” North of the watershed between the Ohio River and the St. Lawrence drainages, Ohio is a fiat plain. It is an old lake bed, rising in shallow steps from the present shore of Lake Erie. The north edge of each “step” is marked by a “Lake Ridge,” a fossil beach marking a stage in the recession of the post-glacial lake. In a few places wave, action has cut a slight terrace where the old shore line met steeper than average terrain, but along most of the extent the “ridges” mark barrier beaches between the lake and a lagoon. Here they are as distinct as a railroad embankment would be. There are three main ridges continuous across the state; these mark the longest pauses in the recession. In prehistoric times these were the main east and west trails, and today are followed along much of their length by the main east and west highways.