Includes generalized columnar section, "Sectionized township," and index of producers of clay and clay products. "Base modified from U.S. Geological Survey, Base map of Indiana, 1950.", Imprint: [Bloomington] : Indiana Geological Survey, 1968., Dimensions: 51 x 64 cm; Scale: 1:1,000,000, Coordinates: W0880500 W0844700 N0414500 N0374600
Ault, Curtis H., Webb, William M. (1968). Locations of clay and shale operations in Indiana. Indiana. Geological Survey. https://purl.dlib.indiana.edu/iudl/images/VAC3073/VAC3073-M-00832 (map)