The Tarr series consists of very deep, excessively drained soils formed in siliceous sandy pedisediment over siliceous sandy residuum from sandstone on stream terraces, hills, and pediments.
Permeability is rapid.
Slope ranges from 0 to 60 percent. Mean annual precipitation is about 30 inches. Thickness of the solum ranges from 20 to 40 inches. The weighted average content of silt plus clay is 5 percent or less in the particle-size control section but is more than 5 percent in the upper 10 to 20 inches of the series control section. The sand fraction is more than 90 percent quartz or other non-weatherable minerals.