Gold is being mined at several places along a belt lying 50 miles north of Lake Superior, extending east from Lake Nipigon to Long Lake. The structural relations of the ore bodies at the following mines are briefly discussed--Northern Empire, Leitch, Sand River, Bankfield, Little Long Lac, MacLeod-Cockshutt, and Hardrock. Most of the ore bodies are in sediments. They occur in shear zones along the axial planes of minor folds, along bedding planes, along the contacts between dikes and sediments, and along the tips of tongues of porphyry stocks that intrude sediments. One vein occurs entirely in lavas.In general the ore bodies are localized where there is considerable heterogeneity in the country rocks. Basic volcanics show considerable variation in the degree of schistosity in different parts of flows, and veins occur in schistose zones lying between massive parts of successive flows.