424: W. G. Foye — Nephelite Syenites of Ontario. 



per cent The calculated norm is : — 



Si0 2 



4:2-72 



Ti0 2 



0-38 



A1,0 3 



25-08 



Fe 2 3 



2-00 



FeO 



4-36 



MgO 



•97 



MnO 



•16 



CaO 



6-92 



Na,0 



11-02 



K 2 



2-69 



PA 



•19 



co, 



2-99 



H 2 



•88 



Ortboclase 



15-57 per cent 



Albite 



7-34 



Anorthite 



10-80 



Nephelite 



40-58 



Diopside 



3-08 



Olivine 



5-10 



Ilraenite 



•76 



Magnetite 



2-78 



Apatite 



•34 



Calcite 



6-80 



99-15 



100-36 



Its position in the norm classification is : — 



Class II Dosalane 



Order 7 Italare 



Rang 2 Vulturase 



Sub-rang 4 Vulturose 



3. Monmoutriite. 



Macroscopic description. — Monmouthite was first described 

 from the laccolith now under discussion.* The rock which is 

 about to be described resembles the type monmouthite but 

 does not contain hornblende (hastingsite) or cancrinite. The 

 original type is very rare in this locality. 



The rock is bluish-gray in color, medium-grained and some- 

 what schistose. It is flecked with minute bits of black mica 

 (1-2 mm. in diameter) which are arranged in sub-parallel 

 layers. 



Microscopic description. — The minerals found in this rock, 

 arranged according to their proportions by weight, are : — 



Nephelite 56-68 per cent 



Scapolite 10-18 



Biotite . _ 22-50 



Albite 9-25 



Kaolin 1-02 



Calcite -37 



100-00 

 F. D. Adams, this Journal, (4), vol. xvii, pp. 272-276, 1904. 



