402 



Appendix. 



posed similar origin. The internal crater on the left hand side of 

 Fig. 2, which presents the most striking manifestation of this dis- 

 position, has been obliterated in the sketch contained in the Journal 



Fis:. 1. 



of the Royal Geographical Society, and occupied by smoke and a 

 prodigious flash of lightning. 



There is every reason to believe that volcanic eruptions take place 

 at the bottom of the sea, in the same manner as on the surface of a 

 continent ; and Mr. Osborne points out the fact that, in the elevated 

 sides of the external ridge of the island, the sides fall dovin in abrupt 

 precipices ; and each stratum could be distinctly discerned, the water 

 evaporating having left an incrustation of salt, which now appears a 

 white firm layer, plainly marking the regular progress and formation 

 of the island. It is very evident that this kind of action and succes- 

 sion could not have taken place above the level of the waters either 

 of the sea or of the internal crater ; as it further demonstrates that 

 horizontal beds of volcanic matters, accumulated over each other, 

 can be directed on a given point without any violent contortion or de- 

 rangement of their symmetry and parallelism. Nor have we, in the 

 present case, any invasion of the sea or explosions posterior to (he 

 formation of the cone, if we may judge from the details transmitted 



