within the Albertine Rift of the African rift valley.

The earliest work in the region was on exploratory expeditions in 1877 and 1878, with fossils collected in the areas of Nine-Mile Creek, Vermilian Bluffs on the Similkameen River, and Whipsaw Creek. While reporting on additional plant fossils collected from British Columbia, Penhallow (1906) noted the likely coeval status