120 ALFRED R. C. SELWYN ON THE 
or whether they are a lower portion of the Animikie series not exposed in Canada, I am 
unable to say. Iam, however, at present unacquainted with any facts in connection with 
the typical or any other Huronian area in Canada, which would make it even probable 
that the Thunder Bay Animikie is the equivalent of the original Huronian, as is adyo- 
cated by Messrs. Irving and Winchell (Science Nos. 12, 13); and it must not be overlooked 
that this typical Huronian has now been traced in an almost continuous belt from the north 
shore of Lake Huron, north-east to Lake Mistassinnie in lat. 51, long. 73 west, and no- 
where, so far as I can judge, presents either physical or lithological “similarity” to the 
Thunder Bay Animikie series. And I hold this notwithstanding anything contained on 
p. 94 of the 10th report of the Minnesota Survey, referred to by Professor Irving (Science 
No. 13). 
It seems to me more probable that the Gunflint Lake beds are some lower part of the 
“ Animikie ” series, not exposed around Thunder Bay, and it may be that the upper part of 
the series has overlapped the lower in the same manner as it is itself overlapped, further 
east, by the Nipigon series and it again, still further east, by the Keweenian amygdaloid 
series. Perfectly analogous cases of overlapping of the different members of the Lower 
Paleeozoic rocks occur in the St. Lawrence and Ottawa valleys. 
As regards the 3rd point I have alluded to, the relative positions of the several 
subdivisions of Logan’s Upper Copper-bearing rocks, divided by Hunt into Keweenian, 
Animikie and Nipigon, I scarcely think any one will now be found to support the view 
advocated by Dr. Hunt—that the two latter are newer and above the Keweenian. The 
succession from the Thunder Bay series, “ Animikie,” upward to Nipigon and Keweenian, 
all dipping at low angles (from four or five to fifteen or twenty degrees) south-easterly, is 
so plain in proceeding eastward from Thunder Bay by Silver Islet to Nipigon and St. 
Ignace, that to my mind it leayesno room for doubt. To suppose that the Isle Royale and 
St. Ignace copper rocks are below the Nipigon is as opposed to the evidence as it would be 
to suppose that the Animikie was newer than the Nipigon. The absence of the Animikie 
at the surface around Black Bay is clearly caused by the overlapping I have referred to. 
Dr. Hunt, in his argument (Science, No. 8), jumps from the Nipigon of Black Bay and 
Nipigon Bays, north-side to Michipicoten Island, and apparently overlooks the south-side 
of Nipigon Bay and the exposures of the cupriferous amygdaloids there met with in the 
great promontory forming the south side of Black Bay, and terminating in St. Ignace, 
Simpson’s, Wilson’s, and other islands of this group, the strata of which clearly overlie, 
without apparent discordance, the so-called Nipigon division, and where also there are 
reasons for believing the Animikie re-appears from beneath it. The Mamainse and 
Michipicoten Island series are doubtless of the same age, but it seems probable that they 
occupy a distinct basin, divided from the much larger one, the margins of which are out- 
lined by Keweenaw Point on the south and St. Ignace, Isle Royale and Nipigon on the 
north. These trough-shaped basins are, perhaps, separated by a ridge of older rocks, extend- 
ing from the Slate Islands and the Pie River on the north-east to the neighborhood of 
Marquette on the south-west, or, what appears more probable is that the Michipicoten 
and Mamainse area, in which, according to Logan and Macfarlane, from ten to fifteen 
thousand feet of strata are exposed, is the end of the Isle Royale and Keweenaw Point 
trough (holding, according to Sweet, from 20,000 to 30,000 feet of strata), cut off by an 
