442 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [JunC 7, 



Table (continued). 



Class of the Organic Remains. 



Number of species. 



London 

 Clay. 



Bracklesham 

 Sands. 



Common to 

 the two series. 



ECHINODERMATA 



Crinoidea 



Ophiuroidea 



Asteroidea 



Echinoidea 



ZOOPHYTA. 



Zoantharia 



Alcyonaria 



FORAMINIFERA. 



Stichostegia 



Helicostegia 



Enallostegia 



Agathistegia . . . 



PLANTiE. 



See pp. 413 & 454 



5 

 1 

 6 



17_ 



7 



3 



10 



13 



4 



4 



_2 



23 



106 





 

 

 J_ 

 1 



15 

 J_ 



16 





 6 

 

 3 



y 



3 



Admitting certain differences of condition, it is still evident that 

 there is a well-marked and maintained distinction between the organic 

 remains of the London Clay and of the Bracklesham Sands — a distinc- 

 tion which has become more apparent as the fossils have become 

 better known. This fact being established with regard to the more 

 important marine member of the London Tertiaries, we will now (in 

 order to include the whole series, and at the same time to enable us 

 to embrace a wider range of conditions than that afforded by the 

 London Clay only) take the entire group of the London Tertiaries, 

 which vdll give us the sestuarine, freshwater, and terrestrial, as well 

 as the marine conditions of that period, and briefly consider its rela- 

 tions, not only to the overlying Tertiary group, but generally also to 

 the underlying Cretaceous series. 



Taken in conjunction with the Basement bed of the London Clay, 

 the Woolwich and Reading series, and the Thanet Sands, the organic 

 remains (the plants excepted) of the London Tertiaries present the 

 following total number of species* : — 



* Among the species ranging upwards are several wlaich miss the Bracklesham 

 Sands, but reappear in the Barton Clays : thus in the Molluscs we have the Pleu- 

 rotoma colon, P. comma, Murex frondosus, Cancellaria Iceviuscula, Fusiis inter- 

 ruptus, Natica siyaretina, Cultellus affinis, and Scalaria undosa ; in the Annelids, 

 the Ditriipa incrassata and Serpula crassa ; whilst in the Echinodermata, the 

 Ophiura Wetherellii and Hemiaster Brandetnanus are both quoted by Prof. Forbes, 

 but with a doubt, from the neighbourhood of London and from Barton : in the 

 Zoophytes, the Graphularia Wetherellii is the only one mentioned by M. Milne- 

 Edwards as occurring at Highgate and Barton. 



