306 On the Geological Structure 



boundary of the granite on its northern and western confines 

 is much less regular than on the cast; it probably com- 

 mences on the shore of Dublin bay between BooterstoivndiX\d 

 Blachock, a mass of limestone having been observed there 

 within a short distance of granite, but the rocks are con- 

 cealed in the intervening space. 'J he granite comes nearly 

 into contact with limestone again, near the junction of the 

 stream from Dundrum with the river Dodder a little above 

 the village of i\7;7//o«'n; and is visible near schistose beds 

 in the course of ihe streamlet between IVkitechurch and 

 Eathfarnham. It has been observed in contact with schist 

 to the west of llie Glen near the head ot the Doddery 

 pearly opposite to a little village called the Brakes of Glass- 

 namiicky, but from that place to the west and south, the 

 line of boundary has been very little explored : it passes 

 however very near the granite quarries at Golden-hill, and 

 must run to the east of Poula P/mca and the Glen of Hohj^ 

 wood. A junction occurs at Ballyroan on the south-west- 

 ern side of KUranelagh-kill ; and granite has been observed 

 in that neighbourhood, to the ea?t of Kilranelagh at Knocka- 

 devry, and to the south of it at Killalish, Kiltegan, Kilma- 

 cart, and near the town of Carlow where the limestone 

 appear^, at Brownshill. 



The slaty rocks incumbent on the granite in this country 

 are very much diversified in their nature, and they have 

 hitherto been very little examined. On its eastern confines, 

 in the places above-mentioned, the prevailing rock is mi- 

 ca slate, the beds of which in general lean towards the 

 frranite, their direction being nearly parallel to the line of 

 junction : rocks of the trap kind occur to the west in the 

 neighbourhood of Balllnascorney, and at Kilranelagh ; and 

 columnar rocks of the same description have been observed 

 at Arklow-rock on the south-eastern extreniity of the county 

 of Wicklow. 



The country around the village of Bray, which, like that 

 of Wicklow in general, is remarkable for the picturesque 

 beauty of its scenery, presents within a small space several 

 vrrv interesting geological appearances ; and those observa- 

 ble'at Killiney, first noticed I believe by Dr. Blake of Dub- 

 lin, will he found particularly deserving of examination : 

 the line of junction, which, as already mentioned, hasbeen 

 traced for several miles across the country, commencing on 

 the shore at the base oi KiUiney-hill, where schistose beds 

 are to be seen to a considerable extent^ reposing upon gra- 

 nite. 



On the shore from thence to Dalkcy, the granite is tra- 



versecl 



