Hindu soils form from limestone or calcareous sedimentary rocks, have a control section dominated by cobbles, and a moisture control section that is moist in some part for more than 20 days cumulative between June and September. Hulda soils are in the 8 to 10 inch precipitation zone. Noble Pass soils formed in rhyolitic parent material. Pearce soils are in the 8 to 12 inch precipitation zone, have finer textures and have calcium carbonate equivalents of 5 to 35 percent. Razorback soils are in the 6 to 12 inch precipitation zone, formed from extrusive igneous rocks and have finer textures.
Tecopa soils form from mixed metamorphic and igneous rocks such as schist, gneiss, and quartzite.
In addition, they have thinner epipedons, contain a larger proportion of medium and finer sands, and are dry during the summer months. Terlingua soils have horizons with accumulations of secondary calcium carbonate and formed in volcanic rock. Upspring soils form from basic igneous rocks with some pyroclastic material, have a control section that ranges from very gravelly to very stony, and are dry in the moisture control section during the summer. The Dalvord soils are on mountains, hills, and pediments. Slope ranges from 8 to 75 percent.