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276 M O U N T A IN OF G Y P S UM .
village called Villard Goitrou, where the
road divides, and is no longer practicable
for a char : the road on the left passes over
the mountains into the valley of the Isere,
and that on the right to Lans le Bourg, in
the Maurienne, at the foot of Mont Cenis.
The Fan de Sucre, the remarkable conical
mountain of gypsum, was now immediately
above us, on the opposite side of the
river. Seen from hence it is a most magnificent
object. Its northern extremity
presents a pyramidal mass of bare rock,
rising very precipitously from the vale to
the height of 3500 feet. As far as the fact
could be determined by its appearance, this
mountain is formed of the same mineral
substance from the summit to nearly its
base. Had the gypsum heen interstratified
with any other rock, the edges of the other
strata would have been seen projecting,
which I could not observe fo be the case.
On the eastern side of the mountain, however,
the gypsum reposes on a base of
rock of a different kind, which is much
contorted, and is either mica, or talcous
slate, similar to what abounds elsewhere in
this part of the vale, but it was inaccessible.
We had our provisions carried to the
V IL L A R D G O IT R O U . 277
base of this mountain, and dined under its
shade. The gypsum is snow-white and granular;
it resembles in its structure the purest
refined sugar. We ascended a ravine in the
mountain to some distance, and had an opportunity
of observing the beds of gypsum
which here appeared to rise to the west
north-west, and were not intermixed with
any other kind of strata.
On the road from Boshel to Villard Goitrou,
we passed similar beds of gypsum,
near the bottom of the valley. The occurrence
of a mass of gypsum, forming apparently
the greater part of an isolated
mountain, rising from 3000 to 4000 feet
above its base, is a geological fact which, as
far as my own information goes, is unique.
The northern side of the mountain, facing
Brida, is partially covered with a scanty
vegetation, and has a brownish orange-
coloured tint, which gives it a very singular
appearance. Forest trees are thinly scattered
over its base. The side opposite
Villard Goitrou is quite bare, and is covered
with débris from the summit. From the
natural softness of this species of gypsum,
a mountain of so great an elevation, and
rising very abruptly, must crumble and di-
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