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VI.—On Changes of Climate during the Glacial Epoch

Published online by Cambridge University Press:  01 May 2009

James Geikie
James Geikie
Affiliation:
District Surveyor of the Geological Survey of Scotland.
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Extract

In a former paper I referred very briefly to the succession of glacial deposits in Switzerland. It was stated that no interglacial beds like those of Scotland and America occur in the Swiss grundmoräne. But, as every geologist is aware, Professor Heer and others have shown that the lignite-beds of the Cantons of Zurich and St. Gall are really of interglacial age, since they not only rest upon but are covered by glacial deposits. There can be but one opinion as to the position in the series occupied by these lignite-beds; they are clearly intermediate in date between the accumulation of the old grundmoräne and the deposition of that “moraine rubbish” which marked the new advance of the glaciers. ‘This being the case, they cannot represent the beds that occur in the “till” of Scotland, but must belong to a later stage. If this correlation be correct, it seems to me that the Swiss beds will serve partly to fill up a great blank in our record, and help us to realize the condition of our country in the long ages that elapsed between the disappearance of the great confluent glaciers and the subsequent period of submergence, which gave rise to the “kames” and “esker-drift.” This will appear probable, as I hope to show, after we have taken a glance at the glacial deposits in the north of Italy.

Type
Original Articles
Information
Geological Magazine , Volume 9 , Issue 96 , June 1872 , pp. 254 - 265
Copyright
Copyright © Cambridge University Press 1872

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References

page 254 note 1 For convenience of reference, the following is the order of appearance of the earlier portions of Mr. James Geikie's paper “On Changes of Climate during the Glacial Epoch.”

page 254 note 2 Geol. Mag., Vol. IX., p. 61.

page 254 note 3 The mammalian remains associated with the lignite-beds are Elephas antiguus, Rhinoceros Merkii, Jaeg., Bos primigenius, Cervus elaphus, and Ursus spelœus. See Die Urwelt der Schweiz, p. 497.

page 254 note 4 Geol. Mag., Vol. IX., p. 62.

page 254 note 5 Bull de la Soc. géol. de France, tom, vii., 2me. série, p. 554.

page 255 note 1 In a recent memoir Gastaldi takes no notice of the Dürnten beds, and continues to describe the Italian deposits as belonging to the Pliocene. [See Studii sulle Alpi Occidentali; Mem. del R. Comit. Geol. d’Ital., vol i., 1871.]

page 256 note 1 Antiquity of Man, p. 313.

page 257 note 1 Unless, indeed, some of those large erratics which are found upon the hills above Turin be the representatives of the older Swiss moraines. Gastaldi, however, believes them to be of Miocene age.

page 257 note 2 When, some time ago, I communicated to my friend, Prof. Ramsay, a rough outline of these suggestions, I was pleased to hear from him that he had long been of opinion that the plain upon which Aosta stands is an old rock-basin filled up with alluvium, and that there are others of the same kind between that and Ivrea. “These are common,” he says, “in many of the great Alpine valleys, and in Cumberland they are very frequent.” [Similar phenomena, I may add, occur in Scotland.] There is no reason, Prof. Ramsay thinks, why the old ossiferous alluvium described by Martins and Gastaldi, should be called Pliocene, and perhaps as little for referring to that period the marine sands with shells. These beds might be of the same age as the Cromer Forest bed, or even much younger.

page 258 note 1 Geol. Mag., Vol. IX., p. 23.

page 259 note 1 If the upheaval in the south of Europe at all equalled the depression in the north, it can hardly be doubted that there would be land communication between Africa and Europe—the soundings between Sicily and Cape Bon indicating the presence of a submarine ridge within less than 100 fathoms from the surface.

page 260 note 1 Gastaldi, Lake Habitations and Prehistoric Remains in Italy.

page 261 note 1 Journal of a Boat Voyage through Bupert's Land, vol. ii., p. 210.

page 261 note 2 Middendorf told Sir C. Lyell that he had observed erratic blocks in strata of clay and sand at about fifteen feet above the sea in lat. 75° 15′ N., near the river Taimyr. (Principles, vol. i., p. 185, tenth edit.) But these erratics were probably carried down by river-ice.

page 264 note 1 I learn from Mr. A. E. Jörnebohm, of the Geological Survey of Sweden, that in that country there are two Tills, both of which he considers to be true moraines de fond. He says that “the line of demarcation between them is generally very sharp, and in some places the lower till has evidently been partly broken up, and denuded before the upper till was deposited.” “These facts,” he continues, “seem to point out that during the glacial period there was a great interval of comparatively mild climate, when the ice retreated to the mountain regions; the land, however, was not submerged. Freshwater and superficial deposits that gathered during that interval may have been completely destroyed by the returning ice.”