608 THE GEOLOGY OF MINNESOTA. 



[Granite. 



Meg. A coarse-grained, granitic rock composed of quartz, feldspar (white and 

 pink iii color) and biotite. 



Mic. Quartz, feldspar and biotite are the chief minerals of the section. The 

 feldspar is considerably clouded, and appears to be ortlioclase and acid playiodase. 

 The biotite is altering to chlorite. One section. 



Ay<>. Archean. u. s. G. 



No. 941. GRANITE. 



Same place as No. 940. 



Ref. Annual Report, xv, pages 301, 390. 



Meg. Pinkish, medium-grained granite, composed of quartz, feldspar and a 

 very small amount of a dark micaceous mineral. On one side of the specimen is a 

 contact with a much finer-grained, reddish granite. 



Mic. The slide shows principally feldspar 1 and quartz. The former is commonly 

 much clouded and appears to be ortlioclase, acid playiodase and perthite. A little 

 chlorite is present. One section. 



Age. Archean. u. s. G. 



No. 942. GRANITE. 



N. W. y sec. 25, T. 63-16 W., Vermilion lake. 

 Ref. Annual Report, xv, pages 301, 390. 



Meg. A rather fine-grained granite, composed of feldspar and quartz, with very 

 little of a dark mineral. 



Mic. The section shpws a granite, composed largely of quartz and feldspar, 

 which seems to be orthoclase and oligoclase, with a small amount of microcline. A . 

 little chlorite, probably an alteration product of biotite, is present. 



Age. Archean. u. s. G. 



No. 943. GRANITE. 



Locality uncertain, but north of Pine island; either the same as No. 940 or from N. E. J sec. 27, T. 63-16 

 W., Vermilion lake. 



Ref. Annual Report, xv, pages 301, 390. 



Meg. A rather fine-grained, pinkish granite. 



Mic. An ordinary granite, with the feldspar much clouded by alteration. The 

 dark mineral is not abundant and is chlorite. One section. u. s. G. 



No. 944. GRANITE. (Biotitfc.) 



Near centre of sec. 27, T. 63-16 W., Vermilion lake. 

 Ref. Annual Report, xv, pages 301, 390. 



Meg. A fine-grained, gray to pinkish granite. 



Mic. An ordinary biotite granite, with the feldspar much clouded by alteration 

 and the biotite altering to chlorite. Some muscovite is present. One section. 



Age. Archean. TJ. s. G. 



