The Wilderness Act (Public Law 88-577, September 3, 1964) and related acts require the U.S. Geological Survey and the U.S. Bureau of Mines to survey certain areas on Federal lands to determine the mineral values, if any, that may be present. Results must be made available to the public and to be submitted to the President and Congress. This report presents the results of geologic studies in the Sangre de Cristo Wilderness Study Area in the Rio Grande and San Isabel National Forests, south-central Colorado. The area was designated as a wilderness study area under Public Lay 96-560 in 1980.