United States Geological Survey Report 445

From abstract: A reconnaissance search for uraniferous rocks in the northeastern part of the Wind River Basin was made in July and August 1951 in the course of other work. In addition to Tertiary tuffs and associated lignite, coal, and carbonaceous rocks, some radioactivity anomalies, chiefly in granite, which had been detected by airborne equipment in November 1950, were checked on the ground. A tuff of middle or late Eocene age containing 0.003 percent uranium was as high in uranium as any rock found