Detroit soils have a thicker mollic epipedon and the argillic horizon contains more than 35 percent clay. Hobbs soils lack a mollic epipedon and are thinly stratified. Hord, Humbarger, and Tobin soils have a mollic epipedon more than 20 inches thick. McCook soils are coarse-silty. Muir soils have a thicker mollic epipedon and more acid upper horizons.
Grigston soils are on flood plains and low stream terraces.
The slope gradient ranges from 0 to 2 percent. The soils formed in calcareous silty alluvium. The mean annual temperature ranges from 50 to 57 degrees F, and the mean annual precipitation ranges from 17 to 28 inches. Thornthwaite annual PE index ranges from 30 to 52. These are the competing Roxbury , Hord , and Detroit soils on similar topography, and the Humbarger and McCook soils on lower areas.