Tentative Series


The soils have brown, slightly acid, gravelly loam A horizons; strongly acid light clay Bt horizons and pale brown, neutral C horizons.

TAXONOMIC CLASS: Fine, smectitic, thermic Ultic Haploxeralfs

TYPICAL PEDON: Newtown gravelly loam _ range. (Colors for dry conditions unless otherwise noted)

A1--0 to 8 inches; brown (7.5YR 5/4) gravelly loam, dark brown (7.5YR 4/4) moist; massive; slightly hard, friable, nonplastic, nonsticky; abundant very fine roots; many very fine tubular and interstitial pores, few fine tubular pores; slightly acid (pH 6.2); clear sooth boundary.

A3--8 to 18 inches; mottled very pale brown (10YR 7/4) and brown (7.5YR 5/4) very gravelly clay loam, dark brown (7.5YR 5/4) moist; massive; hard, friable, slightly plastic, slightly sticky; few very fine and fine, abundant medium roots; many very fine tubular pores; slightly acid (pH 6.2); clear smooth boundary.

B2t--18 to 35 inches; brown (7.5YR 5/4) light clay with common medium distinct yellowish red mottles, dark brown (7.5YR 4/4) moist, with manganese stains in pores and on ped faces; moderate medium angular blocky structure; very hard, firm, very plastic, sticky; few fine, abundant medium roots; common very fine tubular pores; continuous moderately thick clay films on ped faces and in pores; strongly acid (pH 5.5); gradual smooth boundary.

B3t--35 to 65 inches; pale brown (10YR 6/3) silty clay loam, with common medium distinct dark brown mottles, dark yellowish brown (10YR 4/4) moist with manganese stains in pores and on ped faces; weakly coarse angular blocky structure; weakly cemented, very hard, firm,plastic, sticky; plentiful medium roots; few very fine tubular pores; continuous moderately thick clay films on ped faces; slightly acid (pH 6.5); gradual smooth boundary.

C--65 to 85 inches; pale brown (10YR 6/3) light silty clay loam with common medium reddish brown mottles; strong brown (7.5YR 5/6) moist; massive; weakly cemented, very hard, friable, plastic, slightly sticky; plentiful medium roots; many very fine tubular pores; few thin clay films in pores; neutral (pH 7.0)

TYPE LOCATION: In Shasta County, California about 2 1/2 miles south of Olinda; 1,300 feet north northwest of the SE corner, Sec. 34, T.30N, R.5W.

RANGE IN CHARACTERISTICS: The A1 horizon ranges in color from brown and yellowish brown to pale brown and light yellowish brown (7.5YR, 10YR) dry and moist colors are about one unit of value darker; in texture from sandy loam to gravelly loam, and in reaction from strongly acid to slightly acid. The B2t horizon ranges in color from light brown and strong brown to brown and reddish yellow with moist colors about one unit of value darker; in texture from heavy clay loam to silty clay and in reaction from strongly acid to medium acid.

COMPETING SERIES: These include the Clough, Corning, Hillgate, Newville, Millsap, Olivenhain, Perkins, Positas, and Supan series. The Clough soils have very gravelly Bt horizons and indurated hardpans. The Corning soils have yellowish red A horizons and abrupt AB boundaries. The Perkins soils have yellowish red, neutral Bt horizons, Positas soils have umbric epipedons, and abrupt A/B boundaries, and the Supan soils have thick, dark reddish brown A horizons and dark reddish brown clay loam Bt horizons.

GEOGRAPHIC SETTING: The Newtown soils occur on gently sloping to very steeply sloping old terraces of the Tuscan-Tehama sediments. Elevations range from 600 feet to 1,000 feet. The climate is subhumid mesothermal with mean annual rainfall of 25 to 35 inches, with hot dry summers and cool moist winters. Mean annual temperature is about 60 to 63 degrees F., average January temperature about 42 degrees F., and average July temperature about 80 degrees F.

GEOGRAPHICALLY ASSOCIATED soils: Newtown soils occur in the same general area as the Churn, Corning, Igo, Newville, Perkins, Red Bluff and Redding soils.

DRAINAGE AND PERMEABILITY: Well drained, slowly permeable, medium to rapid runoff.

USE AND VEGETATION: Used for grazing. Vegetation is blue oak, live oak, digger pine, manzanita, annual grasses and forbs.

DISTRIBUTION AND EXTENT: Occur in western and central Shasta County where they are moderately extensive.


SERIES PROPOSED: Shasta Area, California 1965. Name from a town in Shasta County.

REMARKS: The Newtown series was formerly classified in the Noncalcic Brown group. Present classification is based on an ochric epipedon, an argillic horizon with base saturation less than 75 percent and a mean annual temperature between 59 and 69 degrees F.

OSED scanned by SSQA. Last revised by state on 2/66.

National Cooperative Soil Survey