Placer gold deposits of the Quesnel Highland region, including the former rich producers of the Barkerville Camp, have accounted for a large proportion of British Columbia's alluvial gold production. With the exception of a few producers in the Wingdam area, which are underlain by Upper Triassic sediments correlative with the Nicola Group, almost all the deposits are underlain by the Upper Proterozoic to Lower Paleozoic Snowshoe Group. These predominantly metasedimentary rocks have been metamorphosed to greenschist facies.

Placer gold deposits in the region are generally found in relatively young Pleistocene gravels. The morphology and mineral associations of the gold suggests that it was derived locally, the most obvious sources are the numerous auriferous veins in the Downey succession (quartzite, phyllite) of the Snowshoe Group.

Placer gold mining operations have taken place on California Gulch. In the early days the main mining was near the mouth of the creek. Intermittent gold production from 1906-10, 1926-30 and 1931-35 totalled 4229 grams (136 ounces).

"Data from the Cariboo mining district indicate that supergene leaching of gold dispersed within massive sulphides by Tertiary deep weathering followed by Cenozoic erosion is the most likely explanation for the occurrence of coarse gold nuggets in Quaternary sediments" (Exploration in British Columbia 1989, page 147).