447 



rounded by attrition, being a fragment of silicious wood. It was 

 found in the gravel- pits at Hackney. 



Fig, 15 and 17> in Plate VI. represent two specimens of a sub- 

 stance which is sometimes found in the chalk-pits at Cherry Hinton, 

 in Cambridgeshire. They have been supposed to approach very 

 near in resemblance to the juli of the larch-tree ; from which they 

 differ, however, so much in some respects, as to have induced 

 Dr. Parsons to have considered them, rather as the roots of a 

 plant, than the parts of fructification. The appearance which they 

 exhibit does, however, certainly support the opinion of their having 

 been either aments, or cones, of some tree not now known, at least, 

 to the European botanist ; whilst, on the other hand, the situation 

 in which they are found, renders this highly problematical. Instead 

 of being found associated with other fossil vegetables, or in matrices 

 which have originated in the decomposition of vegetable matter, 

 they have, I believe, only been found in chalk, which has proceeded 

 chiefly from aqueous deposition, and in part from the decomposi- 

 tion of animal, but certainly not of vegetable matter. 



The other fossil remains of fruits on this Plate are all from that 

 fruitful mine of fossils, the Isle of Sheppey : and, in common with 

 most of the fossils obtained from this part, have so much pyrites 

 enter into their composition, as renders their stay in the cabinet of the 

 collector, in general, but very short, from their proneness to decom- 

 pose after having been exposed to the air. This has been the case 

 with the specimen represented at Fig. 5 and 7> which had evidently 

 been the stone of some drupaceous fruit, and which was so com- 

 pletely pyritous, that, .on being cut, the polished section, repre- 

 sented Fig. 7, shone with the most brilliant golden lustre; the 

 traces of its texture not being discoverable without the aid of a 

 lens of considerable power. Of the remaining specimens, I regret 

 that, although favoured by the assistance of the distinguished 

 botanist already mentioned, and by several other gentlemen emi- 



