230 PORTILLO PASS. [CHAP. XT. 



the gradual elevation of the Cordillera, by the torrents delivering, at 

 successive levels, their detritus on the beach-heads of long narrow 

 arms of the sea, first high up the valleys, then lower and lower down 

 as the land slowly rose. If this be so, and I cannot doubt it, the grand 

 and broken chain of the Cordillera, instead of having been suddenly 

 thrown up, as was till lately the universal, and still is the common 

 opinion of geologists, has been slowly upheaved in mass, in the same 

 gradual manner as the coasts of the Atlantic and Pacific have risen 

 within the recent period. A multitude of facts in the structure of 

 the Cordillera, on this view receive a simple explanation. 



The rivers which flow in these valleys ought rather to be called 

 mountain-torrents. Their inclination is very great, and their water 

 the colour of mud. The roar which the Maypu made, as it rushed 

 over the great rounded fragments, was like that of the sea. Amidst 

 the din of rushing waters, the noise from the 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 stone, 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 

 3,000 to 6,000 or 8,000 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 

 San Pedro de Nolasko. Sir F. Head marvels how mines have been 

 discovered in such extraordinary situations, as the bleak summit of 

 the mountain of San Pedro de Nolasko. In the first place, metallic veins 



