They formed in residuum and colluvium derived from volcanic rocks such as rhyolite and rhyolitic tuff. Slopes are 2 to 50 percent. Elevations range from 4,500 to 6,200 feet. The mean annual precipitation is 4 to 8 inches, the mean annual temperature is 49 to 53 degrees F., and the frost-free period is 100 to 140 days. These are the Singatse , Stewval , and Theon soils.
Singatse soils are loamy-skeletal and are very shallow to lithic contacts.
Stewval soils are loamy-skeletal, very shallow and shallow to lithic contacts, have argillic horizons, and are in an aridic moisture regime bordering xeric. Theon soils are loamy-skeletal, very shallow and shallow to lithic contacts, and have argillic horizons. Goldyke soils are used for rangeland and wildlife habitat. The present vegetation is mainly Bailey greasewood, galleta, spiny menodora, bud sagebrush, spiny hopsage, shadscale, and Indian ricegrass. These soils are moderately extensive.