VOL. LIV.] PHILOSOPHICAL TRANSACTIONS. 97 



walls, both in length and thickness, from the cell or chamber, to the bottom or 

 point of the whole belemnite. The animal, in its progress and return, clasps 

 the whole guard, as a snail does a small branch of a tree in the gardens ; and 

 where the two sides meet, there the sulcus is formed, as is evident from the 

 laminae in fig. 9- 



The belemnites, like all other testaceous bodies, have the vermicular tribe at- 

 tached to them, and are perforated by the pholades. Other marine bodies also 

 affix themselves to the belemnites, oysters in particular : but this never happens 

 while the animal inhabits the shell, because the new additional laminae would so 

 cover the affixed body, and also the cells of the pholades and vermiculi, that 

 they could have no communication with the water, and must consequently 

 perish. These bodies, thus attached, are the strongest proof we can desire, that 

 the belemnite is of marine production. Indeed it may be objected, that the 

 bones of quadrupeds, wood, and stone have these bodies adhering to them, and 

 therefore may be said to be marine as well as the belemnite. But when we 

 bring them to chemical trial the objection vanishes; for the bones either come 

 out of the furnace with a black core, or they are reduced to ashes; whereas the 

 belemnite is changed into a fine calx, after the manner of all testaceous bodies, 

 and is converted into a species of phosphorus.* The oysters, having no loco- 

 motion, frequently affix themselves to other bodies, that they may be better able 

 to stem the tides and currents which might otherwise carry them from their 

 proper bals and places of feeding. This attachment to other bodies no way in- 

 commodes them, because they increase the dimensions of their shells by adding 

 fresh laminae inwardly: the first formed laminae being as it were excluded, lie in 

 the manner of tiles upon the roof of a house, and exhibit the several steps or 

 stages of their growth. 



Mr. P. believes a belemnite is very rarely found perfect in the fossil state: 

 those in gravel-beds (fig. 15) have suffered very much by being rubbed against 

 stones, &c. by the fluctuating waters: those which we find in rubble at Gar- 

 sington pits (fig. 1 6) have many adventitious bodies adhering to them, and con- 

 sequently were deserted by their inhabitants before they rested there. In the 

 clay at Shotover (fig. 1) near Oxford, they have a curious smooth surface, but 

 are otherwise imperfect: at Stonsfield, in the slate-stone, they are generally 

 crushed (fig. 2, y): those approaching nearest to perfection, which he had seen, 

 came out of the sand (fig. 13) under the bed of stone at Garsington-pits near 

 Oxford: the outer part is quite perfect, and the verge of the conical cavity is as 



• The belemnite after calcination has all the properties of the Bolognian stone. If it be exposed a 

 few minutes to the sun, and immediately taken into a dark room, it will shine like phosphorus for 

 some time; and when the light diminishes, if again exposed to the sun, its splendor will be re- 

 newed. — Orig. 



VOL- XII. O 



