part 3] 



MOLLVSCA FEOM THE CAMBRIDGE GRAVELS. 



233 



Planorbis Isevis Alder. Rare. 



P. crista (Linne). Rare. 



P. cari/natus (Miiller). Rare. 



P. umbilicatus (Miiller). Common. 



P. vortex (Linne). Rare. 



P. leucostoma Millet. Common. 



P. contortus (Linne). Rare. 



P. fontan us (Lightfoot). Rare. 



Segment ina nitida (Miiller). Rare. 



Physa fontinaUs (Linnc'). Rare. 



Aplexa hypnorwm (Linne). One ex- 

 ample. 



Belgrandia marginata (Midland). 

 Rare. 



Bithynia tentaculata (Linne). Abun- 

 dant. 



Va I va ta p isc i na I is (Miiller). Common. 



Vulvatu cristate Miiller. Rare. 



Vn in jiictorinii (Linne). Common. 



U. lit torn I is Lamarck. Common. 



Gorbicula flunmialis (Miiller). Com- 

 mon. 



Sphaerium corneum (Linne). Rare. 



Sph. mamanvm Kobelt. Common. 



Spli. locust re (Miiller). Rare. 



Pisidium amnicum (Miiller). Abun- 

 dant. 



P. casertanum (Poli). Common. 



P. nitidum Jenyns. Rare. 



P. pusilhnn Jenyns. Common. 



P. subtruncaturn Malm. Rare. 



P. henslotoanvm (Sheppard). Com- 

 mon. 



P. supinum A. Schmidt. Common. 



There is only one record which Ave consider it advisable to delete : 

 namely, Vertigo pus ilia. This was based on a single example said 

 to be in the Tomlin Collection, but we failed to find the specimen, 

 and Mr. Tomlin suggests that it was a large V. angustior. 



Mrs. Hughes has commented on the fact that various species were 

 sporadic in their occurrence, and this is borne out by an examination 

 of the Brady Collection. Unio littoralis and Ena montana were 

 both absent, while all the species of Limncea and Planorbis were 

 sparsely represented. Thus it would appear that the absence of 

 some names from the early lists may have arisen from the fact that 

 they did not occur in the exposures then open. 



The general facies of the mollusca indicates climatic conditions 

 similar to those of the present day, or possibly a little warmer. 



East Road , Barnwell. 



The late Prof. T. McKenny Hughes described a section behind 

 Rodney Brewery, East Road, Barnwell, 1 and a series of shells 

 obtained from the gravel is now kept in the Sedgwick Museum. 

 The species determined by Mr. Hugh Watson are : — 



Polita nit id nl a (Draparnand). 



Eulota fruticwm (Miiller). 



Helicella itala (Linne). 



Hygromia liberta (Westerlund). 



H. hispida (Linnc-). 



Vallonia sp. 



Arianta arbustorv/m (Linne). 



Helix nemoralis Linne. 



Ena montana (Draparnaud). 



This gravel is clearly of the 



Succinea putris (Linne). 

 Limtuea auriculario (Linne). 

 L. pereger (Miiller). 

 Planorbis sp. 



Bithynia tentaculata (Linne). 

 Valvata piscinaUs (Miiller). 

 Unio lift ara I i» Lamarck. 

 Corbicula flu miaul is (Miiller). 

 Pisidill/m amnicum (Miiller). 



same age as that at Barnwell 



Abbey. 



Milkman's-Lane Pit. 



In the British Museum ( Natural History) there is a small series 

 of mollusca (C. Birley Bequest), said to be from 'Milkman's-Lane 



1 ' Gravels of East Anglia ' Cambridge, 1916, p. 45. 



Q. J. G. S. No. 299. s 



