124 Van Hise — Attempt to harmonize some apparently 



the Marquette, Vermilion Lake and other Lake Superior iron- 

 bearing series. Here, as at Yermilion Lake and Hunter's 

 Island the overlying conglomerate containing the jasper frag- 

 ments has been derived from this underlying formation. We 

 thus can separate the Yermilion, Hunter's Island and Kaminis- 

 tiquia iron-bearing and associated rocks into two series, an 

 upper and a lower, just as we have been able to divide the 

 Marquette series into two divisions. 



Position of the OgishTci Manissi conglomerate. — If the 

 foregoing is true, it determines the place of the Ogishki 

 Manissi conglomerate. This has been placed by Dr. Alexander 

 Winchell* as a part of the Yermilion Lake Iron- Bearing, that 

 is, Lower Series. Professor X. H. Winchell,t having practi- 

 cally the same facts at his disposal has placed this conglomer- 

 ate as probably belonging with the Animikie, and the asso- 

 ciated slates have been given the same color as the Animikie 

 formation on his map. J 



If, as argued above, the debris of the conglomerates is de- 

 rived from the iron-bearing series after they have undergone 

 profound changes, they do not belong with those series, but 

 should be placed at an independent horizon or at the base of 

 the Animikie. These conglomerates have been regarded by 

 Mr. AY X. Merriam, who has done a very large amount of 

 work in northeastern Minnesota, as a layer overlying the 

 older formations. While the iron-bearing schists at Yermilion 

 Lake are in a vertical attitude, the clastic layers of which the 

 conglomerates are a part have been found on some of the 

 islands of Yermilion Lake by Mr. Merriam to be gently folded 

 into a series of rolls, although often having a vertical cleavage. 

 We thus conclude, as has been thought by Irving, that at Yer- 



knobs of the Marquette region vary by imperceptible stages into the schists asso- 

 ciated with the iron ore and jasper. (The Iron Ores of the Penokee-Gogebic 

 Series of Michigan and Wisconsin. C. R, Van Hise : this Journal, III, xxxvii, 

 H2-48, 1889; the Greenstone Schist Areas of the Meuominee and Marquette 

 Regions of Michigan. George H. Williams: Bull. U. S. Geol Survey Xo. 62.) 

 The schists are then, in part at least, of eruptive origin. That these well 

 laminated rocks should oot at first be regarded as eruptive is natural, but the 

 variation of massive igneous rocks into those which are well laminated as a re- 

 sult of dynamic action and metasomatic changes is now so well known that new 

 cases of it excite no surprise. I would by no means assert that all of the schist- 

 tose rocks associated with the iron-ores and jaspers in the Marquette and Ver- 

 milion districts to be of eruptive origin, but this is certainly the case at many 

 localities. This view reverses Dr Wadsworth's and makes his sedimentary rocks 

 eruptive and his eruptive ones sedimentary. It will, however, be seen that this 

 position harmonizes Irving's conclusion as to the sedimentary origin of the ores 

 and jaspers, and the point upon which Dr. Wadsworth places most emphasis, that 

 there are irruptive contacts between these rocks and the associated schists. 



*Geol. and Xat. Hist, Survey of Minnesota. 16th Ann. Rept., 1S8T, p. 359; 

 Proc. Am. Assoc Adv. Sci.. 38th Meeting, pp. 234. 235. 



fGeol. and Xat. Hist. Survey of Minnesota. 16th Ann. Rept., 1887, p. 98. 



% Geol. and Xat. Hist. Survey of Minnesota, loth Ann. Rept., 1886, pp. 

 208-209. 



