The resistant Niagaran series dolomite and limestone of Silurian age form the Niagaran Escarpment, which is locally exposed as cliffs and limestone pavement along the Lake Michigan shoreline from the Stonington Peninsula in the west to Drummond Island at the far eastern edge of the Upper Peninsula of Michigan, and eastward to Cockburn Island, Manitoulan Island, and the Bruce Peninsula of Ontario. Various landforms of glacial lacustrine origin characterize the sub-subsection, including flat lake bed, deltaic deposits of sand, parabolic dune fields, and shallow embayments containing transverse dunes. Large areas consist of lacustrine sand deposits that have flat to gently undulating surfaces. On this topography, only a few inches of elevation change can greatly alter drainage conditions. Drainage conditions also depend on depth to underlying bedrock or fine-textured substrate.
Ground moraine is locally present.
Exposed limestone and dolomite bedrock forms flat, pavement-like areas, and breccia chimneys are locally exposed. Several large lakes. The largest are on ground moraine, including Manistique and South Manistique Lakes. On the sandy lake plain, there are two large lakes, Millecoquins and Brevoort, and several smaller lakes. On bedrock, or where limestone and dolomite bedrock is near the surface, there are numerous lakes, including Merwin, Gulliver, McDonald, Caribou, and East.