[en] Between October 23 and November 9, 1978, Aero Service Division Western Geophysical Company of America conducted a high sensitivity airborne gamma-ray spectrometer and magnetometer survey over the 2⁰ x 1⁰ NTMS quadrangle of Cortez, Colorado and Utah. The survey area is bounded by the 108⁰ W and 110⁰ W meridians and the 37⁰ N and 38⁰ N parallels, and is located in the Four Corners area. Traverse spacing throughout the survey area was 3 miles and tie lines were flown 12 miles apart. The standard traverse and tie line orientations of respectively E-W and N-S, used for the entire NURE Airborne Radiometric Reconnaissance program, were maintained in this survey. The Cortez area, to the east of the Comb Ridge, consists mainly of Jurassic and Cretaceous terrane, in part covered by Quaternary alluvial, colluvial and eolian deposits. The Upper Jurassic Morrison formation is probably the most famous host rock of uranium and vanadium ores in the United States. In particular its Salt Wash member, but also the Brushy Basin and the Recapture members contain numerous uranium mines and deposits in the Colorado Plateau area. The area to the west of the Comb Ridge forms part of the Monument Uplift. This area is underlain by Upper Paleozoic and Triassic strata. The Triassic Chinle formation is another famous producer of uranium and vanadium ore of the Colorado Plateau, in particular in Utah and Arizona. Most of the uranium mines and deposits appear concentrated in the various conglomerate members of the Chinle, such as the basal Shinarump, the Moss Back and the Monitor Butte members. Twelve appendices are included