As the distinctive characteristics of the sub-order, and also of the single existing genus Elephas, are given in the article Proboscidea, it will suffice to point out how the two existing species are distinguished from one another.
The Quaternary period includes an older stage containing fragments of fossils from the underlying formations; a later stage containing the bones of Hippopotamus, Elephas, Rhinoceros, Camelus, Equus; and finally the vast accumulations of sand which began to be formed in prehistoric times.
This view may receive some support from the occurrence of a dwarf form of the African elephant in the Congo; and if we regard the latter as a subspecies of Elephas africanus, it seems highly probable that a similar position will have to be assigned to the pigmy European fossil elephants.