588 
name, de Passage de la Grotte, and les 
Echelles. A zigzag road for mules was 
afterwards eut in the rocks, so as to 
join the natural fissure, and this re- 
mained till 1670, when Charles Emanuel 
the Second, undertook to make a wider 
road along the bottom of the fissure, and 
by aseries of terraces, rising from the 
valley, a practicable descent was formed 
for all kinds of wheel-carriages. This 
road, till the time of Napotfeon, was 
considered a miracle of art, though it 
was far from affording an easy commu- 
nication bet ween Chamberry and France, 
for a voiture with four horses was 
obliged to hire eight oxen, frum the 
village below, to ascend. 
GEOLOGY. 
The strata of sandstone and limestone 
in the yalley going to the town of Echel- 
les must have undergone a great dis- 
turbance, as is proved by their occurrence 
in a vertical position at the lower end 
of the valley, though they are nearly 
horizontal at the upper end. Hence I 
‘should be inclined to helieve, tbat this 
extraordinary valley was formed by a 
subsidUney of the ground. 
The masses of limestone that form the 
castellated summits of the muuntains in 
this part of Savoy, range generally from 
3000 to 4500 feet above the level of the 
valleys, and are all probably parts of one 
vast stratum, that once was continuous ; 
but this can only be determined by an 
actual examination, which, in many in- 
stances, would be difficult to make. The 
calcareous strata here, have not the same 
regularity of dip over a considerable ex- 
tent, as the upper calcareous strata in 
England, but they very frequently dip in 
opposite directions on the opposite sides 
of the same mountain, and are nearly 
flat on the top; and, as the dip on each 
side is often very considerable, to this 
cause we may attribute the occurrence 
of caps of limestone remaining on the 
tops of the mountains, when the strata 
on the sides of the mountains have nearly 
or entirely disappeared. Where the dip 
is Iess considerable, they remain un- 
broken, forming what the Wernerians 
calla mantle-shaped stratification; which, 
however, is always more or Jess broken. 
Now, it is evident that those strata of 
limestone which contain marine organic 
remains, were formed under the waters 
of the ocean, and their original position 
must bave been nearly horizontal; at 
least, it is impossible they could have 
been deposited at an angle of sixty or 
seventy degrees, or nearly vertical; in 
which positions they very frequently oc- 
Bakewell's Travels in the Tarentuise, Sc. 
cur in this part of the Alps. It.is equally 
obvious, that strata of sandstone, or 
sandstone intermixed with rounded bol- 
ders, could not have been originally de- 
posited at angles exceeding forty-five 
degrees, or nearly vertical; in whieh 
position they are also found extending 
from the bottom to the top. of a moun- 
tain, aud preserving nearly the same 
thickness throughout their whole extent. 
In such instances, and they are of fre- 
quent occurrence, we must admit that 
the strata have changed their original 
position, and haye been elevated either 
bya subsidency of ott part of the strata, 
or by the action of some power from 
beneath, npheaving the whole mass with 
a force which was most iulense, near the 
present centre of the mountain. The 
latter appears the more probable snppo- 
sition, in all those cases where the strata 
dip in opposite directions on the opposite 
sides of a mountain, and are nearly flat 
at the top. To this breaking up of the 
strata, when the mountains were first 
raised, and to diluvial currents which 
have in remote periods passed over them, 
I am persuaded, we must resort to ex- 
plain their present appearance in this 
part of Savoy. Water-courses, or at- 
mospheric agency, however considerable 
their effects in the course of ages, appear 
altogether inadequate to occasion the 
changes the strata have obviously ander- 
gone; at least it will be admitted that 
no atmospheric action could bend strata 
of vast thickness into deep curves, or 
change their position from horizontal to 
vertical. 
Whether the caps of limestone on the 
summits of the mountains in this part of 
Savoy are all parts of one vast bed, or of 
different beds, I will not pretend to de- 
termine, as there is more than one con- 
siderable bed of sandstone interstratified 
with this limestone, and the mineralogi- 
cal characters of the upper and lower 
beds of limestone are frequently so simi- 
lar, that they are not to be distinguished. 
I am not aware that any geologist 
has hitherto adverted to the alterna- 
tion of hard and soft strata, as offer- 
sing an explanation of the furmation of 
these mountain-valleys. To me it ap- 
pears satisfactory. I am far, however, 
from believing, that all valleys were 
formed by the excavation of soft 
strata; many of the valleys in this 
part of the Alps appear most evidently 
to have been formed by a violent de- 
rangement of the strata, which has ele- 
vated them in one part and depressed 
them in another; but I must refer the 
reader 
