FITTON S SECTION AT ATHERFIELD. 



327 



he states he has not discovered the slightest trace in his Terrain 

 cretace inferieure : with this are found Mytilus, Melania, an Avicula, 

 and a small species of Pholadomya ; Cyrena fossulata, Avicula 

 7'homboidalis, and Pholadomya parva, appearing in myriads in the 

 doubtful tract near Vassy. Now it deserves remark that all these 

 genera exist in the Purbeck of England, and that M. Dunker, in his 

 recent important work, has figured more than thirty species of 

 Cyrena from the Wealden of Northern Germany*. 



I have not, in person, examined any part of M. Leymerie's district 

 on the AuBE ; but specimens of the Gault fossils from the vicinity of 

 Troyes, given to me by M. Clement Mullet, identify that deposit 

 with ours ; while the number of species in the Terrain Neocomien of 

 M. Leymerie, to be found in the Table annexed to this paper, can 

 leave no doubt that the strata which contain them are the same ; a 

 resemblance supported by the continuity of this tract with that of 

 Vassy. Nor should I despair of finding even traces of the Wealden 

 also in the department of the Aube. 



A valuable collection of specimens from the vicinity of Atjxerre, 

 which was placed at my disposal by my friend M. Constant Prevost, 

 has enabled me to compare some of the fossils of that country with 

 the subject of the present paper. The collection was made, evidently 

 with great care, by M. Delajoye himself, the author of some excel- 

 lent observations on that region, which appear in the French Bulletin 

 for ISSSf. The specimens consist chiefly of a calcareous stone of 

 a buff colour, apparently tinged by iron (no doubt a portion of the 

 Calcaire a Spatangus), and many of them contain particles of oolitic 

 iron ore. The following list will show the affinity of the deposit 

 from whence they come with our lower greensand : — 



List of specimens from Auxerre. 



Area Gabrielis. 



Artemis Vectensis, Forbes. 



Astarte gigantea ? 



obovata {A. Beaumontii, Leym.). 



near to laticostata. 



Cardium imbricatorium. 



Voltzii. 



peregrinosura. 



Cerithium terebro'ide. 



Crassatella Robinaldina. 



Cyprina rostrata. 



Exogyra harpa. 



Couloni {l/Bvigata, Sow.). 



Gervillia aviculoides. 



anceps ? 



Isocardia Neoconiiensis. 

 Natica bulimoides. 



Cornueliana, cV Orb. 



Panopaea Neocomiensis. 



plicata. 



Pecten quinquecostatus ? 



• orbicularis ? 



Pholadomya elongata, d' Orb. (P. gi- 



gantea of Sowerby : Geol. Trans. 2ud 



ser. iv. plate 14, fig. 1.) 

 Pteroceras. 



which the oolitic particles have left only vacant cavities (which no doubt M. Cor- 

 nuel would regard as " vacuolaire"), is frequent in the thin beds of the Purbeck 

 limestone, immediately above the Portland, in the Vale of Wardour. The whole 

 of these peculiar beds in Dorsetshire, Oxfordshire, and Bucks, well deserves a 

 careful examination. The researches of the Rev. Mr. Brodie show how much 

 can be done by such an inquiry. 



* ' Monographie der Nord Deutschen Wealdenbildung.' Brunswick, 1846. 



t Tome X. p. 21, &c. 



