LAKE SUPERIOR FORMATIONS 15 
in the Lake Superior region are of the same age, we find that 
the Upper Huronian has in many cases been pierced by them, 
but that the Animikie always overlies them. 
The conclusion seems inevitable that the Animikie is later 
than the Upper Huronian. If this is accepted, or if the Upper 
Huronian is accepted as the equivalent of Van Hise’s Ogishke 
Conglomerate (his Lower Huronian), or if Lower Huronian is 
accepted as a preferable term for Archean Schist, if any one of 
these propositions is accepted as proved it seems to me the 
others should follow. 
The succession in Lake Superior would thus be as follows: 
Cambrian. 
Keweenawan. 
Animikie. 
Upper Huronian. 
Lower Huronian. 
It may be urged that because of the enormous time break 
between the Lower and Upper Huronian, as here defined, the 
same name should not be applied to both systems. Providing 
that it is recognized that the terms are descriptive of systems, 
not of formations, it seems to me that they are quite as appro- 
priate as Lower and Upper Marquette, Lower and Upper-Cre- 
taceous, etc. Moreover, in the reconnaissance work in the 
immense unsettled districts north of the great lakes, it is a dis- 
tinct advantage to have a general word like ‘‘Huronian”’ to 
embrace the two systems which are easily separated from the 
remaining Archean, but are not easily separated from each 
other. Many areas have been mapped by the Canadian Survey 
as Huronian, which may or may not contain both systems. 
That will require more detailed work when the regions become 
more accessible. 
There remains the question of a term of systematic value to 
designate the pre-Cambrian series. Should they be called 
Archean, Algonkian, or something else? The Lower and Upper 
Huronian, and those vast areas of eruptive granite-gneisses, 
which are mainly of post-Upper Huronian age, undoubtedly 
