Mineralogy of Sky. 177 



If we proceed to the western side of this promontory for the 

 purpose of recovering these strata, we find them at Duntulm, from 

 which place they extend interruptedly for a few miles along this 

 shore, when they finally disappear. The same organic remains, 

 the same shale, the same limestone, calcareous sandstone, and sili- 

 ceous schist, mark the identity of these with the strata on the 

 eastern side, an identity still further confirmed by the prevailing 

 correspondence of their inclinations. I may at the same time add 

 that a greater facility of access to the upper beds, the only ones here 

 to be found, assists us in obtaining a more correct notion of those 

 beds which from their elevation above the shore are inaccessible on 

 the east side, and that we thus become acquainted with those nu- 

 merous varieties of the lias limestone, which having often been 

 described by geologists, serve to confirm the nature of these last and 

 uppermost of the stratified rocks of Sky. The nature and origin 

 of siliceous schistus can here also be traced in many other places 

 besides that most conspicuous one at Duntulm which I formerly 

 described ; and so many gradations between that rock and shale are 

 to be observed that the most satisfactory evidence of their connec- 

 tion can be obtained. 



From a comparison of these several facts, the details of which 

 I have from the nature of this supplementary paper thought it 

 necessary to condense, it is apparent that the fundamental rocks of 

 the district of Trotternish, are those secondary and stratified sub- 

 stances which are connected with the lias formation, and that these 

 are both surmounted and intersected by trap. If but little additio- 

 nal evidence of this view can be obtained from an examination 

 of the interior country, that little is at least satisfactory. The 

 same substances occur in numerous places, where precipitous faces 

 or the sections formed by rivers expose the rocks that lie beneath 



