DAWSON GEOPHYSICAL CO — Director's Dealing 2004

Dec 15, 2004

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: TGC INDUSTRIES INC (TGCI)
CIK: 0000799165
Period of Report: 2004-12-13

Reporting Person: GARDNER HERBERT M (Director, 10% Owner)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2004-12-13	Common Stock	G	11000	—	Disposed	365272	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2004-12-15	Warrants (Series C2)	$1	P	1733	Acquired	2007-12-15	Common Stock (1733)	Indirect

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	35261	Indirect

Holdings (Derivative)

Security	Exercise Price	Expiration	Underlying	Shares	Ownership
Non-Statutory Stock Option	$1	2005-12-11	Common Stock (10000)	10000	Direct
Warrants	$0.3	2009-07-31	Common Stock (200000)	200000	Direct
Warrants (Series A)	$0.2	2012-09-10	Common Stock (300000)	300000	Direct
Warrants (Series A2)	$0.2	2013-06-12	Common Stock (150000)	150000	Direct
8-1/2% Senior Convertible Preferred Stock	$		Common Stock (188500)	188500	Direct
8-1/2% Senior Convertible Preferred Stock	$		Common Stock (47000)	47000	Indirect

Footnotes

F1: Gift to The Gardner Family Foundation.

F2: Reporting person disclaims beneficial ownership of shares and warrants owned by spouse.

F3: The shares of the 8-1/2% Senior Convertible Preferred Stock are convertible into Common Stock on a one-for-one basis.

F4: Immediately convertible.

F5: Not applicable.