LOCATION INVERNESS CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, active, isomesic Ultic Haplustalfs
TYPICAL PEDON: Inverness loam - on a west-facing concave slope of 5 percent under hardinggrass, coyotebrush, plantain, and velvetgrass at 1,100 feet elevation. (Colors are for dry soil unless otherwise stated. When described (9/14/76) the soil was moist throughout.)
A11--0 to 10 inches; very dark grayish brown (10YR 3/2) loam, black (10YR 2/1) moist; strong very fine, fine and medium subangular blocky structure; slightly hard, friable, sticky and plastic; many very fine and fine, common medium roots; few very fine and fine tubular and interstitial pores; strongly acid (pH 5.5); gradual smooth boundary. (5 to 15 inches thick)
A12--10 to 22 inches; very dark grayish brown (10YR 3/2) loam, black (10YR 2/1) moist; strong fine, medium and coarse subangular blocky structure; slightly hard, friable, sticky and plastic; many very fine and fine, common medium roots; common very fine and fine tubular and interstitial pores; strongly acid (pH 5.5); clear smooth boundary. (8 to 15 inches thick)
B2t--22 to 29 inches; brown (10YR 5/3) clay loam, very dark brown (10YR 2/2) moist; strong medium and coarse subangular blocky structure; hard, friable, sticky and plastic; common very fine and fine roots; common very fine and fine tubular and interstitial pores; few thin clay films in pores and on peds; strongly acid (pH 5.5); clear smooth boundary. (5 to 10 inches thick)
B3t--29 to 36 inches; light yellowish brown (10YR 6/4) heavy clay loam, dark yellowish brown and very dark grayish brown (10YR 4/4, 3/2) moist; strong medium and coarse subangular blocky structure; hard, very friable, sticky and plastic; common very fine and fine roots; few very fine and fine interstitial, common very fine and fine tubular pores; common thin clay films in pores and on peds; strongly acid (pH 5.5); clear smooth boundary. (5 to 10 inches thick)
C1--36 to 47 inches; very pale brown (10YR 7/4) loam, yellowish brown (10YR 5/4) moist; weak coarse subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; common very fine and fine tubular and interstitial pores; about 5 to 10 percent mica; moderately acid (pH 5.8); clear smooth boundary. (8 to 15 inches thick)
C2--47 to 60 inches; very pale brown (10YR 7/4) loam, light yellowish brown (10YR 6/4) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; common very fine and fine tubular and interstitial pores; about 20 percent mica; moderately acid (pH 5.8); gradual smooth boundary. (10 to 15 inches thick)
C3r--60 to 70 inches; very pale brown (10YR 7/4) strongly weathered soft granitic rock.
TYPE LOCATION: Marin County, California; Point Reyes National Seashore; 1 mile northwest from Vortax Station on Mt. Vision Road, 1,000 feet southwest on fire road from Mt. Vision Road, 20 feet north of fire road.
RANGE IN CHARACTERISTICS: Depth to paralithic contact of weathered granite is 40 to 60 inches or more. The mean annual soil temperature is 52 degrees to 57 degrees F. The difference between mean summer and mean winter soil temperature is less than 9 degrees F. The soil moisture control section is usually moist in all parts from mid-November to mid-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. The particle-size control section averages less than 35 percent clay. Reaction is strongly acid or moderately acid with pH increasing with increasing depth. Base saturation ranges from 35 to 50 percent throughout the soil.
The A horizon has dry color of 10YR 4/1, 4/2 or 3/2 and moist color of 10YR 2/1, 2/2, 3/1 or 3/2.
The Bt horizon has dry color of 10YR 4/2, 5/2, 5/3, 6/2, 6/3 or 6/4 and moist color of 10YR 3/2, 4/2, 5/2, 5/3, 2/2 or 4/4. It is clay loam or heavy clay loam.
The C horizon has dry color of 10YR 7/3, 7/4 or 6/4 and moist color of 10YR 6/3, 6/4 or 5/4. It is loam or sandy loam and is massive or has weak subangular blocky structure. It contains about 5 to 20 percent mica and the soil has a smooth or "greasy" feel due to the mica.
COMPETING SERIES: This is the Steinbeck series in another family. Steinbeck soils have a mesic soil temperature and a thick A2 horizon.
GEOGRAPHIC SETTING: The Inverness soils occur on hills and mountains. Slopes are 9 to 75 percent. Elevations are 250 to 1,200 feet. The soils form in residuum weathered from granite. The climate is subhumid mesothermal with cool, foggy summers and cool, moist winters. Mean annual precipitation is 25 to 35 inches. Mean January temperature is about 52 degrees F., mean July temperature is about 55 degrees F., and the mean annual temperature is about 52 degrees to 57 degrees F. The frost-free season is about 300 to 365 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bayview and Pablo soils. Bayview and Pablo soils are less than 20 inches deep to a lithic contact.
DRAINAGE AND PERMEABILITY: Well drained; moderate runoff; moderate permeability.
USE AND VEGETATION: This soil is used for rangeland, recreation, wildlife habitat, and watershed. Natural vegetation is shrubs, annual grasses, forbs, and widely spaced pines.
DISTRIBUTION AND EXTENT: Upland areas of central coastal California. The soils are of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Marin County, California, 1979.
REMARKS: The activity class was added to the classification in February of 2003. Competing series were not checked at that time. - ET