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calcareous bank, which impends considerably over the upper or great channel of the
Rhône. I use the word upper, or great, from its being the one into which the superflux
of the water empties itself, when its too great abundance prevents its being entirely
swallowed up in the abyss, where it vanishes for a time (no uncommon circumstance at
the melting of the snows), and in order that I may distinguish it from the other, which
is at least two and forty feet lower than the upper, but in which the river runs previous
to its arriving where it disappears.-
On this terrific bank, three and thirty feet above the bottom of the upper channel, I
remained till I had made my observations on the various directions and thickness of
the strata that compose the calcareous mountains, which rise with an abrupt ascent on
both sides of the channel, carefully examining their structure, and the species of fossils
which they contain.
Having so fer satisfied my curiosity, I descended from the bank by means of a
ladder, erected, at the expense of the inhabitants of the hamlet I had just quitted, for the
accommodation of those who are desirous of taking a nearer view of the loss of the
Rhône, and for which they receive a trifling gratuity.
This ladder is placed contiguous to the bridge of Lucey, which is thrown across
the upper channel, to serve for a communication between France and Savoy,—those
territories being there separated only by the course of that river. From the banks
of the channel I forded to the opposite side without much inconvenience from the
water, the Rhône being at that time nearly swallowed up in the opening of the rock,
which I hereafter purpose describing; but my greatest difficulty, and indeed one
which considerably impeded my progress, arose from the huge pieces of calcareous
stone which entirely cover the bottom of the channel, and which appear to be detached
fragments from the lateral rocks and mountains, as they not only contain similar fossils,
but have the same grain and colour. This last, being a dark grey, I attribute to par*,
tides of manganese mixed with the calcareous substances of which those mountains are
formed ; and I likewise remarked large masses of lenticular stone, promiscuously
placed among them, foreign to the spot where they now stand, but which are of
curious structure, from the extreme smallness of the shells which compose them. These
obstacles did not, however, prevent my observing clearly that the concealment or disappearance
of the Rhone is in part effected by the salient or prominent lower strata of
the two lateral mountains, and the immense heaps of rock above mentioned, which, by
filling the vacuum existing between those prominent strata, form a kind of vault, or
irregular cavity, into which the Rhône sinks, and loses itself ; and this vault, or irregular
cavity, which is reckoned to be three hundred and fifty feet in length, consritutes the
Perie du RMne. There the river disappears, and is only heard rumbling in the interior
of the mountain, near to where it again re-appears. But, in order to be better understood
by those who have never visited that curious spot, I shall here add some remarks
on the course of this noble and extensive river, previous to its losing itself.
Travelers, who have been induced to go from Geneva to Coussy, on purpose to
view this surprising effect, must have observed how greatly the bed of the Rhône contracts
as it runs between the range of hills which serve as a kind of basis to the mountains
of Jura and Vouaches -, since, contiguous to Cluse, or Ecluse, a fort situated on
the Swiss frontiers, at the entrance of the defile formed by those mountains, the course of
that river has scarcely one third of the width which it has in the vicinity of Geneva. It
is, however, certain, that the confined state of the current has dug a bed of extreme
depth, although through a number of calcareous and argillaceous strata. Many of these
strata, differing from each other in hardness, have consequently been worn through
sooner than others, and caused the water to form several natural cascades, or falls, which
announce from afar the impetuous current of the Rhône.
This diminution takes place so rapidly, that, at the bridge of Grezin, six miles from
the fort of Cluse, the same river is only a sixteenth part of its width near Geneva -, and
this contraction continues for the space of three miles ; so that, near to where it disappears,
a tall man might perhaps stride across the current, as already noticed, and thus
view passing between his legs one of the finest rivers in Europe, which, at no greater
distance than twelve miles each way, exhibits, from the impetuosity of its current, and
the width of its channel, a most noble and majestic appearance.
Desirous of giving information, yet wishing to avoid prolixity, I shall confine myself
to the following remarks, made with care and attention.—First, that the water of the
Rhône flows, for some rime previous to its loss, with great rapidity, in a deep but narr
row channel, dug by its impetuosity through calcareous strata, which, by its friction,
are nearly cut into right angles. Secondly, that these strata vary in their species, and
that those which are uppermost are in general thinner and softer than the lower.
Thirdly, that the bottom of the channel appears to be partly cut through a greyish
argillaceous matter, and partly through the soft kind of calcareous stone, but scarcely