IRISH MINERALS AND BUILDING STONES. 25 



are the red varieties of County Cork. The rock of Little Island is the 

 richest in colour, showing, on polished surfaces, a brecciated structure, with 

 flowing lines and veins. It has been largely used for columns and the panel- 

 ling of walls. Red marbles, merging into grey with pink calcite veins, are 

 quarried in the same county at Midleton and near Fermoy. These are all 

 cf Carboniferous age, and possess a beauty similar to that of the Devonian 

 marbles of the Plymouth area. 



The white and grey marbles of the County of Donegal have been 

 examined by prospectors from time to time. Many are true calciphyres, 

 containing silicates developed in them ; or they possess numerous micaceous 

 partings, which hinder their use in large blocks, owing to the planes of 

 weakness thus established. There is, however, a possibility of raising stones 

 of sufficient size in the deeper parts of certain quarries. It must be borne in 

 mind, however, that the metamorphic action and earth-stresses that have 

 affected the whole County of Donegal have converted almost every material 

 alike into schistose masses traversed by an immense number of joint-planes. 



The absolutely unique green marble of Connemara has been much sought 

 after for decorative use. It varies greatly in texture and colour, and is 

 mineralogically unsuited for out-door work ; but its very irregularity and its 

 banded structure render it one of the noblest of indoor ornamental stones. 

 Under the name of " Irish Green," yellow-green stones from Ballynahinch, 

 and magnificently tinted and striped masses from Lissoughter, have been 

 sent to all parts of the world. In common with other well-known types of 

 Irish marble, this material is finely displayed in the decorative work of the 

 Museum of Science and Art and the National Library in Dublin. It owes 

 its special colouring to the serpentine which permeates it in knotty bands 

 and curving layers. This mineral has doubtless arisen from the alteration 

 of olivine ; and the rock probably at one time resembled the banded olivine- 

 marbles that are produced by the contact of lava and limestone in the vol- 

 canic vent of Vesuvius. 



The great demand for ornamental stone that will resist atmospheric in- 

 fluences in industrial cities has drawn especial atten- 

 p ., tion to granite and allied igneous rocks. Granite has 



long been used as a building material in Ireland ; the 

 grey muscovite-granites of the Leinster chain thus 

 furnish the basement-courses of hundreds of unpretentious houses, which 

 are continued upwards in ordinary red brick. Polished granite, however, 

 has proved itself to be the handsomest and most durable material for city 

 work. The transformation of London facades in the last thirty years testi- 

 fies to the prevalent tendency among architects and the merchant-princes 

 whom they serve. In London, which is naturally the purchasing centre 

 towards which Ireland must chiefly look, the grey granite of Aberdeen, the 

 red and uniformly grained granite of Peterhead, and the speckled por- 

 phyritic red graniie of Shap, have been used with a repetition that has 

 almost begun to pall. Swedish and other granites have been introduced to 

 give variety, and many among these importations are granites only in the 

 liberal and commercial acceptance of the term. The fine-grained grey 

 granites of the Newry axis, quarried at Altnaveigh, Moor, Goraghwood, 

 Bessbrook, and other places, have successfully held their own in the London 

 market ; but rich stores of red and variegated granite remain still practically 

 undeveloped in the west of Ireland. Notable among these are the Galway 

 granites, now quarried at Shantallow. Besides a compact chocolate-red and 

 speckled type, porphyritic granites occur, with red felspar in a ground of 



