10 Proceedings. 
Helicodonta obvoluta) seems to have had a much more extensive 
range in Pleistocene time than it has today, being now a very 
local shell but fairly abundant in places where it occurs. 
Even in Cambridgeshire, at Harlton, the Rev. O. Fisher 
found a living specimen 33 years ago, and has found none since, 
though it is abundant in the fossil state, and not uncommon 
at Coe Fen, Cambridge. 
This snail is said to occur high up mountain-sides under 
sranite boulders, but it is certainly most abundant near water, 
where it can hide under willow-stems and near decaying wood. 
As, however, boggy places are common enough even on the 
summits of hills, and moreover elevations attract rain and mists, 
it may only be an apparent contradiction for this snail to 
choose seemingly the most arid and the most humid conditions, 
It seems to be extinct at the Horseshoe, and its occurrence 
at the depths mentioned, 24 to 32 feet, points to a time when 
the foot of Reigate Hill was probably boggy or marshy, a 
conclusion borne out by the immense number of Arion ater 
granules, and shells of Carychium minimum which occur at the 
lower part of the deposit and are only found where moisture 
is abundant. Favourable conditions for the existence of these 
molluscs may have been ended centuries or even thousands of 
years ago, either by natural causes or by Neolithic man, who 
was a tiller of the soil and whose tools are abundant enough on 
the top of Reigate Hill and the North Downs between Margery 
Grove and the Walton Road past the Yew wood, and on the 
Lower Greensand ridge. 
In Pomatias reflecus, Olivi, which occurs all through the 
Horseshoe deposit, we have our solitary British example of a 
genus which is well represented in the West Indies and on the 
Continent of Europe. It is a great pity that the ‘law of 
priority” has displaced the perfectly appropriate name Cyclo- 
stoma elegans, which was most distinctive, for Pomatias has a 
circular mouth, and its shape, sculpture, and colour are most 
elegant, whether it be of the pale buff, or brown, or grey-blue 
variety. 
But Pomatias is also distinctive, for it is one of our two 
