Superior Shoal

The Superior Shoal is a geologic shoal of approximately 20 square miles (52 km2) located 50 miles (80 km) north of Copper Harbor, Michigan in the middle of Lake Superior, the highest point of which lies only 21 feet (6.4 m) below the lake's surface.

[1] The shoal is a hump of Keweenawan basaltic lava flows with ophitic interiors and amygdaloidal tops in an otherwise deep part of the lake, and though fishermen had known of its existence for generations it was only officially charted in 1929 by the United States Lake Survey.

[2]: 193  It has been theorized that the World War I French minesweepers Inkerman and Cerisoles, which disappeared during their maiden voyage on Lake Superior in mid-November 1918, may have run aground on this shoal[2]: 192  and some have theorized that it may have been to blame for both the disappearance of the "Flying Dutchman of the Great Lakes" on November 21, 1902, and the sinking of the "Titanic of the Great Lakes" on November 10, 1975 (the SS Bannockburn and SS Edmund Fitzgerald, respectively).

[3][4] It is one of the known off-shore spawning and foraging habitats for the juvenile lean lake trout.

[5] A different shoal with the same name is located just off Delf Island in Georgian Bay east of Lake Huron in Ontario.