230 



MR. A. S. KEXXARD & ME. B. B. WOODWARD OX [vol. lxxv, 



Ptvpilla muscorum (Linne). Abun- 

 dant. 



Vertigo antivertigo (Draparnaud). 

 Abundant. 



V.pygmsea (Draparnaud). Abundant. 



V. a ngnstior Jeffreys. Five examples. 



Truncatellina minutissima (Hart- 

 mann). Ten examples. 



Clausilia rvgosa Draparnaud. Two 

 apical fragments. 



C. pumila Pfeiffer. Four fragments. 



Succinea putris (Linne). Four ex- 

 amples. 



S. pfeifferi Eossmassler. Abundant. 



S. pfeifferi, var. schumacheri Andreae. 

 Abundant. 



S. oblonga Draparnaud. Abundant. 



Garychivm minim u m Midler. Three 

 examples. 



Limnsea pereger (Midler). Abundant. 



L.pahistris (Midler). Ten examples. 



L. truncatula (Midler). Abundant. 



L. stagndlis (Linne). Common (frag- 



* ments). 



Planorbis crista (Linne). One ex- 

 ample. 



P. vortex (Linne). Six examples. 



P. leucostoma Millet. Abundant. 



Bithynia tentecnlata (Linne). Two 

 examples (opercula common). 



Yalvata piscinalis (Midler). Common. 



V. cristata Midler. Two examples. 



V. macrostoma Stein. One example. 



Pomatias elegans (Midler). 



TJnio sp. Fragments. 



Corbicula fluminalis (Midler). Three 

 fragments. 



Sphserium corneum Linne. Three 

 valves. 



Pisidium amnicum (Midler). Abun- 

 dant. 



P. casertanum (Poli). Abundant. 



P. nitidum Jenyns. Abundant. 



P. milium Held. Two valves. 



P. pulchellum Jenyns. Three valves. 



P. subtruncatum Malm. Abundant. 



this 



No example of Pomatias elegans was found by us, 

 species is included on the authority of Mrs. Hughes. 



The problem of Barrington is a difficult one, and it nuw be 

 briefly stated as follows : — This deposit has always been considered 

 as of one age, and the mammalian remains which are obtained from 

 the lowest bed indicate a zone similar to that of Grays (Essex), and 

 certainty older than the Barn well- Abbey gravel. The mollusca, 

 however, do not support this view, for the} r would appear to 

 indicate a much later horizon. The probable explanation is that 

 two horizons are represented here. Corbicula fluminalis has only 

 been found in the lowest bed, with the mammalian remains. 

 Nearly all our material was obtained from above the lowest bed r 

 and Ave noticed that the freshwater shells were most abundant in 

 the upper part, nor was Yalvata piscinalis obtained from the 

 lower bed. This is a characteristic fossil which first makes its 

 appearance at Ilford and Barnwell Abbey. The general facies of 

 the mollusca indicates marsh conditions, certainty not lacustrine ; 

 while the freshwater species are identical with those from Chara- 

 marls. We think that the upper part of this deposit is much later 

 than that of Barnwell Abbey, and is probably a little older than 

 the deposit at Apcthorpe (Northamptonshire). 



Barnwell. 



The first list of mollusca from the important deposits at Barn- 

 well was published by the Rev. P. B. Brodie in 1844, twenty 

 species being recorded. 1 In 1S66 the Bev. E. S. Dewick increased 



1 Trans. Camb. Phil. Soc. vol. viii. pp. 138 39. 



