Eleventh.—The road by the Planchon leads to Curico and Talca, following the courses of the rivers Claro and Teno:—on neither of these roads does the elevation exceed 11,000 feet, or the vegetation ever cease.
The twelfth pass is that of Antuco, from which Cruz started in 1806 to cross the Pampas to Buenos Ayres:—the road by it to Conception in Chile follows the valleys of the rivers Laxa and Biobio. To the south of the volcano in the vicinity of this pass, which Cruz could not get up, but which has since been ascended by M. Pæppig, a German naturalist (who nearly lost his life in the attempt), lies a ridge called the Silla Velluda, rising, according to his estimation, to the height of 17,000 feet, on the rugged sides of which, below the snow and glaciers, are to be traced ranges of basaltic columns.
Of the most frequented of these passes, viz., those by Uspallata and the Portillo, there are, as I have already said, several accounts in print, but, as I know of no other Englishman except the late Dr. Gillies who has examined those of Las Damas and the Planchon with any attention, I shall here quote part of a letter which he wrote to me in 1827, giving an account of a short excursion he made by them in that year; and I do so the rather because it also gives some account of the intervening country, which has never, as far as I know, been described by any one else:—
"About the middle of May I returned from an excursion of ten weeks to the south which I had long meditated. After reaching the river Diamante, the southern boundary of the province of Mendoza, I crossed that river and ascended the Cerro del Diamante, and at every step found ample evidence of its volcanic origin: the ascent was covered with masses of lava, and near the summit with loose pumice. The upper part of the mountain consists of a ridge elevated a little at each of the extremities into a rounded form, on the north side of which, a little below the summit, is a plateau about 400 yards in diameter, which undoubtedly has been formerly the crater of a volcano. The whole mountain appears to rest on an immense bed of pumice-stone. On the steep banks of the Diamante opposite to it such strata are laid open on both sides:—at one place on the south bank I traced one great mass of pumice-rock, 100 feet long and 145 wide, the whole forming distinct basaltic pillars.
"From this interesting spot we proceeded towards the mountains of the Andes, and amongst the first low hills examined several springs of petroleum, about which it is curious to observe the remains of a variety of insects, birds, and animals, which, having got entangled there, have been unable to extricate themselves:—so tenacious is this substance that (as I was assured by an eye-witness) some years ago a lion was found in the same situation, which had made fruitless attempts to escape. Following the base of this lower range southward, after a few leagues we reached the banks of the river Atuel, a copious stream much larger than either the river of Mendoza or the Tunuyan:—its bed, very unlike that of the Diamante, is very little lower than the surrounding plains, which gradually slope off to the eastward for twelve or fourteen leagues, as I had an opportunity afterwards of observing.
"The north bank, where we crossed it, seems admirably adapted for an agricultural settlement: it is there that the several roads diverge across the Cordillera to San Fernando, Curico, and Talca, in Chile; and to the south into the country of the Indians. We proceeded from thence towards the Planchon, along a succession of valleys rich in pasturage, but very bare of shrubbery: in several places we saw immense masses of gypsum, and passed a mountain from which is obtained an aluminous earth, much used in Chile as a pigment for dyeing. The pass of the Planchon is along the north shoulder of a lofty mountain, apparently composed of sonorous slaty strata. My barometer unfortunately got out of order before I reached the highest elevation; but, as vegetation extends to the top of the pass, it must be considerably lower than the passes of the Portillo and of Uspallata, on both of which all vegetation ceases long before reaching the higher points of the road. The descent from the Planchon is very rough, and in many places steep: at a distance of three leagues from the top we reached our resting-place, surrounded by luxuriant vegetation, and thence descended to Curico, along a valley with steep mountains on either side, and through a continuous thicket of lofty trees and shrubs, amongst which I may enumerate the Chilian cypress, the quillay, the canelo or cinnamon-tree, the caustic laurel, a variety of myrtles, a beautiful fascia, and others no less interesting.
"From Curico we went to Talca, a considerable town, and thence explored the river Maule, with a view to its capabilities for navigation. We returned by Curico to San Fernando, where we re-entered the Cordillera by the valley of the Tinguiririca to ascend the pass of Las Damas: the road was very similar to that we had previously descended from the Planchon to Curico; but, being much less frequented, it was in many places difficult and dangerous. In the upper part of this valley we examined some hot springs, the temperature of which reached 170° of Fahrenheit. Thence we were induced to devote two days to visit a volcano,—which was described to us as being in an active state,—about ten leagues distant: thither we proceeded by a most rugged and dangerous path, and reached within half a league of the summit, when so serious a snow-storm came on, that we had the mortification of being forced to return without accomplishing our object; nor had we any time to lose, for the snow had so completely obliterated all traces of the way, that our guide was completely lost, and, but for the observations I had taken with my compass, I know not how we should have got back at all. On reaching our mules again, the weather was so unpromising that we made all haste to recross the mountains, lest they should be closed against us by the heavy snow which was falling; this we happily accomplished, and three days brought us back again to the place where we had first crossed the Atuel river. After visiting the extensive saline lakes in that vicinity, from which the province is supplied with salt, we bent our way back to Mendoza.
"In this journey I had an opportunity I had long desired of examining on the Cordillera the plant from the root of which the natives of Chile obtain their admirable red dye."
Dr. Gillies, the writer of this letter, passed many years at Mendoza, where he recovered from a severe pulmonary affection, and was himself a striking instance of the beneficial effects of the climate under such circumstances. Botany was his favourite pursuit; but he did not confine himself to this, and never lost an opportunity of collecting useful information on every other point which fell under his notice.
His botanical acquisitions were, I believe, chiefly communicated to Professor Hooker, of Glasgow, through whom they were occasionally made known to the public. His collections of the ores of Uspallata and other parts of the Cordillera were given to the College Museum at Edinburgh. I am myself indebted to him for the best part of my information respecting the provinces of Cuyo. It was through him I obtained, amongst other curiosities from those parts, the very remarkable little animal which is figured in the annexed plate, and which is now in the collection of the Zoological Society of London. It has hitherto been only found in the provinces of Cuyo, and even there but rarely: it burrows in the ground, and in its habits somewhat resembles the mole, lying dormant during the winter months; the natives call it the Pichi-ciego. Dr. Harlan, of New York, was the first to give an account of it, from an imperfect specimen sent to him from Mendoza; and he gave it the name of chlamyphorus truncatus.