438 THE PENOKEE llfON-BEARlNG JSEKIES. 



part of Sec. Ki is an exposure of" green seliist belongiug to the basement 

 complex; so that most of tlie nortliern swing- occurs before this ])oint is 

 readied. Tlie reUxtions are sucli tliat it is jjossiljle to explain this sudden 

 change in direction bv a sharj) curve, but it is jjossible that it is wholly or 

 in part due to a fault. Sunday lake and the surrounding low ground make 

 it not eas>- to settle this cjuestion. However, at none of the places men- 

 tioned is it known that there has been any actual faulting. Throughout 

 the whole length of the series, which has been subjected to two great oro- 

 grajdiic movements, no dislocations great enough to make the belt difficult 

 to follow have occurred : I)ut at thnn* places there is pretty decisive proof 

 that fiiulting has taken ))lace to some extent. 



Fault at Bad river.— V\\e most considerable fault is that at Bad river, 

 in R. 3 W., Wisconsin. The relations of the exposures and the line of fault 

 have been accurately mapped and described by Prof. Irving.' PI. xxxvi is 

 wholly from data furnished h\ this map. The explanation is also largely 

 taken from Prof Irving, it <inly being modified to correspond witli the 

 present understanding of the succession of l)elts. West of the line marked 

 "Supposed position of fault line" the layers of the Penc>kee series follow in 

 the regular order. Neai- the base of the left hand side of the plate are 

 mapped large exposures of granite and gneiss. North of these on Bad 

 ri^•er, and very close to the gneiss are ex])Osures uf the Cherty lime- 

 stone member. Next follows the Quartz-slate, which is exposed through- 

 out its whole thickness, having, as usual, as its upper layer a vitreous 

 quartzite. Just above this quartzite follow the exposures, which rise in high 

 cliffs al)o\-e the i-iver, belonging to the Irondiearing member. The}' are so 

 numerous and large that they ])ractically show the whole thickness of the 

 formation. Upon the nortli side of this bluff is a thin layer of garnetiferous 

 magnetitic slate, which })asses into a garnetiferous black slate, ])lainly con- 

 stituting the base of the Upper slate member. North of this point are 

 a number of large exposures belonging to this belt. On both banks of Bad 

 river is sliown a large exposure of diabase. East of the "Supposed line of 

 fault" the succession of belts in the Peuokee series is found to be identical 

 with that just given, tlie oidv diflFerence being that liut a small part of the 



'Geol. of Wi.s. vi)l. Ill, [pp. IfiO-l.-iS, with accimiiiaiiviiij; iitlas, I'l. .vLxiii. 



