Clarksville and Noark soils, which are on side slopes, have more than 35 percent coarse fragments in the control section and do not have a fragipan. Gepp soils, which are on upland side slopes, have a very-fine control section and do not have a fragipan. Nixa soils, which are on ridgetops, have more than 35 percent coarse fragments in the control section. Moderately well drained. Runoff is high or high.
Permeability is slow.
Native vegetation was hardwood forests with small openings of tall grass prairies. Ozark Highlands of Arkansas, Oklahoma, Missouri, and possibly Kentucky, Tennessee, and West Virginia. The series is of large extent. These soils could be classified as Oxyaqauic Fragiudults, but there is currently no such classification in Soil Taxonony. Mineralogy data from the NSSL supports the classification.