Opal soils have bedded shale within depths of 20 to 40 inches. Wendte soils have a fine-textured control section and are adjacent to larger drainageways below areas of Bullcreek soils. Moderately well or well drained. Runoff is medium to very high depending on slope. Permeability is very slow, except after dry periods when initial intake may be rapid due to cracking of the surface.
Flooding is none or rare.
Some pedons have a seasonal water table at a depth of 4 to 6 feet. Principal grasses occur as a thin stand of western wheatgrass and green needlegrass. Central and south-central South Dakota. The series is of moderate extent. These soils were previously correlated as Swanboy in Dewey, Hughes, Stanley, Tripp and Walworth Counties, South Dakota.