The McBride showing is located near McBride on the Fraser River. This area is underlain by platformal sedimentary rocks of the Cariboo Terrane. These rocks comprise conglomerate, shale and quartzite of the Lower Paleozoic McNaughton Formation which, in the Fraser River Valley, are poorly exposed.

The showing comprises fluvial concentrates of black sand in which radioactivity, likely attributable to thorium, has been detected. The source of the radioactive sand may be gneissic rocks of the Omineca Belt to the southwest.

"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).