PETROGRAPHIC GEOLOGY AND DESCRIPTIONS. 323 



Mica schist. Granite. Gneiss.] * 



number of grains whose characters could not be determined positively. It thus 

 seems that quartz is very rare, if not entirely lacking, in this section. 



One section. 



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



No. 335. MICA SCHIST. 



"Biotite mica schist, separated from No. 334 by a recurrence of rock like No. 332, conformable in dip with 

 the last. This includes irregularly shaped masses or agglomerations of Nos. 336 and 337; also has thin, irregular, 

 interrupted and contorted interlaminations of the same. They are certainly interstratified." Same locality as 

 No. 332. 



Ref. Annual Report, ix, pages 88, 89. 



Meg. There are two hand samples. The first is a gray mica schist of fine 

 grain. The second is a darker, greener rock, and seems to be a hornblende schist. 



Mic. The section, which is remarkably thick, was evidently made from the 

 first hand sample. It shows biotite and quartz (with possibly feldspar) in fine grains. 

 The biotite is in flakes lying approximately parallel, an'd to this is due the schistose 

 structure of the rock. 



One section. 



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



No. 336. GRANITE (with hornblende). 



"Biotite(?) hornblende gneiss, of a light-gray color, alternating along the beach two or three times, con- 

 formably with No. 335." Same locality as No. 332, but along the beach further south. 

 Ref. Annual Report, ix, pages 88, 89. 



Meg. Fine-grained, gray granite, composed of gray feldspar, quartz and horn- 

 blende. 



Mic. The section is closely similar to No. 332. 



One section. 



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



No. 337. GRANITE (with hornblende). 



Same locality as No. 332, near No. 336. 



Ref. Annual Report, ix, page 89; Annual Report, x, page 95. 



Meg. A rather fine-grained, gray granite, composed of gray feldspar, hornblende, 

 (with probably some biotite) and quartz. No section. 



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



No. 338. GNEISS (luith hornblende). 



Same locality as No. 332, still further south, near the beach and island. 

 Ref. Annual Report, ix, page 89. 



Meg. A rather fine-grained, dark-gray granitic rock having a somewhat 

 schistose structure due to the arrangement of the hornblende. Composed of horn- 

 blende, gray feldspar and apparently quartz. 



