The Gavin Creek showing outcrops along Elusive (Gavin) Creek, 1.15 to 1.45 kilometres north-northwest of the confluence of Siwash and Galena creeks, and 39.5 kilometres north-northeast of Princeton.

A diatreme is hosted in a quartz porphyritic monzonite stock ("quartz-eye porphyry") of the early Tertiary Otter intrusions, within granite and granodiorite in the western margin of the Middle Jurassic Osprey Lake batholith. This is one of a number of small pipe-like intrusive bodies developed along a possible north-trending fault zone following Siwash and Elusive creeks. This diatreme trends northwest for 300 metres and is up to 120 metres wide on surface.

The diatreme is comprised of pebbles of rhyolite, quartz-eye porphyry, granite, basalt and diorite, 1 to 20 centimetres in diameter, in a fine to medium grained, highly weathered and bleached matrix. Minor phyllic alteration is evident.

Small amounts of chalcopyrite, sphalerite and galena occur along fractures and in narrow quartz veins cutting the diatreme. One 0.50-metre section of drill core assayed 0.116 per cent copper, 0.001 per cent molybdenum, 0.388 per cent lead and 1.52 per cent zinc (Assessment Report 9424, page 37).

The showing was explored by Brenda Mines Ltd. between 1979 and 1981. The company conducted geological, and soil and rock geochemical surveys, and drilled one hole, 194 metres long.