10 Wiscojisin Academy of Sciences, A its, and Letters. 



account of a trip made from the interior of Wisconsin to 

 Lake Superior, by way of Long Lake and White river, by Dr. 

 Randall, one of the assistants under Dr. D. D. Owen, then in 

 charge of the geological survey of Wisconsin, Iowa and Min- 

 nesota. He gives a detailed description of all the rocks seen, 

 but says nothing of any that could possibly be Huronian. I 

 infer their absence, or entire concealment by drift material. 



This question of a western continuation of the iron belt of 

 Penokie range opens an interesting field for further investigation 

 the question being one of economic importance, quite as much as 

 of scientific interest. We have absolutely no facts going to 

 show the entire absence of the Huronian in the southern ends 

 of Bayfield and Douglas counties. The wonderful quantities 

 of iron which the strata of this series carry everywhere on the 

 south shore of Lake Superior, makes this investigation of such 

 importance that it should be undertaken at an early day by the 

 geological survey. The dip needle will soon tell the story, 

 even if the rocks are entirely concealed by drift. 



The rocks of the Huronian group in northern Wisconsin 

 are siliceous schists, talco-siliceous schists, white quartz rock, 

 very peculiar black slates of unknown lithologir.al affinities, 

 magnetic and specular schists and slates, banded magnetic 

 schists (alternating bands of magnetite and jasper or quartz), 

 metamorphic diorites, and diorite schists. In Ashland county 

 the whole series divides naturally into three portions. The 

 southernmost,' lowest or oldest portion is composed mostly of simple 

 siliceous schists with some granular white quartz, grey quartzite 

 and black slate. The central portion, consists of magnetic and 

 specular slates and schists, whose content of the oxyds of iron 

 varies from a fraction of one per cent, to sixty and even eighty 

 per cent, in which latter case the schists are iron ores. In 

 this portion of the group occur all the famous ores of the 

 Penokie Range — and indeed all the ores whose existence is yet 

 known — these ores being never intercalated lenticular masses, 

 independent of the enclosing rocks, but simply portions of the 



