. The Nepheline and Associated Alkali Syenites of Eastern Ontario . plagioclase varying from albite through oligoclase toandesine is the prevalent and often the only feldspathic Adams^ in his paper announcing the discovery of these occurrencesin the townships of Dungannon and Faraday, made reference to this asfollows.— If the distinctive character of the nepheline syenite namedLitchfleldite by Bayley be the replacement of the orthoclase by albite,this rock is a more typical Litchfleldite than that from the original local-ity. The propriety of defining nepheline syenite as a roc
. The Nepheline and Associated Alkali Syenites of Eastern Ontario . plagioclase varying from albite through oligoclase toandesine is the prevalent and often the only feldspathic Adams^ in his paper announcing the discovery of these occurrencesin the townships of Dungannon and Faraday, made reference to this asfollows.— If the distinctive character of the nepheline syenite namedLitchfleldite by Bayley be the replacement of the orthoclase by albite,this rock is a more typical Litchfleldite than that from the original local-ity. The propriety of defining nepheline syenite as a rock composedessentially of nepheline and an alkali feldspar, instead of one composedof nepheline and orthoclase is rendered evident, as otherwise it would benecessary to classify this rock as a theralite from typical specimens ofwhich it would differ greatly in composition. These various rocks, while sometimes quite massive, possessing atrue hypidiomorphic granular structure, usually have a more or less per- American Journal of Science, vol. XIAIII, 1894, p. [ADAMS A BARLOW] ALKALI SYENITES OF EASTERN ONTARIO . 11 feet foliated structure which in many places presents an actual schistosedevelopment, the strike of which conforms to that of the adjacent countryrock. The foliation has all the characters of an original vary in texture from medium to coarse grained, while the peg-matitic phases sometimes present nepheline and plagioclase individualsas much as a yard in diameter. The rock is, as a rule, remarkably fresh and unaltered. Evidences ofpressure even in the most pronouncedly foliated or schistose varietiesare extremely rare. In occasional instances, however, some of the feld-spars show strain shadows and curved or slightly dislocated twinninglamellae. Sections of the rock comprising the narrow part of the band,crossing the J\Ionck road in Faraday township, show quite pronouncedgranulation and cataclastic structure. The relations of the constituent mineral
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