Geological Relations of the East of Ireland. 199 
fathoms in length, and in the deepest part 22 fathoms, at “which 
depth the northern vein is about 3{ fathoms distant from the 
southern vein. They had been pursued into the mica slate about 
10 fathoms only. Their most productive part was at the place of 
meeting, near the surface. The north vein varies in width from a 
few inches to one and a half and two feet, in some places enlarging 
to the breadth of four or five feet ; and on this the deeper workings 
have been conducted, the south vein being less productive of ore, 
and in general only from a few inches to one, or one foot and a half 
thick. The veinstones are quartz and heavy-spar, which bear ore 
in short bunches from a few inches to one and two feet in width, 
and in length from one to three feet, consisting of fine grained 
galena, which yields 75 per cent, of metal, accompanied by some 
white lead ore, and occasionally by blende and pyrites. 
§ 92. To the west of Lough Dan is a vein which traverses the 
granite brow of CarriggeendufF, (§ 26.) and, ranging across the valley, 
penetrates KnocknacloughoJe mountain on the north. It has been 
opened by two levels near the northern foot of the former mountain, 
one about fifteen fathoms above the other, and forty-eight and thirty- 
six fathoms in length respectively. The vein is in general from three 
to four feet wide, and dips 80° toward the east, consisting of quartz, 
with a regular sticking or layer of soft tenacious clay (the German 
hesteg) on the western side, and containing galena either in bunches 
or disseminated, and occasionally also a small quantity of copper 
pyrites; but the greater part of it, as far as explored, appears to be 
barren. This vein does not seem to penetrate the mica slate, which 
to the southward forms the upper part of CarriggeendufF; four 
trenches cut into that rock in search of it, ten fathoms asunder, and 
across the direction of the vein, not having been attended with 
success. 
