398 COPPER-BEARING ROCKS OF LAKE SUPERIOR. 
Professor A. H. Chester of the rocks lying east and north of Vermillion Lake, 
I suspect that these greenish rocks are very close to schistose material inter- 
laminated with the gneiss at Penokee Gap, in Wisconsin. 
By Professor Chester’s kindness I am also in receipt of a large number 
of specimens collected by him around the east and south sides of Vermillion 
Lake for several miles, and thence southward to the Mesabi Range in town- 
ship 59. From these specimens and the notes accompanying them, and 
from the published notes of N. H. Winchell,‘ I gather that there is here 
a broad belt of schists trending in a general way something south of 
west, with a common very high dip, a little on one or the other side of 
vertical, and intricately folded. Professor Chester's specimens include: 
clay-slate, which he says is largely exposed about Vermillion Lake; silvery 
mica-schist, running into greasy-surfaced, aphanitic, siliceous. schist, which 
often suggests the rock of No. III of the Penokee series,” and is commonly 
very much altered and charged with hematite to such an extent as to con- 
stitute beds of soft hematite analogous to those of the Marquette region ; 
quartzites of several kinds; gray crystalline limestone associated with white 
quartzite, and precisely similar, both in nature and in this association, to 
beds in the Penokee, Marquette and Menominee regions; gray cherty 
schists like those of the Animikie Group; banded jaspery and cherty mag- 
netitic schists; banded quartzite and magnetite; lean slaty magnetites pre- 
cisely like those of the Animikie Group at the Mesabi Range and like 
those of the Penokee and Marquette regions; and rich specular iron ores. 
Between these schists and the flat-lying beds of the Animikie Group, in 
the region south from Vermillion Lake, is a broad belt of gneiss and gran- 
ite which is plainly the one crossed by Bell between Gunflint and Saga- 
naga Lakes. 
The strong lithological similarity of the Vermillion Lake iron-bearing 
rocks to those of the Animikie Group, and of the South Shore iron-bearing 
formation, makes it almost a certainty that these also are Huronian; while 
the connection of the Vermillion Lake schists with the schistose rocks 
northeast as far as Thunder Bay renders it nearly as certain that the latter 
! Ninth Annual Report of the Geological and Natural History Survey of Minnesota, p. 96 et scq. 
2Geolugy of Wisconsin, Vol. III, p. 111 
as 
