More than nine-tenths of the Upper Cretaceous rocks in northeastern Wyoming are fine-grained shales, mudstones, and calcareous marls. A comparative study of the mineralogy, chemical and mechanical composition, density and porosity, fissility, and lamination of samples of these rocks discloses several relations that throw light on the geologic history and structural deformation of the region, and perhaps on its oil and gas possibilities.

Report issued by the Bureau of Mines over mineral characteristics, uses, and problems. Descriptions of common minerals and their uses are presented and discussed. This report includes tables, maps, and illustrations.

From deposit: Since 1975 a cooperative effort between the United States Department of Energy, United States Geological Survey, Geological Survey of Wyoming, the Geology Department, University of Wyoming, and various industry groups has resulted in the discovery of a series of uraniumthorium-and gold-bearing conglomerates in Late Archean and Early Proterozoic metasedimentary rocks of southern Wyoming. The mineral deposits were found by applying the time and strata bound model for the origin of uranium-bearing quartz-pebble conglomerates to favorable rock types within a geologic terrane known from prior regional mapping.