IN THE MUD OF THE LEVANT. 93 



the mud from Charlestown harbour, U.S. which, 

 as has been already noticed by Dr. Bailey, 

 contains detached rhombohedra of carbonate of 

 lime, so perfect as to leave little doubt but that 

 they are the direct result of some chemical action, 

 and are not derived from the recent destruction of 

 calcareous organisms. I was interested on finding 

 similar crystals amongst Foraminifera, brought up 

 from an Artesian well sunk at Charleston, at a 

 depth of near two hundred feet ; so that those in 

 mud may be derived from the older deposit, with 

 which the stream may come in contact in some 

 part of its course. The existence of Foraminifera 

 in the recent esturian mud renders this some- 

 what probable ; but, on the other hand, in the 

 latter instance, the rhombohedra are so much more 

 numerous than the Polythalamia, as compared 

 with their relative proportions in the borings from 

 the Artesian well, that, if they have been so 

 derived, it has been from some portions of the 

 stratum where the crystals were much more 

 abundant than at Charlestown. At the island of 

 Ascension, Mr. Darwin found that the sands on 

 the beach had been consolidated by calcareous 

 matter deposited from the sea water, in which it 

 was held in solution. The calcareous matter 



