88 THE VERMILION IRON-BEARING DISTRICT. 



The Ogishke conglomerate is not to be confounded with the Stuntz 

 conglomerate, which occupies a lower stratigraphic position than does the 

 Ogishke. That the Kewatin schists are eruptive is regarded as improbable. 



4. The Animikie series, resting unconformably upon the Keewatin, 

 stretches from Thunder Bay as far as Duluth and still beyond to the 

 Mississippi, and perhaps includes some of the slates as far west and north 

 as Knife Lake. The Animikie formation is generally in a nearly horizontal 

 position, the dip not being more than from 5° to 15° SSE. The formation 

 is essentially an argillite, which embraces jaspery magnetitic, hematitic, 

 and sideritic beds. At Gabimichigama Lake the Animikie, represented 

 by the "muscovado," is in its characteristic horizontal position, while the 

 vertically bedded terrane underlies it. The sedimentary series is cut by 

 dikes of igneous rock, determined macroscopically as diabase-norite and 

 porphyry. 



For the system of semicrystalline schists subjacent to the Animikie, to 

 which the term Kewatin has been applied, Marquettian ' is proposed. The 

 succession of terranes in northeastern Minnesota is, in descending order, 

 summarized as follows (pp. 366-367): 



HuRONiAN SYSTEM (compare sec. 2 of this report"), over 4,082 feet. 

 Magnetitic group. 32 feet. 



Dark, laminated, shaly argillite, sometimes magnetitic, 29 feet. 



Magnetitic heds, often uppermost, 8 feet. Place of sideritic bed? 



Muscovado, uppermost when the two above are wanting, -i feet. 

 Siliceous group. 60 feet. 



Siliceous argillites and siliceous and jaspery schists, 50 feet. 

 Argillitic group. 4,000 feet. 



Dark, laminated, shaly argillites, over 4,000 feet in Minnesota. 



(Bottom of the S3'stem not reached at contacts seen with gneiss and 

 Marquettian.) 

 Marquettian system. 27,600 feet. 



Ogishke gi-oup. 10,000 feet, but local. (Perhaps half this). 



Ogishke conglomerate, slatj' and diabasic. 4,600 feet each side of synclinal. 



Ogishke dolomite, included in the conglomerate, 10 feet. 



Conglomerate greenrock. 500 feet each side of synclinal. 

 Tower group. (Earthy schists.) 15,000 feet. 



Sericitic and argillitic schists, with beds of hematite, 5,000 feet. 



(These sometimes changed to chloritic schists.) 



■'This refers to Sixteenth Ann. Rept. Minn. Geol. and Nat. Hist. Survey. 



