200 BOTANY. [CHAP. vn. 



almost entirely confined to Norfolk and Suffolk, the 

 fossil remains of cones of the Scotch fir, leaves of white 

 and yellow water-lilies, oak, hazel, bogbean, blackthorn, 

 etc., occur. During this period the geographical features 

 of Europe were very different to those of the present 

 time ; the Irish Sea and the English Channel had not 

 then been formed, and England at that time was con- 

 tinuous with the Continent by way of France and Spain, 

 the North Sea only extending as far south as Kent, the 

 Straits of Dover and the English Channel being formed 

 at a much later period. At this time the flora of Eng- 

 land was probably much the same as that of France, 

 Spain, and Portugal at the present day, and we have 

 remaining in the South of England a few plants that 

 have existed from that period. As examples of the 

 remains of this ancient flora may be mentioned the 

 marsh wood spurge (Euphorbia pilosa), found in Somer- 

 setshire, and at the present day a common species in 

 the Mediterranean region; the large-flowered butter- 

 wort (Pinguicula grandiflora), occurring in Ireland, and 

 Pinguicula lusitanica, found in a few places in the west 

 of England, are both characteristic Iberian plants. 



The Pleistocene or Glacial period that followed the 

 Pliocene, almost completely obliterated the existing flora 

 of Great Britain, which along with the whole of Northern 

 Europe, was completely buried beneath an ice-sheet, in 

 many places several thousands of feet thick, driving south- 

 wards before it the flora and fauna of the northern 

 portion of Europe. At this period an arctic vegetation 

 spread over Northern and Central Europe, reaching as 

 far as the Pyrenees, and accompanied by characteristic 

 northern animals, as the reindeer, etc. In England the 



