342 



THE GEOLOGIST. 



other basins than during the Neocomien period ; that some 

 dislocations of the strata allowed a greater number of species 

 to pass from one sea to the other^ they, nevertheless, retain- 

 ing still some peculiar species. 



2nd. The Parisian basin furnishes me, in the lower beds, 

 with twelve species ; five are common to the Jura, five to 

 the Ardennes and two to Provence ; there are, notwithstand- 

 ing, five species peculiar to it, all found at Wissant : A. au- 

 ritus, Fittoni, lautus, splendens and tuberculatus. In the 

 upper beds I am acquainted with thirteen species, eight of 

 which are likewise found in the Proven 9al basin, ten in the 

 Jura, and seven in the Ardennes and Meuse. There re- 

 mains but one species peculiar to the Parisian basin A, Cle- 

 mentinus. Dissimilarities disappear by comparison ; we can 

 only say that at the periods of the lov/er beds of the Gault, 

 the Parisian and English basin had two deposits in the 

 north, those of Wissant and Folkstone, containing species 

 totally different from those found in the other basins at the 

 same period. 



3rd. The Jura, perte du Rhone, and Savoy, afford at pre- 

 sent, five species in the lower beds, four of which are found 

 in the Parisian basin and four in the Ardennes ; leaving but 

 one species pecuhar to them. In the upper beds I remark 

 that, out of fifteen species, eight are common to the Pro- 

 venyal basin, eleven to the Parisian basin, and six to the 

 Ardennes ; leaving but three peculiar species, A. Brottianus 

 and Itierianm from the perte du Rhone, and A. Hugardianus 

 from the perte du Rhone and Savoy. We see that the 

 greatest analogy exists between the Parisian basin, the Jura 

 and Savoy. 



4th. The Gault of Ardennes and the Meuse has furnished 

 at present, thirteen species from the lower beds, two of 

 which are common to Provence, five to the Parisian basin, 

 and four to the Jura ; after which, there remain seven spe- 



