122 



PROCEEDINGS OF THE CANADIAN INSTITUTE. 



between two other dykes of fine-grained gray granite, one nine feet 

 wide on the north-east side and one one foot wide on the south-west 

 side. All these dykes fault the rock, as is seen by the non- 

 correspondence of the gnei.ss at jjoints directly opposite each other, 

 and by the slight torsions of the nearly vertical planes of foliation. 



W^W. 



Fig. 9. 



Schistose dyke, between two granitic dykes, cutting and faulting gneiss Sabaseosing 

 Bay, Lake of the Woods. 



1. Granite dyke, 9 feet wide. 



2. Dyke of laminated and schistose amphibolite rock— hornblende schist. 



3. Granite djke, about 1 foot wide. 



On the north-west corner of Oak Island there cuts the hornblende 



schists a very schistose dyke of a 

 rock, composed of hornblende, mica 

 and feld.spar, containing brecciated 

 fragments of a highly feldspathic 

 gray granite (Fig. 10). The dyke is 

 fi'om two to four feet wide, and 

 traverses the schists across their 

 strike. The included fragments are 

 not numerous, but present the 



J 



Fig. 10. 



aspect of true brecciated inclusions. 



These instances appear to pi-ove conclusively that a gneissic folia- 

 tion may be developed in a gi-anitic rock that was at one time viscid 

 or flowing enough to be injected within fissures of other rocks; and 

 also that a schistose structure may be developed in igneous intru- 

 sions. Omitting for the moment all considerations as to the causes 

 to which this foliation and schistose cleavage may be ascribed, these 

 conclusions have an important bearing upon the possible oi-iginal 



