They formed in moderately fine textured parent materials weathered from platy shales and limestones. At the type location the average annual precipitation is 20 inches. There is no frost-free period. These are the Basquez, Haverly , and Ptarmigan soils. These soils are very strongly acid, and have umbric epipedons.
Poor drainage is often due to seepage water.
These soils are used as rangeland or for recreational purposes. Principal native vegetation is willows, sedges, and water-tolerant plants. The series is of small extent. Gunnison County, Colorado, 1975.