Version history for Ashley, Roger P., and Rytuba, James J., 2008, Mercury geochemistry of gold placer tailings, sediments, bedrock, and waters in the lower Clear Creek area, Shasta County, California; report of investigations, 2001-2003: U.S. Geological Survey Open-File Report 2008-1122 [http://pubs.usgs.gov/of/2008/1122/]. Version 1.0, July 31, 2008 Initial release online at http://pubs.usgs.gov/of/2008/1122/ October6, 2008 Shapefile and metadata added by JW.