The rocks concerned, formerly identified as Lardeau series metamorphic rocks, occur over a large area on the west side of Kootenay Lake, mainly concentrated around the margins of the middle Cretaceous Bayonne batholith. As such, it is not realistic to assign a "showing" location; it is more an area, best defined by reference to Map 603A (to accompany Geological Survey of Canada Memoir 228) or Geological Survey of Canada Map 1714A. Sillimanite occurs with andalusite and kyanite in what are now mapped as Middle to Upper Proterozoic rocks of the Dutch Creek Formation (Purcell Supergroup) to Horsethief Creek Group (the "showing" location is in the former).