26 IRISH MINERALS AND BUILDING STONES. 



mingled green and red. The green colouration, being largely due to 

 epidote, implies, in this case, a general hardening, and not a softening of the 

 mass. These handsome rocks, like those of Mayo and Donegal, lie near the 

 coast, whence cheap carriage might be available. 



The granites of Donegal have been worked from time to time, and a 

 company is at present engaged on those around Dungloe. The rocks here 

 offer great variety of colour, a consideration of much importance, seeing how 

 often red and grey stones are used in the same public building. The 

 granite of Tamney, Milford, is also being worked by another company. 



The importance of the granite industry, even in its present position, may 

 be gathered from the fact that 165 persons are employed in the County of 

 Wicklow alone in extracting granite for ordinary building work, fifty of 

 these being at the Ballyknockan quarry, near Blessington. More than 100 

 men are employed in one of the Newry quarries, and fifty in eacli of several 

 others. 



Finally, among stones which pass in the trade as granites, but v/hich 



have a very different chemical composition, the hand- 

 _. , ., some dark-green dolerite of Rostrevor may be cited, 



which is often used for tombstones. The tough 



altered dolerite or fine-grained dolerite, of Arklow 

 provides employment for 1 80 persons, being famous as a material for paving 

 setts. 



In the foregoing sketch of the mineral resources and building stones of 



Ireland, many interesting materials may have been 



„ , . passed over, which may in time prove to have com- 



" mercial importance. But- enough has been said to 



assure the reader that the popular notions as to the 

 vast mineral wealth of Ireland, or her hidden coal-fields, waiting only for 

 development, are myths unworthy of a serious and reflective age. If mining 

 of metallic ores is to be established or revived in any district, it will only be 

 possible through scientific enterprise, on carefully considered economic 

 principles, and, above all, through the hard and continuous work of all con- 

 cerned. It is possible, after all, that a ploughshare and a spade made of 

 imported iron, and a home-bred peasant to guide them, may yet prove the 

 best means of utilising the mineral wealth of Ireland, which ages of denuda- 

 tion have taught us to look for in the soil. 



BIBLIOGRAPHY. 



Memoirs to the Sheets of the Geological Survey of Ireland; various dates. A 

 notice of any mines or trials for minerals usually appears in the concluding pages of 

 each memoir. 



G. Wilkinson. " Practical Geology and Ancient Architecture of Ireland " (Murray, 

 London, 1845). Contains a practical description, county by county, of all building- 

 materials worked in Ireland at the date of publication, with the results of an elaborate 

 series of experiments on the absorption of water by various specimens, their weight per 

 cubic foot, and the weights required to break or crush them. 



Sir Robert Kane. "The Industrial Resources of Ireland" (Hodges and Smith, Dublin, 2nd 

 ed. 1845). This classical work deals with Irish coals in pp. i — 54, metallic xires in pp. 

 118—230 and 245 — 248, and building-materials in pp. 170 — 171 and 230 — 45. 



Jos. Holdsworth. " Geology, Minerals, Mines and Soils of Ireland" (Houlston and Wright, 

 London, 1857). ^ popular account, written when mining enterprise was especially active 

 in the British Isles. 



" Report of the Commissioners appointed to inquire into the several matters relating to Coal 

 in the United Kingdom " (1871), vol. i., pp. 78 and 168 ; vol. iii., pp. 27 and 150. 



Ed. Hull. " The Coalfields of Great Britain " (Stanford, London, 4th ed., 1881). Includes 

 Ireland in pp. 322 — 344. 



G. H. Kinahan. " Economic Geology of Ireland." Forms volume viii. of the Journal of the 



