PETROGRAPHIC GEOLOGY AND DESCRIPTIONS. 699 



Muscovadyte. Labradoryte.] 

 Biotite gneiss. Slate. 



The same indefinite greenstone as No. 1335, forming a continuous promi- 

 nent east and west range, underlying the ferruginous quartzyte above. 



Mir. Plagioclase, hornblende, a little biotite and a little globular augite make up 

 this rock. These all (except the hornblende) are in roundish or globular form and 

 are frequently included in the large hornblendes. The plagioclase is labradorite. 

 One section. 



Age. Keewatin (regenerated basic clastic). N. H. w. 



No. 1347. MUSCOVADYTE. 



North shore of Muscovado lake, sec. 36, T. 65-5. 



Ref. Annual Report, xvi, pages 88, 89, 122 ; Annual Report, xix, pages 199-201. (Compare No. 2197.) 



Meg. Granular gabbro. 



Mic. The rock is characterized by a uniformly granular and globular condition 

 of all the minerals, which are those characteristic of granulitic gabbro. The 

 feldspars sometimes contain small rounded aiic/ites and magnetites poikilitically, and 

 the augites hold the magnetites in the same way. One (thick) section. 



Age. Cabotian (regenerated fragmental Keewatin). N. H. w. 



No. 1348. LABRADORYTE. (Anorthosytc.J 



North part of sec. 11, T. 64-5, south side of Bashitanequeb lake. Forms an elevated bluff. 

 Ref. Annual Report, xvi, pages 89, 122. 



Meg. Like the well-known "feldspar rock." 



Mic. The rock consists almost entirely of labradorite, whose extinction angle 

 on 010 is 22; but there is a little magnetite, about which, on its borders, is a little 

 brown biotite. There are also a few small, straggling shreds of augite. Several 

 larger grains of augite are alternately twinned with bronzite( ?) in narrow bands. 

 One section. 



Age. Cabotian. N. H. w. 



No. 1350. BIOTITE GNEISS. 



North side of the point, sec. 32, T. 65-5, Gabemichigama lake. 



Ref. Annual Report, xvi, pages 89, 122 ; Annual Report, xxi, page 148. 



Meg. Apparently finely fragmental, a condition of the rock which lies below 

 the gabbro. (See Nos. 1089-1092 and 1777.) 



Mic. Granular, consisting of plagioclase, diopside, biotite, quartz, magnetite. 

 One (thick) section. 



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



No. 1351. SLATE. 



S. W. % sec. 29, T. 65-5. North of Gabemichigama lake. 

 Ref. Annual Report, xvi, pages 89, 122. 



Meg. Fine, fragmental, sedimentary, highly tilted (45) toward the northeast. 



