Five genera of Proboscidea have been discovered in Early Miocene and basal Middle Miocene sediments of the lower Orange River Valley. Deinotherium, Eozygodon, Progomphotherium (nov. gen.) and Gomphotherium, occur at Auchas in the proto-Orange terrace aged about 19-20 Ma, while Deinotherium and Afromastodon (nov. gen.) occur at Arrisdrift in proto-Orange deposits aged about 17.5 Ma.