CHAPTER XVII 

 THK PLEISTOCENE SERIES 



A. GENERAL CONSIDERATIONS 



THE term Pleistocene was used by Lyell to denote the deposits 

 which are newer tlian the Pliocene and yet not modern enough 

 to be called Recent. But different writers have different ideas as to 

 what deposits should be called Recent. It seems best to consider 

 the Pleistocene period as including all deposits in Europe which 

 are older than those containing metal implements of human 

 manufacture. 



SMI ne of these deposits have obviously been formed during a 

 tiiin- when the climate became so cold that the higher parts of the 

 country were covered with ice and snow and the North Sea was 

 more or less filled with ice. Such deposits are called Glacial, and 

 the time during which they were formed is known as the Glacial 

 period, or epoch, and sometimes as the " Great Ice Age," while 

 all the subsequent deposits can be classed as " Post-Glacial." This, 

 however, is not a satisfactory division of Pleistocene time, because 

 the Glacial deposits do not extend all over Europe, being limited 

 to its northern parts and to a certain area round the Alps. In 

 other parts of the region fluviatile, alluvial, and subaerial deposits 

 were being formed, which are of a more normal character, though 

 some of them exhibit signs of severe climatic conditions. 



The Pleistocene deposits cannot therefore be treated as one 

 consecutive series, but must be regarded as including two different 

 sets of deposits, which may be called Glacial and Non-Glacial, but 

 are only distinct from a regional point of view, some of the one 

 set being contemporaneous with the other set. Again the Glacial 

 deposits, even those of a single country like England, are not 

 easily classified ; for they vary so much in different districts and 

 are so irregularly stra tilled that correlation is difficult. There is 

 of course a general succession in time, and elaborate classifications 

 have been formulated, but these are based upon assumptions and 



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