The Heights of Guan, a variant of "Gowanus", was the New York colonial era name given to a series of hills which extend in a ridge along the western portion of Long Island. The ridge extends in an east northeast direction starting from Bay Ridge, Brooklyn with hills of varying heights of 100 to 150 feet (30-45m), with the southern slope of the ridge having a relatively steep drop and the rear, a more gradual slope. The ridge marks the terminal moraine of the Wisconsin Glacier that formed the North Shore of Long Island, south of the ridge is the outwash plain bordered by the Atlantic Ocean.