GEOLOGICAL EXPLORATIONS AND LITEliATURE. 23 



river, at Peuokee gap, eastwjird to the fourth principal meridian, and west- 

 ward to tlie end of the range soutli of English lake. The map accAmpan}'- 

 ing the paper is topographical only and is very simple, having been com- 

 piled from the U. S. I^and Office township jdats ; the only addition on it to 

 information afforded by these plats being the course of the crest of the 

 nuige. It is to be noted that Lapham's j)ublication is the first giving any 

 geological facts based on an examination of the region sul)sequent to the 

 completion in it of the Land Office Survey. 



The following quotation includes nil of geological Interest given in 

 tins paper : 



Tliis ri'iiiarkahlt' iiionutaiu range lias l)een traced from a little east of tlie fourth 

 priucipal meridian in township 45, in a direction a little south of west, across three 

 ranges of townships; its length being about 20 miles, as shown on the accompanying 

 map. At the west the range appears to slope down and terminates, but toward the 

 east its extent is not known. The highest summits are about 1,-00 feet above lake 

 Superior, or 1,.S()0 feet above the sea; the meau height is 100 or -*00 feet less. Tyler's 

 fork crosses the range at a place called '"The Gorge,-' and Bad river crosses at Peuo- 

 kee, through a gap cut down to a depth of about .300 feet; the river here having an 

 elevation above lake Superior of 608 feet. 



On the north side the slope of the range is moderate, and covered with "drift;" 

 but on the south it is quite abrupt, and steep, rocky precipices occur, looking as if 

 they had at s<jme remote period of the past formed the shores of some great body of 

 water. 



What gives this great ridge its ])eculiar interest and importance is the innnense 

 stratum or bed of magnetic iron ore which it contains, extending, with varying thick- 

 ness aiul value, throughout its whole length. It is not, therefore, an Iron mountain 

 simply, like those heretofore known in Missouri and elsewhere, T)ut, as its name imiiorts, 

 an Iron range; as if mountain masses of iron had been passed between gigantic rollers 

 and drawn out for a length of 20 miles. The ore is found in a very ancient chloritic 

 slate, so ancient that it is supposed to have been deposited long before the existeniie 

 of vegeta])le oi- aninnil life upon the globe. The slate rests ajton a light colored 

 quartz-rock, winch usually extends to the base of the range on the soutli side. The 

 ore is laminated, like the slate, and apparently has had the same origin; for, as we 

 asceud from the (juartzi'ock the slate becomes more and more ferruginous until it 

 passes into pure iron ore. This change is so gradual that it is often difficult to deter- 

 mine where the slate ceases and the ore begins, <n' how much should be classed as 

 iron ore and how much as ferruginous slate. We noticed places where the ore had a 

 thickness of GO feet, at other places 10, and wherever we could get access to the rock 

 at the proper place the ore was found. 



