AMMONITES — ZOOLOGICAL, ETC. 



315 



AMMONITES. AMMONITES. 



Ferandianus, d'Orb. Renauxianus, d'Orb. 



Flmriansianus, d'Orb, Requienianus, d'Orb. 



Goupilianus, d'Orb. Rhotomagensis, Defrance. 



Lafresnayeanus, d'Orb. Rusticus, Sow. 



Largilliertianus, d'Orb. Sartousianus, d'Orb. ■ 



LewesiensiSy Soiv. Tricarinatus, d'Orb. 



Mantellii, Sow. Varians, Sow. 



Pailletteanus, d'Orb. Feneuilianus, d'Orb. 



Papalis, d'Orb, Vibrayeanus, dOrb. 



Peramplus, Sow. Woolgari, Sow. 



Prosperianus, d'Orb. 



Although the whole of the species cannot be divided into 

 epochs, I may, nevertheless, observe that I have alwa^^s met 

 with A. Mantellii in the lower beds of this group, whilst 

 A. Rhotomagensis appears to occupy the middle beds ; and I 

 have remarked that the two species are rarely found together. 

 In those parts of France where the chloritic chalk is greatly 

 developed, in the south-west, for instance, the Ammonites 

 do not disappear with the last deposits of the lower portion 

 of this group, but in the upper portions of the central beds, 

 there are no longer any traces of Ammonites. Thus, no 

 species is found in the white chalk, at which period Ammo- 

 nites do not appear to have existed. At present, no species 

 of the chloritic chalk has been found in the gault; it is certain 

 that all the species which I have quoted in the third group 

 are characteristic of it, and may be used for the purpose of 

 distinguishing it, under whatever mineralogical characters it 

 may present itself. 



SUMMARY. 



After the total disappearance of the Ammonites of the Ju- 

 rassic formation, we find appearing on the surface of the 

 globe, during the first epoch of the l>i eocomien, Jifty-three 

 species entirely different from those buried in the preceding 



