LIST OF PETERBOROUGH MOLLUSCA. 



Zonites nitidus 



Thorpe 

 Thorpe Cornbrash 



AUTHENTICATED MATERIALS FOR A LIST 



OF THE LAND AND FRESH-WATER MOLLUSCA 



OF MID-WEST YORKSHIRE. 



[Extracted from the Record-Books of the Conchological Society]. 

 PART L 



Fresh-water Shells. 



Yorkshire is divided — for the purpose of recording the 

 localities of moUusca — into five vice-counties, the same as are 

 used by botanical topographers. Three of these are on the 

 western side of the central dividing line of the county (the 

 rivers Wiske, Swale, and Ouse), and the one now dealt with is, 

 as its name implies, the middle of the three. Its northern 

 boundary is formed by the familiar line of demarcation between 

 the North and West Ridings, which is however continued west- 

 ward in such a manner as to throw the Dent and Sedbergh 

 district into North-West Yorkshire. The line which separates 

 our present district from South-\^'est Yorkshire is purely arbitrary, 



J.C, iv., April, 1884. 



