DAWSON GEOPHYSICAL CO — Director's Dealing 2005

Mar 24, 2005

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: TGC INDUSTRIES INC (TGCI)
CIK: 0000799165
Period of Report: 2005-03-22

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

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2005-02-01	Common Stock	G	32000	—	Disposed	734676	Direct
2005-03-22	Common Stock	S	2000	$4.85	Disposed	53231	Indirect

Holdings (Derivative)

Security	Exercise Price	Expiration	Underlying	Shares	Ownership
Non-Statutory Stock Option	$1.00	2005-12-11	Common Stock (10000)	10000	Direct
Warrants	$.30	2009-07-31	Common Stock (200000)	200000	Direct
Warrants (Series A)	$.20	2012-09-10	Common Stock (371000)	371000	Direct
Warrants (Series A2)	$.2	2013-06-11	Common Stock (162329)	162329	Direct
8-1/2% Sr. Conv. Preferred Stock	$		Common Stock (709200)	709200	Direct
8-1/2% Sr. Conv. Preferred Stock	$		Common Stock (75500)	75500	Indirect
Warrants (Series C2)	$1.00	2007-12-15	Common Stock (5200)	5200	Indirect

Footnotes

F1: Gifts to members of Reporting Person's family (not living in same household).

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

F3: Not applicable.

F4: Includes 71,000 additional shares of Common Stock issuable upon exercise (pursuant to application of the Warrants anti-dilution provisions) resulting from the PIK dividends paid on the Company's 8-1/2% Senior Convertible Preferred Stock.

F5: Includes 12,329 additional shares of Common Stock issuable upon exercise (pursuant to application of the Warrants anti-dilution provisions) resulting from the PIK dividends paid on the Company's 8-1/2% Senior Convertible Preferred Stock.

F6: The shares of the 8-1/2% Senior Convertible Prefered Stock are convertible into Common Stock on a one-for-one basis.

F7: Immediately convertible.

F8: Not applicable.