Established Series


The Oglesby series consists of shallow, well drained, slowly permeable soils. These soils formed in residuum of weathered limestone and marine sediments over limestone bedrock. Slopes are dominantly less than 3 percent and range from 0 to 3 percent.

TAXONOMIC CLASS: Clayey, smectitic, thermic Lithic Haplustolls

TYPICAL PEDON: Oglesby silty clay, on a plane surface in rangeland. (Colors are for dry soil unless otherwise stated.)

A1--0 to 6 inches; very dark grayish brown (10YR 3/2) silty clay, very dark brown (10YR 2/2) moist; weak medium subangular blocky and granular structure; hard, firm; many very fine, fine, and few medium roots; common fine pores; mildly alkaline; gradual smooth boundary. (5 to l8 inches thick)

A2--6 to 16 inches; very dark grayish brown (10YR 3/2) silty clay, very dark brown (10YR 2/2) moist; moderate medium angular and subangular blocky structure; hard, firm; common fine and few medium roots; common pressure faces and few small slickensides; 5 percent limestone fragments 2 inches to 6 inches across; mildly alkaline; abrupt wavy boundary. (0 to 10 inches thick)

R--16 to 24 inches; indurated limestone with a hardness by Mohs scale of 3 or more; upper part has coarse fractures filled with soil material, below the bedrock has tight fractures and it cannot be excavated with a backhoe machine.

TYPE LOCATION: Coryell County, Texas; from the intersection of Farm Road 182 and Farm Road 217 about 1.0 mile north of Turnersville; 4.9 miles east on Farm Road 182; 1.1 miles southeast on county road; 200 feet west in rangeland.

RANGE IN CHARACTERISTICS: The solum thickness and depth to bedrock range from 10 to 20 inches. The average clay content is 40 to 50 percent. Limestone fragments less than 3 inches to about 25 inches across range from none to a few on the surface up to about 10 percent by volume in the solum. Some pedons have a few chert fragments of similar size. The reaction is neutral or mildly alkaline and noncalcareous. The dry soil cracks more than 1 cm wide throughout and has a COLE of more than 0.07. The soil is dry in some part of the moisture control section for less than 90 cumulative days in most years.

The A horizon has hue of 7.5YR or 10YR, value of 2 or 4, and chroma of 1 or 2. The A2 horizon ranges from 5YR to 10YR with value of 3 or 4 and chroma of 1 to 4. The A1 and A2 horizons are silty clay or clay.

The R horizon is inducted limestone that is coarsely fractured.

COMPETING SERIES: These are the Harper series in the same family. Similar soils include Eckrant, Purves, Stephen and Tarrant series. Harper soils are dry in some part of the moisture control section for more than 90 cumulative days in most years. Eckrant and Tarrant soils have over 35 percent coarse fragments in the control section, and in addition Tarrant soils have a calcic horizon. Purves soils have a calcic horizon and are calcareous throughout. Stephen soils have mixed mineralogy and are underlain by a paralithic contact of chalky limestone.

GEOGRAPHIC SETTING: Oglesby soils are on nearly level or gently sloping uplands. Surfaces are typically plane to slightly benched with slopes of 0 to 3 percent. Oglesby soils formed mainly in the Kiamichi Clay and Edwards Limestone undivided formations of the Lower Cretaceous Period. Mean annual precipitation ranges from 26 to 34 inches. The mean annual temperature is 64 to 68 degrees F. Frost free days range from 220 to 260 days and elevation ranges from 850 to 1250 feet. Thornthwaite P-E indices range from 44 to 56.

GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing Eckrant series and the Bolar, Crawford, and Denton series. Eckrant soils are on similar positions. Bolar soils are moderately deep, loamy soils on side slopes, and ridgetops, upslope from Oglesby soils. Crawford soils have a sola 20 to 40 inches thick and are on similar surfaces. Denton soils are deep soils on side slopes, upslope from Oglesby soils.

DRAINAGE AND PERMEABILITY: Well drained. Runoff is slow to medium; Permeability is slow;

USE AND VEGETATION: Mainly range. Present native vegetation includes sideoats grama, Texas wintergrass, threeawn and buffalograss. Woody vegetation includes post oak, elm, hackberry and a few scattered live oak.

DISTRIBUTION AND EXTENT: Central Texas, in the southern part of the Grand Prairie and in the Blackland Prairie. The series is moderately extensive.


SERIES ESTABLISHED: Coryell County, Texas; l983.

REMARKS: Reaction determined by glass electrode. Diagnostic horizons and features recognized in this pedon are:

Mollic epipedon - 0 to 16 inches (A1 and A2 horizons)

Lithic contact - interface of soil and limestone at 16 inches

National Cooperative Soil Survey