ROCKS OP THE NORTHEEN HIGHLANDS. 



391 



red felspar bits of -the lowest zone. The 

 pressure to which the rock has been sub- 

 jected has flattened the quartz grains ; and 

 the cleavage and alteration are similar to 

 those of the Annelidian Quartzite above. 

 These beds actually lie to the east of the 

 junction, so that on the strike they pass 

 under the almost horizontal gneiss. East 

 of this point the Hebridean rises up and 

 meets the newer gneiss. It is therefore 

 evident that this mass of quartzite is a 

 syncline sharply folded back upon itself, 

 and closely squeezed in the angle between 

 the older and younger gneiss. 



The curved beds of quartzite on the slope 

 present a curious phenomenon. The joints 

 are almost at right angles with the bed- 

 ding, and are open much wider than the 

 planes between the beds ; so that at a dis- 

 tance the quartzite appears nearly hori- 

 zontal, and the seeming beds are contorted. 

 This twofold disturbance, the folding-back 

 of the true beds and the contortion of the 

 slabs between the joints, points to excessive 

 lateral pressure acting from the east. 



I have said that the Hebridean rises 

 towards the east, so as to meet the Cale- 

 donian. This is more clearly seen by de- 

 scending to the level of the stream. A little 

 below the reversed fold just described, 

 and a few feet above the stream, is a 

 band of conglomerate about 4 inches thick. 

 The pebbles, which are of quartz in a ma- 

 trix of small bits of quartz and felspar, 

 are flattened as if by pressure. This seam 

 is un distinguishable from a thin band 

 which forms the base of the quartzite on 

 Loch Emboli. It dips to the N.W. at 20°, 

 and it rests immediately upon grey Hebri- 

 dean gneiss, to the surface of which it is 

 plastered. The gneiss has its normal strike 

 to the N."W. The dip of this conglomerate 

 shows us that the surface of the gneiss 

 slopes up towards the east, and it confirms 

 the previous evidence as to the reversed 

 dip of the quartzite. Following up the 

 junction, we soon lose the conglomerate un- 

 der bog ; but the Hebridean can be traced 

 up the slope at about the same angle, gra- 

 dually rising to the east of the quartzite to 

 meet the overhanging Caledonian. 



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