the range, at an elevation of about seven thousand feet, I observed on
a bare slope some snow-white projecting columns. These were petrified
trees, eleven being silicified, and from thirty to forty converted into
coarsely-crystallized white calcareous spar. They were abruptly broken
off, the upright stumps projecting a few feet above the ground. The
trunks measured from three to five feet each in circumference. They
stood a little way apart from each other, but the whole formed one
group. Mr. Robert Brown has been kind enough to examine the wood: he
says it belongs to the fir tribe, partaking of the character of the
Araucarian family, but with some curious points of affinity with the
yew. The volcanic sandstone in which the trees were embedded, and from
the lower part of which they must have sprung, had accumulated in
successive thin layers around their trunks; and the stone yet retained
the impression of the bark.
It required little geological practice to interpret the marvellous
story which this scene at once unfolded; though I confess I was at
first so much astonished that I could scarcely believe the plainest
evidence. I saw the spot where a cluster of fine trees once waved
their branches on the shores of the Atlantic, when that ocean (now
driven back 700 miles) came to the foot of the Andes. I saw that they
had sprung from a volcanic soil which had been raised above the level
of the sea, and that subsequently this dry land, with its upright
trees, had been let down into the depths of the ocean. In these
depths, the formerly dry land was covered by sedimentary beds, and
these again by enormous streams of submarine lava--one such mass
attaining the thickness of a thousand feet; and these deluges of molten
stone and aqueous 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 antagonistic forces been
dormant, which are always at work wearing down the surface of the land;
the great piles of strata had been intersected 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 adhere 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,
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