MAURITIUS. 327 



high mountains which abound in the ishind. Tlie 

 north and south of Iceland present an aspect tho- 

 roughly characteristic of these facts, ^^'e there find 

 immense plateaux, whose submarine origin is plainly 

 indicate 1 by alternate beds of basalt and basaltic 

 conglomerate. 



The Isle of France (Mauritius) has all the cha- 

 racters of a submarine volcanic ibrmation, which has 

 been elevated en masse subsequently to the cessation 

 of the eruptions. Bourbon, the near neighbour of 

 Mauritius, presents, on the contrary, the appear- 

 ance of the ordinary volcano, formed by the repeated 

 coolings of lava-streams flowing from two or three 

 sources constantly above the level of the sea, and one 

 of which is in incessant activity. 



Allowing, however, that the remarks of Mr, Poulett 

 Soroi e are well-lbundel, it must be owned that they 

 are subject to numerous exceptions. The remark- 

 able investigations of M. S .inte-Claire Deville have, 

 in fact, demonstrated that the nature of volcanic pro- 

 ducts vj ries ;ii( ording to the length of time that the 

 volcano has been in activity. It would lead us too 

 far from our special subject to discuss this interesting 

 question, but we may indicate in a very few words 

 one of the many results obtained by M. Deville. A 

 volcano seems to have its [)eriod of youth anl its 

 p( rio I of oki age. During the first period, luvjis are 



