396 Scientific Proceedings, Royal Dublin Society. 



In the list will have to be mentioned rocks that are not at 

 all likely ever to be of commercial value as marbles. This, how- 

 ever, appears necessary, as some of them have already been given 

 a greater value than they deserve ; and, on this account, it is desir- 

 able to mention them. 



All of these stones, that are also suitable for cut-stone purposes, 

 are a second time mentioned in the lists of the limestone quarries. 



METAMORPHIC LIMESTONES. 



The rocks that come under this class — with the exception of 

 the peculiar Sienna-coloured stone in Grlendowan, the black stones 

 from near Rathmullen, Co. Donegal, and those of Carricksheedy, 

 Co. Londonderry — are white, or shades of white, some handsome 

 stones being tinted or clouded with grey, pink, or green. All are 

 more or less schistose. Some are thin-bedded, those that are 

 massive generally rising in more or less rude, unshapely blocks. 

 The stones are for the most part coarsely crystalline, and conse- 

 quently not able to compete with the Italian stones ; while those 

 of a creamy character, as far as has yet been discovered, are also 

 disqualified, owing to their being either too thin-bedded or jointy, 

 which prevents them being raised in blocks of sufficient size. 



On this account many hand-specimens show a beautiful stone 

 equal to any elsewhere ; while, in the quarry, these stones are 

 found to be of such small dimensions as only to be suitable for 

 the manufacture of artioles of vertu. 



This to me seems a most important fact, to which too much 

 attention cannot be directed in Papers on the Economic Greology 

 of the country. 



What might be highly productive industries have been already 

 destroyed by false statements in reference to them. 



