334 A. C. Ramsay on the Glacial origin of certain Lakes 
been denuded, and the lake runs in a great degree across their 
2nd. For reasons already stated, it is, I believe, impossible to 
prove that the lake lies in an area of special subsidence, all the 
probabilities being against this hypothesis. 
3rd. It is almost needless to say that the Lake of Geneva 1s 
too wide to lie ina mere line of fracture; and I know of no 
reason why the valley of the Rhone, where occupied by the 
delta, should be esteemed a line of fault or gaping fissure, an 
more than many other valleys in Switzerland, which many geo! 
ogists will consider with me chiefly the result of the old an 
long-continued subaerial denudation of highly disturbed strata. 
I could enter on details to prove this point, ‘but they belong 
rather to the rock-geology of Switzerland than to the matter m 
and. 
4th. Those who do not believe in the existence and excavating 
power of great and sudden cataclysmal floods will at once se 
that the area of the lake cannot be one of mere watery erosion; 
for not ordinary running water, and far less the still water of 4 
deep lake, can scoop out a hollow nearly 1000 feet in depth. 
ow, if the lake of Geneva do not lie in a synelinal trough, 
in an area of subsidence, in a line of fracture, or in an area 
mere aqueous erosion, we have only one other great moulding 
agency left by which to modify the form of the ground, namely, 
at of ice. ; 
When at its largest, the great glacier of the Rhone debouched 
upon the Miocene beds where the eastern end of the Lake - 
Geneva now lies. The bould the J near Neue 
now li e boulders on the Jura, ee 
prove that this glacier was about 2200 feet thick w i 
he mountains; and, where it first flowed out upon” ” 
plain at the mouth of the valley of the Rhone, the ice, acco 
to Charpentier, must have been at least 2780 feet thick. A of 
to this the depth of the lake, 984 feet, and the total thickness 
the ice must have been about 3764 feet at what is now the 
ern part of the lake. I conceive, then, “a 
mass of ice, pushing first northwest and then partly W ja 
scooped out the hollow of the Lake’of Geneva most deeply a 
its eastern part opposite Lausanne, where the thickness 2”) 
weight of ice, and consequently its grinding power, were gre!" 
This weight, decreasing as it flowed towards the west, ean 
natural diminution of the glacier, possessed a dime i 
ding power, so that less matter was planed out in that 41 oe 
and thus a long rock-basin was formed, into which the wale ¥ 
the Rhone and other streams flowed when the climate amet""™ 
and the glacier retired. 
_— first d | een Lausanne and Vevay; and then 
the general slope northwards to the Jura. 
that this enormous 
Jiorated 
PE iar epadtaclahaen pies 197 feet lower than the Lake of Neucbite ed 
