AMMOiSITES — ZOOLOGICAL, ETC. 



difference in the composition of the species. If some cor- 

 responding strata were wanting, we might imagine that por- 

 tions had disappeared in the Parisian basin, whilst on the 

 contrary, as I have proved by personal examination of the 

 localities, all the Provenpal strata are found there. The 

 lower strata of the inferior system of the Provence, corres- 

 ponds for instance, to the blue marls of the Department of 

 Haute Marne. The chloritic or compact limestones, con- 

 taining A. radiatus, correspond to the clay and limestone 

 with spatangus of the same place, whilst the black or white 

 limestones, which contain Nautilus requienianus, correspond 

 to the limestone ostreenne of Haute-Marne, and the clays of 

 Gargas (Vaucluse), and of Vergous ( Basses- Alpes), perfectly 

 represent the clay with Phcatules of Haute-Marne and Aube, 

 as these strata contain species identically the same, and bear 

 evidence to their perfect agreement. I think, then, that the 

 Proven yal basin, at the Neocomien period, was separated 

 from that of Paris, and that its fauna, as regards Ammonites, 

 has been much the most abundant. 



2nd. I find in the Paris basin, among the lower strata of 

 the Neocomien, five species, amongst which, as I have al- 

 ready stated, four are common to the Proven9al basin, and 

 three {A. Cryptoceras, Leopoldims Bxid radiatus), simultane- 

 ously exist in the Jura. There remains after these distinctions, 

 a single species {A. bidichotomus) peculiar to the Paris basin. 



Of the six species of the upper strata, one only, A. nisus, 

 is, at the same time found, in the Proven9al basin, and only 

 one other, A. Deshayesi, in the Jura. There are, then,/oMr 

 species peculiar to the Paris basin, of the Departments of 

 Aube and Haute-Marne. 



As in the Proven9al basin, we evidently see that, inde- 

 pendently of the species common to other basins, so there 

 are a sufficient number of distinct species in the Paris 



