GEOLOGKJAL EXPLOllATION.S AND LITEIIATUKE. 21 



details of the ictcky beds ;ibt)ve and below tlic iron are also the ^aiiie, so tliat we may 

 with confidence prouounce it to be a <'ontinnons bed from the ini'iidian westward to 

 Lac des Anijlais. Its thickness, liehness, and value vary very iiineli, bnt we Ibniid it 

 more or less developed whenever we crossed the range and eouhl get a view of 

 the rock. 



The geological relations of the iron-bearing strata are exhibited in the two fol- 

 lowing sections, the first taken near the trail that passes over the Pewabic range 

 between the forks of the Tyler branch of Bad river, the second south of Lac des 

 Anglais. 



On the Pewabic range the strike of the beds is east by north; the dip north by 

 west 80° to 8.50. The beds of quartz are of great thickness — 2(t() to 250 feet. Near 

 the junction of the quartz and talcose slate the latter assumes the aspect of novacu- 

 lite. The iron bed is schistose iu its structure and is (■oiui)osed of magnetic oxide, 

 sometimes alternating with beds of quartz. The total thittkness of the talcose slate 

 is not seen; it uuist be very, thick and is traversed by numerous veins of quartz. Its 

 dip and strike are variable. 



The bed of magnetic iron ore south of Lac d<'s Anglais is of extraordinary thick- 

 ness — 25 to 60 feet. The dip here is northeasterly, and the layers variable in thickness 

 that alternate with quartz, which latter repose upon liornblen<lic slate, running down- 

 ward into talcose slate. Here, as well as on the Pewaliie range, the dip and strike 

 of the beds are variable. 



The metamorphic strata are very much disturl)ed throughout this range, but 

 agree in having the mural faces of the uplifts to the south and southeast, and the dip 

 northerly and northwesterly at various angles of tVom 5^ to (iO^. The effect of this 

 irregular action is to make detached ridges and crests, sometimes 2, 3, and 5 miles 

 long, thrown up at dift'erent elevations and inclinations. 



Sometimes the iron stratum is coiuiyosed of lamina' of quartz and magnetic 

 oxide, alternating, as at the crossing of the tiail between the forks of the Tyler branch 

 of Bad river; also south of Lac des Anglais. 



The proportion of iron and quartz is very variable, but the sejiaratiou of them by 

 mechanical means would in general not be diilicult. The bands of ore vary from mere 

 thin laiuiuiv to a thickness of 12 and even LS inches, iiresenting sometimes a black 

 surface, contrasting with the white and gray color of the (piartz, and sometimes a 

 bright metallic gray color. The thickness of the metalliferous poition varies iu the 

 extreme from 5 and 10 feet up to 50 and 70 feet, and at the jiassage of the main 

 portion of Bad liver through the range reaches 250 feet. Tliese exposed faces fre- 

 quently extend beneath the surface, where, of course, no estimate can be formed of 

 their entire thickness. 



• There are many places in the mountain, west of Bad river, which present more 

 than 50 feet of quartz and iron, in about eiiual ])ro|)ortions. In the wild and deep 

 ravines where the Bad river breaks through the range there is a cliff of slatj' ore. 



