These are the Baltic, Holly Springs , James , and Nishna series in the same family and the Blue Earth, Okoboji , and Wacousta series. Baltic soils contain gypsum crystals and are more clayey. Holly Springs soils have buried silty clay or clay horizons. Nishna soils formed in alluvium on first bottom lands and has a sand content of 5 to 15 percent or less. Blue Earth soils have a higher content of organic matter.
Okoboji soils are noncalcareous.
Wacousta soils are noncalcareous and have a solum thickness of 10 to 24 inches. Knoke soils are in depressions on till or lacustrine plains. Many of the depressions held shallow lakes, most of which have been drained since settlement. Slope gradients typically are less than 1 percent. These soils formed in glacial sediments.