The earliest known evidence of human activity in what is now Salford is provided by the Neolithic flint arrow-heads and workings discovered on Kersal Moor and the River Irwell, suggesting that the area was inhabited 7–10,000 years ago. The raw material for such tools was scarce and unsuitable for working, and as a result they are not of the quality found elsewhere. Other finds include a neolithic axe-hammer found near Mode Wheel, during the excavation of the Manchester Ship Canal in 1890, and a Bronze Age cremation urn during the construction of a road on the Broughton Hall estate in 1873.