136 
A letter was afterwards read, addressed to the Rev. Dr. Buck- 
land, President of the Society, by R. Griffith, Esq., P.G.S. of 
Dublin, respecting the geological relations of the several rocks of 
the South of Ireland. 
This communication was accompanied by a copy of Mr. Griffith’s 
Geological Map of Ireland ; and its principal object is to explain why 
he has coloured, as old red sandstone and carboniferous limestone, 
extensive districts of the counties of Kerry, Cork, and Waterford, 
which had been previously considered to be transition. 
The geological base of these counties is clay slate passing into 
quartzose slate, quartz rock, and occasionally conglomerates. ‘This 
is particularly the case in the peninsula of Corkaguinny or Dingle 
in the county of Kerry; and as the succession of rocks forming the 
south of Ireland is well exposed in that district within a short dis- 
tance, Mr. Griffith selected it for the purpose of explaining his views. 
The lowest formation on the sea-shore at Brandon Bay consists of 
black and red clay slate, and gray quartz rock. The beds are nearly 
vertical, but occasionally dip 70° or 80° to the south. In some lo- 
calities near the Bay, the slates alternate with red and gray quartzose 
conglomerates ; and on the western coast of the peninsula, at Doon- 
guin, Ferriter’s Cove, and Filaturrio, S.E. of Dingle, the slate con- 
tains Orthis, Terebratule, corals, &c. This series is succeeded, un- 
conformably, by beds composed of rolled masses of quartz and mica 
slate, in an arenaceous base, and it is assigned by Mr. Griffith to the 
old red sandstone. On the summit of Cahirconree mountains, this 
conglomerate, associated with beds of fine-grained red sandstone, dips 
to the east at an angle of 10°. Proceeding eastward, in ascending 
order, the conglomerate disappears, and the formation consists of red 
and reddish-brown quartzose sandstone, alternating with coarse-red 
slate, flagstone, and occasionally green slates. These strata are 
succeeded, conformably, by a fine, yellowish-gray sandstone, forming 
the commencement of the carboniferous series. The sandstone con- 
tains Calamites, and at Gortaclay, 2 miles west of Curreen’s Bridge, 
indistinct bivalves. Its upper beds alternate with coarse and fine 
dark-gray clay slate, abounding with Product, Spirifere, Tere- 
bratulz, Encrinites, corals, and other fossils. Continuing to ascend 
in the series, beds of carboniferous limestone, containing the same 
organic remains, alternate with the fossilliferous slate; then appear 
strata of gray, fine-grained, indurated sandstone, alternating in the 
upper part with slate; next, a series of strata of limestone and greenish- 
clay slate, containing the same fossils; beyond which the slate gra- 
dually disappears, and the whole mass is composed of limestone. In 
the flat central space between Curreen’s Bridge and Castle Island, are 
probably shale and limestone. Near Castle Island occurs the upper 
limestone, abounding in nearly every known fossil of the carboni- 
ferous limestone of Ireland; and eastward of Castle Island is dis- 
played, in conformable position, the millstone grit, the lower shales 
of which contain, in considerable quantity, Encrinites, Posidonie, 
Spiriferee, Product, Ammonites, Orthocera, &c. 
