DAWSON GEOPHYSICAL CO — Director's Dealing 2005

Apr 20, 2005

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: TGC INDUSTRIES INC (TGCI)
CIK: 0000799165
Period of Report: 2005-04-18

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

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2005-04-18	Common Stock	P	2500	$3.80	Acquired	22816	Indirect

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	918516	Direct

Holdings (Derivative)

Security	Exercise Price	Expiration	Underlying	Shares	Ownership
Non-statutory Stock Option	$1.00	2005-12-10	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)	$.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 (188500)	188500	Indirect

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.