440 



DEPARTMENT OF THE INTERIOR 



2 GEORGE V., A. 1912 



it becomes abundant the iron ore has partially or wholly disappeared; then 

 probably entering into the composition of the epidote. Biotite is generally 

 dominant over hornblende and plagioclase over orthoelase. 



A fresh specimen nearly representing the original granodiorite was collected 

 at a point two miles north of the Boundary line and about two miles from the 

 eastern contact of the batholith. This specimen is rather coarse-grained and is 

 gneissic, though not so schistose as the average rock of the batholith in the 

 observed exposures. The essential and accessory minerals are those named in 

 the foregoing list; biotite is more abundant than hornblende and plagioclase 

 than orthoelase. This specimen (No. 295) was analyzed by Mr. Connor, with 

 the following result: — 



Analysis of Osoyoos granodiorite. 



Mol. 



Si0 2 6843 1-140 



Ti0 2 -20 -003 



Al.,0, 15-80 -155 



Fe-A 1-08 -007 



Feb 1-85 -025 



MnO. -10 -001 



MgO 1-46 -036 



CaO 4-08 -073 



SrO.. -02 



BaO -09 -001 



Na 2 3-47 -056 



K 2 2-51 -027 



H 2 at 105°C -05 



H 2 above 105°C -53 



P 2 O n -07 -001 



99-72 

 Sp. Ei' 2-708 



The calculated norm is: — 



Quartz 26-82 



Orthoelase 15-01 



Albite 29-34 



Anorthite 19-74 



Hypersthene 5-61 



Diopside -23 



Magnetite 1-62 



Ilmenite .46 



Apatite -31 



Water 58 



99-72 



The mode (Rosiwal method) is approximately: — 



Quartz 37.O 



Orthoelase 7.5 



Andesine 33.I 



Biotite 10-8 



Hornblende , 3-1 



Epidote 8-0 



Titanite .3 



Apatite .1 



Zircon .1 



100-0 



