A team of U.S. wreck hunters, backed by the governments of France and Michigan, has revealed plans to dive next month to a site on the bottom of Lake Michigan, where one of the most important ships in Canadian history — the 17th-century barque Griffon — is believed to be lying in a tomb of sand awaiting conclusive identification. The first sailing ship on the Great Lakes, the Griffon was built in 1679 near present-day Niagara Falls, Ont., by the famed French explorer Rene-Robert Cavelier, Sieur de La Salle, and symbolized the ambitions of New France to construct and control...