398 C. CALLAWAY ON THE NEWEK GNEISSIC 



and gritty characters always to be observed at the base. Some of 

 it is brecciated by crushing. 



Turning to the west, we descend the slope to the Loch. The dip 

 of the quartzite becomes less and less steep, till, in the shore, it is 

 about 15°, and is of the Annelidian type. This dip is continued to 

 the north along the beach to nearly opposite Heilem ferry. Here the 

 Dolomite occurs at a short distance to the west, but no junction is 

 visible. 



Without leaving the hare rock, we have thus traced the quartzite 

 from the horizontal right over to almost the horizontal in inverted 

 position. No clearer evidence of overthrow can be desired. Yet 

 this is the " Upper " Quartzite of all authors except Nicol ! 



Ground between Druim-an-tenigh and the sections on Camas-an- 

 Duin. — The overthrown quartzite at the south end of Druim-an- 

 tenigh can be traced continuously across the opening of the Arnaboll 

 valley to the remarkable sections next to be described. The rock (An- 

 nelidian) is very well seen overhanging the road, dipping E.S.E. at 

 50°. As these outcrops are so conspicuous, and the beds appear so 

 clearly to pass under the gneiss close at hand to the east, a hasty 

 inspection would naturally lead to the Murchisonian conclusion. 

 Nicol, however, held that the beds were reversed, grounding his 

 opinion on the fact that " the openings of the Annelid- tubes and the 

 ripple-marks, which are regularly found on the upper surfaces of 

 the beds, are here on the lower faces." But as the marks on the lower 

 surface of a bed are a facsimile of those on the upper surface of the 

 bed in contact, it is not surprising that this evidence has not been 

 held to be convincing. I have studied the rock with this test in 

 view ; but I could never find it to be of any service, the upper face 

 of a bed presenting the marks sometimes in relief, sometimes in 

 depressions. 



Sections (three) on Oamas-an-Duin (fig. 8). — These sections 

 are even more satisfactory than that described at Druim-an-tenigh, 

 since they display the Assynt series complete in all its mem- 

 bers *, and the overthrown eastern limb of the fold is brought into 

 direct relation with the undisturbed western side. 



The southern margin of the Bay of Camas-an-Duin runs E. and 

 W. ; and the rocks are clearly exposed along the whole distance (1) 

 at the shore-level, (2) along the road, (3) along the ridge to 

 the south. 



Commencing the shore-section at the little bay east of the Pictish 

 Tower, we first identify the Annelidian Quartzite, and, by climbing 

 up to the road, connect it with the overthrown quartzite just de- 

 scribed. The dip, which at the road is 50°, rises towards the shore ; 

 and at about high-water mark it has become vertical. Then the 

 beds begin to dip to W.N.W., the angle falling gradually to 60°. 

 Here the strike curves round, so that the dip changes to W. and 

 W.S.W., the strike corresponding with the last dip being maintained 

 through the section. The dips now fall to 30°-20°. At the little 



* Except, of course, the Torridon, which does not occur east of Durness. 



