. . . Xil
U
!• i
! ! i '«i
i ÎI|
5!
n
îA'i ■'
i1
i- r
M
Rhone dip at an angle of about 75°. It is
scarcely possible to observe the strata on
each side of the river Avon, and entertain
a doubt of their having been once united ;
and I think no one who is not misguided
by an attachment to favourite theories, can
entertain any doubt respecting the former
union of the Vouache with the Jura.
By what cause the passage of the Avon
was opened near Bristol, would be as difficult
to determine as it would be to ascertain
the formation of the passage of
L ’Ecluse between the Vouache and the
Jura ; but a rent first produced either by
subsidence or by an earthquake, appears, I
think, the most natural and probable cause
in both cases. Through this rent the
waters would rush with great impetuosity,
carrying down fragments of rock, which
would enlarge the opening, till the lake attained
its present level.
The description which Saussure has
given of the passage of I’Ecluse is so correct,
that I am surprised its accuracy can
have been disputed by any one who has
examined the place ; yet I heard it asserted
'a t Geneva, that the strata on each side of
the Rhone dip towards the bed of the river,
and leave an opening for its passage. I found
their position very different, and several
sections which I took, confirm the accuracy
of Saussure’s statement, which I
shall subjoin. “ This opening is the only
one through which the Rhone can escape
from the bosom of our mountains ; if it
were closed, our highest hills would be
submerged, and all our valley would form
one vast reservoir, the waters of which
could only escape over the summit of
Mount Sion.” *
“ I have been desirous to discover the
origin of this opening, so interesting to us,
(the Genevese,) and I have examined it
with much attention ; my observations, as
may well be supposed, have terminated in
conjectures. It is, nevertheless, probable
that this passage was originally closed, or,
at least, was far from being so deeply excavated
as at present.”
“ The mountain of the Voauche appears
to be a continuation of the first line of the
Jura. This first line, whose general direction
is north-east and south-west, changes
its position in approaching the L ’Echise,
* A continuation of the Vouaches, which joins the
S 3
gi’eat Saleve.