548 



Notice of tJie Volcanic Island 



fact that, in the elevated sides of the external ridge of the 

 island, the sides fall down 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 form- 

 ation of the island. It is very evident that this kind of action 

 and succession 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 derangement of their sym- 

 metry and parallelism. Nor have we, in the present case, any 

 invasion of the sea or explosions posterior to the formation 

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

 us of the elevation and appearance of the island, to account 

 for the well characterised circus or mural precipice which 

 surrounds the canal of communication or crater of eruption. 

 It does not farther appear, from the soundings, that this 

 island is the summit of a cone of eruption with an open 

 crater. Captain Swinburne found, within 20 yards on the 

 western side, 18 fathoms soft bottom ; and Capt. Smith found, 



