The soils formed in alkaline shale mainly of the Cook Mountain Geologic Formation. Mean annual precipitation ranges from 30 to 40 inches, and mean annual temperature is 67 to 70 degrees F. Frost free days range from 260 to 280 days, and elevation ranges from 300 to 500 feet. Thornthwaite P-E index is 42 to 60. These are the Benchley , Crockett , Elmendorf , Marcelinas , Normangee , and Wilson soils. All of these soils have loamy surface layers and clayey argillic horizons.
Permeability is very slow.
Water enters the soil rapidly when it is dry and cracked, and very slowly when it is moist and the cracks are closed. Runoff is low on slopes less than 1 percent, medium on 1 to 3 percent slopes, high on 3 to 5 percent slopes, and very high on 5 to 8 percent slopes. Cultivated crops are mostly cotton, corn, oats, wheat, and grain sorghum. Rangeland vegetation includes little bluestem, Indiangrass, twoflower trichloris, bristlegrass, sideoats grama, Texas wintergrass, mesquite, and hackberry. The soil is moderately extensive.