July, 1916. The Irisli Xatiiralisl. 10 1 
ON TWO SPECIES OF PISIDIUM (FOSSIL) NEW TO 
IRELAND. 
BY R. A. PHILLIPS, M.R.I. A. 
(plate II.). 
Along the courses of the greater rivers of the south of 
Ireland there occur large deposits of sand and clay, forming 
islands in mid-stream and banks by the river sides. The\^ 
consist of material swept, through many ages, from the 
lands through which these rivers and their tributaries flow, 
with here and there a mixture of shells and other river 
rejectamenta. These accumulations are at intervals eaten 
into by heavy floods and swept further down towards the 
estuaries, mingling on their way with the more recent 
debris of the river, the heavier materials, such as sand and 
shells, being left in places where the currents from various 
causes are weak, often fiUing up holes and depressions in 
the river-bed, while the lighter clay and vegetable matter 
drift off still further towards the sea. Thus new deposits 
containing a mixture of recent and fossil shells and sand 
are formed. 
Along the rivers Shannon, Suir, Barrow and Nore where 
some of these deposits occur near large towns and industrial 
centres the}^ become valuable and numbers of men get 
constant employment dredging or shovelling the material 
which the}^ bring in boatloads to the quays where it is 
sold for building and other purposes. 
With the object of examining their shell contents I have 
at various times during the past few years taken samples 
of these sands at Limerick, Waterford and New Ross, and 
have obtained from them interesting collections of land and 
freshwater shells which illustrate the past and present 
faunas of the rivers and their banks. 
Among these shells were found two species of Pisidium^ 
one, P. supinum, being new to Ireland and the other, 
P. parvulum, a species not previously noticed in the British 
Islands. Both species were identified by Mr. A. W. Stelfox, 
M.R.I. A., who detected them in gatherings, Vv^hich I sent 
him last January, of Pisidia taken in May, 19 13, from a 
deposit in the Suir near Fiddown, about fifteen miles above 
Waterford where that river separates the counties Waterford 
and Kilkenny. 
