UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C.  20549

                                  SCHEDULE 13G

                                 (Rule 13d-102)

INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT
TO RULES 13D-1 (b)(c), AND (d) AND AMENDMENTS THERETO FILED
PURSUANT TO RULE 13d-2(b)

                   Under the Securities Exchange Act of 1934
                             (Amendment No.  )*


                            ORION MARINE GROUP, INC.
-------------------------------------------------------------------------
                                (Name of Issuer)

                                  COMMON STOCK
--------------------------------------------------------------------------
                         (Title of Class of Securities)

                                   68628V308
                        ------------------------------
                                 (CUSIP Number)

                               December 31, 2009
----------------------------------------------------------------------------
            (Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this
Schedule is filed:

     [X] Rule 13d-1(b)
     [_] Rule 13d-1(c)
     [_] Rule 13d-1(d)

*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the Notes)













                                  SCHEDULE 13G
=======================================================================
  CUSIP NO. 68628V308         ---------
- ---------------------------------------------------------------------
      NAMES OF REPORTING PERSONS.
 1    I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY).

      THOMPSON, SIEGEL & WALMSLEY LLC  54-0854396
- ---------------------------------------------------------------------
      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE
      INSTRUCTIONS)
 2                                                              (a) [_]
                                                                (b) [_]
- -------------------------------------------------------------------
      SEC USE ONLY
 3
- ---------------------------------------------------------------------
      CITIZENSHIP OR PLACE OF ORGANIZATION
 4
      DELAWARE
- --------------------------------------------------------------------
                          SOLE VOTING POWER
                     5
     NUMBER OF            1,488,015
      SHARES       ----------------------------------------------------
                          SHARED VOTING POWER
   BENEFICIALLY      6
     OWNED BY             285,375
                   ----------------------------------------------------
       EACH               SOLE DISPOSITIVE POWER
                     7
    REPORTING             1,773,390
      PERSON       ----------------------------------------------------
                          SHARED DISPOSITIVE POWER
       WITH          8
- ---------------------------------------------------------------------
      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
 9
      1,773,390
- ---------------------------------------------------------------------
      CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
      SHARES
10    (SEE INSTRUCTIONS)
                                                                    [_]
- ---------------------------------------------------------------------
      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
11
      6.62%
- ---------------------------------------------------------------------
      TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
12
      IA
- ---------------------------------------------------------------------







                                  SCHEDULE 13G
==========================================================================

Item 1

(a)  Name of Issuer
     ORION MARINE GROUP, INC.

(b) Address of Issuer's Principal Executive Offices
      12550 FUQUA STREET
      HOUSTON, TX  77034





Item 2

(a) Name of Person Filing
      THOMPSON, SIEGEL & WALMSLEY LLC

(b) Address of Principal Business Office or, if none, Residence
      6806 PARAGON PLACE, SUITE 300, RICHMOND, VA  23230

(b) Citizenship
      USA

(c) Title of Class of Securities
      COMMON STOCK

(d) CUSIP Number
      68628V308


Item 3. If this statement is filed pursuant to (S)(S)240.13d-1(b) or
        240.13d-2(b) or (c), check whether the person filing is a:

     (a) [_]  Broker or dealer registered under section 15 of the Act
              (15 U.S.C. 78o).

     (b) [_]  Bank as defined in section 3(a)(6) of the Act (15 U.S.C.78c).

     (c) [_]  Insurance company as defined in section 3(a)(19) of the Act
	      (15 U.S.C.78c).

     (d) [_]  Investment company registered under section 8 of the
              Investment Company Act of 1940 (15 U.S.C. 80a-8).

     (e) [X]  An investment adviser in accordance with
              (S)240.13d-1(b)(1)(ii)(E);

     (f) [_]  An employee benefit plan or endowment fund in accordance
              with (S)240.13d-1(b)(1)(ii)(F);

     (g) [_]  A parent holding company or control person in accordance
              with (S)240.13d-1(b)(1)(ii)(G);

     (h) [_]  A savings associations as defined in Section 3(b) of the
              Federal Deposit Insurance Act (12 U.S.C. 1813);

     (i) [_]  A church plan that is excluded from the definition of an
	      investment company under section 3(c)(14) of the Investment
              Company Act of 1940 (15 U.S.C. 80a-3);

     (j) [_]  Group, in accordance with (S)240.13d-1(b)(1)(ii)(J).


Item 4. Ownership.

     Provide the following information regarding the aggregate number
     and percentage of the class of securities of the issuer identified
     in Item 1.

(a) Amount beneficially owned:

     (b)  Percent of class:  6.62%

     (c)  Number of shares as to which the person has:

          (i)   Sole power to vote or to direct the vote 1,488,015

          (ii)  Shared power to vote or to direct the vote 285,375

          (iii) Sole power to dispose or to direct the disposition of 1,773,390

          (iv)  Shared power to dispose or to direct the disposition of

     Instruction. For computations regarding securities which represent a
     right to acquire an underlying security see (S)240.13d-3(d)(1).

Item 5.  Ownership of Five Percent or Less of a Class.

     If this statement is being filed to report the fact that as of the
     date hereof the reporting person has ceased to be the beneficial
     owner of more than five percent of the class of securities,
     check the following: [_]  Instruction: Dissolution of a group
     requires a response to this item.
     N/A

Item 6.  Ownership of More than Five Percent on Behalf of Another Person.

     If any other person is known to have the right to receive or the power
to direct the receipt of dividends from, or the proceeds from the sale of,
such securities, a statement to that effect should be included in response
to this item, and if such interest relates to more than five percent of
the class, such person should be identified. A listing of the shareholders
of an investment company registered under the Investment Company Act of
1940 or the beneficiaries of the employee benefit plan, pension fund or
endowment fund is not required.
	N/A

Item 7.  Identification and Classification of the Subsidiary Which
Acquired the Security Being Reported on by the Parent Holding Company.

     If a parent holding company has filed this schedule, pursuant to
Rule 13d-1(b)ii)(G), so indicate under Item 3(g) and attach an exhibit
stating the identity and the Item 3 classification of the relevant
subsidiary.  If a parent holding company has filed this schedule
pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit
stating the identification of the relevant subsidiary.
	N/A

Item 8.  Identification and Classification of Members of the Group.

     If a group has filed this schedule pursuant to
(S)240.13d-1(b)(1)(ii)(J), so indicate under Item 3(j) and attach
an exhibit stating the identity and Item 3 classification of each member
of the group. If a group has filed this schedule pursuant to
(S)240.13d-1(c) or (S)240.13d-1(d), attach an exhibit stating
the identity of each member of the group.
	N/A

Item 9.  Notice of Dissolution of a Group

     Notice of dissolution of a group may be furnished as an exhibit
stating the date of the dissolution and that all further filings with
respect to transactions in the security reported on will be filed,
if required, by members of the group, in their individual capacity.
See Item 5.

Item 10. Certification

(a) The following certification shall be included if the statement
is filed pursuant to (S)240.13d-1(b):

By signing below I certify that, to the best of my knowledge and
belief, the securities referred to above were acquired and are held
in the ordinary course of business and were not acquired and are
not held for the purpose of or with the effect of changing or
influencing the control of the issuer of the securities and were
not acquired and are not held in connection with or as a participant
in any transaction having that purpose or effect.

(b) The following certification shall be included if the statement
is filed pursuant to (S)240.13d-1(c):

By signing below I certify that, to the best of my knowledge and
belief, the securities referred to above were not acquired and
are not held for the purpose of or with the effect of changing or
influencing the control of the issuer of the securities and
were not acquired and are not held in connection with or as
a participant in any transaction having that purpose or effect.

                                   SIGNATURE

     After reasonable inquiry and to the best of my knowledge and
belief, I certify that the information set forth in this statement
is true, complete and correct.

                            February 10, 2010
                     -------------------------------
                                  Date

                        /s/ A. Gordon Goodykoontz
                     ------------------------------
                                 Signature

                          A. Gordon Goodykoontz/
                          Chief Compliance Officer
                       ------------------------------
                                Name/Title

     The original statement shall be signed by each person on
whose behalf the statement is filed or his authorized representative.
If the statement is signed on behalf of a person by his authorized
representative other than an executive officer or general partner
of the filing person, evidence of the representative's authority to
sign on behalf of such person shall be filed with the statement,
provided, however, that a power of attorney for this purpose
which is already on file with the Commission may be incorporated
by reference.  The name and any title of each person who signs
the statement shall be typed or printed beneath his signature.

NOTE: Schedules filed in paper format shall include a signed original
and five copies of the schedule, including all exhibits.
See (S)240.13d-7 for other parties for whom copies are to be sent.

     Attention: Intentional misstatements or omissions of fact
constitute Federal criminal violations (See 18 U.S.C. 1001)