In this paper I shall adopt the nomenclature employed for many years in the publications of the Canadian Geological Survey without at present making any attempt to justify it. The term “Archean,” then, will be used, not in the restricted sense advocated by Geikie,* nor in that held by Van Hise,† but in its broadest application, as embracing all the rocks stratigraphically inferior to the Animikie rocks of Lake Superior.
Its Boundaries.—The portion of the Dominion of Canada to which attention is here drawn may be briefly described as the southern half of Rainy River district, in the province of Ontario, lying between our transcontinental highway and the international boundary, and the Lake of Woods, in the west, to the western boundary of Thunder Bay district.
Geologically complex.—It would be difficult to imagine a more interesting field or one that offers such . . .