Reaction of the B horizon ranges from medium to strongly acid except in the IIIB horizon which ranges from neutral to medium acid. The IIIB horizon has formed in residuum weathered from limestone. It commonly has hue of 5YR, value of 3 or 4, and chroma of 3 or 4. The IIIB horizon commonly is 2 to 6 inches thick but ranges to 10 inches in thickness. In pedons that contain the upper boundary of the IIIB horizon within 40 inches the thickness of the IIIB horizon is 5 inches or less.
Texture is silty clay or clay with a variable content of chert.
Clay content commonly ranges from 55 to 70 percent. These are the Arbor , Atkinson , Ayr , Burchard , Calmar , Corwin , Cresco , Door, Durand , Foresman , Friesland , Griswold , Hochheim , Jasper , Joslin , Kankakee , La Rose , Linkville , Markesan , Mona , Morrill , Norborne , Pana , Parr , Plattville , Ringwood , Rockton , Rotamer , Shelby , Sibleyville , Symerton , Tippecanoe , Velma , Wea , and Winnebago series. All of the soils except Atkinson, Calmar, Plattville, and Rockton and Sibleyville lack a lithic or paralithic contact within depths of 60 inches. Atkinson and Plattville soils lack 5YR or redder hue in the lower sola. Calmar, Rockton, and Sibleyville soils have a lithic or paralithic contact at depths less than 40 inches.