From abstract: In 1951 uranium deposits containing carnotite were discovered in the southern Black Hills near Edgemont, Fall River County, S. Dak. Many carnotite deposits have since been found in sandstones in the Inyan Kara group of Early Cretaceous age, and uranium-bearing material has been discovered in the Minnelusa sandstone of Pennsylvanian age and the Deadwood formation of Cambrian age in the southern Black Hills. Ore has been produced only from the Inyan Kara group, mostly within an area of about 30 square miles along the southwest flank of the Black Hills uplift between Dewey and Hot Springs, in Custer and Fall River Counties. In addition, occurrences of uranium in other parts of the Black Hills and the surrounding area are known or reported in sedimentary, igneous, and metamorphic rocks of pre-Cambrian to Tertiary age.