46 M. Martins on the Vegetable Colonisation of the 



According to Mr Forbes, the appearance of Armorican 

 plants in Devonshire, Cornwall, and the south-east of Ire- 

 land, is connected with the existence of this destroyed conti- 

 nent. The southern physiognomy of these vegetables is, in 

 his view, the indication of a more temperate climate than 

 the present. At the same time, there is nothing to prevent 

 us regarding this migration as contemporaneous with the 

 Germanic invasion, referring it to the epoch when England 

 and France were still united. 



The immersion of this great continent was followed by a 

 period completely different, during which the temperature of 

 the air was lower than it now is. It was during this period, 

 according to Mr Forbes, that the migration of the arctic 

 plants which have maintained their position in the mountains 

 of England and Scotland, took place. The proofs of a gla- 

 cial period immediately preceding that in which we live, 

 abound throughout the whole north of Europe. 



I shall not speak, in this place, of the numerous traces of 

 ancient glaciers found in the mountains of Scotland, England, 

 and Ireland, but confine myself to the arguments derived 

 from the animal kingdom.* 



The greater part of the British Islands is covered with a 

 moveable formation composed of transported materials, which 

 English geologists call drift. In the northern two-thirds of 

 England and Ireland, and in all Scotland, this drift contains 

 the remains of animals nolonger found in a living state, except 

 in the bosom of the Icy Sea, on the coasts of Iceland and 

 Greenland. The enumeration of these would be tedious. I 

 shall merely mention the Balwna mysticetus, the large- 

 headed cachalot, a baleinopteron, the narwhal, a cetacea of the 

 Greenland seas, and a great number of shells, which still 

 exist in the same latitudes. During this period, England 

 was, therefore, partly covered by waters whose temperature 

 approached to that of the Icy Sea. Not only the plains, but 

 also all the lower parts of the mountains, formed the bottom 



appears to be only a floating variety of Sargassum vulgare, which is found 

 fixed to the submarine rocks which border the coasts of Europe. 



* See on this subject, Researches on the Glaciary Period and Ancient Exten- 

 sion of the Glaciers of Mont Blanc, from the Alps to the Jura, Reveu des Deux 

 Mondes, vol. xvii., p. 919, 1st March 1847. 



