A Summary of Progress in Petrography. in 1887-1896 |
From inside the book
Results 1-5 of 14
Page 8
... gneisses of Norway . The pyroxene and amphibole gneisses of this region and the wernerite gneisses present few peculiarities . The marbles , pyroxene gneisses , and granu- lites of St. Barthélemy are all marked by interesting features ...
... gneisses of Norway . The pyroxene and amphibole gneisses of this region and the wernerite gneisses present few peculiarities . The marbles , pyroxene gneisses , and granu- lites of St. Barthélemy are all marked by interesting features ...
Page 9
... gneisses rich in quartz , and frequently containing cordierite , sillimanite , garnet , corundum , diaspore , and zircon . The changes effected in them by the basic lavas varies in intensity , but not materially in kind . In extreme ...
... gneisses rich in quartz , and frequently containing cordierite , sillimanite , garnet , corundum , diaspore , and zircon . The changes effected in them by the basic lavas varies in intensity , but not materially in kind . In extreme ...
Page 10
... gneissic aspect , thought by Herrimann and Weber to be the result of flowage.- -The micro structure of several calcareous oölites from Iowa , and of siliceous oölites from Pennsylvania , is represented by Messrs . Barbour and Torrey as ...
... gneissic aspect , thought by Herrimann and Weber to be the result of flowage.- -The micro structure of several calcareous oölites from Iowa , and of siliceous oölites from Pennsylvania , is represented by Messrs . Barbour and Torrey as ...
Page 14
... gneisses and mica - schists of the Mont Blanc " massif is thought not to be an original contact , but one brought about by dislocations . The conclusions of Lévy and Graeff are thus seen to be in accord in some particulars , while in ...
... gneisses and mica - schists of the Mont Blanc " massif is thought not to be an original contact , but one brought about by dislocations . The conclusions of Lévy and Graeff are thus seen to be in accord in some particulars , while in ...
Page 14
... gneisses and schists , and of eruptive rocks of more recent age . Among the schists are mentioned graphitic sericite ... gneiss garnets are produced , in amphibolites andalusite is a new product , and in limestone wollastonite and ...
... gneisses and schists , and of eruptive rocks of more recent age . Among the schists are mentioned graphitic sericite ... gneiss garnets are produced , in amphibolites andalusite is a new product , and in limestone wollastonite and ...
Other editions - View all
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...