A Summary of Progress in Petrography. in 1887-1896 |
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Page 13
... constituents . Martin has examined several organic compounds , and is thereby led to the conclusion that in these the anomalies are due to strain or pressure exerted on some parts of the crystal by the more rapid growth of other parts ...
... constituents . Martin has examined several organic compounds , and is thereby led to the conclusion that in these the anomalies are due to strain or pressure exerted on some parts of the crystal by the more rapid growth of other parts ...
Page 14
... constituents of granite are mainly of the second generation , those of the first consolidation having disappeared . To the southeast of Mont Blanc are quartz - porphyries which , accord- ing to Graeff , 3 are genetically related to the ...
... constituents of granite are mainly of the second generation , those of the first consolidation having disappeared . To the southeast of Mont Blanc are quartz - porphyries which , accord- ing to Graeff , 3 are genetically related to the ...
Page 20
... constituent in carbonaceous clay slates , and in interstratified carbonif- erous eruptives . 31 Ref . Neues Jahrb . f . Min . , etc. , 1891 , I. , p . 98 . 33 Bull . Soc . Franc . d . Min . , XIII . , 1890 , p . 325 . 10 CO of alt as ...
... constituent in carbonaceous clay slates , and in interstratified carbonif- erous eruptives . 31 Ref . Neues Jahrb . f . Min . , etc. , 1891 , I. , p . 98 . 33 Bull . Soc . Franc . d . Min . , XIII . , 1890 , p . 325 . 10 CO of alt as ...
Page 22
... constituent . The schists around the tonalite belong to the older series of gneiss and mica - schists . These have been 1 Edited by Dr. W. S. Bayley , Colby University , Waterville , Me . Zeits . d . deutsch . geol . Ges . , XLII ...
... constituent . The schists around the tonalite belong to the older series of gneiss and mica - schists . These have been 1 Edited by Dr. W. S. Bayley , Colby University , Waterville , Me . Zeits . d . deutsch . geol . Ges . , XLII ...
Page 23
... constituents possess no unusual peculiarities . They are all well described , but none are analyzed . Dykes of porphy- rite cut the schists , and a single one occurs in the tonalite , but none of them merit special mention in this place ...
... constituents possess no unusual peculiarities . They are all well described , but none are analyzed . Dykes of porphy- rite cut the schists , and a single one occurs in the tonalite , but none of them merit special mention in this place ...
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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...