LOCATION PEBBLEPOINT TXEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, mixed, active, thermic Udic Paleustalfs
TYPICAL PEDON: Pebblepoint very gravelly sandy loam, on 7 percent slopes--rangeland. (Colors are for dry soil unless otherwise stated.)
A1--0 to 4 inches; dark grayish brown (10YR 4/2) very gravelly sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; slightly hard, very friable; many fine roots; about 40 percent chert pebbles, mostly 1 to 2 cm across, on the surface and in the soil; few chert cobbles; neutral; clear wavy boundary. (2 to 9 inches thick)
A2--4 to 22 inches; pink (7.5YR 7/4) very gravelly silt loam, brown (7.5YR 5/4) moist; weak fine granular structure; slightly hard, very friable; few fine and medium roots; about 75 percent angular chert pebbles, 1 to 4 cm across; few chert cobbles; strongly acid; clear wavy boundary. (10 to 34 inches thick)
B21t--22 to 40 inches; yellowish red (5YR 5/6) very gravelly clay, yellowish red (5YR 4/6) moist; moderate fine and very fine blocky structure; very hard, very firm; few very fine to medium roots; few fine pores; continuous clay films on faces of peds; about 65 percent angular chert pebbles 1 to 7 cm across; about 5 percent chert cobbles; strongly acid; gradual wavy boundary. (9 to 19 inches thick)
B22t--40 to 65 inches; red (2.5YR 4/6) very gravelly clay, dark red (2.5YR 3/6) moist; moderate very fine blocky structure; very hard, very firm; few very fine roots; continuous clay films on faces of peds; about 80 percent angular chert pebbles 1 to 7 cm across; about 5 percent chert cobbles; strongly acid; gradual wavy boundary. (10 to 31 inches thick)
R--65 to 75 inches; weakly consolidated bed of gravel, cobbles, stones, and boulders of chert that becomes indurated with depth; about 5 percent red clay in the interstices in upper few inches.
TYPE LOCATION: San Saba County, Texas; from the intersection of U. S. Highway 190 and Texas Highway 16 in San Saba, Texas; 5 miles east on U. S. Highway 190, then 0.2 mile south along trail to gate, then 0.6 mile southeast to corral, then northward along fence 0.2 mile, then 600 feet east in rangeland.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 40 to about 70 inches to chert and cherty limestone. A few stones and boulders occur throughout some pedons.
The A1 horizon has a hue of 7.5YR or 10YR, value of 4 or 5, and chroma of 2 or 3. The fine earth fraction is fine sandy loam, loam, or very fine sandy loam. Coarse fragments comprise 35 to 60 percent by volume with 0 to 15 percent larger than 76 mm. Reaction is slightly acid through moderately alkaline.
The A2 horizon has a hue of 7.5YR or 10YR, value of 5 through 8, and chroma of 3 through 6. The fine earth fraction is fine sandy loam, loam, very fine sandy loam, or silt loam. Coarse fragments comprise 40 to 85 percent by volume with 5 to 20 percent larger than 76 mm. Reaction is strongly acid through neutral.
The B2t horizons ranges in hue from 2.5YR through 7.5YR, value from 4 through 6, and chroma from 4 through 8. The fine earth fraction is clay or sandy clay with a clay content of 37 to 60 percent. The B21t horizon contains from 40 to 90 percent coarse fragments and the B22t horizon contains from 50 to 90 percent coarse fragments. Both horizons have from 5 to 20 percent larger than 76 mm included in the coarse fragments. Reaction is strongly acid or medium acid. The boundary between the B22t horizon and the R layer ranges from gradual to diffuse.
The R layer consists of weakly consolidated chert gravel, cobbles, stones and boulders and cherty dolomite that is weathered and fractured in the upper part and rapidly becomes indurated bedrock with depth.
COMPETING SERIES: These are the Riesel series in the same family and the Bexar, Bonti, Castell, Nocken, Rosanky, Rumple, Scullin, Travis, and Voca series. Riesel soils are formed in alluvial gravelly sediments. Bexar and Rumple soils are underlain by limestone at depths of less than 40 inches. Bonti, Chigley, and Scullin soils contain less than 35 percent coarse fragments. In addition, Scullin soils have mollic epipedons. Castell soils contain less than 35 percent coarse fragments and are 20 to 40 inches deep over gneiss. Nocken soils are 20 to 40 inches deep over sandstone. Rosanky and Travis soils have less than 35 percent coarse fragments in the control section. Voca soils developed from weathered granite and contain less than 35 percent coarse fragments, except for the lower part of the Bt horizon.
GEOGRAPHIC SETTING: Pebblepoint soils are on complex slopes on uplands. Slopes range from 3 to 30 percent. The soil formed in residuum from chert and dolomitic limestone uplifted in an irregular to oblong pattern. Outcrops of chert cobbles, stones, and boulders are common on ridge crests, which are usually 30 to 50 yards wide, and on the hillsides below. Mean annual temperature ranges from 64 degrees to 67 degrees F. Mean annual precipitation ranges from 26 to 34 inches. Thornthwaite P-E indices ranges from 38 to 50.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Rumple series and the Leeray, Roughcreek, Tarpley, and Sagerton series. All these soils occur at slightly lower elevations. Rumple, Roughcreek, and Tarpley soils are on adjacent uplands and are underlain with limestone. Roughcreek and Tarpley soils have sola less than 20 inches thick. Leeray and Sagerton soils are in broad valleys or on outwash plains and contain less than 15 percent coarse fragments. In addition, Leeray soils are clayey throughout and have intersecting slickensides.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; slow permeability. A water table is perched on the Bt horizon for a few days following heavy rains.
USE AND VEGETATION: Used as rangeland. Native vegetation is savannah with post oak and blackjack oak trees. Native grasses include little bluestem, indiangrass, big bluestem, sideoats grama, Texas cupgrass, plains lovegrass, purpletop tridens, and annuals.
DISTRIBUTION AND EXTENT: Central Texas. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: San Saba County, Texas; 1980.
REMARKS: These soils would have been classified in the Red and Yellow Podzolic great soil group.