1856.] NICOL — aUARTZITES, ETC. OF N.W. SCOTLAND. 



Fig. 7. — Section through the southern part of Sky e. 



31 



N. Broadford. 



L. Lias. 



y 1) 



a. Gneiss (lower). 

 6. Red Sandstone. 

 c. Quartzite. 



c T> z < 



X. Porphyry. 



y. Syenite. 



z. Clay-stone-porphjTy. 



this hollow, red sandstone and conglomerate beds appear, at first 

 broken and disturbed, but soon dipping regularly toW.N.W. at angles 

 ranging from 25° to 40°. The sandstoae is of a reddish-brown 

 colour, with thin yellowish layers of finer materials, but is much 

 hardened and altered, and at first sight might easily be mistaken for 

 gneiss. In many respects it closely resembles the beds above the 

 coarse breccia at the Gairloch. At the head of Loch Daal the sand- 

 stone is followed by thick beds of greyish quartzite, dipping N.W. 

 at 20°. Further north, beds resembling greywacke, with light-yellow 

 and blue slates, follow, dipping at 40° to 60° W.N.W. TRese beds 

 have the general character of the Balmacarra slates, but are softer, 

 and without cleavage. In Ben na Rhee and Ben na Capple, on the 

 east of the road, the beds appear to dip at a much higher angle, and 

 to be more quartzose in character. The next higher group of strata 

 is again red sandstone, but lighter in colour, and softer than the 

 sandstones below the quartzite. The syenite or felspar-porphyry of 

 Ben na Cham interrupts this series, but without altering the direc- 

 tion of the dip. On the north of the igneous rock, the sandstone is 

 of a whiter colour. On Broadford Bay the lias shale and limestones, 

 full of GryphcBce, Ammonites, and other characteristic fossils, appear 

 dipping 8° N. 50° W., and intersected by the most complex groups 

 of trap-veins. Beyond Broadford Bay the lias is covered by beds of 

 green-coloured columnar porphyry, both the igneous and stratified 

 rocks being again intersected by vertical veins of grey greenstone. 



This section, though the lower rocks are clearly identical, differs 

 in many important points from those formerly described. The dip 

 of the beds is now to the N.W. instead of to the S.E., as on the 

 mainland. The quartzite is no longer the white granular quartz- 

 rock of the northern sections, but in many parts rather a grey- 

 wacke or slate. The limestones do not appear in the section, but 

 the quartzite is now covered by soft red or white sandstones, and 

 these by the shales and limestones of the lias, instead of the hard 

 metamorphic gneiss of Ullapool and Loch Eriboll. The lower red 

 sandstone is evidently the same rock with that seen on the main- 

 land, and the quartzite may also be probably identified, though some- 

 what different in characters. How far the upper red and white 

 sandstones belong to this ^roup is more doubtful. 



