LOCATION CASROCK CAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Pachic Ultic Haploxerolls
TYPICAL PEDON: Casrock fine sandy loam, on a southwest facing 20 percent slope under a cover of Douglas fir, California bay laurel, oak and poison oak at an elevation of 879 meters. When described the soil was moist throughout. (Colors are for dry soil unless otherwise noted).
Oi--0 to 2 inches, (0 to 4 cm); very dark brown (10YR 2/2) rubbed slightly decomposed plant material, very dark brown (10YR 2/2) rubbed moist; abrupt smooth boundary. 2 to 7 centimeters thick)
A1--2 to 4 inches, (4 to 10 cm); grayish brown (10YR 5/2) broken face fine sandy loam, very dark grayish brown (10YR 3/2) broken face moist; 12 percent clay; weak fine subangular blocky structure; slightly hard, very friable, nonsticky, slightly plastic; common fine roots; many very fine interstitial pores; 10 percent subangular strongly cemented 2 to 75 millimeter sandstone fragments; moderately acid, pH 5.9 by pH meter 1:1 water; clear smooth boundary. (9 to 15 centimeters thick)
A2--4 to 13 inches, (10 to 33 cm); grayish brown (10YR 5/2) broken face cobbly fine sandy loam, very dark grayish brown (10YR 3/2) broken face moist; 12 percent clay; weak fine subangular blocky structure; slightly hard, very friable, nonsticky, slightly plastic; common fine roots and common medium roots; many very fine interstitial pores; 10 percent subangular strongly cemented 2 to 75 millimeter sandstone fragments and 15 percent subangular strongly cemented 75 to 210 millimeter sandstone fragments; very strongly acid, pH 4.7 by pH meter 1:1 water; clear smooth boundary. (20 to 30 centimeters thick)
AC--13 to 30 inches, (33 to 76 cm); brown (10YR 5/3) broken face cobbly fine sandy loam, dark brown (10YR 3/3) broken face moist; 10 percent clay; massive; soft, very friable, nonsticky, nonplastic; common fine roots and common medium roots and common coarse roots; many very fine interstitial pores; 20 percent subangular strongly cemented 2 to 75 millimeter sandstone fragments and 30 percent subangular strongly cemented 75 to 210 millimeter sandstone fragments; very strongly acid, pH 5.0 by pH meter 1:1 water; abrupt wavy boundary. (20 to 32 centimeters thick)
R--30 to 32 inches, (76 to 82 cm); Strongly cemented coarse grained sandstone bedrock, unfractured.
TYPE LOCATION: Santa Clara County, California, Skyline County park, along Skyline Blvd., east of road at trailhead and road gate, then south on ridge about 500 feet., in Section 22, Township 8s, Range 3w, UTM Northing 4119635, UTM Easting 582200, Zone 10, NAD83 - U.S.G.S Quad: Castle Rock Ridge, California.
RANGE IN CHARACTERISTICS: Depth to sandstone bedrock is 70 to 85 centimeters. The mean annual soil temperature is 55 to 59 degrees F. The particle size control section averages 10 to 18 percent clay and 35 to 55 percent rock fragments, 35 to 45 percent gravel and 0 to 30 percent cobbles. The soil is not calcareous. Organic matter ranges from 2 to 5 percent to a depth of 20 cm. Base saturation by sum of cations ranges from 35 to 75 percent to a depth of 76 cm. Rock fragments on the surface range from 0 to 20 percent boulders.
The A horizon dry color is 10YR 5/3, 5/2 or 4/3. Moist color is 10YR 3/2 or 2/2. Texture is fine sandy loam, gravelly fine sandy loam and cobbly fine sandy loam. Clay content ranges from 10 to 18 percent. Rock fragments range from 10 to 40 percent gravel, 0 to 15 percent cobbles. Reaction ranges from 4.7 to 6.0.
The AC horizon dry color is 10YR 6/4, 6/3, 5/3 or 5/2. Moist color is 10YR 4/4, 3/3 or 3/2. Texture is very gravelly fine sandy loam, very gravelly sandy clay loam and cobbly fine sandy loam. Clay content ranges from 10 to 18 percent. Rock fragments range from 20 to 45 percent gravel and 15 to 30 percent cobbles. Reaction ranges from 4.1 to 5.6.
COMPETING SERIES: There are the Burnscreek, Frantz, Oland, Schiller and Woolstalf series. Burnscreek, Frantz, Oland, Schiller and Woolstalf series have mean annual air temperatures ranging from 45 to 54 degrees F. Burnscreek soils occur on valley fans and terraces. Franz soils are developed from olivine gabbro. Oland soils are very deep and were developed from granitic rocks. Schiller soils are very deep. Woolstalf soils are deep to a paralithic contact of sedimentary rocks and occur in the southern Sierra Nevada at elevations of 5000 to 8300 feet.
GEOGRAPHIC SETTING: Casrock soils are on mountains, mostly on mountain tops and shoulders. Slopes are 8 to 30 percent. These soils formed in residuum weathered from sandstone. Elevation is 2000 to 3100 feet. Mean annual precipitation is 40 to 50 inches. The mean annual temperature is 55 to 59 degrees F. Frost free season is 200 to 250 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Skyridge(T) and Ben Lomond soils. The Skyridge(T) soils have a lithic contact of sandstone at less than 50 centimeters, Ben Lomond soils have a paralithic contact of sandstone at 100 to 150 centimeters.
DRAINAGE AND PERMEABILITY: well drained; moderately rapid permeability.
USE AND VEGETATION: This soil is used for recreation, watershed and wildlife habitat. Vegetation is Douglas fir, California bay laurel, oak and poison oak.
DISTRIBUTION AND EXTENT: The soils are inextensive and are mapped in Santa Clara county. Major Land Resource Area: 15 -- Central California Coast Range, and 4B Coastal Redwood Belt.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Santa Clara County, California. Source of name from Castle Rock State Park.
REMARKS:
Particle Size Control Section for this pedon: 10 to 30 in. (25 to 76 cm)
Diagnostic horizons and features recognized in this pedon are:
Mollic Epipedon: (2 to 30 in.) (4 to 76 cm)
The soil moisture control section is dry in all parts from about May 15 to October 15 (about 150 days).
ADDITIONAL DATA: NASIS SITE ID: 08ca085641160