In the northwestern sub-province of the pre-Cambrian Shield there are five major “bands” or “belts” of early pre-Cambrian sedimentary rocks. These are approximately parallel to one another and trend east-northeast. The southernmost, lying largely in Minnesota, is formed by the Ogishke-Knife Lake series. North of this lies a similar belt of rocks, the Seine series. Both have been studied and reported on in some detail.1 In the Manitou district, there is a series of sediments, the Manitou series, which, though less extensive than either the Seine series or the Ogishke-Knife Lake rocks, has been traced about 70 miles along the strike.2
North of the Manitou region is a fourth belt of sediments, running from Lobstick Bay of Lake-of-the-Woods to Savant Lake (Pl. 175, fig. 1). Though this is not actually a continuous belt of sedimentary rocks, the general linear distribution, over 200 miles, and the thickness, 9000 to 16,000 . . .