346 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 83 



The indications, for the present, seem however to be the following : 

 (i) The Penck-Briickner conception of the Ice Age, as composed 

 of four distinct periods of glaciation with three well-marked inter- 

 glacial periods, is hard to harmonize with either the paleontological or 

 the human evidence. Both of these tend to show rather but one main 

 interglacial interval, from which there is a gradual progression to- 

 wards an irregular cold period, after which follows an irregular post- 

 glacial. There is no marked faunal reaction that would correspond 

 to the assumed third (Riss-Wiirm) full, warm interglacial. There is 

 evident no substantial change, such as would necessarily be brought 

 about by a marked alteration in climate, in man's housing and living 

 habits from the middle Mousterian to the Magdalenian cultural 

 periods. 



(2) The Mousterian or Neanderthal phase of man begins appar- 

 ently towards the end of the warm main interglacial. It is the period 

 of the gradual cooling preceding the last main ice invasion, and the 

 Neanderthal man reaches to, and probably somewhat beyond, the 

 culmination of this invasion. If there had been two general ice periods 

 separated by a substantial warm interglacial (the 3rd), then it would 

 be necessary either to extend the existence of the Neanderthalers 

 over the whole interglacial and much of the 3rd glacial — for which 

 neither archeology nor paleontology affords any substantiation ; or 

 the Acheulian man, who followed the Chellean sometime after the 

 middle of the main (Penck's 2nd) interglacial, would have to be 

 extended over the whole 3rd glaciation and a large portion of the 

 3rd interglacial — which is impossible. There is plainly a great need 

 here of adjustments of views between geology and prehistory. 



(3) During his existence the Neanderthal man is brought face 

 to face with great changes of environment. He is gradually con- 

 fronted with harder winters, which demand more shelter, more cloth- 

 ing, more food, more fire, and storage of provisions ; there are 

 changes in the fauna which call for new adaptations and develop- 

 ments in hunting; and there are growing discomforts with, it may be 

 assumed, increasing respiratory and other diseases, that call for new 

 efforts and seriously hinder the growth of the population. 



(4) Such a major change in the principal environmental factors 

 must inevitably have brought about, on the one hand, greater mental 

 as well as physical exertion, and on the other hand an intensification 

 of natural selection, with the survival of only the more, and perishing 

 of the less, fit. But greater sustained mental and physical exertion. 



