[en] The Gallup 1⁰ x 2⁰ quadrangle includes portions of 5 major geologic structures which from east to west are: (1) the San Juan Basin; (2) the Zuni Uplift; (3) the Gallup Sag; (4) the Defiance Uplift; and (5) the Black Mesa Basin. Portions of the Mount Taylor and Hopi Buttes Volcanic Fields are present in the southeastern corner and the eastern edge respectively. Most exposed rocks in the quadrangle are Mesozoic and Tertiary sediments, and Quaternay surficial units, with minor amounts of Paleozoic and Precambrian rocks within the uplifts. Uranium ore is currently being produced from the large Jurassic and Cretaceous sandstone deposits in the Smith Lake and Gallup Mining Districts. Scattered uranium occurrences exist in various Precambrian, Paleozoic and Mesozoic rocks throughout the quadrangle. A total of 129 groups of statistically anomalous uranium samples were defined as anomalies and discussed in the report. Several anomalies are associated with the major uranium districts. Others are associated with geologic units known to contain uranium occurrences in the quadrangle and elsewhere. The largest number of anomalous samples occur in scattered exposures of surficial deposits, and in the Triassic Chinle Formation near the quadrangle's western edge. Magnetic data generally outline the major geologic structures, except where overlying Tertiary volcanics obscure the deeper magnetic sources. Some magnetic responses outline areas which do not reflect structure as mapped by Hackman and Olson (1977) on the Dakota Sandstone Base, and may result from deeper magnetic sources