Plate XXV.— JASPILITE FKOM JASPER BLUFF, ISHPEMING. 



This is a representation of a typical piece of the brilliaut .jasiiilite ■whicli occurs associated with the 

 hard ores of the Marquette district. The rock was folded in the zone of combined fracture 

 and tlovrajie. The jasper bands bent for a certain time without mafroscopic fracture, but later 

 were broken through aud through. During the time of folding the rock may have been more 

 deeply buried than during the time of fracturing. At both periods the hematite accommodated 

 itself to its new position without apparent fracture. However, the lamime moved over one 

 another, giving them a brilliaut specular appearance. To some extent it flowed in between 

 tlie broken jasper fragments. Between the leaflets of hematite there were minute spaces. The 

 spaces, large and small, were occupied by subsequently intiltrated hematite and magnetite, which 

 in thin section may be discriminated by its crystal outlines from the hematite present before 

 the folding. 

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