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 gneiss at points directly opposite each other, 

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



Fig. 9. 



Schistose dyke, between two g-ranitic dykes, cutting- and faulting- g-neiss Sabascosing 

 Bay, Lake of the Woods. 



1. Granite dyke, 9 feet wide. 



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



3. Granite dyke, about 1 foot wide. 



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



schists a very scliistose dyke of a 



rock, composed of hornblende, mica 



; and feldsjoar, containing brecciated 



: fragments of a highly feldspathic 



gray granite (Fig. 10). The dyke is 



j fi-om two to four feet wide, and 



traverses the schists across their 



strike. The included fragments are 



not numerous, but present the 



ter. ..^.-^^.^^^>i-r,,jm-^^...^^^^^..: 



Pie. 10. 

 aspect of true brecciated inclusions. 



These instances appear to prove conclusively that a gneissic folia- 

 tion may be developed in a granitic 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 original 



