846 Mr. Parkinson on the Strata^ 



been seen in our English chalk. But research has not been made 

 with the necessary precision. 



Three Vermicul'ites. The fossil figured Org. Rem, vol. III. pi. 

 VII. fig. 11, was considered as a vermiculite, until by removal of the 

 chalk and opening different specimens it was found to be a cham- 

 bered and an adherent shell. Should these gentlemen not have per- 

 ceived these circumstances in the specimens they met with, they 

 would certainly regard this fossil as a vermiculite. It must also be 

 observed that from the different forms in which the spiral part is 

 disposed, its division into two or three species might be authorised. 



Bekmnites. These, according to M. De France, are different from 

 those which accompany the ammonites of the compact limestone. 

 The bekmnites of our chalk are smaller than those of the limestone, 

 besides which they are different in form, being narrower and more 

 elongated. But M. De France may also have confounded with them 

 the spines of the echinus^ which so closely resemble the helemnite: if 

 that gentleman should not have met with perfect specimens, he might 

 not be able to remark the difference between these two fossils. The 

 characters which he has noticed are however sufficient to lead to the 

 belief of a correspondence between the French and English fossils. 



Fragments of a thick shell of a fibrous structure. The doubts ex- 

 pressed respecting the nature of this shell, and the observations made 

 with regard to it, offer another strong point of agreement between 

 the shells of the two strata. The shell here alluded to is most pro- 

 bably that represented Org. Rem. vol. III. pi. V. fig. 3 ; the structure 

 of which agrees exactly with that mentioned as found in the French 

 stratum of chalk. That shell is however described as being of a tubular 

 form ; it is therefore right to observe, that fossil pinna do sometimes 

 possess this peculiar structure. 



