434 THE MARQUETTE IRON-BEARmCr DISTRICT, 



coarseness to tlie granulated quartz, and between the grains much sericite 

 and chlorite has developed. Where the fragmental grains were large their 

 granulation resulted in distinct flattening. These granulated areas free 

 from the mica still indicate the fragmental character of the rock. At the 

 localities southeast of Humboldt, in sec. 18, where there are a number of 

 exposures of quartzite, the rock is sericitic, less crystalline than that near 

 Humboldt, and more nearly like the normal Goodrich quartzites. 



Champion area. — In tlic viciuity of Cliampion, at the various mining pits, 

 the lowest horizon of the Ishpeming formation is represented by the granu- 

 lar magnetic ore and the magnetitic hematite-schist of the mines (Atlas 

 Sheet XII). The impure phases of the ore contain jaspery quartz and 

 green chloi-ite. These grade up into hematitic and magnetitic quartzites 

 and quartz-schists. These latter are associated with or overlain by biotitic 

 graywackes, biotite- slates, or biotite- schists, many of which are garnet- 

 iferous, and in some cases are griineritic. Rai-ely the rock approaches in 

 appearance the gTiinerite-magnetite-schist as developed at Bijiki River, as, 

 for instance, southeast of Champion, north of the road, a short distance 

 east of the west quarter post of sec. 4 These schists in places are acutely 

 folded in a minor way. On the road just east of the Champion mine the 

 schist becomes conglomeratic. The matrix of the conglomerate is garnet- 

 iferous mica -schist. It holds very numerous pebbles and bowlders of 

 many varieties, including schistose granite, quartzite, quartz -schists, etc. 

 Some of the bowlder-like areas are several feet in diameter. The ques- 

 tion arose at the locality as to whether they could be parts of folded or 

 broken layers, rather than true bowlders, but this seemed hardly possible. 

 This rock is one of the most crystalline schist -conglomerates of the 

 Marquette district. 



In places the mica-schist is almost immediately north of the rocks of 

 the Negaunee formation. The presence of biotite in the mica-schist, the 

 different character of its banding, and an in-egular weathering, due to cer- 

 tain constituents dissolving out, thus giving the rock a ridgy appearance, 

 enable one to discriminate the Ishpeming rock from the Negaunee. In the 

 presence of the mica-schists and schist-conglomerates, and in the absence 

 of any considerable quantity of pui-e quailzite, the rocks of the Ishpeming 



