THE LOWER HURONIAN. 355 



mally found cutting the greenstone wdiich borders t]ie Giants Range granite 

 on the north. They are described with the Giants Range granite, since they 

 are presumed to be offshoots from it, although their direct field connection 

 with it can not be shown. Their petrographic. similarity to the main 

 granite mass seems alone sufficient to warrant their description together 

 and to supjDort the view that they were derived from the same deep-seated 

 source. 



In places along the Kawishiwi River the granite is slightly schistose. 

 This schistosity is especially noticeable along the margin of the granite, 

 where it lies next to the Archeau Ely greenstone. These schistose phases 

 can be well seen in the southern half of sec. 24, T. 63 N., R. 10 W., imme- 

 diately north of the Kawishiwi River. 



The granite massive includes areas of dark hornblende and mica rocks 

 which are more or less schistose and consist of hornblende, mica, quartz, 

 and feldspar in about equal proportion. The relationship which the granite 

 is presumed to have to these is indicated by the use above of the word 

 "includes," for it surrounds these masses in some cases and sends oifshoots 

 into them. In other cases the granite is found cementing an eruptive 

 breccia the fragments of which were derived from the above-mentioned 

 schists. Such a breccia, for example, is well shown' just north of Clear- 

 water Lake, alongside the portage entering that lake from the Kawishiwi 

 River. These fragments in the granite are in some cases derived from the 

 Ely greenstone. In other cases the fragments represent a sedimentary series, 

 the Lower Huronian, which has been intruded and included by the granite. 

 It is difficult to determine the original characters of these included rock 

 fragments from a microscopic study after they have been metamorphosed. 

 In the field one has as a guide the proxunity of the granite to larger masses 

 of metamorphosed sediments on the one hand or to the Ely greenstone 

 on the other. Naturally the fragments in the granite are most likely to 

 have been derived from that rock to which the fragments are nearest. 



Dikes of very fine-grained red aplite cut the Giants Range granite. 



The constituents of these granitic rocks as disclosed by the microscope 

 are orthoclase (microcline), plagioclase, quartz, hornblende, mica, zircon, 

 apatite, sphene, a little iron ore. These minerals possess their usual char- 

 acters. It is interesting to note that the microcline is especially abundant 

 in granites which show the pressure effects in the other minerals more evi- 



