. The Nepheline and Associated Alkali Syenites of Eastern Ontario . bove that required and whicliappears in the norm as quartz. By direct evperiment it was subse-quently shown that most, if not all, of this silica was derived from theagate mortar and pestle which was used in grinding the sample. Thereis no free silica or quartz shown in the thin sections, nor was any of thismineral found in the separation of the rock by means of the heavy solu-tion. The mode or actual mineralogical composition cannot be calculatedwith certainty on account of the presence of the two micas and theBcapolite, the
. The Nepheline and Associated Alkali Syenites of Eastern Ontario . bove that required and whicliappears in the norm as quartz. By direct evperiment it was subse-quently shown that most, if not all, of this silica was derived from theagate mortar and pestle which was used in grinding the sample. Thereis no free silica or quartz shown in the thin sections, nor was any of thismineral found in the separation of the rock by means of the heavy solu-tion. The mode or actual mineralogical composition cannot be calculatedwith certainty on account of the presence of the two micas and theBcapolite, the latter having about the same formula as the feldspar. Thecorundum, magnetite and calcite are normative, , they are presentessentially in the percentages given in the norm. From an inspection ofthe slides the following would seem to be a very close approximation tothe mineralogical composition of the rock:— Andesine (near z\.b,An,) Nepheline 3. 00 Scapolite Corundum (by trial) Biotite Muscovite 3. 00 Magnetite Calcite .37 05. [ADAMS A BARLOW] ALKALI SYENITES OF EASTERN ONTARIO 67 Owing to the large percentage of corundum present, the rock is avery peculiar and unusual one, and represents a new sub-class, order,rang and sub-rang in the Quantitative Classification. We accordinglypropose the following names for the new order and rang, and the nameDungannonite for the rock itself: Class I Persalane Sub-class II (Section I) Dosalone Order 5 Indare Eang 3 Dungannonase Sub-rang 4 Dungannonose An analysis of the andesine occurring in the rock was made by F. Connor, This is given under I. The material for theanalysis was obtained by separating the feldspar with Thoulets was somewhat impure, owing mainly to the admixture of a smallamount of biotite. This accounts for the iron, potash and magnesiafound in the analysis. Neglecting these, the composition correspondsrather closely to that of an andesine with the formula AbgAug. T
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