126 MA UN A LOA. 



level and smooth, it is seen to be covered with large pieces of lava, 

 rising in places into cones thirty or forty feet high, which are appa- 

 rently bound down by huge tortuous masses, which surround them like 

 cables. In other places these are stretched lengthwise on the level 

 ledge, and look like hideous fiery serpents with black vitreous scales, 

 that occasionally give out smoke, and in some cases fire. 



The immense space which I have described the crater as covering, 

 is gradually filled with the fluid mass of lava to a certain point, above 

 which the walls, or the surrounding soil, are no longer able to bear the 

 pressure, it then finds vent by an eruption, previous to which, how- 

 ever, a large part that is next to the walls of the crater has in a measure 

 become cooled, and remains fixed at the level it had attained. After 

 the eruption, the central mass therefore alone subsides three or four 

 hundred feet, and leaves the portion that has become solid, forming a 

 kind of terrace or shelf: this is what constitutes the " black ledge," 

 and is one of the most striking features of the crater. Its surface is 

 comparatively level, though somewhat uneven, and is generally coated 

 with a vitreous and in some places a scoriaceous lava, from half an 

 inch to an inch thick, very iridescent and brittle. In walking over 

 this crust, it crumbles and cracks under the feet; it seems to be easily 

 decomposed, and in some places had lost its lustre, having acquired a 

 grayish colour and become friable. There was another variety of the 

 vitreous lava, which was smooth and brittle: this occurred in the large 

 hollow tunnels or trenches, the insides of which were rough, and full 

 of sharp and vitreous points. On the turnings and windings small 

 swellings were met, which on being broken off, had a strong resem- 

 blance to the bottom of a junk-bottle ; at another place, fragments 

 appeared to have been scattered around in a semi-fluid state, in an 

 endless variety of shapes, and so brittle as to be preserved with diffi- 

 culty. Underneath these was to be seen the real lava or basalt, as 

 firm and solid as granite, with no appearance of cells, and extremely 

 compact; it is seen separated into large blocks, but none that I saw 

 were of a regular figure, though in some places it was thought by 

 others to approach the hexagonal form. 



There is a third kind of lava, fibrous in its texture, of quite recent 

 ejection, and procured from the bottom of the crater ; this had some- 

 what the appearance of a dark pumice, but was dense in comparison. 

 On the black ledge the absence of all debris from those high perpen- 

 dicular walls, cannot fail to be remarked ; we endeavoured to find an 

 explanation of this, but I was not satisfied with the only one which 

 presented itself. This was to suppose that the fluid mass had recently 

 risen above the ledge, altogether concealing it from view, and that it 



