THE ART OF PREHISTORIC MEN 43 



cliff at Dover. This Pleistocene or post-glacial Tertiary 



often now called Quaternary has been so carefully 



examined that we divide it as shown on page 39 into 

 upper, middle and lower, and each of these divisions 

 into successive horizons (only a few feet thick) char- 

 acterized by the remains of different species of animals 

 and often by the differing implements and carvings as 

 well as the bones of successive races of men. 



When we are concerned with written history, ancient 

 Egypt seems to be of vast and almost appalling an- 

 tiquity; on the other hand, if we study the cave-men, 

 ancient Egypt becomes relatively modern, and the first 

 cold period and extension of glaciers, which 500,000 years 

 ago marked the passage from Pliocene to Pleistocene, 

 becomes our familiar example of something belonging to 

 the remote past beyond or below which we rarely let our 

 thoughts wander. That is a natural result of concentra- 

 tion on a special study. But it has had the curious result, 

 in many cases, of making students of ancient man un- 

 willing to admit the discovery of evidences of the existence 

 of man at an earlier date than that which belongs to the 

 deposits and remains to which their life-long studies have 

 been confined and upon which their thought is concen- 

 trated. The last 500,000 years of the earth's vicissitudes, 

 which resulted in the 250 feet of " Pleistocene " deposit 

 and the marvellous treasures of early humanity embedded 

 in them, form but a trivial postscript to the great 

 geological record which precedes it. 



No estimate can be made of the time represented 

 by the 65,000 feet of fossiliferous strata known to us and 

 the same thickness of non-fossiliferous deposit which pre- 

 cedes them. There are no facts known upon which a 

 calculation of the related lapse of time can be based. 

 But most geologists would agree that whilst we have good 

 ground for assigning half a million years to the formation 



