wonderful that men should have attempted such operations, without the
use of iron or 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 firewood, a smelting-furnace had formerly 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.
28th.--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, which, as long as there is the least
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