Historical Marker
Old Michigan Southern
Historical marker location:
Monroe, Michigan
( Marker is on West 1st Street, 0.2 miles west of Cass Street, on the left when traveling east.)
Michigan is the only state to have two designated "state stones": the Petoskey Stone, which is the state stone of Michigan, and the Isle Royale Greenstone, which is the state gemstone of Michigan. The Petoskey Stone is a fossilized coral that is found primarily in the northern Lower Peninsula, while the Isle Royale Greenstone is a rare mineral found only on Isle Royale in Lake Superior.