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Upon a minute examination of its external surface, a spongeous, or 

 rather porous structure, is discoverable : some of the pores appearing 

 to be the result of a peculiar reticulated texture ; whilst others, of ra- 

 ther an oval form, may be supposed to be the openings of the rami- 

 fying tubuli, already noticed. The examination of its internal sur- 

 face is prevented by a friable matter, which appears to be partly cal- 

 careous and partly silicious, with which its cavity is nearly filled. A 

 portion of the posterior part is covered with this same matter, which 

 seems to have invested the whole fossil, and appears rather to have been 

 a covering peculiar to the animal, than merely the matrix in which it 

 had lain. This fossil resembles, in its composition, several of the French 

 and Swiss alcyonic fossils, already mentioned, in being an intermix- 

 ture of silicious and calcareous earth : the former having possessed 

 the animal substance itself, and the latter the interstices. 



Small fragments of this kind of fossil had been long discovered, 

 whilst digging or ploughing in the Vale of Pewsey : but their forms 

 were so indeterminate and various, as to have led to the most vague 

 and fanciful conjectures respecting their original nature. By some 

 they were imagined to be portions of petrified wood, and by others 

 to be fragments of bones ; but Mr. Townsend, who had met with 

 them in his own garden, collected numerous specimens, and in conse- 

 quence of his extensive knowledge in natural history, soon ascertained 

 their origin, and determined, that they were the mineralised remains of 

 some zoophyte of the former world. 



According to Mr. Townsend's obliging information, these remains of 

 zoophytes are found immediately under the chalk, in a dark green sili- 

 cious sand, which contains many prism of quartz crystals; the colour 

 being; derived from the intermixture of an oxide of iron. In the same 



o 



green sand, nautilites are found of a loot or fourteen inches diameter; 

 and on digging deeper, similar bodies to those existing in the green 

 sand are found, approaching to an agatized state. 



The farther I advance in my labours, the more reason I find for con- 



