Melville Island, 42 149 km2, is the fourth-largest of the QUEEN ELIZABETH ISLANDS. The Northwest Territories-Nunavut boundary splits the island in half. Its western half, which is in the Northwest Territories, is hilly, with elevations reaching 776 m, and sustains small ice fields. The eastern half, which is part of Nunavut, is a rolling plateau with elevations generally below 300 m. Vegetation is scant, but well-vegetated broad valleys and coastal flatlands support a relatively high muskoxen population. Caribou numbers are low, owing to recent adverse climatic events. The island was discovered in 1819 by Sir William PARRY, who named it after Viscount Melville, first lord of the Admiralty. Promising natural-gas and oil deposits have been found on and around the island.