Uranium in the Gas Hills area, Fremont and Natrona Counties, Wyoming

Uranium minerals have been discovered in the Wind River formation of early Eocene age, strata of middle and late Eocene age, and the Thermopolis shale of early Cretaceous age in the Gas Hills area of central Wyoming.  The localities of uranium mineralization were found independently by prospectors and by geologists of the Geological Survey; geologists of the Atomic Energy Commission have examined some of the deposits.