LAKE SUPERIOR FORMATIONS TT 
chert pebbles. In the Temiscaming region, also, banded jaspers, 
which are the source of the pebbles in the conglomerate, have 
been found within the area described by Logan as Huronian. 
Near Sault Ste. Marie banded quartz has been found within the 
Huronian area.' 
There can be no doubt that Logan in 1863 included within 
his Huronian two series—the one typically represented by the 
banded jaspers, the other by the slate conglomerate and the 
jasper conglomerate. This has been uniformly followed from 
that time forward by all Canadian geologists and by many 
American, the vertical green schists and their interbedded 
banded jaspers being considered Lower Huronian. These 
schists have also been mapped as Huronian in nearly every case 
by the Canadian Survey. It is true that Lawson, in his reports 
on the Lake of the Woods? and of Rainy Lake, describes simi- 
lar rocks as Keewatin, doubtfully correlating them with the 
Huronian north of the Georgian Bay. He recognizes, however, 
their resemblance to those of the Michipicoten area, a conclu- 
sion with which I agree. 
The lowest rocks at Michipicoten are greenstones, often 
ellipsoidally parted, and volcanic tuffs. Interbedded with the 
latter are cherty iron carbonates, pyritic quartz rocks, ferrugi- 
nous cherts, and ore bodies. Into these two are numerous 
intrusions of greenstone and granite. Above lies a slate con- 
glomerate. The resemblance to the Ely greenstone, Soudan 
iron formation, and Ogishke conglomerate as described by Van 
Hise3 is very close. The similarity of the two regions was 
pointed out by Coleman and Willmot in a paper published in 
1899,* and’ it 1s recognized by Van Hise in the present paper 
(pe-4in i). 
These schists and interbedded ferruginous sediments have, 
however, always been considered as Huronian or Keewatin. I 
see no reason for abandoning the term Lower Huronian for 
"Rep. Bur. of Mines, 1901, p. 187. 
2 Geol. Sur., Can., 1885, I, and 1887, III. 
3 Iron Ore Deposits of Lake Superior, p. 402. 4 Rep. Bur. of Mines, Ont. 
