92 THE VERMILION lEON-BEAEING DISTRICT. 



formity (pp. 37-46). Above this lies the Animikie. This has the Ogishke 

 conglomerate as its base. 



This conglomerate is followed by an immense thickness of dark slaty rocks, 

 often cherty, or flinty, frequently very dark-colored, generally siliceous, alternating 

 with thin quartzites and grayish feldspathic quartzites, all in conformable stratifica- 

 tion, as a whole. Variously interbedded with these slates and quartzites, from 

 bottom to top, are beds of basic eruptive rock, . . . [pp. 47-48]. 



The Animikie series of Minnesota, bearing iron at one horizon, is the 

 equivalent of the Marquette series, the iron-bearing group of Rominger, of 

 the Penokee-Gogebic series of Michigan and Wisconsin, of the Mesabi 

 series in Minnesota, of the Black River iron-bearing schists in Wisconsin, 

 and of the quartzites of the Black Hills. All are of Taconic age, for the 

 Lower Cambrian is equal to the Taconic, the Huronian is equal to the 

 Taconic, therefore the Lower Cambrian is equal to the Huronian (pp. 46-48). 



In the Potsdam sandstone, which is uncomformably on the Taconic, 

 are included the upper quartzites of the original Huronian, certain of the 

 quartzites of Marquette, the Sioux quartzites of Dakota, and the quartzites 

 of Minnesota and Wisconsin. This is also the age of the copper-bearing 

 rocks, which are an alternation of basic and acid eruptions with interbedded 

 sandstones and conglomerates. The great gabbro eruption is later than the 

 beginning of the Potsdam age. Unconformably above the Potsdam is the 

 St. Croix sandstone (pp. 51-57). 



The general succession in descending order, is as follows (p. 68): 



Calciferous. Magnesian limestones and sandstones .. I __ __ _Dikelocephalus horizon 

 St. Croix. Sandstones and shales ] ' 



Overlap imcon formity. 

 Potsdam. Quartzite, gabbro, red granite, and Keweenawan. ..Paradoxides horizon 



Overlap imconforrtvity. 



Taconic. Black and gray slates and quartzites, iron ore (Huronian, 



Animike) Olenellus horizon 



Overlap unconformity. 



Kewatin. (Including the Kawishiwin or greenstone belt, with its jaspilite), 



sericitic schists and gray wackes - 



Vermilion. (Coutchiching) crystalline schists 



Eruptive unconformity. 

 Laurentian. Gneiss 



Archean 



