Bulletin of the United States Geological SurveyThe Survey., 1903 |
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abundant aggregate albite alkaline apatite Ascutney Mountain augite basic segregations Basic stock bionic values biotite Bull Catskill Cayuga Lake characteristic characters Chemung Chemung formation Chonetes classification composition conditions of environment cordierite correlation County crystals Devonian dike diorite dominant species eastern New York Eighteenmile Creek equivalency eruptive evidence expressed fact faunules feet feldspar fossil faunas fossiliferous zone fossils geographical distribution Geologist gneisses granite Hamilton formation horizon hornblende igneous ilmenite individual intrusive Ithaca formation Jour limestone lithological Little Ascutney living magma Main syenite metamorphic microperthite migration minerals modification nordmarkite occur Oneonta organisms orthoclase paisanite Palæoneilo paleontology particular pennatus phase phyllite porphyritic Productella speciosa quartz region relations Rept rock schists sediments shale spec specific gravity specimens speciosa fauna Spirifer disjunctus fauna statistics strata stratigraphical structure syenite Table tion Titanite Trace Tropidoleptus carinatus fauna Tropidoleptus fauna typical U. S. Geol zircon
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49 페이지 - After the publication of the classification set forth in the paper of 1886 " a large number of investigations were undertaken, not only in New York, but in other parts of the country, which throw new light upon the questions then raised. But nowhere have the statistics been so well gathered as in New York State. Particularly valuable have been the researches of Prof.
104 페이지 - ... of the bottom. If in such case each fauna is kept distinct, the means of tracing the geographic distribution and modification are at hand. If mingled, then the collection, though made at the same locality, will only confuse. Two such faunas meet at Owego, Tioga county, in distinct strata, but in rocks which are of similar lithologic character; one is a remnant of a prevailing western fauna, the other is an eastern and late stage of a new fauna. Fifth. The classification of the rocks may receive...
51 페이지 - The microperthite is especially interesting on account of its typical development. The usual intergrowth is that of orthoclase with a plagioclase varying from albite to an acid oligoclase near Ab5An,, but on many cleavage pieces it was easily proved that the triclinic feldspar was intergrown with a monoclinic, itself strongly charged with the soda molecule. Such individuals gave extinctions of 12° and 19° on (010) for the two kinds of...
7 페이지 - ... at the base of the hill), is strictly controlled in form by a small elliptical stock of alkaline syenite cutting the softer diorites. Apart from other more general considerations, the fact that these eruptive rocks are more resistant to weather than the surrounding schists is clear from the nature of the slopes and profiles at the contacts. As a rule there is an abrupt steepening of the ascent along the radiating spurs of the main mountain just above the contact between the sedimentary and eruptive...
135 페이지 - New or rare species of fossils from the horizons of the Livonia salt shaft [New York].