W 5 
Geological Relations of the East of Ireland. 
pyrites, and heavy spar; but these are comparatively of rare occur- 
rence, quartz and galena being the principal constituents. 
The connected workings upon this vein extend about 160 
fathoms on its range; the wing of the mine to the right of the 
adit being one hundred fathoms, and that on the left sixty fathoms 
in length. The annual produce of ore, during a course of several 
years, has been from three hundred to four hundred tons of galena, 
which yields on an average 68 per cent, of lead; and it is worthy 
of observation that the vein has proved much the most productive 
in that part, where it traverses a very thick bed of mica slate. The 
ore is smelted in a simple and cheap manner in small blast furnaces, 
with the aid of turf, lime, and a small proportion of the purest 
blind coal that can be procured; and being reduced at a single 
operation, the lead obtained is of an excellent quality, fit for every 
purpose of the plumber. In the adit level, about eighty fathoms 
from its mouth, a vein was crossed about three feet wide, consisting 
of quartz, and containing some disseminated galena and iron 
pyrites. It ranges 20° south of east and north of west, inclining 
toward the north-east. In its progress to the eastward, it would, 
if continuous, traverse Ballinafinchogue vein under an angle of 
45°, about fifty fathoms to the east of the adit; and it appears in 
fact to do so, but in the form of a fissure only, which, however, is 
probably its eastern termination, as it agrees in range and dip with 
the vein in the level. It is very remarkable that beyond this 
fissure the lead vein has proved in a great degree unproductive. 
The lead vein in its progress to the north-west crosses the 
ravine, which we formerly ascended from the smelting-house 
(§31.), and there encounters a strong vein of quartz, containing 
sparingly disseminated galena, which may be traced some distance 
down the ravine, standing like a wall, the decomposed mica slate 
