38 ROYAL SOCIETY OF CANADA 



Its position in the Quantitative Classification is as follows : — 



Class III Dosalane. 



Order 6 Norgare. 



Rang 2 Essexase (very near Salemase). 



Sub-rang 4 Essexose. 



Its mode or actual mineralogical composition is as follows : 



Orthoclase 2.78 per cent. 



Albite 22.27 \ 23 94 " 



Anorthite 1.67/ 



Nepheline 15.91 \ 26 23 '' 



Kaolin 10.32/ 



Hornblende 39.75 



Apatite .34 



Calcite 5.50 



98.54 

 Water 1.10 



99.64 



Nepheline syenite — TownsJdp of Monmouth — Lot 11, Con. VIII. 

 {Second Variety). 



This is rich in nepheline and contains a large percentage of py- 

 roxene. It is much lighter in colour, but otherwise bears a general re- 

 semblance to the variety just described. Under the microscope all the 

 constituents are seen to be fresh, but they frequently show signs of hav- 

 ing been submitted to pressure, as shown by the presence of a more or 

 less uneven extinction. This is especially marked in the case of the 

 calcite, and the albite can in some few instances be seen to have been 

 not only bent but actually fractured. The nepheline also occasionally 

 shows strain shadows. As before, no microcline nor microperthite is 

 present in the sections and a Thoulet separation shows that the rock 

 contains no potash feldspar. The albite has a specific gravity of very 

 nearly 2.61. 



The pyroxene is very deep green in colour and somewhat ])loocliroic. 

 Around the individuals of this mineral and occasionally about the cal- 

 cite grains, there is sometimes a narrow border of garnet. Tlie pyroxene 

 is evidently very rich in iron and holds rounded inclusions of calcite and 

 nepheline. 



