British Islands, Shetland^ Feroe, and Iceland. 4^7 



or shore of this ocean ; for beds of gravel, sand, and shells 

 have been found in Wales, at a height of about 450 metres 

 above the level of the present sea. At this period, England 

 and Scotland did not form a continuous land, but a group of 

 islands and islets. The mountains of Scotland, Cumber- 

 land, and Wales, alone rose above the waves. A climate 

 analogous to that of Iceland reigned over this archipelago ; 

 the summits of the mountains were covered with eternal 

 snow like that of Hecla, and numerous glaciers descended 

 the valleys to the edge of the sea. The plants of Greenland, 

 Iceland, and Norway, carried by the currents, or transported 

 by the floating ice, were thrown upon these islands, where 

 they found a climate scarcely different from that of their na- 

 tive land. This transportation of plants by floating ice, is 

 not a gratuitous hypothesis. The navigators of the Polar 

 Seas have often met with icebergs, bearing an enormous mass 

 of debris mingled with earth and gravel. Plants grow on these 

 debris as among the median moraines of the glaciers of the 

 Alps ; and the iceberg grounding on some distant shore, 

 there deposits, so to speak, the plants, which afterwards spread 

 over the country. 



These arctic plants, says Mr Forbes, have not disappeared 

 from England. They still exist among the mountains of 

 Cumberland, in Wales, and especially in Scotland, where 

 they find a climate analogous to that of their native country. 



At the end of the glacial period, the British Islands be- 

 gan to rise slowly from the bosom of the waves. We still 

 find, everywhere along the coasts, terraces or lines of ancient 

 beaches, indications of the periods of repose which interrupted 

 this gradual elevation. In order to understand this pheno- 

 menon aright, we must imagine not a simple elevation of the 

 coasts, the submarine parts remaining immoveable, but the 

 simultaneous rising of the bottom of the sea and the lands 

 together, above their ancient level. It is this upheaving 

 which has modelled the present relief of the British Islands, 

 and determined the configuration and depth of the surround- 

 ing seas. The depressions have been rendered less deep, 

 and the high bottoms have been brought above the waters. 

 Hence, a change in the maritime fauna. The sea being 

 warmer, its coasts were occupied by the animals which now 



