Lake Chicago -The Ancient Shorelines

Vast amounts of sand in spits, dunes and beach lines—particularly at the southern tip of Lake Michigan—were left behind by each of the three stages of lake level drop. Today, evidence of these vast sand deposits are still clearly visible.  many of the Chicago area's trails and roads follow some of these ancient beach lines or ridges in the sand spits.

For example, Ridge Road from Homewood, Illinois, through Thornton and Lansing, Illinois, and then crossing the state border into Munster and Highland, Indiana, is one; Michigan City Road through Riverdale, Dolton, and Calumet City, Illinois, is another; LaGrange Road is another; Riverside Drive in Riverside; Ridgeland Avenue in Oak Park, or Grosse Point Road, Carpenter Road, and Ridge Avenue (The Rosehill Spit) in the Rogers Park/West Ridge neighborhood of Chicago, north of Devon Avenue and continuing north through Evanston, Illinois, are some others. Blue Island, Illinois, and Stony Island were, literally, islands left behind as Lake Chicago's water level fell.