At the Fenster Creek showing, quartz-calcite-barite veins cut strata of the Helikian Roosville Formation (Purcell Supergroup) consisting of siltstone, sandstone, argillite, quartzite and dolomite, in the southwestern part of the MacDonald Range. Three barite occurrences were discovered along the crestal region of the Wigwam anticline. The veins are steeply dipping fracture-fillings that vary in thickness from a few centimetres to over one metre.