20 ' THE PENOKEE lEOl^-BEARING SERIES. 



rocks (4) includus tlie grauitif, gueissic, and schistose rocks which lie to 

 the south of the Peiiokee range and form, as he says and as we also Ijelieve, 

 the oldest division of the region. We are not sure that we fully under- 

 stand Whittlesey's statements at the close of tlie quotation above, as to the 

 relative ages of the dift'erent rocks of tlie region. It seems that he would 

 say that the various cruj)tivc rocks of the Keweenaw series whicli occupy 

 tlie belt of country Ijetween the red sa^idstone on tlie north and the iron- 

 bearing slates 1)11 the south are all of them of an intrusive nature, having 

 been thrown to the surface after the formation of the red sandstone, which 

 they have thrust northward, at the same time pushing the .slaty series 

 to the south, llis j)osition as to the more recent origin of these trappeau 

 rocks relatively to the red sandstone is one which, of course, can not l)e 

 maintained. It has been abundantly proved l)y the work of the Wisconsin 

 Survey (1873-1879) that these eruptive rocks antedate the red sandstones. 

 In large measure they originated as surface Hows; and, moreover, certain 

 of them have yielded tlu' most of the fragmental material, coarse and fine, 

 of which the sandstones are l)uilt. 



The following quotations have more especial reference to the iron- 

 bearing formation: 



There is a contiimons iiiouiitciin cliiiin from the Montreal river to Bladder lake, 

 the prolongation of the Porcupine inouiitaiu range in Michigan. I have called it the 

 Penokie range, this being the Indian word for iron, which is found in its westerly 

 portion in great force (p. tot). 



The most easterly ap])earauce of magnetic iron which I observed was in fissile 

 black slate, about -i miles west of the Montreal trail, along which the section Xo. 

 4 W. is made. The bed lies back of the trappose range, about 16 miles from the 

 lake, in a pnitrusiou of nictaiiioridiic slates, the argillaceous jiortions merely tinged 

 with iron. About 4 miles along the strike of the beds, southwest by west, the bed 

 was seen by Mr. Randall in 1S48, in the fourth principal meridian, in township ii 

 north, 18 miles from the lake. From thence I and my assistant, Mr. Beesly, an active 

 woodsman and faithful and acute observer, traced it at moderate intervals along the 

 uplift to the west end of "Lac des Anglais," or about 15 miles, to where the rang(! 

 terminates. Here the metaniorphic slates that Urst show themselves between the 

 Montreal river and the Montreal trail on the east sink beneath the level of the 

 country and arc replaced by syenitic rocks. 



By examining the sections >."os. 1,2, 3, and 1 W., attached to this report, the 

 position of the iron-bearing rocks will be found to be the same in each, and the 



