AMMONITES. — ZOOLOGICAL, ETC, 



which would lead one to imagine that it still possessed at 

 this period a peculiar fauna, pointing out its separation from 

 the other basins, and that it was still influenced by the same 

 conditions as at the period of the Gault. 



2nd. The Parisian basin furnishes eight species, five of 

 which are found in Provence, six in the Gulf of the Loire, 

 and four in the basin of the Pyrenees. Thus leaving, at pre- 

 sent, only A, rusticus peculiar to this basin. 



3rd. The Gulf of the Loire, out of thirteen species, fur- 

 nishes seven common to the Provenjal basin, five to the 

 Parisian, and six to that of the Pyrenees. There is, then, 

 but one species, A. Vibrayeanus, peculiar to the Gulf of the 

 Loire, which, though differing from the Parisian basin, has 

 probably been connected with it. 



4th. The basin of the Pyrenees, from Charente-Inferieure 

 to Perpignan, have furnished to the present period, eight 

 species, three of which are found in the Proven9al basin, 

 four in the Parisian, and six in the Gulf of the Loire. There 

 remain two peculiar to it. A, Pailleteanus and tricarinatus. 

 From the comparisons which I have made, it appears that 

 the basin of the Pyrenees, though seeming to have peculiar 

 species, approaches nearer to the Gulf of the Loire than to 

 any other portions of the seas of the period of the chloritic 

 chalk. 



5th. The species of the Jura are those which we find indis- 

 criminately throughout all the other basins, and particularly 

 in the Parisian basin. 



6th. The species of the Ardennes are nearer allied to those 

 of the Loire than to any of the other basins. 



7th. Lastly, the Ammonites of Cotentin, though furnish- 

 ing two types distinct from those of the other basins, indi- 

 cates by A, Lewesiensis, their identity as regards time, with 

 the third group of the cretaceous formation. 



In conclusion, at the first epoch of the chloritic chalk, with 



