110 KEMP'S ORE DEPOSITS. 



2.02.25. Example 9d, Vermilion Lake, Minnesota. Beds of 

 hard specular with but little soft, intimately associated with jas- 

 per (or jaspilyte, as locally called), and both contained in green 

 schists. The district is situated in the northeastern corner of 

 Minnesota, and northwest of Lake Superior. Two Harbors, the 

 shipping point, is twenty-six miles east of Duluth. and Tower, 

 the chief mining town, is sixty-seven miles from the docks. Leav- 

 ing the lake, the railroad first crosses the north flank of the Lake 

 Superior synclinal, consisting of southerly dipping igneous rocks 

 belonging to the Keweenawan. Underlying these are a series of 

 gabbros and augite-syenites that contain titaniferous magnetite 

 and may be a parallel to the Adirondack norites. Next follow the 

 black slates of the Animikie, and then a heavy quartzite called the 

 Pewabic quartzite. N. H. Winchell applies to these collectively 

 the name Taconic, a term which the best work in the East rejects 

 in its home. They form the Mesabi range of hills. Sedimentary, 

 gneissic, and eruptive exposures, referred to the Laurentian, suc- 

 ceed in the north. Next come the Vermilion mica and hornblende 

 schistc, and after these the Keewatin sericitic schists, jaspilyte, 

 etc., containing the ore bodies at Tower. The Laurentian rocks 

 appear again on the north, arid beyond to the northwest is the 

 Rainy Lake region, studied by A. C. Lawson. All the formations 

 referred to above run in belts, having a general direction north and 

 east. The ore bodies which are important as yet are all in the 

 Keewatin. They vary in size from small bodies up to masses, 

 which extend as much as a mile on the strike. They approximate 

 the lenticular shape so characteristic of crystalline iron ore de- 

 posits. The jasper, or jaspilyte, is everywhere associated, often 

 very intimately, in parallel bands with the ore, while the contain- 

 ing rock is a green schist which is regarded as an altered igneous 

 rock or tuff. The principal mines are located at Tower, on Ver- 

 milion Lake, and at Ely, which is twenty-three miles farther north- 

 east. N. H. and H. V. Winchell, in the Bulletin referred to be- 



gion," Amer. Jour. Sci., iii., XXXII. 263, 265; see also under Van 

 C. D. Lawton, "Go^ebic Iron Mines,'' Engineering and Mining Journal, 

 Jan. 15, 1887, p. 42. C. R. Van Hise, "On the Origin of the Mica 

 Schists and Black Mica Slates of the Penokee-Gogebic Iron bearing Se- 

 ries," Amer. Jour. Sci,, iii., XXXI. 453-459. "The Iron Ores of the 

 Penokee-Gogebic Series in Michigan and Wisconsin," Amer. Jour. Sci., 

 iii., XXXVII. 32. C. E. Wright, Geol. Survey of Wisconsin, III., pp. 239- 

 301. 



