xvin. SHELLS IN THE GRAVEL. 467 



from loamy bands which divide the gravel at Summertown, north 

 of Oxford, not far from Port-Meadow, and 20 feet above the 

 present floods. These shells are in the Oxford Museum, and 

 appear to be of the following species : 



Pisidiupi amnicum. 

 Limn sea peregra. 

 Pupa muscorum. 

 Valvata cristata. 

 Bithynia ventricosa. 



Lately, on renewing a search in the pit at Kidlington, I regretted 

 to find that the low cliffs of gravel were mostly destroyed. In 

 a band of loamy consistence, two feet deep, under gravel, were 

 found the following shells : 



Planorbis marginatus. 



Achatina acicula; some specimens clear and pellucid (recent), others white and 



chalky. 

 Helix rufescens. 



In the sandy drifts mixed with this gravel at Yarnton, to the 

 depth of 10 feet, we find land shells; viz. Pupa muscorum, in 

 plenty ; Helix hispida, a few ; and one fresh-water shell, viz. 

 Limnaea peregra, a few small specimens. 



The clay-pits at Summertown, excavated through gravel some 

 twenty feet above the floods, have yielded at a depth of ten 

 feet 



Ancylus lacustris. 

 Limnaea peregra. 

 Helix radiata. 

 Valvata piscinalis. 



The gravel deposits near Wittenham have fortunately been 

 watched with interest by a good observer, the Rev. J. C. Clutterbuck, 

 M.A., Vicar of the parish. In this gravel deposit, containing oolitic 

 fragments, chalk flints, and red quartzite, are some bands of finer 

 matter, a kind of sandy loam mixed with small vegetable fragments 

 a laminated, somewhat peaty deposit from stagnating water. In 

 a thin deposit of this kind, at a depth of five feet under gravel, 

 were found the following shells : 



Bithynia tentaculata, in plenty. 

 Pupa muscorum, in plenty. 

 Helix rufescens. 

 Valvata cristata (?). 

 Pisidiuoi amnicum. 

 H h 1 



