The moderately well drained Tamalco soils and the somewhat poorly drained Darmstadt soils are on similar nearby or adjacent prominent ridges and formed in similar parent materials. Parke soils lack a mollic epipedon and have less than 40 inches of loess in the upper part of the solum. The moderately well drained Tamalco soils and the somewhat poorly drained Darmstadt and Oconee soils are on lower convex ridges and on foot slopes surrounding Douglas soils. In addition, Darmstadt and Tamalco soils have a high content of exchangeable sodium in the subsoil. Runoff is medium.
Permeability is moderate.
Most areas are cultivated. Corn, soybeans, small grain, and meadow are the principal crops. Native vegetation was prairie grasses. Douglas soils are in southern Illinois. They have a small extent.