NIGERIA 189 



there, galleries of evergreen vegetation occupying the intersecting 

 belts of permanent streams or fringing a marsh, wide meadows bordered 

 b}' low forest, but occupied entirely by grasses of few species, with 

 scattered islets of foliage, or, again, outcrops of bare laterite and 

 isolated domes and turtle-backs of crystalline rock, " inselbergs " and 

 " kopjes," introducing features of their own. 



The Niger Delta displays admirably the high evergreen or moist 

 tropical forest. This probably connects itself through the Kameruns with 

 the great Central African forest of French and Belgian Congo, which 

 is again said to be continuous through the gap between Ruwenzori 

 and Lake Albert with that of British East Africa. 



West of the Niger Delta the coast, including Lagos, Dahomey 

 and Togo, is sandy, and bush rather than high forest commences almost 

 on the shore. Ascending the Niger, one finds that the true " rain 

 forest " ends, but not abruptly, in the neighbourhood of Asaba ; a 

 gradual transition occurs, first to an intermediate type, partly ever- 

 green with many large trees, but mingled with those that lose their 

 leaves in the months of little rainfall. This change is apparent even 

 on the river-bank, and below Lokoja a more open but still semi- 

 evergreen forest clothes the valleys, but shows already more of the 

 deciduous element on the hills. Farther north the voyage from the 

 mouth of the Kaduna River to the Zungeru light railway terminus 

 at Barijuko, as often experienced in previous years, reveals again 

 the progressively deciduous character of the foliage, resulting in a 

 still more open forest. 



The river-bank, however, possessing permanent moisture and 

 its own local climate, is an inadequate index of the general features 

 over the countr}^ at large. To travel bj^ land from Baro to Zungeru, 

 and thence either through Kontagora to Sokoto, or by Zaria to Kano 

 and Gummel, is to have the complete vision of the West African 

 savannah in its various degrees, and, except for local interruptions 

 associated with considerations of altitude or geological outcrop, etc., 

 or with the lines of perennial streams, to have it in its regular sequence. 



Leaving out of account for the present the region south of Lokoja 

 and of the south bank of the Benue, which in part represents the 

 " Zone Guineenne " of Chevalier, we find that the two routes suggested 

 above will take one through country almost entirely of the types 

 included by the same writer within the " Zone Soudanienne," with 

 an approach at places along the Anglo-French boundary to the con- 

 ditions occurring in his " Zone Sahelienne," It would be difficult 

 and misleading to express these zones definitely in terms of latitude, 

 but one might hazard the statement that the Guinea Zone passes to 

 the Soudan Zone somewhere betAveen 8° and 10° North, and the latter 

 extends either to the northern boundarj^ or verges on a drier belt 

 beyond the latitude of 12° or 13° North. If a complete botanical 



