218 GLIMPSES OF NATURE. 



cally, part and parcel of a bigger tract of land. They 

 are the separated and disjointed fragments, so to speak, 

 of a larger land-mass. Under this head are to be 

 included many islands we know. The British Islands 

 are simply detached parts of the European Continent ; 

 just as Trinidad is a fragment of South America ; or 

 as the Malay Archipelago represents the broken-up 

 land which, once upon a time in its hale and solid state, 

 connected Asia and Australia. Even New Zealand 

 and Madagascar are continental islands in their way, 

 although the exact dates of their separation may be 

 very hard to trace in the mists of geological time. 



Having thus succeeded in distinguishing between 

 islands which, like St. Helena, the Azores, the Gala- 

 pagos, and so forth, represent the eruptions into the 

 earth's outside mass of volcanic matter, and those 

 which, like Britain, Trinidad, and the West Indies, 

 are really the detached pieces of large land-tracts, it 

 behoves us to inquire further into the history of each 

 group. We find the sea around our volcanic islands 

 of great depth. They are separated from their main- 

 lands, it may be, by abysses of ocean. On the other 

 hand, the continental islands have, relatively, shallow 

 seas separating them from their nearest continents. 



Witness, in proof of this statement, the German 

 Ocean, the English Channel, the sea between Trinidad 

 and America, or the general depth of the seas around 

 the Malayan Islands. We find a test, not only of the 

 nature of an island in the depth of the seas around it 

 apart from its rock-structure but, in the case of 

 the continental islands, we can assure ourselves of the 

 length of time they have been separated from their 

 mainlands, by having regard to the same matter of 

 ocean-deepness. The Azores, as volcanic islands, are 



