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stone and watery deposits five times alternately had been spread out. The ocean which received such thick masses must have been profoundly deep; but again the subterranean forces exerted themselves, and I now beheld the bed of that ocean forming a chain of mountains more than seven thousand feet in height. Nor had those opposing forces been idle which are always at work wearing down the surface of the land: the great piles of strata had been cut through by many wide valleys, and the trees, now changed into silex, were exposed projecting from the volcanic soil (now changed into rock), whence formerly, in a green and budding state, they had raised their lofty heads. Now all is utterly irreclaimable and desert; even the lichen cannot cling to the stony casts of former trees. Vast and scarcely comprehensible as such changes must ever appear, yet they have all occurred within a period which is recent when compared with the history of the Cordillera; and the Cordillera itself is absolutely modern as compared with many of the fossiliferous strata of Europe and America.
In the valley of Copiapó, in northern Chile, I stayed two days collecting fossil shells and wood. Great prostrate silicified trunks of trees were extraordinarily numerous. I measured one which was fifteen feet in circumference. How surprising it is that every atom of the woody matter in this great cylinder should have been removed, and replaced by silex so perfectly that each vessel and pore is preserved! These trees all belonged to the fir-tribe. It was amusing to hear the inhabitants discussing the nature of the fossil shells which I collected, almost in the same terms as were used a
century ago in Europe, namely, whether or not they had been thus "born by nature."
AN OLD SEA-BED.
THE landscape has a uniform character from the Strait of Magellan along the whole eastern coast of Patagonia to the Rio Colorado; and it appears that the same kind of country extends inland from this river in a sweeping line
as far as San Luis, and perhaps even farther north. To the eastward of this curved line lies the basin of the comparatively damp and green plains of Buenos Ayres. The sterile plains of Mendoza and Patagonia consist of a bed of shingle, worn smooth, and accumulated by the waves of the sea;
while the Pampas, covered by thistles, clover and grass, have been formed by the ancient estuary mud of the Plata.
THIS day (Febuary 20, 1835) has been memorable, in the annals of Valdivia, for the most severe earthquake experi enced by the oldest inhabitant. I happened to be on shore, and was lying down in the wood to rest myself. It came on suddenly, and lasted two minutes, but the time appeared much longer. The rocking of the ground was very sensible. There was no difficulty in standing upright, but the motion made me almost giddy; it was something like the movement of a vessel in a cross-ripple, or still more like that felt by a person skating over thin ice, which bends under the weight of his body.
A bad earthquake at once destroys our oldest associa tions: the earth, the very emblem of solidity, has moved beneath our feet like a thin crust over a fluid; one second of time has created in the mind a strange idea of insecurity which hours of reflection would not have produced. In the forest, as a breeze moved the trees, I felt only the earth tremble, but saw no other effect. Captain Fitz Roy and some officers were at the town during the shock, and there the scene was more striking; for although the houses, from being built of wood, did not fall, they were violently shaken, and the boards creaked and rattled together. The people rushed out-of-doors in the greatest alarm. The tides were very cu riously affected. The great shock took place at the time of
low-water, and an old woman who was on the beach told me that the water flowed very quickly (but not in great waves) to high-water mark, and then as quickly returned to its proper level; this was also evident by the line of wet sand.
On the fourth of March we entered the harbor of Concepcion. While the ship was beating up to the anchorage I landed on the island of Quiriquina. The mayor-domo of the estate quickly rode down to tell me the terrible news of the great earthquake of the 20th: "That not a house in Concepcion or Talcahuano (the port) was standing; that seventy villages were destroyed; and that a great wave had almost washed away the ruins of Talcahuano." Of this latter statement I soon saw abundant proofs, the whole coast being strewed over with timber and furniture, as if a thousand ships had been wrecked. Besides chairs, tables, bookshelves, etc., in great numbers, there were several roofs of cottages, which had been transported almost whole. The storehouses at Talcahuano had been burst open, and great bags of cotton, yerba, and other valuable merchandise, were scattered on the shore. During my walk around the island I observed that numerous fragments of rock, which, from the marine productions adhering to them, must recently have been lying in deep water, had been cast up high on the beach; one of these was six feet long, three broad and thick. I believe this convulsion has done more to lessen the size of the island of Quiriquina than the ordinary wear-and-tear of the sea and weather during the course of a whole century. The next day I landed at Talcahuano, and afterward rode to Concepcion. Both towns presented the most awful