Over thousands of years, Lake Michigan changed size many times, leaving the imprints of its former shorelines. It was formed by a lobe of the Wisconsin Glacier, which halted to the south and deposited debris in a ridge or moraine called the Valparaiso Moraine, the most distant ridge line. At the end of the Ice Age, glaciers retreated and readvanced several times, changing lake levels in ancient Lake Michigan; when lake levels rose, the shoreline moved south. The second most distant visible ridge line is Calumet Beach, which was Lake Michigan's shoreline more than 10,000 years ago. About 5,500 years ago, the lake rose again and stood about 23 feet higher than today, and the site is on that ancient beach, Toleston Beach. In the distance, a line of white towers marks the South Shore Line, an electric interurban railroad that began in 1908 and, before automobiles, brought Chicago residents to the Dunes.

Photo: Lou Donkle

Beverly Shores, Indiana · USA