636 



THE GEOLOGY OF MINNESOTA. 



[Granite. Gneiss. Biotite schist. 



No. 1031. GRANITE. 



Same place as the last, at fifteen feet from the contact on No. 1028. 

 Ref. Annual Report, xv, pages 358, 394. 



A medium-grained, dark-gray, granitic rock. 

 Mic. Similar to the last, but with more hornblende and biotite. Large feldspars 

 (microcline) englobe many small hornblendes, as well as smaller feldspars, and 

 ti/Hitite. One section. 



Age. Archean (granite). N. n. w. 



No. 1032. GRANITE. 



Sec. 23, T. 65-10; northeast cape, Bassimenan lake. 

 Ref. Annual Report, xv, pages 358, 394. 



Meg. lied weathering, gneissic and jointed, gray within. 



Mic. Quartz, orthoclase, microcline, the feldspars clouded by decay; hornblende, 

 biotite, apatite. One section. 



Aijv. Archean (granite). N. H. w. 



No. 1033. GNEISS. 



Prom bands cutting the rock No. 1032 in a direction about east and west. 

 Ref. Annual Report, xv, pages 358, 394. 



Me//. Dark gneiss. 



Mic. Ortltoclase, hornblende, quartz, the first frequently blurred by alteration, 

 and a few grains of plngioclase, with many minute crystals of iif/at/le. One section. 



Age. Archean (gneiss). 



N. H. w. 



No. 1034. GRANITE. 



Vein rock, sec 23, T. 65-10. 



Ref. Annual Report, xv, pages 358, 394. 



Meg. Coarse grained, and apparently containing the 

 same minerals as No. 1032, in form of a segregation in 

 coarse veinings in No. 1032. 



Mic. Quartz, orthoclase, microperthite, plagior/ase and 

 micropegmatyte. 



Figure 36 represents the microperthite, apparently 

 running parallel with the cleavage 001. Compare the 

 description of No. 1051. One section. 



Age. Archean. N. H. w. 



No. 103"). BIOTITE SCHIST. 



East end of the portage from Ensign to Illusion lake, sec. 13, T. 64-8. 

 Ref. Annual Report, xv, pages 359, 394. 



Meg. Fine grained, dark gray, in some places apparently schistose. 



MitfOftrtkitt in 1034. 



FIG. as. 



