The Jarvis Lake Barite showing is located approximately 91 kilometres north of McBride and 168 kilometres east-northeast of Prince George, on the north-facing slope of a mountain north of Jarvis Lakes. The showing is 15 kilometres west of the British Columbia–Alberta border, in the Cariboo Mining Division.

The region is underlain by an assemblage of sedimentary rocks that were deposited in a continental shelf environment along the western margin of Ancestral North America. This clastic and carbonate rock sequence ranges in age from Hadrynian to Upper Cretaceous and now lies within the Foreland tectonostratigraphic division of the Canadian Cordillera. Folds and southwest-dipping, northeast-directed thrust faults are the dominant structures of the region.

The Jarvis Lake Barite showing is hosted with the Mississippian Rundle Group, which is characterized by limestones, marbles and various calcareous sedimentary rocks. It is located within 100 metres of the contact with the Upper Devonian to Lower Mississippian Banff and Exshaw formations, which are characterized by limestones, slates, siltstones and argillites, and within 700 metres of the Upper Devonian Palliser Formation. The showing is on the north limb of a prominent, kilometre-scale fold.

At this location (near Monnius Mountain) a barite vein, greater than 1 metre wide and of unknown extent, is evident in Carboniferous Rundle Group dolomite near the upper part of the unit. The vein consists of coarse-grained, white barite; no base metal sulphides were detected.