GEOLOGICAL SOCIETY OF DUBLIN. 
5 
confounded with these rocks. With what series these brownish-red grits 
should he classed, is a question that I trust the present discussion may 
determine. But in the remarks that I shall have to make on the south 
of Ireland, I hope I shall be able to show a series of analogous litho¬ 
logical equivalents, which may contribute to a satisfactory settlement in 
regard to the system with which they ought to be classed. I shall not 
enter more at length, at present, into the question relative to the nor¬ 
thern rocks, further than to remark that there exists sufficient simila¬ 
rity between the three districts I have mentioned, to justify a comparison. 
But I shall now proceed to advert to the rocks, of which the south of 
Ireland is composed. 
It will be seen by reference to my Geological Map, that the Old Bed 
Sandstone strata, as distinguished in that Map both by colour and 
the letter F, consisting of alternating beds of red and green shales, 
red sandstones and conglomerates, have an extensive range in the 
southern counties, pervading portions of Kilkenny, Waterford, Lime¬ 
rick, Cork, and Kerry, as well as Clare and Tipperary. Commencing in 
the counties of Kilkenny and Waterford, and extending mere or less 
continuously in an east and west direction through the counties of Tip¬ 
perary, Limerick, and Cork,—we find the Old Bed Sandstone strata 
lying conformably beneath the Lower Limestone, and Yellow Sandstone 
of the Carboniferous system, and resting upon the upturned edges of the 
Silurian rocks in an unconformable position, till, reaching the Old Bed 
strata in the county of Kerry, they are found preserving the same re¬ 
lative positions, passing through Slievemish and Caherconree, to the 
brownish-red, and greenish-gray grits, and the red, green, and purple 
clay slates of the Dingle district, which conform to and overlie the fos- 
siliferous Silurian rocks of Ferriter’s Cove, these being again overlaid 
unconformably on the western shore at Sybil Head by the beds of the 
Old Bed series. 
Ho difficulty hence arises in regard to the position of the Old Bed 
series in the south of Ireland, it having been clearly ascertained to 
conform to the Carboniferous strata above, while resting unconformably 
upon the Silurian series beneath. The only question that will arise 
regarding it is, as to what system it will of right belong. And here I 
must enter upon an explanation of the principle of subdivision by which 
I have been hitherto influenced. Finding, in the course of my geolo¬ 
gical researches, that certain rocks below the lowest beds of the lower 
Carboniferous Limestone conformed to them, and contained the same 
fossils, I was led to add them to the Carboniferous system, the boundary 
at the base of the Mountain Limestone, as it had until then been termed, 
being found to be far too limited. These lower rocks I was ultimately 
led to consider as divisible into two groups, the upper of which I 
proposed to call Carboniferous Slate, and the lower, Yellow Sandstone. 
In respect to this latter and lower of the two series, it became a 
question as to where the line of division between them and the red beds 
lying conformably beneath should be drawn; and the discovery of cer¬ 
tain plants, apparently of a Carboniferous type, and at present known as 
