DAWSON GEOPHYSICAL CO — Director's Dealing 2006

May 3, 2006

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: TGC INDUSTRIES INC (TGCI)
CIK: 0000799165
Period of Report: 2006-04-26

Reporting Person: BARRETT WILLIAM J (Director, 10% Owner)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2006-04-26	Common Stock	G	2000	—	Disposed	1505459	Direct
2006-04-28	Common Stock	G	1500	—	Disposed	1503959	Direct
2006-05-02	Common Stock	S	7000	$14.98	Disposed	1496959	Direct
2006-05-02	Common Stock	S	3893	$15.05	Disposed	1493066	Direct
2006-05-02	Common Stock	S	2700	$15.00	Disposed	132467	Indirect

Holdings (Derivative)

Security	Exercise Price	Expiration	Underlying	Shares	Ownership
Warrants (Series C2)	$.95	2007-12-15	Common Stock (5460)	5460	Indirect
Stock Option (reload)	$6.81	2010-10-10	Common Stock (1465)	1465	Direct

Footnotes

F1: The Reporting Person disclaims beneficial ownership of shares and warrants owned by spouse.

F2: Not applicable.

F3: Gift to charitable organization.