The Octagon series consists of moderately well drained soils that formed in Wisconsinan age calcareous glacial till on till plains and moraines. They are very deep soils that are moderately deep to dense glacial till. Octagon soils may have as much as 18 inches of silty material at the surface or a cap of fine sandy loam sediments is possible in some areas.
Permeability is moderate in the solum and moderately slow to very slow in the dense glacial till.
These soils are on moraines and till plains. Slopes range from 2 to 20 percent. Octagon silt loam - on a 5 percent slope in a cultivated field at an elevation of 710 feet. The depth to carbonates ranges from 24 to 40 inches. Thickness of the silty material ranges from 0 to 18 inches.