LOCATION FOSSILON                WY+MT

Inactive Series
Rev. WRG/CJF
10/2013

FOSSILON SERIES

Typically, Fossilon soils have very pale brown, calcareous, channery clay loam A1 horizons and very pale brown, calcareous, channery silty clay loam C horizons that overlie hard marlstone at a depth of 15 inches,

TAXONOMIC CLASS: Loamy-skeletal, carbonatic Lithic Haplocryepts

TYPICAL PEDON: Fossilon channery clay loam - rangeland (Colors are for air-dry soil unless otherwise stated.)

A1--0 to 4 inches; very pale brown (10YR 7/3) channery clay loam, brown (10YR 5/3) moist; moderate very fine granular structure; slightly hard, very friable, sticky, plastic; many fine roots; 40 percent coarse fragments; calcareous; moderately alkaline (pH 8.3); clear wavy boundary. (2 to 6 inches thick)

AC--4 to 8 inches; very pale brown (10YR 7/3) channery silty clay loam, pale brown (10YR 6/3) moist; moderate fine subangular blocky structure; slightly hard, very friable, sticky, plastic; many fine roots; 40 percent coarse fragments; calcareous; moderately alkaline (pH 8.3); gradual wavy boundary. (O to 5 inches thick)

C--8 to 15 inches; very pale brown (10YR 8/3) channery silty clay loam, very pale brown (10YR 7/3) moist; moderate very fine angular blocky structure; slightly hard, very friable, sticky, plastic; 40 percent coarse fragments; calcareous; moderately alkaline (pH 8.4). (4 to 10 inches thick)

R--15 to 18 inches Hard marlstone.

TYPE LOCATION: Lincoln County, Wyoming; SW1/4 of Sec. 14, T22N, R118W.

RANGE IN CHARACTERISTICS: The mean annual soil temperature is 38 degrees to 41 degrees F. The mean summer soil temperature is 55 degrees to 58 degrees F. Depth to hard marlstone or limestone is 6 to 20 inches. Limestone or marlstone channery is 35 to 50 percent. Calcium carbonate equivalent including channery less than 20 mm. in diameter is more than 40 percent. The A and C horizons have hue of 2.5Y through 10YR; value of 6 through 8 dry, 5 through 7 moist; and chroma of 2 or 3. These horizons are channery loam, channery silt loam, channery clay loam, or channery silty clay loam. These horizons are moderately or strongly alkaline.

COMPETING SERIES: These are the Starman (T) and Prow (T) series. Starman soils have mixed mineralogy and are calcareous. Prow soils formed in soft marlstone and have less than 35 percent channery.

GEOGRAPHIC SETTING: Fossilon soils are on high ridges and hillsides. Slopes are 0 to 60 percent. These soils formed in residuum weathered from marlstone or limestone. Elevation is 7,200 to 8,000 feet. Average annual precipitation is 12 to 15 inches. Mean annual temperature is 38 degrees to 43 degrees F. The mean summer temperature is 54 degrees to 58 degrees F. Frost-free season is 30 to 60 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These include the Prow and Redmanson soils. Redmanson soils have a mollic epipedon.

DRAINAGE AND PERMEABILITY: Well drained. Slow to rapid runoff. Moderately slow permeability.

USE AND VEGETATION: Used as rangeland, recreation, and wildlife habitat. The native vegetation is low sagebrush, thickspike wheatgrass, Sandberg bluegrass, bluebunch wheatgrass, Indian ricegrass, winterfat, and in some areas mahogeny.

DISTRIBUTION AND EXTENT: Present known distribution limited to southwestern Wyoming. The soils are believed to be inextensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES PROPOSED: Lincoln County (Fossil Butte National Monument), Wyoming; 1974. Fossilon made inactive on 10/28/2013.

REMARKS: These soils were formerly classified as Lithosols.

OSED scanned by NSSQA. Last revised by state on 4/74.

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National Cooperative Soil Survey
U.S.A.