Detailed studies of the “Knife Lake series” in the Vermilion district of northeastern Minnesota in the vicinity of Kekequabic and Ogishkemuncie lakes reveal two series of continental sediments separated by an unconformity of considerable magnitude. The sediments of the Knife Lake series, in contrast to the Lower Huronian series of the south shore of Lake Superior, are a more continental than marine type, more intensely folded, and are metamorphosed by intrusions of Algoman granite. The unconformity within the Knife Lake series adds one more contrasting feature to those previously described and supports the revised correlation by Leith, Lund, and Leith (1935) that “in the absence of proved age relations it seems undesirable that terms like ‘Huronian’ should be extended to include beds representing such contrasting types of sedimentation.” However, nothing in the present study suggests that the Knife Lake series is older than the Eparchean interval.