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abundant AMERICAN GEOLOGIST Animike apatite Archæan augite beds Billings biotite bryozoa Cambrian character chert Cincinnati clay coal color committee Congress coral Cretaceous crystalline crystals Darwin deposits described diabase division driftless area dyke eastern sandstone Emmons epidote evidence fact fauna feet feldspar formation fossils gabbro genera genus Geol geological survey geologists grained granites granular Hall hornblende Huronian Iowa islands James Keweenaw lake layers limestone lower magnetite mass miles Miller minerals Minnesota Missouri mountains natural nearly occur Ohio olivine original orthoclase palæontological plagioclase plates polysomatic porphyries portion Potsdam present primordial probably Prof quartz quartzyte reef referred region river rocks sandstone schists scientific shales shell shore side Silurian slates species specimens strata stratigraphic structure subsidence surface Taconic system theory thickness tion Ulrich unconformably upper valley Walcott Winchell York zoœcia
Sivu 254 - ... philosophical, educational, scientific, or literary purposes, or for the encouragement of the fine arts, or for the use or by order of any college, academy, school or seminary of learning in the United States...
Sivu 218 - The interest excited was intense, but the subject was too novel and too ominous for the old school to enter the lists, before armouring. After the meeting it was talked over with bated breath : Lyell's approval, and perhaps in a small way mine, as his lieutenant in the affair, rather overawed the Fellows, who would otherwise have flown out against the doctrine.
Sivu 155 - s lectures on Geology and Zoology, but they were incredibly dull. The sole effect they produced on me was the determination never, as long as I lived, to read a book on geology, or in any way to study the science.
Sivu 394 - According to the terms of the trust, a bronze medal, and the balance of the interest arising from the fund, are to be awarded annually for the best publication, exploration, discovery, or research in the sciences of geology and paleontology, or in such particular branches thereof as may be designated. The award, and all matters connected therewith, are to be determined by a committee to be selected in an appropriate manner by the academy.
Sivu 156 - Idwal, examining all the rocks with extreme care, as Sedgwick was anxious to find fossils in them; but neither of us saw a trace of the wonderful glacial phenomena all around us: we did not notice the plainly scored rocks, the perched boulders, the lateral and terminal moraines. Yet these phenomena are so conspicuous that, as I declared in a paper published many years afterwards in the Philosophical Magazine, a house burnt down by fire did not tell its story more plainly than did this valley.
Sivu 236 - Magnesian slate, from its containing magnesia, a fact which is distinctly indicated by the soft feel peculiar to rocks when this earth forms a constituent part. 4. Sparry limestone, generally known as the Sparry limerock.
Sivu 368 - ... and must hence extinguish the light between crossed nicols together. Such a structure is termed, according to the particular form it assumes, micropegmatitic or granophyric. In the third place a single large crystal of one of the two constituents of the groundmass may be filled with much smaller, irregularly arranged grains or crystals of the other. This would also give the general effect of a finely granular structure, although it is essentially different from either of the others above mentioned.
Sivu 62 - ... the organic matter passes at once into this or allied products. It is the result of the primary decomposition of organic matter. 3. The organic matter still contained in the rocks can be converted into gas and oil by destructive distillation, but so far as we know, in no other way. It is not capable of furnishing any new supply of petroleum under normal conditions. 4. Petroleum is, in the main, contemporaneous with the rocks that contain it. It was formed at or about the time that these strata...
Sivu 253 - Books, maps, and charts specially imported, not more than two copies in any one invoice, in good faith, for the use of any society incorporated or established for philosophical, literary, or religious purposes, or for the encouragement of the fine arts, or for the use or by order of any college, academy, school, or seminary of learning in the United States.
Sivu 160 - Geology had been influenced by the assumption that the analogy was slight in kind, and still more slight in degree, between the causes which produced the former revolutions of the globe, and those now in every-day operation. It appeared clear that the earlier geologists had not only a scanty acquaintance with existing changes, but were singularly unconscious of the amount of their ignorance. With the presumption naturally inspired by this unconsciousness, they had no hesitation in deciding at once...