202 Scientific Proceedings, Royal Dublin Society. 
of Silurian (Caradoc) fossils at Grangegeeth, near Slane, co. 
Meath, and at Tramore, besides Knockmahon, co. Waterford. 
But as those districts had not been yet sufficiently examined for 
fossils he had not marked them as Silurian ; he thought it unwise 
yet to attempt to separate them from the Greywacke. But the 
Dingle Beds and Glengariff Grits, with as nearly as possible their 
present outlines, are made Silurian, instead of mere Newer Transi- 
tion. The Yellow Sandstone which had been supposed to form 
the chief mass of Slieve Baun, co. Roscommon, Slieve Moray, co. 
Galway, the Devil's Bit, and Keeper Mountains, the mountains 
N. and §. of the schistose range of Carn Clonhugh, co. West- 
meath, &., is now made O.R.S. Various other changes were 
made besides these. This map was presented to the Geological 
Society of Dublin, the former being withdrawn at the same 
time. 
In Angust, 1843, the map was exhibited to the British Asso- 
ciation, at Cork. It does not appear that any changes had been 
introduced since 1840, except that the Silurian fossil localities, 
already mentioned, on the coast of Waterford were marked ; but 
in his paper accompanying the map he says that the boundary 
of the Silurian there must be enlarged. He had lately dis- 
covered Silurian fossils at the Chair of Kildare. In the same 
paper he speaks of a change which probably ought to be made, 
but which, in deference to the opinions of certain others, he did 
not make. The rocks of the district on the N.E. side of Lough 
Erne, the centre of which is near Fintona, those of the Curlew 
Mountains, at the northern end of Roscommon, and those of 
Croagh Moyle, &c., near the N. E. angle of Clew Bay, are appar- 
ently of similar though somewhat doubtful age. The Fintona 
rocks had been hitherto classed and coloured as O.R.S., but 
they are apparently conformable with the Silurian at Pomeroy 
and Lisbellaw; and the base of the Carboniferous, consisting of 
red and grey sandstones, lies unconformably upon the Fintona 
rocks. Therefore, those rocks are probably Silurian. The Cur- 
lew Mountain rocks are exactly similar to the Fintona rocks in 
geological position, and in composition and character (in the 
small map of April, 1838, these were coloured as Yellow Sandstone). 
The reddish-brown sandstones and conglomerates at Newport 
(Croagh Moyle district) are similar to the foregoing, and are 
