The Upper Cambrian Munising sandstone bordering the southern shore of Lake Superior is divided into three members: the basal conglomerate, Chapel Rock member, and Miner's Castle member. Heavy mineral similarities indicate that the Chapel Rock member may be correlated with the Dresbach of Wisconsin. The Miner's Castle member disconformably overlies the Chapel Rock member. Variations in sorting and mean grain diameter through the Miner's Castle member indicate transgressive and regressive depositional environments. Variations in the heavy mineral suite, particularly in garnet content, indicates that the Miner's Castle member is transitional between the transgressive Franconia sandstone and the regressive Jordan sandstone.