94 REPORT—1857. 
from an outlier of the coal-measures on the south, through the carboniferous lime- 
stone, Old Red Sandstone, and Silurian, to the limestone of the Glen of Aherlow on 
the north. ‘This section may be regarded as typical of the geological structure of the 
lofty range of the Galty Mountains, among the highest in the south of Ireland, reach- 
ing an elevation of 3014 feet above the sea. The Lower Silurian, occupying chiefly 
a large hollow in the centre of the range, surrounded by hills of varying height, cap- 
ped with the lower conglomerate of the Old Red Sandstone, is composed of dark- 
coloured green, olive, red, and pnrple slates, grits and gritty sandstones generally 
striking in a nearly east and west direction, dipping at high angles, sometimes to the 
north, sometimes to the south, and often much contorted. Upon and unconformable 
to it rests the Old Red Sandstone, which, from previously existing irregularities in the 
surface of the Silurian, or from other causes, seems to have been very unequally depo- 
sited, as seen by referring to the section, where this formation is represented on the 
north by somewhat less than half its thickness to the south. It frequently presents fine 
examples of oblique lamination ; and the only traces of organic life met with in it were 
some small markings of two kinds, probably annelid tracks, or fucoids, in beds of fine 
red sandstone, near the base of the formation, specimens of which were exhibited. 
The basal bed of the Old Red Sandstone is generally a thick soft conglomerate formed 
of red grit, pebbles, and fragments of the Silurian rocks in a purple paste, with very few 
pebbles of quartz... This character is not, however, constant, for it is sometimes found 
to be a green breccia with some rounded fragments of purple grit, and sometimes a 
few beds of red sandstone intervene between the conglomerate and the Silurian. 
Further up in the formation, at about half its thickness, occurs another marked band 
of conglomerate, the space between it and the basal one being occupied by red grits 
and sandstones. It is in one place 400 feet thick, and its pebbles are chiefly of quartz 
in a purple paste. Small and much rounded pebbles of syenite and trap are also found 
in it, as well as some fragments of green and grey grit. Above this are more red 
grits, becoming paler as they approach the top, and having bands of liver-coloured 
shale, interstratified with yellowish and coarse grey and greenish sandstone. At about 
1200 feet above the last-mentioned conglomerate occur certain beds of purple ferru- 
ginous sandstone, having, when weathered, a pitted appearance. Immediately above 
them the author draws the very arbitrary boundary of the yellow sandstone, which, 
on the southern slopes of the Galties, may be about 1200 feet thick. There are just 
traces of some dark green gritty shales appearing in one or two places, which are pro- 
bably the representatives of the carboniferous slate. The apparent thickness of all the 
Old Red, including the Yellow, Sandstone on the south side of the mountains may 
be in different places from 4000 to 4500 feet, while on the north side it is only 2000 
feet thick. The carboniferous limestone is almost quite concealed by drift, and when 
seen is grey, compact, and sometimes slightly crystalline, containing corals and other 
fossils, but the Calp division does not appear. Upon it lies a thin outlier of the coal- 
measures, seen at the south end of the section, consisting of the lower black carbona- 
ccous shales and thin olive grits, in which a shaft was sunk with the hope of finding 
culm; but the limestone was reached without success, and the search was then aban- 
doned. 
On the Tertiary Clay and Lignite of Ballymacadam, near Caher, in the 
County of Tipperary. By A. B. Wynne. 
This clay is found under and about the ruins of the old castle of Ballymacadam, 
of which little more than the foundations now remain. The mode of its occurrence 
is very strange, for when standing in the centre of the small hollow which it occu- 
pies, at a distance of about 100 yards, on almost every side the carboniferous lime- 
stone may be seen to protrude through the ordinary drift which is spread over the 
surrounding country, and which most probably once covered this isolated basin of 
tertiary clay, occupying an area of at the most about an acre anda half. Man 
pits have been sunk within this limit, of which three or four are visible, now filled 
with water; one small one has been recently opened to the depth of four or five feet, 
and in this, in situ, was found a lenticular mass of lignite, a specimen of which is on 
the table. The clay is usually white, more or less pure, and sometimes of a dun or 
bluish tinge, smooth to the touch, and extremely tenacious. The lignite is brown, 
