[en] Instrumentation and methods described were used for a Department of Energy (DOE) sponsored high-sensitivity, aerial gamma-ray spectrometer and magnetometer survey of the Trinidad, Colorado, NTMS, 1:250,000-scale quadrangle. The survey was carried out by Texas Instruments Incorporated under Bendix Field Engineering Corporation Subcontract No. 79-263-L. Objective of the work was to define areas showing surface indications of a generally higher uranium content where detailed exploration for uranium would most likely be successful