RESEARCHES AMONG THE PALAEOZOIC ROCKS OF IRELAND. 127 
for, the Carboniferous Old Red, which I have been describing. It 
is of true Silurian age, as I shall presently show. It is awkward to 
have two or three rocks, of two or three geological epochs, bearing 
the same name, Red Sandstone. This rock occurs in four or five 
other parts of Ireland, but it especially prevails in the south, where 
it is called by the peasants “ Brownstoneand as this appears an 
appropriate name, for colour at least, I adopt it, for sake of distinc¬ 
tion, as a Silurian rock. 
At Ferriter’s Cove, on the coast, eight miles N. W. of Dingle, a 
band of gray slaty rock dips S. E., at an angle of about 70°, and is 
full of Silurian fossils. This band, from Doon Point, its N. W. ex¬ 
tremity, across the strike, is about half a mile wide on the surface,^ 
or at this dip 2500 feet in thickness. A band of brownstone strata 
underlies this fossiliferous band, north-westwards to Sybil Point; 
where the Old Red Sandstone of the Carboniferous System covers it 
unconformably, dipping N. W. 60°. From the signal tower on the 
conglomerate, across the strike of the brownstone, to the fossilife¬ 
rous slaty band, is 60 chains, and this, with a dip of 70°, gives a 
thickness of brownstone here of 3600 feet. The section is well ex¬ 
posed on the coast near Sybil Head; but the bottom of it is not seen, 
being under the sea level. The geological position of this brown¬ 
stone is fixed, by its being found conformable with, and under, the 
Silurian fossiliferous band. 
At Clogher Head, farther south on the coast, a greenstone pro¬ 
trusion interferes with the continuity of the strata; but in the 
stream near Doonquin old churchyard, six miles west of Dingle, a 
fossiliferous slaty rock, similar to that at Ferriter’s Cove, dips south¬ 
ward, and is covered by brownstone and brown slate, alternating 
with green grit and green slate to Slea Head—a distance of nearly 
two miles and three-quarters: all dipping at a steep angle south¬ 
wards, and conformable. This, at an average dip of 70°, would 
give a thickness of about 14,000 feet of those grits and slates over 
the fossils at Doonquin,—all part of the same system. 
I have just said that the fossiliferous band at Doonquin appears 
similar to that at Ferriter’s Cove. They are separated by some grit 
beds, and a greenstone protrusion; but, nevertheless, they may be 
parts of the same original band, and accounted for thus:—In the dia¬ 
gram which I now exhibit, suppose the earth’s surface at this locality, 
at one time, to have stood at a higher level, shown by the dotted line 
