The Mesolithic period, meaning Middle Stone Age, dates from the end of the last Ice Age, around 10,000 BC. It is a period where people could move around more easily because the ice sheets that had covered large areas of Europe and Britain were receding. In the early Mesolithic, Britain was still linked to the continent by a land bridge, but as the ice sheets melted, the sea rose and isolated these islands by 6000 BC.
People were mobile in the Mesolithic period and followed herds of animals to hunt them. Food was also gathered, a particular favourite seems to have been hazelnut shells. Fish and shellfish also seem to be important in the Mesolithic period. In Europe, particularly in Scandinavia, there are large Mesolithic shell middens, or rubbish dumps, attesting to high consumption of seafood.
Mesolithic people seem to have returned to certain places seasonally, or perhaps less frequently than once a year. River or lake-side settlements are most common and include some lake-villages in Denmark and Germany. The most famous Mesolithic site in Britain is Star Carr in Yorkshire. This was a lake-side site dating to the Early Mesolithic, radiocarbon dated to 8700 BC, that was probably visited regularly over a few hundred years. It may have been a place to butcher hunted animals or for manufacturing stone tools. More recent work has shown that there are a number of Mesolithic sites around the same lake.
In Buckinghamshire, Mesolithic flint tools are often single finds from the topsoil, especially on ploughed fields, or are found as a background scatter in later artefact assemblages. However, there are a small number of Mesolithic occupation sites in Buckinghamshire, mainly on river-banks. Recent excavations in Denham at the Sanderson factory site next to the River Colne revealed another scatter of flint flakes and tools on the leeward side of a hearth. There were piles of red deer bones and hazelnut shells, defining zones where the two were processed. A silted up former channel of the River Colne passed close by to the site. More early Mesolithic artefacts were found under the Sanderson's playing fields at Boyer's Pit. This site is also very close to the well-known Mesolithic and Neolithic occupation site at Three Ways Wharf in Uxbridge, just outside the county boundary.
Two excavations in Chesham in the 1960s and 1970s at Stratford's Yard and East Street close to the River Chess uncovered a layer of soil in which Late Mesolithic flint tools, animal bones and hazelnut shells were deposited. Sometimes it is hard to distinguish between Late Mesolithic and Early Neolithic flint tools, as they are very similar. This is the case at Latimer Park Farm where another flint scatter has been uncovered. Another Late Mesolithic site was found near Fawley Court next to the River Thames. Many Mesolithic artefacts have come from the Thames itself, perhaps eroding out of river-side settlement but probably also deliberately thrown in the river, such as the perforated antlers found near Taplow.
The Mesolithic period ends around 4500 to 4000 BC, as the transition between the Mesolithic and Neolithic is not well understood. The Neolithic period is a time when some agricultural techniques start being used to control food resources, and when monumental constructions are built.