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: BARRETT WILLIAM J (Director, 10% Owner)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2005-10-11	Common Stock	M	10000	—	Acquired	744676	Direct
2005-10-12	Common Stock	C	709200	—	Acquired	1453876	Direct
2005-10-12	Common Stock	C	75500	—	Acquired	128731	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	2005-12-11	Common Stock (10000)	Direct
2005-10-12	Warrants	$.30	S	200000	Disposed	2009-07-31	Common Stock (200000)	Direct
2005-10-12	Warrants (Series A)	$.20	S	371000	Disposed	2012-09-10	Common Stock (371000)	Direct
2005-10-12	Warrants (Series A2)	$.2	S	162329	Disposed	2013-06-11	Common Stock (162329)	Direct
2005-10-12	8-1/2% Sr. Conv. Preferred Stock	$	C	709200	Disposed		Common Stock (709200)	Direct
2005-10-12	8-1/2% Sr. Conv. Preferred Stock	$	C	75500	Disposed		Common Stock (75500)	Indirect

Holdings (Derivative)

Security	Exercise Price	Expiration	Underlying	Shares	Ownership
Warrants (Series C2)	$1.00	2007-12-15	Common Stock (5200)	5200	Indirect

Footnotes

F1: The Reporting Person disclaims beneficial ownership of shares and warrants 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 Prefered Stock are convertible into Common Stock on a one-for-one basis.

F5: Immediately convertible.

F6: Not applicable.

F7: Warrants were sold to Company pursuant to a warrant purchase agreement that defined the sales price of each warrant as the price at which the Company's Common Stock was sold in the Company's public offering on October 6, 2005, less the exercise price of the Warrants (the "in the money value") and an amount equal to underwriting discounts and commissions of 6.5% on the in the money value.