364 



PKOCEEDINGS OP THE GEOLOGICAL SOCIETY. 



[Dec. 1, 





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which on the west rise from the cove of Clash- 

 carnach to the summit of Skrishven (1213 feet 

 above the sea), on the eastern flank of which 

 they are unconformably overlapped by the 

 lowest beds of the quartz-rock (c^), which dip 

 away to the E.S.E. and form the base of the 

 Lower Silurian rocks of Durness, as shown in 

 the Section, fig. 3. 



In the interior of the tract called the*' Parph," 

 or the mountainous district lying between 

 Durness on the N.E. and Loch Laxford on the 

 S.W., these Old purple sandstones are largely 

 developed, also capping the fundamental grey 

 gneiss. They are indeed well exhibited near 

 the summit-level of the high road to Scourie, 

 or at the Grwalin Inn, whence they are seen 

 to pass under the great quartzose Silurian 

 series on the east. They extend, however, 

 very little further to the east, since the gneiss 

 rising in the western flanks of Foinaven and 

 Ben Stack is at once covered by the lower 

 quartz-rock. The Cambrian sandstone is again 

 magnificently displayed in the western cliflfe 

 of the Island of Handa, where it constitutes 

 cliffs upwards of 500 feet high, much fre- 

 quented by sea-fowl, and where the strata, 

 slightly deviating from horizontahty, are also 

 laid open by fine vertical fissures; the dip 

 inclining, on the whole, a few degrees to 

 the S.E. Again, in the promontory of Rhu 

 Storr, or the Point of Assynt, and all along 

 the shores of Lochs Inver and Enard, the 

 fundamental gneiss is unconformably super- 

 posed at a little distance inland by masses 

 of the Cambrian Red Sandstone, which, to 

 the south of the Kyles of Strome, rise into 

 the lofty peaks forming the chief beauty of 

 the tract of Assynt and constituting from 

 north to south the detached mountains of 

 Queenaig, Suilven, and Canisp, each separated 

 by lower tracts of fundamental gneiss, as in 

 the preceding woodcut, fig. 2, and thence ex- 

 tending into similar ranges in Ross-shire. On 

 this occasion I explored carefuUy (the weather 

 favouring) the eastern flanks of Suilven, where 

 the nearly horizontal strata of that noble 

 mountain are seen in their greatest extent to 

 repose upon the fundamental gneiss. It is 

 about halfway along the side of the mountain 

 that the whole mass has been afiected by a 

 great E. and W. fault, to which my attention 

 was first called bv Colonel James. 



