344 NORTHERN CHILE. [CHAP. xVI. 



gunpowder? Mr. Gill also mentioned to me a most interesting, 

 and, as far as I am aware, quite unparalleled case, of a subterranean 

 disturbance having changed the drainage of a country. Travelling 

 from Casma to Huaraz (not very far distant from Lima), he found 

 a plain covered with ruins and marks of ancient cultivation, but 

 now quite barren. Near it was the dry course of a considerable 

 river, whence the water for irrigation had formerly been conducted. 

 There was nothing in the appearance of the water-course, to 

 indicate that the river had not flowed there a few years previously ; 

 in some parts, beds of sand and gravel were spread out ; in others, 

 the solid rock had been worn into a broad channel, which in one 

 spot was about 40 yards in breadth and 8 feet deep. It is self- 

 evident that a person following up the course of a stream, will 

 always ascend at a greater or less inclination : Mr. Gill, therefore, 

 was much astonished, when walking up the bed of this ancient 

 river, to find himself suddenly going down hill. He imagined that 

 the downward slope had a fall of about 40 or 50 feet perpendicular. 

 We here have unequivocal evidence that a ridge had been uplifted 

 right across the old bed of a stream. From the moment the river- 

 course was thus arched, the water must necessarily have been 

 thrown back, and a new channel formed. From that moment, also, 

 the neighbouring plain must have lost its fertilizing stream, and 

 become a desert. 



June 27th. We set out early in the morning, and by midday 

 reached the ravine of Paypote, where there is a tiny rill of water, 

 with a little vegetation, and even a few algarroba trees, a kind of 

 mimosa. From having fire-wood, a smelting-furnace had for- 

 merly been built here : we found a solitary man in charge of it, 

 whose sole employment was hunting guanacos. At night it froze 

 sharply ; but having plenty of wood for our fire, we kept ourselves 

 warm. 



28<A. We continued gradually ascending, and the valley now 

 changed into a ravine. During the day we saw several guanacos, 

 and the track of the closely-allied species, the Vicuna : this latter 

 animal is pre-eminently alpine in its habits ; it seldom descends 

 much below the limit of perpetual snow, and therefore haunts even 

 a more lofty and sterile situation than the guanaco. The only 

 other animal which we saw in any number was a small fox : I 

 suppose this animal preys on the mice and other small rodents, 



