LOCATION ROCKHOUSE               TX

Established Series
Rev. ERB:JCW
10/2012

ROCKHOUSE SERIES

The Rockhouse series comprises deep, well drained, rapidly permeable soils on nearly level floodplains. These soils formed in very gravelly, cobbly, and stony alluvium from igneous hills and mountains. Slopes range from 0 to 3 percent.

TAXONOMIC CLASS: Sandy-skeletal, mixed, thermic Fluventic Haplustolls

TYPICAL PEDON: Rockhouse loam--rangeland. (Colors are for dry soil unless otherwise stated.)

A--0 to 12 inches; dark grayish brown (10YR 4/2) loam, very dark grayish brown (10YR 3/2) moist; weak granular structure; slightly hard, friable; many roots; many fine pores; a few subrounded igneous pebbles, cobbles, and stones; neutral; clear smooth boundary. (6 to 18 inches thick)

C1--12 to 20 inches; grayish brown (10YR 5/2) very cobbly loamy sand, very dark grayish brown (10YR 3/2) moist; weak granular structure; few roots; 70 percent by volume of subrounded igneous fragments consisting of about 30 percent gravel, 30 percent cobbles and 10 percent stones; neutral; diffuse wavy boundary. (6 to 15 inches thick)

C2--20 to 60 inches; grayish brown (10YR 5/2) very cobbly sand, very dark grayish brown (10YR 3/2) moist; single grained; few roots; 70 percent by volume of subrounded igneous fragments comprising about 30 percent gravel, 30 percent cobbles, and 10 percent stones; neutral.

TYPE LOCATION: Jeff Davis County, Texas; 20 miles northeast of Fort Davis; in Rock House canyon 0.1 mile west of junction of State Highway 17 and Ranch Road 1832.

RANGE IN CHARACTERISTICS:

Soil moisture: Aridic ustic moisture regime.

Depth to bedrock: more than 40 inches

Thickness of the mollic epipedon: 10 to 20 inches thick

Reaction: slightly acid to slightly alkaline.

A horizon
Hue: 7.5YR or 10YR
Value: 3 to 5
Chroma: 2 or 3
Texture: sandy loam or loam, or gravelly and cobbly counterparts of these. Coarse fragments: 5 to 40 percent, with 5 to 40 percent gravel, 2 to 20 percent cobbles, and 0 to 10 percent stones.

C horizons
Hue: 7.5YR or 10YR
Value: 4 or 5
Chroma: 2 to 4
Texture: loamy sand or sand
Coarse fragments: 35 to 80 percent, with 20 to 50 percent gravel, 10 to 40 percent cobbles and 0 to 25 percent stones
Reaction: neutral to moderately alkaline
Calcium carbonate: noncalcareous to calcareous. In some pedons a few carbonates are in faint films or coatings on the coarse fragments.

COMPETING SERIES: There are no competitors.

GEOGRAPHIC SETTING: These soils are on level flood plains of high gradient streams that drain igneous hills and mountains. Slope gradients are usually less than 1 percent, but range to 3 percent. They have developed in very gravelly, cobbly, and stony alluvium in which most of the coarse fragments are largely from igneous formations. The elevation is 3,500 to 5,500 feet. Annual rainfall ranges from 8 to 20 inches and annual air temperature 60 degrees to 70 degrees F.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bigetty, Boracho, Brewster, Espy, Limpia, Liv, Mainstay, Medley, Mitre, and Santo Tomas series. Bigetty and Medley have fine-loamy control sections. Boracho, Espy, and Mitre soils are shallow over a petrocalcic horizon. Brewster and Mainstay are shallow over igneous bedrock. Limpia soils have an argillic horizon and are clayey-skeletal. Santo Tomas soils are loamy-skeletal.

DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; rapid permeability.

USE AND VEGETATION: Used for livestock grazing and wildlife habitat. Moderate cover of mid and short grasses such as plains bristlegrass, blue grama, and bush muhly with overstory mainly of catclaw.

DISTRIBUTION AND EXTENT: West Texas. MLRA 42. The series is of moderate extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona

SERIES ESTABLISHED: Jeff Davis County, Texas; 1971.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Mollic epipedon - the A horizon from 0 to 12 inches.

Fluventic feature - irregular decrease of organic matter in C horizons.

Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Eleventh Edition, 2010

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National Cooperative Soil Survey
U.S.A.