NOTES ON THE DISTRIBUTION OF LAND AND 
FRESH WATER MOLLUSCA IN HOLDERNESS. 
Bet: Peron, B-Sc.5.A. 
(Read September 12, 1900.) 
I.—LAND SHELLS. 
HE land shells of Holderness do not furnish a very 
T extensive list, as there are neither chalk hills nor large 
woods. Few species have appeared on the new lands 
near the Humber, and there aquatic mollusca are also scarce, 
all the water being brackish. On the older lands woodland 
species are occasionally found in small numbers, and the 
explanation of their appearance in isolated plantations affords 
interesting problems in shell distribution. 
In the low cliff on the Humber side, at the eastern end of 
Paull Battery, a small section has recently been made, from 
which gravel was obtained for building the searchlight station. 
Here the subterranean Achatina acicula was very abundant 
(1893)—the only Holderness record. All the specimens were 
dead, and were found at a depth of two to three feet. The 
hill is separated from Boreas Hill and Rose Hill by low 
ground which must formerly have been salt marsh. I failed 
to discover it either at Boreas Hill or Rose Hill, or at Kelsey 
Hill. It is usually found at the roots of trees, and is probably 
a relic of the time when this hill extended further south, and 
was as well wooded as Boreas Hill is now. 
A mile further to the east, opposite Paull Holme, the river 
bank turns in abruptly, leaving outside, for no apparent 
reason, a grassy area which is covered only at the highest 
spring tides. Pupa marginata occurs under pieces of chalk on 
a small ridge which runs across this area parallel to the main 
bank. I once found a field vole’s nest, lined with daisies, 
under the same stones, which seems to indicate that it is not 
often flooded. The Pufa cannot have travelled from the 
mainland, for they would have to cross a salt ditch, filled 
at high water; and, a better reason, there are no others in 
South Holderness, except at Spurn. They may have been 
brought with the chalk used for making the bank, though 
they would hardly be found on fresh chalk; and, in that case, 
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