many centuries, or 100,000 years, all referable to the fourth period mentioned in the preceding page, or that which followed the last retreat of the great glaciers.[1]
If the lower flattened cone of Tinière be referred in great part to the age of the oldest lake-dwellings, the higher one might, perhaps, correspond with the post-pliocene period of St. Acheul, or the era when man and the Elephas primigenius flourished together; but no human remains or works of art have as yet been found in deposits of this age, or in any alluvium containing the bones of extinct mammalia in Switzerland.
Upon the whole, it is impossible not to be struck with an apparent correspondence in the succession of events of the glacial period of Switzerland, and that of the British Isles before described. The time of the first Alpine glaciers of colossal dimensions, when that chain perhaps was several thousand feet higher than now, may have agreed with the first continental period alluded to at pp. 241 and 282, when Scotland was invested with a universal crust of ice. The retreat of the first Alpine glaciers, caused partly by a lowering of that chain, may have been synchronous with the period of great submergence and floating ice in England. The second advance of the glaciers may have coincided in date with the re-elevation of the Alps, as well as of the Scotch and Welsh mountains; and lastly, the final retreat of the Swiss and Italian glaciers may have taken place when man and the extinct mammalia were colonising the north-west of Europe, and beginning to inhabit areas which had formed the bed of the glacial sea during the era of chief submergence.
But it must be confessed, that in the present state of our knowledge, these attempts to compare the chronological relations of the periods of upheaval and subsidence of areas so
