60 FROM MENDOZA TO SANTIAGO AND BACK 



Greatly to my surprise, there was very little snow on the road, and that was lying in patches ; 

 the greater part of the mountain near heing as dry as a desert. 



After making a barometrical measiirement for the elevation, we started down, and very soon 

 found the road so bad that we had to dismount and descend on foot. Properly speaking there 

 is no road, but the mere semblance of a mule-path, winding by zigzags down a spur whose 

 surface is covered with loose stones which roll from underfoot to its base, threatening at times 

 to end in a general avalanche of mules^ men, and stones. 



After about a league of zigzagging, we arrived at a little arroyo at the base of the steepest 

 part, where we stopped to drink and rest. We again mounted here; proceeded two miles 

 along the south side of this streamlet ; then crossed the head-waters of the Rio del Yeso, 

 which comes from the northeastward ; and, a mile farther on, after crossing a spur from the 

 northward, we entered the valley of the Yeso. The ax^pearance of the valley hereabouts is very 

 singular. It is covered with rocks of many kinds, decomposed and decomposing, and presents 

 the ajjpearauce of an immense bed of half-slacked lime — not so much from the color of the rocks, 

 although white predominates, as from their crumbling condition. Large masses of pudding- 

 stone are to be seen, so far decomposed as to require only a slight blow to split them in pieces. 



The account given of this singular place by the inhabitants of San Jose is^ that some years 

 ago, while the mountain-passes were closed by the winter's snow, a shock was felt like that of 

 an earthquake, accompanied by a great noise from this direction ; and on the opening of the 

 spring the muleteers found the road blocked up. 



The appearance of the surrounding hills does not warrant the belief that it was a land-slide ; 

 and unless due to volcanic eruption, it is difficult to conceive how such a state of things could 

 have been produced. 



Besides these decomposed rocks, the flats near the stream are covered with a white efflores- 

 cence resembling soda. 



Two or three miles in a direction north of west over this kind of ground^ brought us to a 

 gorge on our right from which a streamlet issues. We here turned to the southwestward, and 

 travelled about nine miles down a flat valley covered with vegetation, to a barrier range running 

 from the high mountains on the north nearly across to those on the south, only separated from 

 the latter by the Yeso, which, with the waters of its tributaries, passes between it and the foot 

 of a high and rugged mountain, which I believe is the extinct volcano of Jan Jose. The road 

 generally leads between the Yeso and the streamlet to the northward, but crosses to the south 

 side of the former in front of a hill called the Cerro del Yeso, from which the stream takes its 

 name. We saw a party of men there loading mules with yeso (gypsum) for the Chilean market. 



Fording this stream was rather a formidable business. It was about eight yards wide and 

 three feet deep, with a rajiid current, and the loose and rounded stones of its bed made it very 

 difficult for the mules to keep their footing. 



On the north side, and about half way down the valley, there is a steep hill, with quite a 

 plane front, crossed by several dikes nearly at right angles with each other, which give it the 

 appearance of a field divided into small, irregular lots. In the corner formed by the barrier 

 hill and the northern range there is a small laguna, around which were a great number of 

 birds, principally waders, about the size of curlews, but with wings of a dark color, and white 

 bodies. They are called piuquens. 



About three miles (including turns) over the barrier hill, and one more across a small valley, 

 brought us to the banks of a stream issuing from a deep ravine to the northward, where we 

 camped for the night. 



I regret that I did not measure the height of this barrier. It must be near a thousand feet 

 above the valley, and in crossing appears to be almost interminable. The road is tolerably 

 good, but there is a dangerous-looking ladera on it — the valley, on the one hand, being several 

 hundred feet below, and the hill-side, on the other, uncomfortably studded with large boulders, 

 which appear to be on the point of tumbling down. I could not help feeling nervous when I 



