DESCRIPTIVE GEOGRAPHY. 7 



From the sum m it of the Piuquenes there is a descent of about 3,000 feet to A valley fifteen 



miles in extent, \\\\\x 1'H \veeu it and the Portillo range, the latter having itg origin at Tupun- 

 ;m<l e\t( iiilinv; into the Argentine territory in a south hy west direction. 'The river 

 Tiinnyan has its source near the head of this basin, and flows nearly through its centre. As 

 n.. animals arc sullirient 1 y I'rcsli to attempt ems.;,,^ both summits and the plain in one day, it 

 is necessary to pass anight here; and this is the locality where most danger is to be appre- 

 hended from snow-storms. They are accompanied with violent thunder and lightning, rendered 

 more terrific by the rarity of the atmosphere and deafening echoes of the surrounding rocks. 

 Except during the winter months, they rarely occur by day ; and it is only when the sun has 

 gone, and the wind has ceased at night, that the arriero apprehends accumulating clouds ; even 

 then, until the thunder startles him, he sleeps tranquilly. Should a storm occur, unless the 

 animals have been sufficiently rested to recommence their journey, (as there is scarcely any 

 place of refuge,) the danger of burial alive is imminent. Nor does it terminate here; so intri- 

 cate is the path, that there is scarcely less risk of wandering astray in the darkness, and of 

 falling into one of the mighty chasms, or into no less perilous snow-banks, from whose depths 

 none ever escape. As these great beds evaporate and thaw under the more moderate tempera- 

 ture and drying winds of summer, they leave solid columns and pinnacles of ice, many of them 

 so closely resembling draped human figures, immovable in the desolation, that they have been 

 called "Los Penitentes" (the penitents). Colossal as they are, in comparison with the bare 

 and barren cones of granite around, they are as pigmies; and in this region, where every object 

 is so unlike all previous experience, it would require little effort of imagination to regard them 

 as monuments of Divine wrath, like Lot's wife, punished for crime. When Dr. Darwin crossed 

 in March, 1835 a frozen horse stood on one of these ice-columns as on a pedestal, its hind legs 

 in the air. No doubt it had fallen headlong when the snow around that spot was nearly level, 

 and had been left in this position by subsequent evaporation. In summer, when the basin is 

 covered with pasturage, cattle are sometimes driven from the Chile side, where it becomes 

 exhausted much earlier; and herds of guanacos are occasionally seen browsing along its borders, 

 the condor, from his pinnacled eyrie or circling flight, impatiently watching for the feasts these 

 visits seldom fail to afford him. 



The ascent to the Portillo from the valley of the Tunuyan is even more toilsome and wearying 

 than that up the Piuquenes ridge. The narrow path lies amid immense conical hills of reddish 

 granite, overlaid by quartz and conglomerates of pebbles and shells, sometimes within a foot of 

 vertical precipices, and at others beneath overhanging masses of rock, apparently ready to 

 tumble from their balance under the slightest effort. Here Tupungato, with its glacier peak, 

 first comes in sight ; and when, after climbing 14,475 feet (measurement of Lieut. MacRae) 

 above the ocean, the Portillo itself is reached, the ocean-like pampas of Buenos Ayres may 

 be overlooked through its contracted aperture. From this narrow cleft or door in the ridge, 

 just wide enough for a loaded mule to pass, comes the name "portitto" a little door. 



Prof. Domeyko is the only scientific traveller known to me who has penetrated to the crest of 

 the Andes by any other of the passes. A geological account of his journey to "Come Cavallo" 

 (literally eat horse) pass, in the province of Atacama, and "Laguna" (lake} pass, in the 

 province of Coquimbo, may be found in the Annales des Mines, vol. ix, 1846. These journeys, 

 and others, to different elevations in the Andean chain, south of Santiago-, made subsequently, 

 were frequent subjects of conversation ; and the information respecting them has been wholly 

 obtained from him. 



COME CAVALLO Pass. Leaving the city of Copiapo, the road leads up the valley of the river of 

 the same name as far as the confluence of the Jorquera, Pulido, and Manilas, which, from my 

 determinations of the geographical position of Copiapo, and the bearings and distances thence 

 of Prof. Domeyko, will be near latitude 27 56' south, and longitude 69 5(X west. The 

 elevation of this confluence is somewhat less than 4,000 feet, and it is below this only that the 

 river takes the name Copiapo. A more detailed notice of the valley, or rather ravine, as far 



