OBIGIS Or THE AMAZON. 251 



The first, the Atures, is most easily passable when the 

 waters are low. The Indians prefer crossing the second, 

 the Maypures, at the time of great floods. Beyond the 

 Maypures and the mouth of the Cano Cameji, the Orinoco 

 is again unobstructed for the length of more than one 

 hundred and sixty-seven leagues, or nearly to its source; 

 that is to say, as far as the Baudalito of Guaharibos, east of 

 the Cano Chiguire and the lofty mountains of Yurnariquin. 



Having visited the basins of the two rivers Orinoco and 

 Amazon, I was singularly struck by the differences they 

 display in their course of unequal extent. The falls of the 

 Amazon, which is nearly nine hundred and eighty nautical 

 leagues (twenty to a degree) in length, aro pretty near its 

 source in the first sixth of its total length, and five-sixths 

 of its course are entirely free. "We find the great falls of 

 the Orinoco on a point far more unfavourable to navigation ; 

 if not at the half, at least much beyond the first third of its 

 length. In both rivers it is neither the mountains, nor the 

 different stages of flat lands lying over one another, whence 

 they take their origin, that cause the cataracts ; they are 

 produced by other mountains, other ledges which, after a 

 long and tranquil course, the rivers have to pass over, 

 precipitating themselves from step to step. 



The Amazon does not pierce its way through the prin- 

 cipal chain of the Andes, as was affirmed at a period when 

 it was gratuitously supposed that, wherever mountains are 

 divided into parallel chains, the intermedial or central ridge 

 must be more elevated than the others. This great river 

 rises (and this is a point of some importance to geology) 

 eastward of the western chain, which alone in this latitude 

 merits the denomination of the high chain of the Andes. 

 It is formed by the junction of the river Aguamiros with 

 the Bio Chavinillo, which issues from the lake Llauricocha 

 in a longitudinal valley bounded by the western and the 

 intermedial chain of the Andes. To form an accurate idea 

 of these hydrographical relations, it must be borne in mind 

 that a division into three chains takes place in the colossal 

 group or knot of the mountains of Pasco and Huanuco. 

 The western chain, which is the loftiest, and takes the name 

 of the Cordillera Real de Nieve, directs its course (between 

 lluary and Caxatamba, Guamachuco and Luc-ma, Micui- 



