72 



SOCIAL EVOLUTION 



tinct, or no longer the same as those in the surrounding 

 waters. 30 But while the position in or under the drift 

 which some glacier or glacial river has transported and 

 finally deposited in ever accumulating layers constitutes 



FIGURE 26. Diagram of Cro-Magnon Grotto, where Remains of Pre- 

 historic Men were found. 



quite conclusive evidence, the position under stalagmite 

 beds and kitchen-middens does not furnish as reliable 

 proof of antiquity. The growth of stalagmite beds is 

 irregular and depends upon conditions which are sub- 

 ject to some variation. In the case of the kitchen-mid- 

 den, some shells are accumulated with great rapidity 

 so that in a comparatively short time a considerable pile 



soReane, op. cit., pp. 76-77, 96. 



