240 Scientific Proceedings, Royal Dublin Society. 



rocks and gneisses are best suited for coarse, heavy work, as piers, 

 sea-walls, and such like. However, a few were observed to be more 

 or less regularly- jointed, and to rise in naturally square blocks. 

 These ought to be suitable for the large setts used in street -crossings, 

 as on account of the difference in the hardness of their mineral 

 constituents they wear rough. 



Kinder varieties of the hornblende-rock, which are generally 

 more or less ophitic, or epidotic, have been noted as beiug very 

 similar to some of the " Swedish green granite" now in the London 

 market; these, therefore, should be capable of being utilized for 

 ornamental and monumental purposes. As, however, up to the 

 present time, no quarries have been opened, it is not possible to 

 give information as to the size and shapes of the blocks that could 

 be procured. We can, however, state that some hand-specimens took 

 an excellent polish, and were of a bright olive-green colour. 



Homhead. About two miles from Dunfanaghy. — Greenish; 

 crystalline ; slightly foliated ; used locally. 



Goldrum. S. W. of Lough Salt. — Green ; slightly ophitic ; 

 can be raised in fair-sized, rather even-shaped blocks. Slabs of 

 this stone were used in some of the old structures of the vicinity, 

 and as farm-fences. 



The hornblendytes are, in places, favourably reported as 

 building material. According to Wilkinson, they were extensively 

 used in Grlenties. Some varieties, however, are inclined, on ex- 

 posure, to become " iron-masked." 



Schist. 



The micalytes, phyllytes, and sericytes are very much in 

 request for general building purposes in the districts where they 

 occur, and even outside them, as they rise in flat-bedded, suitable 

 stones ; while in some places they are regularly jointed, and rise 

 with natural faces. According to Wilkinson they are most durable. 



Those in use, are, however, often badly selected ; some of them 

 are highly ferriferous, and if used as building-stones, the iron rapidly 

 decomposes, and the stone becomes "iron-masked," giving the 

 structure in which it was used an unsightly, rusty apjiearance. 

 Among other places that might be mentioned, the use of badly- 

 selected schists is very well illustrated at Ardara, and its neigh- 



