PHYSIOGNOMY OF PLANTS. 11 



ancient civilisation causes the forests to recede more and 

 more, and that the wants and restless activity of large com- 

 munities of men gradually despoil the face of the earth of 

 the refreshing shades which still rejoice the eye in Northern 

 and Middle Europe, and which, even more than any historic 

 documents, prove the recent date and youthful age of our 

 civilization. The great catastrophe which occasioned the 

 formation of the Mediterranean, when the swollen waters 

 of what was previously an immense lake burst through 

 the barriers of the Dardanelles and of the Pillars of 

 Hercules, appears to have stripped the adjacent countries of 

 a large portion of their coating of vegetable mould. The 

 traditions of Samothrace, ( 8 ) handed down to us by Grecian 

 writers, appear to indicate the recentness of the epoch of the 

 ravages caused by this great change. In all the countries 

 which surround the Mediterranean, and which are charac- 

 terised by beds of the tertiary , and cretaceous periods 

 (nummulitic limestone and neocomian rocks), great part 

 of the surface of the earth consists of naked rock. One 

 especial cause of the picturesque beauty of Italian scenery 

 is the contrast thus afforded between the bare rock, and 

 the islands if I may so call them of luxuriant vegeta- 

 tion scattered over its surface. Wherever the rock is 

 less intersected with fissures, so that it retains water at 

 the surface, and where it is covered with vegetable mould, 

 there, as on the enchanting shores of the Lake of Albano, 

 Italy has her oak forests, with glades as deeply embowered 

 and verdure as fresh as those which we admire in the North 

 of Europe. 



