rising at the foot of the Cordillera. With respect to its source, I do
not doubt that this is the case for the Gauchos assured me, that in the
middle of the dry summer, this stream, at the same time with the
Colorado has periodical floods; which can only originate in the snow
melting on the Andes. It is extremely improbable that a stream so
small as the Sauce then was, should traverse the entire width of the
continent; and indeed, if it were the residue of a large river, its
waters, as in other ascertained cases, would be saline. During the
winter we must look to the springs round the Sierra Ventana as the
source of its pure and limpid stream. I suspect the plains of
Patagonia like those of Australia, are traversed by many water-courses
which only perform their proper parts at certain periods. Probably this
is the case with the water which flows into the head of Port Desire,
and likewise with the Rio Chupat, on the banks of which masses of
highly cellular scoriae were found by the officers employed in the
survey.
As it was early in the afternoon when we arrived, we took fresh horses,
and a soldier for a guide, and started for the Sierra de la Ventana.
This mountain is visible from the anchorage at Bahia Blanca; and Capt.
Fitz Roy calculates its height to be 3340 feet--an altitude very
remarkable on this eastern side of the continent. I am not aware that
any foreigner, previous to my visit, had ascended this mountain; and
indeed very few of the soldiers at Bahia Blanca knew anything about it.
Hence we heard of beds of coal, of gold and silver, of caves, and of
forests, all of which inflamed my curiosity, only to disappoint it. The
distance from the posta was about six leagues over a level plain of the
same character as before. The ride was, however, interesting, as the
mountain began to show its true form. When we reached the foot of the
main ridge, we had much difficulty in finding any water, and we thought
we should have been obliged to have passed the night without any. At
last we discovered some by looking close to the mountain, for at the
distance even of a few hundred yards the streamlets were buried and
entirely lost in the friable calcareous stone and loose detritus. I do
not think Nature ever made a more solitary, desolate pile of rock;--it
well deserves its name of _Hurtado_, or separated. The mountain is
steep, extremely rugged, and broken, and so entirely destitute of
trees, and even bushes, that we actually could not make a skewer to
stretch out our meat over the fire of thistle-stalks. [1] The strange
aspect of this mountain is contrasted by the sea-like plain, which not
102