A flat and heavy cutting tool of stone, metal or shell in which the plane of the blade is at right angles to the haft. Where the method of hafting is not obvious, the adze is distinguished from the axe by its asymmetric cross-section. It may be used for tree felling, but its main purpose, before the introduction of an efficient saw, was for trimming timbers. It would have been particularly useful for jobs such as hollowing out a dugout canoe. Most of the adzes found in Buckinghamshire date to the Neolithic period, such as the ones found at Holmer Green, Coombe Hill or in the Thames near Maidenhead.