Relay soils have yellow hue in the B horizon. Westville soils have more sand in the upper B horizons. Pecatonica soils are on till plains and moraines. Slope gradients range from 0 to 30 percent. The sola formed in 15 to 25 inches of loess or silty material and in reddish paleosols formed in glacial drift of Wisconsinan Age.
Summers are hot and winters are cold.
Mean annual temperature ranges from 45 to 57 degrees F., and mean annual precipitation from 28 to 40 inches. Argyle soils which have thicker A horizons, and Durand soils which have mollic epipedons are on the same landscape but are farther from drainageways. Pecatonica soils dominantly are well drained, but the range extends to moderately well drained. Surface runoff is moderate to rapid. Permeability is moderate.