On the morning of the 29th, our course (S. 35° E.) brought us at the distance of three miles from our camp, to the foot of the cliff which separates the valley from the high plain. This mural barrier has an elevation of about two hundred feet, and is impassable, except at particular points, where it is broken by ravines. One of these we were fortunate in finding, without being compelled to deviate greatly from our course, and climbing its rugged declivity, we emerged upon the broad expanse of the high plain. Turning with a sort of involuntary motion towards the west, we again caught a view of the distant summits of the Andes appearing on the verge of our horizon. The scene before us was beautifully varied with smooth valleys, high conic hills, and irregular knobs, scattered in every direction as far as the eye could comprehend. Among these singular eminences nothing could be perceived like a continuous unbroken range. Most of them stand entirely isolated; others in groups and ranges, but all are distinct hills, with unconnected bases. The surface of the country generally, and more especially in the immediate vicinity of these hills, is strewed with fragments of compact or porphyritic greenstone. These are, in some places, accumulated in such quantities as render the passing extremely difficult. At half-past eleven, A. M., a violent storm, with high and cold wind, came on from the north-east, and continued for two hours. Soon after its commencement we halted to dine, but were unable to find a spot affording wood until so much rain had fallen as to wet our clothing and baggage. Fire was almost the only comfort we could now command, our {271} provisions being so nearly exhausted, that about an ounce of jerked bison meat was all that could be allowed each man for his dinner.