436 DEPARTMENT OF THE INTERIOR 



2 GEORGE V., A. 1912 



The calculated norm is : — 



Orthoclase 2-78 



Albite 30-39 



Anorthite .. 33-08 



Hypersthene 10-71 



Diopside 6-56 



Olivine ■ 6-70 



Ilmenite 4-26 



Magnetite 3-25 



Apatite 1-86 



Water -65 



100-24 



The mode (Rosiwal method) is approximately : — 



Labradorite ,.- 57-5 



Hornblende 21-8 



Augite 12-0 



Biotite 3-0 



Magnetite : 3-6 



Apatite l - 6 



Qtiartz -5 



100-0 



In the Norm classification the rock enters the presodic subrang, hessose, of 

 the docalcic rang, hessase, in the dosalane order, germanare. In the older classi- 

 fication it is an augite-hornblende-biotite gabbro. The specific gravities of two 

 fresh specimens average 2-946. 



Although the gabbro is older than the Remmel granodiorite and has shared 

 in the great dynamic metamorphism which, as .we shall see, has profoundly 

 affected the more acid rock, there is far less crushing action manifest in the 

 gabbro than in the granodiorite. Gneissic structures were indeed sometimes 

 seen in the ledges, but banding was never discovered, and the granulation is 

 seldom comparable to that of the Remmel. It is, moreover, suspected that some 

 of the gneissic arrangement of minerals in the gabbro is due to fluidal align- 

 ment of its tahular. feldspars in the original magmatic period. Tor some un- 

 known reason the gabbro has resisted crushing and shearing better than the 

 granodiorite. 



Basic Complex. 



Petrographically and structurally, the Basic Complex is perhaps the most 

 steadily variable plutonic mass in the entire Boundary section from the Great 

 Plains to the Pacific. It covers an area stretching from Ashnola river westward 

 over Park Mountain ridge, a distance of five miles. The extreme north-and- 

 south diameter is about three miles, and the total area is nearly seven square 

 miles. The Remmel granodiorite once completely surrounded the Complex, 

 which, as above noted, is in pendant relation to the batholith. The pre-Remmel 

 extent of the Complex was greater than the area now exposed; how much of it 

 was destroyed during the Remmel intrusion it is impossible to say. The part 

 thus remnant was still further diminished during the intrusion of the Park 



