MAKE A MEME
View Large Image
| View Original: | The_Quarterly_journal_of_the_Geological_Society_of_London_(13936963171).jpg (2096x1182) | |||
| Download: | Original | Medium | Small | Thumb |
| Courtesy of: | commons.wikimedia.org | More Like This | ||
| Keywords: The Quarterly journal of the Geological Society of London (13936963171).jpg 82 PROF T G BONNET ON TWO TEAVEESES OE TEE <br> base of the hill crowned by the celebrated forts is a felspar-acti- <br> nolite rock possibly of igneous origin followed by mica-schist <br> and a dull green rock banded with epidote dipping much as before <br> The rock in this neighbourhood is stronger and less easily weathered <br> than that higher up the valley and recalled to my mind some of <br> Fig 4 ” Diagram of ' stratification-foliation in Calc-mica-schist <br> near Col cle Sestrie r res <br> The lines roughly indicate micaceous layers ; the long arrow is parallel with <br> the cleavage-foliation of the mass ; the small arrow shows the place <br> where a specimen was taken for examination p 103 <br> the chloritic and micaceous rocks about Zermatt or near St Vincent <br> in the Yal d'Aoste f Below Fenestrelle this change in character <br> becomes yet more marked The rocks now are more massive form- <br> ing bolder crags which are no longer masked by a talus of shivery <br> schist ; in short the same change in the scenery may be observed <br> Consists chiefly of epidote actinolitic hornblende quartz felspar and hsema- <br> tite with some sphene and rutile The microscopic structure is interesting in <br> many ways but it is enough for my present purpose to say that subsequent <br> mineral rearrangement has made it difficult to be sure of the original condition <br> of the rock but I think that it probably was igneous and that pressure has not <br> been the sole agent of change <br> t Minerals quartz epidote mica white and brown chlorite probably in <br> part at least replacing the latter garnet red a little rutile and a colourless <br> doubly refracting mineral of ill-defined limit and form probably allied to zoisite <br> or epidote The rock is distinctly foliated and banded The constituents <br> especially the white mica are fair-sized and well defined as if freely formed ; so <br> if the foliation results from pressure a good deal of mineral change has <br> subsequently occurred The structure is for a schist a little abnormal ; possibly <br> that may be connected with the presence of a neighbouring intrusive mass 36939863 113696 51125 Page 80 Text 45 http //www biodiversitylibrary org/page/36939863 1889 Geological Society of London Biodiversity Heritage Library The Quarterly journal of the Geological Society of London v 45 1889 Geology Periodicals Smithsonian Libraries bhl page 36939863 dc identifier http //biodiversitylibrary org/page/36939863 smithsonian libraries Information field Flickr posted date ISOdate 2014-04-21 Check categories 2015 August 26 CC-BY-2 0 BioDivLibrary https //flickr com/photos/61021753 N02/13936963171 2015-08-26 06 54 47 cc-by-2 0 PD-old-70-1923 The Quarterly journal of the Geological Society of London 1889 Photos uploaded from Flickr by Fæ using a script | ||||
.jpg){kind=link}
