The Bruncan series consists of shallow to duripan, well drained soils with moderately slow permeability that formed in mixed silty alluvium and loess from basalt and volcanic ash.
Bruncan soils are on tablelands, calderas, structural benches, plains and buttes.
Slopes range from 0 to 15 percent. The surface has about 3 percent stone cover. These are the Acana , Argalt , Ayres , Bartome , Chuckridge , Chuska , Colthorp , Dewar , Grassval , Handpah , Packwood , Pipeline , Roseworth , Thoms and Wellington series. Acana, Ayres, Bartome, Chuckridge, Chuska, Dewar, Handpah, Grassval, Pipeline, Roseworth, Thoms and Wellington soils lack bedrock above 40 inches. Argalt soils are less than 10 inches deep to bedrock.