84 NATURAL HISTORY OF 



deluge, which, it seems, was confounded with a similar 

 event, already recorded among the devastations of 

 Greece. In the plains of Morocco, among the high 

 lands of Abyssinia, in the bed of the Quorra (Niger) 

 in Congo, and at the Cape of Good Hope, similarly 

 formed table mountains, with precipitous sides and 

 limestone summits occur, and with deep valleys or flats 

 between them, produced by forces that cannot, now 

 be satisfactorily explained. We may add, that while 

 all the ancient adventitious populations have greati.y 

 decreased, the indigenous negro races alone continue to 

 expand. 



