Includes geological cross-section. Scale approximately 1:1,800,000. Adapted from Regional Geologic Map series, Indiana Geological Survey; drafted by Roger L. Purcell.
Purcell, Roger L. (1970). Map of Indiana showing bedrock geology. Indiana Geological Survey. https://purl.dlib.indiana.edu/iudl/images/VAC3073/VAC3073-M-00975 (map)