Shows soil types classification by colors and symbols. 'Field operations Bureau of Chemistry and Soils 1930. 'Williams & Heintz Co. Wash. D.C.' Scale 1:63,360. 1 inch = 1 mile. Soils surveyed by C.S. Simmons and R.T. Avon Burke, U.S. Department of Agriculture, and T.M. Bushnell, J.E. Adams and H.P. Ulrich, Purdue University Agricultural Experiment Station.