460 



DEPARTMENT OF TEE INTERIOR 



2 GEORGE V., A. 1912 



oh'goclase, Ab 3 An 15 orthoclase (often microcline), and biotite; the accessories, 

 apatite and magnetite, with rather rare titanite and zircon. The order of 

 crystallization is that normal for granites. Sometimes, and especially along con- 

 tact walls, the rock is porphyritic, with the microperthite developed in large idio- 

 morphic and poikilitic phenocrysts, which/ as described by Calkins, weather out 

 with a retention of the crystal form. 



A type specimen (No. 1388) collected on the Commission trail near the top 

 of Bauerman ridge, has been analyzed by Mr. Connor, with result as follows: — 



Analysis of Cathedral granite, Older phase. 



Si0 2 



Ti0 2 



A1 2 0, 



Fe 2 3 



FeO 



MnO 



MgO 



CaO 



BaO 



Na 2 



K 2 



H 2 at 105°C. .. 

 H 2 above 105°C. 

 P 2 8 



Mol. 



Sp. gr. 



71.21 1 



187 



•16 



002 



15-38 



151 



•25 



001 



147 



021 



.06 



001 



•33 



008 



1-37 



024 



•09 



001 



4-28 



069 



4-85 



051 



•02 





•43 





•05 



... 



99-95 





2-621 





The calculated norm is : 



Quartz 



Orthoclase. . 



Albite 



Anorthite. . . 

 Corundum. . 

 Hypersthene. 

 Magnetite. . 

 Ilmenite.. .. 

 Water 



23-46 



28-36 



36-16 



6-95 



•61 



3-18 



•46 



•30 



•45 



99.93 



The mode (Rosiwal method) is approximately: — 



Quartz 35-7 



Orthoclase 7-0 



Microperthite 40-3 



Oligoclase 11-0 



Biotite 5-0 



Magnetite and titanite »7 



Apatite -3 



100-0 



