The Evening showing is described as a conformable sulphide horizon of dark massive sphalerite and galena within black cherty shales (Assessment Report 6545). It is located about 40 metres east of Cunningham Creek, 3.8 kilometres northwest of Roundtop Mountain, and 17 kilometres southeast of Barkerville. This showing, and several similar occurrences nearby, some with associated barite, are within a succession of mainly dark grey slates and limestones assigned to the Hardscrabble Mountain and Bralco successions of the Upper Proterozoic-Paleozoic Snowshoe Group (Geological Survey of Canada Memoir 421; Open File 2004-12). These lead-zinc-barite occurrences may be sedimentary exhalite deposits (Fieldwork 1997, pages 13-6 - 13-7).

In 1977, a 40-centimetre chip sample across the mineralized layer at the Evening showing assayed 0.99 per cent lead, 3.25 per cent zinc and 7.89 grams per tonne silver (Assessment Report 6545).

Work in 1976 led to recognition of an 8-kilometre belt of shales, phyllites and limestones in the vicinity of Roundtop Mountain containing conformable bodies of galena, pyrite, sphalerite and barite. One hundred and forty-one claims known collectively as the Cunningham Creek Claims, were subsequently staked or optioned by Riocanex. In 1977, Riocanex conducted soil sampling and geophysical orientation traverses were carried out using both Maxmin and Double Dipole EM, Self Potential meter and magnetometer instruments. A backhoe was used to dig 1.6 kilometres of trenches across geochemical anomalies and sulphide showings, and two diamond-drill holes totalling 94 metres were directed at a coincident geochemical and geophysical anomaly. In 1977, a short trench that was excavated over the Evening showing failed to expose further mineralization. In 1978, the trench was extended uphill with the same result. Bedrock included a varied sequence of black shales, green-brown ankerite, phyllites, coarser clastics and limestones. In 1978, Riocanex continued exploration with a programme that included 934.4 metres of diamond drilling in ten holes at the A Zone, the Vic-Beamish area, the X Anomaly and the Bralco showing; 2295 metres of backhoe trenching, most of which was directed at targets on the west flanks of Roundtop Mountain; 1200 metres of trenching with a D8 Caterpillar bulldozer at the A Zone; 3158 geochemical soil samples, and detailed geological mapping of the A Zone and trenches elsewhere.