GEOLOGICAL EXPLORATIONS AND LITERATURE— 189L 129 



Hunt, T. Stekry. The iron ores of the United States. Trans. Am. Inst. 

 Min. Eng., Vol. XIX, New York, 1891, pages 3-17. 



In his Pittsburg- address to the mining engineers Hunt gave a rapid 

 re\aew of the geological relations of the iron ores of the United States. 

 The pre-Paleozoie rocks for the entire country are di\aded bv hini into 

 the Laurentian, Norian, Avoniau, Huronian, Montalban, and Taconic sys- 

 tems, and the rocks comprising them are Ijelieved to liave been deposited 

 in a hot ocean highly charged with active chemical agents. The Marquette 

 ores are placed in tlie last of the above divisions — the Taconic — and in 

 that division of it which tlie author denoniinates the Animikie. With 

 regard to the ores of these pre-Paleozoic terranes the aitthor writes: 



We moreover reject as untenable the notion of the igneous origin of the iron 

 ores themselves, which appear to be in all cases deposited from water, generally con- 

 temporaneous with the inclosing rocks, but more rarely by subsequent processes in 

 fissures, after the manner of mineral veins. (P. 5.) 



GOETZ, Geobgk W. Analyses of Lake Superior ores. Ibid., pages 59-61. 

 Goetz gives a record of the analyses of ores from thirty-six mines in 

 the Marquette district. 



Lane, A. C, Keller, H. F., and Sharpless, E. F. Notes on Michigan 

 minerals. Am. Jour. Sci. (3), Vol. XLII, 1891, pages 499-508. 



The authors identified the cldoritoids of Humboldt, of the Fitch and 

 the Champion mines, referred to briefly and only incidentally by the geolo- 

 gists who had studied the district, as a triclinic chlorite similar to masonite. 

 It occurs "in altered arkoses or similar rocks, in one case both in the cement 

 and in the basic and acid pebbles of a conglomerate." They also find that 

 the hornblende in tlie "actinolite" or " anthophy llite " schists, associated 

 with the ores, especially of the western portion of the Marquette area, is a 

 monoclinic iron-amphibole or a griinerite. 



Van Hise, C. R. The preCambrian rocks of North America. Conipte-rcndu 

 5tli sess. Internat, Cong. Geologists, Washington, 1891, pages 109-150. 



This article is a condensation of the eighth chapter of the correlation 

 bulletin on the Archean and Algonkian of North America which is referred 

 to on pages 133—135. 



MON XXVIII 9 



