192 



rivers, the Machangara, the Rio del Matadero> 

 and the Yanuncai ; of which the two former 

 are white, and the waters of the last are black 

 (aguas negras). These waters, like those of 

 the Atabapo, are of a coffee colour by reflec- 

 tion, and pale yellow by transmission. They 

 are very fine, and the inhabitants of Cuenca ? 

 who drink them in preference, do not fail to 

 attribute their colour to the sarsaparilla, which 

 it is said grows abundantly on the banks of the 

 Rio Yanuncai # . 



April 23d. We left the mouth of the Zama 

 at five in the morning. The river continued 

 to be skirted on both sides by a thick forest. 

 The mountains on the east seemed to retire by 

 degrees farther back. We passed first the 

 mouth of the Rio Mataveni, and afterward an 

 islet of a very singular form ; a square granitic 

 rock, that rises like a trunk in the middle of 

 the *water. It is called by the missionaries 

 El CastillHo. Black bands seem to indicate, 

 that the highest swellings of the Oroonoko do 

 not rise at this place above eight feet ; and 

 that the great swellings observed lower clown 

 are owing to the tributary streams, which 



* Although the species of smilax abound principally in hot 

 and temperate regions (from 0 to 600 toises), we have how- 

 ever found them between 700 and 1400 toises. See our 

 Nov, Gen. Plant., vol. I, p. 72. 



