

\ 



Ch. X.] 



INTER-GLACIAL PERIODS 



195 



J 



H 



H 







k 



\ 



ft 





N . 



tl 



1 



hi 





i 



irfr 

 r e bee 



on 



11 





i. 

 ■ of the 



ii south 

 It™ 



ited on 



lOTQUS to 









¥ 





Europe, and even to 46 



marked 



su- 



ae cumulatio: 



as 



to be quite without parallel in corresponding latitudes in 

 the present state of the globe, whether in the northern or 

 southern hemisphere* 



Some marine shells of living arctic species, and which no 



longer frequent the 



temperate latitudes, have been 



Nort 



America ; 



from 



former 



prevalence of a climate now proper to polar latitudes through- 

 out a great part of Europe. 



mar 



of the land since the commencement of the Glacial Epoch were 

 proved to have taken place. The change of level in Scotland, 



demonstrated 



North 



to 1,400 feet : 



ements 



t 



tertiary times, or within the period of the living testacea. Bui 

 Professor Bamsay infers, from the position of the stratified 

 drifts of the Glacial Period in North Wales, that the full 

 extent of the vertical movement which brought about first 

 the submergence and then the re-emergence of the land ex- 

 ceeded 2,000 feet. 



Inter-glacial Periods. — Without entering in this place into 

 the proofs of two continental periods in Britain during the 

 Glacial Epoch, separated from each other by a long interval 

 of submergence, during which Great Britain and Ireland were 

 in the state of an archipelago of small islands, it may be 

 affirmed that the excessive cold lasted for a long series of 



intensity. As illus- 

 trative of the fact of the cold having been intermitted or 



same 



sometimes mitigated for a season, may be mentioned what 



Hugrh Miller 



striated pavements/ 



These 



consist of horizontal surfaces of boulder clay, in which the 

 imbedded boulders are seen to have been- subjected to a pro- 



similar 



below 



had previously undergone. In such instances large stones 

 °r blocks fixed in the clay have not only their original and 



o 2 



