The marginal ridges or end moraines of the Green Bay Lobe are a result of the accumulation of sediment transported by the glacier. These marginal north–south trending moraines are especially visible in Marathon, Portage, and Waushara Counties. As the Green Bay Lobe melted back into the Green Bay and Fox River lowland, it paused at several positions, forming smaller, yet distinct, moraines that are especially noticeable in Shawano, Marinette, Menominee, and northwest Oconto Counties.
The Johnstown Moraine marks the farthest extent of the ice of the Green Bay Lobe during the last glaciation. This ridge is most apparent at the Baraboo Hills, adjacent to the Central Sand Plains, and north. However, it continues south and east, through Johnstown in Rock County, to mark the southern edge of the ice advance.
© Mountain Press, 2004
