20 
PROCEEDINGS OF SOCIETIES. 
times rather friable and earthy, appearing like a somewhat decomposed 
mixture of granular feldspar and quartz. The larger mass was a dis¬ 
tinctly crystalline aggregate of feldspar and quartz, with, in some parts, 
small crests and little detached flakes of white or green mica. It thus 
formed a perfect granite occasionally, though its general appearance in 
the quarry was hardly that of true granite, and it required a close in¬ 
spection of a fresh surface to assure one’s self that it was so. It was much 
jointed in many directions, hut large euboidal blocks were not unfre¬ 
quent. When broken open, these were often seen to show signs of 
weathering internally to a depth even of eight inches or a foot, and 
even when taken from the heart of the quarry. The central nucleus 
or core of these blocks was a pale greenish-gray, while that core was 
surrounded by bands of yellowish and reddish-brown, conforming in 
outline to the external margin of the block, and getting darker as they 
approached it. This is a very common character in most of the elvan 
dykes of Wicklow and Wexford, but is one that is not so often seen, 
scarcely ever to the same extent, in larger masses of true granite. Is it 
owing to the presence of iron, or some other ingredient which the veins 
have derived from the masses of other rock which they traversed ? 
About thirty yards east of the quarries in this Granite or Elvanite, 
blocks apparently in situ appeared above ground of a totally different rock. 
This was a highly crystalline greenstone, with tabular crystals of feld¬ 
spar, sometimes half an inch long, but generally smaller, though still 
distinct, and of a white or pale-green colour, interlaced with crystal¬ 
line granules of dark apple-green hornblende, and a black lustrous mine¬ 
ral, which is probably another variety of hornblende. Yellow iron 
pyrites also occurs in small cubical crystals. It was intensely hard, and 
the blocks were so massive, and weathered into such rounded forms, that 
it was impossible to detach any but small chips from them. A few yards 
east of the line in which these blocks occurred, the greenstone appeared 
to become of a finer grain as it approached the slate. The slate itself 
near the greenstone was very hard, and had a flinty appearance, pro¬ 
bably due to the influence of heat; but this only extended for a few 
feet, the mass of the slate being quite unaltered. 
After crossing the slate ridge to the east, crystalline greenstone again 
appeared, occupying all the south-eastern slope of the hill of Eock 
Little, and there was one narrow belt of ground running across the 
strike of the slates, in which no fragments of slate were to be seen at the 
surface ; but blocks of greenstone did appear. It is possible, then, that 
here was a greenstone dyke cutting across the slate, and connecting the 
greenstone on the east with that on the west. If so, it must be very 
narrow, not more, certainly, than ten yards, as slate appeared again in 
mass immediately to the north-east of this band. 
This greenstone, which occurs in considerable mass on the south-east 
of the hill of Eock Little, continues down into the small valley which 
runs between Eock Little, and Eock Eig, and the first rock seen after 
crossing that valley is also greenstone of a similar character. It is pro¬ 
bable, therefore, that the valley has been excavated in the greenstone, 
