Thus it would appear that, in regard to the river courses and the hills through which they flowed, the topography and landscape of northern France and of southern Britain were everywhere the same as at the present time. The forests which clothed the hills were not greatly different from the present, except for the presence of a few trees of a warmer clime, nor was there anything strange or unfamiliar in the majority of the animals that roamed through forest and meadow. The three chief archaic elements consisted in the presence of two very ancient races of men and their rude stage of culture, in the great forms of Asiatic and African life which mingled with the more familiar native types, and in the broad, continuous land surfaces which swept off unbroken to the west and southwest.
For in those days Europe, though even then little more than a great peninsula, extended far beyond its present limits. England and Ireland were still part of the mainland, and great rivers flowed through the broad valleys that are now the Irish Sea, the North Sea, and the English Channel—rivers that counted the Seine, the Thames, the Garonne, and even the Rhine, as mere tributaries. The Strait of Gibraltar was then the Isthmus of Gibraltar—a narrow land bridge connecting Europe with Africa. The Mediterranean was then an inland lake, or rather two inland lakes, for Italy and Sicily stretched out in a broad, irregular mass to join the northern coast of Africa, while Corsica and Sardinia formed a long peninsula extending from the Italian mainland and almost, if not quite, reaching to the African coast.
The Thames Valley in Chellean Times
The interpretation of the features of stratification in the valley of the Somme is especially interesting because it gives us a key to the understanding of a similar sequence of prehistoric events in the valley of the Thames.
The station of Gray's Thurrock in this valley is barely 120 miles distant from the Chellean station of Abbeville, in the valley of the Somme, and it is apparent that the old flint workers were freely passing across the broad intervening country and interchanging their ideas and inventions. Thus it happened that Chellean implements identical with, or closely related to, the types of the Somme valley were being fashioned all over southern Britain from the Thames to the Ouse. The ancient River Thames (Lyell,[(28)] Geikie[(29)]) was then flowing over a bed of boulder-clays which had been deposited during the preceding glaciations. Its broad, swift stream was bringing down great deposits of ochreous gravels and of sands interstratified with loams and clays. It is these old true river-gravels which display their greatest thickness on the lowest levels of the Thames and which are largely made up of well-bedded and distinctly water-worn materials. On these low levels the flint workers sought their materials, and here they left behind them the archaic Chellean implements which are now found embedded in these older river-gravels, just as they occur in the gravels washed down over the three terraces of the Somme and the Marne. In the Thames this old gravel wash seems to have been down-stream, whereas on the middle and upper terraces of the Somme the gravel wash came directly down the sides of the valley, except, perhaps, in very high floods. These deep beds of gravel, sand, and loam lie for the most part above the present overflow plain of the Thames, although in some places they descend below it; which proves that the main landscape of the Thames also, except for the changes of the flora and of animal life, was the same in Pre-Chellean and Chellean times as it is at present. Thus the Somme, the Thames, and the Seine had all worn their channels to the present or 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.