VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 345 



frequently meet with on belemnitae, when the animal within was perhaps either 

 waxed old, or was dead ; and is an additional proof that the body is of marine 

 origin. 



Every one, who has made this part of natural history his study, must have 

 observed, that the minutiae, or exceedingly small fossil shells, very frequently 

 occur, and in the greatest abundance, especially in fine loam or clay proper to 

 presei-ve them : which shows that it was spring or spawning-time when the de- 

 luge overwhelmed the country they were natives of. And that diminishes one of 

 the difficulties concerning the belemnites, why some have the cavity, others not, 

 or but very small : for may we not attribute these several appearances to the dif- 

 ferent ages of the animal ; as in the spring or spawning-time, and some time 

 after, a thousand small fish appear in the water to one grown to maturity, or 

 seedlings on the shores of shell-fish, to one at full growth ? and, from a parity 

 of reasoning, is there not great likelihood to believe that every belemnites would 

 have had a nucleus, if it had lived ; and to suppose that deficiency to be caused 

 by the deluge coming on, in the early part of the season, in that spot where 

 they are natives, before they had attained perfection ? 



The country of the belemnitae is unknown to us ; but there is great probability 

 it is the same with that of the conchae anomiae in general, and ammonitae; since 

 they are usually found together, and are well supposed to be the inhabitants of 

 deep or unknown seas, beyond human reach. 



Having had so frequent occasion to mention the orthoceratitae in the course of 

 this subject, they being here rare and uncommon fossils, Mr. B. has given the 

 figures of some (ew species of them, which perhaps may not be unacceptable, 

 N" 6, 7, 8, 9, 1 6. If it should be asked, whether they proceed likewise from 

 a belemnites ? he answers, that he supposes them to proceed from a polype like 

 the rest, but whether their parent polype formed itself a belemnites-like chrysalis 

 or habitation, being a stouter animal, is more than he can affirm, though very 

 probable, as the terminating point in them is as sharp and fine as the nucleus of 

 the belemnites ; and it is observed, that all the turbinated shells increase their 

 circumvolutions from the point or apex ; but that is not the immediate business 

 of the present purpose, as nature has many ways to compass her ends. His de- 

 sign will be answered, if it shall only be thought, that he has evinced the be- 

 lemnites to be an animal production, formed by a polype, as other coralline 

 bodies ; and its nucleus to be a concamerated testaceous bcxly, of the nautili 

 genus, proceeding from it. 



Description of the Plate 14. 



Fig. 5. A section of a common nautilus. 6, 7, 9. l6, Sections of ortho- 

 ceratitae. 8. An orthoceratites entire. 10. A section of a belemnites, with the 

 nucleus. 11. Ditto, without the nucleus. 12. An oblique section of a belem- 



VOL. X, 4 A 



