The Topsy occurrence is located west of the Lardeau River, between Rapid and Poplar creeks, in the Slocan Mining Division.

Regionally, the area lies within the Selkirk Mountains of southeastern British Columbia. The occurrence is within the Kootenay Arc, a curving belt of highly deformed metasedimentary and metavolcanic rocks which includes the Upper Proterozoic Horsethief Creek Group, the Upper Proterozoic to Lower Cambrian Hamill Group, the Lower Cambrian Badshot Formation, and the Paleozoic Lardeau and Milford groups. The volcano-sedimentary sequence is intruded by numerous Paleozoic to Mesozoic granitoid plutons.

The Lardeau River area of the Selkirk Mountains is mainly underlain by massive pillow lavas, volcanic breccia and green phyllitic rocks of the Index Formation and by grey-green mica schist of the Broadview Formation. Grey phyllitic rocks and marble of the Milford Group are exposed near the edges of the Mesozoic Mobbs Creek, Rapid Creek and Poplar Creek stocks. All rocks have undergone regional metamorphism to middle or upper greenschist facies. Rocks of the Milford Group have also been affected by thermal metamorphism (Geological Survey of Canada Bulletin 193).

No geological description could be located for this occurrence but it is probably similar to the Calumet and Hecla occurrence (082KSW094). Rocks in the vicinity of the occurrence are micaceous schist of the Index Formation of the Paleozoic Lardeau Group. The property has been explored by at least two small adits and one tonne of material was mined in 1907 to produce 156 grams of silver and 50 kilograms of lead. The adits are located on Lot 6492.