322 SUCCESSION OF GLACIAL DEPOSITS. cuap. xv. 



many centuries, or 100,000 years, all referable to the fourth 

 period mentioned in the preceding page, or that which fol- 

 lowed the last retreat of the great glaciers.* 



If the lower flattened cone of Tiniere 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 2^>'inuge- 

 nius 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 Swit- 

 zerland. 



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, Avhen 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 lower- 

 ing 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 ])lace when man and the ex- 

 tinct mammalia were colonizing the northwest 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 re- 

 lations of the periods of upheaval and subsidence of areas so 



* Morlot, Terrain quaternairc clu Vaudoise des Sciences Naturcllcs, No. 

 Bassin de Leman, Bulletin de Suciete 44. 



