The region is underlain by (?)Hadrynian to Paleozoic Snowshoe Group rocks, which occur within the Barkerville Terrane of south-central British Columbia. These metasedimentary rocks consist primarily of marble, quartzite and phyllite which in the area of the Peter Gulch showings comprise the Downey succession (informal name). Metamorphism of the region varies from chlorite grade to sillimanite and higher. The lode gold deposits of the region occur in rocks metamorphosed no higher than greenschist facies.
The Peter Gulch showings occur adjacent and are similar to the Cariboo-Hudson occurrence (093A 071) but at a lower elevation. In addition to quartz veins with sulphides, a replacement deposit occurs within limestone in a zone up to 1.2 metres wide near the mouth of Pearce Gulch Creek. Mineralization in this deposit consists of galena, sphalerite, pyrrhotite and pyrite. A 2.4 metre wide shear zone in quartz sericite schist is reported to contain nodules or lenses of scheelite.
Tungsten mineralization was discovered near the junction of Peter Gulch and Pearce Gulch creeks in the early 1950s. Two adits were driven to test the extent of the tungsten mineralization. To facilitate this exploration several of the remaining Cariboo-Hudson buildings were moved to the junction of Peter Gulch and Pearce Gulch creeks. In 1975, Zelon Chemicals Limited completed geochemical sampling on the Roundtop Mountain area, including Peter Gulch. In 1987, Cathedral Gold Corporation conducted an exploration program over their Cunningham Creek property which covered the Cariboo-Hudson mine and the Peter Gulch showing. The program included property mapping, prospecting, rock and soil sampling, and a magnetometer survey.