A Summary of Progress in Petrography. in 1887-1896 |
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Page 1886
... gabbros , and sometimes they are original . In every case it is found that there is a tendency of the rock to possess as constituents one or more rare rock - forming minerals . As the writer has examined all these very carefully , his ...
... gabbros , and sometimes they are original . In every case it is found that there is a tendency of the rock to possess as constituents one or more rare rock - forming minerals . As the writer has examined all these very carefully , his ...
Page 1894
... gabbros , and sometimes they are original . In every case it is found that there is a tendency of the rock to possess as constituents one or more rare rock - forming minerals . As the writer has examined all these very carefully , his ...
... gabbros , and sometimes they are original . In every case it is found that there is a tendency of the rock to possess as constituents one or more rare rock - forming minerals . As the writer has examined all these very carefully , his ...
Page 1
... gabbro at Carrock Fell in the Lake District , England . It consists of a green glass en- closing spherules of quartz , feldspar , and granular aggregates of augite , and porphyritic crystals of the same minerals . - Prof . Bonney10 has ...
... gabbro at Carrock Fell in the Lake District , England . It consists of a green glass en- closing spherules of quartz , feldspar , and granular aggregates of augite , and porphyritic crystals of the same minerals . - Prof . Bonney10 has ...
Page 4
... gabbros , green- stones , granulites , and hornblende - schists of the Lizard , Eng . , as parts of the same rock - mass , the latter - named rocks , according to him , having originated from the former by pressure.- -Mr . Marstens 7 ...
... gabbros , green- stones , granulites , and hornblende - schists of the Lizard , Eng . , as parts of the same rock - mass , the latter - named rocks , according to him , having originated from the former by pressure.- -Mr . Marstens 7 ...
Page 11
... gabbros are likewise derived from clastic materials will not find such ready acceptance , as there seems to be no positive evidence that such rocks were originally sediments , rather than eruptives , which squeezed themselves into ...
... gabbros are likewise derived from clastic materials will not find such ready acceptance , as there seems to be no positive evidence that such rocks were originally sediments , rather than eruptives , which squeezed themselves into ...
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Common terms and phrases
acute bisectrix Al,O Amer AMERICAN NATURALIST amphibole analysis andesites apatite augite axial ratio basalt biotite bisectrix brown Bull calcite Colby University color colorless composition containing cordierite corresponding described diabase diorites double refraction dykes Edited by Dr epidote eruptive Fe,O feldspar FeO CaO MgO FeO MnO Förh formula gabbro garnet Geol gneiss grains granite green ground-mass H₂O hardness hexagonal hornblende inclusions isomorphous Jour Kryst Lacroix lamellæ lithophysæ lustre magma magnetite MAKERS SYRACUSE manganese mica microlites mineral occurs MINERALOGY AND PETROGRAPHY.¹ molecule monoclinic Na,O Na₂O nepheline Neues Jahrb olivine optical angle optical axes original orthoclase orthorhombic Petrog PETROGRAPHY.¹ Petrographical phenocrysts plagioclase pleochroic porphyritic porphyritic crystals pressure prismatic produced pyroxene quartz regarded resembles rhombohedral rocks scapolite schists silica small crystals specific gravity spherulites structure substance symmetry thin section tion twinning plane variety W. S. Bayley Waterville yellow yielded Zeits
Popular passages
Page 5 - The olivine is surrounded by a reactionary rim consisting of an inner zone of hypersthene and an outer one of actinolite.