All the series except Cotter, Reading, Toddville, Troxel, and Wiota have mollic epipedons less than 24 inches thick. Cotter soils contain more sand in the lower solum. Reading soils contain more clay in the substratum. Toddville soils are stratified and have more sand in the lower part of the solum. Troxel soils contain more sand in the lower part of the solum.
Wiota soils have more fine and coarser sand in the solum and allow more sandy stratified substrata.
Marshall soils lack an argillic horizon and have a mollic epipedon less than 24 inches thick. Sibley soils are on gently and moderately sloping convex ridgetops and side slopes. Slope gradients are commonly 2 to 9 percent and range from 2 to 14 percent. The soil formed in thick loess deposits. Mean annual temperature ranges from 53 to 57 degrees F., and the mean annual precipitation ranges from 34 to 42 inches.