20231213 16503400 1.0 TRUE Bedrock Geology Current interpretation of bedrock stratigraphic units at the bedrock surface, mapped primarily at the stratigraphic Group level, characterized by distinctive rock types. Should be used with Iowa Bedrock Faults. Additional information at: http://www.igsb.uiowa.edu/webapps/gsbpubs/pdf/ofm-2010-1_txt.pdf