58 



University of California. 



[Vol. 3. 



Huronian is not present in the Animikie. Conglomerates are 

 scarce or absent in the Animikie; they abound in the Huronian. 

 Laminated cherts occur in the Animikie; they are absent in the 

 Huronian. Quartzites, it is true, occur in both series, but even 

 here the physical condition of the rocks in the two series is 

 distinctly different. Iron ores characterize the Animikie; they 

 are lacking in the (Upper) Huronian. Silver ores characterize the 

 veins of the Animikie; they are lacking in the (Upper) Huronian. 

 The (Upper) Huronian is pierced by granites; the Animikie is not. 

 Such is the lack of petrographic and stratigraphic parallelism 

 upon which the Animikie and (Upper) Huronian are correlated on 

 purely petrographical grounds ! 



But it may be urged that the Animikie of Thunder Bay and 

 the Huronian of Lake Huron are sufficiently far separated geo- 

 graphically to account for the difference in stratigraphic com- 

 position in the two areas. If this be conceded, so much the 

 worse for a correlation based on petrographical characteristics, 

 and unsupported by other evidence. But the Animikie basin is 

 not so remote from the Huronian. On the north side of Lake 

 Superior I have followed the characteristic black shales (slates) 

 of the Animikie to the islands east of Battle Island, their last 

 outcrop above the waters of the lake being not more than 190 

 miles from the Huronian area. On the south shore, the Lake 

 Superior syncline brings up the characteristic Animikie strata in 

 the Penokee Range. No one has ever questioned the correlation 

 of the Penokee with the Animikie. The Penokee has been cor- 

 related by Van Hise and his collaborators on the geology of the 

 south shore with the Upper Menominee, the upper series at 

 Crystal Falls and with the Upper Marquette ; and Marquette is 

 only about 140 miles from the Huronian area in the line of the 

 general strike of the rocks. 



These upper series of the south shore, the Penokee, the Upper 

 Menominee and Upper Marquette have the same general petro- 

 graphic and stratigraphic character as the Animikie, viz: A 

 lower quartzite formation and an upper slate formation, with 

 subordinate beds of siderite and ferruginous chert. With 

 such a persistence of character, indicating widespread uniformity 

 of continental conditions during the time of accumulation of the 



