INTRODUCTION, 



the Pacific, and is in fact a continuation of the rocky 

 mountains of North America. The second is the 

 chain, which branches from the Cordillera in the pro- 

 vince of Quito, passes through New Grenada towards 

 the Atlantic, and pursuing a course nearly parallel, is 

 interrupted by the Orinoko, reappears in Guyana, 

 and approaches the Amazon, when it is in like man- 

 ner broken by the immense valley of this river. It 

 afterwards shews itself in Brazil, traversing it in the 

 whole extent, again subsiding in the highlands of 

 Maldonado near La Plata. The third chain, called 

 the Eastern Cordillera of Peru, runs towards the tro- 

 pic, whence it takes an inclined direction, and termi- 

 nates in the south east, in the plains of the Grand 

 Chaco. There is another chain, which runs close 

 along the coast of Brazil, and forms the great valley of 

 the river St. Fran( is. There are besides a number of 

 interior chains, particularly those which separate the 

 valleys of the great rivers of Brazil. From tlje east- 

 ern ridges, there is a gradual slope to the interior, 

 while on the coast their ascent is abrupt and steep. 

 Their elevation is considerably less than the Codille- 

 ra or Andes, and they are more irregular and |}roken. 

 The vast tract of country which stretches along the 

 heads of the Amazon and La Plata, upwards of three 

 thousand miles in length, and probably more than 

 three hundred in breadth, is one of the most rugged 

 and mountainous on the globe; it is a continued suc- 

 cession of deep vallies, of various dimensions, enclos- 

 ed by mountains whose summits in general, are cover- 

 ed with perpetual snows. In the northern part, there 

 are plains of such elevation as to aflPord all the advanta- 

 ges of the most temperate and delightful climates; to the 



