DAWSON GEOPHYSICAL CO — Director's Dealing 2005

Oct 13, 2005

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: TGC INDUSTRIES INC (TGCI)
CIK: 0000799165
Period of Report: 2005-10-11

Reporting Person: FLYNN EDWARD L (Director, 10% Owner)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2005-10-11	Common Stock	M	10000	$1.00	Acquired	928516	Direct
2005-10-12	Common Stock	C	188500	—	Acquired	211316	Indirect

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2005-10-11	Non-statutory Stock Option	$1.00	M	10000	Disposed	2005-12-10	Common Stock (10000)	Direct
2005-10-12	8-1/2% Senior Convertible Preferred Stock	$	C	188500	Disposed		Common Stock (188500)	Indirect

Holdings (Derivative)

Security	Exercise Price	Expiration	Underlying	Shares	Ownership
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)	$.20	2013-06-12	Common Stock (162329)	162329	Direct
Warrants (Series C2)	$1.00	2007-12-15	Common Stock (5200)	5200	Direct

Footnotes

F1: Reporting person disclaims beneficial ownership of shares owned by spouse.

F2: 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.

F3: 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.

F4: The shares of the 8-1/2% Senior Convertible Preferred Stock are convertible into Common Stock on a one-for-one basis.

F5: Immediately convertible.

F6: Not applicable.