The Mary 1 showing is located along a roadcut on the north bank of the Similkameen River, 2 kilometres west-northwest of Hedley.

The showing consists of a quartz-calcite vein, 0.4 metre wide, mineralized with arsenopyrite, in black argillite of the Upper Triassic Stemwinder Mountain Formation (Nicola Group). The vein strikes 050 degrees, dips 80 degrees northwest and is associated with an adjacent late-stage, altered biotite feldspar porphyry dyke of similar strike. A rock sample analysed 6 grams per tonne gold, 2.5 grams per tonne silver and 1.71 per cent arsenic (Assessment Report 15864, Appendix A, sample R83572).

A green andesite porphyry dyke in Stemwinder Mountain Formation argillite outcrops on Highway 3, 350 metres south of the above vein, and strikes north-northeast for 76 metres. A sample of altered argillite adjacent to the dyke assayed 1.1 grams per tonne gold (Assessment Report 12905, sample 1).