The boundary of the county follows in great part the river Thames or its tributaries but in many places it is not distinguished from the neighbouring counties by any natural features. On the west the chalk downs run from Wiltshire into Berkshire with no change at the boundary of the county, and on the south there is little distinction between the forest and moorland of Berkshire and of the adjoining tracts of Hampshire and Surrey. Berkshire has thus existed as a county for about 1100 years; previously it was part of the Saxon kingdom of Wessex, which also comprised Hampshire, Wiltshire, Somerset, Dorset, Devon, and part of Cornwall. The Saxons were called in by the Britons to assist them against the Picts and Scots (A.D. 429-449). This was a short time after the departure of the Romans, A.D. 418, or nearly fifteen hundred years ago. The Roman rule in our district may be taken as from A.D. 40 to 418, a period of 378 years. We shall realise the length of their rule if we remember that 378 years ago Henry VIII was reigning in England. When the Romans came to the district they found it occupied by a tribe of Britons named the Atrebates; and Silchester, just over our county boundary in Hampshire, was their chief town or settlement. The written history of the district does not go further back than the Atrebates, but we find many relics of man of a much earlier date. There are in our museums human bones found in old graves, but it is not possible to give them a date or to name the tribe or tribes to which they belonged. There are also early gold coins without any inscription, but bearing a rude figure of a horse not unlike the celebrated white horse cut in the chalk hill above Uffington. These coins take us back to about B.C. 200. There are also various weapons and implements of iron, bronze, and stone, found in graves or barrows or in the beds of our rivers, about which we shall say more in a subsequent chapter. All these remains belong to a period when the surface of the county, though no doubt covered to a great extent with forest, was not very different from what it is to-day. The streams and rivers followed to some extent the same courses and flowed at much the same level as now. But there are remains of man which carry us back to a very much earlier date. In what is known as the Palaeolithic Period our rivers flowed at much higher levels than now; possibly the land has risen since that time, but however that may be, there are beds of gravel of the river Thames as much as 114 feet above the present river, and these gravels contain implements made by man. These, which are at least as old as the gravel in which we find them, are nearly all of flint, and often beautifully made. A large collection from Berkshire is in the Reading Museum. Several animals now extinct were living at that time. The mammoth, the woolly rhinoceros, and the Irish elk roamed through the forest of Berkshire, and in all probability were hunted by Palaeolithic man.