456 DEPARTMENT OF THE INTERIOR 



2 GEORGE V., A. 1912 



Analysis of dominant phase, Similkameen batholith. 



Mol. 



Si0 2 66-55 1-109 



Ti0 2 -40 -005 



A1 2 0, 16-21 -159 • 



Fe 2 O s 1-98 -013 



FeO 1-80 -025 



MnO -12 -001 



MgO 1-32 -033 



CaO 3-86 -069 



SrO -01 



BaO -03 



Na 2 4-07 -066 



K 2 2-84 -030 



H 2 at 105°C 01 



H,0 above 105°C -24 



P 2 B .. -15 -001 



99-59 

 Sp. gr 2-693 



The calculated norm is : — 



Quartz 21-78 



Orthoclase 16-68 



Albite 34-58 



Anorthite 17-51 



Hypersthene 4-05 



Diopside '64 



Magnetite 3-02 



Ilmenite.. «76 



Apatite -31 



Water «25 



99-58 



The mode (Eosiwal method) is approximately: — 



Quartz. 22-0 



Orthoclase and microcline 6-7 



Microperthite 27-0 



Oligoclaee 29-8 



Biotite 5-5 



Hornblende 4-2 



Magnetite 1-8 



Titanite 1-1 



Epidote 1-1 



Apatite -8 



100-0 



In the Norm classification the rock enteres the dosodic subrang, yellow- 

 stonose, of the alkalicalcic rang, coloradase, in the persalane order, britannare. 



In the older classification it is a granodiorite, though the dominance of 

 microperthite and the relative acidity of the soda-lime feldspar allies the rock to 

 the alkaline granites. 



For many square miles together the great central portion of the batholith 

 is composed of this rock — a soda-rich biotite-hornblende granite or granodiorite 

 of an average specific gravity of 2-706. 



At the head of Toude (or Toat) coulee the rock of a large area within the 

 batholith is generally porphyritic and distinctly finer grained than the staple 



