Shows soil types classification by colors and symbols. 'Field Operations, Bureau of Chemistry and Soils, 1927.' 'Litho Eastern Offset Inc., Balto.' Scale 1:63,360. 1 inch = 1 mile. U.S. Department of Agriculture, Bureau of Chemistry and Soils; Purdue University, Agricultural Experiment Station; soils surveyed by W.E. Tharp, U.S. Department of Agriculture, and D.R. Kunkel, Purdue University Experiment Station.