A few erratic boulders occur in Devil's Lake State Park. Eskers , serpentine ridges of gravel and sand, probably mark stream channels under stagnant ice sheets. The well known Parnell Esker is in the Kettle Moraine unit. Kames are conical hills formed by debris deposited by meltwater flowing into funnel-shaped holes in the ice. White Kame is in the Kettle Moraine Unit.
Kettles are surface depressions formed as sand and gravel settled over a melting ice block.
Greenbush Kettle , in the Kettle Moraine unit, is an outstanding example. Potholes were worn into solid rock at falls and strong rapids where sand, gravel, and stones were spun around by the current. Large potholes are found at Interstate Park. The Driftless Area . For unknown reasons, southwestern Wisconsin escaped the ravages of glaciation.