LOCATION SCARPER CAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, isomesic Typic Haplustolls
TYPICAL PEDON: Scarper gravelly coarse sandy loam; near Montara on a south-facing slope of 35 percent and at 475 feet. Sage, coyotebrush, yerba-santa, poison oak and annual grasses. (Colors are for dry soil unless otherwise noted. When described September 29, 1983, the soil was slightly moist below 5 inches.)
A1--0 to 5 inches; dark grayish brown (10YR 4/2) gravelly coarse sandy loam, very dark brown (10YR 2/2) moist; weak fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine, and few medium roots; many fine and medium pores; 25 percent 2 to 75 mm pebbles; moderately acid (pH 6.0); clear smooth boundary. (4 to 10 inches thick)
A2--5 to 16 inches; very dark grayish brown (10YR 3/2) gravelly coarse sandy loam, very dark gray (10YR 3/1); weak fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine, few medium roots; many fine and medium interstitial pores; 15 percent 2 to 75 mm pebbles; slightly acid (pH 6.5); clear irregular boundary. (10 to 15 inches thick)
C--16 to 25 inches; brown (7.5YR 4/2) gravelly coarse sandy loam, dark brown (7.5YR 3/2) moist; massive, slightly hard, very friable, slightly sticky and slightly plastic; few fine roots; many fine and medium interstitial pores; 15 percent 2 to 75 mm pebbles; slightly acid (pH 6.5); clear irregular boundary. (6 to 15 inches thick)
Cr--25 inches; weathered quartz diorite that slakes easily in water.
TYPE LOCATION: San Mateo County, California; 7,700 feet east and 1,500 feet north of Point Montara Lighthouse in Montara. The area does not have sections.
RANGE IN CHARACTERISTICS: Depth to a paralithic contact is 20 to 40 inches. The mean annual soil temperature is 56 to 58 degrees F and is usually not below 47 degrees F at any time. Thickness of the mollic epipedon ranges from 14 to 20 inches.
The difference between mean winter and mean summer soil temperature is less than 9 degrees F. The soil moisture control section is moist throughout the solum from mid-November through June. It is dry in some or all parts the rest of the time but is not dry in all parts for 45 consecutive days. Rock fragments throughout the profile range from 15 to 25 percent. Reaction is slightly acid to moderately acid. Organic carbon is 3 to 4 percent throughout. The clay content is 8 to 18 percent throughout.
The A horizon is 10YR 3/2, 4/1, 4/2, 5/1, 5/2, or 5/3 dry and 10YR 2/2, 3/1, 3/2, or 4/3 moist. Textures are gravelly coarse sandy loams.
The C horizon is 7.5YR 4/2, 4/3, 5/2, 5/3; 10YR 4/2, 4/3, 5/2, or 5/3 dry and 7.5YR 3/2; 10YR 3/2 or 4/3 moist. Texture is gravelly coarse sandy loam. This horizon does not meet the requirements for a mollic epipedon.
COMPETING SERIES: These are the Buriburi (T) and Kehoe series in other families. The Buriburi (T) and Kehoe series have a fine-loamy textural control section.
GEOGRAPHIC SETTING: Scarper soils are on steep to very steep coastal uplands and have slopes of 30 to 75 percent. They formed in material weathered from quartz diorite. Elevations are 200 to 1,800 feet. The climate is subhumid with cool, foggy summers and cool, moist winters. Mean annual precipitation is 20 to 45 inches. Mean January temperature is about 48 degrees F and mean July temperature is about 60 degrees F. Mean annual temperature is about 54 to 56 degrees F. Frost-free season is about 275 to 350 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Alambique (T), Barnabe, Bret (T), Buriburi (T), Candlestick (T), McGarvey (T), and Miramar (T) soils. Alambique soils have less than 50 percent base saturation throughout and have sandstone parent materials. Brisbane and Bret soils are less than 20 inches to sandstone. Buriburi and Candlestick soils are fine-loamy and have sandstone parent materials. McGarvey soils have 35 to 60 percent base saturation at the top of the paralithic contact and are in the fine family. Miramar soils are fine-loamy.
DRAINAGE AND PERMEABILITY: Well drained, rapid to very rapid runoff, moderately rapid permeability.
USE AND VEGETATION: Used for wildlife habitat, watershed, and recreation. Vegetation is mostly coastal shrubs and scattered annual grasses and forbs.
DISTRIBUTION AND EXTENT: Northern Santa Cruz Range. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: San Mateo County, California 1984. Source of name is from Scarper Peak, San Mateo County, California.
REMARKS: The base saturation by the Hatch Kit is greater than 75 percent throughout the profile. The sand content is 60 to 70 percent and the clay content is 8 to 18 percent. (Hydrometer method).
The activity class was added to the classification in February of 2003. Competing series were not checked at that time. - ET