Plant microfossils have been recovered from Oligocene sediments which outcrop along the Fraser River in the central interior of British Columbia, Canada. The sediments are composed of interbedded clays, sands, gravels, and lignites which were deposited as a part of an ancestral Fraser River system.The most commonly encountered members of the assemblage areQuercus, Alnus Carya, Liquidambar, Ulmus/Zelkova, Juglans, Pterocarya, Osmunda, and members of the Taxodiaceae, with infrequent occurrences ofEngelhardtia, Prosopis, ?Psilotum, Ephedra, and ?Dorstenia. This assemblage suggests a warm temperate to near subtropical climate. A warm polar sea, a lowered Coast Range to the west, and a greater elevation of the Rockies to the east are suggested as a possible explanation for the climate.One new genus and 11 new species have been erected. Several species, includingProsopis quesneli, Diervilla echinata, Triporate B, andTaxodium rouseiappear to be restricted to these beds, and may well be good index fossils for the Oligocene of western Canada.