51 



NOTES ON THE LAND AND FRESH-WATER SHELLS 



OF CUMBERLAND/^ \^fz^X^^^^^^en^e^,x,.U^ 



By Miss DONALD, of Stanwix. 



(Read at the Carlisle Annual Meeting.) 



I HAVE collected most of the shells recorded in the subjoined list 

 myself in the immediate neighbourhood of Carlisle ; but a few 

 have been obtained from greater distances, where I have had 

 opportunity to search for them. I have inserted in the list the 

 names of the mollusca mentioned by Dr. Gwyn Jeflfreys in his 

 British Conchology, and by Capt. Brown in his Land and Fresh- 

 water Conchology, as being found in localities in Cumberland and 

 Westmorland which I have been unable to visit myself. 



The abundance of land-shells depends greatly upon the nature 

 of the soil ; they are most plentiful on calcareous rocks. Slates, 

 grits, and igneous rocks form the higher hills of the Lake District 

 in the south of the county ; north of this a lower range of hills is 

 composed of alternate beds of limestone, sandstone, and shale; 

 then comes a narrow strip consisting chiefly of sandstones. The 

 rocks of the remainder of the county may in a general way, be said 



to consist of the sandstones and marls of the New Red Series 



limestone only occurring again in the north-east The surface of 

 the county is thickly covered with glacial drift over a wide area in 

 the north-west, where but little rock crops out. One could hardly, 

 therefore, expect to find a great number of species in Cumberland, 

 as but a small portion of its area is occupied by the outcrop of 

 limestone. 



