the Primarj/ Rocks and the Oolitic Series in the North of Scotland. 135 



In both instances the sandstone was perfectly unconformable to the older 

 schists, and separated from them by thick masses of conglomerate. Lastly, 

 the mountains of Applecross, the mineralog-ical character of which has already 

 been noticed, are regularly bedded, and have a constant dip from the coast 

 into the sea (about N.W.), at an angle which is inconsiderable when com- 

 pared with the average inclination of the older schistose rocks. They have 

 unquestionably the external character and the structure, and we believe also 

 the relations of secondary mountains. 



Again, the red sandstone series of the west coast, has been traced to a point 

 of junction not more than two or three miles south of Cape Wrath ; and, on 

 doubling the Cape, it appears on the north shore with the same character and 

 relations. Moreover, we have shown that these several deposits are, through 

 the intervention of other similar masses, connected with the old conglomerate 

 range of Caithness. We think it absolutely impossible to refer these several 

 deposits to distinct epochs ; and we therefore conclude, that the unconform- 

 able red sandstones and conglomerates of the north-western coast, are not 

 older than the lower portion of the secondary formations of Caithness and the 

 Murray Firth, and that they must be classed with the older secondary deposits 

 of England. 



In making this statement, we by no means intend to assert that there is no 

 such thing on the north-west coasts of Scotland as a primary red sand- 

 stone. We agree with Dr. MacCulloch in thinking that many of the masses 

 of quartz rock which alternate with formations universally regarded as 

 primary, are of mechanical origin. These rocks occasionally become of a 

 red colour ; and we know from experience, that it is not always possible, even 

 on the spot, to distinguish them from true secondary red sandstones. One of 

 the most striking examples of this kind may be seen immediately behind the 

 village of Ullapool. There are, therefore, great, and perhaps in some instances 

 insurmountable, difficulties (for example, in the Isle of Skye) in the way of 

 classifying the old red sandstones of the Highlands. But, fortunately, it is no 

 part of our present object to undertake their solution ; nor do they appear in 

 any way to affect the general truth of the conclusions at which we have at- 

 tempted to arrive. 



The difficulty of drawing a precise line between the primary and secondary 

 rocks of Scotland, would be greatly increased, if organic remains could be 

 found (as has been stated by Dr. MacCulloch) in any part of the older series 

 which has hitherto been regarded as primary. On the eastern shores of Loch 

 Eribol, and at the very spot indicated by the author above mentioned, we 

 found boulders of quartz rock containing conical impressions, which he sup-' 



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