In October, 1854, schooners Defiance and John J. Audubon collided in a fog off Presque Isle. Both vessels quickly sank and now rest intact on the bottom of Lake Huron. This image shows a sonar scan of John J. Audubon, which went down with a cargo of railroad iron bars. Along with its masts and deck structure, scattered railroad iron can be seen on the lake floor surrounding the vessel.