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from Martignie to the Hospice, or convent of monks, seated on the summit of the
mountain, being computed at twenty-four. The greater part of the mountains which
screen the road from the vailey of the Rhône to the other side of the last-mentioned
village, appear to be of lamellated spathic rock, containing particles of quartz and mica,
not unlike the sûxum mixlum spathosuvi of Wallerius : but the hills are mostly composed
of fragments from the primitive mountains, which seem to be no other than true alluvions,
or mud-banks. I have however remarked, on most of their summits, large
pieces of granite, or primitive rock, of which the rounded angles and polished surfaces
sufficiently evince that they could only have been carried thither by the last retreat of the
sea, and by similar means to those which operated in the transportation of the masses
which now.lie on the top of the Salêve, &c. as before stated.
I then, at no great distance from the village of La Vallette, crossed tlie Drance (an
extensive and rapid torrent, which runs through the valley), and entered a forest of fir,
larch, and other Alpine trees. The high road, which here runs the whole length of the
same valley, in a direction tending from east to west, is beautifully romantic, following
almost every-where the course or banks of the Drance, which rolls its foaming waters in
a deep channel, apparently, at first sight, furrowed in the rock by their impetuosity, if we
may judge by the very great similarity existing in the opposite strata of the same rock,
which are abrupt on each side, having a similar direction (that is, nearly vertical), also
the same structure, and being almost every-where cut at right angles of equal heights, by
deep fissures almost parallel to the course of the torrent. These are appearances which
may be thought to indicate its original elevation. Yet, though I am not desirous of
denying the possibility of such operations, it may be reasonably presumed that the first
channel of the Drance was only a deep or large crevice effected, in the side of Uiat
mountain, or rather cliain of mountains, by some subterraneous commotion,—which
cavity or crevice, in process of time, may have been filled with fragments brought
away from the primitive mountains by the sea, during its last retreat j but that the torrent
itself, having since (by the course or velocity of its water or current) carried those
same fragments into the Rhône, the bed through which they flowed has thus gradually
and imperceptibly lowered to its present level,—a suggestion which, from a careful
view of the circumstances, I have been induced to adopt, as it appears the most
likely to account for its being filled with such enormous pieces of primitive rock, which
the waters were unable to carry off" or wash away.
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