122 EARLY MAN IN BRITAIN. [CHAP. v. 



The Three Divisions of the Pleistocene Age. 



As the climate in Europe changed, the Pleiocene 

 species yielded place to those which were better adapted 

 to the new conditions, either retreating southwards or 

 becoming extinct. The first division of the Asiatic 

 invaders is composed of the animals forming the tem- 

 perate group above mentioned ; they are found in the 

 early Pleistocene strata, in Britain and in France, side 

 by side with the survivals from the Pleiocene age. No 

 arctic mammalia had as yet arrived. The next stage 

 in the migration is that in which the temperate 

 group of animals had for the most part replaced the 

 Pleiocene survivals, in Britain and France, and the 

 arctic mammalia begin to appear, but only in small 

 numbers. This constitutes the middle Pleistocene 

 division. The third stage in the migration is indicated 

 by the presence in full force of the arctic species in the 

 area north of the Alps and Pyrenees. They are not, 

 however, met with south of this boundary, and therefore 

 this classification does not apply to the deposits of Spain, 

 or the other portions of the southern zone. 



It must also be noted that the temperate group of the 

 Asiatic invaders found their way over the whole of 

 southern Europe, and along the Mediterranean shores, as 

 far south as Palestine and the Sahara Desert Sicily 

 and Malta affording one line of migration southwards, 

 and the land barrier then stretching across the Straits 

 of Gibraltar offering another. 



