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| Keywords: The Quarterly journal of the Geological Society of London (12960440064).jpg VICI2« ITT OF T£LE UPPER PAET OF LOCH MAEEE 97 <br> Maree as far as Ben Slioch and a little to the north of the Loch- <br> Maree hotel They vary considerahly some as in the Laggau <br> valley being mainly quartz and felspar with a little of a green <br> micaceous mineral others ordinary mica- or hornblende-gneiss <br> others again rather hornblendic or chloritic schists All how- <br> ever exhibit conspicuously that massive structure which early <br> observers rightly fixed upon as characteristic and as a rule <br> are fairly uniform for a considerable vertical thickness The <br> microscope shows that quartz and felspar are always present exhi- <br> biting the rather irregular granular form characteristic of gneissic as <br> opposed to granitic rocks fig 4 The quartz is generally fairly clear <br> Fig 4 ” Hebridean Gneiss from near base of Ben Slioch <br> enclosures or cavities being verj minute though in one or two cases <br> there is a considerable amount of dusty opacite The felspar usually <br> more or less decomposed varies in quantity rather predominating in <br> the specimens from near the junction in Glen Laggan These appear <br> to contain microcline ; it is perhaps present in the others with con- <br> siderable quantities of plagioclase probably oligoclase as well as <br> orthoclase Epidote microliths and other decomposition products are <br> present largely in some specimens One of those from Glen Laggan <br> consists almost wholly of quartz and felspar with a minute quantity of <br> a pale hornblendic mineral and a Kttle opacite and magnetite <br> being almost exactly like specimens from North Wales and Shropshire <br> for which I have proposed the name granitoidite Another more <br> gneissic contains a chloritic mineral and a little pale-coloured mica <br> A third macroscopically much greener than the others appears to <br> owe its colour chiefly to quantities of very minute epidote <br> Mica is conspicuously present in two specimens collected by the road- <br> side north of Loch-Maree hotel in one from the floor of Glen Laggan <br> some distance up stream above the gorge and in one collected by <br> the shore of Loch Maree at the south end of the base of Ben Slioch <br> The third group and most of the second are universally admitted to be <br> the Hebridean gneiss <br> Q J G S No 141 H 36090432 111264 51125 Page 97 Text 36 http //www biodiversitylibrary org/page/36090432 1880 Geological Society of London Biodiversity Heritage Library The Quarterly journal of the Geological Society of London v 36 1880 Geology Periodicals Smithsonian Libraries bhl page 36090432 dc identifier http //biodiversitylibrary org/page/36090432 smithsonian libraries Information field Flickr posted date ISOdate 2014-03-06 Check categories 2015 August 26 CC-BY-2 0 BioDivLibrary https //flickr com/photos/61021753 N02/12960440064 2015-08-26 16 57 05 cc-by-2 0 PD-old-70-1923 The Quarterly journal of the Geological Society of London 1880 Photos uploaded from Flickr by Fæ using a script | ||||
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