LOCATION INSKIP CAEstablished Series
TAXONOMIC CLASS: loamy-skeletal, isotic, mesic Typic Dystroxerepts
TYPICAL PEDON: Inskip extremely rocky silt loam, forested. (Colors for dry soil unless otherwise stated)
A11--0 to 6 inches; dark brown (10YR 3/3) gravelly silt loam, very dark brown (10YR 2/2) moist; weak fine granular structure; soft, very friable, slightly sticky, slightly plastic; many very fine and fine roots; many very fine pores; angular fragments of vesicular basalt occupy 20 to 50 percent of the volume; neutral; clear smooth boundary. (2 to 8 inches thick.)
A12--6 to 15 inches; dark yellowish brown (10YR 4/4) very gravelly loam, dark yellowish brown (10YR 3/4) moist; weak fine granular structure; soft, very friable; slightly sticky, slightly plastic; very fine and fine roots; many very fine pores; about 50 percent by volume of rock fragments; neutral; gradual smooth boundary. (8 to 15 inches thick.)
C--15 to 26 inches; yellowish brown (10YR 5/4) very gravelly loam, dark brown (7.5YR 3/4) moist; weak very fine granular structure; soft, friable; nonsticky, nonplastic; few very fine, fine, and medium roots; porous; 50 percent by volume of rock fragments; neutral; gradual smooth boundary. (10 to 20 inches thick.)
R--26 inches; Fractured fine textured vesicular basaltic lava with soil similar to horizon above partially filling the interstices; weathered surfaces of fractured rock are yellowish-brown; few large roots.
TYPE LOCATION: Tehama County, California, two miles northwest of Paynes Creek on the north slope of Inskip Hill in the SW1/4 of section 23, T29N, R1W.
RANGE IN CHARACTERISTICS: The solum is about 10 to 23 inches thick and depth to vesicular bedrock is about 20 to 43 inches. The fragments of bedrock in the soil are porous and range in size from gravel to stone. Rock outcrops are common. Soil temperature is about 54 to 57 degrees and mineralogy is mixed.
The soils are dry during the summer months most years between depths of 8 and 28 inches.
The A11 horizon has colors in lOYR and 7.5YR hues with values of 3 to 5 dry and 2 or 3 moist. Chromas are 2 or 3 moist and dry.
The A12 and C horizons have colors in the lOYR hue with values of 4 or 5 dry and 3 moist. Chroma is 4. Textures are gravelly or very gravelly loam or silt loam, structure is weak granular, and consistence is soft, friable, slightly sticky and slightly plastic. Reaction is neutral throughout.
COMPETING SERIES: In similar families and subgroups are the Hambright, Henneke, Iron Mountain, and Toomes series. The Hambright soils have basalt bedrock at 16 inches and the Henneke soils have serpentine bedrock at 19 inches. The Iron Mountain soils have tuff-breccia at 9 inches and the Toomes soils have tuff-breccia at 12 inches.
GEOGRAPHIC SETTING: The Inskip soils occur in sloping to steep mountainous areas on relatively recent lava flows. They occur at elevations of 1,000 to 5,000 feet, in a humid mesothermal climate with mean annual rainfall of 35 to 50 inches, with hot dry summers and cool wet winters. Mean annual temperature is about 54 degrees, average January temperature about 38 degrees, and average July temperature about 70 degrees. Frost-free season averages about 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: The deep Cone soils on cinders, and the Supan soils with argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained with moderately rapid permeability and slow runoff.
USE AND VEGETATION: Used for rangeland, and for timber production in a few areas. Vegetation mostly is shrubs and scattered conifers with grasses and forbs in the openings. Conifers include digger pine, knobcone pine, ponderosa pine, and Douglas fir.
DISTRIBUTION AND EXTENT: In the Cascade Range in northern California on recent lava flows. The soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Tehama County, California.
REMARKS: These soils formerly were placed in the Regosol group. Series description was entered into Ames 04/2000. The classification was updated in February 2001 using the Eighth Edition to Soil Taxonomy. This series was formerly classified as loamy-skeletal, mixed, mesic Dystric Xerochrepts. Lab data was not available at that time, this soil may be Vitrandic or Andic subgroup. Competing series were not checked at that time.