The Observer showing is located between Gumas and Washout Creeks, about 10.0 kilometres northeast of Alice Arm. Various showings in this area have been prospected for base and precious metals.

The region is underlain by an assemblage of volcanics and sediments comprising the Upper Triassic Stuhini Group and the Lower Jurassic Hazelton Group. This assemblage has been folded into a north-northwest trending anticline (Mount McGuire anticline) and regionally metamorphosed to greenschist facies.

The showing comprises a number of quartz, quartz-carbonate, quartz-barite and barite veins, breccias and a silicious replacement zone. The country rock consists of Hazelton Group augite porphyritic andesite, greywacke and tuff.

A quartz vein, 0.55 metre wide, occurs at 853 metres elevation on the west bank of Washout Creek. The vein is mineralized with pyrite, chalcopyrite, arsenopyrite and sphalerite. A sample from this vein assayed trace gold, 27 grams per tonne silver and 1.1 per cent copper over 0.55 metre (Minister of Mines Annual Report 1929).

A quartz-barite vein, similar to the Fox showing (103P 161) 2.8 kilomtres south, occurs 230 metres to the southwest at 968 metres elevation. Mineralization consists of chalcopyrite and pyrite. A sample assayed trace gold, trace silver and 0.2 per cent copper (Minister of Mines Annual Report 1929).

A silicious replacement zone, 2.0 metres wide, strikes 063 degrees and dips 40 degrees west at 975 metres elevation. Veinlets and disseminations of chalcopyrite and pyrite occur in bluish quartz. A 2.0 metre chip sample assayed trace gold, 3.4 grams per tonne silver and 0.9 per cent copper (Minister of Mines Annual Report 1929).

A brecciated quartz vein, 1.2 metres wide, strikes 168 degrees for up to 100 metres and dips 45 degrees east between 1067 and 1173 metres elevation. The vein is mineralized, along the hangingwall, with sphalerite, pyrite and galena over widths of 0.20 to 0.51 metre. A grab sample assayed trace gold, 110 grams per tonne silver and 8.7 per cent zinc (Minister of Mines Annual Report 1929).

At 1128 metres elevation, a barite breccia zone contains sphalerite, galena and minor chalcopyrite. A sample assayed trace gold, 30.8 grams per tonne silver, 0.04 per cent copper, 0.6 per cent lead and 2.9 per cent zinc over 3.0 metres (Minister of Mines Annual Report 1967).

Two short adits were driven prior to 1920 in the prominent iron oxide-stained bluffs above Gumas Creek.