30 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [NoV. 19, 



relations established at Gairloch and further north demand that we 

 should regard the valley as a line of fault, bringing down the lime- 

 stone beds to a lower level than the sandstones on which they were 

 deposited. The sandstone, too, seems to have been thinning out 

 here to the east, as the lofty mountains in the interior, seen both 

 from Loch Keeshorn and on the road from Loch Carron to Auch na 

 Sheen, appear to be capped only by the quartzite, covered in some 

 places by darker beds, but without the red sandstone below. 



The section from Kyle Aken Ferry to Balmacarra, and thence to 

 the mountains of Kintail, appears to confirm these general relations. 

 The red sandstone which occurs near the Kyle dips east under a 

 peculiar group of slaty rocks, the representatives, according to Mac- 

 culloch, of the quartzite series. It consists of blue or grey clay-slates 

 and coarse grits, made up of quartz, felspar, and fine scales of mica, 

 the whole in many respects not unlike some portions of the Silurian 

 strata in the South of Scotland. The stratification is very well 

 marked, and the beds are also intersected by distinct planes of 

 cleavage — one set parallel to the bedding, others oblique at various 

 angles. This group of rocks dipping E.S.E. continues to beyond 

 the inn, but before reaching Loch Ling several veins of red felspar- 

 porphyry interrupt the succession. Near Dornie Ferry a large 

 mass of dark-green dioritic serpentine forms some low hills or knolls. 

 Near Totaig, on the south side of Loch Duich, an irregular broken 

 and fissured bed of white crystalline limestone, mixed with actyno- 

 lite, pyrite, and other minerals, occurs in connexion with a similar 

 igneous rock or a syenite. Other larger masses of limestone crop 

 out on the north-east shore of Loch Duich, probably in two or more 

 courses, and dip at a high angle (50°) to the south-east. These 

 limestones are connected with the true metamorphic rocks of the 

 country ; but it is impossible to avoid remarking that their prox- 

 imity to the quartz series, and the great rarity of limestone in the 

 gneiss of the north-west of Scotland, give some probability to the 

 view that they may be only a more highly altered portion of the 

 quartzite dipping under the great mountain group of the Bealloch 

 of Kintail *. 



Skye. — x\t this point, the great bands of red sandstone and quartz- 

 ite terminate on the mainland, but, according to Dr. Macculloch, are 

 continued through the district of Sleat in the south of Skye. This 

 observer describes the relations of the rocks in that tract as exceed- 

 ingly complex, and the sections drawn in his work on the Western 

 Isles by no means lessen the difiiculty. The section (fig. 7) from 

 Isle Oransay to Broadford intersects the whole formations, from the 

 gneiss on the one hand to the newer secondary deposits on the other. 

 On the south coast at Isle Oransay, the gneiss, sometimes horn- 

 blendic, is seen dipping south-east towards the mainland. On the 

 north of it, a mass of claystone, or felspar-porphyry, occurs in a de- 

 pression partially filled up by detritus concealing the rocks. Beyond 



* It is worthy of notice also, that in these mountains granite first appears in 

 mass, on the west coast, in the whole range from Cape Wrath to the south. 



