SANDSTONE OF THE WESTERN COAST. 97 



sandstones. Thus, on Kea cloch, it contains the white 

 spots and stripes of the variegated sandstones, and a 

 mottled variety is also found in the Ben derigs. Where 

 the felspar is abundant, it sometimes becomes white to 

 a certain depth from the surface, examples of which occur 

 in Tanera. In no instance have I observed it to contain 

 mica, nor, with the exception of red jasper and that of 

 the schist just mentioned, any substances but quartz and 

 felspar. In a few instances where the fragments are . 

 angular, the mixture is so condensed that it can scarcely 

 be distinguished from granite. In others, equally rare, 

 it is so soft as to admit of being wrought as a freestone ; 

 but this condition seems always to exist within a small 

 depth from the surface. With an exception which was 

 formerly noticed under the article of Lewis, it is perhaps 

 worthy of remark that in no instance hitherto it has been 

 found to contain imbedded limestone, an occurrence very 

 common in the red sandstones of later origin. None 

 at least fell under my notice throughout the whole of 

 that extensive tract which reaches from Loch Carron to 

 Cape Wrath. 



With respect to the position which the several varieties 

 hold toward each other, it must now be remarked that 

 the coarser are irregularly intermixed with the finer in 

 almost every place where they occur; so that no rule 

 respecting their relative positions can be given. The 

 only exception exists in those cases where this rock is 

 in immediate contact with the gneiss, and in an un- 

 conformable position to it. Here the conglomerate 

 alone is found for a certain space upwards in the order 

 of the beds; consisting of fragments, very slightly altered 

 in form, united by the smallest possible quantity of sand 

 and finer materials, and always appearing to be portions 

 of the rock immediately subjacent. In all other cases the 

 beds of fine and of conglomerated structure alternate in an 

 uncertain manner, or the same bed presents in different 

 parts, differences of composition in this respect. It is 



VOL. II. H 



