File:The Quarterly journal of the Geological Society of London (1862) (14761286061).jpg

Identifier: quarterlyjourna181862geol (find matches)
Title: The Quarterly journal of the Geological Society of London
Year: 1845 (1840s)
Authors: Geological Society of London
Subjects: Geology
Publisher: London (etc.)
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Biodiversity Heritage Library

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highly disturbed strata. I could enter on details to prove this point,but they belong rather to the rock-geology of Switzerland than to thematter in hand. 4th. Those who do not believe in the existence and excavatingpower of great and sudden cataclysmal floods will at once see thatthe area of the lake cannot be one of mere watery erosion; for ordi-nary running water, and far less the still water of a deep lake, can-not scoop out a hollow nearly 1000 feet in depth. Now, if the Lake of Geneva do not lie in a synclinal trough, in anarea of subsidence, in a line of fracture, nor in an area of mereaqueous erosion, we have only one other great moulding agency leftby which to modify the form of the ground, namely, that of ice. When at its largest, the great glacier of the Rhone (No. 1 of theMap, PL VIII.) debouched upon the Miocene beds where the easternend of the Lake of Geneva now lies. The boulders on the Jura, near* Edinburgh Philosophical Journal, 1820, vol. ii. p. 107, and plate 2. o 2
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1862.) RAMSAY GLACIAL ORIGIN OP LAKES. 195 Neuchatel, at the point on the Map marked B, prove that this glacierwas about 2200 feet thick where it abutted on the mountains • and,where it first flowed out upon the plain at the mouth of the valleyof the Rhone, the ice, according to Charpentier, must have beenat least 2780 feet thick *. Add to this the depth of the lake, 984feet, and the total thickness of the ice must have been about 3764 feetat what is now the eastern part of the lake, fig. 2f. I conceive, then,that this enormous mass of ice, pushing first north-west and then partlywest, scooped out the hollow of the Lake of Geneva most deeply in itseastern part opposite Lausanne, where the thickness and weight of ice,and consequently its grinding power, were greatest. This weight de-creasing as it flowed towards the west, from the natural diminutionof the glacier, possessed a diminishing eroding power, so that lessmatter was planed out in that direction, and thus a long rock-basinwas

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