Great inlet of the Atlantic Ocean, western Central African coast.
It includes the Bights of Benin and Biafra , and its major tributaries are the Casamance , Volta , and Niger rivers. Its natural resources include offshore oil deposits and metal ore deposits. Its coastline forms part of the western edge of the African tectonic plate and corresponds remarkably to the continental margin of South America from Brazil to the Guianas, providing one of the clearest confirmations of the theory of continental drift .