Original oil and gas trade magazine vintage ad for GEOPHYSICAL SERVICE INC. Main office was located at 900 Exchange Bank Building. Dallas, TX. Alaska, in case you are interested, has an area of 586,400 square miles, was discovered by a Dane, Vitus Bering in 1741, and has the highest peak in North America. You can lessen the tough cold going by discussing your seismic, gravity and magnetic exploration programs with GSI. This unique 1959 old petroleum oilfield drilling exploration magazine advertisement would display beautifully matted and framed. Nice graphics.