A Summary of Progress in Petrography. in 1887-1896 |
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Page 14
... 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 ...
... 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 ...
Page 16
... crystalline masses in a vein , associated with albite , quartz , and spodumene . It is , as a rule , fresh . Occasionally it is extensively altered into hureaulite through the intermediate prod- uct dickinsonite . The succession in age ...
... crystalline masses in a vein , associated with albite , quartz , and spodumene . It is , as a rule , fresh . Occasionally it is extensively altered into hureaulite through the intermediate prod- uct dickinsonite . The succession in age ...
Page 22
... crystalline schists , in which contact alteration has been effected . The tonalite is the rock so well known as comprising a large part of the Adamello group of the Alps . It is essentially a hornblendic quartz - mica - diorite . A ...
... crystalline schists , in which contact alteration has been effected . The tonalite is the rock so well known as comprising a large part of the Adamello group of the Alps . It is essentially a hornblendic quartz - mica - diorite . A ...
Page 23
... crystalline schists found so widely spread over the country bordering on Lake Superior . The paper opens with an excellent historical review of the recent work on crystalline schists in Europe , in which all the important articles on ...
... crystalline schists found so widely spread over the country bordering on Lake Superior . The paper opens with an excellent historical review of the recent work on crystalline schists in Europe , in which all the important articles on ...
Page
... crystalline grains of mentiitätte , associated with crystals of magnes and apatite . The habit of the rare mineral is short prismate , wh pyramidal terminations P and 2P largely developed ( aval ratio = -4337 : : -5757 ) The hardness is ...
... crystalline grains of mentiitätte , associated with crystals of magnes and apatite . The habit of the rare mineral is short prismate , wh pyramidal terminations P and 2P largely developed ( aval ratio = -4337 : : -5757 ) The hardness is ...
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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...