196 DUBLIN NATTJBAL HT8T0ET SOCIETY. 



ants of the surrounding districts, who come to fish here on Sundays, and 

 regale themselves during their stay on periwinkles procured at the neigh- 

 bouring town. The bed of the lake is a muddy diluvium, full of all the 

 above-named species, the periwinkle excepted. The commonest are — 

 Z. pereger, abundant ; L. stagnalisy abundant ; Planorhis marginatus, 

 abundant ; Valvata piscinalis, local ; Bithynia tentaculata, abundant ; 

 Cyclas cornea f abundant ; Anodonta cygnea, scarce, apparently wanting 

 in base of bed. The others enumerated before seem scarce. This dilu- 

 vium is partly made up of stones and fragments of woody plants and 

 grasses, so much so as in places to give it a peaty appearance ; bones of 

 quadrupeds and birds also occur in this. 



Beneath this deposit (the maximum thickness of which may be about 

 four feet) is a bed of marl, composed of shells identically the same as 

 those imbedded in the surface-soil, and yet living in the lake. The 

 species are not nearly so numerous. The following are the only ones I 

 could discover in the marl : — Z. pereger, which may be called the basis 

 of the marl, as not a cubic inch can be examined without finding this 

 shell, either whole or in fragments. Z. stagnalis and Bithynia tentaculata 

 range next in abundance ; then Valvata piscinalis, Planorhis marginatus, 

 and Cyclas cornea, both of which are locally abundant. There does not 

 appear to be a trace of any of the other above-mentioned species. The 

 marl is also full of vegetable remains, such as twigs and leaves of trees 

 and grasses. It is of a buff colour, and is highly calcareous, effervescing 

 freely with acids. 



At Licknaun Lough the marl lies in denuded basins or troughs of 

 the limestone drift (sometimes resting immediately on the adjacent rock), 

 and a large boulder frequently interferes with the continuity of the de- 

 posit. The pockets in which the marl occurs are local. The accompa- 

 nying rough sections, which are only an approximation, not being drawn 

 to scale, will give an idea of how the marl lies, and of the present ap- 

 pearance of the lake. The greatest visible thickness of this bed is about 

 three feet, but it probably attains to much more than this. If the margin 

 of the lake should ever become submerged and converted into a geologic 

 strata, the marine species occurring there might lead to much confusion, 

 and the history of the cause of their occuiTcnce shows the danger of 

 theorizing on the mere presence of marine species inland without careful 

 inquiries as to the cause of their occurrence. To the east of Ennis, near 

 the town, the marl is covered by from four to six feet of bog, and further 

 east, in the neighbourhood of Quin, and south thereof, it occurs in several 

 places beneath either bog or alluvium. The shells found here are the same 

 as those in the marl at Licknaun Lough. 



The ballot having been opened, the following gentlemen were de- 

 clared duly elected : — 



Ordinary Member: — Henry Thomas Vickers, Esq., 81, Lower Leeson- 

 street. 



Corresponding Member : — Robert Warren, Esq., BaUina. 



The Meeting then adjourned to the 3rd of June. 



