Basin and its London clay bedrock. The low-lying flood plains to the west consist of fluvial gravels, sands and clay. To the east, within Richmond Park, a more erosion-resistant fluvio-glacial deposit of gravels laid down in the interglacial period between 240,000 and 400,000 years ago forms the escarpment ridge that runs north–south between the Richmond and Kingston hills. Toponymy The name derives from the Old English word Hamme meaning "place in the bend of a river". Archaeology The Thames Valley has been inhabited since the Palaeolithic period and finds of Palaeolithic flints near White Lodge, Richmond Park show that Ham was part of early human territory. Later, Mesolithic, flints found at Ham dip, Dann's Pond and Pen Ponds within the park are also evidence of early habitation as are Neolithic barrows on the ridge of the hill overlooking Petersham, Ham and Kingston. These have not been excavated, so it is impossible to date them precisely, but barrows are known to span the period from 3500BC to 900BC. Several surface finds of flint tools, axes, adzes, scrapers, awls chisels and knives as well as arrowheads, hammer stones and flint shards were made during gravel workings in Ham Fields at Coldharbour, near the present day Thames Young Mariners site () and further east in maize fields now covered by housing. These finds are made from high quality flint from the North Downs rather than local river-borne flints from the Thames Valley, implying human transportation and a settled rather than nomadic lifestyle in the area. Many of these artifacts are part of the Edwards Collection and housed in the Museum of Richmond. Other finds from Ham are held at the Museum of London including an early Bronze Age collared urn, also from the Edwards Collection. A few finds of Romano-British pottery from the late Iron Age, mid 1st and early 2nd centuries AD show that the area remained inhabited to some extent, though the closest indications of modest Roman settlements are further south in the Canbury area of North Kingston. The first early Saxon settlement found in the Greater London area was a pit-house, or , excavated at Ham in the early 1950s. Along with pottery finds dated to the 5th century AD, this suggests the area was amongst the first colonised by Saxon settlers. History Ham does not appear in Domesday Book of 1086, the nearest entries being Petersham to the north