94 



AMAZONIA AND LA PLATA. 



It has its source in the upland valleys of the Colombian Andes south of the 

 Guaviare or Western Orinoco ; its course follows the same direction as the main 

 stream between San Joaquim and Barcellos ; the beds of both rivers also present 

 the same geological characters, while both descend to the lower reaches through a 

 series of granite falls and rapids. Above the Jurupari, highest of these falls, the 

 river, here as " white " as the Solimoes and inhabited by the same species of fishes, 

 traverses the level, treeless plains at the foot of the Andes. The Uaupes was 

 ascended to its source by Jesuino Cordeiro in 1854, and since then its lower reaches 

 have been visited by Wallace, Stradelli, and Coudreau, all of whom assert that its 

 mean discharge greatly exceeds that of the Upper Rio Negro. During the floods 



Fjo-. 31. IJAtrPES Confluence and Rio Negeo CATAEAcrs 



Scale 1 : 1,500,000. 











iao Pedro . 



• V-..°.s'-'.' °'o.- : ^il^^M^iX'-'i- '■'■: ■^ ■ -'.a:-"' 



West or breenwich 



67° 



30 Miles. 



one of its affluents communicates through the Ira Parana with the Apapuris tribu- 

 tary of the Japura. 



Above the Uaupes confluence the Rio Negro is connected by the Cassiquiare 

 with the Orinoco system. Another less known and less important bifurcation 

 occurs farther south, where the Baria ramifies into two branches, one of which 

 flows north to the lower Cassiquiare, while the other descends directly to the Rio 

 Negro under the name of Rio Canabury. A continuous waterway almost parallel 

 with the Upper Rio Negro is thus developed in the direction of the east for a 

 distance of about 300 miles, without, however, offering any advantage to the 

 navigation by canoes at the divide. 



Below the Cassiquiare confluence the Rio Negro enters Brazilian territory at 



