38 SECRETS OF EARTH AND SEA 



many thousands of years over north and middle Europe. 

 It is identical with the Palaeolithic period, which, however, 

 probably extends beyond it into the Pliocene and even 

 further back. In the later deposits of the Pleistocene, 

 which necessarily have been less frequently disturbed and 

 re-deposited than the older ones, we find more numerous 

 remains of man's handwork, and in less disturbed order 

 of succession, than in the older deposits. Lately we have 

 obtained in East Anglia beautifully-worked flint imple- 

 ments the rostro-carinate, or eagle's beaks from below 

 shelly marine deposits the Red Crag of Suffolk and the 

 Norwich Crag the oldest beds of the Pleistocene. They 

 were made by men who lived in the Pliocene period, and 

 carry the ancient Stone period of man back to a much 

 earlier period than was admitted nine years ago. 



The Pleistocene series or "system " of strata also called 

 the " Quaternary " to mark its distinction from the under- 

 lying long series of " Tertiary " strata does not comprise 

 the actual surface-deposits in which the remains of Neo- 

 lithic man are found. It is usual, though perhaps not 

 altogether logical, to separate these as " Recent " and to 

 begin the long enumeration of "geologic" strata after 

 a certain interval when the relative levels of land and sea 

 and the depth of river-valleys were not precisely what 

 they are to-day, and the human inhabitants of Western 

 Europe were hunters using rough unpolished flint imple- 

 ments in fact, when the " Palaeolithic " period of human 

 culture had not given place to the " Neolithic," which 

 was after some ten thousand years itself to be superseded 

 by the age of metals. " Prehistorians," the students of 

 prehistoric man divide the Pleistocene series of deposits 

 with a view to a systematic conception of the successive 

 changes of man and his surroundings during the period 

 occupied by their deposition, into an upper, a middle 

 and a lower group and further have distinguished certain 



