Extent is small. Adams County, Illinois, l974. Oxyaquic subgroup based on soil saturation above a depth of 40 inches. Well drained El Dara soils will be included in the Oxyaquic subgroup. It is difficult to differentiate the properties of the lower part of the modern solum from those of the older materials.
Development can go down several feet.
El Dara soils may range to somewhat poorly or poorly drained if a paleosol is present near the surface. As slope and erosion increase, coarse-loamy and sandy textures become dominant and may warrant new series because of the uniqueness of the Cretaceous aged Baylis formation in western Illinois. The Baylis formation resembles the Dakota formation in western Iowa and is composed of layered sand, pink and gray clays, and gravel members. A small area near Wedron, Illinois may also have this type of formation. El Dara was formerly identified as being formed in outwash materials.