This article is about the history of Nottingham. Pre-history The middle Trent Valley was covered by ice sheets for large parts of the Paleolithic period between 500,000 and 10,000 years ago, and evidence of early human activity is limited to a small number of discarded stone artefacts found in glacial outwash or boulder clays. The post-glacial warming of the climate in the Mesolithic period between 10,000BC and 4,000BC saw the Trent Valley colonised by hunter-gatherers taking advantage of the emerging mixed woodland environment. Flintwork dating from the period has been excavated on the site of Nottingham Castle, and stone tools used by hunter-gatherers have been found in areas of the city including Beeston, Wollaton Park and the site of the Victoria Centre. The Neolithic period between 4,000BC and 2,000BC saw the clearance of woodland and the transition of the area towards a settled agricultural society. Pottery from the period has been found in Attenborough and Holme Pierrepont, and Neolithic stone axes have been found in the city manufactured as far away as Great Langdale in the Lake District and Penmaenmawr in North Wales. Holme Pierrepont is also the site of the area's most impressive Stone Age monument: an early Neolithic burial monument consisting of several intercutting concentric ditches surrounding a central mound containing five shallow pits. Abundant evidence exists of Bronze Age habitation in the area, including tools and weapons found in the River Trent and other local rivers, a flat axe found in Edwalton and a looped palstave found in Bestwood. A large hoard of Bronze Age metalwork was discovered during building works in Great Freeman Street in 1860, dating from the late 9th or 8th centuries BC and consisting of ten socketed axes, four bronze arrowheads, a palstave, a hollow ring and the base of a spear shaft. A possible Bronze Age dwelling has been discovered in Clifton, including a series of oak stakes spaced about a yard apart in the river bed of the Trent and a collection of mid and late Bronze Age metalwork including spearheads, rapiers, swords, knives and a dirk. Similar though less well preserved sites have been discovered in Attenborough and Holme Pierrepont. Cropmarks indicating the ring ditches of Bronze Age burial sites are densely distributed across the gravel terraces around the Trent in the south of the city. Excavation of these sites have revealed evidence of cremations and traces of Bronze Age