Even toward the close of the Third Interglacial Stage there were periods of warmth, perhaps during the height of the hot summer season, when animals of the warm fauna migrated from the south. Thus Commont has recently discovered in the valley of the Somme a station of Mousterian flint workers, whose industry is associated with remains of the three animals typical of the warmer climatic phase; namely, the straight-tusked elephant, the broad-nosed rhinoceros, and the hippopotamus. He has reaffirmed his belief that the greater part of this chapter of human prehistory, both as to the surface topography of the Somme valley and the evolution of the flint cultures from Pre-Chellean to Mousterian times, occurred during the Third Interglacial Stage. THE EARLY WARM TEMPERATE PERIOD OF THE PRE-CHELLEAN CULTURE[V] We have observed that from Torralba in the Province of Soria, Spain, to Abbeville, near the mouth of the Somme, in the north of France, three types of animals which entered Europe as early as Upper Pliocene times, namely, the Etruscan rhinoceros, the horse of Steno, and the sabre-tooth tiger, are said to occur in connection with early Chellean artifacts. The two former species may possibly be confused with early forms of Merck's rhinoceros and the true forest horses of Europe, but there can be no question as to the identification of the sabre-tooth tiger, numbers of which were found by M. d'Ault du Mesnil, at Abbeville, on the Somme, with early Chellean flints. PRE-CHELLEAN FAUNA Southern mammoth. Etruscan rhinoceros. Hippopotamus. Primitive horse (_Equus stenonis_)? Sabre-tooth tiger. Broad-nosed rhinoceros. Straight-tusked elephant. Giant beaver (_Trogontherium cuvieri_). Short-faced hyæna. Typical Eurasiatic forest and meadow fauna, including deer, bison, and wild cattle. The mammalian life of the Somme at this time, as found in the _gisement du Champ de Mars_ near Abbeville, is very rich. Among the larger forms there is certainly the great southern mammoth (_E. meridionalis trogontherii_), and possibly also the straight-tusked elephant (_E. antiquus_). There are unquestionably two species of rhinoceros, the smaller of which is recognized by Boule as the Etruscan, and the larger as Merck's rhinoceros. Steno's horse is said to occur here, and there are abundant remains of the great hippopotamus (_H. major_); the sabre-tooth tigers were very numerous as attested by the discovery of the lower jaws of thirty or more individuals. The short-faced hyæna (_H. brevirostris_) is also found, and there are several species of deer and wild cattle. This remarkably rich collection of mammals is associated with flints of primitive Chellean or, possibly, of Pre-Chellean type.(12) In Torralba, Spain, the same very ancient animals occur, and it appears possible that this was the prevailing mammalian life of Pre-Chellean times.