78 Charles Darwin. 



observant of their flight, and in a letter, written to 

 the late Dr. J. B. Holder, expressed his astonish- 

 ment that these birds could circle about, moving up 

 and down, covering great distances without appar- 

 ently vibrating the wings. 



While the condors live upon carrion, they often 

 attack young animals; hence the natives trained 

 their dogs to dash out and bark as they approached. 



The Indians caught them in an ingenious way: 

 they surrounded a dead animal with a fence of sharp 

 sticks, and when the condor became gorged with 

 food, rushed in on horseback and shut the enclosure 

 before the bird could escape. Another method wit- 

 nessed by Darwin consisted in creeping up to where 

 the birds roosted and dropping a noose over their 

 heads while they were asleep. 



In March, 1833, the party arrived at East Falk- 

 land Island, in Berkeley Sound, where wild-cattle 

 hunting formed one of the exciting incidents. Many 

 hard and fatiguing rides were taken, on one of which 

 Darwin states that his horse fell no less than six 

 times, and frequently all the animals ridden by the 

 party were floundering in the mud. In Berkeley 

 Sound Darwin found a curious geological feature, 

 nothing less than a river of stones, the valley being 

 made up of rocks thrown together in the wildest 

 manner possible and apparently flowing down to the 

 sea. The width of the stream varied from a few 

 hundred feet to a mile, and was of unknown depth, 

 water being distinctly heard trickling far below the 

 surface. In one valley south of Berkeley Sound one 

 of these stone rivers was seen, where for a quarter 



