212 Scientific Proceedings, Royal Dublin Society. 



Outside this oval, in places, to the south, are intrudes of elvan, 

 with, near Castle Farm, a peculiar felstone, having, in places, an 

 aspect like trachyte ; while to the northward, at Maddyboy, there 

 is a boss of elvan. In the north part of the county there are 

 small detached exposures of tuff, euryte, and whinstone, to the 

 south of Castleconnel, at Knockbrack, Limerick, Carrigogunnel, 

 Kilpeacon, Eosborough, and Caharny, with smaller ones to the 

 west, near Shanagolden. 



There seem to be either intrudes, or protrudes of a rock that is 

 apparently euryte (Daubuisson), around which the sandstones ac- 

 cumulated. They are quarried for rough walling and road metal. 

 In the eastward part of the county, in the Bilboa Eiver, near Doon, 

 there are felstone dykes. 



None of these rocks have been much utilized. In the neigh- 

 bourhood of Limerick there are some considerable quarries in the 

 tuffs, which are used for road metal and general walling purposes. 

 For the latter they are eminently suitable, as they rise in flat- 

 bedded, well-shaped blocks. In the new railway station, and in 

 some other buildings in Limerick, they were used for quoins and 

 facings. Generally throughout the country in which the exotic 

 rocks occur they are only quarried for local purposes, principally 

 for road metal ; but for the latter purpose many of the quarries 

 are in the tuffose rocks or limestone, and not in the more durable 

 whinstone. Many of the elvans rise in ill-shaped blocks ; but this 

 is not so in the quarry near Caherconlish, where nice stones of fair 

 scantling can be procured. 



Small pieces of the following rocks have been cut and 

 polished : — 



Killeena, Co. Limerick. Eed porphyry, with salmon-coloured 

 and blackish spots ; cuts and polishes easily, but shows verts. 



Knocltroe, Co. Limerick, S.E. end of boss. Very similar to last 

 in colour ; cuts and polishes easily, but shows verts. 



Knocltroe, centre of boss. A handsome porphyry ; purplish, 

 with red and white spots ; cuts and polishes well. 



Knocltroe, at outside of boss. Striped purplish ; cuts and 

 polishes well. 



Long Stone, Co. Tipperary. Buff, porphyritic ; cuts and 

 polishes well. 



