106 PROF. J. LOGAN LOELEY, F.G.S., F.R.G.S.^ ON THE HISTORY 



Still later, it is contended, this sea advanced sufficiently 

 westwarcjs to cover the East and the North of England, the 

 South of Scotland and a large part of Eastern and Central 

 Ireland, uhile the West and North of Ireland remained 

 connected wiih Nortli Scotland and its islands on the west and 

 north hy continuous land. Subsequently a general elevation of 

 Xorthern Europe laid bare an immense area of sea-bottom 

 which established land communication betw^een Western Europe 

 and Asia, north of the Caspian Sea, and gave the configuration 

 of land and water very much as it is at present, completed by 

 the cutting through of tlie Straits of Dover and the Straits of 

 Gibraltar. 



Autochthonous Species. 



By far the greater number of the animals at present or 

 recently living in Europe, and those now extinct but which 

 lived in the European area during the Pleistocene or Pre- 

 historic Quaternary period, have had for their original homes 

 areas outside European boundaries. But there are a certain 

 number of species which appear to have originated within the 

 area of the European continental platform. 



These autochtlionous animals, as they have been called, 

 n])pear to have spread in various directions from certain limited 

 regions, or, it may be said, centres, which have been determined 

 by the present extension and distribution of these species. 



Three European areas of dispersion of autochtlionous animals 

 seem to have existed. The earliest has been called the 

 Lusitanian region of dispersal, although it is much more 

 extensive than Lusitania or Portugal, since it comprehends the 

 whole of the present Iberian peninsula with the north-west of 

 Africa, and an area that extended westwards into the Atlantic. 

 Another was a south-eastern region, comprising the Balkan 

 peninsula, and a third was the central mountainous area of the 

 Alps and its extensions. 



The most important of these was undoubtedly the south- 

 western or Lusitanian region, from which area species migrated 

 northwards, north-eastwards and eastwards. The northward 

 migration was favoured by the Atlantean extension of the 

 continent wliich gave a direct land communication w^estwards 

 of the ]>ay of liiscay for Lusitanian species to reach the South- 

 West of England and Ireland. And thus it is that these areas 

 contain both plants and animals not found in other parts of 

 the P>ritish Islands or on the continent of Europe except in the 

 south-west. 



