91 



LAND AND FRESH-WATER MOLLUSCA OF 

 UPPER AIREDALE, YORKSHIRE. 



H. T. SOPPITT AND J. W. CARTER, 



Ex-Presidents of the Bradford Naturalists' Society. 



Some years ago the Bradford Naturalists' Society mapped out a 

 portion of the North-West Riding of Yorkshire for the purpose of 

 investigating its fauna and flora. The district thus mapped out 

 includes (i) the Yorkshire portion of the Lune drainage; (2) the 

 Ribble drainage, Yorkshire portion ; (3) the drainage of the 

 Wharfe from its source to its junction with the Washburn below 

 Otley; and (4) the drainage of the Aire from its source to the 

 boundary of Leeds Borough. During the last few years the Aire- 

 dale portion of the district has been most assiduously worked for 

 mollusca, as the following list shows, and it would be interesting 

 for comparison if conchologists investigating the more eastern 

 portion of the valley would publish the results of their work in the 

 pages of The Naturalist. 



The river Aire has its source at Malham Tarn, a large sheet of 

 water covering 153 acres, which is fed by a number of small streams 

 having their origin on Fountains Fell and Hard Flask. The whole 

 of the district down towards Skipton is of a Limestone character — 

 Mountain Limestone and Yoredale; beyond, to the limit of our 

 district it is chiefly Millstone Grit. 



Owing to the comparative absence of stagnant ponds, dykes, etc., 

 several common species, which might be expected to occur, are 

 apparently absent, e.g., Physa fontinalis, Valvata cristata., etc. ; and 

 to the land species Aane litieata and Achatina acicula may possibly 

 yet be added. The list is mainly the combined work of the following 

 members of the Bradford Naturalists' Society — Messrs. J. Beanland, 

 J. A. Hargreaves, M.C.S., F. Rhodes, M.C.S., W. West,' F.L.S., and 

 the writers; when otherwise the recorders' names are given. To Mr. 

 Hargreaves we are specially indebted for valuable assistance rendered 

 in the compilation of the list, and to Mr. James Ellison of Steeton 

 for information concerning that portion of the district. 



For the examination of critical forms our thanks are due to 

 Messrs. John AV. Taylor, Ex-President of the Concliological Society, 

 W. Denison Roebuck, F.L.S., and George Roberts, M.C.S., of 

 Lofthouse. Every species and variety mentioned in the list, without 

 recorder's name being attached, has been verified by one of the three 

 last-named gentlemen, or by ourselves. The arrangement followed 

 is that of the Conchological Society's List of British Land and Fresh- 

 water Mollusca, 1883. 



March 1888. 



