34 OSBORN . 



This arrangement is mainly upon the authority of Deperet. 



It is important to note that Boule, another eminent French 

 authority, differs in the arrangement of the PHocene in particu- 

 lars which will be discussed later. 



To the north, in the Red and Norwich Crags of England, are 

 said to appear the earHest arctic types of shells, the prophets of 

 the glacial period. Also here (Norwich Crag) occurs the 

 earliest giant beaver TrogoiitJicriiiin ininus. The roe and stag 

 deer become varied in southern France. 



VII. PLEISTOCENE 



In the Pleistocene period the fullness of European, investiga- 

 tion is in strongest contrast with the indecisiv^e results of Ameri- 

 can work and in no other period can we anticipate more weight}^ 

 inductions from Holarctic correlation. The period is distin- 

 guished as the Ice Age and bv the first recorded traces of man 

 in beds which have been claimed as Tertiar}' but are properly 

 Quarternar}^ 



The Pleistocene histon,' of Europe is still in a formative stage 

 but it is absolutely evident that a final and positive time scale 

 and subdi\ision of the earlv Age of ]\Ian is not far distant and 

 that the vast labors of European geologists, botanists, zoologists, 

 palaeontologists and anthropologists will be rewarded with a 

 harmonious theor}" of all the phenomena of the Pleistocene. 



Combined attack by geological and biological methods has 

 nowhere produced more brilliant results. The unaided testi- 

 mony of the rocks and soils fails to tell us of the successive ad- 

 \'ances and retreats of the ice but where, owing to the oblitera- 

 tion of surface deposits, geology is in confusion, plant and animal 

 life serv^es both biolog}^ and meteorology like a vast thermome- 

 ter actually recording within a few degrees the repeated rise and 

 fall of temperature. This record consists of the invading and 

 retreating life waves of river, forest, field, barren ground, 

 steppe, tundre and arctic types with increasing cold, or the re- 

 versed order with diminishing cold, in the same localities or geo- 

 graphical areas. There seems to be sufficient evidence for a 

 subdivision of the Pleistocene as shown in the Table below. 



