Class-book of GeologyMacmillan and Company, 1886 - 516 páginas |
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Página xiv
... quartz - crystals ( Rock - crystal ) 142 142 143 145 157 45. Calcite ( Iceland spar ) showing its characteristic rhombohedral cleavage 166 46. Cube , octahedron , dodecahedron 167 47. Tetragonal prism and pyramid 167 48. Orthorhombic ...
... quartz - crystals ( Rock - crystal ) 142 142 143 145 157 45. Calcite ( Iceland spar ) showing its characteristic rhombohedral cleavage 166 46. Cube , octahedron , dodecahedron 167 47. Tetragonal prism and pyramid 167 48. Orthorhombic ...
Página xv
... quartz , and mica , from a cavity in the Mourne Mountain granite 78. Columnar basalts of the Isle of Staffa , resting upon tuff ( to the right is Fingal's Cave ) PAGE 194 197 198 206 210 216 219 79. Section of stratified rocks . 227 80 ...
... quartz , and mica , from a cavity in the Mourne Mountain granite 78. Columnar basalts of the Isle of Staffa , resting upon tuff ( to the right is Fingal's Cave ) PAGE 194 197 198 206 210 216 219 79. Section of stratified rocks . 227 80 ...
Página 21
... quartz veins that traverse the solid granite can be recognised running through the decayed and fresh parts alike . But besides being broken into pieces , the granite rots away and loses its cohesion . Some of the smaller pieces can be ...
... quartz veins that traverse the solid granite can be recognised running through the decayed and fresh parts alike . But besides being broken into pieces , the granite rots away and loses its cohesion . Some of the smaller pieces can be ...
Página 157
... Quartz - crystals ( Rock - crystal ) . the majority of rocks . It occurs abundantly as the mineral quartz , the colourless transparent forms of which are known as rock - crystal ( Fig . 44 ) , and also in combination with various ...
... Quartz - crystals ( Rock - crystal ) . the majority of rocks . It occurs abundantly as the mineral quartz , the colourless transparent forms of which are known as rock - crystal ( Fig . 44 ) , and also in combination with various ...
Página 165
... quartz , and in irregular pieces or nuggets dispersed through the gravel deposits of regions where gold - bearing quartz - veins traverse the solid rocks . Omitting , however , the minerals formed of a single element , we may pass on to ...
... quartz , and in irregular pieces or nuggets dispersed through the gravel deposits of regions where gold - bearing quartz - veins traverse the solid rocks . Omitting , however , the minerals formed of a single element , we may pass on to ...
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Términos y frases comunes
abundant accumulated acid augite basin beds bones bottom Brachiopods calcareous calcite carbonate of lime Carboniferous chapter characteristic chiefly clay containing corals Cretaceous crinoids crystalline crystals cycads decay deposits detritus Devonian earth earth's crust Eocene Europe evidence example extinct fauna feet thick fishes fissures fossils genera geological history geologist glacier globe gradually granite gravel ground iron Jurassic kinds known lakes land lava layers limestone living lower marine marked marls masses materials Mesozoic miles mineral matter Miocene molten mountains natural North occur Old Red Sandstone organic remains original Paleozoic period Permian plants and animals Pliocene present preserved probably quartz rain records regions rivers salt sand schists sea-floor sediment sedimentary rocks shales sheets shells siliceous Silurian slopes soil solid sometimes species stone strata stratified stream structure substance surface terrestrial Tertiary tion trace Triassic upper valley various vegetation veins vent volcanic