Strata underlying the region of the J showing, from oldest to youngest, include: quartzite and dolomite of the Middle Proterozoic Mount Francis Formation (Purcell Supergroup); conglomerates and coarse clastic sediments of the Upper Proterozoic Toby Formation (Windermere Supergroup); slates, quartzites, grits and conglomerates of the Upper Proterozoic Horsethief Creek Group; argillite and dolomite of the Cambrian to Ordovician McKay Group; dolomites of the Cambrian Jubilee Formation; dolomite, shale, sandstone and quartzite of the Ordovician to Silurian Beaverfoot Formation; argillite, argillaceous limestone and quartzite of the Middle Devonian Mount Forster Formation; and thin to medium-bedded biowacke stones of the Upper Devonian Starbird Formation. The strata form a broad, north plunging anticline, with numerous minor folds generally overturned to the east.

Copper mineralization was explored in 1967 by Kodiak Mines Limited. Six trenches with a total length of 91 metres were excavated in bedrock and mapping was carried out. This work outlined copper mineralization over a length of 143 metres and vertical range of 75 metres.

Copper mineralization occurs in quartz veins and stringers along a "shale-andesite" contact near a ridge crest. On the west side of the ridge, the showings consist of two sub-parallel quartz veins up to 1 metre in width that strike easterly. Chalcopyrite, malachite and azurite occur in the quartz veins and stringers and along fractures in the adjoining shales and andesites. Assays vary up to 2.37 per cent copper across 0.76 metre with the best composite section averaging 0.56 per cent copper over 6.9 metres (Assessment Report 1254).

Near the top of the ridge and down the eastern slope, the zone breaks up into a number of mineralized quartz veins and stringers in andesite and amygdaloidal andesite. Chalcopyrite, chalcocite and malachite occur in the quartz and chalcopyrite was found disseminated in the andesite. The stringers were observed to become widely spaced to the east and the veins were covered by overburden to the west.

Imperial Oil held the area as the Toby claims in 1978 and conducted geochemical and airborne radiometric surveys while searching for uranium, however no mention is made of the J showings.