GEOLOGICAL EXPLOKATIONS AND LITERATURE. 



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The (icfiu'renee of inangaiiese t-aii not from ]>ies<'iit f\|iloit:iti()iis Im- considered 

 as being at all regular, but its appearance in what i.s called the south \ein is more 

 general than in the ore of the so-called north vein. The ])roportions (»f this metal 

 vary ft-oni a trace to 3."? per cent iu quantities of ore, and specimens of jtyrolusite are 

 found. Alumina is found in most of the ores, the amount \arying from ()-.5 to 5 ]ier 

 eent, while the suli)hur is from O-oa to -l.'^ ]»er cent. Water to the extent of 5 per 

 cent exists iu the hard ores and to a gi'eater amount iu the .softei' varieties. Traces 

 of sulphiu', magnesia, and lime are also determined by analysis. 



The Colby mine produces an ore which carries more manganese than most of 

 tho.se on the Gogebic range, the average composition of the ore as shipped being as 

 follows : 



Averayt conipusitioii of shipmeiils of iioii ure from tht Culbij mine, Goyebic laiiye. 



Iron 



Manganese . 

 Phosphorus 



Per cent. 



5«. 5 

 3.5 

 .04 



Some of the ore taken from what was termed the .south vein carried as much as 

 33 per cent of mangauese. Other amilyses of the ore from this mine show the 

 following : 



Additloiuil aiiulij<it8 uf iron ore from the L'ulbij mine, Goijebiv raiiye. 



Iron 



Silica 



Phosphorus 

 Ahimina . . . 

 Manganese . 



No. 1. No. 2. 



Per cent. 



58.67 



5.87 



.049 



1.05 



3.49 



Per cent. 



59.59 



6.13 



.05 



.51 



8.45 



Mr. Birkinbine naturally at thi.s time shared in the current opinion 

 that there was in this region two well detined horizons at which the ore 

 occuri'ed in lenses. Suffice it here to say that, as ex))lained at length later, 

 the ore-bodies do not occur iu lenticular l)ut in peculiar sha})ed bodies 

 which have been ascertained to have remarkable relations with the luider- 

 lying quartzite and the associated soapstones. The onl}' mention made in 

 this report of the association of the ore and soap rock is an occurrence in 

 the Ashland mine. Mr. Birkinbine notices that the manganese is upon the 



