Dawson Geophysical and TGC Industries  have terminated the definitive merger agreement pursuant to which Dawson would have acquired TGC in a tax-free stock-for-stock transaction.

As of the result of the 10-day volume weighted average price for Dawson’s stock as of October 25, 2011 falling outside the designated range specified in the merger agreement, Dawson and TGC engaged in discussions and exchanged letters concerning possible adjustments to the merger exchange ratio of Dawson stock for TGC stock prior to and on October 26 and 27, 2011.  However, the parties were unable to reach agreement regarding an adjustment to the exchange ratio.

Dawson Geophysical Company is a provider of U.S. onshore seismic data acquisition services.

TGC Industries  provides project management for acquisition of 3D seismic data.