Illinois--a flat and boring state with nothing but cornfields and crowded expressways, right? Balderdash! Geology Underfoot in Illinois scratches the Prairie State"s surface to expose geologic diversity that stretches back more than a billion years. Enjoy an unexpected exploration of Chicago"s architectural geology. Embark on a fault-seeking expedition in Mark Twain"s big-river country. Or try moraine-surfing on Interstates 55 and 74. Copious illustrations and witty, page-turning prose guide readers on geologic walking or driving tours of thirty-seven sites in Illinois.