CHAPTER VII. 

 GENERAL GEOLOGY. 



By C. E. Va>- Hise. 



lu considering the general geology of the Mai'quette district we have 

 to deal with three series : The Basement Complex, the Lower Mai-qnette, 

 and the f pper 3L\rquette. These thi-ee series are sepai-ated br uncon- 

 formities. The Basement Complex includes gi*anites, syenites, gneisses, 

 manv linely crystalline schists, smiace volcanics, and vaiious subsequent 

 intrusives. The complex south of the Marquette series is spoken of as 

 the Southern Complex; that to the north as the Northern Complex. The 

 Lower Marquette series, from the base iqtward, comprises the Mesuard 

 quartzite, 110 to 670 feet thick; the Kona dolomite, 425 to 1,375 feet 

 thick: the Wewe slate, 550 to 1,050 feet thick; the Ajibik quartzite. 700 to 

 900 feet thick: the Siamo slate, 200 to 625 feet thick; and the Negaimee 

 u-on formation, 1.000 to 1.500 feet thick. "We thus have a minimum thick- 

 ness for the series of 2.975 feet, aud a possible maximum of 6.120 feet. 

 It is not probable that anv single section will give so great a thickness as 

 5.000 feet. The L'pper Marquette series comprises the Ishpemiug formation, 

 which includes the Goodi'ich quartzite aud the Bijiki schist, the Michigamme 

 formation, and the Clarksbiu-g formation. It is impossible to give even 

 an approximate estimate of the thickness of the L^pper Marquette series, 

 but in the disti-ict considered, excluding tlie volcanics. it is probably less 

 than 5,000 feet. Including the volcanic Clarksbui'g fonnation the series 

 is probably over 5,000 feet thick. 



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