358 DEPARTMENT OF THE INTERIOR 



2 GEORGE V, A. 1912 

 Calculated norm : — 



Orthoclase 30-02 



Albite 20-96 



Anorthite 10-84 



Nephelite 1-13 



Diopside 16-74 



Olivine 12-45 



Magnetite 3-71 



Ilmenite 1-36 



Apatite 1-24 



Water -66 



9911 



The mode (Rosiwal method) i 



s approximately: — 



.... 45-1 







.... 10-6 







.... 24-5 







.... 10-7 







.... 1-7 







.... 3-5 







.... 3-5 







.... -4 



100-0 



According to the Norm, classification the rock enters the sodipotassic sub- 

 iang, monzonose, of the domalkalie rang, monzonase, in the dosalane order, 

 germanare. According to the older classification the rock is a porphyritic 

 biotite-bearing augite-olivine syenite of an unusual variety. Chemically it is 

 closely allied to olivine monzonite and, in many respects, to shonkinite. It 

 is almost identical with the average minette of this region. The average of the 

 three minette analyses noted in the last chapter is given in Col. 2 of Table 

 XXIV. From the comparison of Cols. 1 and 2 one is led to suspect that this 

 abnormal syenite really represents a minettic magma which, because of the large 

 size of each of the bodies in which it occurs, crystallized with its peculiar 

 structure. It may be true, however, that the remarkably fresh and quite 

 uncrushed olivine-syenite is geologically much younger than most of the minette 

 dikes of the Selkirks. 



Coryell Syenite Batholith. 



Between Record mountain ridge and Christina lake the greater part of the 

 ten-mile belt is covered by a batholith of syenitic rock which is generally quite 

 uncrushed and, like the Sheppard granite, is among the most recent of the 

 intrusives in the Columbia mountain system. The Coryell railway station is 

 situated near the northern contact; the intrusive mass may be called the 

 Coryell batholith. 



Though this batholith is marked in the West Kootenay reconnaissance 

 sheet with the same colour as the various stocks of the Sheppard granite, there 



