88 



SOCIAL EVOLUTION 



a complete gap between the river-drift culture and tlie 

 neolithic culture. Future discoveries may show that the 

 transition from the rough stone age was not as abrupt 

 as was first supposed. At any rate, with the glacial evi- 

 dence at hand, we are quite justified in the theory that 

 out of the intensified struggle for existence consequent 

 upon the overcrowding of peoples in the somewhat lim- 



Aftcr Capitan and Brcuil. 



FIGURE 38. Red Drawing of a Rhinoceros, from Font-de-Gaume. 



ited territory south of the ice front, only the most dura- 

 ble cultural elements in connection with higher mental 

 types of men survived. Isolation never develops the 

 finer sensibilities and qualities which come with the 

 mingling of peoples. Sparse and widely separated 

 groups of men such as must have existed during the 

 inter-glacial ages of the Paleolithic period, lacked the 

 conditions for the development of high culture. When 

 the cold increased and the ice once again pushed south- 

 ward, these primitive men were exterminated or else 

 slowly migrated to more temperate climates. Here the 

 peoples were more in touch with one another and popu- 

 lation was relatively dense. Under these conditions the 

 struggle for food and space was more acute. The dull 



