On the Old Red Sandstone of Ireland. 141 
Let it be clearly understood that in no place in the above 
discussed rocks of Cork, Dingle, Toormakeady, Louisburgh, 
Croaghmoyle, Curlew Mountains, or the Fintona district, have 
fossils been found to prove distinctly that they are of Silurian 
age. The only indirect evidence of that kind which can be pro- 
duced being the fossils in the Mweelrea beds, which may, per- 
haps, be on the same geological horizon as the unfossiliferous 
rocks of Toormakeady, Louisburgh, Croaghmoyle, the Curlew and 
the Fintona Mountains. While on the other hand it must be 
admitted that there are the already mentioned plants of Carboni- 
ferous type in the Dingle and Glengariff beds. Therefore it is no 
doubt possible, that if there really be such a distinct formation as 
the “ Old Red Sandstone” those rocks may belong thereto. It is 
evident, however, that they are all of similar age ;* and it is surely 
inconsistent that if the Dingle and Glengaritf beds with their Car- 
boniferous type plantsf are classed with the Silurians, the Curlew 
and Fintona rocks should be put in a separate formation and 
classed as “ Old Red Sandstone.” 
It would appear, then, that the lower and the upper parts of 
what has been spoken of as the “ Old Red Sandstone” do not 
belong to each other as parts of the same formation, but strati- 
graphically are to be classed, respectively, with the strata immedi- 
ately below and above them. 
(2.) We now come to the second division of our argument 
which is that the so-called “Old Red Sandstone” beds may be 
sometimes older than the Carboniferous Limestone and sometimes 
of the same age as various beds thereof, which beds may be even 
at a considerable height in that formation. 
In the Co. Kilkenny, to the N.E., of Thomastown, the “ Old Red 
Sandstone” comes in as a distinct subdivision at the base of the 
Carboniferous Limestone and increases in thickness as it is 
followed to the 8.W., still retaining this relative stratigraphical 
position. 
But N. of the line joining Dublin and Galway the small ex- 
posures of so-called “ Old Red Sandstone” appearing through the 
* In the Glengariff Grits, the Dingle Beds, the Toormakeady Conglomerates, the 
Mweelrea beds, the Curlew rocks and the Fintona rocks, there are peculiar and charac- 
teristic felstones and traps that seem to be all of nearly the same age. 
+ As the Continental and American Geologists find plants apparently of Carboniferous 
typesin the typical Silurians, this evidence against the Silurian age of the Dingle and 
Glengariff beds is, at least in part, done away with. 
