These are the Exira , Keg , Marshall , Monona , Nira , Northboro , Ponca , Port Byron , Raddle , Sac , Salix , and Truman series in same family and the Moody , Sharpsburg , and Tama series. Exira soils have a mottle-free zone less than 12 inches thick below the mollic epipedon. Keg and Salix soils commonly have colors with chroma of 2 in the B horizon, are shallower to free carbonates, and have more variable coarse silt-fine silt ratios, being formed in silty alluvium. Marshall soils have a slightly lower maximum clay content and stronger structure in the B horizon tend to be more acid and are leached of free carbonates to greater depths and have formed in thicker loess. Monona, Raddle, and Truman soils have silt loam texture throughout the solum.
Nira soils have a grayer B horizon, being formed in deoxidized loess.
Northboro soils have redder hues and higher sand content in their solum. Ponca soils are shallower to free carbonates. Port Byron soils have less clay and are more acid. Sac soils have more sand in the lower part of the Bw horizon which formed in clay loam glacial till. Moody soils have segregated lime at shallower depths and are formed in a drier climate with lower annual precipitation.