Swanboy and Twotop soils are on fans, footslopes, and upland valleys below the Wasa soils. They have bedrock below depths of 40 inches. In addition, Twotop soils have salts at a depth of 10 and 20 inches. Slickspots, which are void of vegetation, are usually closely associated with the Wasa soils. Runoff is low on nearly level areas to very high on sloping areas.
Permeability is very slow.
Native vegetation is mainly western wheatgrass and montana wheatgrass. The series is of moderate extent.