I: î :
258 F O l l T O F L E C L U S E .
she was leaning with her back against a
table, and she was suddenly thrown forward
into the middle of the room ; indeed, the
shock appears to have been more violent in
the vicinity of the Rhone than elsewhere,
in its course from Geneva to Lyons. We
arrived at the fort of L ’Ecluse about five
o’clock. This fort, situated in the narrow
defile through which the Rhone escapes
from the basin of the lake, may be said to
command the entrance into France. The
situation was well described by Cæsar :
Iter angustum et difficile inter montem Juram
et jlumen Rhodanum, vix qui singuli curri
ducerentur; mons altissimus impendehat, ut
facile perpauci prohibere possint.— De Rello
Gallico, lib. i. chap. 6. “ A narrow and
difficult road between Mount Jura and the
river Rhone, where there is scarcely room
for a single carriage to pass, and a high
mountain hangs over, so that a very few
men might prevent all access beyond it.”
The great features of the place remain the
same, but the road has been enlarged. The
fort is situated at a considerable height
above the bed of the river, but is overhung
by the very high mountain mentioned
by Cæsar.
Few persons accustomed to the examination
of strata, can reasonably doubt that
the mountain called the Vouache, on the
south side of the Rhone, and the Jura, on
the north side, were once united. At that
period, the waters in the basin of the Lake
of Geneva must have filled the whole valley
to a great height. By what means was
the present passage for the Rhone opened ?
This question has long divided the opinions
of geologists. I believe the late M. De
Luc maintained that the strata on each side
of the Rhone dip towards the river, and
that therefore the passage is coeval with
the Jura itself; but this opinion is obviously
erroneous, for though the strata of
the Jura, before arriving at the passage of
L ’Ecluse, dip south-easterly to the valley
of Geneva, yet the Vouaches and the Jura
range nearly north at this passage ; and the
Rhone, running westward, cuts the strata
on both sides (which are almost verücal)
at right angles. Those who are acquainted
with St. Vincent’s Rocks, near Rristol, may
form a tolerably correct idea of the passage
of L ’Ecluse ; but the Avon runs between
strata that dip at an angle of about 45 ,
whereas the strata on each side of the
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