188 VOYAGE DOWN THE RIO NEGEO. 



stream, assisting the upward-bound voyager, but often 

 driving back upon its course, in spite of paddles, the de- 

 scending canoe. 



Upon tlie morning of the last day of the year, we 

 passed Carvoeiro, and two hours later lauded for breakfast 

 iTpon some granitic rocks, the first of any kind that had 

 appeared below San Isabel. Not far below this point the 

 Rio Branco, the largest tributary of the Rio Negro, pours 

 in its white waters from the north. This river abounds in 

 the great tortuga and other species of tortoises, which, 

 during the season when they resort to the playa to deposit 

 their eggs, draw thither the inhabitants of the Rio Negro, 

 and the settlements that exist upon its own banks, for the 

 purpose of supplying themselves with food against the 

 long dearth of the rainy period. For three hundred miles 

 from its mouth, the Rio Branco is said to be unbroken 

 with rapids, and the country through which it flows, 

 densely wooded.* Above this, obstructions prevent its 

 navigation, excepting with light canoes, and open savannas 

 spi'ead out from its banks, aftbrding pasturage to herds of 

 wild cattle from which the inhabitants of Manaos obtain 

 their supply of beef. A portage of a couple of hours con- 

 nects the head-waters of the river with those of the 

 Essequibo. f 



Late in the afternoon, and several hours below the Rio 

 Branco, we reached Pedrero (sometimes written Pedrei- 

 ro), a village of twenty houses, the highest point reached 

 by x\gassiz in his excursion on the " Ibicuhy " up the Rio 



* Upon the banks of tins river is found the remarkable mavaponima, 

 " tortoisc-sliell wood," a most beautiful wood much employed in the arts. 



f Upon the Putaro, a tributary of the Essequibo River, there has re- 

 cently been discovered (April, ISTO), by Mr. C. B. Brown, of the Geo- 

 logical Survey of British Guiana, a fall of over eight hundred feet in 

 height, which is said to have but few rivals in picturesqueness and gran- 

 deur. 



