14<J 
Geological Relations of the East of Ireland \ 
4 . 
5. 
a 
7. 
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9. 
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12 . 
Mica slate and granite, forming an indistinct intermixture 6 fath. thick, 
N. B. The preceding beds include also frequent thin layers of quartz. 
A body of granite, the lower part of which is most curiously interwoven 
with contemporaneous veins of granite and quartz 15 fathoms thick 
Then mica slate ....... 77 fathoms — - — 
Repeated alternations of granite and mica slate, 
forming a body . . . . .22 fathoms 
Mica slate ........ 62 fathoms 
Granite ........ 1 fath. 3 ft 
Mica slate . . , . . „ . 20 fathoms 
Granite .5 fathoms 
N.B. The general character of the upper beds of granite is that of 
granular quartz with much silvery mica, and very little felspar. 
Hence for 50 fathoms up the ravine, mica slate alone is traceable; and 
again for 65 fathoms higher, up to the cattle pond, the same rock 
is still perceptible ; and thus, Lugduff appears to be constituted to 
the very ridge of the mountain, through an ascent of about 120 fath. 
more. 
§ 32. It is many years since I discovered both grenatite and 
emery in this ravine. Some of the mica slate contains a vast quan- 
tity of this substance, particularly the bed I have marked No. 8 f 
generally in very small crystals, but I possess a few groups of 
large cruciform and stelliform crystals, well displayed in alto relievo 
on a tablet of the rock, by the wasted state of the surface. Of the 
emery 1 only met with a loose rounded stone, and I have not suc- 
ceeded in discovering it in situ f though it is probably to be found 
imbedded in the mica slate. 
§ 33. The relations of the rocks at Ballinafinchogue lead mine 
are equally interesting to the geologist and miner. The adit 
which unwaters and ventilates the mine, pierces the vein at a dis- 
tance of 141 fathoms from the valley, and at a depth of 85 fathoms 
from the outburst of the vein at the surface ; and with the sub- 
sequent operations carried on in the right and left wings of the 
