Geology and ore deposits of the San Francisco and adjacent districts, Utah

Abstract

The San Francisco district was of recognized importance in the early days of mining in Utah, but its output soon declined and thereafter it attracted little attention until about 1903, when the development of the Cactus mine was undertaken. In August, 1904, S. F. Emmons, then in charge of the division of metalliferous deposits of the Geological Survey, visited the district and determined the area to be covered by a projected topographic map. In 1904 and 1905 Fred McLaughlin completed a topographic map covering the San Francisco and Preuss districts and parts of the Beaver Lake, Rocky, and Star districts, an area of about 175 square miles. In the spring of 1908 Waldemar Lindgren, in charge of the division of metalliferous deposits, visited the San Francisco district and decided that the Survey should make a study of its geology. The writer was assigned to the work of mapping the surface geology and was occupied in this work during part of July, the whole of August, and part of September, 1908. Before the geologic work was completed the renewed activity in the Star district made it desirable that all that district should be included in the geologic study and therefore, in the summer of 1909, W. M. Beaman extended the topographic work to include the more active parts of the Star, Rocky, and Beaver Lake districts that were not included in the previous map. The total area mapped is about 200 square miles. In 1909 the writer was assigned to the study of the ore deposits and spent the greater part of July, the whole of August, and part of September in the district. In 1910 he spent about 10 days in the district and in 1910 and 1911 was engaged in studying other districts in southwestern Utah. Office work on the present report has been in progress since the fall of 1908.