606 THE GEOLOGY OF MINNESOTA. 



[Gneiss. Granite. 



No. 933. GNEISS. ( Hornblendic. ) 



Sec. 14, T. 63-18 W.; north shore of West bay, Vermilion lake. 

 Ref. Annual Report, xv, pages 296, 390. 



Meg. A rough, schistose, green rock, composed largely of hornblende with some 

 feldspar. There are a few narrow bands, parallel to the schistosity, of feldspathic 

 material. The rock may be called a banded gneiss. 



Mic. The section was evidently made from the green part of the rock. It 

 consists essentially of green hornblende and feldspar, which is much kaolinized and 

 sometimes shows albite twinning lamellae. 



One section. 



Age. Archean. u. s. G. 



No. 934. GRANITE. 



" Intrusive granite, obtained at the mouth of Rice river, so called, N. E. % sec. 15, T. 63-18." North shore 

 of Vermilion lake. 



Ref. Annual Report, xv, page 390. 



Meg. Coarse-grained, reddish granite. The minerals are feldspar, quartz and 

 a dark mineral, in small amount, which is sometimes hornblende or chlorite and 

 sometimes biotite. One of the specimens shows a small band of this rock cutting 

 dark hornblende schist. 



Mic. A coarse granite, composed mainly of feldspar and quartz, with a little 

 chlorite. The feldspar is more or less kaolinized and appears to be acid plagioclase 

 perthite and orthoclase. One section. 



Age. Archean. u. s. G. 



No. 935. GRANITE. (Biotitic.) 



Small island in Partridge lake near the east line of sec. 11, T. 63-18 W., or perhaps from a reef in Vermilion 

 lake in N. W. J4 sec. 26, T. 63-18 W. There is uncertainty as to which of these localities is the correct one. 

 Ref. Annual Report, xv, pages 297, 390. 



Meg. The specimen is a medium -grained, gray, biotite granite. On one side is a 

 layer, probably a vein, of quartz and a little pink feldspar. 



Mic. The section shows a granite, composed essentially of feldspar, quartz and 

 biotite. The feldspar is apparently orthoclase and acid plagiodase. Considerable 

 chlorite is present, and cpidote, sphene, Muscovite and iron ore also occur. 



One section. 



Age. Archean. u. s. G. 



No. 936. GRANITE. (Biatitir. ) 



From a small island at the northwest corner of sec. 32, T. 63-17 W., Vermilion lake. 

 Ref. Annual Report, xv, pages 294, 390. 



Meg. A medium-grained, light-gray granite, composed of feldspar, quartz and 

 a comparatively small amount of biotite. 



