440 THE MARQUETTE IROX-BEARING DISTRICT. 



E. 80 W., and in sec. 18, T. 46 X., R. 3(» W. (Atlas Sheets VII and X.) 

 To describe in detail each of these localities would vetjuire too much space. 

 They are therefore treated together. 



At the various mines the basal horizon is a coarse magnetic ore, asso- 

 ciated with considerable chlorite, and iu some places with pp-ite. As this 

 ore becomes lean it contains quartzose bands, which show large clear grains 

 or pebbles of c|uartz that appear to be fi-agmental. These white quartz 

 bands never verj closely simulate the red or white jasper of the Xegaunee 

 formation, and there is usually no sharp difterentiation between the ferru- 

 ginous and nonfeiTuginous bauds, as is the case with the jasper. They 

 are therefore discriminated in hand specimen from the true jasj^ilite of the 

 Xegaunee formation. If there were conglomerates deposited at the base of 

 the formation, at most places these have been wholly destroyed by the 

 dynamic action. In some cases the bands of quartz have a lenticular 

 appearance, as if they were greatly flattened quartz pebbles. 



At two places, where erosion has cut away the Lower Marquette series, 

 the rocks of the Ishpeming formation are found close to the granite. The 

 first of these localities is southeast of the Erie mine, in the XE. J sec. 28, 

 and the latter northwest of the same mine, in the SE. 5 sec. 20. At the 

 first of these localities the rock is a coarse-grained, foliated, micaceous 

 quartz-schist, which at one place contains distinct quartz pebbles. At the 

 second locality the rock is of a similar appearance, and it contains distinct 

 pebbles of white quartz and of jasper. This rock is associated with a 

 massive, greenish-gray, homblendic quartzite. These coarse rocks jiass uj) 

 into fine-grained, micaceous quartz-schists. 



The hea^aly ferriferous rocks of the mines are closely associated with 

 or grade Into muscovitic quartz-schists; these grade into completely crys- 

 talline, thoroughly foliated mica -schists, like those of the Michigamme 

 formation. 



Associated with tlie mica-schists, gTiineritic and magnetitic schists are 

 found. These may be particularly well observed west of the Kloman 

 mine, adjacent tf> and south of the road. This gi-iinerite-magnetite-schist 

 contrasts with that of the Xegaunee formation in having a rough appear- 

 ance upon the weathered surface, and in having a peculiar toughness which 



