80 Scientific Proceedings) Royal Dublin Society. 



since his time very little has been done. The Devonian slates of 

 green and red colours, that ought to be valuable for ornamental 

 purposes, have been very little used. These usually occur on a 

 well-marked horizon, at the junction of the Yellow and Old lied 

 Sandstones. At Brow/tead mine, and between Horseshoe Harbour 

 and Barrackpoint, they were worked for local purposes. The 

 slate at the S. E. corner of S/wrkin Island, Baltimore Harbour, has 

 been highly approved of, and sometime since a Company was formed 

 to work this vein ; but for some unknown reason the enterprise was 

 abandoned. At Cappoge, west shore of Roaring Water Bay, there 

 is a purplish blue slate well suited for slabs. In different other 

 places the slate veins have been opened for local purposes ; but 

 more often to obtain slabs than roofing slates. 



The Carboniferous dark-grey and blackish slates have been 

 more worked of late years than the others. One quarry is at 

 Rossmore, about a mile W. S. W. of Fourmile Water ; farther 

 south westward, near Kilcrohane, there are quarries in the town- 

 lands of GortaJcilly, Gouladoo, and Foila/eilly, the slate being of 

 better quality than at Rossmore, besides being near a harbour ; 

 these slates have been worked only for local purposes. Grey slate 

 has also been worked N. W. of Dromdaleague, Curraghlichy, Ennis- 

 Jceen, Bandon, and Clonaldlty ; but the most extensive quarry from 

 which slates are exported is at Benduff, two miles N. W. of 

 Eosscarbery, on the road to Leap. Here the vein is about seventy 

 yards wide, and of a very dark-grey colour. In places in the slate 

 there are small specks and veins of pyrites (rucks), nodules (bulls' 

 eyes), and a curled structure in lines called cullheads ; all of which, 

 when they occur, deteriorate the slate. Slabs for flagging have 

 also been raised here, and were used in Skibbereen and elsewhere. 



DONEGAL. 



In this county there have been many trials for slate, but only 

 in a very few places is the quality and quantity sufficient to make 

 it worth while opening a quarry. The following is a list of the 

 principal places : — 



Duniviley, a mile and a-half from Stranorlar ; half a mile from 

 Letterkenny, and about the same distance from Lough Swilly ; 



