The Red Cliff showing occurs within an area underlain by Tertiary sedimentary and volcanic rocks resting on older deformed rocks of the Cache Creek Group. The sedimentary rocks consist of sandstone, shale and conglomerate with interbedded tuff horizons, probably of Oligocene age, overlain by Miocene basalt flows. Away from the incision of the Fraser River outcropping bedrock is limited, being largely covered by a mantle of Pleistocene till.

The Oligocene sedimentary rocks of the Fraser River valley include the Fraser River Member, a succession of freshwater sediments containing coal measures. Approximately 1 kilometre south of Quesnel a coal seam of sub-bituminous "B" to "C" rank occurs in the Lower Fraser River Member. The seam, which dips to the north at 5 degrees, averages 60 per cent coal by volume over a thickness of 18 to 30 metres.

Further to the north a coal seam 2 to 6 metres thick has been intersected in drilling. The strata in this area dip at 16 degrees southwest, indicating that the coal measures are folded into a broad syncline about an east-west axis.