C URRENT PRE- CA MBRIA N LITER A TURE 1 9 5 



Lake, and of an area on the west side of Outlet Bay, in the corners of 

 sections 13, 14, 21, and 32, T. 63 N., R., 17 W., and along the shore 

 for one half mile westward. 



It is evident that the Stuntz conglomerate on the south shore of 

 Vermilion Lake is a true water-deposited conglomerate, of the same for- 

 mation as the slates and graywackes of the district, the conglomerate 

 grading into the quartzite and graywacke, and this into argillaceous 

 slate. Furthermore, as supposed by Van Hise, the conglomerate lies 

 unconformably on the iron-bearing formation, and contains very 

 numerous fragments of jaspilite. The position of this unconformity, 

 whether at the base of the Taconic or lower is not ascertained. 



The nature and position of the conglomerate in the valley of the 

 Puckwunge, a small stream entering the Pigeon River north of Grand 

 Portage, is discussed. This conglomerate is overlain by igneous rocks, 

 resembling the traps of the Keweenawan. The subjacent formation 

 cannot be certainly determined, but in the same locality, at a lower 

 level, is a slate rock, called the Puckwunge slate, which was followed 

 for some distance north and east, and which is probably an upper 

 member of the Animikie, not before individualized. The conglomerate 

 contains quartzite pebbles, which are referable to the quartzites of the 

 Animikie, farther north. It may be inferred that this is the basal con- 

 glomerate of the Keweenawan, which has been identified up to Grand 

 Portage island, and at intervals along the Lake Superior coast, from 

 Baptism River to near Beaver Bay. 



Winchell J discusses some resemblances between the Archean of Min- 

 nesota and of Finland. The succession in northeastern Minnesota, as 

 made out largely from field work done in 1897, is as follows, in descend- 

 ing order. 



1. Granitic intrusion, cutting and metamorphosing the earlier schists 

 and fragmentals. This rock is seen about Snowbank Lake and Moose 

 Lake, about the western confine of Disappointment Lake, and at Keke- 

 quabic lake. 



2. Upper Keewatin. — This consists of conglomerates (at Stuntz Island 

 and at Saganaga and Ogishkie Muncie lakes), sericitic schists, quartzose 

 and micaceous schists, graywackes, clay-slates, chloritic schists, and 

 porphyroids. The mica-schists, embracing many conspicuous bowlder- 



' Some resemblances between the Archean of Minnesota and of Finland, by N. H. 

 Winchell : Am Geol., Vol. XXI, 1898, pp. 222-229. 



