The West Road River placer deposit contains coarse, mainly well worn, nuggety gold. The area is predominantly underlain by alternating bands of argillite and rhyolite.
"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).