A Summary of Progress in Petrography. in 1887-1896 |
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Page 8
... eruptive rocks of Ariège , and the second is on the acid inclusions in the volcanic rocks of the Auvergne . In the former the marbles of Mercus and Arignac are carefully described . In them occur two varieties of humite , brucite ...
... eruptive rocks of Ariège , and the second is on the acid inclusions in the volcanic rocks of the Auvergne . In the former the marbles of Mercus and Arignac are carefully described . In them occur two varieties of humite , brucite ...
Page 14
William Shirley Bayley. In sketch of the geology of the Japanese Islands Harada ' gives short descrip- tions of Archean gneisses and schists , and of eruptive rocks of more recent age . Among the schists are mentioned graphitic sericite ...
William Shirley Bayley. In sketch of the geology of the Japanese Islands Harada ' gives short descrip- tions of Archean gneisses and schists , and of eruptive rocks of more recent age . Among the schists are mentioned graphitic sericite ...
Page 23
... eruptive . As in the case of the diorite contact belt , there have also been ... rocks have become aggregates of cordierite , anda- lusite , plagioclase ... rocks is colorless and non - pleochroic , but it becomes brown and ...
... eruptive . As in the case of the diorite contact belt , there have also been ... rocks have become aggregates of cordierite , anda- lusite , plagioclase ... rocks is colorless and non - pleochroic , but it becomes brown and ...
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... rocks Lang2 proposes to regard as a rock individual the product of a ... eruptive group , that is a rock individual which has been forced from the ... rocks from the point of view of its author are not immediately perceptible ...
... rocks Lang2 proposes to regard as a rock individual the product of a ... eruptive group , that is a rock individual which has been forced from the ... rocks from the point of view of its author are not immediately perceptible ...
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... rocks Lang ' proposes to regard as a rock individual the product of a ... eruptive group , that is a rock individual which has been forced from the ... rocks from the point of view of its author are not immediately perceptible ...
... rocks Lang ' proposes to regard as a rock individual the product of a ... eruptive group , that is a rock individual which has been forced from the ... rocks from the point of view of its author are not immediately perceptible ...
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Common terms and phrases
acid Al,O alteration Amer AMERICAN NATURALIST analysis andalusite angle aragonite augite axial ratio basalts beryl biotite brucite Bull calcite calcium chlorite cleavage Colby University color colorless composition constituents containing cordierite corresponding crystalline crystals density described diabase double refraction dyke eruptive rocks Fe,O Fe₂O feldspar FeO MgO CaO FeO MnO forms formula Franc gabbro-diorites gabbros garnet Genth gneisses granite granulites ground-mass H₂O habit hexagonal hornblende humite hypersthene imbedded inclusions Jour Kryst leucite masses melanophlogite metacinnabarite mica mineral MINERALOGY AND PETROGRAPHY.¹ Mitth molecules muscovite Neues Jahrb nosean occur olivine optical original orthoclase ottrelite parallel Penfield Petrog PETROGRAPHY.¹ Petrographical phenacite plagioclase plane plates polymorphism prismatic produced pseudomorphs pyroxene quartz regarded rock individual Rosenbusch schistose schists serpentine silica sodium soluble specific gravity specimens spinel structure substance sulphur symmetry tabular temperature tonalite tourmaline twinned varieties W. S. Bayley Waterville yielded Zeits zircon zone
Popular passages
Page 19 - The plane of the optical axes is perpendicular to the plane of symmetry, and makes with c an angle of °7 in acute /9. A = b. 2H na = 104° 27'.
Page 14 - The larger part of the dust is thought to be a sediment from the air, and to have been obtained by it from a region of crystalline schists. The chondri, on the other hand, are thought to be of cosmic origin, since they are similar to the chondri obtained in deep-sea soundings. If the amount of the dust collected from the snow in Greenland represents the fall of one year, the total amount falling upon the entire surface of the earth in this time is 125 million kilograms, equivalent to a cube of thirty-one...
Page 14 - Wiilfing 21 for investigation, by whom it has been found to consist in greater part of feldspar, quartz, mica, and hornblende. There are present in it also garnet, zircon, magnetite, augite, and sillimanite, and with them is mixed a nitrogenous organic substance. The most interesting constituents of the dust...