Petty Ray Geophysical, Gillette, WY No description specified. 1-2 (2 Records) Documents Letter Report: An Intensive Cultural Resource Survey of the Petty Ray Geophysical Seismic Line 81-A-49, Campbell and Converse Counties, Wyoming (1981) Letter Report: An Intensive Cultural Resource Survey of the Petty Ray Seismic Line #81-A-31, Campbell and Converse Counties, Wyoming (1981)