U.S.G.S. Rock Bluff, Iowa-Nebr. Aquic moisture regime. Overwash phases are 6 to 18 inches thick and are silt loam or silty clay loam with 20 to 40 percent clay and 1 to 8 percent sand. There are no other series in the same family. Carlow soils have thinner mollic epipedons and are more acid.
Chequest soils have thinner mollic epipedons and are more acid.
Darwin soils have thinner mollic epipedons. Kings soil has mollic epipedons less than 20 inches thick, and are shallower to carbonates. Rantoul soils formed in fine textured drift that is high in sand content. Portage soils average more than 60 percent clay in the family control section and are more acid. Woodbury soils have silty clay loam texture in the lower part of the B horizons and the C horizons.