PRESTWICH BRITISH AND FOREIGN TERTIARIES. 217 



organic remains agree with species found in the sands of Bracheux 

 and Rheims, and afterwards consider the relation they bear to those 

 of the "Lignites" of the Soissonnais. 



The number of described species in the immediate district of 

 Woolwich* is forty-two, of which the following nineteen are found 

 also in the above-named sands in France. 



Area depressa, Sow. (A. striatularis, Teredina personata, Desk, 



Mell. ?) Buccinum fissuratum, Desk. ? 



Cardium Plumsteadiense, Sow. Calyptraea trochiformis, Lam. 



Corbula Regulbieusis, var. /3, Mor.f Cerithium variabile, Desk. 



Cyrena cuneiformis, Fer. Fusus latus, Sow. {F. deceptus, Desh. ?) 



intermedia, Mell. planicostatus, Mell. ? 



Nucula fragilis, Desh. Melania inquinata, Def. 



Ostrea Bellovacina, Desh. Melanopsis buccinoides, Desh. 



tenera, Sow. ( 0. angusta, Desh. ?) Neritiua pisiformis, Fer. ? 



Pectunculus terebratularis, Lam. vicina, Mell. ? 



Of the other twenty-three species, fourteen are new ; and, as there 

 are still many undetermined species from the Bracheux and Rheims 

 sands, it remains to be seen how many of these new forms may be 

 identified upon a more thorough examination. Deducting these 

 fourteen species, there is a remainder of nine, eight of which, although 

 not occurring in the marine beds of Bracheux, exist nevertheless in 

 those fluviatile and freshwater beds (lignite series of the Soissonnais) 

 which I believe to be subordinate to these sands. 



Viewing, therefore, the Woolwich and Reading fauna as a whole, 

 and striking out the newly described species and the more freshwater 

 forms which belong to the subordinate lignites, we have twenty-nine 

 estuarine and marine species. Out of this number twenty-two are 

 found in the sands of Bracheux and Rheims, — evidence which, allow- 

 ing for variations produced by geographical distribution, I take as 

 strongly conclusive of the correlation of these two groups in the 

 Paris and London tertiary districts. 



§ 5. Middle beds of the Woolwich and Reading Series, — the 

 Fluviatile Clays and Lignites ; " Lignites du Soissonnais." 



Extending over a very small portion of the area of the Woolwich 

 and Reading series, but more largely developed in France, are certain 

 well-marked beds of clay with occasional lignites, characterized by a 

 well-known freshwater and fluviatile fauna. These beds have been 

 generally considered by continental geologists as distinct from the 

 lower marine sands of Bracheux and Rheims ; but if I am right in 

 correlating these sands with the lower part of the Woolwich and 

 Reading series, then, as we have in this country throughout the 



* Those with " C " attached in my former paper. As that list can be readily 

 referred to, I do not give it again here. See Quart. Journ. Geol. Soc. vol. x. 

 p. 117 ; see also further on, p. 219. 



t This species is, I believe, identical with the Bracheux Corbula, described as 

 C. longirostris, Desh., — a name at present restricted to the Fontainebleau species, 

 from which the one from Bracheux is now known to differ. There is an unde- 

 scribed Dentalium in the two deposits which also seems identical. 



