From the apex of the Niger Delta Southwards, dry land, overgrown with dense forest still virginal in various spots, gives way to seasonally inundated zones. Here, sweet water swamps with stands of raffia palms gradually merge into tidal swamps of brackish ooze, where mud skippers thrive under the arching roots of mangrove. The Niger, fingering through a thousand creeks, meets the sea in a dozen estuaries. Strong river current drifts and mud across the river mouths, sealing them again and again to navigation.