Tharp, W. E. (William Edgar) and Quinn, E. J. (Edward J.)
Shows soil types classification by colors and symbols. 'Field Operations, Bureau of Soils, 1913.' 'A Hoen & Co Lith Baltimore Md.' Scale 1:63,360. 1 inch = 1 mile. U.S. Department of Agriculture, Bureau of Soils; State of Indiana, Department of Geology; soils surveyed by W.E. Tharp of the U.S. Department of Agriculture and E.J. Quinn of the Indiana Department of Geology.