Twelve 34" x 27" map sheets; each map depicts a different data theme for the 4-state area of Missouri, Illinois, Indiana, and Kentucky; 13-page report includes text and 12 figures. An interactive map and downloadable GIS data are available on the Illinois Geospatial Data Clearinghouse: https://clearinghouse.isgs.illinois.edu/data/geology/geologic-and-geoph….