The Pewter showing is found on the west side of Frances Bay (formerly Fanny Bay). This occurrence is along strike and across the bay from the Galena showing (MINFILE 092K 031). These two occurrences have identical settings and mineralization and are assumed to lie on the same vein.

The area around Frances Bay is underlain by granodiorite, and to a lesser extent quartz diorite, of the Jurassic to Cretaceous Coast Plutonic Complex. What has been described as a shear vein system, or fissure vein, crosses the bay with a strike of 053 degrees and vertical dip. The vein is 2 to 3 metres in width, composed primarily of quartz with epidote and chlorite, and is contained within the granodiorite. On the west side of the bay, four small, partly assimilated inclusions and/or screens of metasediments and metavolcanic rocks are evident. Mapping by the Geological Survey of Canada identified malachite on the east side of the bay (Geological Survey of Canada Open File 480).

Mineralization is found with the quartz in the shear. Small veinlets crisscross the shear and contain disseminations as well as blebs of sphalerite, galena and pyrite. Small surface trenches have traced the mineralized structure for approximately 50 metres to the southwest.

In 1984, a chip sample (84-P-3) for gold and silver only from the left side of the adit assayed 12.3 grams per tonne silver and 0.2 gram per tonne gold over 1.0 metre (Assessment Report 12722).

Prior to 1929, a shaft was sunk to a depth of approximately 5 metres and then excavated laterally for approximately 11 metres. In 1984, Iron River Resources completed a program of rock sampling and geological mapping on the area as the Pewter claims. In 2011, the area was prospected by G.N. Goodall.