248 PERMIAN FOSSILS. 



Ammonites, Sedgwick, p. 219. 



Professor Sedgwick states, that " a cast of a small Ammonite was found among the Humbleton fossils" 

 (Trans. Geol. Soc. London, 2d series, vol. iii, p. 118). I have often suspected the cast alluded to, to 

 be a specimen of Nautilus Freieslebeni ; but I am prevented offering a positive opinion on this point, 

 in consequence of Professor Sedgwick having stated in his 'Anniversary Address to the Geological Society,' 

 for 1829, that "the only Ammonite I have ever found in the Magnesian limestone, had those suture-like 

 markings which distinguish this genus in the upper secondary rocks." (Proceedings of the Geological 

 Society, vol. i, p, 284.) Unfortunately, the specimen has been mislaid ; but Professor Sedgwick informs me, 

 that he still thinks, it had plates with uneven margins, and might, therefore, belong to the genus Ceratites, 

 which is probable enough, considering, that species of this group occur in the more recent rocks of 

 St. Kassian. 



