206 



different from any shells of the present age. This is taken 

 from another specimen which also came from Bath by fa- 

 vour of T. Walforu, Esq. The pyrites on this are octae- 

 drons, some of which have their solid angles slightly trun- 

 cated. It nearest resembles Trochus niloticus Linn., but 

 we do not consider it as that species. 



The cast of the shell on the right hand, of a golden hue., 

 being covered with pyrites, generally deeply truncated, 

 seems a species of Mytilus cut off in the manner of Donax 

 denticidata Linn. The shell on the left hand seems to be 

 a Tellina, and includes pyrites, chiefly of a cubo-octaedral 

 form — see left hand bottom figure — as it were hermetically 

 sealed in, and of course not discovered till the shell was 

 broken. How these crystals came there may excite 

 wonder ; but, were we sufficiently acquainted with nature's 

 operations, we should see every natural cause as well as its 

 effect. This shell most nearly resembles Lister's Tellina 

 lata rngosa, tab. 390.fi 229. 



These fossils are in great abundance above the sand 

 quarries at Woolwich and Charlton, about nine feet from 

 the surface of the hill, in a loose marly stratum, from one 

 to six feet thick. 



How long they have been preserved there is not known ; 

 they however will soon rot and decay after exposure to the 

 air. The other sorts of shells are two species of Turbo, 

 probably of the same date; these will also fall to pieces. 

 Of oyster shells there is great abundance, which do not, to 

 my knowledge, differ from those at present known, nor do 

 they decay so readily as the others. There are other shells 

 in this curious place, and in Lady Wilson's park at Charl- 

 ton, with specimens of which I have been favoured by her 

 ladyship. I have gathered the more common ones myself, 

 3 



