A recently computed fit of the African and South American continents is astonishingly close, apart from an overlap of some 120 miles in the vicinity of the Niger delta. This paper attempts to determine whether there is a genuine misfit at this point or whether the delta may have grown beyond the continental margin after the continents separated. The evidence suggests that final separation took place in Albian times, and that the bulge of the present continental edge into the Atlantic Ocean has resulted from post-Cretaceous development of the delta. The gross structure of the delta region and also the associated minor structures are considered to represent a passive response to the influx of sediment from the Niger river.