The American Journal of ScienceJ.D. & E.S. Dana, 1909 - Earth sciences |
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Common terms and phrases
amount anal area angle Archelon Archelon ischyros B-MgSiO basalts birefringence branched calcium carapace cell cent MgSiO character chemical cm³ composition containing copper cross veins crucible crystals cubitus curve deposits described determined diameter diopside dioxide drift elements erosion eruption etch figures eutectic filtration Foerstner forked fossil front wing genera genus Geological Survey Graham Island grams heat hind wing indicated insects inversion point ischyros Journal lead dioxide Length of front limestone liquid magnesium silicate material measurements melting method microscope mineral mix-crystals mixtures Museum nitric acid observed obtained optical original oxalate oxalic acid oxide Pantelleria paper pegmatite Permian plastron plates portion potassium potassium chromate precipitate present Protostega pseudo-wollastonite quartz radial sector radio-active radius region rocks shales shown sodium sodium carbonate solid solution species specimen subcosta surface Table temperature Text figure thorium tion valley volume width wollastonite
Popular passages
Page 293 - Lawrence on the other, swept around the Adirondacks and entered the Mohawk valley at either extremity, while a feebler current, at the height of glaciation, probably passed over the Adirondacks and gave to the whole a southerly trend.
Page 448 - ... never reached that temperature. These criteria were in large part indicated by O. Miigge and have been applied here to a number of natural quartzes occurring in different kinds of rocks, the net result of the investigation being that vein and geode quartzes and certain large pegmatite quartz-masses and pegmatite veins were formed below 575°, while graphic and granite pegmatites and granites and porphyry quartzes were in all probability formed above 575°.
Page 299 - ... taken place and valleys and basins are formed whose width depends upon the angle of dip and the softness of the strata which have been scooped out. The strata are presented in the most favorable attitude for abrasion. The wearing down would go on till the resisting rock front had attained a hight and weight sufficient to counterbalance those of the glacier." In the Black river valley the ice moved from the crystallines against the slightly upturned edges of the sediments. In much the same way...
Page 345 - Under certain conditions of crystallization iiepheline-albite rock might form, while, under conditions of high pressure during consolidation or after, jadeite, which has a much lower molecular volume, would be produced, the residual molecule forming albite or nepheline according to which molecule was in excess in the original magma. In the neighborhood of Tawmaw occur various crystalline schists which are intruded into by granite.
Page 448 - Miigge, who finds the high temperature phase, /8-quartz, to be in all probability hexagonal and trapezohedral-hemihedral, while the low-temperature a-quartz is hexagonal and trapezohedral-tetartohedral. This particular relation between the two phases entails certain consequences which can be used as criteria to distinguish quartz which has been heated above 575° from quartz which has never reached that temperature. These criteria were in large part indicated by O. Miigge and have been applied here...
Page 268 - Casiquiari, Pacimoni, Huallaga, and Pastasa: as also to the cataracts of the Orinoco, along the eastern side of the Andes of Peru and Ecuador, and the shores of ,the Pacific, during the years 1849-1864, by Richard Spruce, Ph.
Page 196 - Congress in the United States National Museum, the Bureau of American Ethnology, the International Exchanges, the National Zoological Park, and the Astrophysical Observatory.
Page 88 - Mine Sampling and Chemical Analyses of Coals Tested at the United States Fuel-Testing Plant, Norfolk. Va.. In 1907. By John Shober Burrows.
Page 196 - SMITHSONIAN INSTITUTION. Annual Report of the Board of Regents for the Year Ending June 30, 1937.
Page 175 - ... points which seem to have the most importance as bearing on the correlation of the Wellington are the following: (1) The complete absence of species in any way confined to or distinctive of the Coal Measures. (2) The comparatively small number of species originating as early as Upper Coal Measures time. (3) The presence of a few species common to and characteristic of the Permian of Europe. (4) The close relation of the new forms to species characteristic of the European Permian. (5) The distinctly...