22 IRISH MINERALS AND BUILDING STONES. 



A. Kinahan* that the deposits were by no means exhausted. Mr. E. St. John 

 Lyburn, A.R.C.Sc.L, in a paper presented to the Royal Dubhn Society in 

 I go I, has proved, by a large number of assays, the general poverty of the 

 Wicklow rocks in gold ; but at the same time he supports Mr. G. A. 

 Kinahan's view that many of the gravels remain unexplored, especially in 

 their deeper layers, or on the shelves above the present streams. t Mr. 

 Gerrard A. Kinahan's paper contains an excellent account of the history of 

 gold-working in County Wicklow, whereby it appears that the value of the 

 metal raised only occasionally exceeded the cost of mining. Probably, the 

 really profitable transactions were those of the peasantry, who from time to 

 time stored up a little gold, which they had washed out by the most primitive 

 means, and brought it for sale to the jewellers in Dublin. It is currently 

 reported that this practice still continues. The gravels to the north and 

 north-east of Croghan Kinshelagh were worked by Government from 1796 

 to 1803, when the operations were finally abandoned. Various companies 

 have examined the deposits since that date, finding gold, it is true, but not 

 with sufficient uniformity. 



The occurrence of Cassiterite (in the form of stream-tin), with its constant 



associate wolfram, in the auriferous gravels of Croghan 

 Tin. Kinshelagh, has also excited curiosity. This instance, 



and the finding of a small quantity of tin ore in a lead- 

 vein at Dalkey, are the only authenticated records of cassiterite in Ireland. 

 In County Wicklow the original vein has not been discovered. 

 Among minerals which are not metallic in the popular sense, Rock-Salt 



deserves the most prominent mention. The well- 

 Rock-salt, known beds near Carrickfergus, in County Antrim, 



were discovered in 1850, when the Triassic clays and 

 sandstones were being pierced in the hope of finding coal. The site offered, 

 in reality, only a very small chance for the coal-prospectors ; but the borings 

 proved the existence of deposits of rock-salt comparable with those of 

 Cheshire. One of the beds at the Duncrue mine was actually eighty feet in 

 thickness. The records show that 32,113 tons of salt were raised from this 

 limited area in the east of Antrim in 1900, with 1 1,081 tons obtained in 

 addition from brine. 



While the Gypsum associated with the same strata near Belfast is mostly 



in thin veins, this mineral has been worked, for the 

 Gypsum. preparation of Plaster of Paris, from a much thicker 



mass in the Triassic outlier near Carrickmacross. 

 Barytes, another white salt, occurs in veins in many places, as in the 



Ordovician strata of the coast of County Dublin ; 

 Barytes. but in County Cork it is of unusual mass and abund- 



ance.+ Near Bantry, a vein is found from ten to 

 fifteen feet thick ; and a remarkable lode, like the infilling of a chimney, 

 thirty feet long and fifteen feet wide, also occurs. Barytes is mined at 

 Mount Gabriel, near Schull, at Duneen Bay, Clonakilty, and also at Gleniff 

 near Bundoran. 3,278 tons of barytes were raised in Ireland in 1899, and 

 3,626 tons in 1900. The material, it may be observed, is mined to a yet 



* " On the Mode of Occurrence and Winning of Gold in Ireland," Journ. R. Geol. Soc. !• 

 vol. vi. (1882), p. 156, and also in Sci. Proc. R. Dublin Soc, vol. iii. (1883), p. 263. 



t Sci. Proc. R. Dublin Soc, vol. ix (1901), p. 426. See also a paper by Mr. George H. 

 Kinahan, ibid., vol. iv. (1885), p. 39. 



J See E. T. Hardman, " On the Barytes Mines near Bantry," Journ. R. Geol. Soc, I., vol. v. 

 {1878), p. 99. 



