From introduction: Mapping, sampling, and radiometric reconnaissance of the uranium-bearing deposits in the Laramie formation in the vicinity of the Old Leyden coal mine, sec. 28, T. 2 S., R. 71 W., Jefferson County, Colorado (fig. 1), was completed August 10, 1951. Topographic and geologic maps were made of areas approximately 6,000 feet by 3,000 feet (scale 1:2h00), and 1,200 feet by 800 feet (scale 1:600). Underground workings at three clay mines and at the Old Leyden mine were also mapped. With the exception of the 1:600 map, which accompanies this report, these maps will be transmitted later with a more comprehensive report.