THE EASTERN AEEA. 419 



numerous ramifying veins of these supposed conglomerates are all secondary 

 this phase of the conglomerate ought to be placed with the basic eruptives 

 of this area. 



SECTION VI —STRATIGRAPHY. 



Lithologiral evidence «*• to equivalence iritli tlic main Fenokee area. — The 

 lithok)g'ical character of the rocks described as Itelougtng to tlie Iron-bearing 

 member, the fragmental and ferruginous rocks soutli of the greenstone- 

 conglomerate, and the fragi>'ental and ferruginous i-ocks north and east of 

 the greenstone-conglomer-ite, closely resemble belts in the Peuokee series 

 to the westward. So far as the Iron-bearing member is concerned there is 

 identity. The ferruginous and fragmental rocks north and south of the 

 greenstone-conglomerates ditt'er from the fragmental nK-ks to the westwaid, 

 in that nonclastic is luingled with the clastic material. Aside from this dif- 

 ference, the above belts of the eastern area are the exact parallels of belts 

 in the main area. The lithological evidence, then, indicates that the eastern 

 area belongs to the same great jjeriod of time as the Penokee series to the 

 west. 



The only (piestion, then, which needs here to be discussed is whether 

 the greenstone-conglomerates belong to this same series. It ap[)ears to 

 me that all the facts indicate that they do. The data upon w'mcIi tliis 

 opinion is based are as follows : The conglomerates are inextrical)l\- mingled 

 and iiiterlamiuated with black, cleaved, unmistakably fragmental slates. 

 That these slates and greenstone-conglomerates have a common age can 

 hardly be doubted, for there appears to be every gradation Ijetween the two 

 classes of rocks. This fact is strong lithological evidence for placing these 

 rocks in the Penokee succession, where similar slates are so largely developed, 

 and not in the Southern Complex or in the Keeweenaw series to the nortli, 

 where no such rocks are known, noi- in the clierty limestone series, with 

 which they have no apparent connection. 



It may 1)6 asserted that the greenstone-conglomerates are more altered 

 and obscure than any other I'ock in the Penokee series. This argument 

 loses its force when the unusual nature of the materials of which thev are 

 composed is considered. The great mass of the fragmental rocks of the 



