one of the Galápagos Islands, in the eastern Pacific Ocean, about 600 miles (965 km) west of Ecuador. It has an area of about 7 square miles (18 square km) and is flanked on the west by five small islets known as Guy Fawkes Island. The island's relief is made up of cactus-studded littoral and several volcanic craters, the highest rising to 1,300 feet (400 m). Originally named for Sir Anthony Dean (Deane), an English shipbuilder, the name was changed in the 18th century to honour the English admiral Viscount Duncan. The official Ecuadorian name is Isla Pinzón. It has a large marine tortoise reserve, as well as a seal rookery, but no human population.