412 THE MAEQUETTE IliOXBEAlUNG DISTEICT. 



materials constituting this complex are predominant in the conglomerate. 

 At various places — as, for instance, in the great conglomerate at and 

 immediately south of the village of Palmer — there are abundant quartzitic, 

 gi-anitic, and schistose bowlders, derived from the Archean, and also 

 abundant jaspilite detritus from the Negaunee formation. 



The basal conglomerate, of varying thickness, grades up into quartz- 

 ites, which are apt to contain much of chert and jasper in minute 

 fragments. The higher horizons of the quartzite are usually feldspathic. 

 Frequently the mashing due to the folding was so severe as to partly or 

 wholly destroy the fragments of ore and jasper, making the rock a schist- 

 conglomerate or schistose quartzite. Tliis change is complete at the places 

 where the close infolding which has been spoken of occurs, as at the Jack- 

 son mine, at Humboldt, and in the Republic trough. In the most extreme 

 stage of alteration it is difficult to discriminate the mashed recomposed oi'e 

 and jasper conglomerates from the original jaspihte. In passing from the 

 least altered to the most altered phases we find, first, flattened pebbles, then 

 those which nre elongated into layers, and finally those in which are alter- 

 nating layers of different thickness, which simulate original lamination in 

 a remarkable degree. 



In the case of the nonconglomeratic recomposed jaspers the rocks are 

 not unlike the original formation, although a close examination usually 

 shows a difference. Ordinarily, large fragmental grains of quartz are seen; 

 flakes of mica are often present ; and the banding is less distinct than in the 

 original jasper. 



Under the subject "Negaunee Iron Formation" the development of ore 

 bodies within the Goodi-ich quartzite has been mentioned. The ore usually 

 occurs at places where the detritus was rather fine grained, and thus con- 

 tained no large fragments of chert and jasper. As conspicuous localities 

 for the occurrence of these recomposed ore bodies may be mentioned 

 the Volunteer mine, the Barron, the Humboldt, the Champion, part of the 

 Jackson, and part of the Michigamme and Spurr. As a consequence of 

 the intense mashing which the formation underwent, numerous cracks 

 developed and minute spaces formed between the laminae and between the 

 individual jjarticles. Where the rock was enriched so as to become an ore, 



