“…During the 1940's black shale in various parts of the world was found to be notably radioactive (Russell, 1944(Russell, , 1945Beers and Goodman, 1944;Beers, 1945;McKelvey and Nelson, 1950) and to be a potential source of large quantities of uranium. Because the Chattanooga shale, having about 0.004 to 0.008 percent uranium, is one of the more radioactive shales in the United States, the investigations reported here were conducted by the U. S. Geological Survey at the request and with the support of the Atomic Energy Commission.…”