Gabon, Relief and drainage

The narrow coastal plain—often no more than 20 miles (32 kilometres) wide in the south—is formed of sandstone and alluvium; northward it broadens to a width of 100 miles, with outcrops of chalk, limestone, and Cretaceous sandstone. North of the most westerly point, Cape Lopez, the contour of the coast becomes more jagged. The Atlantic's northward-flowing Benguela Current, which