QUINTANA ROO, MEXICO—BBC News reports that an eight-foot cannon, anchor, and pig-iron ingots thought to have been used as a ship’s ballast were spotted by a fisherman in the Caribbean Sea off the coast of southern Mexico. The wreckage rests in shallow waters and rough ocean currents at the Banco Chinchorro atoll reef, a dangerous area where 70 historic shipwrecks have been registered. Archaeologists from Mexico’s National Institute of Anthropology and History said the vessel could be the remains of an English sailing ship built in the late eighteenth or early nineteenth century. Its crew may have tried to prevent the ship from sinking by attaching its anchor to the coral reef, where it is now embedded. The ship has been named the Manuel Polanco, after the fisherman who discovered it and several other shipwrecks in the area. To read about a wreck that may be the remains of the last ship to transport enslaved Africans to the United States, go to "The Case for Clotilda."