288 LINES OF MOUNTAIN RIDGES. 



dilleras being altogether in disuse as applied to the chains 

 of mountains extending from the eastern gulf of Maracaibo 

 to the promontory of Paria, we shall continue to designate 

 those chains (stretching from west to east) by the names of 

 "littoral chain," or " coast-chain of Venezuela." 



Of the three insulated groups of mountains, that is to 

 eay, those which are not branches of the Cordillera of the 

 Andes and its continuation towards the shore of Venezuela, 

 one is on the north, and the other two on the west of the 

 Andes : that on the north is the Sierra Nevada de Santa 

 Marta ; the two others are the Sierra de la Parime, between 

 4 and 8 of north latitude, and the mountains of Brazil, 

 between 15 and 28 south latitude. This singular distri- 

 bution of great inequalities of soil produces tkree plains 

 or basins, comprising a surface of 420,600 square leagues, or 

 four-fifths of all South America, east of the Andes. Between 

 the coast-chain of Venezuela and the group of the Parime, 

 the plains of the Apure and the Lower Orinoco extend ; 

 between the group of Parime and the Brazil mountains are 

 the plains of the Amazon, of the Bio Negro, and the Madeira, 

 and between the groups of Brazil and the southern extremity 

 of the continent are the plains of Bio de la Plata, and of 

 Patagonia. As the group of the Parime in Spanish G-uiana, 

 and of the Brazil mountains (or of Minas Greraes and Groyaz), 

 do not join the Cordillera of the Andes of New Grenada and 

 Upper Peru towards the west, the three plains of the Lower 

 Orinoco, the Amazon, and the Bio de la Plata, are connected 

 by land-straits of considerable breadth. These straits are 

 also plains stretching from north to south, and traversed 

 by ridges imperceptible to the eye, but forming " divortia 

 aquarum." These ridges (and this remarkable phenomenon 

 has hitherto escaped the attention of geologists) are situ- 

 ated between 2 and 3 north latitude, and 16 and 18 

 south latitude. The first ridge forms the partition of the 

 waters which fall into the Lower Orinoco on the north-east, 

 and into the Bio Negro and the Amazon on the south and 

 south-east ; the second ridge divides the tributary streams 

 of the right bank of the Amazon and the Bio de la Plata. 

 These ridges, of which the existence is only manifested, as 

 in Volhynia, by the course of the waters, are parallel with 

 the coast-chain of Venezuela ; they present, as it were, two 



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