82 THE PENOKEE IRON BEARING SERIES. 



(2) the Iron-l)eiiriiin- slatci .series, in large measure composed of little 

 altered f rag-mental rocks. The u})permost of these successions, it is main- 

 tained, is ])lainly enough the eqtiivalent in general of the original Huronian 

 series of Canada, and shiudd be so called. To the lower series we may 

 for tlic prescuit apply the (Janadian term, Laiu'entian. This lower group 

 may or may not ))e further divisilde into subordinate nundiers; and indeed 

 there are here and tliere indications of subordinate lireaks in tlie ujjper 

 series, l)ut for the present the only distinct and widely applicable classiiica- 

 tion to ))e made is that above indicated. 



The proofs cited in favcjr of the conclusions presented in this paper are 

 drawn in very large measure indeed from the Penokee district. Since the 

 same facts are presented nmch more fully in tlie pi-esent volume, it is not 

 desiral)le to i-epeat them in this connection with any detail. We merely 

 copy from the paper the tabulated statement that proofs of unconformity in 

 the Penokee district were found. 



1. Ill Mie iiiaiiiier ill wliicli the rcf^iilarly suc-t'eeding: belts of the higher series 

 traverse the courses of tliosc of the lower. 



2. In the strong eoiitriist between the two .series as to rock kinds, the bedded 

 members of the lower .series having arrived at a nearly complete recrystallization, 

 while those of the higher are l>ut little altered. 



.'*.. Ill the hii;hly folded and contorteil condition of the lower .series, as contrasted 

 with the unfolded cuiiditioii and sini])le stratigrapliy of tlie higher. 



4. In the striking contrast between the contacts of the granite with the lower 

 .schists and with the higher slates, the former liciiig invaded by it in an intricate 

 manner, the latter never when tlie two conic together, ((iranitc in veins ami inter- 

 secting masses occurs among the upper mica schists of the I'enokee series (see map), 

 but this alwa.vs of a dillerent character from the granite at the s<mthern contact, 

 which has, as yet, never lieen found to intersect the slates.) 



5. In tile discordant laminations of the two sets of rocks when seen in contact 

 or close |)ro\iiiiily. 



(». In the occurrence in the n[)per series, not only at horizons above the V)ase, 

 but also at jioints on tlie contact line, of almiidant detrital material derived trom the 

 lower series. 



luviNO (R. 1).). Preliminary Paper on an Investigation of the Archean Forma- 

 tions of the Northwestern States. Fifth Annual Report U. S. Geol. Survey, 1S85, 

 ])p. l7.")-2t2. 



