138 
JOURNAL OF THE GEOLOGICAL SOCIETY OF DUBLIN. 
of a grayish-white sandstone, which bed, two or three feet thick, I 
believe is in the brownstone strata; and I have seen plant remains 
in a similar bed, and in a similar geological position, at Knocka- 
havann, two miles N. E. of Dungarvan. We had also some of the 
same kinds exhibited here last year, by Dr. Griffith, from Tallow 
Bridge, to illustrate his paper on the Yellow Sandstone, which the 
Society may remember; but neither the sandstone nor the plants are 
like those that occur in the Carboniferous rocks,—the Lepidoden- 
drons and Catamites being of a stunted growth, and different species. 
Professor Rogers produced specimens of plant remains at the last 
meeting of the British Association, at Glasgow, identical with those 
got at Tallow Bridge; and he put them forward as having been 
found in some of the Silurian rocks of America, and exhibited them 
as geological curiosities, plants of Silurian age. 
I have thus endeavoured to show, that in our Irish Palaeozoic 
rocks there are two old sandstones which belong to two distinct 
eras in the history of the earth,—the first, being the lower and the 
older, is of a brown or reddish-brown colour, and is composed both 
of grits and slates, the grits very hard, and the slates having a 
strong cleavage. Moreover, that in the south and west of Ireland, 
where those rocks are pretty fully developed, the brown and red 
grits and slates alternate with green and gray grits and slates of 
the same age; that in Kerry, those rocks amount in one section to 
above eleven miles in direct thickness, without the upper or lower 
beds, which are invisible; that they include bands teeming with 
fossils of the Silurian age, and that the beds usually dip at a very 
steep angle, except in the tops or bottoms of some of the great con¬ 
volutions which occur occasionally in parts of the countrythat 
the second or upper part of those sandstones is that band which forms 
the base of the Carboniferous rocks; it is more red, more soft, and 
thinner, its average thickness being about one thousand feet. It 
contains no green or gray grits or slates, and very seldom exhibits 
cleavage in its shales, only lines of lamination: the beds generally 
lie flat, or nearly so, and these are features affording some points 
of contrast when compared with the older rocks. 
The Devonian rocks are said to constitute a passage, or gradual 
change, from the Silurian into the Carboniferous formation, and to 
partake of the nature of both, in fossils, as well as in rocks. I have 
given a list of seventy-eight localities, any of which may be visited 
—and stated that I know many more where the Old Red Sandstone 
