PETKOGRAPHIC GEOLOGY AND DESCRIPTIONS. 767 



Gabbro. Slate. Greenstone.] 



Mic. The slide consists entirely of hypersthene, but with numerous globular 

 inclusions of quartz and apparently of labradorite. One section. 



Age. Cabotian. An accident of the gabbro. N. H. w. 



No. 1713. GABBRO (with olivine). 



Same place as No. 1710. 



Ref. Annual Report, xxi, page 156. 



Meg. A medium-grained gabbro, composed of feldspar, augite, hornblende and 

 apparently olivine. Biotite and pyrite are also present. No section. 



Age. Cabotian. u. s. G. 



No. 1714. SLATE. 



Same place as No. 1710. 



Ref. Annual Report, xxi, page 15G. 



Meg. Hard, fine-grained, black, minutely banded, siliceous and magnetic slate, 

 crossed by many quartz veinings. No section. 



Age. Probably a dark jaspilyte of the Keewatin. u. s. G. 



No. 1717. GABBRO. (Miuscovadyte.) 



N. W. J S. E. J sec. 19, T. 63-9, Kawishiwi river, south side. 

 Ref. Annual Report, xxi, page 156. 



Me*]. Fine grained. The structure stands vertical. 



Mic. The slide consists apparently wholly of olivine and plagioclase. One 

 (thick) section. 



Age. Cabotian. N. H. w. 



No. 1721. GREENSTONE. (Granular and yr My.) 



Sec. 34, T. 64-9 W., Snowbank lake. From near the granite. 

 Ref. Annual Report, xxi, pages 97, 156. 



Greenstone, appearing coarse and feldspathic. 



Mic. The large feldspars are striated, but also considerably altered. They have 

 ragged edges, due to decay, that interlock in a ragged, dentate manner with the 

 surrounding matrix, but they do not interfere nor interlock with one another. They 

 are not perceptibly zoned. They contain numerous minute inclusions uniformly 

 distributed, resulting from alteration, chiefly sericite, but occasionally fresh glassy 

 grains, evidently of some feldspar, which extinguish differently. Similar fresh feld- 

 spars are scattered generally throughout the fine matrix. 'Quartz appears as rather 

 large grains in a manner similar to that of the feldspars, but has evident secondary 

 enlargements, while green hornblende is so abundant as to have given name to the 

 rock. It is in fine shreds and ragged masses, and shows no common structure or 

 direction. Hexagonal apatite crystals rarely appear. One section. 



Aye. Keewatin. 



