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stone, with calcareous cement, lying in different places at their basis, composed of the
same species of white sand found on the summit of the Salêve, in strata of two or three
feet thickness, that the rocks which now appear as though shooting out of the ground,
and resdng against its basis, are a small part of the total mass only, the rest having since
been covered, or entirely buried, by fragments of the same mountain and successive
sediments of the sea.
Finally, there can remain no doubt of the great revolutions and commotions of
Nature experienced in that mountain at a date much anterior to the one which has
given it the form it now has, if those parts contiguous to the villages of CoUonge and
Le Coin be attentively examined. Tliere immense, fragments, formed by a number of
huge rocks, are conspicuous, which, by their mass, literaUy appear like small or lesser
mountains, placed at the basis of the Saleve : many of them, which are of a pyramidical
figure, are upwards of three hundred feet in height. But what appears more surprising,
and again more forcibly corroborates my idea of the severing or breaking of the mountain,
is the wide and deep fissures which exist in that part of the Salêve, and reach
from the top to the bottom, with an opening of nearly from two to three feet at their
entrance, besides caverns, which apparently extend far into the interior of the mountain,
among which are those of Balme and Orjobei : in short, the perpendicular pits,
and many other objects similar to these, equally curious and interesting to the Uthologist,
not only prove the effects and havoc of some violent débâcle, but likewise those of an
impetuous current, whose direction tended from north-north-east to south-south-west.
If the Salêve be considered as aboundmg with curious and singular appearances, the
Jura may also be deemed no less deservmg of notice, as must clearly have appeared
when speaking of the Dole; therefore, that I may not enlarge too much on a simUar
subject, I shall brieHy mention what will be most necessary to support my hypothesis,—
1 shall confine myself to describing the direction of its strata, which are invariably so
inclined on the side next the lake, as well as towards the north-north-western, that if it
were possible to see or examine the section of the mountain itself, those same strata,
which almost touch at the summit, would be found resting on the nucleus of the mountain,
diverging so considerably as to form a true Greek lambda (A), the top of which
would very nearly represent the summit of the Jura.
. It may however be proper to remind my reader, that I mean to be understood as
speaking only in general terms of the strata of that mountain, having before noticed
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that it would be impossible to enter into a minute detail on the subject, owing to the
great irregularity and heterogeneity of the mass. But as the nucleus of the Jura iS
visibly of the secondary class, although of calcareous species, the strata above mentioned
may be considered in great part of the tertiary, from their containing fossils. It
is consequently my firm opinion, that they doubtless are of posterior date to the formation
of the nucleus, and that they cannot have taken their present direction, unless
by some great operation of Nature, which, from their original horizontal surface, has
forced them, by some sudden sinking of the earth, to beCome as inclined as they now
appear. Hence I have also been led to infer, from the extreme irregularity and confiasion
in their direction, which in some places exhibits vertical forms, and in others zig-zags,
and sometimes seems even to describe a portion of a circle,—as likewise from the caverns
found in the interior of the mountain, the calcareous matter which in many places
covers thè summits of the Jura, as well as the monticules, or small hills, on its sideS and
basis, that several of these strata at one time communicated with those of the Salevc,
and that, from every appearance, the change in their original directiort to the present
may be reasonably presumed to have happened at the epoch when the sudden crush,
whether by external pressure, or internal expansion of aerial or igneous fluid, of the
vaulted roof that covered the immense subterraneous cavern or caverns, since forming
the Lake of Geneva, took place; for the above thiii irregular strata, filled with
marine fossils, and the hills which now lie at the foot of the same mountains, wear
visible marks of having been the last works of the sea.
Besides these instances, many others might be enumerated, which are as curious in
themselves as they would be interesting to the geologist; as, for example, 1st, the
variety of species of sand-stone, as well as beds of sand and pebbles, found on the
Salêve and the sides of the Voirons ; 2dly, the pyramidical form of the Môle, another
stupendous mountain, which lias also every possible appearance of having likewise
been the work of some rapid or impetuous current, which has, as it were, sharpened its
summit, given to it that regular slope next the lake, and extreme abruptness on its
southern side ; 3d!y, the apparent analogy which exists in both the structure and formation
of the mountains of Sion and Jorat, which seem to have also been the drain of
that extensive lake j 4thly, the different species of gypsum found along the banks of the
Rhône and near the hills of Cologny, which may be entirely attributed to a mixture of
calcareous and vitriolic earths, kept originally in a state of dissolution by the sea j 5tlily,