412 JOURNAL OF CONCHOLOGY. 



CONTRIBUTIONS TOWARDS A LIST OF 

 IRISH MOLLUSCA. 



By T. G. MIIvNE. 



//. 



Notes on the Land and Freshwater Molluscs 



OF AcHiLL Island. 



(Read before the Conchological Society). 



The land and freshwater molluscs of Achill Island — especially 

 the former — present several points of interest; not only as 

 inhabiting almost the most westerly part of the British Isles, 

 but, because, as I hope to show, the fauna has been materially 

 altered in, geologically speaking, recent times. These Notes 

 embody the results of two visits — in August, t886 and Sep- 

 tember, 1888 — when, from the Slievemore Hotel, at Dugort, 

 as head-quarters, I worked the northern half of the island, and 

 the neighbouring islet of Innishbiggle, supplemented with pass- 

 ing remarks on a few gatherings from the shores of Clew Bay. 



The geological formation at Achill shows rocks of the 

 metamorphosed lower silurian, which give place at Achill 

 Sound to the old red sandstone. This forms the north shore 

 of Clew Bay, while the east end, from Newport to Westport, is 

 limestone. In Achill, however, the collecting grounds of the 

 conchologist are limited by the peat which covers the greater 

 part of the island. The north coast is a series of cliffs and 

 precipices, from five hundred to two thousand feet in height, 

 backed by a ridge which runs for about five miles from Achill 

 Head to Slievemore, where it reaches its highest point, 2,204 

 feet. On the south this slopes down more gently, and by the 

 villages of Keem, Dooagh, Keel, Slievemore, and Dugort are 

 small patches of cultivated land. East of Keel there is a small 

 extent of level sandy ground, and a similar sandy warren forms 



J.C, vi., Oct., iSgt 



