XV TORRENTS OF THE CORDILLERA 339 



stones, as they rattled one over another, was most distinctly 

 audible even from a distance. This rattling noise, night and day, 

 may be heard along the whole course of the torrent. The sound 

 spoke eloquently to the geologist ; the thousands and thousands 

 of stones which, striking against each other, made the one dull 

 uniform sound, were all hurrying in one direction. It was like 

 thinking on time, where the minute that now glides past is 

 irrecoverable. So was it with these stones ; the ocean is their 

 eternity, and each note of that wild music told of one more step 

 towards their destiny. 



It is not possible for the mind to comprehend, except by a 

 slow process, any effect which is produced by a cause repeated 

 so often that the multiplier itself conveys an idea not more 

 definite than the savage implies when he points to the hairs of 

 his head. As often as I have seen beds of mud, sand, and 

 shingle, accumulated to the thickness of many thousand feet, I 

 have felt inclined to exclaim that causes, such as the present 

 rivers and the present beaches, could never have ground down 

 and produced such masses. But, on the other hand, when 

 listening to the rattling noise of these torrents, and calling to 

 mind that whole races of animals have passed away from 

 the face of the earth, and that during this whole period, 

 night and day, these stones have gone rattling onwards in their 

 course, I have thought to myself, Can any mountains, any 

 continent, withstand such waste ? 



In this part of the valley, the mountains on each side were 

 from 3000 to 6000 or 8000 feet high, with rounded outlines 

 and steep bare flanks. The general colour of the rock was 

 dullish purple, and the stratification very distinct. If the 

 scenery was not beautiful, it was remarkable and grand. We 

 met during the day several herds of cattle, which men were 

 driving down from the higher valleys in the Cordillera. This 

 sign of the approaching winter hurried our steps, more than was 

 convenient for geologising. The house where we slept was 

 situated at the foot of a mountain, on the summit of which are 

 the mines of S. Pedro de Nolasko. Sir F. Head marvels how 

 mines have been discovered in such extraordinary situations as 

 the bleak summit of the mountain of S. Pedro dc Nolasko. In 

 the first place, metallic veins in this country are generally 

 harder than the surrounding strata ; hence, during the gradual 



