Bay of Fundy is an extension of the North Atlantic Ocean that divides New Brunswick from western Nova Scotia. The bay is about 60 miles (100 kilometers) wide at its mouth. It reaches inland about 150 miles (240 kilometers), where it separates into Chignecto Bay and Minas Basin. The upper part of the bay is famous for its tides, which are among the highest in the world. These tides rise and fall over a range that is sometimes greater than 50 feet (15 meters). Such massive water movement, combined with accumulation of sediment through erosion, has built up large salt marshes that serve as a feeding station for migrating shore birds. The lower Fundy also is a feeding ground for marine life, including whales.