332 THE MAKQUETTE IKON-BEAEING DISTEICT. 



of the jasper may be seen about Ishpeming- and Negaunee, southt 

 east of Pahnev, and at Republic. The niagnetite-griinerite-schis- 

 makes proniuieut exposures southeast of the Goodi-ich mine, at 

 Mount Huniljoldt, at Champion, and at Repubhc. In general, 

 where the Goodrich quartzite is in contact with the iron-bearing 

 formation the former is the more resistant rock. The same is true 

 ' of the Ajibik quartzite along the Cascade range, and where 

 graywackes are abundant at tlie upper part of the Siamo slate 

 this occupies the higher lands. Hence, upon the whole, the iron 

 formation is not well exposed, and occupies depressions, either 

 between intrusives within the iron formation or between the 

 underlying and overlying formations. 



Beginning at the east, the two long arms of the iron formation 

 constitute two synclinal troughs. As a result of the general west- 

 ward pitch of the series, the noi'thern tongue is known to termi- 

 nate to the east, but the termination of the southern trough is 

 undetermined because of its disappearance below the Pleistocene 

 sands. As another consequence of the westward pitch, these two 

 tongues and other shorter ones unite into the broad Ishpeming 

 and Negaunee synclinorium. The continued westerly pitch of 

 the series brings the quartzite of the Upper Marquette to the 

 surface at Ishpeming, and this di\'ides the Negaunee formation 

 into two arms, one of which extends along the south side of the 

 Marquette disti'ict and the other along the north side. Therefore, 

 west of Ishpeming the formation appears in two belts on opposite 

 sides of the great synclinorium. At Lake Michigamme an inter- 

 mediate anticline becomes prominent, and as a result of it a 

 synclinal arm extending southeast, terminating at Republic, is 

 produced. West of the Republic fold is another very similar 

 one. In the large Ishpeming-Negaunee area the secondary 

 folding of the formation, combined with the distortions of the 

 intrusions, produces extremely complicated contact lines, both 



