even to lower levels when the Pre-Chellean hunters appeared. Since Chellean times all three rivers have silted up their channels. The changes along the Thames which have since occurred are in the superficial layers brought down from the sides of the valley which have softened the contours of the old terraces and have also entombed the later phases of the valley's prehistory. Sections on the south bank at Ilford, Kent, and on the north bank at Gray's Thurrock, Essex, confirm this view. At the latter station, in low-lying strata of brick-earth, loam, and gravel, such as would be formed by the silting up of the bottom of an old river channel, are found the remains of the straight-tusked elephant, broad-nosed rhinoceros, and hippopotamus. All the discoveries of recent years lead to the conclusion that the old fluviatile gravels which contain these ancient mammals and flints are restricted to the lower levels of the Thames valley, while the high level gravels and loams are of later date. Old Chellean flints also occur occasionally on the higher levels, but here it would seem that they have been washed down from the old land surfaces above, because they are found mingled with flints of the late Acheulean and early Mousterian industry. ENGLAND IN EARLY PALÆOLITHIC TIMES It is on the higher levels of the Thames, as of the Somme, and in the superficial deposits covering the sides of the valley that we read the story of the subsequent Palæolithic cultures and of an early warm temperate climate being followed by a cold climate with frozen subsoil belonging to the fourth glaciation and the contemporary Mousterian flint industry. The Palæolithic history of the Thames(30) has not yet been fully interpreted, but it would appear that the relics of the old stations of Kent and Norfolk will yield all the forms of Chellean and Acheulean implements, and probably also those of the Mousterian which have been discovered in the valley of the Somme, thus proving that the Lower Palæolithic races of this region pursued the same culture development as the neighboring tribes of France and Belgium, as well as those of Spain, up to the close of middle Acheulean times. A similar sequence of events appears to be indicated at Hoxne, Suffolk, where archaic palæoliths were discovered as far back as 1797. This discovery was neglected for upward of sixty years, until in 1859 these flints were re-examined by Prestwich and Evans after their visit to the stations of the Somme (Geikie,(31) Avebury(32)). This site was in the hollow of a surface of boulder-clay, overlain by the deposit of a fresh-water stream; in the bed of its narrow channel, besides flint implements of early Acheulean type, abundant plant remains were found which give us an interesting vision of the flora of the time.