PETROGRAPHIC GEOLOGY AND DESCRIPTIONS. 657 



slati-. Breccia. Biotite schist.] 



BilititO Hll' 1 !**- 



No. 10H<j. SLATE. (Bkiuk.) 



Near the same locality as No. 1085. 

 Ref. Annual Report, xv, pages 37G, 397. 



Meg. A very fine-grained, siliceous, black slate. No section. 



Age. Archean (Keewatin). u. s. G. 



No. 1087. BRECCIA. 



Portage from Pox to Ash lake. The specimen came from near the southwest corner of sec. 25, T. G5-6 W. 

 Ref. Annual Report, xv, pages 377, 397. 



Meg. A breccia of fine-grained, gray, siliceous slate and a coarser, gritty rock, 

 the latter including fragments of the former. No section. 



Age. Archean (Keewatin). u. s. G. 



No. 1088. BIOTITE SCHIST (with quartz). 



North shore of Gabemichigama lake. Prom an island at the entrance to the bay running northeast ; S. W. 

 J sec. 29, T. 65-5. 



Ref. Annual Report, xv, pages 379, 397 ; Annual Report, xxi, page 147. 



4 



Mey. Quartzitic slate, having a columnar aspect. 



Mlc. Biotite is very conspicuous, also angular quartzes. These lie in a finer 

 matrix of quartz grains which also has some of striated feldspar. The quartz is 

 secondary to the biotite, and partially incloses it poikilitically, having been entirely 

 recrystallized. One section. 



Age. Archean (Keewatin). N. H. w. 



No. 1089. BIOTITE SCHIST (with 



North side of the long point, S. W. % scc - 32. T. 6"> 5, C.abemichigama lake. 

 Ref. Annual Report, xv, pages 379, 380, 397 ; Annual Report, xxi, page 147. 



Mc(j. Siliceous, fine grained, rather dark, in heavy layers. 



Mic. In a fine background of secondary granular quartz are numerous biotite 

 leaves, and a debris from basic rock consisting now in part of actinolite in fibres and 

 occasionally in bundles of fibres, but most abundantly of scattered granular or 

 globular particles, which are also embraced in the enlargements of the quartz. In 

 the form of grains and minute particles this element mingles widely with the quartz- 

 ose matrix and is evidently some form of pyro.rene. One (thick) section. 



Af/e. Archean (Keewatin). N. H. w. 



No. 1090. BIOTITE GNEISS (orwhM, iriili 



South shore of the same long point, Gabemichigamu lake. 



Ref. Annual Report, xv, pages 379, 380, 397 ; Annual Report, xxi, page 148. 



Siliceous, gneissic, with evident biotite. 

 M ic. This rock is like the last, but is coarser and has a monoclinic pi/r<>.u'it<-. 

 The secondary quartzes form large crystals that embrace the earlier grains of ron/irn'f<' 

 and this regenerated ferro-magnesian debris poikilitically. Many of the glassy grains 

 thus embraced are apparently of oligoclase-andesine. They not only show a fine 



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