Nine hundred and sixty-five natural radioactive occurrences of uranium, some containing thorium, are known for Arizona. Of these, 328 localities were the source of l8.l million pounds of U308 between 1945 and 1970. About 43 million pounds of V205 were present in the uranium ores. Ninety-nine percent of Arizona's total production is from the Triassic-Jurassic sedimentary rocks of the Colorado Plateau, approximately half of which came from the Salt Wash Member of the Morrison Formation in the Carrizo and Lukachukai Mountains. Historically, only a small amount of uranium has been produced from the Basin and Range Province. However, recent exploration has shown significant uranium potential in late Tertiary sediments in this region. Arizona's largest single uranium deposit has been at the Monument No.2 Mine of Apache County. There, about 5.2 million pounds of U308 and nearly eleven million pounds of V205 were produced from a single channel deposit in the Shinarump Member of the Triassic Chinle Formation. (297 pages.)