PETROGRAPHIC GEOLOGY AND DESCRIPTIONS. 581 



Chlorite schist. Jaspilyte ] 



Meg. Similar to No. 868. 



Mic. This is a little finer-grained than Nos. 868 or 868A, but otherwise it is the 

 same in all respects. In the section is one large rounded quartz grain with inclusions 

 of hornblende and calcite. One section. 



Age. Keewatin. N. H. w. 



No. 868F. CHLORITE SCHIST. 



"Gneissic or schistose structure of No. 868, adjacent to No. 868E." 

 Sef. AnnuiJ Report, xv, pages 240, 387; Bulletin vi, pages 43, 421. 



Meg. A fine-grained, greenish to brownish, schistose, rather soft rock. 



Mic. The section, which is quite thick, appears to be composed essentially of 

 small flakes of chlorite and Muscovite and small grains of quartz. The chlorite and 

 muscovite flakes are in general arranged with their long axes in a common direction. 

 Some yellow stain is present in considerable quantity. One section. 



Age. Keewatin. u. s. G. 



No. 868G. CHLORITE SCHIST. 



Same exposed surface with No. 868E. 

 Ref. Annual Report, xv, pages 246, 387. 



Meg. Similar to No. 868F, but more markedly schistose. 

 Mic. The section resembles that of No. 868F, but contains more chlorite. 

 One section. 



Age. Keewatin. u. s. G. 



No. 868H. CHLORITE SCHIST. 



Same locality as No. 868E. 



Ref. Annual Report, xv, pages 246, 387. 



Meg. Similar to No. 868F. 



Mic. The section is similar to that of No. 868F, but in places contains large 

 quartz grains. One section. 



Age. Keewatin. u. s. G. 



No. 8681. JASPILYTE (?) 



Same exposed surface with No. 868E. 

 Ref. Annual Report, xv, pages 246, 387. 



Meg. A very fine-grained, slaty, black rock. 



Mic. The section is very fine grained and is made up of quartz and a black, 

 opaque substance. This latter is finely divided and is very abundant. It may be 

 carbonaceous material. The rock powder yields no particles to the magnet. 



One section. 



Age. Archean. 



Eemark. Nos. 868 to 868B and 868E to 868H, appear to be different facies of 

 the same rock mass, but No. 8681 is entirely'different. u. s. G. 



