THE GEOLOGICAL SECTION OF MICHIGAN 685 
c) Wewe slates. The slates of Goose? Lake, rarely left by the 
erosion, but exposed on Carp River, Sec. 5, T. 47 N., R. 25 W., and 
on Sec. 12, T. 47 N., R. 26 W., black and gray slates........ 300 ft. 
Mio-Huronian.—This we are inclined to believe is the main iron- 
bearing formation, not only of the Marquette. range, but of the 
Menominee range as well. During this time began an epoch of 
basic volcanics at numerous points which continued into the neo- 
Huronian and expressed itself mainly in intrusives altered to amphib- 
olite (“‘diorite”), chloritic schist, ‘paint rock,’’ and uralite diabase 
in the mio-Huronian, and mainly in effusives and tuffs in the neo- 
Huronian. 
This is Van Hise and Leith’s Middle Marquette; compare also 
Wadsworth’s “Republic” and ‘‘Negaunee”’ formations.? 
a) Ajibik quartzite. Has often been confused with Mesnard 
quartzite. Grades upward through slaty phases into 0)...... 700 ft. 
6) Siamo slate. Grits, flags, and graywackes, and graywacke 
slates, with volcanic tuffs........... Sia ie Reet SB RM ty aN pea, 600 ft. 
c) Negaunee formation. The main formation of cherty carbon- 
ates and siliceous beds with “greenalite” readily altering into jas- 
pilitic) ivon-beaning formation. ._.).4ses ease lees 1,000 ft. 
_ Near igneous contacts it also changes into griinerite, and other 
amphibole-magnetite schists. 
Neo-Huronian (Animikie).—The relations of this series around 
Port Arthur on the north side of Lake Superior and along the Gogebic 
range on the south are such, both as to the overlying and underlying 
rocks, that there can be but little doubt that they are in general 
coeval, and the graphitic slate horizon of the upper part seems to be 
widely identified. We have no hesitation in adopting the term 
Animikie. There may be some question as to whether it belongs in 
the Huronian at all. We believe Lawson considers the greatest and 
most profound unconformity? to come at the base of this formation, 
rather than for instance, between the Mesnard and the Keewatin or 
1 Wewe is Chippewa for ‘‘ goose.” 
2 Though he was never quite able to agree with what seems to us the proper inter- 
pretation of the stratigraphy of the same, so that the order as given on p. 66 differs 
so much from our views that we could hardly use it without producing confusion. 
See 1892 Report, pp. 64, 66, 110, etc. 
3 The Eparchean interval. 
