8o The Irish Naturalist, [March, 



I think that this may help to explain one way in which a 

 large number of species of land shells might get mixed with 

 marine species during the formation of a raised beach, such as 

 that at Portrush, described so many 3'ears ago by general 

 Portlock, and whose present condition Mr. S. A. Stewart 

 notes in Irish Naturalist, 1897, page 287 ; while the small 

 modern shell-pockets in our sand-hills ma}^ help to show how 

 much older and larger land-shell deposits, such as the sub- 

 fossil deposit at Dog's Bay, were formed, or a somewhat similar 

 one found by Canon Norman on the beach at Madeira, and 

 described in a paper he read before the Newcastle-on-Tyne 

 Nat. Hist. Society, Nov., 1897. 



This Dog's Bay deposit is closely connected with the '* black 

 band" or old sward discovered there by Mr. R. D. Darbishire 

 in 1865, and described by him in the Jourjial of Conchologyy 

 1885. After the Field Club Union Conference in Galway, 

 1895, a contingent who visited Dog's Bay daily for several 

 days found that the *' black band " was gone, but we dis- 

 covered still remaining some local patches of a thicker 

 deposit, much lighter in colour, formed by myriads of similar 

 shells in a matrix of foraminiferous sand, finely comminuted 

 shells and a little earth}^ matter.^ (Some of us again visited 

 the place in April, 1896, and found the little sections being 

 rapidly destroyed by the wind, aided by cows rubbing against 

 and tramping over them). We agreed with Mr. Darbishire 

 that the conditions of life on and near the little peninsula must 

 have been very different at one time to what it is at present — 

 now, the bare sandy neck between Gorteen Bay and Dog's 

 Bay is utterly devoid of shell life and the wind-swept areas 

 adjoining hardly less so ; while the deposit consists of masses 

 of shells, many of which will only live where there is plenty 

 of moisture and vegetation, as on the slopes of Whitepark. 

 These shells may have collected from similar slopes and 

 marshy ground then near at hand ; the "black band" seems 

 to indicate the latter, and covered by the light foraminiferous 

 material— still present in very large quantities — in the way in 

 which we saw it travelling far above high water mark under 

 the influence of a westerly wind, might very quickly in a 

 warm and moist climate like that of the West coast form such 

 a deposit. Two of my companions, Messrs. Collier and 



1 See Mr. Stauden's article, Irish Naturalist, 1895, page 269, 



