Mineralogy of Sky. 109 



that of Glen Tilt In aspect and composition, renders it probable 

 that like this it lies in mica slate, forming beds parallel to and inter- 

 stratified with that rock : that the others have similar relations to the 

 primary rocks, we should have concluded on general geological prin- 

 ciples, had we not already seen that the white marble of Sky which 

 has given rise to this discussion belongs to the secondary strata. 

 ' We have now to examine the white marbles which have been 

 discovered in our own islands, for the purpose of comparing their 

 relative properties and the value which they are likely to possess 

 in sculpture. I am unfortunately unable to give any account of 

 those found in Ireland, neither having seen their places, nor being 

 possessed of any specimens. 



That which has been found at Cape Wrath in Scotland, is of a 

 grain much larger than even the Parian, and is consequently useless 

 for the purpose of sculpture ; and this indeed is by much the most 

 common character of the Scottish specimens. Those of Blair- 

 gowrie, of Glenavon, and of Balahulish, are all equally charac- 

 terized by this large sparry texture, and are all equally unfit for 

 sculpture, however applicable to the purposes of architecture. 

 The marble of lona has been long since exhausted, and conse- 

 quently requires no particular notice : however valuable from the 

 purity of its colour and compactness of its texture, yet the uncer- 

 tainty of its splintery fracture before the chisel, (that tool without 

 which no spirited work was ever finished,) combined with its great 

 hardness would probably have rendered it useless in the arts, even 

 if it were still to be procured. 



In a paper on Assynt* I have already described the white marble 

 of that district ; it is of a very close texture, and although it con- 



* Vol. 2. 



