A layered series of granitic, sedimentary and altered volcanic rocks occurs in the Lily Pond Area of Southeastern Manitoba. The sedimentary and volcanic rocks are bands or sheets conformably enclosed within and between quartz diorite, granodiorites and quartz monzonite bands or sheets which are structurally concordant to a central domed quartz diorite mass. Field work and a petrographic study of specimens of the rocks showed that the granitic rocks could be instrusive crystallization differentiation fractions from a common parent basaltic melt. The liquid fractions were emplaced as upward and westward moving sheets which intruded a volcanic-sedimentary complex and left parts of this complex as remnant bands within the instrusive series.