Plate 2 Bedrock Geology, Plate 3, Surficial Geology, Scale 1:100,000. This atlas is a work in progress. Plates 1 and 2 were completed in 2010 as part of the USGS Statemap program.; Surface and subsurface geology of Sibley County; The Sibley County Board of Commissioners; The U.S. Geological Survey Statemap program; The Minnesota Environment and Natural Resources Trust Fund as Recommended by the Legislative-Citizen Commission on Minnesota Resources