W. G. Foye — Nephelite Syeyiites of Ontario. 423 

 Its position in the norm classification is therefore : — 



Class III Dosalane 



Order 6 N orgare 



Rang 2 Essexase (near Salemase) 



Sub-ran g 4 Essexose 



2. Hornblende-Nephelite Rock. 



Macroscopic description. — The hornblende-nephelite rock 

 is mottled black and white and contains occasional grains of 

 garnet from 1 to 5 mm. in diameter. 



The jet black hornblende grannies are arranged in irregular 

 masses or lines with bits of feldspar or nephelite lying between 

 them. 



The nephelite has the creamy white color it assumes when 

 slightly decomposed. 



Microscopic description. — The thin section cut from this 

 rock does not correctly represent the relative amounts of its 

 constituent minerals. A comparison of the section and the 

 hand specimen gave the following approximate percentage 

 composition : — 



Nephelite 30 - per cent 



Albite 7-0 



Hornblende 30'0 



Pyroxene.. 20*0 



Garnet 7 '5 



Calcite 5-0 



Apatite -5 



100-0 



The nephelite occurs as large irregular grains. 



The albite is in minute rounded crystals, within or adjacent 

 to the nephelite. 



The hornblende is deeply pleochroic, dark bluish green to 

 brown. 



The pyroxene is apple-green in color. It is much shattered 

 and the cracks are healed by an epidote, or, sometimes, garnet. 



The rock as a whole shows granulations under pressure. 



Chemical description. — Adams and Barlow give the follow- 

 ing analysis for their type II, which is approximately the same 

 as this rock : — 



