Grant Geophysical Company, Englewood, Co No description specified. 1-2 (2 Records) Documents Cultural Resource Survey for Grant Geophysical Corporation's Paradox Basin Seismic Testing Program Line N0.2, San Miguel and Montrose Counties, Colorado (1983) Grand Geophysical Corporation's Paradox Basin Seismic Testing Program, Line No. 4, San Miguel and Montrose Counties (1983)