Maps showing anomaly patterns for silver, molybdenum, lead, and zinc in altered rocks and soils, Williams Fork and St. Louis Peak Roadless Areas, Clear Creek, Grand, and Summit counties, Colorado

The U.S. Geological Survey and the U.S Bureau of Mines conducted field studies from 1979 through 1982 to assess the mineral resource potential of the Williams Fork and St. Louis Peak Roadless Areas and the Vasquez Peak Wilderness Study Area.  Included were geological, geochemical, and geophysical studies by the U.S. Geological Survey and investigation of known prospects and mines by the U.S. Bureau of Mines.  The area of study is located in the Arapaho National Forest, nort of Interstate Highway 70, west of U.S. Highway 40, and east of the Blue River, on the west side of the Front Range (fig. 1).