The Madaus series consists of very deep, very poorly drained soils formed in herbaceous organic materials overlying marly material and sand deposits on outwash plains, lake plains and terraces, flood plains, moraines, and till plains. Permeability is moderately slow to moderately rapid in the organic material, slow in the marly material, and rapid in the sandy material. Slopes range from 0 to 1 percent. Madaus muck, on a less than 1 percent slope in a cultivated field. Thickness of the organic surface layer ranges from 7 to 16 inches.
Reaction ranges from slightly acid to moderately alkaline.
The Lma horizon has hue of 10YR to 5Y, value of 4 to 8 and chroma of 1 to 4. Reaction is slightly alkaline or moderately alkaline. The 2Cg or 2C horizon has hue of 10YR, 5Y, or 2.5Y, value of 4 to 7 and chroma of 1 to 4. It is loamy sand, fine sand, sand, or coarse sand and their gravelly analogues. Rock fragment content ranges from 0 to 25 percent.