Dr. Mac Culloch on Quart% Rock. 465 



too, although not an authority in a case of this nature, describes 

 quartz about Loch Broom, and more cursory observers have given us 

 reason to think that the generality of the higher mountains of this 

 northern tract of Scotland are composed of " quartz." There is 

 little doubt that the whole of this elevated tract is of the same for- 

 mation as that under consideration, and it ought therefore perhaps 

 (according to the remarks I have already made on Jura) to be 

 ic.nked with the Transition rocks ^ if we adopt the divisions of 

 Werner. 



If this be proved it will be highly Interesting to ascertain the 

 positions of 'all the strata throughout this whole district. Of the 

 unstratified rocks it will always be difficult to determine what por- 

 tion has been removed, or what changes of the original position 

 may have taken place, as we have no guide to conduct us in our 

 judgment, ignorant as we must generally remain of their original 

 forms. With the stratified rocks the case is otherwise, their exist- 

 ing forms furnishing us with a palpable index, by which we may 

 discover either the changes of position they have suffered, or the 

 waste they have undergone. Certainly the north-west coast of 

 Scotland gives evidence of an enormous waste of the surface, and 

 opens an ample field for the speculations of those who have at- 

 tempted to assign the causes of that waste : to them I must at 

 present leave it. 



I have already, at the beginning of this paper, remarked the simi- 

 larity which the outline of the mountains of Sutherlandshire bears 

 to that of the Wicklow mountains. These, in the paper of Dr. 

 Fitton, above mentioned, are also called granular quartz. As I have 

 -neither seen the mountains themselves, nor any specimens from 

 them, I am unable to decide whether they are actually similar in 

 structure and geological character to the Scottish quartz mountains. 



Vol. II. 3 N 



