454 THE JOURNAL OF GEOLOGY. 



Van Hise^ describes the Huronian volcanics south of Lake Superior. 

 These include both lavas and tufas interstratified with each other and with 

 contemporaneous elastics. Among the lavas are amygdaloids, the amygdules 

 of which are in certain cases jasper similar to that of the iron formation 

 adjacent, and believed to have been formed at the same jasper forming period. 

 The volcanics are much more altered than those of the K^weenawan. They 

 are found in various places, but the most extensive areas are in the Gogebic 

 district west of Gogebic lake, and in the Michigamme district north of Crystal 

 Falls. In the first locality the series is 7,000 or 8,000 feet in thickness. This 

 great mass of material was piled up, while to the west 700 to 800 feet of the 

 sediments of the iron-bearing formation were accumulating. In this district, 

 therefore, at the same time there was being deposited the ordinary sediments 

 of the area and locally a volcanic series of a wholly different character. 



^Bayley describes actinolite-magnetite-schist from the Mesabe range of 

 Minnesota. This rock differs from the corresponding schists of the Penokee 

 series only in that quartz is rare and hematite is absent. 



C. R. Van Hise. 



'The Huronian Volcanics South of Lake Superior, by C. R. Van HiSE. Bull. 

 Gaol. Soc. of Am., Vol. IV., pp. 435-36. 



^Actinolite-magneiite-schists from the Mesabe Iron Range, in Northeastern Min- 

 nesota, by W. S. Bayley. Am. Jour, of Sci., Vol. XLVL, No. 273, Sept., 1893, PP- 

 176-180. 



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