194 Scientific Proceedings, Royal Dublin Society. 



[These qualifications of schistose, slaty, and shaly rocks can be studied in various places 

 round the coast of Ireland. On natural sea-margins the waves rise much higher on a 

 smooth surface than on a rough one, or on a perpendicular wall than a sloping one. A 

 wave coming on a rock will rise much higher than on an adjoining shingle beach, and 

 on a perpendicular rock-cliff much higher than on a sloping one. This, of course, is 

 intended to apply only to more ordinary cases. If a sea-wall rises directly from water 

 so deep that there is but little breaking of the wave-crests above it, the face of the wall 

 should be perpendicular. This is well illustrated when a north-easterly storm is driving 

 the waves against the perpendicular rounded end of the west pier of Kingstown 

 Harbour.] 



WICKLOW, KILDARE, AND CARLOW. 



Introduction respecting Granite. 



[The granites of the north-west of the granite area, situated in Co. Wicklow 

 (Blessington district), are much preferred by the Dublin builders to those of their own 

 county, as not only are the stones kinder to work, but also, as pointed out by 

 "Wilkinson, they are wrought on the spot by native stonecutters, thus saving expense 

 in various ways. "We may again point out, on account of its importance, the advan- 

 tage of cutting building stones at the quarry. The stone can be cut more easily and 

 cheaply when fresh than afterwards. The carriage to be paid for is solely that of the 

 wrought stone, and not of blocks, a fourth or a third of which ivould have to be chipped away 

 afterwards, while only sound stones are sent from the quarry. On the other hand, 

 if the stone is sent in blocks, notwithstanding the most careful selection, some bad ones 

 will escape detection ; and these, after their carriage, will have become so costly that they 

 cannot be thrown aivay, and have to be used to the detriment of the building. 



In the neighbourhood of Castledermot, Co. Kilda'-e, and in the western part 

 of the Carlow granite tract, the rocks are partly similar when sound ; but in places 

 tracts of growan come in. Some of this growan probably belongs to the newer granite ; 

 but a large portion is evidently disintegrated "Leinster type" (Haughton) granite. 



At the junction of Carlow and"Wicklow, near Shillelagh, in the district after which 

 it may be called, is the Aughoiule peg maty te. This peculiar variety, already described 

 (ante, p. 182), is so coarse and unsightly as to be suitable only for the very roughest 

 field walls.] 



Iii Kildare and in Carlow, both on the granite and' on the 

 marginal tract of schist, there are many granite erratics, now far 

 less numerous than they were some years ago. These were 

 formerly a considerable source of income to the occupying tenants, 

 who split them up, and wrought them into pillars, earth-rollers, 

 sills, window-stools, &c, or sold them to the stone-cutters and 

 builders, who wrought them themselves. This trade, however, has 

 greatly fallen away of late years, iron articles being used instead 

 of stone in so many cases. The length of scantling supplied by 

 these stones, and the long bearings of which they are capable, 

 even with small transverse dimensions, are very remarkable. 



