Great Lakes Origin by Diastrophic Processes

Great Lakes Area Formerly Submerged

Evidence of former submergence is present around the Great Lakes and the Canadian Shield. There are ancient shorelines on the sides of hills, including wave eroded beaches and shore bluffs. Some of these shorelines are not horizontal, and the slope of strand lines is greater for the highest and earliest ones, and increases towards the northeast in the area of the Great Lakes.

Discoveries of whale fossils in Michigan, also walrus, and whale and seal fossils from the drift in Ontario indicate former submergence of the area below sea level.