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 rocks have been metamorph- osed to greenschist facies and are predominantly metasedimentary.
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 of the Snowshoe Group.
The La Fontaine placer occurs in a gravel, silt and clay-filled former channel of Lightning Creek. Auriferous gravels in this channel occur immediately above bedrock which in this area consists of rocks belonging to the Snowshoe Group.
"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).