Summarized Proceedings and a Directory of Members, Volumen20


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Página xiv - The Association shall meet, at such intervals as it may determine, for one week, or longer; and the arrangements for it shall be intrusted to the officers and the Local Committee. The Standing Committee shall have power to determine the time and place of each meeting, and shall give due notice of it to the Association.
Página 46 - crinoidal stems and plates in a paleozoic limestone from New Brunswick, which is made up of organic remains. This silicate, which, in decalcified specimens, shows in a beautiful manner the intimate structure of these ancient crinoids, I have found by analysis to be a hydrous silicate of alumina and ferrous oxyd, with magnesia and alkalies,
Página 44 - analogy, moreover, leads us to conclude that even at this early period, life existed at the surface of the planet. Great accumulations of iron-oxyd, beds of metallic sulphids, and of graphite, exist in these oldest strata, and we know of no other agency than that of organic matter, capable of generating these products.
Página 40 - inquiries in this direction may show to what extent certain rocks composed of calcareous and magnesian silicates may be directly formed in the moist way."* Subsequently, in a paper on "The Origin of some Magnesian and Aluminous Rocks," printed in the " Canadian Naturalist
Página 44 - Bischof had already arrived at the conclusion, which in the present state of our knowledge seems inevitable, that " all the carbon yet known to occur in a free state, can only be regarded as a product of the decomposition of carbonic acid, and as derived from the vegetable kingdom.
Página 48 - which abound in the ancient crystalline schists. Thus, while the materials for producing, by diagenesis, the aluminous silicates just mentioned, are to be met with in the mud and clay-rocks of all ages, the chemically formed silicates, capable of crystallizing into pyroxene, talc, serpentine, &c., have only been formed under special conditions.
Página 307 - through that order. There are great varieties of type in subordinate features, to be found in the Nematognathi. The affinity of the catfishes to the sturgeons is seen in the absence of symplectic, the rudimental maxillary bone, and, as observed by Parker, in the interclavicles. There is a superficial resemblance in the dermal bones.
Página 47 - These conditions must have favored many chemical processes, which, in later times, have nearly ceased to operate. Hence we find that subsequently to the eozoic times, silicated rocks of clearly marked chemical origin are comparatively rare. In the mechanical sediments of later periods certain crystalline minerals may be developed by a process of molecular rearrangement—diagenesis. These are, in the
Página 246 - 400 miles from east to west, and 500 miles from north to south, bounded on the north by the river Rio Grande. Some of the villages and haciendas are specified in the diagram, and the numbers 1, 2, 3,
Página 2 - nacreous slates, though analysis shows them not to be magnesian, but to consist essentially of a hydrous micaceous mineral. They are sometimes black and graphitic. III. The White Mountain Series. — This series is characterized by the predominance of well-defined mica-schists, interstratified with micaceous gneisses. These latter are ordinarily

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