"Wisconsin" loess over extensive erosion surface cut on pre-Illinoian till (tck)
Peoria Loess in Nebraska and southeastern South Dakota; "Wisconsin" and older loess in Iowa
"Wisconsin" loess over Yarmouth-Sangamon paleosol developed in pre-Illinoian clay loam till (tck)
"Wisconsin" loess over Sangamon or late Sangamon paleosol developed in Loveland Loess over Yarmouth paleosol developed in pre-Illinoian clay loam till (tck)