DAWSON GEOPHYSICAL CO — Director's Dealing 2004

Oct 19, 2004

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: TGC INDUSTRIES INC (TGCI)
CIK: 0000799165
Period of Report: 2004-10-18

Reporting Person: USELTON KENNETH W (Secretary and Treasurer)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2004-10-18	Common Stock	M	4000	$0.75	Acquired	9224	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2004-10-18	Stock Option	$0.75	M	4000	Disposed	2004-10-19	Common Stock (4000)	Direct

Holdings (Derivative)

Security	Exercise Price	Expiration	Underlying	Shares	Ownership
Stock Option	$0.8	2009-02-19	Common Stock (6000)	6000	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.