The area lies along the western margin of the Frenchman Cap Dome. The core of the dome is composed of a mixed paragneiss and orthogneiss succession of probable Aphebian age, and is mantled by an unconformably overlying succession of metasediments locally intruded by a suite of nepheline syenite gneiss.

The nepheline syenite gneisses are grey weathering, medium to coarse-grained rocks, forming a concordant, north trending, west dipping body within the metasedimentary envelope of the Dome.