GEOLOGICAL EXPLOKATIONS AND LITERATURE— 1S8L 89 



all these cases the (-(.uiiloinerates arc associated with the ineiul)ers of the 

 quartzite t'oniiatiuu near the liraiiite. 



Other couo'loiuerates of a different nature were found above the iron- 

 bearing formation. These are geuerally coarse (luartzite-conglomerates, 

 composed partly of rounded waterworn pel)bles, partly of angular tnig- 

 nieuts of Hinty quartzite, of red-banded ferruginous jasper, of novaculitic 

 or argillitic schist, and of other rocks. At the Cascade mine the conglom- 

 erate has "partly the structure of a very coarse sandstone with a micaceo- 

 ferruginous cement, l)eing partly formed of an agglomeration of large 

 pebbles and angular fragments, some of which have the size of a man's 

 head, which are all iirndy cemented together l)y a micaceo-chloritic, sandy, 

 mterstitial mass, often disseminated with granules of martite. The pebbles 

 are o-lassy or flinty quartzite, jasper-banded siliceous iron ores, novaculitic 

 and aro-illaceous slate fragments, and dioritic rocks. Tliesc conglomerates 

 have the thickness of from 50 to 60 feet, and can l)e followed in one con- 

 tinuous sheet all the way east to the Gribben mines" (pp. 66-67). Among 

 the other occurrences of this conglomerates and breccia, descril)ed are those 

 of the Home, Jackson, Cleveland, Gibbon, Salisbury, Lake Superior, 

 Champion, Saginaw, Goodrich, Keystone, Repuldic, and Michiganmie 

 mines. Although the full significance of the widespread occurrence ot 

 this conglomerate above the ore formation was not realized, Rominger 

 nevertheless was led liy its existence to suggest " that disturbances of not 

 oidy a local extent nmst have occurred at the end of this era of iron 

 sediments." 



In discussing the iron-ljearing formation the autlmr declines to admit 

 the existence either of the two imn formations »)f Brooks or ot his two 

 quartzites. Only one iron-bearing fonnation is recognized b}' the author, 

 and onlv one (quartzite, and this is the upper (juartzite of Brooks. 



The surface rock of the environs of ^'egauiiee and Islipeming is almost exclu- 

 sively formed of the iron-bearing rock series. * * 



The strata are in an extremely disturbed condition, folded and distorted in every 

 possible way, usually without causing a rupture of the beds, but in some other 

 Instances the laminated banded seams composing the thicker ledges have ruptured, 

 and the ends often came in a faulted position to each other, and were so recemented 

 by the siliceous groundmass. * * * These disturbed beds lie, in every instance, 



