The consolidated rocks of three-quarters of the Province of Manitoba are of pre-Cambrian age. Our geological knowledge of these rocks has been derived from two types of exploration, namely, track surveys with geological notes, performed by Bell, Cochrane, Tyrrell, Dowling, and McInnes, and more detailed geological surveys made during recent years in the areas where active prospecting for minerals has been carried on. It is the object of the present paper to correlate as far as possible the more recent information which has been obtained. No attempt is made to apply the nomenclature adopted for the pre-Cambrian succession of any of the geological subprovinces along the southern border of the Canadian shield, and the only comparison offered is with the succession found in the Rainy Lake area of Ontario—a region which is geographically the nearest and geologically the most similar of any area outside the Province of Manitoba where . . .