203
saw elsewhere in Switzerland or Savoy.
The ancient chronicles which preserved the
record of this event, do not inform us whether
the fall of the mountain was preceded
by any forewarnings, that allowed the inhabitants
time to make their escape. To form
some idea of the quantity of matter that
fell, if we calculate only what covered the
part now called les Abymes de Myans,
the average depth of which cannot be
estimated at less than six yards, spread
over an extent of nearly nine square
miles, this would amount to upwards of
one hundred and fifty million cubic yards;
and we may suppose an equal quantity of
earth and smaller stones to have fallen near
the foot of the mountain; these, together,
would be more than four hundred million
tons in weight. Such an immense quantity
of matter, precipitated from the height
of three quarters of a mile into the plain,
must have produced a shock, inconceivably
vast and awful.
The rocks which fell from Mont Grenier
I found to consist of a yellowish limestone,
which was oolitic, strongly resembling the
lower oolites in Gloucestershire; a grey
limestone, harder and more crystalline than
A
lias, which, however, it may probably b e ;
and a thin slaty arenaceous limestone, very
much resembling the Stonesfield slate, on
the surface of which I observed the remaining
nacre of a shell, but I did not find any
perfect shells. There were also fragments of
a schistose chert, interstratified with some
of the limestone. On referring to Saussure,
who has mentioned the Abymes de Myans,
( Voyages dans les Alpes, vol. iii.) he says that
he discovered shells in the limestone, but
he does not state of what species. Eor-
tunately the character of the limestone of
Mont Grenier may, in some degree, supply
the place of fossil remains, in determining
to what formation it belongs, as it bears a
stronger resemblance to well known British
strata, than any other limestone I examined
in Savoy.
As Mont Grenier is a part of the same
range which extends to les Echelles on one
side, and to Aix on the other, its geology,
when once ascertained, will suffice for most
of the calcareous mountains in this part of
Savoy.
From the Abymes de Myans, looking towards
Montmelian, the mountain called
La Tuille, over that town, may be observed
P :
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