303 



The length of the individual bands is more or less propor- 

 tional to their width. Some of the bands, especially the 

 narrower and finer grained, gradually pinch out, but others, 

 notably the wider, coarser grained ones, end abruptly and 

 irregularly. The sides of the bands are usually straight but 

 are sometimes broadly curved and more rarely contorted. 

 The contacts between the bands, while usually well marked, 

 are not sharp in detail, but the crystals of one band are 

 intergrown with those of the continuous bands. In places 

 the Wark gneiss appears to be cut not only by salic 

 apophyses of the Colquitz gneiss but by hornblendite 

 apophyses, which seem to be intrusive and cross cutting. 

 The relations however are so complex and the resemblance 

 of the supposed hornblendite apophyses to the recrystallized 

 Wark gneiss is so close that the intrusive nature of the 

 hornblendite masses can not be positively affirmed. It is 

 concluded that the banded Colquitz gneiss is of primary 

 origin ; that in part the salic and femic bands are true mag- 

 matic differentiates, the intrusive magma having been split 

 into the salic and femic facies before it became too viscous for 

 the separated facies to be pulled out into bands by continued 

 movements in the differentiated magma; and that some 

 of the wide, coarser grained bands are recrystallized and 

 pulled out inclusions of the Wark gneiss. 



The Saanich granodiorite is clearly intrusive into the 

 Wark gneiss and doubtless is younger than the Colquitz 

 gneiss. It brecciates the Wark gneiss, forming extensive 

 areas of "contact complex", consisting of shatter breccias 

 and networks of granodiorite and aplite apophyses in the 

 gabbro-diorite gneiss. 



The diorite porphyrites are younger than the granitic 

 rocks. It is seen that the eruptive cycle, represented by 

 all of the igneous rocks, the Vancouver meta-volcanics, 

 the granitic rocks, and the diorite porphyrites, conforms to 

 the general eruptive cycle, which consists of three phases 

 of igneous activity in the following sequence : the volcanic 

 phase; the batholithic phase; and the phase of minor 

 intrusives. 



The granitic rocks were irrupted into the rocks of the 

 Vancouver group apparently in a relatively quiet manner, 

 and have replaced them without disturbing them greatly. 

 The invading magmas, even during their last active stages, 

 shattered the invaded rocks along their contacts into 

 angular fragments. Near the present contacts great 



