AND STRUCTURE OF THE BELEMNITE. 413 



ties, which are rounded off. These are very like the perfo- 

 rations of a worm, and have induced me to believe, that 

 many of them are merely casts of flint, in cavities formed 

 in that manner. 



Nos. 7, 8, and 9. In these specimens the flint which has been 

 displayed by the dissolution of the calcareous spar, presents 

 a new appearance, which may perhaps be best compared to 

 the ovarium of some animal. Small roundish masses are 

 connected and entangled with each other by thin and very 

 delicate threads. 



No. 10. Is one of the globular masses * larger than usual, but 

 also a little magnified in the drawing. I should observe, that 

 the flint in most of these fossils approaches to calcedony, and 

 is lighter in its colour than the general mass. It sometimes 

 presents an opake chalky-looking aspect, which, I presume, 

 arises from an admixture of calcareous matter, for I have 

 found this variety very liable to crumble into dust, after the 

 operation of the acid. 



No. 11. Is the same fossil found in the limestone, and by be- 

 ing broken longitudinally, there appear in the section of it 

 cavities filled with chalk, as they would have been filled 

 with flint in the specimens I have described. I have a great 

 many more of the same kind, particularly of the flints, and 

 some of them presenting the most beautiful arborisations I 

 ever saw, quite similar to the most delicate sea-weed, which 

 had apparently been attached to the outer surface of the be- 

 lemnite. 



This 



** In specimens of this kind, I have noticed that the connection between these 

 globular masses, is maintained, more particularly by too fibres, larger than the 

 others, and more uniform in their position. 



