172 



ISLAND LIFE. 



[pvVRT I. 



angular blocks of serpentine and greenstone often of enormous 

 size, one being fourteen feet long, and another twenty-six feet. 

 Some of the blocks were observed by Sir Charles Lyell to be 

 faintly striated and partly polished on one side, and they are 

 scattered through the beds for a thickness of nearly 150 feet. 

 It is interesting that the particular bed in which the blocks occur 

 yields no organic remains, though these are plentiful both in 

 the underlying and overlying beds, as if the cold of the icebergs 

 had driven away the organisms adapted to live only in a com- 

 paratively warm sea. Rock similar in kind to these erratics 

 occurs about twenty miles distant in the Alps. 



The Eocene period is even more characteristically tropical in 

 its flora and fauna, since palms and Cycadacese, turtles, snakes^ 

 and crocodiles then inhabited England. Yet on the north side 

 of the Alps, extending from Switzerland to Vienna, and also 

 south of the Alps near Genoa, there is a deposit of finely- 

 stratified sandstone several thousand feet in thickness, quite 

 destitute of organic remains, but containing in several places 

 in Switzerland enormous blocks either angular or partly rounded, 

 and composed of oolitic limestone or of granite. Near the Lake 

 of Thun some of the granite blocks found in this deposit are of 

 enormous size, one of them being 105 feet long, ninety feet wide, 

 and forty-five feet thick! The granite is red, and of a peculiar 

 kind which cannot be matched anywhere in the Alps, or indeed 

 elsewhere. Similar erratics have also been found in beds of the 

 same age in the Carpathians and in the Apennines, indicating 

 probably an extensive inland European sea into which glaciers 

 desQended from the surrounding mountains, depositing these 

 erratics, and cooling the water so as to destroy the mollusca 

 and other organisms which had previously inhabited it. It is 

 to be observed that wherever these erratics occur they are 

 always in the vicinity of great mountain ranges ; and although 

 these can be proved to have been in great part elevated during 

 the Tertiary period, we must also remember that they must 

 have been since very much lowered by denudation, of the 

 amount of which, the enormously thick Eocene and Miocene 

 beds now forming portions of them is in some degree a measure 

 as well as a proof. It is not therefore at all improbable that 



