Page:Early Man in Britain and His Place in the Tertiary Period.djvu/45

]

We may gather from the alternation and repetition of beds deposited by fresh, brackish, and salt water, in the above table, the important fact that south-eastern England was traversed by a fluctuating shore during the whole of the Eocene age, while to the north-west of the line above mentioned there were no geographical changes sufficiently great to leave any permanent mark in the geological record. On the continent, however, great oscillations of level took place. The Pre-nummulitic age was a period of elevation, followed in the Nummulitic by a great depression beneath the waves of the sea, followed in its turn by a period of re-elevation. None of these movements have left any trace in Britain, in the area to the north-west of the above-mentioned line, consequently this may be taken to be that of the Eocene sea-board of Britain. Its exact position varied from time to time, and considerable additions were made to the land, more particularly in the Post-nummulitic times, by the accumulation of shoals and alluvia, like those by which large tracts have been added to Great Britain since the invasion of the Romans, such as that joining the Isle of Sheppey to the mainland of Kent, or that which has converted the Roman port of Anderida into the green pastures running close under the ramparts of Pevensey Castle. By this means, as well as by movements of elevation and depression, frequent changes took place in the shallow Eocene sea.

We have no evidence that the Eocene sea touched