538 DEPARTMENT OF THE INTERIOR 



2 GEORGE V., A. 1912 

 The calculated norm is : — 



Quartz 2916 



Orthoclase 17-79 



Albite 34-58 



Anorthite 11-68 



Corundum -K) 



Hypersthene 3-33 



Magnetite 1-86 



Ilmenite -61 



Apatite -31 



Water and C0 2 -51 



99-93 



The mode (Rosiwal method) is approximately: — 



Quartz 34-1 



Orthoclase and microperthite 25-7 



Oligoclase 30-2 



Biotite 8-1 



Magnetite 1-1 



Titanite -4 



Apatite r3 



Zircon •! 



100-0 



In the Norm classification the rock enters the dosodic subrang, lassenose, of 

 the domalkalic rang, toscanase, in the persalane order, britannare. In the older 

 classification it is a biotite granite with dominant oligoclase — a soda granite. 



So far as observed, this rock occurs only on the north side of Chilliwack 

 valley and north of the lake. It may conceivably represent a distinct intrusive 

 body, bearing the same relation to the hornblende-labradorite phase of the main 

 batholith as the Cathedral granite of the Okanagan range bears to the Similka- 

 meen granodiorite. Yet no sharp contact between the granite and diorite phases 

 was found, and the writer has concluded that both probably belong to the one 

 batholith. It is of some interest to note that the arithmetical mean of the two 

 analyses is almost the exact equivalent of the analysis of the average grano- 

 diorite in the Cordillera. The latter average appears in column 4 of the follow- 

 ing Table XXXIII, and represents nine analyses from California types, one 

 Oregon type, and two Washington types, all of these being taken from Bulletin 

 No. 228 of the United States Geological Survey. 



