232 VEGETABLE COLONIZATION. 



Scotland, and the north of Ireland conditions of existence analogous 

 to those of the north of Germany and of France, and hence their 

 multiplication and diffusion through the larger portion of the British 

 islands. Lastly, the crags, the heathy acclivities, the peat-mosses 

 and moors of Scotland, afforded to Arctic plants the diversified sta- 

 tions, the summers without excess of heat, the long vs^inter slumbers, 

 and the protecting snows of polar regions. 



Mr. Edward Forbes could not content himself with these explana- 

 tions ; he discerned a deeper meaning in the existence of those foreign 

 types which constitute the fauna and flora of the British islands. To 

 him they seemed to present vestiges of an order of things which has 

 passed away ; proofs of the existence of climates warmer or colder 

 than those now prevailing ; signs of a configuration of land and sea 

 whose traces lie hidden in the depths of ocean. We may be per- 

 mitted to follow him in his ingenious and learned researches. Pene- 

 trating first into this new path, he may, he must have often gone 

 astray. But with a powerful grasp he re-unites the past and present 

 of our globe, he summons every realm of nature to the support of his 

 ideas, and even though he may be mistaken, he will not the less 

 have contributed to the progress of the natural sciences by com- 

 mencing the overthrow of that imaginary barrier which scientific 

 inquirers as well as tradition have reared between the actual state 

 and the geologic epochs of our planet. 



The dozen plants from the Asturias, which inhabit the southwest 

 of Ireland, are in the eyes of Mr. Forbes the remains of the most 

 ancient vegetable colony of the British isles. Of all the plants they 

 now sustain none are more completely strangers to the soil which 

 bears them. The remoteness of the continental point of departure, 

 the vast gulf which separates the little colony from its mother coun- 

 try, the difference of climates, the small number of surviving species, 

 all announce an ancient origin and an order of things entirely differ- 

 ent from that now existing. Mr. Forbes, ascending through the 

 series of geologic formations, transports us to an epoch when the last 

 tertiary deposits were formed at the bottom of a sea which covered a 

 great part of the south of Europe and the north of Africa.- The ex- 

 istence of that sea is proved by the numerous fossil shells of identical 

 species which are found at a multitude of points from the isles of 

 Greece to the southern districts of France. Wlien these newly formed 

 lands lifted themselves above the sea they formed a vast continent, 

 embracing Spain, Ireland, a part of the north of Africa, the Azores, 

 and the Canaries. 



The upheaving of the bottom of that sea is not a gratuitous hypo- 

 thesis, since Mr. Forbes has found these same shells in the Taurus, at 

 the height of 6,000 feet above the level of the Mediterranean. Yet more : 

 the vast bank of floating algro which extends in a half circle beyond 

 the Azores from the fifteenth degree to the forty-fifth degree of lati- 

 tude, Retraces for us, perhaps, the outline of that lost continent. Its 

 shores have disappeared beneath the sea, but the cincture of marine 

 plants which girdled it still floats on the surface of the waters.* 



« This bank is composed of a species of algaj, the Sargassum bacciferum, which appears to 

 be only a floating variety of the Sargassum vulgare, which is found attached to submarine 

 rocks bordering the coasts of Europe. 



