1850.] R. N. MANTELL ON THE OOLITE OF WILTS. 315 



few new species are named and described. The following abstract 



shows their distribution : — 



Kelloway Rock .... Radiaria, 3 genera. 



Conchifera, 16 genera, comprising 22 species. 



Mollusca, 5 genera. 



Oxford Clay Annelida, 1 genus. 



Conchifera, 5 genera. 



Mollusca, several genera. 



Cephalopoda, 6 genera. 



Pisces, 2 or 3 genera. 



Reptilia, 4 genera. 



Cornbrash Radiaria, 3 genera. 



Conchifera, 8 genera. 



Mollusca, 1 genus. 



Bradford Clay .... Radiaria, 3 genera. 



Conchifera,' 4 genera. 

 Thus it appears that from the small area of the bed of the Oolitic 

 ocean exposed by the railway excavations, there were obtained above 

 thirty genera of Conchifera, and seventeen of Mollusca, of which no 

 less than eighteen species belong to Cephalopoda. 



1 will only observe, that the spectacle daily presented to my view, 

 during the many months I was engaged on the construction of this 

 railway, strongly impressed on my mind the conviction that I was 

 exploring a mud-bank of an ancient ocean, to which terrestrial 

 plants and trees, and the shells of littoral and shallow water species 

 of mollusca, had been transported by currents, and promiscuously in- 

 termingled with the exuviae of the inhabitants of the profound depths 

 of the sea. 



The characters of a fluvio-marine formation given by M. Constant 

 Prevost seem particularly applicable to these deposits : — " Predomi- 

 nance des sediments alternativement argileux et arenaces regulierement 

 stratifies ; abondance de vegetaux terrestres et par suite d'amas et de 

 bancs de charbons ; presence d'animaux fluviatiles ou terrestres asso- 

 cies dans les memes conches a des animaux marins. On pent ajouter 

 que, dans les formations fluvio-marines pelagiennes, les argiles pre- 

 dominent sur les gres, que les fossiles sont bien conserves, qu'ils sont 

 isoles ou groupes avec ordre par families et par lits, que les fossiles 

 marins rappellent des animaux de haute mer ; enfin 1' absence presque 

 absolue des Polypiers pierreux*." 



List of Organic Remains obtained by Reginald N. Mantell, Esq. 

 from the Railway Cuttings above described. By John Morris, 

 F.G.S. 



Kelloway Rock. Conchifera. 



Pholadomya Murchisoni, Sow. 



Radiaria. acuticosta, Sow. 



Acrosalenia ? Panopaea (Pullastra peregrine, Phil. 



Cidaris ? sp.). 



Pentacrinus ? Modiola bipartita, Sow. 



* " De la Chronologie des Terrains et du Synchronisme des Formations," p. 5. 



