The beach stands at 680 feet (210 m) above sea level west of the hinge line, unaffected by the isostatic rebound.
Lake Warren was preceded by a lower stage, which had its outlet through the Mohawk valley.
The beach is horizontal from Lenox, in St. Clair county, around the west end of Lake Erie, then along the south shore through Ohio to the Pennsylvania line, a distance of 300 miles (480 km).
The ridges are well developed in a few areas well beyond the Plateau in the Lakes Erie and Ontario lowlands.
In many cases, the ridges and deltas are underlain by silts of Lake Whittlesey lakebed.