Elco and Keller soils formed in 20 to 40 inches of loess and the underlying till that contains a paleosol, with or without a layer of pedisediment in between. In addition, Keller soils have a mollic epipedon. Hickory soils average more than 15 percent sand in the particle-size control section, formed in Illinoian till, and are downslope from Atlas soils. Keomah soils formed in loess and are on convex crests and summits upslope from Atlas soils. Atlas soils are somewhat poorly drained.
Permeability is slow or very slow.
The potential for surface runoff is high to very high. These soils are seasonally wet and seepy. The seasonal high water table is 0.5 foot to 1.5 feet below the surface in spring. Most areas of Atlas soils are used for forage, hay, or pasture. Cultivated crops are on less sloping areas and trees are on steeper areas.