and also on the Lower Amazon the difference of water level between wet and dry seasons is at least fifty feet, and most of the affluents rise and fall proportionately.
The great Brazilian plateau, which has just been mentioned, further justifies the description of South America as the fertile continent--the region of habitable tropics. The vast scale of this plateau and its relation to the River Plate system justify its description here as a continental feature rather than a purely national feature, although it is mainly a national possession of Brazil. From the north-east shoulder of the Brazilian coast, this varied plateau, seamed by many clefts, stretches southwards and south-westward in a vast semi-circular sweep dividing the two river-systems. The Paraná and its affluents plunge from this plateau towards the south and west. Northwards and eastwards it sends a multitude of streams to the Amazon and the Atlantic. These Brazilian uplands naturally vary in character and productiveness, but the