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 de Nolasko. In 
the first place, metallic veins in this country are generally 
harder than the surrounding strata ; hence, during the gradual 
