202 PROCEEDINGS COTTESWOLD CLUB 1903 
wished ; but with the Clifton Hampden deposit there is 
no such objection. 
Spherium rivicola is another interesting form. Though 
there is no reason to doubt that it is really a native, 
yet it is extremely scarce in deposits of either Pleisto-— 
cene or Holocene age. In the former beds it is known 
from Brentford and N.E. London; whilst in the latter 
it occurred at Westminster, Whitefriars, Faversham and 
East Farleigh, all which places are in the Thames drain- 
age area. At the present time it occurs as far north 
as Northumberland. 
Pisidium. Of the nine species which recent research 
has shewn to occur in the Holocene beds of England, no 
less than eight have been detected at Clifton Hampden, 
the missing form being P. pusz//um (Gmel.) Of these 
the most interesting is P. supinum, a species which, though 
abundant in the Thames Pleistocene beds, and not un- 
common in the Holocene beds of the same river, has not 
yet been detected living in these islands. But since this 
group is so often neglected on account of the supposed 
difficulties in identifying the species, there is still just a 
possibility that it may yet be found living in these islands. 
TABLE OF MOLLUSCA. 
SPECIES Bep A Bev B Bep C 
Agriolimax agrestis (Linn,) 
Vitrea nitida (Mill.) 
Arion ater (Linn.) ee 
Pyramidula rotundata (Mall, ase 
Punctum pygma@eum (Drap.) 
Vallonia pulchelia (Mill.) 
Hygromia hispida (Linn.) 
" granulata (Ald.) +3 
Helicigona arbustorum (Linn.) ... 
Helix nemoralis, Linn. 
un aspersa, Mill. 
Cochlicopa lubrica (Mill. 5 
Cecilioides acicula (Mill.) 
Pupa muscorum (Linn.) ... 
Succinea putris (Linn.) 
u elegans, Risso. 
Carychium minimum (Mill.) 
Ancylus fluviatilis (Mill.) 
Velletia lacustris (Linn.)... 
AM 
~A Me 
MM PM 
p we 
wn 
rm we 
MPP 
