84 Geology of Antigua. 



conclusive evidence, that the two classes of rocks were formed 

 under different circumstances. All the chert beds do not, indeed, 

 contain shells ; but as they are not found in miy of the strata of 

 the other formation, they seem to indicate a palpable line of dis- 

 tinction between the two. 



If then we refer the chert and the petrifactions connected with 

 it to a silicious solution, we may still inquire from what source 

 such a solution could have been derived. It is well known, that 

 pure silicious deposits from hot springs are not uncommon, and 

 that such springs abound in volcanic countries. The Geysers of 

 Iceland are striking examples of this kind. And though Antigua 

 is not at present a volcanic island, it presents the most manifest 

 exhibitions of igneous agency at no very remote period. These 

 silicious deposits and immense fossil transformations may have 

 taken place at that time, either from subaqueous springs charged 

 with silex, or large bodies of water thrown up from the bowels of 

 the earth, and spread out on the surface in the form of basins. 

 The low position of the part of the island where these beds 

 abound, would perhaps favor this supposition. I am, indeed, 

 aware that the subject of silicious solutions is yet involved in 

 great mystery — the process by which nature dissolves silica 

 having yet in a great measure evaded the scrutinizing eye of sci- 

 ence — but the fact is among the best ascertained phenomena of 

 geology, and may therefore be employed in the explanation of 

 those deposits, which other circumstances would naturally refer 

 to such an origin. 



I cannot but regard the fact, that minute fibres of the roots of 

 trees, and tender leaves and fruits, which must certainly have 

 been destroyed by the least degree of violence, are found among 

 the fossils, as furnishing additional evidence, that the lapidifying 

 process took place in a silicious solution. It does not appear pos- 

 sible, that any great degree of heat should have existed in the su- 

 perficial strata of the earth, without having destroyed every thing 

 on the surface in the form of woody fibre. 



But there is another class of silicious fossils, found in the cal- 

 careous formation, at a distance of several miles from the chert 

 deposits, which cannot be explained upon any of the preceding 

 hypotheses. They are the silicified shells and corallines, which 

 I have already described as occurring both upon the surface of the 

 earth and in lower strata. The corallines, especially, are so per- 



