DAWSON GEOPHYSICAL CO — Director's Dealing 2005

May 3, 2005

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: TGC INDUSTRIES INC (TGCI)
CIK: 0000799165
Period of Report: 2005-04-29

Reporting Person: HURTT WILLIAM C JR (Director, 10% Owner)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2005-04-29	Common Stock	S	10000	$4.10	Disposed	398700	Direct
2005-04-29	Common Stock	G	5000	—	Disposed	393700	Direct
2005-05-02	Common Stock	G	10000	—	Disposed	383700	Direct

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	10800	Indirect

Holdings (Derivative)

Security	Exercise Price	Expiration	Underlying	Shares	Ownership
Warrants (Series A)	$.20	2012-09-10	Common Stock (371000)	371000	Direct
Warrants (Series A2)	$.20	2013-06-12	Common Stock (162329)	162329	Direct
Warrants (Series C2)	$1.00	2007-12-15	Common Stock (5200)	5200	Direct
8-1/2% Senior Convertible Preferred Stock	$		Common Stock (375000)	375000	Direct

Footnotes

F1: Not applicable

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

F3: Includes 15,700 shares of common stock held in Reporting Person's IRA.

F4: Includes 71,000 additional shares of common stock issuable upon exercise, resulting from application of the warrants' anti-dilution provisions as a result of the PIK dividends paid on the Company's 8-1/2% Senior Preferred Stock.

F5: Includes 12,329 additional shares of common stock issuable upon exercise, resulting from application of the warrants' anti-dilution provisions as a result of the PIK dividends paid on the Company's 8-1/2% Senior Preferred Stock.

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

F7: Immediately convertible.