A till plain is an extensive flat plain of glacial till that forms when a sheet of ice becomes detached from the main body of a glacier and melts in place, depositing the sediments it carried. Ground moraines are formed when the till melts out of the glacier in irregular heaps, forming rolling hills.
^Simonson, Bruce. "Geology of the Vermilion River Watershed." Living in the Vermilion River Watershed. Ed. Mary C. Garvin. Chardon, OH: POV Communication, pp. 8-12.