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| Keywords: The Quarterly journal of the Geological Society of London (12712067234).jpg 12 <br> GEOLOGICAL MEMOIRS <br> J- o <br> « o <br> – £ <br> Ci 5S <br> -' t- <br> U u to <br> Beyond the lines b b b b the orthoklase is less developed be- <br> comes mixed with about as much oligoklase and quartz and then <br> forms a graphic granite which at other parts by the addition of <br> mica in small plates puts on the appearance of ordinary granite <br> Orthite Zircon Malakon Oerstadite Apatite Yttrotitanite <br> Magnetite c M ere found here <br> The finest representation <br> given of the structure of such <br> granitic masses is shown in <br> the vertical section of the <br> felspar quarry at Helle near <br> N9eskilen fig 5 The scale <br> may be judged of from the <br> section itself which at the <br> highest point is about 1 5 feet <br> The felspar is here quarried <br> for technical purposes <br> On the surface is seen a <br> covering of gneiss not more <br> than from 1 to 2 feet thick <br> showing a regular and nearly <br> perpendicular foliation ; be- <br> low this we have on the one <br> hand a orthoklase graphic <br> granite and on the other <br> b oligoklase graphic gra- <br> nite <br> Still lower the constituent <br> minerals of the granite viz <br> quartz ' orthoklase o <br> and mica x are developed <br> on an immense scale ; the <br> mica even being in plates <br> of enormous size and of <br> many square yards area <br> The masses of quartz and <br> orthoklase here found some- <br> times show traces of cry- <br> stalline faces <br> Underneath the whole we <br> have graphic granite m <br> going over to ordinary gra- <br> nite of a fine grain <br> Several minerals occur <br> here and amongst others may be mentioned two new minerals calle d <br> Alvite and Bragite as well as Orthite in crystals and masses up to <br> the size of 14 to 15 lbs <br> From the observations made in various parts of this district it <br> would appear that the mica present in such granite has a very de- <br> terminate relation to the occurrence of extraneous minerals which <br> lO <br> 2 <br> o <br> o <br> so <br> o <br> y a <br> u-g CS 35615220 110213 51125 Page 12 Text v 11 http //www biodiversitylibrary org/page/35615220 1855 Geological Society of London Biodiversity Heritage Library The Quarterly journal of the Geological Society of London v 11 1855 Geology Periodicals Smithsonian Libraries bhl page 35615220 dc identifier http //biodiversitylibrary org/page/35615220 smithsonian libraries Information field Flickr posted date ISOdate 2014-02-23 Check categories 2015 August 26 CC-BY-2 0 BioDivLibrary https //flickr com/photos/61021753 N02/12712067234 2015-08-26 19 58 06 cc-by-2 0 PD-old-70-1923 The Quarterly journal of the Geological Society of London 1855 Photos uploaded from Flickr by Fæ using a script | ||||
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