1880.J NATURAL SCIENCES OF PHILADELPHIA. 309 



a cold climate and a period of a flood far larger than any of late ex- 

 perience may require a long lapse of time. These considerations 

 are not within the scope of this paper. It has been the aim of the 

 writer to define the antiquit}' of man in relation to geological rather 

 than to historical events. If, in showing that the Eskimo period is 

 the last of the geological ages, it does not necessarily follow that it 

 is by anj' means recent, it must be remembered, on the other hand, 

 that its high antiquity is not proven by the facts thus far 

 observed. 



The conclusions to which the facts seem to point may briefly be 

 summarized as follows : — 



1. That the Trenton gravel, the only gravel in which implements 

 occur, is a true river deposit of post-glacial age, and the most 

 recent of all the gravels of the Delaware valley. 



2. That the palteoliths found in it really belong to and are a 

 part of the gravel, and that they indicate the existence of man in 

 a rude state at a time when the flooded river flowed on top of this 

 gravel. 



3. That the data obtained do not necessaril}^ prove, geologically 

 considered, an extreme antiquit}- of man in Eastern America. 



