<PAGE>
<TABLE>
<CAPTION>
- -------- U.S. SECURITIES AND EXCHANGE COMMISSION ----------------------------
FORM 4 WASHINGTON, D.C. 20549 OMB APPROVAL
- -------- ----------------------------
/ / CHECK THIS BOX IF NO STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Omb Number: 3235-0287
LONGER SUBJECT TO Expires: September 30, 1998
SECTION 16. FORM 4 OR Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Estimated average burden
FORM 5 OBLIGATIONS MAY Section 17(a) of the Public Utility Holding Company Act of 1935 or hours per response .... 1.0
CONTINUE. SEE Section 30(f) of the Investment Company Act of 1940 ----------------------------
INSTRUCTION 1(b).
- -----------------------------------------------------------------------------------------------------------------------------------
<S> <C> <C>
1. Name and Address of Reporting Person* 2. Issuer Name and Ticker or Trading Symbol 6. Relationship of Reporting Person
to Issuer (Check all applicable)
Compagnie Generale de Geophysique GeoScience Corporation: GSCI Director X 10% Owner
---- ----
- --------------------------------------------------------------------------------------------- Officer (give Other
(Last) (First) (Middle) 3. IRS or Social Security 4. Statement for ---- title ---- (specify
Number of Reporting Month/Year below) below)
Person (Voluntary) ----------------- ------------------
1, rue Leon Migaux December, 1999
- -------------------------------------------- --------------------- 7. Individual or Joint/Group Filing
(Street) 5. If Amendment, (check applicable box)
Date of Original _X_Form filed by One Reporting Person
(Month/Year) ___Form filed by More than One
91341 Massy France Reporting Person
- ------------------------------------------------------------------------------------------------------------------------------------
(zip) (State) (Country) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
- ------------------------------------------------------------------------------------------------------------------------------------
1. Title of Security 2. Trans- 3. Trans- 4. Securities Acquired (A) 5. Amount of 6. Owner- 7. Nature
(Instr. 4) action action or Disposed of (D) Securities ship of In-
Date Code (Instr. 3, 4 and 5) Beneficially Form: direct
(Instr. 8) Owned at Direct Bene-
(Month/ End of (D) or ficial
Day/ ------------------------------------------- Month Indirect Owner-
Year) (A) or (Instr. 3 (I) ship
Code V Amount (D) Price and 4) (Instr. 4) (Instr. 4)
- ------------------------------------------------------------------------------------------------------------------------------------
Common Stock 12/13/99 P 9,414,263 A $6.71 D
- ------------------------------------------------------------------------------------------------------------------------------------
Common Stock 12/13/99 J 7,995,000 D* 0 I
- ------------------------------------------------------------------------------------------------------------------------------------
Common Stock 12/13/99 J ** ** ** D
- ------------------------------------------------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------------------------------------------------
* If the Form is filed by more than one Reporting Person, see Instruction 4(b)(v). (Over)
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1474 (7/96)
</TABLE>
Page 1 of 3 pages
<PAGE>
<TABLE>
<CAPTION>
FORM 4 (CONTINUED) TABLE II - DERIVATIVE SECURITIES ACQUIRED, DISPOSED OF, OR BENEFICIALLY OWNED
(E.G., PUTS, CALLS, WARRANTS, OPTIONS, CONVERTIBLE SECURITIES)
- ------------------------------------------------------------------------------------------------------------------------
1. Title of Derivative Security 2. Conver- 3. Trans- 4. Transac- 5. Number of Deriv- 6. Date Exer-
(Instr. 3) sion or action tion Code ative Securities Ac- cisable and Ex-
Exercise Date (Instr. 8) quired (A) or Dis- piration Date
Price of (Month/ posed of (D) (Month/Day/
Deriv- Day/ (Instr. 3, 4, and 5) Year)
ative Year)
Security
-------------------------------------- --------------------
Code V (A) (D) Date Expira-
Exer- tion
cisable Date
<S><C>------------------------------------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------------------------------------
<CAPTION>
- ------------------------------------------------------------------------------------------
7. Title and Amount of Under- 8. Price 9. Number 10. Owner- 11. Nature
lying Securities of of Deriv- ship of In-
(Instr. 3 and 4) Deriv- ative Form direct
ative Securi- of De- Bene-
Secur- ties rivative ficial
ity Bene- Secu- Own-
(Instr. ficially rity: ership
5) Owned Direct (Instr. 4)
- ------------------------------ at End (D) or
Amount or of Indi-
Title Number of Month rect (I)
Shares (Instr. 4) (Instr. 4)
<S><C>
- ------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------------
EXPLANATION OF RESPONSES:
COMPAGNIE GENERALE DE GEOPHYSIQUE
/s/ Thierry Le Roux 12/13/99
----------------------------------- -----------
**INTENTIONAL MISSTATEMENTS OR OMISSIONS OF FACTS CONSTITUTE **SIGNATURE OF REPORTING PERSON DATE
FEDERAL CRIMINAL VIOLATIONS. SEE 18 U.S.C. 1001 AND 15 U.S.C. 78ff(a).
NOTE: FILE THREE COPIES OF THIS FORM, ONE OF WHICH MUST BE MANUALLY SIGNED.
IF SPACE PROVIDED IS INSUFFICIENT, SEE INSTRUCTION 6 FOR PROCEDURE.
SEC 1474 (7/96) Page 2
</TABLE>
Page 2 of 3 pages
<PAGE>
1. Name and Address of Reporting Person
Compagnie Generale de Geophysique
1, rue Leon Migaux
91341 Massy, France
2. Issuer Name and Ticker or Trading Symbol
GeoScience Corporation: GSCI
4. Statement for Month / Year
December, 1999
* Compagnie Generale de Geophysique had the right to acquire these shares
pursuant to a shareholder agreement (the "Agreement") with Sercel Acquisition
Corp. (now known as Syntron Corporation), GeoScience Corporation and Tech-Sym
Corporation. When Syntron Corporation purchased these shares, the option expired
in accordance with the terms of the Agreement.
** Syntron Corporation, a wholly owned subsidiary of Compagnie Generale de
Geophysique and the owner of 94.3% of the outstanding stock of GeoScience
Corporation, merged itself with GeoScience Corporation, with Syntron Corporation
continuing as the surviving corporation. Pursuant to the merger, each of the 100
shares of common stock, par value $.01 per share, of Syntron Corporation issued
and outstanding immediately before the effective time of the merger now
represents one validly issued, fully paid nonassessable share of common stock,
par value $.01 per share, of the surviving corporation. Following the merger,
the common stock of GeoScience Corporation was deregistered by filing a Form 15.
Page 3 of 3 pages
