Thoms soils are slightly acid or neutral throughout. Bartome soils are on summits and side slopes of fan piedmont remnants. These soils formed in alluvium from mixed sources with a thin loess cap. Slopes are 0 to 8 percent. Elevations are 4,800 to 6,000 feet.
Climate is cool and semiarid with warm, dry summers and cool, moist winters.
These are the competing Colthorp soils and the Buffaran , Chiara , Ramires and Wedertz soils. Buffaran and Ramires soils have more than 35 percent clay in their argillic horizons. Ramires and Wedertz soils lack an indurated duripan. Chiara soils lack an argillic horizon and have less than 15 percent fine sand or coarser in their control section. Livestock grazing and wildlife habitat.