Martinique is located around 14°30' of north latitude and 61° of west longitude in the heart of the Lesser Antilles arc that separates the Caribbean Sea from the Atlantic Ocean. It was named by Christopher Columbus, who landed there on his fourth expedition in 1502 on Saint Martin's Day. Its area of ​​700 square miles (1,128 km²), the size of a small French department, is 90 % covered by volcanic deposits that leave only 10 % of the territory to limestone sediments and quaternary formations. Martinique's turbulent geological history results from its particular position at the convergence between two West Indian arcs that diverge to the north: one towards Anguilla via Grande-Terre de Guadeloupe, Saint-Barthélemy, and Saint-Martin; the other to Saba via Basse-Terre de Guadeloupe. It is responsible for its varied reliefs: high in the young northwestern part of the island visible here, where they culminate at Mount Pelée (4,583 ft / 1,397 m), but barely exceeding 1,640 ft (500 m) in the south, at the Vauclin mountain.