or prevent TGC from undertaking business opportunities that may
    arise pending completion of the merger;
    the potential of negative reaction by the market to the merger
    based on the business rationale for the merger, the timing of
    the merger and the terms of the merger;
    the limited industry or business line diversification;
    the business execution and integration risk after the merger is
    closed; and
    client reaction to the transaction.    Accordingly, the TGC board of directors recommends that TGC
    shareholders vote FOR approval of the merger
    agreement.
   
   
 
 Certain
    Information Provided by the Parties   
 68




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##### Table of Contents



Dawson
    Unaudited Prospective Financial Information
 
 
   
 
   
 
   
 
   
 
   
 69




---



##### Table of Contents



The inclusion of this
    information should not be regarded as an indication that this
    information is a reliable prediction of future events, and this
    information should not be relied upon as such.
 
 
   
 
   
 
   
 
  Dawson
    Geophysical Company
    Unaudited Prospective Financial Information
 
  
 Projected Calendar Year Ended December
    31,1($ in millions)

2011


2012


2013


2014


2015Operating revenue

$
324.9


$
339.7


$
383.2


$
387.1


$
390.9Income before income taxes


11.2



29.4



38.0



34.1



28.5Net income


7.7



20.1



26.1



23.4



19.5EBITDA


41.4



61.2



72.1



72.8



73.6  
  
 Projected Calendar Quarter EndedMarch 31,


June 30,


September 30,


December 31,($ in millions)

2011


2011


2011


2011Operating revenueIncome before income taxesNet income (loss)EBITDA  
   
  1

    
    The annual financial information presented in the first table
    was prepared on a calendar year basis at the request of TGC.
    Dawsons actual fiscal year ends on September 30. 
 
  TGC
    Unaudited Prospective Financial Information
 
 
   
 70




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##### Table of Contents



The inclusion of this information should
    not be regarded as an indication that this information is a
    reliable prediction of future events, and this information
    should not be relied upon as such.
 
 
   
 
   
 71




---



##### Table of Contents



TGC
    Industries, Inc.
    Unaudited Prospective Financial Information
 
  
 Projected Fiscal Year Ended December 31,($ in millions)

2011


2012


2013


2014


2015Total revenue

$
132.7


$
159.8


$
167.2


$
175.1


$
183.3Pre-tax income


8.6



17.8



20.9



23.6



25.5Net income (loss)


5.6



10.7



12.6



14.2



15.3EBITDA


25.2



34.3



36.3



38.4



40.2  
  
 Projected Calendar Quarter EndedMarch 31,


June 30,


September 30,


December 31,($ in millions)

2011


2011


2011


2011Total revenuePre-tax incomeNet income (loss)EBITDA  
 Opinion
    of Dawsons Financial Advisor     
  The full text of the written opinion of Raymond James, dated
    March 20, 2011, is attached as Annex B to this joint
    proxy statement/prospectus. The summary of the opinion of
    Raymond James set forth in this joint proxy statement/prospectus
    is qualified in its entirety by reference to the full text of
    such opinion. Raymond James has consented to the inclusion of
    its opinion in this joint proxy statement/prospectus.
 
  Holders of Dawson common stock are urged to read this opinion
    in its entirety. Raymond Jamess opinion, which is
    addressed to the Dawson board of directors, is directed only to
    the fairness, from a financial point of view, of the merger
    consideration to be paid by Dawson pursuant to the merger
    agreement. Raymond Jamess opinion does not constitute a
    recommendation to any holder of Dawson common stock as to how
    such shareholder should vote at the special meeting of Dawson
    shareholders and does not address any other aspect of the
    proposed merger or any related transaction. Raymond James does
    not express any opinion as to the likely trading range of Dawson
    common stock following the merger, which may vary depending on
    numerous factors that generally impact the price of securities
    or on the financial condition of Dawson at that time.
 72




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##### Table of Contents




    reviewed the merger agreement, including the financial terms and
    conditions;
    reviewed Annual Reports on
    Form 10-K
    and related audited financial statements of Dawson as of and for
    the fiscal years ended September 30, 2010, 2009 and 2008
    and TGC as of and for the fiscal years ended December 31,
    2010, 2009 and 2008;
    reviewed other financial and operating information requested
    from and/or
    provided by Dawson and TGC;
    reviewed certain other publicly available business and financial
    information on Dawson and TGC;
    discussed with members of the senior management of each of
    Dawson and TGC past and current business, operations, financial
    information and any other matters which it deemed relevant;
    discussed the current and projected operations and prospects of
    Dawson and TGC with senior management of both Dawson and TGC;
    reviewed the historical market prices and trading history of
    Dawson and TGC;
    compared financial and stock market information for Dawson and
    TGC with similar information for comparable companies with
    publicly traded equity securities;
    compared the financial terms of the merger with financial terms
    of other transactions that it deemed to be relevant; and
    performed other such analyses, and considered such other
    information and factors, as it considered relevant and
    appropriate.     73




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##### Table of Contents



Trading Analysis.
  Price per

ImpliedShare

PremiumMerger consideration value

$
8.00



TGC closing common stock price as of 3/18/2011


6.83



17.1
%52-week high TGC common stock price (3/9/2011)


7.25



10.3
%52-week low TGC common stock price (7/6/2010)


2.92



174.0
%   Selected Public Companies Analysis.
  
    CGG Veritas;
    Global Geophysical Services, Inc.;
    Geokinetics Inc.;
    ION Geophysical Corporation;
    Mitcham Industries, Inc.; and
    OYO Geospace Corporation   74




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##### Table of Contents



Enterprise Value/EBITDATTM

CY11E

CY12EMinimum


5.1
x


3.4
x


3.0
xMedian


16.5
x


6.1
x


5.0
xMean


16.1
x


6.7
x


5.6
xMaximum


28.2
x


12.3
x


10.3
xMerger consideration


10.1
x


6.2
x


4.6
x     Enterprise Value/EBITDATTM

CY11E

CY12EMinimum

$
3.98


$
4.29


$
5.26Median


12.98



7.86



8.68Maximum


22.25



15.81



18.08Merger consideration

$
8.00


$
8.00


$
8.00     Acquirer

TargetSeawell Limited

Gray Wireline Service, Inc.Seawell Limited

Allis-Chalmers Energy Inc.Nabors Industries Ltd.

Superior Well Services Inc.Key Energy Services, Inc.

OFS Energy Services, LLCPatterson-UTI Energy, Inc.

Key Energy Services, Inc.Wellspring Capital Management LLC

Omni Energy Services Corp.Halliburton Company

Boots & Coots, Inc.Geokinetics Inc.

Petroleum Geo-ServicesCameron International Corp.

NATCO Group Inc.Insituform Technologies Inc.

The Bayou Companies LLCValueAct Capital

Seitel, Inc.Cal Dive International, Inc.

Horizon Offshore, Inc.Geokinetics, Inc.

Grant Geophysical, Inc.Compagnie Générale de Géophysique SA

Veritas DGC Incorporated    75




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##### Table of Contents



EnterpriseEnterprise Value/

Implied

Value/

ImpliedLast 12 Months

Equity Price

Forward

Equity PriceEBITDA

per Share

EBITDA

per ShareMinimum


4.5
x

$
3.50



3.9
x

$
4.94Median


8.1
x


6.41



5.4
x


6.93Maximum


20.1
x


15.85



10.5
x


13.53Merger consideration


10.1
x

$
8.00



6.2
x

$
8.00   Transaction Premium Analysis.
  Implied Premium1-Day

1-Week

1-MonthMinimum


1.5%



3.2%



(7.5)%Median


20.4%



21.8%



22.1%Mean


20.7%



24.0%



24.0%Maximum


37.5%



51.4%



62.3%Merger consideration

$
8.00


$
8.00


$
8.00TGC closing common stock price per share

$
6.83


$
6.88


$
5.80Implied Transaction premium


17.1%



16.3%



37.9%     Implied Equity Price per Share1-Day

1-Week

1-MonthMinimum

$
6.93


$
7.10


$
5.37Median


8.22



8.38



7.08Maximum


9.39



10.41



9.41Merger consideration

$
8.00


$
8.00


$
8.00   Discounted Cash Flow Analysis.
   76




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##### Table of Contents



Equity Valueper ShareMinimum

$
7.31Maximum

$
10.86Merger consideration

$
8.00   Contribution Analysis.
  TGC

DawsonChannel Count (as of December 31, 2010)


39
%


61
%TTM revenue


31
%


69
%CY11E revenue


29
%


71
%CY12E revenue


32
%


68
%TTM EBITDA


48
%


52
%CY11E EBITDA


38
%


62
%CY12E EBITDA


36
%


64
%Ownership at effective time of the merger


32
%


68
%   Additional Considerations.
 
   
 77




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##### Table of Contents



Opinion
    of TGCs Financial Advisor   
   
  
    reviewed the merger agreement;
    reviewed and analyzed certain publicly available financial and
    other data with respect to TGC and Dawson and certain other
    relevant historical operating data relating to TGC and Dawson
    made available to it from published sources and from the
    internal records of TGC and Dawson;
    conducted discussions with members of the senior management of
    TGC and Dawson with respect to the business prospects and
    financial outlook of TGC and Dawson;
    visited the business offices of TGC and Dawson;
    reviewed current and historical market prices and trading
    activity of the common stock of TGC and Dawson; 78




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##### Table of Contents




    compared certain financial information for TGC and Dawson with
    similar information for certain other companies, the securities
    of which are publicly traded;
    reviewed the financial terms, to the extent publicly available,
    of selected precedent transactions which it deemed generally
    comparable to TGC and the merger; and
    conducted such other financial studies, analyses and
    investigations and considered such other information as it
    deemed appropriate.     
   
   79




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##### Table of Contents



Summary
    of Southwest Securities Analyses
 
   
 
   
    Historical Market Trading Exchange Ratio
    Analysis.
  
    the ratio of the closing price of TGC common shares divided by
    the closing price of Dawson common shares on March 18,
    2011, and
    the ratio of the average closing prices of TGC common shares
    divided by average closing prices of Dawson common shares
    computed over various periods ended March 18, 2011.  80




---



##### Table of Contents



ImpliedExchangeRatioAs of March 18, 2011


0.161
x30-Day
    Average


0.140
x60-Day
    Average


0.137
x90-Day
    Average


0.131
xOne Year Average


0.138
xTwo Year Average


0.146
xThree Year Average


0.136
x     Comparable Company Analysis.
  Geophysical Companies

North American Oilfield Service Companies   Compagnie Générale de
    Géophysique-Veritas

   Core Laboratories N.V.   Petroleum Geo-Services ASA

   Superior Energy Services, Inc.   ION Geophysical Corporation

   Key Energy Services, Inc.   OYO Geospace Corporation

   Complete Production Services, Inc.   Global Geophysical Services, Inc.

   RPC, Inc.   Dawson Geophysical Company

   TETRA Technologies, Inc.   Geokinetics Inc.

   Basic Energy Services, Inc.   Bolt Technology Corporation   Mitcham Industries, Inc.   Tesla Exploration Ltd.   and/or
   81




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##### Table of Contents



Enterprise Value/EBITDA2010

2011E

2012EGeophysical Companies:High


17.7
x


11.0
x


8.3
xMean


9.9
x


6.7
x


5.2
xMedian


8.7
x


6.9
x


5.6
xLow


4.5
x


3.4
x


3.0
xNorth American Oilfield Service Companies  Group
    Median


9.0
x


6.5
x


5.6
xTGC at Implied Transaction Value:Wall Street Research Consensus Estimates (2011 and 2012)


10.1
x


6.3
x


3.7
xManagement Forecast Estimates (2011 and 2012)


10.1
x


6.2
x


4.6
x     Low



HighActual 2010 EBITDA


7.5
x






9.0
xWall Street Research Consensus Estimate of 2011 EBITDA


5.5
x






7.5
xWall Street Research Consensus Estimate of 2012 EBITDA


3.5
x






5.5
xManagement Forecast Estimate of 2011 EBITDA


5.5
x






7.5
xManagement Forecast Estimate of 2012 EBITDA


3.5
x






5.5
x   Implied Exchange

Proposed ExchangeRatio Reference Range

Ratio0.157x  0.224x


0.188x    82




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##### Table of Contents



Selected Precedent Transactions
    Analysis.
  DateAnnounced

Acquirer

Target11/08/10

Heckmann Corporation

Complete Vacuum and Rental, Inc.10/06/10

Robbins & Myers, Inc.

T-3 Energy Services, Inc.08/12/10

Seawell Limited

Allis-Chalmers Energy Inc.08/06/10

Nabors Industries Ltd.

Superior Well Services, Inc.07/23/10

Key Energy Services, Inc.

Davis Energy; QCP; Swan Energy06/03/10

Wellspring Capital Management LLC

OMNI Energy Services Corp.04/09/10

Halliburton Company

Boots & Coots, Inc.12/03/09

Geokinetics Inc.

Petroleum Geo-Services  Onshore Assets08/30/09

Baker Hughes Incorporated

BJ Services Company06/08/08

Precision Drilling Corporation

Grey Wolf, Inc.06/03/08

Smith International, Inc.

W-H Energy Services, Inc.12/17/07

National Oilwell Varco, Inc.

Grant Prideco, Inc.01/08/07

Basic Energy Services, Inc.

JetStar Energy Services, Inc.11/01/06

ValueAct Capital, LLC

Seitel, Inc.10/26/06

Allis-Chalmers Energy Inc.

Oil & Gas Rental Services09/22/06

Superior Energy Services, Inc.

Warrior Energy Services Corporation09/05/06

Compagnie Générale de Géophysique

Veritas DGC Inc.     Enterprise Value/LTM EBITDA

Peak EBITDAHigh


18.7
x


7.4
xMean


8.8
x


5.0
xMedian


7.6
x


4.5
xLow


4.7
x


2.7
x     Implied Exchange

Proposed ExchangeRatio Reference Range

Ratio0.094x  0.203x


0.188x    83




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##### Table of Contents



Discounted
    Cash Flow Analysis
    
    the estimated future cash flow that the company is projected to
    generate for the period of March 31, 2011 through
    December 31, 2015, and
    the estimated value of the company at the end of such period, or
    terminal value.    Implied Exchange

Proposed ExchangeRatio Reference Range

Ratio0.129x  0.284x


0.188x   Premia
    Paid Analysis
   84




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##### Table of Contents



Share Price PremiumDays Prior to Offer Date1 Day

1 Week

1 MonthAll Energy Transactions(1):High(2)


34.8
%


37.9
%


42.4
%Mean


24.6
%


25.9
%


28.7
%Median


21.5
%


23.1
%


28.1
%Low(3)


13.1
%


14.6
%


15.4
%Oilfield Service Company Transactions:High(2)


33.8
%


45.1
%


45.0
%Mean


29.5
%


31.1
%


34.3
%Median


20.0
%


24.2
%


31.1
%Low(3)


16.4
%


16.4
%


26.6
%Energy
    Stock-for-Stock
    Transactions:High(2)


27.5
%


29.2
%


35.0
%Mean


17.6
%


22.4
%


25.1
%Median


18.1
%


25.4
%


21.2
%Low(3)


7.7
%


16.7
%


14.0
%     (1)
    
    Energy transactions include exploration and production, oilfield
    service and midstream companies.(2)
    
    Represents the
    75th

    percentile.(3)
    
    Represents the
    25th

    percentile.    Implied Exchange

Proposed ExchangeRatio Reference Range

Ratio0.174x  0.205x


0.188x   Relative
    Contribution Analysis
  (2006-2010),
  
    EBITDA
    Net income
    Cash flow from operations   85




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##### Table of Contents



Implied Exchange RatioCash FlowEBITDA

Net Income

From Operations5-Year
    Average (2006  2010)


0.194
x


0.180
x


0.263
x2010 Actual


0.307
x


NM
(1)


0.242
x2011 (Wall Street Research Consensus Estimate)


0.233
x


0.544
x


NA2011(Management Forecast Estimate)


0.218
x


0.299
x


0.252
x2012 (Wall Street Research Consensus Estimate)


0.296
x


0.373
x


NA2012 (Management Forecast Estimate)


0.201
x


0.245
x


0.203
x     (1)
    
    Not meaningful due to net losses reported by TGC and Dawson in
    2010.    Implied Exchange

Proposed ExchangeRatio Reference Range

Ratio0.200x  0.300x


0.188x  
   
  Additional Considerations.
   Stock
    Ownership of Directors and Executive Officers of Dawson and
    TGC  Dawson
   86




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##### Table of Contents



TGC
 
   
 
  Form 10-K/A
 
 Merger
    Consideration  10-day
 
  10-day
 
  The Wall Street
    Journal
  The
    number of shares of Dawson common stock to be issued in the
    merger for each share of TGC common stock is
    fixed.
  10-day
   87




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##### Table of Contents



Implied Value ofOne Share ofDawson Common Stock

TGC Common Stock

TGC Common StockMarch 18, 2011

$
42.54


$
6.83


$
8.00[  ], 2011


[  ]



[  ]



[  ]  
  10-day
 
 
   
 
   
 Accounting
    Treatment     Listing
    of Dawson Common Stock and Delisting and Deregistration of TGC
    Common Stock   88




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##### Table of Contents



Restrictions
    on Sales of Shares of Dawson Common Stock Received in the
    Merger   Opinions
    as to Material U.S. Federal Income Tax Consequences of the
    Merger     Ownership
    of Dawson Following the Merger   Board of
    Directors and Management of Dawson Following the
    Merger       
 Conflicts
    of Interests   
 89




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##### Table of Contents



Treatment
    of Equity Awards
  Stock Options.
   
  Restricted Stock.
 
 
   
  Stock Options

Restricted StockNumber ofShares



Number ofUnderlying



Unvested Shares

Value of SharesUnexercised

Exercise Price

of Restricted

of RestrictedName

Options

($)

Stock

StockAllen T. McInnes


10,989


$
8.38







Allen T. McInnes


24,320



3.09







Allen T. McInnes


19,936



3.88







William J. Barrett


10,989



8.38







William J. Barrett


24,320



3.09







William J. Barrett


19,936



3.88







Herbert M. Gardner


10,989



8.38







Herbert M. Gardner


24,320



3.09







Herbert M. Gardner


19,936



3.88







Edward L. Flynn


10,989



8.38







Edward L. Flynn


24,320



3.09







Edward L. Flynn


19,936



3.88







Stephanie P. Hurtt


10,989



8.38







Stephanie P. Hurtt


24,320



3.09







Stephanie P. Hurtt


19,936



3.88







Wayne A. Whitener


55,125



3.06







Daniel G. Winn


33,075



3.06







James K. Brata


33,075



3.06



3,749


$
22,682
(1)    
  (1)
    
    Calculated based upon the closing price of TGCs common
    stock on July 11, 2011. 
   90




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##### Table of Contents



Future
    Employment by Dawson
     
   
 
   
  Indemnification
    and Insurance
         91




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##### Table of Contents



Golden
    Parachute Compensation
 
   
    
    the accelerated vesting of TGCs options to purchase shares
    of TGC common stock held by TGCs named executive officers
    beginning 30 days prior to the effective time of the merger
    and the right to receive the merger consideration in respect of
    any shares issued upon exercise of such options prior to the
    effective time of the merger;
    the accelerated vesting of TGCs restricted stock held by
    TGCs named executive officers immediately prior to the
    effective time of the merger and the right to receive the merger
    consideration in respect of that restricted stock;
    a cash bonus payment to be made to TGCs named executive
    officers upon the closing of the merger ; 
  
    annual salaries and other compensation payable pursuant to
    employment agreements of TGCs named executive officers
    with TGC, as the surviving entity of the merger, to be entered
    into upon the closing of the merger (see The
    Merger  Conflicts of Interests  Future
    Employment by Dawson and The Employment
    Agreements  Description of Specific Employment
    Agreements beginning on pages 91 and 124,
    respectively); 
 
  
    the annual salary and other compensation payable pursuant to the
    employment agreement of Mr. Jumper with Dawson to be
    entered into upon the closing of the merger (see The
    Employment Agreements  Description of Specific
    Employment Agreements beginning on page 124); and 
  
    grants of 6,000, 3,000 and 3,000 shares of restricted
    Dawson common stock to each of Messrs. Whitener, Winn and
    Brata, respectively, which grants of restricted stock will be
    awarded as of the effective date of the merger only if the
    merger is completed and, if awarded, will vest on the third
    anniversary of the date of grant.   92




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Regulation S-K.
  GOLDEN
    PARACHUTE COMPENSATION TABLE
  Pension/

Perquisites/

TaxCash

Equity

NQDC

Benefits

Reimbursement

Other

TotalName

($)

($)

($)

($)

($)

($)

($)Wayne A. Whitener


1,000,000
(1)


349,425
(5)






29,700(8
)










1,379,125Daniel G. Winn


589,000
(2)


183,614
(6)






27,900(8
)










800,514James K. Brata


548,000
(3)


212,893
(7)






26,100(8
)










786,993Stephen C. Jumper


1,155,000
(4)










29,700(8
)










1,184,700     Footnotes:
  (1)
    
    Based on cash bonus payments due from TGC upon closing of the
    merger of $100,000 and a three year employment agreement with an
    annual base salary of $300,000.(2)
    
    Based on cash bonus payments due from TGC upon closing of the
    merger of $10,000 and a three year employment agreement with an
    annual base salary of $193,000.(3)
    
    Based on cash bonus payments due from TGC upon closing of the
    merger of $8,000 and a three year employment agreement with an
    annual base salary of $180,000.(4)
    
    Based on a three year employment agreement with an annual base
    salary of $385,000.(5)
    
    Based on (A) the accelerated vesting of stock options
    exercisable into 18,742 shares of common stock with an
    exercise price of $3.06 and using the assumed stock price of
    $7.81 based on the average of the closing price for the first
    five trading days after the announcement of the merger agreement
    as required pursuant to Item 402 of
    Regulation S-K
    and (B) a conditional grant of 6,000 shares of Dawson
    restricted common stock, using an assumed value of $43.40 per
    share based on the average of the closing price of Dawson common
    stock for the first five trading days after the announcement of
    the merger agreement as required pursuant to Item 402 of
    Regulation S-K,
    which shares of Dawson restricted common stock shall only be
    granted in the event the merger is completed.(6)
    
    Based on (A) the accelerated vesting of stock options
    exercisable into 11,245 shares of common stock with an
    exercise price of $3.06 and using the assumed stock price of
    $7.81 based on the average of the closing price for the first
    five trading days after the announcement of the merger agreement
    as required pursuant to Item 402 of
    Regulation S-K
    and (B) a conditional grant of 3,000 shares of Dawson
    restricted common stock, using an assumed value of $43.40 per
    share based on the average of the closing price of Dawson common
    stock for the first five trading days after the announcement of
    the merger agreement as required pursuant to Item 402 of
    Regulation S-K,
    which shares of Dawson restricted common stock shall only be
    granted in the event the merger is completed.(7)
    
    Based on (A) the accelerated vesting of stock options
    exercisable into 11,245 shares of common stock with an
    exercise price of $3.06 and using the assumed stock price of
    $7.81 based on the average of the closing price for the first
    five trading days after the announcement of the merger agreement
    as required pursuant to Item 402 of
    Regulation S-K,
    (B) the accelerated vesting of 3,749 shares of
    restricted stock using the same $7.81 assumed stock price and
    (C) a conditional grant of 3,000 shares of Dawson
    restricted common stock, using an assumed value of $43.40 per
    share based on the average of the closing price of Dawson common
    stock for the first five trading days after the announcement of
    the merger agreement as required 93




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pursuant to Item 402 of
    Regulation S-K,
    which shares of Dawson restricted common stock shall only be
    granted in the event the merger is completed.(8)
    
    Based on the estimated three year cost of providing a vehicle,
    fuel, insurance, maintenance, repair and other reasonable costs.    Other
    Benefit Arrangements
    day-to-day
 Appraisal
    Rights   Regulatory
    Requirements  30-day
 
   
 94




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Dividend
    Policy   95




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THE
    MERGER AGREEMENT  The following summary describes the material provisions of
    the merger agreement. The provisions of the merger agreement are
    complicated and not easily summarized. This summary may not
    contain all of the information about the merger agreement that
    is important to you. This summary is qualified in its entirety
    by reference to the merger agreement attached as Annex A
    to, and incorporated by reference into, this joint proxy
    statement/prospectus. We encourage you to read it carefully in
    its entirety for a more complete understanding of the merger
    agreement.
  The merger agreement has been included to provide you with
    information regarding its terms and the transactions described
    in this joint proxy statement/prospectus. Neither Dawson nor TGC
    intends that the merger agreement will be a source of business
    or operational information about Dawson or TGC. The merger
    agreement contains representations and warranties that Dawson
    and TGC have made to each other. Those representations and
    warranties are qualified in several important respects, which
    you should consider as you read them in the merger agreement. In
    particular, in your review of the representations and
    warranties, it is important to bear in mind that the
    representations and warranties were made solely for the benefit
    of the parties to the merger agreement and were negotiated for
    the purpose of allocating contractual risk among the parties
    rather than to establish matters as facts. The representations
    and warranties may also be subject to a contractual standard of
    materiality or material adverse effect different from those
    generally applicable to shareholders and reports and documents
    filed with the SEC and in some cases may be qualified by
    disclosures made by one party to the other, which are not
    necessarily reflected in the merger agreement. Moreover,
    information concerning the subject matter of the representations
    and warranties, which do not purport to be accurate as of the
    date of this joint proxy statement/prospectus, may have changed
    since the date of the merger agreement, and subsequent
    developments or new information qualifying a representation or
    warranty may have been included in or incorporated by reference
    into this joint proxy statement/prospectus. Dawson and TGC will
    provide additional disclosure in their public reports of any
    material information necessary to provide their respective
    shareholders with a materially complete understanding of the
    disclosures relating to the merger agreement.
 
  For the foregoing reasons, the representations and warranties
    should not be read alone or relied upon as characterizations of
    the actual state of facts or condition of Dawson, Merger Sub,
    TGC or any of their respective subsidiaries or affiliates.
    Instead, such provisions or descriptions should be read only in
    conjunction with the other information provided elsewhere in, or
    incorporated by reference into, this joint proxy
    statement/prospectus. See Where You Can Find More
    Information beginning on page 150.
 
 Merger   Effective
    Time; Closing   
     96




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Governance
    Matters   Merger
    Consideration  10-day
      Determination
    of the Exchange Ratio
  10-day 10-day
  10-day
  10-day
 97




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Fractional
    Shares
  The Wall Street
    Journal
  Adjustment
    of the Merger Consideration
   Effect of
    the Merger on TGCs Equity Awards  TGC
    Stock Options
  30-day 30-day
    
    each such converted stock option will be exercisable for a
    number of shares of Dawson common stock equal to the product
    (rounded down to the nearest whole share) of (1) the number
    of shares of TGC common stock subject to such stock option
    immediately prior to the effective time of the merger multiplied
    by (2) the exchange ratio; and
    the exercise price per share of Dawson common stock subject to
    such converted stock option will be equal (1) to the
    exercise price per share of such TGC stock option divided by
    (2) the exchange ratio (with the exercise price per share,
    as so calculated, being rounded up to the nearest whole cent).  TGC
    Restricted Stock
   Payment
    of Merger Consideration  Exchange
    Fund
   98




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Exchange
    Procedures
          TGC stock certificates should not be returned with the
    enclosed proxy card(s). TGC stock certificates should be
    returned with a validly executed transmittal letter and
    accompanying instructions that will be provided to TGC
    shareholders following the effective time of the merger.
  Lost
    Stock Certificates
   99




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##### Table of Contents



Termination
    of Exchange Fund
    Withholding
    Taxes
   Representations
    and Warranties    
    due organization, good standing and the requisite corporate
    power and authority to own, operate and lease their respective
    properties and assets and to carry on their respective
    businesses;
    corporate power and authority to enter into the merger agreement
    and all other agreements and documents contemplated by the
    merger agreement, and due execution, delivery and enforceability
    of the merger agreement;
    board of directors approval and recommendation to their
    shareholders to approve the transactions contemplated by the
    merger agreement;
    receipt of a fairness opinion from their respective financial
    advisor to the effect that, subject to the assumptions,
    qualifications and limitations set forth in such opinion, as of
    the date of the merger agreement, the exchange ratio is fair,
    from a financial point of view, to Dawson, in the case of the
    opinion of Dawsons financial advisor, or TGC shareholders,
    in the case of the opinion of TGCs financial advisor;
    capital structure and outstanding equity securities;
    ownership of subsidiaries;
    absence of (1) conflicts with charter documents,
    (2) breaches of any provision of, or a termination or
    acceleration under, or the creation of a lien upon any of the
    properties or assets of Dawson or TGC or their respective
    subsidiaries, as the case may be, under, any of the provisions
    of any agreements, obligations, leases or contracts and
    (3) violations of applicable law, in each case, resulting
    from the execution and delivery of the merger agreement and
    consummation of the transactions contemplated by the merger
    agreement;
    absence of required governmental consents in connection with
    execution and delivery of the merger agreement and consummation
    of the transactions contemplated by the merger agreement other
    than governmental filings specified in the merger agreement;
    timely filing, since January 1, 2008, of required documents
    with the SEC, compliance with the requirements of the Securities
    Act, the Exchange Act, the Sarbanes-Oxley Act of 2002, the
    listing and corporate governance rules and regulations of
    NASDAQ, and the absence of untrue statements of material facts
    or omissions of material facts in those documents; 100




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
    compliance of financial statements as to form with applicable
    accounting requirements and SEC rules and regulations and
    preparation in accordance with GAAP;
    absence of any liabilities or obligations other than liabilities
    or obligations to the extent (1) reflected or reserved
    against the audited balance sheet as of September 30, 2010,
    in the case of Dawson, or the consolidated audited balance sheet
    as of December 31, 2010, in the case of TGC,
    (2) incurred in the ordinary course of business consistent
    with past practice since September 30, 2010, in the case of
    Dawson, or December 31, 2010, in the case of TGC, or
    (3) such liabilities or obligations have not had and would
    not reasonably be expected to have a material adverse effect on
    Dawson or TGC, as the case may be;
    implementation and maintenance of disclosure controls and
    internal accounting controls;
    compliance with applicable laws and holding of necessary permits;
    absence of proceedings before any governmental authority or
    subject to arbitration;
    absence of a material order, writ, fine, injunction, decree,
    judgment, award or determination of any governmental authority
    affecting the ownership or operation of any of their respective
    assets or of any criminal order, writ, fine, injunction, decree,
    judgment or determination of any court or governmental authority
    issued against Dawson or TGC, as the case may be, or any of
    their respective subsidiaries;
    absence, since September 30, 2010, in the case of Dawson,
    or December 31, 2010, in the case of TGC, of any event,
    change, occurrence, effect, or development of circumstances or
    facts that, individually or in the aggregate, would reasonably
    be expected to have a material adverse effect on Dawson or TGC,
    as the case may be;
    absence of specified changes or events and conduct of the
    business in the ordinary course since September 30, 2010,
    in the case of Dawson, or December 31, 2010, in the case of
    TGC;
    tax matters;
    employee benefits matters and ERISA compliance;
    labor matters and compliance with labor and employment law;
    environmental matters and compliance with environmental laws;
    real property and assets;
    intellectual property;
    insurance;
    certain material contracts;
    contracts with governmental authorities;
    no brokers or finders fees;
    absence of ownership of any shares of capital stock of the other
    party or any other securities convertible into or otherwise
    exercisable to acquire shares of capital stock of the other
    party;
    the affirmative vote required by shareholders of each party to
    approve the transactions contemplated by the merger agreement;
    absence of unlawful payments to foreign officials;
    with respect to TGC, the inapplicability of certain takeover
    laws or rights plans; and
    absence of transactions with affiliates. 101




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Definition
    of Material Adverse Effect      
    the business, properties, assets, liabilities (contingent or
    otherwise), condition (financial or otherwise), results of
    operations or prospects of Dawson or TGC, as the case may be, or
    any of their respective subsidiaries, taken as a whole, except
    for any such change, effect, event, occurrence, state of facts
    or development that arises or results from:  
    changes in general economic, capital market, regulatory or
    political conditions or changes in applicable law or the
    interpretation thereof that, in any case, do not
    disproportionately affect such party relative to other
    participants in the seismic industry;
    acts of war or terrorism that do not disproportionately affect
    such party in any material respect relative to other
    participants in the seismic industry; or
    the announcement or proposed consummation of the merger
    agreement and the transactions contemplated by the merger
    agreement; or  
    the ability of Dawson or TGC, as the case may be, to perform its
    obligations under the merger agreement and the transactions
    contemplated by the merger agreement. Covenants
    and Agreements  Operating
    Covenants
    
    amend its governing instruments;
    merge or consolidate with any person or acquire any person or
    assets, in any single transaction (or series of related
    transactions) in excess of $100,000;
    adjust, reclassify, split, combine, subdivide, authorize for
    issuance, issue or sell, pledge, dispose of or subject to any
    lien shares of capital stock or options, warrants, restricted
    stock, restricted stock units, convertible securities, stock
    appreciation rights, performance units, bonus stock,
    phantom stock rights, redemption rights, repurchase
    rights, agreements, arrangements, calls, commitments or other
    rights of any kind to acquire such shares, other than in
    connection with existing employee stock plans; 102




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
    except as required by existing employee benefit plans,
    (1) increase the compensation or benefits of any of its
    directors, executive officers or employees (except in the
    ordinary course of business consistent with past practice with
    respect to employees who are not executive officers or parties
    to an employment or change in control agreement), (2) grant
    severance or termination pay, other than nominal severance to
    terminated employees in the ordinary course of business
    consistent with past practice, (3) make any new equity
    awards to any director, officer, employee or contractor,
    (4) enter into or amend any employment, consulting, change
    in control or severance agreement or arrangement with present,
    former or future directors, officers, employees or contractors,
    (5) establish, adopt, enter into, freeze or amend in any
    material respect or terminate any employee benefit plan or take
    any action to accelerate entitlement to compensation or benefits
    under any employee benefit plan or otherwise for the benefit of
    any present, former or future director, officer, employee or
    contractor, except as otherwise permitted pursuant to items (1),
    (2) and (3) above, (6) pay, accrue or certify
    performance level achievements at levels in excess of actually
    achieved performance in respect of any component of an
    incentive-based award, or amend or waive any performance or
    vesting criteria or accelerate vesting, exercisability,
    distribution, settlement or funding under any employee benefit
    plan or otherwise for the benefit of any present, former or
    future director, officer, employee or contractor, (7) take
    any action that would result in the holder of an employment or
    change in control agreement having good reason
    (within the meaning of that agreement) to terminate employment
    and collect severance payments and benefits pursuant to that
    agreement, and (8) terminate the employment of any holder
    of an employment or change in control agreement other than for
    cause (within the meaning of that agreement);
    declare, set aside, make or pay any dividend or other
    distribution or payment with respect to any shares of any class
    of capital stock, other than dividends or distributions paid by
    a direct or indirect wholly owned subsidiary to its shareholders;
    except as required by existing employee benefit plans, redeem,
    purchase or otherwise acquire any of its or any of its
    subsidiaries capital stock, or make any commitment for any
    such action;
    sell, lease, license, subject to a lien, encumber or otherwise
    surrender, relinquish or dispose of any assets or properties
    except for (1) sales of surplus or obsolete equipment,
    (2) sales, leases, licenses or other transfers between
    Dawson or TGC, as the case may be, and their direct or indirect
    wholly owned subsidiaries or among such direct or indirect
    wholly owned subsidiaries or (3) sales, leases, licenses or
    other dispositions of assets or properties with a fair market
    value not in excess of $100,000;
    enter into any joint venture, partnership or other similar
    arrangement or make any loan, capital contribution or advance to
    or investment in any other person, other than any arrangement
    with or loan, capital contribution or advancement to a direct or
    indirect wholly owned subsidiary of Dawson or TGC, as the case
    may be;
    change any of the material accounting methods, policies,
    principles, procedures or practices except as may be required as
    a result of a change in GAAP;
    fail to maintain in full force without interruption its present
    insurance policies or comparable insurance coverage;
    (1) make or rescind any material election relating to
    taxes, (2) settle or compromise any material proceeding
    relating to taxes, except to the extent of any reserve reflected
    the last balance sheet filed with the SEC in Dawsons or
    TGCs, as the case may be, Annual Report on
    Form 10-K,
    (3) change in any material respect any of its methods of
    reporting any item for tax purposes, (4) amend any material
    tax return or file any material refund claim, (5) enter
    into a closing agreement with any taxing authorities, or
    (6) give or request any waiver of a statute of limitations
    with respect to any tax or tax return;
    settle or compromise any legal proceeding, other than in the
    ordinary course of business consistent with past practice, or
    enter into any consent, decree, injunction or other settlement
    of any material legal proceeding or waive, release or assign any
    rights or claims; 103




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
    (1) create, incur or assume any debt, issue or sell any
    debt securities or calls, options, warrants or other rights to
    acquire any debt securities, guarantee any debt or debt
    securities of another person, enter into any keep
    well or other contract to maintain any financial condition
    of another person or enter into any arrangement having the
    economic effect of any of the foregoing, except intercompany
    debt in the ordinary course of business consistent with past
    practice; (2) repurchase, repay, defease or pre-pay any
    debt, except (A) repayments in the ordinary course of
    business or (B) repayments of indebtedness by direct or
    indirect wholly owned subsidiary to its shareholders; or
    (3) except with respect any legal proceeding, pay,
    discharge or satisfy any material claims, liabilities or
    obligations other than in the ordinary course of business
    consistent with past practice;
    (1) mortgage, pledge, or suffer to exist any liens on, any
    asset or property, or (2) pledge or otherwise encumber any
    shares of capital stock;
    make, authorize or enter into commitments for capital
    expenditures in excess of $100,000 in the aggregate;
    other than in the ordinary course of business consistent with
    past practice, (1) modify, amend or terminate or waive any
    rights under any material contract, or (2) enter into any
    new agreement that would have been a material contract if it
    were entered into at or prior to the date of the merger
    agreement;
    enter into, renew, extend, amend, grant a waiver under or
    terminate any affiliated transaction or any transaction that
    would be an affiliated transaction if such transaction occurred
    prior to the date of the merger agreement;
    adopt or implement a plan of complete or partial liquidation,
    dissolution, restructuring, recapitalization or other
    reorganization;
    purchase or otherwise acquire, directly or indirectly, any of
    the capital stock of the other party or securities convertible
    or exchangeable into or exercisable for any shares of capital
    stock of the other party;
    take any action that would, or would reasonably be expected to,
    (1) result in any condition to the closing of the merger
    not being satisfied, (2) prevent, materially delay or
    materially impede the consummation of the merger or the other
    transactions contemplated by the merger agreement or
    (3) cause any representation in the merger agreement to be
    untrue as of the closing of the merger; or
    agree or commit to do any of the foregoing.  No
    Solicitation
  Non-Solicitation
    Agreement.
    
    solicit, initiate, approve, endorse, recommend or encourage, or
    take any other action designed to, or which would reasonably be
    expected to, facilitate any inquiry or the making or
    announcement of any proposal or offer that constitutes, or that
    would reasonably be expected to lead to, an acquisition proposal;
    engage, continue or otherwise participate in discussions or
    negotiations regarding, or furnish non-public information or
    provide access to properties, books or records to any person in
    connection with or in furtherance of any acquisition proposal;
    approve or recommend, or propose to approve or recommend, or
    consummate, execute or enter into any agreement constituting or
    related to, or that is intended to or would reasonably be
    expected to lead to an acquisition proposal; or
    propose publicly or agree to do any of the foregoing. 104




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
    direct or indirect acquisition or purchase of (1) assets or
    businesses that constitute 20% or more of the consolidated net
    revenues, net income or assets (based on either book or fair
    market value) of such party and its subsidiaries, or
    (2) 20% or more of any class of equity securities of such
    party;
    tender offer or exchange offer that if consummated would result
    in any person beneficially owning 20% or more of any class of
    equity securities of such party; or
    merger, consolidation, business combination, recapitalization,
    liquidation, dissolution, joint venture, share exchange or
    similar transaction involving such party.  Exceptions
    to Non-Solicitation.
    
    Dawson or TGC, as applicable, has not breached its
    non-solicitation covenant contained in the merger agreement in
    any material respect;
    the board of directors of Dawson or TGC, as applicable,
    determines in good faith, after receipt of advice from outside
    counsel and its financial advisor, that such acquisition
    proposal constitutes or is reasonably likely to lead to a
    superior proposal; and
    Dawson or TGC, as applicable, enters into a customary
    confidentiality agreement with the person making such
    acquisition proposal which is (1) no less favorable to
    Dawson or TGC, as applicable, and (2) no less restrictive
    of such person than the confidentiality agreement entered into
    between the Dawson and TGC and all such information provided to
    such person has previously been provided to or is provided to
    the other party concurrently with its provision to such person.    
    more favorable to such partys shareholders from a
    financial point of view than the merger, taking into account all
    the terms and conditions of such proposal, the person making
    such proposal and the merger agreement, including any
    break-up
    fees, expense reimbursement provisions, conditions to
    consummation, strategic considerations, legal and regulatory
    considerations, and any changes to the terms of the merger
    agreement proposed by the other party in response to such
    offer; and
    reasonably likely to be completed on the terms proposed, taking
    into account all financial, legal, regulatory and other aspects
    of such proposal.  Agreement
    Not to Change Recommendation.
    
    fail to make, withdraw, modify or qualify, or propose publicly
    to withhold, withdraw, modify or qualify, in any manner adverse
    to the other party, its recommendation to shareholders that they
    approve the transactions contemplated by the merger agreement; 105




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
    make any other public statement that is inconsistent with such
    recommendation;
    recommend, endorse, adopt or approve, or propose publicly to
    recommend, endorse, adopt or approve, any acquisition
    proposal; or
    fail to reaffirm or re-publish within five business days upon
    request by the other party (publicly if so requested) its
    recommendation.  Exceptions
    to Restriction on Changing Recommendation.
    
    an acquisition proposal has been made and not withdrawn;
    Dawsons or TGCs board of directors, as the case may
    be, determines in good faith, after receipt of advice from
    outside counsel and a financial advisor of nationally recognized
    reputation, that such acquisition proposal constitutes a
    superior proposal;
    Dawsons or TGCs board of directors, as the case may
    be, determines in good faith, after receipt of advice from
    outside counsel, that the failure to take such action would be
    reasonably likely to result in a breach of fiduciary duties to
    the shareholders of Dawson or TGC, as applicable;
    in the case of terminating the merger agreement to enter into an
    acquisition proposal, Dawson or TGC, as applicable, has paid the
    other party a termination fee equal to $2.35 million.    
    until after the third business day following the delivery of
    notice of intent to change its recommendation or terminate the
    merger agreement and enter into an agreement providing for a
    superior proposal by the party taking such action, which we
    refer to as the no-shop party;
    unless during such three business day period, the no-shop party
    shall, and shall cause its financial and legal advisors to, upon
    the other partys request, discuss with the other party in
    good faith any adjustments to the terms and conditions of the
    merger agreement that the other party may propose in response to
    the superior proposal; and
    if, prior to the expiration of such three business day period,
    the other party makes a proposal to adjust the terms and
    conditions of merger agreement that the no-shop partys
    board of directors determines in good faith, after receipt of
    advice from outside legal counsel and a financial advisor of
    nationally recognized reputation, to be at least as favorable as
    the superior proposal.     106




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Other
    Matters.
        Meeting
    of Shareholders
      Filings;
    Reasonable Best Efforts
    
    the taking of all acts necessary, proper or advisable to cause
    the conditions to the merger to be satisfied;
    preparing and filing as promptly as practicable with any
    governmental authority or other third party documentation to
    effect all necessary filings, notices, petitions, statements,
    registrations, submissions of information, applications or other
    documents; and
    obtaining and maintaining all approvals, consents,
    registrations, permits, authorizations and other confirmations
    required to be obtained from any governmental authority or other
    third party that are 107




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necessary, proper or advisable to consummate the merger and the
    other transactions contemplated by the merger agreement.          Inspection
      Listing
    Application
    Indemnification
    and Insurance
   108




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Employee
    Benefits Matters
        Employment
    Agreements
 
   
 109




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Certain
    Additional Agreements
    
    preparation of this joint proxy statement/prospectus and of the
    registration statement on
    Form S-4,
    of which this joint proxy statement/prospectus forms a part;
    requiring consultation with the other party regarding public
    announcements;
    ensuring exemption of certain transactions in connection with
    the proposed merger under
    Rule 16b-3
    of the Exchange Act;
    whether or not the merger is consummated, sharing equally
    (1) the fees incident to the filings required under the HSR
    Act and other antitrust laws, (2) SEC and other filing fees
    incident to this joint proxy statement/prospectus, including the
    costs and expenses associated with printing the joint proxy
    statement/prospectus and (3) the fees associated with
    causing the shares of Dawson common stock to be issued pursuant
    to the merger agreement to be listed on NASDAQ;
    in the event any takeover statutes are or become applicable to
    the merger and the other transactions contemplated by the merger
    agreement, granting such approvals and taking such actions as
    may be necessary so that the transactions may be consummated as
    promptly as practicable;
    providing the other party with prompt notice of (1) any
    representation or warranty made by it or contained in the merger
    agreement becoming untrue or inaccurate in any material respect
    and (2) the failure by it to comply with or satisfy in any
    material respect any covenant, condition or agreement to be
    complied with or satisfied by it under the merger agreement;
    providing the other party with the opportunity to reasonably
    participate in the defense of any shareholder litigation against
    either company or any of its directors relating to the merger or
    any other transactions contemplated by the merger
    agreement; and
    using reasonable best efforts to cause the merger to qualify as
    a reorganization within the meaning of Section 368(a) of
    the Code.   Conditions
    to Completion of the Merger    
    the approval of the merger agreement by TGC shareholders at the
    TGC special meeting;
    the approval by Dawson shareholders of the issuance of shares of
    Dawson common stock pursuant to the merger agreement;
    the absence of any (1) judgment, injunction, order or
    decree of any governmental authority of competent jurisdiction
    in the United States that would prohibit or enjoin the
    consummation of the merger shall be in effect and (2) law,
    statute, rule or regulation enacted by any governmental
    authority of competent jurisdiction in the United States which
    prohibits or makes unlawful the consummation of the merger;
    the effectiveness of the registration statement on
    Form S-4
    of which this joint proxy statement/prospectus forms a part and
    absence of any stop order by the SEC or proceedings of the SEC
    seeking a stop order;
    the approval for listing on NASDAQ, subject to official notice
    of issuance, of the shares of Dawson common stock to be issued
    in the merger; 110




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
    the receipt by TGC from Haynes and Boone, LLP, its counsel, of
    an opinion, in a form and substance reasonably satisfactory to
    TGC and dated as of the closing date of the merger, to the
    effect that (1) the merger will be treated as a
    reorganization within the meaning of Section 368(a) of the
    Code and (2) no gain or loss will be recognized for United
    States federal income tax purposes by TGC shareholders who
    exchange TGC common stock for Dawson common stock pursuant to
    the merger (except with respect to cash received in lieu of
    fractional shares); and
    the receipt by Dawson from Baker Botts, L.L.P., its counsel, of
    an opinion, in a form and substance reasonably satisfactory to
    Dawson and dated as of the closing date of the merger, to the
    effect that (1) the merger will be treated as a
    reorganization within the meaning of Section 368(a) of the
    Code and (2) no gain or loss will be recognized for United
    States federal income tax purposes by TGC shareholders who
    exchange TGC common stock for Dawson common stock pursuant to
    the merger (except with respect to cash received in lieu of
    fractional shares).    
    the representations and warranties of Dawson and Merger Sub set
    forth in the merger agreement (1) that are qualified as to
    materiality or material adverse effect are true and correct as
    so qualified, and (2) that are not so qualified are true
    and correct in all material respects, in each case as of the
    date of the merger agreement and as of the closing date of the
    merger, except to the extent such representations and warranties
    expressly relate to an earlier date (in which case as of such
    earlier date);
    Dawson and Merger Sub shall have performed, in all material
    respects, the covenants and agreements contained in the merger
    agreement and required to be performed by them on or prior to
    the closing date of the merger;
    the absence of any change, event, occurrence, state of facts or
    development occurring from the date of the merger agreement and
    that is continuing as of the closing date that, individually or
    in the aggregate, has had or would reasonably be likely to have
    a material adverse effect on Dawson;
    the receipt by TGC of a certificate of Dawson and Merger Sub,
    executed on behalf of each of them by their Chief Executive
    Officer or Chief Financial Officer, dated as of the closing date
    of the merger, certifying as to truth and correctness, with the
    applicable qualifications, if any, of the representations and
    warranties of Dawson and Merger Sub, the performance by Dawson
    and Merger Sub in all material respects of the covenants and
    agreements required to be performed by them under the merger
    agreement at or prior to the closing and the absence of a
    material adverse effect on Dawson since the date of the merger
    agreement; and 
  
    receipt by TGC of the reconfirmation opinion, which is a
    reconfirmation from TGCs financial advisor, as of the
    closing date, that the exchange ratio is fair, from a financial
    point of view, to TGC shareholders which will involve an updated
    review and analysis of the item set forth in the bullet points
    listed on pages 78-79 under THE MERGER 
    Opinion of TGCs Financial Advisor as and to the
    extent TGCs financial advisor deems appropriate. 
    
    the representations and warranties of TGC set forth in the
    merger agreement (1) that are qualified as to materiality
    or material adverse effect are true and correct as so qualified,
    and (2) that are not so qualified are true and correct in
    all material respects, in each case as of the date of the merger
    agreement and as of the closing date of the merger, except to
    the extent such representations and warranties expressly relate
    to an earlier date (in which case as of such earlier date);
    TGC shall have performed, in all material respects, the
    covenants and agreements contained in the merger agreement and
    required to be performed by it on or prior to the closing date
    of the merger; 111




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
    the absence of any change, event, occurrence, state of facts or
    development occurring from the date of the merger agreement and
    that is continuing as of the closing date that, individually or
    in the aggregate, has had or would reasonably be likely to have
    a material adverse effect on TGC;
    the receipt by Dawson of a certificate of TGC, executed on its
    behalf by its Chief Executive Officer or Chief Financial
    Officer, dated as of the closing date of the merger, certifying
    as to truth and correctness, with the applicable qualifications,
    if any, of the representations and warranties of TGC, the
    performance by TGC in all material respects of the covenants and
    agreements required to be performed by it under the merger
    agreement at or prior to the closing and the absence of a
    material adverse effect on TGC since the date of the merger
    agreement;
    TGC shall have obtained certain authorizations, consents or
    approvals to the merger and the other transactions contemplated
    by the merger agreement from certain third parties; and
    certain key employees of TGC shall have entered into employment
    agreements with TGC, as the surviving entity of the merger, as
    of the effective time of the merger. Termination
    of the Merger Agreement      
    the merger has not occurred on or before August 31, 2011
    (October 31, 2011 if all conditions, other than
    (1) the termination or expiration of the waiting period
    under the HSR Act or (2) the absence of any judgment,
    injunction, order or decree in effect, or any law, statute, rule
    or regulation enacted, that prohibits the consummation of the
    merger, have been or are capable of being fulfilled), or the
    termination date, but neither party may terminate the merger
    agreement if that partys failure to perform or observe in
    any material respect any of its obligations under the merger
    agreement in any manner has caused or resulted in the failure of
    the merger to occur on or before the termination date;
    TGC shareholders fail to approve the merger agreement at the TGC
    special meeting;
    Dawson shareholders fail to approve the issuance of Dawson
    common stock pursuant to the merger agreement at the Dawson
    special meeting;
    a governmental authority shall have issued an order, decree or
    ruling or taken any other action permanently restraining,
    enjoining or otherwise prohibiting the merger and that order,
    decree, ruling or other action shall have become final and
    nonappealable, as long as the party seeking to terminate the
    merger agreement has complied with its obligations pursuant
    under the merger agreement with respect to the order, decree,
    ruling or other action; and
    the 10-day
    average VWAP of Dawson common stock as of [  ],
    2011 is less than $32.54 or greater than $52.54 and the parties
    have failed, after two business days of good faith negotiation,
    to have agreed to a new exchange ratio, provided the party
    seeking termination shall have provided the other parties with
    notice of intent to terminate not less than two business days
    prior to such termination.    
    Dawson or Merger Sub has breached or failed to perform any of
    its representations and warranties, covenants or agreements in
    the merger agreement such that the conditions to the closing of
    the merger agreement related to the accuracy of the
    representations and warranties or the performance of the
    covenants of Dawson and Merger Sub would fail and that breach or
    failure is incapable of being cured prior to the termination
    date or is not cured within 30 days after notice of the
    breach or failure to 112




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perform, as long as TGC is not in breach of any representation,
    warranty, covenant or agreement in the merger agreement such
    that the conditions to the closing of the merger agreement
    related to the accuracy of the representations and warranties or
    the performance of the covenants of TGC would fail;  
    Dawsons board of directors changes its recommendation;
    prior to obtaining the required approval of its shareholders,
    TGC enters into a binding definitive agreement providing for a
    superior proposal, as long as TGC has complied in all respects
    with the non-solicitation provisions of the merger agreement and
    TGC pays Dawson a termination fee of $2.35 million; or
    TGC shall have not received the reconfirmation opinion and all
    other mutual conditions to the closing of the merger have been
    satisfied, as long as TGC is not in breach of any
    representation, warranty, covenant or agreement in the merger
    agreement such that the conditions to the closing of the merger
    agreement related to the accuracy of the representations and
    warranties or the performance of the covenants of TGC would fail.    
    TGC has breached or failed to perform any of its representations
    and warranties, covenants or agreements in the merger agreement
    such that the conditions to the closing of the merger agreement
    related to the accuracy of the representations and warranties or
    the performance of the covenants of TGC would fail and that
    breach or failure is incapable of being cured prior to the
    termination date or is not cured within 30 days after
    notice of the breach or failure to perform, as long as Dawson is
    not in breach of any representation, warranty, covenant or
    agreement in the merger agreement such that the conditions to
    the closing of the merger agreement related to the accuracy of
    the representations and warranties or the performance of the
    covenants of Dawson would fail;
    TGCs board of directors changes its recommendation;
    prior to obtaining the required approval of its shareholders,
    Dawson enters into a binding definitive agreement providing for
    a superior proposal, as long as Dawson has complied in all
    respects with the non-solicitation provisions of the merger
    agreement and Dawson pays TGC a termination fee of
    $2.35 million; or
    TGC shall have not received the reconfirmation opinion and all
    other mutual conditions to the closing of the merger have been
    satisfied, as long as TGC is not in breach of any
    representation, warranty, covenant or agreement in the merger
    agreement such that the conditions to the closing of the merger
    agreement related to the accuracy of the representations and
    warranties or the performance of the covenants of TGC would fail. Termination
    Fee and Expense Reimbursement  Termination
    Fee
    
    an acquisition proposal relating to at least 50% of TGCs
    common stock or assets is made public and subsequent to such
    public announcement,  
    the merger agreement is terminated due to (1) the merger
    not closing on or before August 31, 2011 (or, in certain
    circumstances, October 31, 2011), (2) TGC shareholders
    not approving the merger agreement or (3) TGC breaching or
    failing to perform any of its representations and warranties,
    covenants or agreements in the merger agreement, and
    TGC enters into a definitive agreement relating to an
    acquisition proposal within one year after termination of the
    merger agreement; 113




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
    TGCs board of directors changes, or fails to reaffirm when
    requested by Dawson, its recommendation that TGC shareholders
    approve the merger agreement; or
    TGC entering into a binding definitive agreement providing for a
    superior proposal.        
    an acquisition proposal relating to at least 50% of
    Dawsons common stock or assets is made public and
    subsequent to such public announcement,  
    the merger agreement is terminated due to (1) the merger
    not closing on or before August 31, 2011 (or, in certain
    circumstances, October 31, 2011), (2) Dawson
    shareholders not approving the issuance of shares of Dawson
    common stock pursuant to the merger agreement or (3) Dawson
    breaching or failing to perform any of its representations and
    warranties, covenants or agreements in the merger
    agreement, and
    Dawson enters into a definitive agreement relating to an
    acquisition proposal within one year after termination of the
    merger agreement;  
    Dawsons board of directors changes, or fails to reaffirm
    when requested by TGC, its recommendation that Dawson
    shareholders approve the issuance of shares of Dawson common
    stock in connection with the proposed merger; or
    Dawson entering into a binding definitive agreement providing
    for a superior proposal.    Expense
    Reimbursement
    
    TGC or Dawson due to TGC shareholders failing to approve the
    merger agreement, as long as an acquisition proposal relating to
    at least 50% of TGCs common stock or assets is made public
    prior to the TGC special meeting and within 12 months after
    termination of the merger agreement, TGC or its subsidiaries
    enter into a definitive agreement in respect of any acquisition
    proposal or an acquisition proposal is consummated by TGC;
    TGC due to TGC entering into a binding definitive agreement
    providing for a superior proposal;
    TGC or Dawson due to TGC not receiving the reconfirmation
    opinion;
    Dawson due to a TGC breach or failure to perform any of its
    representations and warranties, covenants or agreements in the
    merger agreement; or
    Dawson due to TGCs board of directors changing or failing
    to reaffirm its recommendation to its shareholders.   114




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
    TGC or Dawson due to Dawson shareholders failing to approve the
    issuance of shares of Dawson common stock pursuant to the merger
    agreement, as long as an acquisition proposal relating to at
    least 50% of Dawsons common stock or assets is made public
    prior to the Dawson special meeting and within 12 months
    after termination of the merger agreement, Dawson or its
    subsidiaries enter into a definitive agreement in respect of any
    acquisition proposal or an acquisition proposal is consummated
    by Dawson;
    Dawson due to Dawson entering into a binding definitive
    agreement providing for a superior proposal;
    TGC due to a Dawson breach or failure to perform any of its
    representations and warranties, covenants or agreements in the
    merger agreement; or
    TGC due to Dawsons board of directors changing or failing
    to reaffirm its recommendation to its shareholders.       Amendments,
    Extensions and Waivers  Amendments
    Extensions
    and Waivers
    
    extend the time for the performance of any of the obligations or
    other acts of the other parties;
    waive any inaccuracies in the representations and warranties of
    the other party contained in the merger agreement or in any
    document delivered pursuant to the merger agreement; or
    waive compliance by the other party with any of the agreements
    or conditions contained in the merger agreement. 115




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Specific
    Performance   
 Governing
    Law   116




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THE TGC
    SHAREHOLDER VOTING AGREEMENTS  The following summary describes the material provisions of
    the TGC shareholder voting agreements. The provisions of the TGC
    shareholder voting agreements are complicated and not easily
    summarized. This summary may not contain all of the information
    about the TGC shareholder voting agreements that is important to
    you. This summary is qualified in its entirety by reference to
    the form of TGC shareholder voting agreement attached as
    Annex D to, and incorporated by reference into, this joint
    proxy statement/prospectus. We encourage you to read it
    carefully in its entirety for a more complete understanding of
    the TGC shareholder voting agreements.
 No
    Disposition  power-of-attorney
   Voting of
    Shares of TGC Common Stock    
    approval of the merger agreement at the TGC special meeting;
    any proposal to adjourn the TGC special meeting to a later date
    if there are not sufficient votes for the approval of the merger
    agreement; and
    any matter necessary for the consummation of the transactions
    contemplated by the merger agreement.    
    any agreement or arrangement related to or in furtherance of any
    acquisition proposal;
    any liquidation of TGC or its subsidiaries;
    any action, proposal, transaction or agreement that would delay,
    prevent, frustrate, impede or interfere with the merger or the
    other transaction contemplated by the merger agreement or result
    in the failure of any condition of the merger to be
    satisfied; and
    any action, proposal, transaction or agreement that would result
    in a breach of any covenant, representation or warranty or other
    obligation or agreement of TGC under the merger agreement or the
    TGC shareholder voting agreement. Irrevocable
    Proxy   117




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
    vote all shares of TGC common stock beneficially owned by such
    officer or director;
    grant or withhold a consent or approval in respect of such
    shares of TGC common stock beneficially owned by such officer or
    director; and
    execute and deliver a proxy to vote such shares of TGC common
    stock beneficially owned by such officer or director. Termination
    of the TGC Shareholder Voting Agreements   Shareholder
    Capacity   Specific
    Performance   Governing
    Law   118




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THE
    DAWSON SHAREHOLDER VOTING AGREEMENT  The following summary describes the material provisions of
    the Dawson shareholder voting agreement. The provisions of the
    Dawson shareholder voting agreement are complicated and not
    easily summarized. This summary may not contain all of the
    information about the Dawson shareholder voting agreement that
    is important to you. This summary is qualified in its entirety
    by reference to the form of Dawson shareholder voting agreement
    attached as Annex E to, and incorporated by reference into,
    this joint proxy statement/prospectus. We encourage you to read
    it carefully in its entirety for a more complete understanding
    of the Dawson shareholder voting agreement.
 No
    Disposition  power-of-attorney
   Voting of
    Shares of Dawson Common Stock    
    approval of the issuance of shares of Dawson common stock
    pursuant to the merger agreement at the Dawson special meeting;
    any proposal to adjourn the Dawson special meeting to a later
    date if there are not sufficient votes for the approval of the
    share issuance; and
    any matter necessary for the consummation of the transactions
    contemplated by the merger agreement.    
    any agreement or arrangement related to or in furtherance of any
    acquisition proposal;
    any liquidation of Dawson or its subsidiaries;
    any action, proposal, transaction or agreement that would delay,
    prevent, frustrate, impede or interfere with the merger or the
    other transaction contemplated by the merger agreement or result
    in the failure of any condition of the merger to be
    satisfied; and
    any action, proposal, transaction or agreement that would result
    in a breach of any covenant, representation or warranty or other
    obligation or agreement of Dawson under the merger agreement or
    the Dawson shareholder voting agreement. Irrevocable
    Proxy   119




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
    vote all shares of Dawson common stock beneficially owned by
    such officer or director;
    grant or withhold a consent or approval in respect of such
    shares of Dawson common stock beneficially owned by such officer
    or director; and
    execute and deliver a proxy to vote such shares of Dawson common
    stock beneficially owned by such officer or director. Termination
    of the Dawson Shareholder Voting Agreement   Shareholder
    Capacity   Specific
    Performance   Governing
    Law   120




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THE
    EMPLOYMENT AGREEMENTS  It is a condition to the Merger Agreement that:
    (1) Dawson enter into an employment agreement with
    Mr. Jumper and (2) TGC, as the surviving entity of the
    merger, as of the effective time of the merger, enter into
    employment agreements with each of Messrs. Whitener, Brata,
    Winn and Wood, in each case, substantially in the form of the
    employment agreement attached as Annex F to, and
    incorporated by reference into, this joint proxy
    statement/prospectus.  Mr. Wood has indicated that he will
    continue his employment with Eagle Canada, Inc. pursuant to his
    current employment agreement which is in effect until
    October 31, 2012.
  The following summary describes the material provisions of
    the employment agreements. The provisions of the employment
    agreements are complicated and not easily summarized. This
    summary may not contain all of the information about the
    employment agreements that is important to you. This summary is
    qualified in its entirety by reference to the form of employment
    agreement. We encourage you to read it carefully in its entirety
    for a more complete understanding of the employment
    agreements.
 Term   Duties
    and Compensation             Termination
    of the Employment Agreements      
    upon the death of the executive; 121




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
    by the employing company:  
    immediately for cause;
    upon 30 days prior notice other than for cause or for no
    reason; or
    upon 30 days prior notice upon the executives
    disability;  
    by the executive:  
    upon 30 days prior notice for any reason; or
    for good reason within 30 days after the employing company
    has already had 30 days in which to cure the reasons
    provided by the executive for terminating the employment
    agreement and has not cured the good reason cause of the
    executives termination.    
    fraud, embezzlement, misappropriation of funds, willful or
    intentional misconduct or gross negligence in connection with
    the business of the employing company or its affiliates;
    commission or conviction of any felony or of any misdemeanor
    involving theft or moral turpitude, or entry of a plea of guilty
    or nolo contendere to any felony or any misdemeanor involving
    theft or moral turpitude;
    acts of dishonesty or disloyalty that adversely affect or could
    reasonably be expected to adversely affect the employing company
    or its affiliates in any material respect;
    engagement in any activity that the executive knows or should
    know could materially harm the business or reputation of the
    employing company or its affiliates, including alcohol or
    substance abuse that has impaired or could reasonably be
    expected to impair the ability of the executive to perform his
    or her duties;
    a material failure to adhere to requirements applicable to the
    employing companys operations, published corporate codes,
    policies or procedures of the employing company;
    the executives failure to meet applicable performance
    standards as determined by the board of directors from time to
    time;
    the executives excess absenteeism, willful or persistent
    neglect of, or abandonment of his or her duties (other than due
    to illness or any other physical condition that could reasonably
    be expected to result in disability); or
    a material breach of any contract entered into between the
    executive and the employing company or an affiliate of the
    employing company including the employment agreement.    
    the assignment to the executive of any duties inconsistent in
    any respect with the executives position (including
    status, offices, titles and reporting requirements), authority,
    duties, or responsibilities, or any other action by the
    employing company which results in a diminution in such
    position, authority, duties, or responsibilities, excluding for
    this purpose an isolated, insubstantial, and inadvertent action
    not taken in bad faith and which is remedied by the employing
    company within 20 days after notice;
    any material reduction in the amount or type of compensation and
    benefits paid to the executive;
    the employing company requiring the executive to be based at any
    office or location other than facilities within 50 miles of
    the executives base of operations;
    the employing company materially interfering with the
    executives ability to fulfill his or her duties;
    any material breach of any material contract entered into
    between the executive and the employing company or an affiliate
    of the employing company, including the employment agreement; 122




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
    a direction or order from the Executives manager or the
    employing companys board of directors that the Executive
    takes actions that are illegal or unethical; or
    any purported termination by the employing company of the
    executives employment otherwise than as expressly
    permitted by the employment agreement. Payment
    upon Termination     Restrictive
    Covenants    
    acting alone or in conjunction with others, or as an employee,
    consultant or independent contractor, or as partner, officer,
    director, shareholder, manager, member or owner of any interest
    in or security of, any entity engage or participate, for
    compensation or without compensation, in any business which is
    in competition with the employing company or its affiliates as
    conducted at the time of termination of the executives
    employment by the employing company in the geographic locations
    where the employing company or its affiliates does business;
    solicit any client of the employing company or its affiliates
    with whom the executive conducted business during the term of
    the employment agreement either to purchase products or services
    that are competitive to the products and services then sold by
    the employing company or to reduce or cease business with the
    employing company or its affiliates; or
    hire or induce or solicit any current employee of the employing
    company or any affiliate or any person who was an employee of
    the employing company or any affiliate during the final
    12 months of the executives employment to terminate
    the employees employment with the employing company or to
    work for the executive or the executives employer.   123




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
    a period of one year after termination of the executives
    employment, in the case of a termination by the employing
    company for cause or disability, or by the executive without
    good reason;
    for the longer of (1) one year or (2) the remainder of
    the term of the employment agreement, in the case of termination
    by the employing company without cause or by the executive with
    good reason; or
    in the case of expiration of the employment agreement,
    (1) if the employing company elects not to renew the
    employment agreement, a period of six months after termination
    with respect to the executives covenant not to solicit
    employees, but the executive need not abide by the obligation
    not to compete or not to solicit clients or (2) if the
    executive elects not to renew, a period of six months after
    termination, provided that, during the six-month term, the
    employing company continues to pay the executive his or her
    then-current base salary. Governing
    Law   Description
    of Specific Employment Agreements    Annual

Perquisites/Executive

Employing Company

Title

Base Salary

Benefits(1)Stephen C. Jumper

Dawson

President and Chief Executive Officer


$385,000


$
9,900Wayne A. Whitener

TGC

President


300,000



9,900Daniel G. Winn

TGC

Vice President


193,000



9,300James K. Brata

TGC

Vice President


180,000



8,700     (1)
    
    Based on the estimated annual cost of providing a vehicle, fuel,
    insurance, maintenance, repair and other reasonable costs. 124




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MATERIAL
    U.S. FEDERAL INCOME TAX CONSEQUENCES OF THE MERGER General   
  
    financial institutions;
    mutual funds;
    tax-exempt organizations;
    insurance companies;
    S corporations, partnerships or other pass through entities
    for U.S. federal income tax purposes;
    dealers in securities, commodities or foreign currencies;
    traders in securities who elect to apply a
    mark-to-market
    method of accounting;
    holders who are not U.S. holders, as defined below;
    persons subject to U.S. alternative minimum tax;
    persons who hold shares of TGC common stock as part of a hedge,
    straddle, constructive sale, conversion or other integrated
    transaction; or
    holders who acquired their shares of TGC common stock upon the
    exercise of options or similar derivative securities or
    otherwise as compensation.  TGC shareholders
    are urged to consult their tax advisors as to the specific tax
    consequences of the merger to them, including the applicability
    and effect of U.S. federal, state, local and foreign income
    and other tax laws in their particular circumstances.
    
    an individual who is a citizen or resident of the United States;
    a corporation (or other entity taxable as a corporation for
    U.S. federal income tax purposes) created or organized in
    or under the laws of the United States, any state thereof or any
    political subdivision thereof, or the District of Columbia;
    an estate the income of which is includible in gross income for
    U.S. federal income tax purposes regardless of its
    source; or
    a trust if (1) a court within the United States is able to
    exercise primary supervision over the administration of the
    trust and one or more U.S. persons have the authority to
    control all substantial 125




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decisions of the trust or (2) the trust has a valid
    election in effect under applicable Treasury regulations to be
    treated as a U.S. person.   Qualification
    of the Merger as a Reorganization and Tax Opinions   
 
  statement/prospectus statement/prospectus statement/prospectus
 
   Material
    U.S. Federal Income Tax Consequences if the Merger Qualifies as
    a Tax-Free Reorganization    
    a U.S. holder whose TGC common stock is exchanged in the
    merger for Dawson common stock will not recognize gain or loss
    in the merger, except with respect to cash, if any, received in
    lieu of a fractional share of Dawson common stock;
    a U.S. holders aggregate tax basis in the Dawson
    common stock received in the merger, including any fractional
    share deemed received and redeemed as described below, will
    equal the aggregate tax basis of the TGC common stock
    surrendered by such U.S. holder in the merger;
    a U.S. holders holding period for the Dawson common
    stock received in the merger will include the
    U.S. holders holding period for the TGC common stock
    surrendered in the merger; and 126




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
    a U.S. holder who receives cash in lieu of a fractional
    share of Dawson common stock in the merger will be treated as
    having received the fractional share in the merger and then as
    having received the cash in redemption of such fractional share.
    As a result, such a U.S. holder should generally recognize
    capital gain or loss equal to the difference between the amount
    of the cash received in lieu of the fractional share and the
    U.S. holders tax basis allocable to such fractional
    share. The capital gain or loss will be long-term capital gain
    or loss if the holding period for the TGC stock exchanged for
    cash in lieu of the fractional Dawson common share is more than
    one year as of the effective date of the merger. The
    deductibility of capital losses is subject to limitations. Material
    U.S. Federal Income Tax Consequences if the Merger Fails to
    Qualify as a Tax-Free Reorganization  e.g.
 Backup
    Withholding and Information Reporting  e.g., Form W-9 Form W-9
 Reporting
    Requirements    The foregoing discussion is not intended to be legal or tax
    advice to any particular TGC shareholder. Tax matters regarding
    the merger are very complicated and the tax consequences of the
    merger to any particular TGC shareholder will depend on that
    shareholders particular situation. TGC shareholders are
    urged to consult their own tax advisors regarding the specific
    tax consequences of the merger, including tax return reporting
    requirements, the applicability of federal, state, local and
    foreign tax laws and the effect of any proposed change in the
    tax laws to them.
 127




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COMPARISON
    OF SHAREHOLDER RIGHTS     
   
  
 Dawson

TGCCapital StockDawson is authorized to issue:

TGC is authorized to issue:   50,000,000 shares of common stock, par value
    $0.331/3
    per share, of which 7,910,885 were issued and outstanding as of
    July 8, 2011; and

   25,000,000 shares of common stock, par value
    $0.01 per share, of which 19,277,770 were issued and outstanding
    as of July 8, 2011; and   5,000,000 shares of preferred stock, of which
    500,000 have been designated Series A Junior Participating
    Preferred Stock, par value $1.00 per share, or Dawson
    Series A preferred stock, and reserved for issuance upon
    exercise of the rights described under  Rights
    Plan below.

   4,000,000 shares of preferred stock, of which
    none are issued and outstanding.Rights PlansPursuant to a rights agreement, effective as of July 23,
    2009, between Dawson and Mellon Investors Services LLC, as
    rights agent, Dawson shareholders may purchase one one-hundredth
    of a share of Dawson Series A preferred stock at a purchase
    price of $130.00 per such fractional share, subject to
    adjustment, for each share of Dawson common stock they own.

TGC is not a party to any rights agreement or a similar plan.These rights are exercisable only upon a distribution
    date and, unless earlier redeemed or exchanged, expire at
    the close of business on July 23, 2019. A distribution date
    will occur, with certain exceptions, upon the earlier of
    (1) 10 days after public announcement that a person or
    group has acquired, or obtained the right to acquire, beneficial
    ownership of 15% or more of the outstanding shares of Dawson
    common stock or (2) 10 business days following commencement
    of a tender or exchange offer that would result in a person
    acquiring beneficial ownership of 15% or more of the outstanding
    shares of Dawson common stock. 128




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Dawson

TGCThese rights will not be exercisable in connection with the
    merger or any of the other transactions contemplated by the
    merger agreement.Anti-Takeover ProvisionsSee  Rights Plan above.

The affirmative vote of the holders of 80% or more of the issued
    and outstanding shares of TGC common stock at a duly called
    meeting is required to approve or authorize (1) any merger or
    consolidation of TGC with or into another company, or (2) any
    sale of all or substantially all of TGCs assets to another
    company.As discussed throughout this joint proxy statement/prospectus,
    the merger cannot be consummated unless holders of 80% or more
    of the issued and outstanding shares of TGC common stock approve
    the merger agreement at the TGC special meeting.Number of DirectorsThe Dawson board of directors must consist of not less than five
    nor more than fifteen directors, with the exact number fixed
    from time to time by (1) resolution of the Dawson board of
    directors or (2) Dawson shareholders at an annual meeting
    of shareholders.

The TGC board of directors must consist of not less than one nor
    more than nine directors, with the exact number fixed from time
    to time by resolution of the TGC board of directors
    Currently, there are six directors on the TGC board of
    directors.Currently, there are eight directors on the Dawson board of
    directors. At the effective time of the merger, we expect the
    Dawson board of directors to be increased to 10 directors.Classification of Board of DirectorsDawson has one class of directors and Dawsons second
    restated articles of incorporation does not provide for a
    classified board of directors. Dawsons directors are
    generally elected to hold office until the next annual meeting
    of shareholders.

TGCs amended and restated bylaws provide that if
    TGCs board of directors consists of 9 directors, upon
    resolution of the TGC board of directors, the directors may be
    divided into three equal classes, with each class having a
    staggered three-year term.  
    Currently TGC has one class of directors and directors are
    generally elected to serve until the annual meeting of
    shareholders for the year in which their term expires.Removal of DirectorsA Dawson director or the entire board of directors may be
    removed, with or without cause, at a meeting called for that
    purpose, by the affirmative vote of the holders of a majority of
    the issued and outstanding shares of Dawson common stock.

A TGC director may be removed prior to the end of his or her
    term only for cause at a special or annual meeting of
    shareholders by the affirmative vote of the holders of 80% or
    more of the issued and outstanding shares of TGC common stock if
    notice of intention to act upon such matter has been given in
    the notice calling such meeting.Special Meeting of ShareholdersSpecial meetings of Dawson shareholders (1) may be called
    by the board of directors, the chairman of the board, the Chief
    Executive Officer or the President or (2) shall be called
    by the President or the Secretary

Special meetings of TGC shareholders may be called (1) by the
    President or the board of directors acting pursuant to a
    resolution adopted by a majority of the entire board or (2) by
    the holders of at least 10% of 129




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Dawson

TGCon the written request of the holders of not less than the
    minimum percentage of shares of Dawson entitled to vote at the
    proposed special meeting that is

all the shares entitled to vote at the proposed special
    meeting.specified by Dawsons second restated articles of
    incorporation as necessary to call a special meeting of
    shareholders (or in the absence of such specification, the
    minimum percentage necessary to call a special meeting specified
    by Texas law).Shareholder NominationsAny shareholder entitled to vote in the election of directors
    may nominate a person for election to the Dawson board of
    directors. We refer to such nominating shareholder as the
    nominator. Any such nomination must be in writing and timely. To be
    timely in connection with an annual meeting of shareholders,
    such notice, setting forth the name and address of the person to
    be nominated, must be delivered to or mailed and received at
    Dawsons principal executive offices not less than
    90 days nor more than 120 days prior to the first
    anniversary of the date on which the immediately preceding
    years annual meeting of shareholders was held; provided,
    however, that if the date of the annual meeting is advanced more
    than 30 days prior to or delayed by more than 60 days
    after the first anniversary of the preceding years annual
    meeting, notice by the nominator to be timely must be so
    delivered not earlier than 120 days prior to such annual
    meeting and not later than the last to occur of the close of
    business on (1) the 90th day prior to such annual
    meeting or (2) the 10th day following the day on which
    Dawson first makes public announcement of the date of such
    meeting by (A) a mailing to shareholders, (B) a press
    release or (C) a filing with the SEC pursuant to
    Section 13(a) or 14(a) of the Exchange Act.  To be
    timely in connection with elections of directors at a special
    meeting of the shareholders, such notice, setting forth the name
    of the person to be nominated, must be delivered to or mailed
    and received at Dawsons principal executive offices not
    less than 40 days nor more than 60 days prior to the
    date of such meeting; provided, however, that in the event that
    less than 47 days notice or prior public disclosure
    of the date of the special meeting of the shareholders is given
    or made to the shareholders, the nominators notice to be
    timely must be so received not later than the close of business
    on the seventh day following the day on which such notice of
    date of the meeting was mailed or such public disclosure was
    made.

Nominations by shareholders of persons for election to the board
    of directors may be made at an annual meeting of shareholders by
    any shareholder of record in accordance with the proper notice
    provisions. For a
    nomination to be properly made by a shareholder, the record
    shareholders notice of nomination must be received by the
    Secretary at the principal executive offices of the corporation
    not less than 60 or more than 90 days prior to the one-year
    anniversary of the date on which the corporation first mailed
    its proxy materials for the preceding years annual meeting
    of shareholders; provided, however, that if the meeting is
    convened more than 30 days prior to, or delayed by more
    than 30 days after, the anniversary of the preceding
    years annual meeting, or if no annual meeting was held in
    the preceding year, notice by the record shareholder to be
    timely must be so received not later than the close of business
    on the later of: (1) the 90th day before such annual
    meeting; or (2) the 10th day following the day on which
    public announcement of the date of such meeting is first made.
    
    Notwithstanding anything in the preceding sentence to the
    contrary, in the event that the number of directors to be
    elected to the TGC board of directors is increased, and there
    has been no public announcement naming all of the nominees for
    director or indicating the increase in the size of the board of
    directors made by the corporation at least ten days before the
    last day a record shareholder may deliver a notice of nomination
    in accordance with the preceding sentence, a record
    shareholders notice herein required shall also be
    considered timely, but only with respect to nominees for any new
    positions created by such  increase, if it is received by the
    Secretary at the principal executive offices of the corporation
    not later than the close of business on the 10th day
    following the day on which such public announcement was first
    made by the corporation.  In no event may an adjournment, or
    postponement of an annual meeting for which notice has been
    given, commence a new time period for the giving of a record
    shareholders notice.A nominator must also submit written evidence, reasonably
    satisfactory to the Secretary, that the 130




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Dawson

TGCnominator is a shareholder of Dawson and must identify in
    writing (1) the name and address of the nominator,
    (2) the number of shares of each class of capital stock of
    Dawson owned beneficially by the nominator, (3) the name
    and address of each of the persons with whom the nominator is
    acting in concert, (4) the number of shares of capital
    stock beneficially owned by each such person with whom the
    nominator is acting in concert, and (5) a description of
    all arrangements or understandings between the nominator and
    each nominee and any other persons with whom the nominator is
    acting in concert pursuant to which the nomination or
    nominations are to be made. The nominator must also submit in
    writing (1) the information with respect to each such
    proposed nominee that would be required to be provided in a
    proxy statement prepared in accordance with Regulation 14A
    under the Exchange Act and (2) a notarized affidavit
    executed by each such proposed nominee to the effect that, if
    elected as a member of the Dawson board of directors, he will
    serve and that he is eligible for election as a member of the
    Dawson board of directors.Shareholder ProposalsAt any annual meeting of shareholders, only such business shall
    be conducted as shall be a proper subject for the meeting and
    shall have been properly brought before the meeting. To be
    properly brought before an annual meeting of shareholders,
    business must (1) be specified in the notice of such
    meeting (or any supplement thereto) given by or at the direction
    of the Dawson board of directors (or any duly authorized
    committee thereof), (2) otherwise be properly brought
    before the meeting by or at the direction of the chairman of the
    meeting or the board of directors (or any duly authorized
    committee thereof) or (3) otherwise (A) be properly
    requested to be brought before the meeting by a shareholder of
    record entitled to vote in the election of directors generally,
    and (B) constitute a proper subject to be brought before
    such meeting.  Any
    shareholder who intends to bring any matter (other than a matter
    relating to (1) any nomination of directors or (2) any
    alteration, amendment or repeal of the bylaws or any adoption of
    new bylaws) before an annual meeting of shareholders and is
    entitled to vote on such matter must deliver written notice of
    such shareholders intent to bring such matter before the
    annual meeting of shareholders, either by personal delivery or
    by United States mail, postage prepaid, to the Secretary.

The proposal by shareholders of business to be transacted by the
    shareholders  may be made at an annual meeting of
    shareholders. For
    business to be properly brought before an annual meeting by a
    record shareholder, (1) the record shareholder must have given
    timely notice thereof in writing to the Secretary; and (2) any
    such business must be a proper matter for shareholder action
    under Texas law.  To be
    timely, a record shareholders notice must be received by
    the Secretary at TGCs principal executive offices not less
    than 60 or more than 90 days prior to the one-year
    anniversary of the date on which the corporation first mailed
    its proxy materials for the preceding years annual meeting
    of shareholders; provided, however, that if the meeting is
    convened more than 30 days prior to, or delayed by more
    than 30 days after, the anniversary of the preceding
    years annual meeting, or if no annual meeting was held in
    the preceding year, notice by the record shareholder to be
    timely must be so received not later than the close of business
    on the later of: (1) the 90th day before such annual
    meeting; or (2) the 10th day following the day on which
    public announcement of the date of such meeting is first made.Such notice must be received by the Secretary not less than
    90 days nor more than 120 days prior to the first
    anniversary of the date on which the immediately 131




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Dawson

TGCpreceding years annual meeting of shareholders was held;
    provided, however, that if the date of the annual meeting is
    advanced more than 30 days prior to or delayed by more than
    60 days after the first anniversary of the preceding
    years annual meeting, notice by the shareholder to be
    timely must be so delivered not earlier than 120 days prior
    to such annual meeting and not later than the last to occur of
    the close of business on (1) the 90th day prior to
    such annual meeting or (2) the 10th day following the
    day on which the Corporation first makes public announcement of
    the date of such meeting by (A) a mailing to shareholders,
    (B) a press release or (C) a filing with the SEC
    pursuant to Section 13(a) or 14(a) of the Securities and
    Exchange Act.IndemnificationDawsons amended and restated bylaws, as amended, provide
    for mandatory indemnification, to the fullest extent permitted
    by Texas law, of each person who is or was made a party or is
    threatened to be made a party to or involved in any actual or
    threatened action, suit or proceeding because the person is or
    was an officer, director, employee or agent of Dawson.

TGCs restated articles of incorporation and amended and
    restated bylaws provide for mandatory indemnification to the
    fullest extent permitted by Texas law, of each person who is or
    was made a party or is threatened to be made a party to or
    involved in any actual or threatened civil, criminal,
    administrative or investigative action, suit or proceeding
    because the person is or was an officer or director of TGC or
    served at the request of TGC as a director, officer, employee or
    agent of another corporation or of a partnership, joint venture,
    trust or other enterprise.Amendments to Articles of IncorporationAmendment of the second restated articles of incorporation
    requires the approval of (1) the Dawson board of directors
    and (2) the holders of at least two-thirds of the
    outstanding shares entitled to vote upon the proposed amendment.

Generally, amendment of the restated articles of incorporation
    requires the approval of (1) the TGC board of directors and (2)
    the holders of at least two-thirds of the outstanding shares
    entitled to vote upon the proposed amendment. 
    However, approval of the holders of at least 80% of the
    outstanding shares entitled to vote upon the proposed amendment
    is required to amend or repeal Article 7 of the restated
    articles of incorporation.Amendments to BylawsDawsons amended and restated bylaws may be altered or
    repealed at any regular or special meeting at which a quorum is
    present or represented, by the affirmative vote of a majority of
    the shares entitled to vote at such meeting or by the
    affirmative vote of a majority of the Dawson board of directors
    at any regular or special meeting of the board.

TGCs amended and restated bylaws may be altered or
    repealed at any regular or special meeting at which a quorum is
    present or represented, by the affirmative vote of a majority of
    the TGC board of directors.  This power is subject to repeal or
    change by action of TGC shareholders.  132




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EXPERTS  Dawson
    TGC
   133




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UNAUDITED
    PRO FORMA CONDENSED COMBINED CONSOLIDATED
    FINANCIAL INFORMATION     
  Form 10-K Form 10-Q
 
  and/or
     134




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10-day
   135




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UNAUDITED
    PRO FORMA CONDENSED COMBINED CONSOLIDATED BALANCE SHEETAS OF MARCH 31, 2011
  Pro FormaHistorical


Pro Forma




CondensedDawson


TGC


Adjustments




CombinedASSETSCurrent assets:Cash and cash equivalents

$
13,602,000


$
15,466,000


$





$
29,068,000Short-term investments


5,500,000













5,500,000Accounts receivable, net of allowance for doubtful accounts


68,704,000



27,694,000



3,147,000


(a)(d)


99,545,000Cost and estimated earning in excess of billings on uncompleted
    contracts






2,859,000



(2,859,000
)

(d)


Prepaid expenses and other assets


11,951,000



726,000



(82,000
)

(a)(b)


12,595,000Current deferred tax asset


1,795,000







471,000


(e)(g)


2,266,000Total current assets


101,552,000



46,745,000



677,000





148,974,000Property, plant and equipment


280,511,000



134,117,000



(60,634,000
)

(f)


353,994,000Less accumulated depreciation


(141,449,000
)


(80,979,000
)


80,979,000


(f)


(141,449,000
)Net property, plant and equipment


139,062,000



53,138,000



20,345,000





212,545,000Other assets






63,000



(63,000
)

(b)


Oil and gas interest










361,000


(h)


361,000Intangible










22,850,000


(i)


22,850,000Goodwill






202,000



39,087,000


(j)


39,289,000Total assets

$
240,614,000


$
100,148,000


$
83,257,000




$
424,019,000LIABILITIES AND STOCKHOLDERS EQUITYCurrent liabilities:Accounts payable

$
19,748,000


$
13,470,000


$
2,998,000


(c)(m)

$
36,216,000Accrued liabilities:






3,326,000



(3,326,000
)

(c)


Payroll costs and other taxes


4,231,000







1,815,000


(c)


6,046,000Other


8,426,000







2,121,000


(c)(e)


10,547,000Deferred revenue


3,994,000







7,312,000


(d)


11,306,000Billings in excess of costs and estimated earnings on
    uncompleted contracts






5,810,000



(5,810,000
)

(d)


Federal and state income taxes payable






2,048,000



(2,048,000
)

(e)


Current maturities of notes payable






5,473,000



267,000


(k)


5,740,000Current maturities of capital lease obligations






1,148,000









1,148,000Total current liabilities


36,399,000



31,275,000



3,329,000





71,003,000Non-current liabilities:Notes payable, less current maturities






3,785,000



154,000


(k)


3,939,000Capital lease obligations, less current maturities






1,380,000









1,380,000Long-term deferred tax liability


19,188,000



4,297,000



14,929,000


(g)


38,414,000Commitments and contingencies
















Total non-current liabilities


19,188,000



9,462,000



15,083,000





43,733,000Stockholders equity:Preferred stock
















Common stock


2,640,000



193,000



1,013,000


(l)


3,846,000Additional paid-in capital


91,730,000



27,567,000



97,043,000


(l)


216,340,000Accumulated other comprehensive income, net of tax






1,478,000



(1,478,000
)




Retained earnings


90,657,000



30,430,000



(31,990,000
)

(d)(m)


89,097,000Treasury stock






(257,000
)


257,000


(l)


Total stockholders equity


185,027,000



59,411,000



64,845,000





309,283,000Total liabilities and stockholders equity

$
240,614,000


$
100,148,000


$
83,257,000




$
424,019,000    136




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UNAUDITED
    PRO FORMA CONDENSED COMBINED CONSOLIDATED INCOME STATEMENTFOR THE YEAR ENDED SEPTEMBER 30,
    2010
  Historical








Pro FormaDAWSON


TGC


Pro Forma





CondensedYear End


Year End


Adjustments





CombinedOperating revenues

$
205,272,000


$
108,319,000


$
10,284,000



(n
)

$
323,875,000Operating costs:Operating expenses


185,588,000



85,933,000



10,387,000



(n
)


281,908,000General and administrative


7,131,000



6,894,000











14,025,000Depreciation and amorization


27,126,000



15,344,000



2,547,000



(o
)


45,017,000219,845,000



108,171,000



12,934,000







340,950,000(Loss) income from operations


(14,573,000
)


148,000



(2,650,000
)






(17,075,000
)Other income (expense):Interest income


185,000















185,000Interest expense






(791,000
)


328,000



(q
)


(463,000
)Other income


398,000















398,000Loss before income tax


(13,990,000
)


(643,000
)


(2,322,000
)






(16,955,000
)Income tax benefit (expense):Current


7,102,000



(433,000
)


(96,000
)


(p
)


6,573,000Deferred


(2,464,000
)


(147,000
)


951,000



(p
)


(1,660,000
)4,638,000



(580,000
)


855,000







4,913,000Net loss

$
(9,352,000
)

$
(1,223,000
)

$
(1,467,000
)





$
(12,042,000
)Basic loss per common share

$
(1.20
)

$
(0.06
)









$
(1.06
)Diluted loss per common share

$
(1.20
)

$
(0.06
)









$
(1.06
)Weighted average equivalent common shares outstanding


7,777,404



19,202,804











11,394,309Weighted average equivalent common shares outstanding- assuming
    dilution


7,777,404



19,202,804











11,394,309    137




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UNAUDITED
    PRO FORMA CONDENSED COMBINED CONSOLIDATED INCOME STATEMENTFOR THE SIX MONTHS ENDED MARCH 31,
    2011
  Historical








Pro FormaDAWSON


TGC


Pro Forma





Condensed3/31/11


3/31/11


Adjustments





CombinedOperating revenues

$
150,990,000


$
82,948,000


$
6,211,000



(n
)

$
240,149,000Operating costs:Operating expenses


139,893,000



59,348,000



6,286,000



(n
)


205,527,000General and administrative


5,592,000



4,387,000



(1,560,000
)


(r
)


8,419,000Depreciation and amortization


14,867,000



8,286,000



435,000



(o
)


23,588,000160,352,000



72,021,000



5,161,000







237,534,000(Loss) income from operations


(9,362,000
)


10,927,000



1,050,000







2,615,000Other income (expense):Interest income


31,000















31,000Interest expense






(365,000
)


234,000



(q
)


(131,000
)Other income


582,000















582,000(Loss) income before income tax


(8,749,000
)


10,562,000



1,284,000







3,097,000Income tax benefit (expense)


2,225,000



(4,090,000
)


125,000



(p
)


(1,740,000
)Net (loss) income

$
(6,524,000
)

$
6,472,000


$
1,409,000






$
1,357,000Basic (loss) income per common share

$
(0.84
)

$
0.34










$
0.12Diluted (loss) income per common share

$
(0.84
)

$
0.33










$
0.12Weighted average equivalent common shares outstanding


7,793,836



19,209,084











11,410,741Weighted average equivalent common shares outstanding- assuming
    dilution


7,793,836



19,498,771











11,568,299    138




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##### Table of Contents



NOTES TO
    UNAUDITED PRO FORMA CONDENSED COMBINED
    CONSOLIDATED FINANCIAL INFORMATION
  1.
    Basis of
    Presentation  805-10, Business Combinations  Overall, ASC 805-10. ASC 805-10,
  ASC 805-10.
  820-10, Fair Value Measurement and Disclosure 
    Overall, ASC 820-10, ASC 820-10 ASC 820-10,
  ASC 805-10,
   139




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##### Table of Contents



NOTES TO
    UNAUDITED PRO FORMA CONDENSED COMBINED
    CONSOLIDATED FINANCIAL
    INFORMATION  (Continued)
        2.
    Accounting
    Policies    
    Dawson records third party reimbursable amounts billed to
    clients at the gross amount as a component of operating revenues
    and expenses in our statement of operations and as accounts
    receivable and accounts payable in the balance sheet. TGC does
    not reflect these reimbursed charges on their statement of
    operations and records them as a component of costs in excess of
    billings in the balance sheet. See Note 5: item (d) below.
    Dawson uses longer estimated useful lives than TGC for its
    recording and vibroseis equipment when calculating depreciation
    expense.
    Dawson records all internal labor as incurred in operating
    expenses in the statement of operations, while TGC records
    certain departmental costs pro rata as revenues are recognized.
    See Note 5: item (d) below.  3.
    Estimate
    of Consideration Expected to be Transferred    Conversion


Estimated FairCalculation


ValueNumber of shares of TGC common stock outstanding as of
    May 13, 2011






19,238,856Multiplied by the exchange ratio of 0.188, multiplied by
    Dawsons average high and low price as of May 13, 2011
    of $34.12


3,616,905


$
123,409,000Fair value of vested stock options pertaining to pre-merger
    service to be assumed by Dawson(a)






2,407,000Estimate of consideration expected to be transferred(b)





$
125,816,000     (a)
    
    Represents the fair value of TGCs stock options for
    pre-merger services.
    ASC 805-10
    requires that the fair value of awards assumed attributable to
    pre-merger service be included in the consideration transferred.
    The fair value of TGCs stock options was estimated as of
    May 13, 2011 to be $2,407,000 using the Black-Scholes
    valuation model utilizing the assumptions noted below. 140




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##### Table of Contents



NOTES TO
    UNAUDITED PRO FORMA CONDENSED COMBINED
    CONSOLIDATED FINANCIAL
    INFORMATION  (Continued)
   Assumptions
    used for the valuation of TGCs stock options:
  Stock Price

$6.31Original Grant Price

$3.78Expected Term

2.2 yearsExpected Volatility

61.11%Risk free interest rate

0.65%Expected dividend yield

  The expected volatility of TGCs stock price is based on
    average historical volatility which is based on observations and
    a duration consistent with the expected life assumption. The
    weighted average expected life of the options are calculated
    using the simplified method by using the options
    expiration date. The risk-free interest rate is based on
    U.S. treasury securities with maturities equal to the
    expected life of the options.(b)
    
    The estimated consideration expected to be transferred reflected
    in the unaudited pro forma condensed combined consolidated
    financial information does not purport to represent what the
    actual consideration transferred will be when the merger is
    completed. In accordance with
    ASC 805-10,
    the fair value of equity securities issued as part of the
    consideration transferred will be measured on the closing date
    of the merger at the then-current market price. This requirement
    will likely result in a per share equity component different
    from the $34.12 assumed in the unaudited pro forma condensed
    combined consolidated financial information and that difference
    may be material. Assuming a $1.00 change in Dawsons
    closing common stock price, the estimated consideration
    transferred excluding any value associated with stock options
    assumed by Dawson would increase or decrease by approximately
    $3.6 million, which would be reflected in the unaudited pro
    forma condensed combined consolidated financial information as
    an increase or decrease to goodwill.  4.
    Estimate
    of the Assets to be Acquired and Liabilities to be
    Assumed    (In thousands)Book value of net assets acquired at March 31, 2011

$
59,411Less: TGCs historical goodwill


(202
)Adjusted book value of net assets acquired

$
59,209Adjustments to:Accounts receivables and deferred revenue

$
(1,359
)Property, plant and equipment


20,345Intangible assets


22,850Oil and gas interest


361Notes payable


(421
)Current/deferred taxes


(14,458
)Goodwill


39,289Total adjustments

$
66,607Estimate of consideration expected to be transferred

$
125,816    141




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##### Table of Contents



NOTES TO
    UNAUDITED PRO FORMA CONDENSED COMBINED
    CONSOLIDATED FINANCIAL
    INFORMATION  (Continued)
  Property, plant and equipment: held-for-sale
  Intangible assets:
      Weighted-AverageEstimated


EstimatedFair Value


Useful LifeTrademarks

$
7,448







10 yearsCustomer relationships


13,162







15 yearsOther intangible assets


2,240







1 year$
22,850     and/or
 142




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##### Table of Contents



NOTES TO
    UNAUDITED PRO FORMA CONDENSED COMBINED
    CONSOLIDATED FINANCIAL
    INFORMATION  (Continued)
  and/or
  Notes payable:
  Deferred income tax liabilities:
      Goodwill:
 143




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##### Table of Contents



NOTES TO
    UNAUDITED PRO FORMA CONDENSED COMBINED
    CONSOLIDATED FINANCIAL
    INFORMATION  (Continued)
    5.
    Reclassifications    Item (a):
  Item (b):
  Item (c):
  Item (d):
  Item (e):
  6.
    Adjustments
    to Unaudited Pro Forma Condensed Combined Balance
    Sheet  Item (f):
  Item (g):
  Item (h):
  Item (i):
 144




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##### Table of Contents



NOTES TO
    UNAUDITED PRO FORMA CONDENSED COMBINED
    CONSOLIDATED FINANCIAL
    INFORMATION  (Continued)
    Item (j):
  Item (k):
  Item (l):
  Item (m):
  7.
    Adjustments
    to Unaudited Pro Forma Condensed Combined Statements of
    Income  Item (n):
  Item (o):
  Item (p):
  Item (q):
  Item (r):
 145




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##### Table of Contents



LEGAL
    MATTERS   146




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##### Table of Contents



DATES FOR
    SUBMISSION OF SHAREHOLDER PROPOSALS FOR THE 2011 ANNUAL
    MEETINGS Dawson  Inclusion
    of Proposals in Dawsons Proxy Statement and Proxy Card
    under the SECs Rules
    Bylaw
    Requirements for Shareholder Submissions of Nominations and
    Proposals
     
  www.sec.gov.
 
 TGC  Inclusion
    of Proposals in TGCs Proxy Statement and Proxy Card under
    the SECs Rules
   147




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##### Table of Contents



Bylaw
    Requirements for Shareholder Submissions of Nominations and
    Proposals
      Rule 14a-8 Rule 14a-4(c),
 
   
 148




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##### Table of Contents



HOUSEHOLDING
    OF JOINT PROXY STATEMENT/PROSPECTUS    (432) 684-3000 (972) 881-1099.
 149




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##### Table of Contents



WHERE YOU
    CAN FIND MORE INFORMATION  Form S-4
  1-800-SEC-0330 http://www.sec.gov http://www.dawson3d.com http://www.tgcseismic.com
      Dawson
  
    Annual Report on
    Form 10-K
    for the fiscal year ended September 30, 2010;
    Quarterly Reports on
    Form 10-Q
    for the quarters ended December 31, 2010 and March 31,
    2011;
    Definitive Proxy Statement filed with the SEC on
    December 7, 2010; 
  
    Current Reports on
    Form 8-K
    filed with the SEC on October 1, 2010, November 19,
    2010, January 21, 2011, March 21, 2011, May 4,
    2011, May 5, 2011, June 2, 2011, June 23, 2011
    and July 7, 2011 (in each case only to the extent filed and
    not furnished); and 
  
    the description of Dawson common stock contained in
    Dawsons Registration Statement on
    Form 8-A
    filed on February 1, 1982, as amended by
    Form 8-A/A
    filed on March 8, 1982 and as thereafter amended from time
    to time for the purpose of updating, changing or modifying such
    description, and the description of Dawsons rights to
    purchase Series A Junior Participating Preferred Stock on
    Form 8-A
    filed on July 9, 2009 and as thereafter amended from time
    to time for the purpose of updating, changing or modifying such
    description.  TGC
  
    Annual Report on
    Form 10-K
    for the fiscal year ended December 31, 2010;
    Amended Annual Report on
    Form 10-K/A
    for the year ended December 31, 2010;
    Quarterly Report on
    Form 10-Q
    for the quarter ended March 31, 2011;
    Current Reports on
    Form 8-K
    filed with the SEC on March 21, 2011, June 2, 2011 and
    June 9, 2011; and
    the description of TGC common stock contained on
    Form 8-K
    filed with the SEC on June 9, 2011. 150




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##### Table of Contents



Form 10-K, Form 10-Q Form 8-K.
    Dawson Geophysical Company
    508 West Wall, Suite 800
    Midland, Texas 79701
    Attention: Investor Relations
    Telephone:
    (432) 684-3000

TGC Industries, Inc.
    101 East Park Blvd., Suite 955
    Plano, Texas 75074
    Attention: Investor Relations
    Telephone: (972) 881-1099          151




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##### Table of Contents



ANNEX A     AGREEMENT
    AND PLAN OF MERGER
 among
 DAWSON GEOPHYSICAL COMPANY,
 6446 ACQUISITION CORP.
 and
 TGC INDUSTRIES, INC.
 Dated as of March 20, 2011
      A-1




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##### Table of Contents



TABLE OF
    CONTENTS
  ARTICLE I. THE MERGER


A-8Section 1.1

The Merger


A-8Section 1.2

The Closing


A-9Section 1.3

Effective Time


A-9ARTICLE II.
    GOVERNING DOCUMENTS


A-9Section 2.1

Articles of Incorporation of the Surviving Entity


A-9Section 2.2

Bylaws of the Surviving Entity


A-9ARTICLE III.
    DIRECTORS AND OFFICERS OF THE SURVIVING ENTITY


A-9Section 3.1

Board of Directors of Surviving Entity


A-9Section 3.2

Officers of Surviving Entity


A-9Section 3.3

Governance Matters


A-9ARTICLE IV.
    CONVERSION OF COMPANY COMMON STOCK


A-10Section 4.1

Conversion of Capital Stock of the Company and Merger Sub


A-10Section 4.2

Exchange of Certificates Representing Company Common Stock


A-12Section 4.3

Adjustment of Exchange Ratio


A-14ARTICLE V.
    REPRESENTATIONS AND WARRANTIES OF THE COMPANY


A-15Section 5.1

Existence; Good Standing; Corporate Authority


A-15Section 5.2

Authorization, Validity, Enforceability and Fairness


A-15Section 5.3

Capitalization


A-16Section 5.4

Subsidiaries


A-16Section 5.5

No Conflict


A-17Section 5.6

SEC Documents; Financial Statements


A-17Section 5.7

Internal Controls and Procedures


A-18Section 5.8

Compliance with Laws; Permits


A-19Section 5.9

Litigation


A-19Section 5.10

Absence of Certain Changes


A-20Section 5.11

Taxes


A-21Section 5.12

Employee Benefit Plans


A-22Section 5.13

Labor and Employee Matters


A-24Section 5.14

Environmental Matters


A-25Section 5.15

Properties


A-26Section 5.16

Intellectual Property


A-26Section 5.17

Insurance


A-27Section 5.18

Certain Contracts


A-27Section 5.19

Government Contracts


A-28Section 5.20

No Brokers


A-28Section 5.21

Parent Stock Ownership


A-29Section 5.22

Vote Required


A-29Section 5.23

Improper Payments


A-29Section 5.24

Takeover Statutes; Rights Agreement


A-29Section 5.25

Interested Party Transactions


A-30 A-2




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##### Table of Contents



ARTICLE VI.
    REPRESENTATIONS AND WARRANTIES OF PARENT AND MERGER SUB


A-30Section 6.1

Existence; Good Standing; Corporate Authority


A-30Section 6.2

Authorization, Validity, Enforceability and Fairness


A-30Section 6.3

Capitalization


A-31Section 6.4

Subsidiaries


A-32Section 6.5

No Conflict


A-32Section 6.6

SEC Documents; Financial Statements


A-32Section 6.7

Disclosure and Internal Controls and Procedures


A-33Section 6.8

Compliance with Laws; Permits


A-34Section 6.9

Litigation


A-34Section 6.10

Absence of Certain Changes


A-34Section 6.11

Taxes


A-35Section 6.12

Employee Benefit Plans


A-36Section 6.13

Labor and Employee Matters


A-38Section 6.14

Environmental Matters


A-39Section 6.15

Properties


A-40Section 6.16

Intellectual Property


A-40Section 6.17

Insurance


A-41Section 6.18

Certain Contracts


A-41Section 6.19

Government Contract


A-42Section 6.20

No Brokers


A-42Section 6.21

Company Stock Ownership


A-42Section 6.22

Vote Required


A-42Section 6.23

Improper Payments


A-42Section 6.24

Affiliate Transactions


A-43ARTICLE VII.
    COVENANTS


A-43Section 7.1

Conduct of Business by the Company


A-43Section 7.2

Conduct of Business by Parent


A-46Section 7.3

No Solicitation


A-48Section 7.4

Preparation of Proxy Statement; Meetings of Shareholders


A-51Section 7.5

Filings; Reasonable Best Efforts


A-52Section 7.6

Inspection


A-53Section 7.7

Publicity


A-53Section 7.8

Listing Application


A-54Section 7.9

Section 16 Matters


A-54Section 7.10

Expenses


A-54Section 7.11

Indemnification and Insurance


A-54Section 7.12

Antitakeover Statutes


A-54Section 7.13

Notification


A-54Section 7.14

Employee Matters


A-55Section 7.15

Other Pre-Closing Matters


A-56Section 7.16

Shareholder Litigation


A-56Section 7.17

Tax Treatment


A-56 A-3




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##### Table of Contents



ARTICLE VIII.
    CONDITIONS


A-56Section 8.1

Conditions to Each Partys Obligation to Effect the Merger


A-56Section 8.2

Conditions to Obligation of the Company to Effect the Merger


A-57Section 8.3

Conditions to Obligation of Parent and Merger Sub to Effect the
    Merger


A-58Section 8.4

Frustration of Conditions


A-58ARTICLE IX.
    TERMINATION


A-58Section 9.1

Termination by Mutual Consent


A-58Section 9.2

Termination by Parent or the Company


A-58Section 9.3

Termination by the Company


A-59Section 9.4

Termination by Parent


A-59Section 9.5

Effect of Termination


A-60Section 9.6

Extension; Waiver


A-62ARTICLE X. GENERAL
    PROVISIONS


A-62Section 10.1

Nonsurvival of Representations, Warranties and Agreements


A-62Section 10.2

Notices


A-63Section 10.3

Assignment; Binding Effect; Benefit


A-63Section 10.4

Entire Agreement


A-63Section 10.5

Amendments


A-64Section 10.6

Governing Law


A-64Section 10.7

Headings


A-64Section 10.8

Definitions and Interpretation


A-64Section 10.9

Severability


A-66Section 10.10

Enforcement of Agreement


A-66Section 10.11

Consent to Jurisdiction and Venue; Appointment of Agent for
    Service of Process


A-67Section 10.12

No Recourse


A-67Section 10.13

Counterparts


A-67   ExhibitsExhibit A

Restated Certificate of Formation of Surviving Entity

A-A-1Exhibit B

Bylaws of Surviving Entity

A-B-1Exhibit C

Form of Company Shareholder Voting Agreement

E-1Exhibit D

Form of Parent Shareholder Voting Agreement

D-1Exhibit E

Form of Employment Agreement

F-1Exhibit F

Form of Indemnification Agreement

G-1  A-4




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##### Table of Contents



GLOSSARY
    OF DEFINED TERMS
  Defined Terms

Where DefinedAcquisition Proposal

Section 7.3(f)(i)Affected Participants

Section 7.14(a)Affiliate

Section 10.8(b)Agreement

PreambleAntitrust Laws

Section 10.8(c)Applicable Law

Section 10.8(d)Average Price

Section 4.1(b)Book Entry Share

Section 4.1(a)Certificate

Section 4.1(a)Certificate of Merger

Section 1.3Change/Intent to Terminate Notice

Section 7.3(b)Closing

Section 1.2Closing Date

Section 1.2Code

RecitalsCompany

PreambleCompany Adverse Recommendation Change

Section 7.3(b)Company Affiliate Transaction

Section 5.25Company Articles of Incorporation

Section 5.1Company Benefit Plans

Section 5.12(a)Company Board

Section 3.3Company Bylaws

Section 5.1Company Common Stock

RecitalsCompany Disclosure Letter

Article VCompany Equity Awards

Section 4.1(f)(i)Company Financial Advisor

Section 5.2(e)Company IP

Section 10.8(e)Company Material Adverse Effect

Section 10.8(f)Company Material Contract

Section 5.18(a)(viii)Company Options

Section 5.3(c)Company Permits

Section 5.8(b)Company Preferred Stock

Section 5.3(a)Company Qualified Plans

Section 7.14(e)Company Recommendation

Section 5.2(d)Company Registered IP

Section 5.16(a)Company Reports

Section 5.6(a)Company Restricted Stock Award

Section 4.1(f)(ii)Company Stock Option Award

Section 4.1(f)(iii)Company Stock Plans

Section 4.1(f)(i)Company Shareholder Approval

Section 5.22Company Shareholder Voting Agreement

RecitalsCompany Shareholders Meeting

Section 7.4(e)Company Voting Shareholders

RecitalsConfidentiality Agreement

Section 7.3(a) A-5




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##### Table of Contents



Defined Terms

Where DefinedContract

Section 10.8(g)Continuing Employees

Section 7.14(a)Debt

Section 10.8(h)Designated Director

Section 3.3Effective Time

Section 1.3Environmental Laws

Section 5.14(a)Equity Award Restrictive Covenants

Section 4.1(f)(vii)ERISA

Section 5.12(a)ERISA Affiliate

Section 5.12(a)Exchange Act

Section 5.5(b)Exchange Agent

Section 4.2(a)Exchange Fund

Section 4.2(a)Exchange Ratio

Section 4.1(a)Existing Indemnification Agreements

Section 7.11(c)Fairness Opinion

Section 5.2(e)Foreign Corrupt Practices Act

Section 5.23(a)Foreign Government Official

Section 5.23(a)Form S-4

Section 7.4(a)GAAP

Section 10.8(i)Governmental Authority

Section 10.8(j)Government Contract

Section 5.19Hazardous Materials

Sections 5.14(a)HSR Act

Section 5.5(b)Intellectual Property

Section 10.8(k)Letter of Transmittal

Section 4.2(b)Lien

Section 5.4(a)Material Adverse Effect

Section 10.8(l)Merger

RecitalsMerger Consideration

Section 4.1(a)Merger Sub

PreambleNASDAQ

Section 5.5(b)No-Shop Party

Section 7.3(a)Other Party

Section 7.3(a)Parent

PreambleParent Adverse Recommendation Change

Section 7.3(b)Parent Affiliate Transaction

Section 6.23Parent Articles of Incorporation

Section 6.1Parent Board

Section 3.3Parent Common Stock

RecitalsParent Disclosure Letter

Article VIParent Equity Awards

Section 6.3(a)Parent Financial Advisor

Section 6.2(e)Parent IP

Section 10.8(m)Parent Material Adverse Effect

Section 10.8(n) A-6




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##### Table of Contents



Defined Terms

Where DefinedParent Material Contract

Section 6.18(a)(viii)Parent Options

Section 6.3(c)Parent Permits

Section 6.8(b)Parent Recommendation

Section 6.2(d)Parent Registered IP

Section 6.16(a)Parent Reports

Section 6.6(a)Parent Stock Plan

Section 6.3(a)Parent Shareholder Approval

Section 6.22Parent Shareholder Voting Agreement

RecitalsParent Shareholders Meeting

Section 7.4(f)Parent Voting Shareholders

RecitalsPermitted Liens

Section 10.8(o)Post-Closing Plan

Section 7.14(e)Person

Section 10.8(p)Price Determination Date

Section 4.1(b)Proceeding

Section 10.8(q)Proxy Statement/Prospectus

Section 7.4(a)Reconfirmation Opinion

Section 7.15(b)Regulatory Filings

Section 5.5(b)Related Persons

Section 9.5(g)Representatives

Section 10.8(r)Returns

Section 5.11(a)Rollover Awards

Section 4.1(f)(iii)Sarbanes-Oxley Act

Section 5.7(a)SEC

Section 4.1(f)(vi)Securities Act

Section 5.5(b)Special Valuation Proposal

Section 7.3(f)(ii)Subsidiary

Section 10.8(s)Superior Acquisition Proposal Termination

Section 7.3(b)Superior Proposal

Section 7.3(f)(iii)Surviving Entity

Section 1.1Tax or Taxes

Section 10.8(t)TBOC

Section 1.1Termination Date

Section 9.2(a)Treasury Regulations

RecitalsUltimate Price Event

Section 4.1(b)VEBA

Section 5.12(a)  A-7




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##### Table of Contents



AGREEMENT
    AND PLAN OF MERGER
  Agreement Parent Merger Sub Company
  RECITALS
  The Merger. Merger Company Common Stock Parent Common
    Stock
  Intended U.S. Tax
    Consequences. Code Treasury
    Regulations
  Voting Agreements. Company
    Voting Shareholders Exhibit C Company Shareholder
    Voting Agreement Parent Voting Shareholders Exhibit D Parent Shareholder Voting Agreement
    ARTICLE I.
  THE MERGER
  Section The
    Merger. Surviving Entity TBOC
 A-8




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##### Table of Contents



Section The
    Closing. Closing Closing Date
  Section Effective
    Time. Certificate of Merger Effective Time
  ARTICLE II.
  GOVERNING
    DOCUMENTS
  Section Articles
    of Incorporation of the Surviving Entity. Exhibit A
  Section Bylaws
    of the Surviving Entity. Exhibit B
  ARTICLE III.
  DIRECTORS
    AND OFFICERS OF THE SURVIVING ENTITY
  Section Board
    of Directors of Surviving Entity. Section 3.1
  Section Officers
    of Surviving Entity.
  Section Governance
    Matters. Parent Board Company Board Section 3.3 Designated Director
 A-9




---



##### Table of Contents



ARTICLE IV.
  CONVERSION
    OF COMPANY COMMON STOCK
  Section Conversion
    of Capital Stock of the Company and Merger Sub
  Merger Consideration. Section 4.1(d) Section 4.1(b) Exchange
    Ratio Section 4.2(e) Merger
    Consideration Section 4.2 Certificate Book Entry Share
  Determination of Exchange
    Ratio. Section 7.4 Price Determination Date provided, however, Ultimate Price Event Section 9.2(e)
  Section 4.1(b) Average Price The Wall Street Journal
  Cancellation of Shares of Company Common
    Stock. Section 4.1(d) Section 4.2(c)
  Cancellation of Remaining Shares of Company
    Common Stock.
  Conversion of Merger Sub Common
    Stock.
  Treatment of Company Equity Awards.
  Company Equity
    Awards Company Stock Plans
 A-10




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##### Table of Contents



Section 4.1(f)
  Company Restricted Stock Award
  30-day Company Stock Option Award 30-day Rollover Awards provided, however
  Section 4.1(f) provided, however provided
  Section 4.1(f)(v) Section 4.1(f)(v)
 A-11




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##### Table of Contents



SEC Form S-8 Section 4.1(f) Section 4.1(f)
  Section 4.1(f) Equity Award Restrictive
    Covenants
  Section Exchange
    of Certificates Representing Company Common Stock
  Exchange Fund. Exchange
    Agent Section 4.2(e) Section 4.2(c) Exchange
    Fund
  Exchange Procedures. Letter of Transmittal Section 4.2(c) Section 4.2(i) Section 4.1(a) Section 4.2(e)
 A-12




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##### Table of Contents



Section 4.2(i)
  Distributions with Respect to Unexchanged
    Shares. Section 4.1
  No Further Ownership Rights in Company Common
    Stock; Closing of Transfer Books. Section 4.2(e) Section 4.2(c)
  No Fractional Shares.
    and/or The Wall Street Journal
 A-13




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##### Table of Contents



Termination of Exchange
    Fund.
  No Liability.
  Lost Certificates. Section 4.2(c)
  Parent Book Entry
    Shares.
  Investment of the Exchange
    Fund. provided
  Further Assurances.
  Section Adjustment
    of Exchange Ratio.
 A-14




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##### Table of Contents



ARTICLE V.
  REPRESENTATIONS
    AND WARRANTIES OF THE COMPANY
  Company Disclosure Letter provided Sections 5.1 5.2 5.3 5.4 5.6 Section 5.10
  Section Existence;
    Good Standing; Corporate Authority. Company Articles of
    Incorporation Company Bylaws
  Section Authorization,
    Validity, Enforceability and Fairness
        Company Recommendation Section 7.3 Sections 7.3 7.4
  Company Financial Advisor
 A-15




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##### Table of Contents



Fairness
    Opinion
  Section Capitalization
  Company Preferred Stock
  Section 5.3(a) Section 5.3(b)
  Company Options
  Section Subsidiaries
  Section 5.4
 A-16




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##### Table of Contents



Lien
      Section No
    Conflict
  Section 5.5(b)
  Hart-Scott-Rodino HSR
    Act Securities Act Exchange Act NASDAQ
  Section SEC
    Documents; Financial Statements
   A-17




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##### Table of Contents



Company Reports
  Form 10-Q
    Section Internal
    Controls and Procedures
  Sarbanes-Oxley Act
      Rule 13a-15(e) 15d-15(e) Rule 13a-15
 A-18




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##### Table of Contents



Rule 13a-15(f) 15d-15(f) Form 10-K
    Section Compliance
    with Laws; Permits
    Company Permits
  Section Litigation
  Section 5.9(a)
   A-19




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##### Table of Contents



Section Absence
    of Certain Changes.
                      Section 5.10(k)
 A-20




---



##### Table of Contents



Section Taxes
  Returns
     A-21




---



##### Table of Contents



Section 1.6011-4 2002-2, 2002-2
        Section 5.11(g)
    Section Employee
    Benefit Plans
  Section 5.12(a) Company
    Benefit Plans ERISA U.S.-based VEBA U.S.-based ERISA Affiliate
  non-U.S. based non-U.S. based
 A-22




---



##### Table of Contents



non-U.S. based
  non-U.S. jurisdictions non-U.S. based
    2005-1
         A-23




---



##### Table of Contents



non-U.S. law),
  non-U.S. law,
  non-U.S. based non-U.S. plan non-U.S. plan non-U.S. plan
  Section Labor
    and Employee Matters
  Section 5.13(a) and/or
   A-24




---



##### Table of Contents



Section Environmental
    Matters
  Environmental Laws Hazardous Materials
     A-25




---



##### Table of Contents



Section 5.14 Section 5.6
  Section Properties
  Form 10-K
        Section 5.15(e)
  Section Intellectual
    Property
  Section 5.16(a) Company Registered IP off-the-shelf-software)
 A-26




---



##### Table of Contents



Section Insurance. Section 5.17 Section 5.17
  Section Certain
    Contracts
  Section 5.18
     A-27




---



##### Table of Contents



Regulation S-K
    Section 5.18(a)(vii)
  Company
    Material Contract
      Section Government
    Contracts. Section 5.19 Section 5.19(a) Government Contract
  Section No
    Brokers.
 A-28




---



##### Table of Contents



Section Parent
    Stock Ownership.
  Section Vote
    Required. Company
    Shareholder Approval
  Section Improper
    Payments
  §§ 78dd-1 Foreign Corrupt Practices
    Act Foreign Government
    Official non-U.S. Governmental non-U.S. Governmental
        Section Takeover
    Statutes; Rights Agreement.
 A-29




---



##### Table of Contents



Section 21.601-21.610
  Section Interested
    Party Transactions. Section 5.25 Company Affiliate
    Transaction
  ARTICLE VI.
  REPRESENTATIONS
    AND WARRANTIES
 OF PARENT
    AND MERGER SUB
  Parent Disclosure Letter provided Sections 6.1 6.2 6.3 6.4 6.6
  Section Existence;
    Good Standing; Corporate Authority. Parent Articles of
    Incorporation
  Section Authorization,
    Validity, Enforceability and Fairness
     A-30




---



##### Table of Contents



Parent Recommendation Section 7.3 Sections 7.3 7.4
  Parent Financial Advisor
  Section Capitalization
  Parent Equity Awards Parent Stock
    Plan
  Section 6.3(a)
 A-31




---



##### Table of Contents



Parent
    Options
  Section Subsidiaries
        Section No
    Conflict
  Section 6.5(b)
  Section 7.8
  Section SEC
    Documents; Financial Statements
   A-32




---



##### Table of Contents



Parent Reports
  Form 10-Q
    Section Disclosure
    and Internal Controls and Procedures
        Rule 13a-15(e) 15d-15(e) Rule 13a-15
  Rule 13a-15(f) 15d-15(f)
 A-33




---



##### Table of Contents



Sarbanes-Oxley Form 10-K
    Section Compliance
    with Laws; Permits
    Parent Permits
  Section Litigation
      Section Absence
    of Certain Changes.
         A-34




---



##### Table of Contents



Section Taxes
     A-35




---



##### Table of Contents



Section 1.6011-4(b)(1) Section 1.6011-4 2002-2, 2002-2
            Section Employee
    Benefit Plans
  Section 6.12(a) U.S.-based
 A-36




---



##### Table of Contents



U.S.-based
  non-U.S. based non-U.S. based non-U.S. based
  non-U.S. jurisdictions non-U.S. based
    2005-1
     A-37




---



##### Table of Contents



non-U.S. law),
  non-U.S. law,
  non-U.S. based non-U.S. plan non-U.S. plan non-U.S. plan
  Section Labor
    and Employee Matters
  and/or
 A-38




---



##### Table of Contents



Section Environmental
    Matters
         A-39




---



##### Table of Contents



Section Properties
  Form 10-K
        Section 6.15(e)
  Section Intellectual
    Property
  Section 6.16(a) Parent
    Registered IP off-the-shelf-software)
     A-40




---



##### Table of Contents



Section Insurance. Section 6.17 Section 6.17
  Section Certain
    Contracts
  Section 6.18
          Regulation S-K
    Section 6.18(a)(vii)
  Parent
    Material Contract
 A-41




---



##### Table of Contents



Section Government
    Contract. Section 6.19 Section 6.19(a)
  Section No
    Brokers.
  Section Company
    Stock Ownership.
  Section Vote
    Required. Parent Shareholder
    Approval
  Section Improper
    Payments
   A-42




---



##### Table of Contents



Section Affiliate
    Transactions. Section 6.24 Parent Affiliate
    Transaction
  ARTICLE VII.
  COVENANTS
  Section Conduct
    of Business by the Company. Section 7.1
       A-43




---



##### Table of Contents



provided gross-up
           A-44




---



##### Table of Contents



Form 10-K
        Section 7.1(n)
          Section 7.3 Section 8.2(d)
   A-45




---



##### Table of Contents



Section Conduct
    of Business by Parent. Section 7.1
        provided gross-up
   A-46




---



##### Table of Contents



Form 10-K
        Section 7.2(n)
       A-47




---



##### Table of Contents



Section 7.3 Section 8.3(d)
    Section No
    Solicitation
  No-Shop Party Other Party Section 7.3 Section 7.3(a)
  No-Shop Section 7.3(a) Confidentiality
    Agreement
  Section 7.3(b)
 A-48




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##### Table of Contents



Company Adverse Recommendation
    Change Parent Adverse Recommendation
    Change
  Section 7.3 Superior Acquisition
    Proposal Termination Section 9.5(a) Section 9.5(b) provided however
  Change/Intent
    to Terminate Notice
      Section 7.3(b) Section 7.3(b)
  Section 7.3
 A-49




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##### Table of Contents



Section 7.3 Rule 14e-2(a) Rule 14d-9 provided, however Section 7.3(b
      Acquisition Proposal
  Special Valuation Proposal
  Superior Proposal break-up Section 7.3
 A-50




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##### Table of Contents



Section Preparation
    of Proxy Statement; Meetings of Shareholders
  Proxy Statement/Prospectus Form S-4 Form S-4 Form S-4 Form S-4 Form S-4 Form S-4 Form S-4 Form S-4,
  Form S-4, Form S-4 Form S-4.
  Form S-4
  Form S-4 Form S-4
   A-51




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##### Table of Contents



Company
    Shareholders Meeting Form S-4 Section 7.3(b) Section 7.3 Section 7.3
  Parent Shareholders Meeting Form S-4 Section 7.3(b) Section 7.3 Section 7.3
  Section Filings;
    Reasonable Best Efforts
  Section 7.3 provided
   A-52




---



##### Table of Contents



Section Inspection. Section 7.6 Section 7.6 Section 7.6
  Section Publicity. Section 7.4 Section 7.3
 A-53




---



##### Table of Contents



Section Listing
    Application.
  Section Section 16
    Matters. Rule 16b-3
  Section Expenses. Section 9.5 Section 7.5(a) Form S-4 Section 7.8
  Section Indemnification
    and Insurance
    six-years Section 7.11(b)
  Section 7.11 Section 7.11(c) Existing Indemnification
    Agreements Section 7.11
  Section 7.11
  Section Antitakeover
    Statutes.
  Section Notification.
 A-54




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##### Table of Contents



Section Employee
    Matters
  Continuing Employees Affected Participants
      Section 7.14(a) out-of-pocket
  Company
    Qualified Plans Post-Closing Plan
 A-55




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##### Table of Contents



Section 7.14
  Section Other
    Pre-Closing Matters
  Exhibit E Section 7.15(a)(ii) Exhibit E Section 7.15(a)(ii) Exhibit F
  Reconfirmation Opinion
  Section 7.15(c) Section 7.15(c)
  Section Shareholder
    Litigation. and/or and/or
  Section Tax
    Treatment.
  ARTICLE VIII.
  CONDITIONS
  Section Conditions
    to Each Partys Obligation to Effect the
    Merger.
       A-56




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##### Table of Contents



Form S-4 Form S-4
        Section Conditions
    to Obligation of the Company to Effect the
    Merger.
        Section 8.2(a) (b) (c)
   A-57




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##### Table of Contents



Section Conditions
    to Obligation of Parent and Merger Sub to Effect the
    Merger.
        Section 8.3(a) (b) (c)
  Section 8.3(e)
  Section 7.15(a)(ii) Section 7.15(a)(ii)
  Section Frustration
    of Conditions.
  ARTICLE IX.
  TERMINATION
  Section Termination
    by Mutual Consent.
  Section Termination
    by Parent or the Company.
  Termination Date provided, however, Section 8.1(b) Section 8.1(c) provided, further
 A-58




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##### Table of Contents



provided, however, Section 9.2(d) Section 7.5
  Section 4.1(b)
  Section Termination
    by the Company.
  Section 8.2(a) Section 8.2(b) provided, however Section 9.3(a) Section 8.3(a) Section 8.3(b)
    Section 7.3 Section 9.5(a)
  Section 8.2(e) provided however Section 8.1 provided, further Section 9.3(d) Section 8.3(a) Section 8.3(b)
  Section Termination
    by Parent.
  Section 8.3(a) Section 8.3(b) provided, however Section 9.4(a) Section 8.2(a) Section 8.2(b)
     A-59




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##### Table of Contents



Section 7.3 Section 9.5(b)
  Section 8.2(e) provided however Section 8.1 Section 8.2(e) provided, further Section 9.4(d) Section 8.2(a) Section 8.2(b)
  Section Effect
    of Termination
    Section 9.2(a) Section 9.2(b) Section 9.4(a) Section 9.2(b) provided, however, Section 9.2(b) Section 9.4(b) Section 9.5
  Section 9.3(d) Section 9.4(d)
  Section 9.4(b)
  Section 9.3(c)
  provided Section 9.5(a)
    Section 9.2(a) Section 9.2(c) Section 9.3(a) Section 9.2(c) provided,
    however, Section 9.2(c) Section 9.3(b) Section 9.5
  Section 9.3(b)
  Section 9.4(c)
  provided Section 9.5(b)
 A-60




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##### Table of Contents



Section 9.2(b) Section 9.2(b)
  Section 9.3(c Section 9.3(d)
  Section 9.4(a) Section 9.4(b) Section 9.4(d)
      Section 9.2(c) Section 9.2(c)
  Section 9.4(c)
  Section 9.3(a) Section 9.3(b)
    Section 9.5(c) Section 9.5(d) Section 9.5(a)(i) Section 9.5(b)(i) Section 9.5(c) Section 9.5(d)
  Section 9.5 Section 9.5 Section 9.5 Section 9.5 The Wall Street
    Journal. Section 9.5 same-day
  Section 9.5(a) Section 9.5(b) Related
    Persons
 A-61




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##### Table of Contents



Section 9.1 Section 9.4 Section 7.6 Section 7.10 provided Section 9.5(g)
  Section Extension;
    Waiver.
  ARTICLE X.
  GENERAL
    PROVISIONS
  Section Nonsurvival
    of Representations, Warranties and
    Agreements. Sections 3.1 Section 3.2 Section 7.10 Section 7.11 Section 7.14
 A-62




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##### Table of Contents



Section Notices.
    (972) 424-3943
    (817) 348-2384
    (432) 684-3030
    (214) 661-4954
    Section Assignment;
    Binding Effect; Benefit. Section 7.11
  Section Entire
    Agreement.
 A-63




---



##### Table of Contents



Section Amendments.
  Section Governing
    Law.
  Section Headings.
  Section Definitions
    and Interpretation.
    Affiliate
  Antitrust Laws Non-U.S. Antitrust
  Applicable Law non-U.S. law
  Company IP
  Company Material Adverse Effect
  Contract
  Debt
 A-64




---



##### Table of Contents



GAAP
  Governmental Authority
  Intellectual Property
  Material Adverse Effect
  Parent IP
  Parent Material Adverse Effect
  Permitted Liens
  Person
 A-65




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##### Table of Contents



Proceeding
  Representatives
  Subsidiary
  Tax Taxes Regulation Section 1.1502-6 non-U.S.).
  Section 10.3
  Section 10.8
      Section Severability.
  Section Enforcement
    of Agreement.
 A-66




---



##### Table of Contents



Section Consent
    to Jurisdiction and Venue; Appointment of Agent for Service of
    Process.
  Section No
    Recourse.
  Section Counterparts.
  [signature
    page follows]
 A-67




---



##### Table of Contents



By:
    /s/  Stephen
    C. Jumper   Title:
    President and Chief Executive Officer    By:
    /s/  Stephen
    C. Jumper   Title:
    President    By:
    /s/  Wayne
    A. Whitener   Title:
    President and Chief Executive Officer  [signature
    page to Agreement and Plan of Merger]
 A-68




---



##### Table of Contents



EXHIBIT A
     RESTATED
    CERTIFICATE OF FORMATION
    OF
    TGC INDUSTRIES, INC.,
    A TEXAS FOR-PROFIT CORPORATION
      A-A-1




---



##### Table of Contents



ARTICLE I
  NAME
    ARTICLE II
  ENTITY TYPE
    ARTICLE III
  PURPOSE
  Code
  ARTICLE IV
  AUTHORIZED
    SHARES
    ARTICLE V
  REGISTERED
    OFFICE
    ARTICLE VI
  DIRECTORS
    ARTICLE VII
  INDEMNIFICATION
   A-A-2




---



##### Table of Contents



A-A-3




---



##### Table of Contents



ARTICLE VIII
  EXCULPATION
               A-A-4




---



##### Table of Contents



EXHIBIT B
  SECOND AMENDED AND RESTATED BYLAWS
    OF
    TGC INDUSTRIES, INC.
    (Amended and Restated
    on          ,
    2011)
  A-B-1




---



##### Table of Contents



ARTICLE I
  OFFICES
  Section 1.1. Registered
    Office.
  Section 1.2 Other
    Offices.
  ARTICLE II
  MEETINGS
    OF SHAREHOLDERS
  Section 2.1 Place
    of Meetings.
  Section 2.2 Annual
    Meeting.
  Section 2.3 Special
    Meetings.
  Section 2.4 Notice
    of Meeting.
  Section 2.5 Quorum.
  Section 2.6 Voting.
 A-B-2




---



##### Table of Contents



Section 2.7 Proxies.
  Section 2.8 Shareholder
    Action Without a Meeting.
  Section 2.9 Telephone
    Meetings.
  ARTICLE III
  DIRECTORS
  Section 3.1 Number
    and Tenure.
  Section 3.2 Qualifications.
  Section 3.3 Vacancies.
      Section 3.4 Place
    of Meeting.
 A-B-3




---



##### Table of Contents



Section 3.5 Regular
    Meetings.
  Section 3.6 Special
    Meetings.
  Section 3.7 Attendance
    at and Notice of Meetings.
  Section 3.8 Quorum
    of and Action by Directors.
  Section 3.9 Compensation.
  Section 3.10 Removal.
  Section 3.11 Resignations.
  Section 3.12 Committees
    of the Board of Directors.
   A-B-4




---



##### Table of Contents



Section 3.13 Board
    and Committee Action Without a
    Meeting.
  Section 3.14 Telephone
    Meetings.
  ARTICLE IV
  OFFICERS
  Section 4.1 Officers.
      Section 4.2 Vacancies.
  Section 4.3 Removal.
  Section 4.4 Resignations.
  Section 4.5 President.
 A-B-5




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##### Table of Contents



Section 4.6 Vice
    President.
  Section 4.7 Secretary.
  Section 4.8 Delegation
    of Authority.
  ARTICLE V
  CAPITAL
    STOCK
  Section 5.1 Certificates
    of Shares.
 A-B-6




---



##### Table of Contents



Section 5.2 Share
    Transfer Records.
  ARTICLE VI
  INDEMNIFICATION
  Section 6.1
                 A-B-7




---



##### Table of Contents



A-B-8




---



##### Table of Contents



ARTICLE VII
  LIMITATION
    ON LIABILITY
  Section 7.1
              ARTICLE VIII
  MISCELLANEOUS
    PROVISIONS
  Section 8.1 Bylaw
    Amendments.
  Section 8.2 Books
    and Records.
  Section 8.3 Waiver.
  Section 8.4 Seal.
  Section 8.5 Fiscal
    Year.
 A-B-9




---



##### Table of Contents



Exhibit
    C
  Please see Annex E to this Joint Proxy
    Statement/Prospectus




---



##### Table of Contents



Exhibit
    D
  Please see Annex D to this Joint Proxy
    Statement/Prospectus




---



##### Table of Contents



Exhibit
    E
  Please see Annex F to this Joint Proxy
    Statement/Prospectus




---



##### Table of Contents



Exhibit
    F
  Please see Annex G to this Joint Proxy
    Statement/Prospectus




---



##### Table of Contents



ANNEX B  
                 Form 10-K
  and/or
               Raymond
    James & Associates, Inc. Member
    New York Stock Exchange/SIPC
    2001 Ross Avenue,  
    Suite 4550   Dallas, TX 75201214-720-1314 
    214-720-1315  Fax 
    800-393-1314 
    www.raymondjames.com
 B-1




---



##### Table of Contents



B-2




---



##### Table of Contents



B-3




---



##### Table of Contents



ANNEX
    C  
  March 20,
    2011
         1 3
      Southwest Securities,
    Inc.   1201 Elm Street,
    Suite 3500   Dallas, Texas
    75270-2180 
    214.859.1800  
    www.swst.comMEMBER: NEW YORK STOCK EXCHANGE
 C-1




---



##### Table of Contents



C-2




---



##### Table of Contents



By:
    /s/  Paul
    M. Moorman    C-3




---



##### Table of Contents



ANNEX
    D  FORM OF
    VOTING AGREEMENT
  Agreement Parent Voting Shareholder
  RECITALS
  Company Merger Sub Merger
    Agreement Merger Company Common Stock 1 3 Parent Common Stock
  Subject
    Shares
      Section 1. Certain
    Definitions.
  Agreement
  Beneficially Owned Beneficial Ownership Rule 13d-3
  Beneficial Owner
  Company
  Company Common Stock
  Expiration Date
  Merger
 D-1




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##### Table of Contents



Merger Agreement
  Merger Sub
  Parent Common Stock
  Parent
  Subject Shares
  Transfer Transfer
  Voting Shareholder
  Section 2. No
    Disposition or Solicitation
  power-of-attorney
    Section 3. Voting
    of Subject Shares.
  Section 4. Reasonable
    Efforts to Cooperate.
 D-2




---



##### Table of Contents



Section 5. Irrevocable
    Proxy.
  Section 6. Further
    Action.
  Section 7. Representations
    and Warranties of the Voting Shareholder.
         D-3




---



##### Table of Contents



Section 8. Termination.
  Section 9. Shareholder
    Capacity.
  Section 10. Miscellaneous
  Notices.
        (432) 684-3030
 D-4




---



##### Table of Contents



(214) 661-4954
            (817) 348-2384
    Assignment; Binding Effect;
    Benefit.
  Entire Agreement.
  Amendments.
  Extension; Waiver.
 D-5




---



##### Table of Contents



Governing Law.
  Headings.
  Severability.
  Enforcement of Agreement.
  Consent to Jurisdiction and Venue; WAIVER OF JURY
    TRIAL.
  Counterparts.
  No Presumption.
  [signature pages follow]
 D-6




---



##### Table of Contents



By:   Title:  [Voting
    Agreement  Parent Signature Page]
 D-7




---



##### Table of Contents



By:   Address:  [Voting
    Agreement  Voting Shareholder Signature
    Page]
 D-8




---



##### Table of Contents



Schedule A
  Name

Number of Shares  D-9




---



##### Table of Contents



ANNEX E  FORM OF
    VOTING AGREEMENT
  Agreement Company Voting Shareholder Voting Shareholders
  RECITALS
  Parent Merger Sub Merger
    Agreement Merger Company Common Stock 1 3 Parent Common Stock
  Subject
    Shares
      Section 1. Certain
    Definitions.
  Agreement
  Beneficially Owned Beneficial Ownership Rule 13d-3
  Beneficial Owner
  Company
  Company Common Stock
  Expiration Date
 E-1




---



##### Table of Contents



Merger
  Merger Agreement
  Merger Sub
  Parent Common Stock
  Parent
  Subject Shares
  Transfer Transfer
  Voting Shareholder
  Section 2. No
    Disposition or Solicitation
  power-of-attorney
    Section 3. Voting
    of Subject Shares.
  Section 4. Reasonable
    Efforts to Cooperate.
 E-2




---



##### Table of Contents



Section 5. Irrevocable
    Proxy.
  Section 6. Further
    Action.
  Section 7. Representations
    and Warranties of the Voting Shareholders.
         E-3




---



##### Table of Contents



Section 8. Termination.
  Section 9. Shareholder
    Capacity.
  Section 10. Miscellaneous
  Notices.
        (972) 424-3943
 E-4




---



##### Table of Contents



(817) 348-2384
            (214) 661-4954
    Assignment; Binding Effect;
    Benefit.
  Entire Agreement.
  Amendments.
  Extension; Waiver.
  Governing Law.
 E-5




---



##### Table of Contents



Headings.
  Severability.
  Enforcement of Agreement.
  Consent to Jurisdiction and Venue; WAIVER OF JURY
    TRIAL.
  Counterparts.
  No Presumption.
  Obligations.
  [signature
    pages follow]
 E-6




---



##### Table of Contents



By:   Title:  [Voting
    Agreement  Company Signature Page]
  [Voting
    Shareholder Signature Page Begins on Next Page]
 E-7




---



##### Table of Contents



By:   Address:  [Voting
    Agreement  Voting Shareholder Signature
    Page]
 E-8




---



##### Table of Contents



Schedule A
  Name

Number of Shares  E-9




---



##### Table of Contents



ANNEX F  EMPLOYMENT
    AGREEMENT
  Agreement Effective Date 1 Company Executive Parties
  RECITALS
      AGREEMENT
    Definitions
    Affiliate
    Board
    Cause nolo
    contendere
  Competition Entities
    1
 F-1




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##### Table of Contents



Confidential Information
    Disability 12-month
    Good Reason 2
  Non-Competition Period
              2
 F-2




---



##### Table of Contents



Work Product
  Employment
    Duties. and/or not-for-profit
  Service on the Board. 3
  The Executives Ability to
    Perform.
  Term
  Initial Term.
    3
 F-3




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##### Table of Contents



Renewal Terms.
  Term.
  Compensation
    Base Salary.
    Bonus.
  Benefits
  Reimbursed
    Expenses.
  Benefits.
  Vacation, Holidays and Paid Time
    Off.
  Automobile.
  Key Man Insurance
   F-4




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##### Table of Contents



Termination of Employment
  Termination of Employment.
  Termination by the Company for
    Cause.
  Termination by the Company Without
    Cause. §1.409A-1(h).
  Termination by the Executive Without Good
    Reason. §1.409A-1(h).
  Termination by the Executive for Good
    Reason. 30-day §1.409A-1(h).
  Termination upon Death.
  Termination upon Disability. §1.409A-1(h).
  Effect of Termination.
  Payment Upon Termination for any
    Reason.
  Payment Upon Termination by the Company Without
    Cause or by the Executive for Good Reason.
 F-5




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##### Table of Contents



Return of Company
    Property.
  Defense of Claims.
  Form of Payments.
  Automobile Upon
    Termination.
 F-6




---



##### Table of Contents



Confidentiality
  Provision of Confidential Information;
    Acknowledgements. ,
  Non-Disclosure of the Confidential
    Information. This contractual confidentiality
    obligation shall be in addition to, and in no way a limitation
    of, all such confidentiality obligations as may exist at law or
    in equity.
  Restrictive Covenants
  Consideration; Voluntary
    Agreement.
  Non-Competition.
  Non-Solicitation of
    Customers.
 F-7




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##### Table of Contents



Non-Solicitation of
    Employees.
  Non-Disparagement.
  Reasonableness of Scope.
  Discoveries and Inventions
  Assignment of Work Product to the
    Company.
  Cooperation; Grant of
    License.
 F-8




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##### Table of Contents



Injunctive Relief
    Arbitration
    provided
         F-9




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Miscellaneous
  Notification of Restrictions to Third
    Parties.
  Severability.
  Entire Agreement.
  Withholding and other
    Deductions.
  Headings; Interpretation.
  Notices.
 F-10




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Modification; Waiver.
  Successors and Assigns.
  Applicable Law; Venue.
  Section 409A.
      Survival of Obligations.
  Knowledge and Legal
    Representation. THE EXECUTIVE ACKNOWLEDGES
    THAT THE EXECUTIVE HAS CAREFULLY READ THIS AGREEMENT, HAS
    CONSULTED WITH AN ATTORNEY OF THE EXECUTIVES CHOOSING TO
    THE EXTENT THE EXECUTIVE DESIRES LEGAL ADVICE REGARDING THIS
    AGREEMENT, AND UNDERSTANDS AND AGREES TO ALL OF THE PROVISIONS
    IN THIS AGREEMENT.
  Counterparts.
   [signature page follows]
 F-11




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THE EXECUTIVE:
     COMPANY:
    By:   Title: F-12




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ANNEX G  FORM OF
    INDEMNIFICATION AGREEMENT
  Agreement Company Indemnitee
    and/or and/or
    TBOC and/or
    and/or
    and/or
  Certain Definitions.
  Agreement
  Board
  Change in Control Rule 13d-3
 G-1




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Company
  Disqualifying Event
  Exchange Act
  Expenses
  Indemnifiable Event and/or
  Indemnitee
  Special Legal Counsel
  Proceeding
  TBOC
  Indemnification Arrangement.
 G-2




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Advancement or Reimbursement of
    Expenses.
  No Settlement without
    Consent.
  Request for Indemnification.
  Determination of Request.
    and/or
 G-3




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Disqualifying Event
  Effect of Certain
    Proceedings. nolo contendere
  Expenses of Enforcement of
    Agreement.
 G-4




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##### Table of Contents



Common
    Attorney. conflicts-of-interest
  Nonexclusive Rights; Subsequent Change in
    Law.
  D&O Liability
    Insurance. and/or and/or
  No Employment Rights. and/or
  Amendments; Waiver.
 G-5




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##### Table of Contents



Subrogation.
  Term. and/or
  Notification and Defense of
    Claims.
  Binding Effect. and/or and/or
  Severability.
  Governing Law.
  Notice.
         Signature page follows
 G-6




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By:  Title:     Address: G-7




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PART II. INFORMATION
    NOT REQUIRED IN PROSPECTUS
  ITEM 20.
    INDEMNIFICATION
    OF DIRECTORS AND OFFICERS  Texas Law
    and Dawsons Governing Documents
               II-1




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##### Table of Contents




    a breach of the directors duty of loyalty to the
    corporation or its shareholders;
    an act or omission not in good faith that constitutes a breach
    of duty of the director to the corporation or which involves
    intentional misconduct or a knowing violation of law;
    a transaction from which the director received an improper
    personal benefit, regardless of whether the benefit resulted
    from an action taken within the scope of the directors
    duties; or
    an act or omission for which the liability of a director is
    expressly provided by an applicable statute.        Indemnification
    Agreements
     II-2




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##### Table of Contents



Insurance
    ITEM 21.
    EXHIBITS AND
    FINANCIAL STATEMENT SCHEDULES  
 ExhibitNumber

Description2
.1#

Agreement and Plan of Merger, dated March 18, 2011, by and
    among Dawson Geophysical Company, 6446 Acquisition Corp. and TGC
    Industries, Inc. (attached as Annex A to the joint proxy
    statement/prospectus that is part of this Registration
    Statement).2
.2

Form of Voting Agreement by and between Dawson Geophysical
    Company and the shareholders of TGC Industries, Inc. signatories
    thereto (attached as Annex D to the joint proxy
    statement/prospectus that is part of this Registration
    Statement).3
.1

Second Restated Articles of Incorporation of Dawson Geophysical
    Company, as amended (filed on February 9, 2007 as
    Exhibit 3.1 to Dawson Geophysical Companys Quarterly
    Report on
    Form 10-Q
    for the quarter ended December 31, 2006 (File
    No. 000-10144)
    and incorporated herein by reference and filed on
    November 28, 2007 as Exhibit 3.1 to Dawson Geophysical
    Companys Current Report on
    Form 8-K
    (File
    No. 000-10144)
    and incorporated herein by reference).3
.2

Second Amended and Restated Bylaws of Dawson Geophysical
    Company, as amended (filed on November 23, 2010 as
    Exhibit 3.2 to Dawson Geophysical Companys Annual
    Report on
    Form 10-K
    for the fiscal year ended September 30, 2010 (File
    No. 001-34404)
    and incorporated herein by reference).3
.3

Amendment No. 2 to Second Amended and Restated Bylaws, as
    amended, of Dawson Geophysical Company (filed on March 21,
    2011 as Exhibit 3.1 to Dawson Geophysical Companys
    Current Report on
    Form 8-K
    (File
    No. 001-34404)
    and incorporated herein by reference).3
.4

Statement of Resolution Establishing Series of Shares of
    Series A Junior Participating Preferred Stock of Dawson
    Geophysical Company (filed on July 9, 2009 as
    Exhibit 3.1 to Dawson Geophysical Companys Current
    Report on
    Form 8-K
    (File
    No. 000-10144)
    and incorporated herein by reference).4
.1

Rights Agreement effective as of July 23, 2009 between
    Dawson Geophysical Company and Mellon Investor Services LLC, as
    Rights Agent, which includes as Exhibit A the form of
    Statement of Resolution Establishing Series of Shares of
    Series A Junior Participating Preferred Stock setting forth
    the terms of the Preferred Stock, as Exhibit B the form of
    Rights Certificate and as Exhibit C the Summary of Rights
    to Purchase Preferred Stock (filed on July 9, 2009 as
    Exhibit 4.1 to Dawson Geophysical Companys Current
    Report on
    Form 8-K
    (File
    No. 000-10144)
    and incorporated herein by reference).5
.1*

Opinion of Baker Botts L.L.P.8
.1*

Opinion of Baker Botts L.L.P. regarding tax matters.8
.2*

Opinion of Haynes and Boone, LLP regarding tax matters.10
.1

Form of Employment Agreement (attached as Annex F to the
    joint proxy statement/prospectus that is part of this
    Registration Statement).10
.2

Form of Indemnification Agreement (attached as Annex G to
    the joint proxy statement/prospectus that is part of this
    Registration Statement).23
.1*

Consent of Baker Botts L.L.P. (included in the Opinion filed as
    Exhibit 5.1).23
.2*

Consent of Baker Botts L.L.P. (included in the Opinion filed as
    Exhibit 8.1).23
.3*

Consent of Haynes and Boone, LLP (included in the Opinion filed
    as Exhibit 8.2). 
 II-3




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##### Table of Contents



ExhibitNumber

Description23
.4*

Consent of KPMG LLP, independent registered public accounting
    firm for Dawson Geophysical Company.23
.5*

Consent of Lane Gorman Trubitt, P.L.L.C., independent registered
    public accounting firm for TGC Industries, Inc.24
.1

Powers of Attorney.99
.1

Form of Proxy Card for Dawson Geophysical Companys Special
    Meeting.99
.2

Form of Proxy Card for TGC Industries, Inc.s Special
    Meeting.99
.3*

Consent of Raymond James & Associates, Inc.99
.4*

Consent of Southwest Securities, Inc.99
.5

Form of Voting Agreement by and between TGC Industries, Inc. and
    the shareholders of Dawson Geophysical Company signatories
    thereto (attached as Annex E to the joint proxy
    statement/prospectus that is part of this Registration
    Statement).99
.6*

Consent of Wayne A. Whitener99
.7*

Consent of Allen T. McInnes  
    *
    
    Filed herewith. 
  
    
    Previously filed. 
 
  #
    
    The registrant hereby agrees to supplementally furnish the
    Securities and Exchange Commission, on a confidential basis, a
    copy of any omitted schedule upon the staffs request. 
  ITEM 22.
    UNDERTAKINGS  Regulation S-K,
    Item 512(a) Undertaking:
               II-4




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##### Table of Contents



Regulation S-K,
    Item 512(b) Undertaking:
    Regulation S-K,
    Item 512(g) Undertaking:
     II-5




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##### Table of Contents



Regulation S-K,
    Item 512(h) Undertaking:
    Form S-4,
    Item 22(b) Undertaking:
    Form S-4,
    Item 22(c) Undertaking:
   II-6




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##### Table of Contents



SIGNATURES
 
   
  DAWSON GEOPHYSICAL COMPANY
  By:
    /s/  Stephen
    C. Jumper    
   
  Signature

Title*L.
    Decker Dawson

Chairman of the Board/s/  Stephen
    C. JumperStephen
    C. Jumper

President,
    Chief Executive Officer and Director
    (Principal Executive Officer)*Paul
    H. Brown

Director*Craig
    W. Cooper

Director*Gary
    M. Hoover

Director*Jack
    D. Ladd

Director*Ted
    R. North

Director*Tim
    C. Thompson

Director*Christina
    W. Hagan

Executive Vice President, Secretary and 
    Chief Financial Officer
    (Principal Financial and Accounting Officer)    
  *
    
    The undersigned, by signing his name hereto, signs and executes
    this Amendment No. 1 to the Registration Statement pursuant
    to the Powers of Attorney executed by the above-named
    signatories and previously filed with the Securities and
    Exchange Commission. 
  
 /s/  Stephen
    C. JumperStephen
    C. JumperAttorney-in-fact  
 II-7




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##### Table of Contents



EXHIBIT INDEX
  
 ExhibitNumber

Description2
.1#

Agreement and Plan of Merger, dated March 18, 2011, by and
    among Dawson Geophysical Company, 6446 Acquisition Corp. and TGC
    Industries, Inc. (attached as Annex A to the joint proxy
    statement/prospectus that is part of this Registration
    Statement).2
.2

Form of Voting Agreement by and between Dawson Geophysical
    Company and the shareholders of TGC Industries, Inc. signatories
    thereto (attached as Annex D to the joint proxy
    statement/prospectus that is part of this Registration
    Statement).3
.1

Second Restated Articles of Incorporation of Dawson Geophysical
    Company, as amended (filed on February 9, 2007 as
    Exhibit 3.1 to Dawson Geophysical Companys Quarterly
    Report on
    Form 10-Q
    for the quarter ended December 31, 2006 (File
    No. 000-10144)
    and incorporated herein by reference and filed on
    November 28, 2007 as Exhibit 3.1 to Dawson Geophysical
    Companys Current Report on
    Form 8-K
    (File
    No. 000-10144)
    and incorporated herein by reference).3
.2

Second Amended and Restated Bylaws of Dawson Geophysical
    Company, as amended (filed on November 23, 2010 as
    Exhibit 3.2 to Dawson Geophysical Companys Annual
    Report on
    Form 10-K
    for the fiscal year ended September 30, 2010 (File
    No. 001-34404)
    and incorporated herein by reference).3
.3

Amendment No. 2 to Second Amended and Restated Bylaws, as
    amended, of Dawson Geophysical Company (filed on March 21,
    2011 as Exhibit 3.1 to Dawson Geophysical Companys
    Current Report on
    Form 8-K
    (File
    No. 001-34404)
    and incorporated herein by reference).3
.4

Statement of Resolution Establishing Series of Shares of
    Series A Junior Participating Preferred Stock of Dawson
    Geophysical Company (filed on July 9, 2009 as
    Exhibit 3.1 to Dawson Geophysical Companys Current
    Report on
    Form 8-K
    (File
    No. 000-10144)
    and incorporated herein by reference).4
.1

Rights Agreement effective as of July 23, 2009 between
    Dawson Geophysical Company and Mellon Investor Services LLC, as
    Rights Agent, which includes as Exhibit A the form of
    Statement of Resolution Establishing Series of Shares of
    Series A Junior Participating Preferred Stock setting forth
    the terms of the Preferred Stock, as Exhibit B the form of
    Rights Certificate and as Exhibit C the Summary of Rights
    to Purchase Preferred Stock (filed on July 9, 2009 as
    Exhibit 4.1 to Dawson Geophysical Companys Current
    Report on
    Form 8-K
    (File
    No. 000-10144)
    and incorporated herein by reference).5
.1*

Opinion of Baker Botts L.L.P.8
.1*

Opinion of Baker Botts L.L.P. regarding tax matters.8
.2*

Opinion of Haynes and Boone, LLP regarding tax matters.10
.1

Form of Employment Agreement (attached as Annex F to the
    joint proxy statement/prospectus that is part of this
    Registration Statement).10
.2

Form of Indemnification Agreement (attached as Annex G to
    the joint proxy statement/prospectus that is part of this
    Registration Statement).23
.1*

Consent of Baker Botts L.L.P. (included in the Opinion filed as
    Exhibit 5.1).23
.2*

Consent of Baker Botts L.L.P. (included in the Opinion filed as
    Exhibit 8.1).23
.3*

Consent of Haynes and Boone, LLP (included in the Opinion filed
    as Exhibit 8.2).23
.4*

Consent of KPMG LLP, independent registered public accounting
    firm for Dawson Geophysical Company.23
.5*

Consent of Lane Gorman Trubitt, P.L.L.C., independent registered
    public accounting firm for TGC Industries, Inc.24
.1

Powers of Attorney.99
.1

Form of Proxy Card for Dawson Geophysical Companys Special
    Meeting.99
.2

Form of Proxy Card for TGC Industries, Inc.s Special
    Meeting.




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##### Table of Contents



ExhibitNumber

Description99
.3*

Consent of Raymond James & Associates, Inc.99
.4*

Consent of Southwest Securities, Inc.99
.5

Form of Voting Agreement by and between TGC Industries, Inc. and
    the shareholders of Dawson Geophysical Company signatories
    thereto (attached as Annex E to the joint proxy
    statement/prospectus that is part of this Registration
    Statement).99
.6*

Consent of Wayne A. Whitener99
.7*

Consent of Allen T. McInnes  
    *
    
    Filed herewith. 
  
    
    Previously filed. 
 
  #
    
    The registrant hereby agrees to supplementally furnish the
    Securities and Exchange Commission, on a confidential basis, a
    copy of any omitted schedule upon the staffs request.