HOLOCENE MOLLUSCA FROM CLAPHAM 
YORKSHIRE. 
121 
J. WILFRID JACKSON, F.G.S., 
Manchester Museum. 
The shells referred to in this paper have all been collected 
from the talus masking a small cave or ‘ rock-shelter,’ known 
locally as Foxholes, on the left side of Clapdale, a little below 
the famous gorge of Trowgill. 
The cave is about 1,000 feet above sea-level, and is situated 
at the upper end of a small gorge cut back into the slope of 
the hillside through the undermining of the massive beds of 
Carboniferous Limestone. 
The shells occurred in a well-defined zone about 6 feet 
below the top of the talus at a point about 3§ feet outside the 
present line of cliff, and probably belong to a period when the 
cliff-face was relatively nearer to Clapdale than at the present 
time. 
They are evidently of some antiquity and the accumu- 
lation is obviously due to the washing down of dead shells 
from the higher slopes above the cave. Judging from their 
abundance and the restricted area of their distribution, a cliff 
must have persisted here for some considerable time ; then 
the ‘ overhang ’ gradually receded by the continued falling 
away of large and small fragments, until the face was cut back 
to its present position. 
The shells are all typically damp woodland species and 
characteristic of the Mountain Limestone, but their present-day 
representatives are almost all found at much lower altitudes 
in the district. 
If comparison be made with Mr. \Y. E. Collinge’s list of 
Clapham and District Mollusca, published in The Naturalist, 
for April, 1S90, (p. 109), it will be seen that all the species 
are living in the district at present, along with many others 
not yet found in the talus at Foxholes. Among the abundant 
living forms absent from the talus are : — Pyramidula rupestris, 
Vallonia costata, and Clausilia cravenensis (=var. dubia of 
Cl. rugosa of old lists). This absence may be accounted for 
by the fact that the above-mentioned forms are not essentially 
woodland species. 
The abundance and large size of some of the forms, in the 
talus, notably Hygromia rufescens and Yitrea cellaria, is a 
remarkable feature. Among the shells of the latter there is 
one example considerably larger than its fellows, measuring 
14.5 by 7 mill, and agreeing in this respect with the large Irish 
form described by Mr. A. S. Kennard as Vitrea hibernica. 
The average size of the remaining shells of V. cellaria is 12 by 
6.5 mill. 
1914 April 1. 
H 
