PETROGRAPHIC GEOLOGY AND DESCRIPTIONS. 863 



Granite. Gneiss. Greenstone.] 



Remark. The relation of this rock to the adjacent red rock forming the so-called 

 " palisades," could not be exactly determined, but if the red dikes in this are from 

 the red rock, as apophyses, as seems probable, this is the older rock. N. H. w. 



No. 2222. GRANITE. ( HornUendic. ) 



Same place and same rock mass as the last. 

 Ref. Annual Report, xxiv, page 68. 



Meg. Finer grained condition of No. 2221, having a schistose direction in the 

 arrangement of the hornblendes. 



Mic. This rock is more abundantly supplied with hornblende, but less with 

 quartz. One section. 



Age. Archean. N. H. w. 



No. 2225. GNEISS. 



N. E. % S. W. % sec. 24, T. 63-10, on the portage from Kawishiwi river to Triangle lake, near the Kawishiwi. 

 Ref. Annual Report, xxiv, page 68. 



Meg. Schistose, fine interlamination of green, apparently chloritic, interrupted 

 sheets with red, fine-gi'ained, broader sheets which appear to be granitic, the whole 

 having the aspect of fluidal structure, or of a transition from the granite to the 

 greenstone, the former existing toward the south and the latter toward the north. 

 As constituents of the red-weathering sheets are a few roundish masses visible on 

 the weathered surface, resembling orthoclase phenocrysts. The fresh fracture of this 

 rock is gray rather than green. 



^fir. The rock is in general a granular mass of fine gwarfeand hornblende, with 

 feldspar both orthoclase and plagioclase. There are numerous ragged feldspars of 

 larger size, interlocking with the finer matrix about their margins. The hornblendes 

 are small and ragged, and in places magnetite and biotite unite with it in composing 

 the darker laminae. Some fine apatite and also rutile are scattered irregularly 

 through the slide. One section. 



Age. Archean. 



lie/nark. From the microscopical characters it appears that this megascopic 

 laminated structure is probably due to the shearing of an igneous rock (granite). 



N. H. w. 

 No. 2226. GREENSTONE. 



From a large inclusion in granite, near the same place as No. 22l'r>. 

 Ref. Annual Report, xxiv, page 68. 



Meg. Fine grained, dense, hardly showing any structure, yet on the weathered 

 surface the hornblendes and feldspars are seen to have one direction. 



Mic. The larger hornblendes are ragged and irregularly interlock with and 

 partially enclose some of the feldspars. It is apparent that they are secondarily 



