The area lies within the Shuswap Metamorphic Complex along the northwest 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 metasedimentary rocks. The metasediments consist of calc-siliate gneiss, quartzite, hornblende gneiss and marble.

Sillimanite occurs within the metasediments at the head of Blais Creek.