VEGETABLE COLONIZATION. 231 



same time on the shores of the polar countries and on the snow- 

 crowned summits of the Alps of central Europe. 



Germanic type. — It is this which predominates in England, and 

 constitutes, as we may say, the basis of its vegetation. Natives of 

 the north of France and of Germany, these plants have occupied the 

 greater part of England, Scotland, and Ireland, as heretofore the 

 Saxons invaded the territories of the Angles in order to supplant them. 

 If it he true that the aboriginal owners of the country disappeared 

 after the invasion, it is thus, perhaps, that the plants of Germany 

 have stifled those which formed the primitive vegetation of these 

 islands. In the course of ages the Germanic type has become so pre- 

 dominant that most English botanists designate it by the name of the 

 British type. Nevertheless, a certain number of plants pertaining to 

 this type have never traversed the strait which separates England 

 from Ireland, while the rest of the migration transcended this ob- 

 stacle. Species common on the English coasts of St. George's channel 

 are unknown on the opposite shores of Ireland. The investigations 

 of the geologist have confirmed in every respect the inductions de- 

 rived from botany. Certain animals which occur indiscriminately in 

 Germany are in the British islands emparked, as it were, and restricted 

 to the region where the Germanic flora exclusively prevails. Thus 

 the hare, the squirrel, the dormouse, the marten, the mole, are lim- 

 ited to England, and do not appear in Ireland. In the latter island 

 five species alone represent the class of reptiles, while eleven occur 

 in England, and twenty-two in Belgium, the point of departure for 

 the Germanic migration. The living molluscs, such as the different 

 species of Helix and Clausilia, are distributed in like manner. 



The maritime fauna and flora obey all the laws which control the 

 distribution of terrestrial vegetables and animals. Certain kinds of 

 marine alga) proper to southern climates occur only on the western 

 coasts of England, where also certain species of fish are caught, which 

 never pass beyond the straits of Dover and St. George's channel. 

 These are the neptunian representatives of the Asturian and Armorican 

 types. In like manner the herring, the cod, the pollack, abound only 

 in the North sea, along the eastern coast, where the Germanic type is 

 predominant. Finally, the great Cetacea, such as whales, narwals, 

 and dolphins of the Arctic seas, seem even in the depths of the ocean 

 to respect the ideal limit which separates the boreal vegetation of 

 Scotland and of England from the more southerly floras of Cornwall 

 and the south of Ireland. 



Till the present time naturalists had seen in this distribution of 

 organized beings, with reference to certain definite regions, but a 

 natural consequence of the all-powerful influences of climate and of 

 soil. If some plants of the Asturias maintain themselves in the south 

 of Ireland, it was thought a sufficient explanation that tlicy find there 

 the temperate winters of tlie Iberian peninsula, while the moderate 

 heat of the Irish summer suffices for the ripening of their seed. For 

 a like reason the plants of Brittany and Normandy have established 

 themselves in Cornwall and Devonshire, where a climate prevails 

 analogous to that of their own country. The robust growths of Ger- 

 many had found in the middle region of England, in the south of 



