332 POPULAR GEOGRAPHY OP PLANTS. 



ably proved by the remains of the marine animals found in 

 the strata deposited in that sea." 



Having thus accounted for the Alpine flora, we must next 

 conceive that, in the course of time, the bed of this great 

 glacial sea was upheaved, till at last, that which before had 

 been sea, became dry land. The islands were by this pro- 

 cess connected with each other, and converted into moun- 

 tains ; and the plants of a sub-arctic character, which before 

 had been growing at the water's edge, now found themselves 

 on the tops of these mountains. It is over the land thus 

 formed that the plants of the Germanic flora (from central 

 and western Europe) are now supposed to have migrated ; 

 which is thus proved to be of more recent date than the 

 mountain flora. 



It will be remembered that of the two floras which cha- 

 racterize, one of them the south-east of England, and the 

 other the south-west of England and the south-east of Ire- 

 land, the first is said to have had its origin in the opposite 

 coast of Prance, and the other in the Channel Islands and 

 neighbouring coast of France. Their arrival is very simply 

 accounted for by a theory, the truth of which " no geologist 

 doubts," according to which the two sides of the English 

 Channel were anciently united ; and, as the south of Eng- 



