TICINITY OF THE TJPrEE, PART OF LOCH ITAREE. 105 



always gneissic, sometimes more, sometimes less micaceous, this 

 mineral occasionally predominating. At 750 ft. is a quartzose gneiss, 

 very like those noticed in the series in Glen Docherty, and, micro- 

 scopically, nearly related to the quartz schists at the top of that glen 

 and on the cliff above Kinlochewe. On a shoulder at 1470 ft. 

 micaceous schist (dip about 45° S.) ; at 1830 ft. garnetiferous gneiss 

 (dip almost vertical, apparently to a little S. of W.). At 1900 ft. is an 

 intrusion of garnetiferous diorite ; its felspar is much decomposed, and 

 the hornblende projects from the weathered surface like the augite in 

 the gabbro of Skye. The garnets are sometimes as large as small 

 cherries. There appear to be two bosses of it, of irregular form and 

 possibly connected. The adjoining micaceous gneiss is locally twisted 

 and disturbed. 



I continued the ascent to the edge of the corrie on the eastern face 

 of the mountain, and turned back (it being needless for my purpose 

 to proceed further) at a height of about 2480 ft. above Auchnasheen. 

 Over the upper part of the hill the dip of the gneiss is generally high. 

 Though lithologically similar to that in the lower part, it is less 

 distinctly flaggy, and the coincidence between bedding and foliation 

 is less conspicuous. After careful search I failed to find any horn- 

 blendic rock other than intrusive, and am certain that nothing 

 resembling the Hebridean series of Loch Maree could occur in the 

 comparatively short space between the spot where I stopped and the 

 summit. The strike of the rocks cannot be pressed too far as evi- 

 dence, for it is very variable. My notes include various points, from 

 nearly due jS". to nearly due W. While travelling by a slow train to 

 Dingwall, I observed that the rocks as far as Strathpeffer were 

 flaggy gneisses, generally similar to those above described — a coarser 

 variety, with large scales of white mica, occurring near the latter 

 place. 



(7) Igneous Rocks. 



There are compact greenstone dykes, as already said, in Glen 

 Laggan, cutting the Hebridean series. One of them, on the left 

 bank, a little below the gorge, I have examined ; but it has been 

 so much altered that it is difficult to give a good account of it. The 

 felspar (probably plagioclastic) has been largely replaced by minute 

 pseudomorphs. There is some dark-brown mica and pale-green 

 hornblende (probably a secondary product), and' what look like 

 diaUage or augite crystals, replaced by ferrite, opacite, viridite, and 

 earthy-looking matter. Near the head of Loch Maree (right bank) I 

 collected a massive hornblendic roek, which appears on examination 

 to be a diorite, though the structure is obscured by decomposition. 

 There are two varieties of hornblende and many small garnets. The 

 diorite of Ben Fyn consists chiefly of hornblende and red garnet ; 

 the former mineral is green and strongly dichroic, rather irregular in 

 outline, with characteristic cleavage. It contains many rather large 

 microliths, in some of which may be seen a small crystal of mag- 

 netite or some opaque mineral. Most are roundish in section, one or 

 two hexagonal, doubtless quartz. The garnet contains numerous 



