You searched for: Place Highway Department causeway south of St. Ignace (later to become north approach of Mackinac Bridge) Remove constraint Place: Highway Department causeway south of St. Ignace (later to become north approach of Mackinac Bridge) Place Michigan Remove constraint Place: Michigan Place North America Remove constraint Place: North America Place USA Remove constraint Place: USA Topic Fungi Remove constraint Topic: Fungi Topic Lichens Remove constraint Topic: Lichens Topic Verrucaria Remove constraint Topic: Verrucaria