DAWSON GEOPHYSICAL CO — Director's Dealing 2005

May 9, 2005

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: TGC INDUSTRIES INC (TGCI)
CIK: 0000799165
Period of Report: 2005-05-05

Reporting Person: WHITENER WAYNE A (Director, President and CEO)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2005-05-05	Common Stock	M	2700	$1.00	Acquired	8514	Direct
2005-05-05	Common Stock	S	700	$3.75	Disposed	7814	Direct
2005-05-05	Common Stock	S	2000	$3.81	Disposed	5814	Direct
2005-05-06	Common Stock	M	2200	$1.00	Acquired	8014	Direct
2005-05-06	Common Stock	S	2200	$3.70	Disposed	5814	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2005-05-05	Stock Option	$1.00	M	2700	Disposed	2005-12-10	Common Stock (31800)	Direct
2005-05-06	Stock Option	$1.00	M	2200	Disposed	2005-12-10	Common Stock (29600)	Direct

Holdings (Derivative)

Security	Exercise Price	Expiration	Underlying	Shares	Ownership
Stock Option	$.80	2009-02-19	Common Stock (50000)	50000	Direct
Warrant	$.3	2009-07-31	Common Stock (50000)	50000	Direct

Footnotes

F1: Stock options are exercisable as follows: one-third exercisable after twelve months from date of grant; two-thirds exercisable after twenty-four months from date of grant; and all exercisable after thirty-six months from date of grant.

F2: See exercise price in column 2.

F3: Warrants issued as a bonus.