CORRELATION OF THE TIME DIVISIONS 471 



Also to the left is the river terrace column, which furnishes the meeting 

 around or liaison, between the Penck-Briickner system of glacial stages 

 and the Deperet system of marine stages. 



It will be observed that the Sicilian stage of Deperet corresponds 

 broadly with Glaciation I and Inter glaciaiion 1 of Penck and Bruckner ; 

 that the Milazzian stage of Deperet corresponds broadly with Glacia- 

 tion II and Inter glaciation 2 of Penck and Bruckner; that the 

 Tyerhenian stage of Deperet corresponds broadly with Glaciation III 

 and Inter glaciation 3 of Penck and Bruckner; that the Monastirian 

 stage of Deperet corresponds broadly with Glaciation IV of Penck and 

 Bruckner. 



Thus the divisions of the Quaternary contained in the Deperet system 

 are practically coincident with the divisions of the Quaternary contained 

 in the Penck-Briickner system. This coincidence is very significant. It 

 shows that, according to both systems, glacial advances correspond with 

 periods of regression of the sea, elevation of the land, and erosion ; that 

 interglacial epochs correspond with periods of transgression of the sea, 

 depression of the land, and deposition. This concordance of the Penck- 

 Briickner system and the Deperet system is very important if it can be 

 firmly established by further observations. 



It leaves for future observation the primary causes of marine trans- 

 gression and regression. As pointed out in Section III (Appendix) of 

 the present contributions, Deperet holds to the eustatic theory; he be- 

 lieves the primary cause of marine transgression is the actual elevation 

 of sealevel. This opinion is supported by many geologists and physi- 

 ographers. On the other hand the geologists and physiographers herein- 

 after quoted in the Appendix maintain that the sealevel remained sub- 

 stantially the same throughout Quaternary time; that the primary cause 

 of marine transgression is continental depression. 



Aside from these debatable aspects of the bases of Quaternary time 

 divisions, figure 13 marks a profound change in the opinion of the joint 

 authors since 1914, when the first Osborn-Reeds correlation table of 

 this kind was published in "Men of the Old Stone Age." The senior 

 author now assigns a much greater antiquity to the Piltdown and Heidel- 

 berg stages in the evolution of man and to the early Chellean stage in the 

 evolution of human culture. The grounds for this are fully stated in the 

 pages and tables of the present Section II of this contribution. The 

 recent discovery of the Foxhallian industry of the Eed Crag and of a 

 still more ancient pre-Eed Crag industry profoundly modifies our former 

 relatively conservative views, both as to the antiquity of man and the 



