LOCATION TIMHILL OKEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, thermic Lithic Haplustolls
TYPICAL PEDON: Timhill stony silt loam--forest.
(Colors are for dry soil unless otherwise stated.)
A--0 to 7 inches; dark brown (10YR 3/3) stony silt loam,
very dark grayish brown (10YR 3/2) moist; moderate medium granular structure; hard, very friable; many fine and a few medium roots;
many fine and medium pores; rhyolite fragments make up about 35 percent by volume; neutral; gradual wavy boundary. (4 to 8 inches thick)
Bw--7 to 15 inches; dark brown (7.5YR 4/2) very gravelly silt loam, dark brown (7.5YR 3/2) moist; moderate medium and fine
granular structure; hard, friable; few fine and medium roots; rhyolite fragments make up about 40 percent by volume; neutral;
clear wavy boundary. (5 to 9 inches thick)
C--15 to 18 inches; yellowish red (5YR 5/6) very gravelly
loam, yellowish red (5YR 4/6) moist; massive; few fine roots; rhyolite fragments make up about 80 percent by volume; slightly
acid; abrupt irregular boundary. (1 to 3 inches thick)
R--18 to 30 inches; indurated rhyolite tilted 40 degrees from horizontal.
TYPE LOCATION: Murray County, Oklahoma; about 6 miles south and
1/2 mile west of Davis; 1,300 feet south and 800 feet west of the northeast corner of sec. 1, T. 2 S., R. 1 E.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 9 to 17 inches. Depth to indurated rhyolite bedrock ranges from 10 to 20 inches.
The A horizon has hue of 7.5YR or 10YR, value of 3 to 5, and
chroma of 2 or 3. It is stony silt loam or stony loam. Content
of coarse fragments make up 25 to 50 percent by volume. About 15
to 25 percent by volume is less than 76 mm in diameter, and 10 to
25 percent by volume is more than 76 mm in diameter. Reaction is medium acid to neutral.
The B horizon has hue of 5YR or 7.5YR, value of 3 to 5, and chroma
of 2 to 4. It is very gravelly silt loam, very gravelly loam,
cobbly silt loam, or cobbly loam. Content of coarse fragments
make up 35 to 65 percent by volume. About 35 to 50 percent by
volume is less than 76 mm in diameter, and 0 to 15 percent by
volume is more than 76 mm in diameter. Reaction is medium acid to neutral.
The C horizon has hue of 2.5YR or 5YR, value of 4 or 5, and chroma
of 3 to 6. It is very gravelly loam. Content of coarse fragments make up 70 to 80 percent by volume and are less than 76 mm in diameter. Reaction is slightly acid.
The R layer is indurated rhyolite that is tilted more than 20
degrees from horizontal.
COMPETING SERIES: These are the
Brewster,
Eckert,
Kiti,
Lampshire, and
Palopinto series in the same family and the
Aledo,
Atascosa,
Eckrant,
Shidler,
Woodford, and
Yates series of similar families. Brewster, Eckert, Lampshire, and Palopinto soils lack B horizons and are dry for longer periods of time. In addition, Eckert, Kiti, and Palopinto soils are more alkaline in reaction. Also, Kiti soils formed over tilted limestone. Aledo soils have carbonatic mineralogy and are more alkaline in reaction. Atascosa soils have an argillic horizon. Eckrant soils have more than 35 percent clay content in the control section. Shidler soils have
less than 35 percent coarse fragments. Woodford soils have
siliceous mineralogy and formed over tilted sandstone. Yates
soils lack a mollic epipedon.
GEOGRAPHIC SETTING: Timhill soils are on the highest parts of the Arbuckle Mountains. They are on the sloping tops and the strongly sloping to steep shoulder and back slopes. The soil formed in material weathered from tilted rhyolite of Cambrian age. Slopes
are 5 to 30 percent. The climate is subhumid. Mean annual precipitation is 36 to 38 inches. Mean annual temperature ranges from 62 to 64 degrees F. Thornthwaite annual P-E indices range
from 46 to 62.
GEOGRAPHICALLY ASSOCIATED SOILS: These are soils of the competing Kiti series. The Kiti soils are on similar areas.
DRAINAGE AND PERMEABILITY: Timhill soils are well drained.
Runoff is rapid, and permeability is moderate.
USE AND VEGETATION: Used mainly for rangeland. The vegetation consists of post oak, blackjack oak, sumac, and buckbrush with a sparse understory of tall and midgrasses.
DISTRIBUTION AND EXTENT: Arbuckle Mountains of Oklahoma. The
series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Murray County, Oklahoma; 1982.
ADDITIONAL DATA: Oklahoma State University laboratory data 77-OK-50-5.