of Granite and Sandstone in Sutherland, 281, 



same blue and purple greywacke shales. In some places, the 

 schists predominate; in others, the sandstones. 



This, however, is not the order of succession every where. 

 In many parts of the junction there are found conglomerates 

 of various kinds, but generally of a moderate-sized structure, or 

 consisting of small fragments. The first of these to be men- 

 tioned, consists of quartz and felspar, compacted to a state as 

 hard as the granite which I have already described as of the 

 same composition. A coarser conglomerate consists of small 

 fragments of granite, or of quartz and felspar, cemented by argil- 

 laceous schist. Other varieties contain fragments of argillace- 

 ous schist, or various fragments united by sand ; and some are 

 purely formed of fragments of schist with an argillaceous 

 cement. I must however observe, that the proportion of these 

 conglomerates to the finer sandstones at this place, is very 

 considerable. 



Such is the mineralogical description of the several rocks at 

 this place, as far as it seems necessary to notice them for the 

 objects in view. But I must not conclude it without remark- 

 ing, that there are many more varieties of conglomerate pre- 

 sent in some part or other of this junction ; which, by reason 

 of the altitude and precipitous nature of the cliffs, are inacces- 

 sible in their native places. This is a necessary conclusion 

 from the quantity and variety of the fragments found on the 

 beach, which present all those resemblances to some of the 

 specimens of the granite already noticed. 



From these facts, two questions in the first instance arise, 

 namely, whether they are sufficient to prove that the granite is 

 stratified, and whether the apparent gradation between it and 

 the conglomerate, which it so much resembles, is real. Cir- 

 cumstances so important in geological science must not be 

 passed over slightly or decided on hastily ; since resemblance, 

 in many other cases than this, does not constitute identity. 



That the great mass of the granite is not stratified, appears 

 from its solid continuity downwards, and from the peculiar 

 fracture and structure which I have already described. The 

 appearances at the junction are too limited to justify any con- 

 clusion, even with respect to the immediate surface ; and they 

 are at best but equivocal. An analogy may set this difficulty 



