862 THE GEOLOGY OP MINNESOTA. 



[Dioryte. Granite. 



No. 2216. DIORYTE. 



Near the same place as the last, but from the north side of the little bay. 

 Ref. Annual Report, xxiv, page 67. 



Meg. A rock of finer grain than the last, of a dark gray color. 



Mic. Seems to consist wholly of hornblende and a much altered plagiodase, the 

 latter being embraced ophitically by the former, and hence was originally a diabase. 

 The plagioclase is so much altered that it has almost entirely lost its striations. 

 One section. 



Age. Archean. N. H. w. 



No. 2217. DIORYTE (with quartz.) 



Prom the south side of the same little bay. 

 Ref. Annual Report, xxiv, page 67. 



Meg. Resembles rock No. 2215, but finer grained. 



Mic. Considerable areas of quartz are found amongst the other minerals so 

 as to embrace them even the altered hornblendes. The feldspar is only partly 

 plagioclase; the rest is more decayed and is taken for orthoclase. Biotite and chlorite 

 are quite common. One section. 



Age. Archean. 



Remark. This rock seems to be only a phase of the granite. N. H. w. 



No. 2220. GRANITE (.with Itornblende). 



A short distance further west. 

 Ref. Annual Report, xxiv, page 67. 



Meg. Darker than Nos. 2218 and 2219, but lighter than Nos. 2215 to 2217. Some 

 feldspars are red. 



Mic. With much hornblende are both plagioclase and orthoclase, the latter 

 considerably kaolinized; also a little biotite and magnetite. One section. 



Age. Archean. N. H. w. 



No. 2221. GRANITE. (Hornblendic.) 



Narrows of the Kawishiwi river, N. E. % S. E. J sec. 5, T. 62-10, a little west of the so-called palisades. 

 Forms a small knob on the north shore. 



Ref. Annual Report, xxiv, page 68. 



Mey. Compact, dark, hornblendic gneiss, with epidote in one of the open seams, 

 cut by veins of red granite. 



Mic. The section shows a fresh hornblendic granite, with considerable quartz. 

 The more altered feldspar* may be assumed to be orthoclase, and the rest, which are 

 twinned polysynthetically, are some species of plagioclase. Epidotc accompanies and 

 surrounds small masses of magnetite. It is in multiple granules, and in that form is 

 also scattered through the rock. One section. 



Age. Archean. 



