PLEISTOCENE OF EUROPE, NORTH AFRICA, AND NORTH AMERICA 385 



It is regarded by Schwalbe ^ either as a tlirect or indirect ancestor of the 

 human phylum, standing intermediate between the apes and man in respect 

 to its high brain capacity and the structure of its femur. It thus 

 probably belongs in the family Hominida?, and if so it had a grasping thumb. 



Duration of the Pleistocene 



The Pleistocene was estimated by Dana (1874) to be equal to one- 

 fourth of the entire Caenozoic Era; by Ward (1885) and Williams (1895) 

 it has been estimated at one-third of the entire Caenozoic Era. The tend- 

 ency of more recent thought has been altogether in the direction of length- 

 ening the duration of Pleistocene time. If with Wallace we accept CroU's 

 theory and estimate, the last glacial advance would date back to the last 

 period of great eccentricity, namely 200,000 years. The other figures show 

 the variations of opinion on this subject and the increasing tendency to 

 prolong the estimates of time. 



The more recent estimates, although made by very high and usually 

 conservative authorities, appear excessive unless we are to extend our 

 estimates of Tertiary time (see p. 63) to twenty million years, and of pre- 

 Tertiary time into hundreds of millions. 



Penck has recently^ (1908) pointed out the vast interest which attaches to 

 this duration problem in connection with the antiquity of man. He Ijelieves 

 that the whole Ice Age lasted somewhere between 500,000 and 1,000,000 

 years. The second, very long and warm interglacial epoch, known as the 

 Helvetian or Mindel-Riss, is alone reckoned by him at several hundred 

 thousand years, and the final short, or Riss-Wiirm, Interglacial Stage is 

 reckoned at nearly 100,000 years. Since the climax of the final, or Wiirm, 

 Glaciation he believes that from 30,000 to 50,000 years have elapsed. As 

 regards the duration of palaeolithic culture periods, the older palaeolithic, or 

 Chellean and Mousterian culture periods are of much longer duration than the 

 newer palaeolithic, or Solutrian and IMagdalenian. Since the beginning of 

 the latter, or IVIagdalenian, perhaps 24,000 years have elapsed; since its 

 end perhaps 16,000. Compared with the Palaeolithic divisions, the Neo- 

 lithic stone and metal periods have occupied an almost unappreciable length 

 of time; if the beginning of the age of metals dates back 3,000 to 3,500 years, 

 that of the Neolithic lake dwellings began about 5,000 to 7,000 years ago. 



' Rchwalbo, G., Ucbcr fossilc Primaten und ihre Bedeutung fiir dio Vorgeschichte dea 

 Menschen. Mittcil. Philomat. Ges. Elsass-Lothringcn, Vol. IV, no. 1, Decade -16 (1908), 

 Strassburg, 1909. 



- Penck, A., Das Alter des Menschengeschlechtes. Zeilschr. EthnoL, no. 3, 1908, pp. 390- 

 407. 



2c 



