Editing Stone tool (section)

===Mode II: The Acheulean Industry===
[[File:Biface (trihedral) Amar Merdeg, Mehran, Ilam, Lower Paleolithic, National Museum of Iran.jpg|thumb|left|upright|A biface (trihedral) from Amar Merdeg, Zagros foothills, Lower Paleolithic, National Museum of Iran]]
[[Image:Hand axe spanish.gif|thumb|upright=1.25|A typical Acheulean handaxe (from the Duero valley in Spain). The small flakes on the edge are from reworking.]]
{{Commons category|Acheulean}}
{{Main|Acheulean Industry}}
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Eventually, more complex Mode 2 tools began to be developed through the [[Acheulean Industry]], named after the site of [[Saint-Acheul (Amiens)|Saint-Acheul]] in France. The Acheulean was characterised not by the core, but by the [[biface]], the most notable form of which was the [[hand axe]].<ref>Clarke's "bifacially flaked hand axes."</ref> The Acheulean first appears in the archaeological record as early as 1.7&nbsp;million years ago in the [[Turkana District|West Turkana]] area of [[Kenya]] and contemporaneously in southern Africa.

The Leakeys, excavators at Olduvai, defined a "Developed Oldowan" Period in which they believed they saw evidence of an overlap in Oldowan and Acheulean. In their species-specific view of the two industries, Oldowan equated to ''H. habilis'' and Acheulean to ''H. erectus''. Developed Oldowan was assigned to ''habilis'' and Acheulean to ''erectus''. Subsequent dates on ''H. erectus'' pushed the fossils back to well before Acheulean tools; that is, ''H. erectus'' must have initially used Mode 1. There was no reason to think, therefore, that Developed Oldowan had to be ''habilis''; it could have been ''erectus''. Opponents of the view divide Developed Oldowan between Oldowan and Acheulean. There is no question, however, that ''habilis'' and ''erectus'' coexisted, as ''habilis'' fossils are found as late as 1.4 million years ago. Meanwhile, African ''H. erectus'' developed Mode 2. In any case a wave of Mode 2 then spread across Eurasia, resulting in use of both there. ''H. erectus'' may not have been the only hominin to leave Africa; European fossils are sometimes associated with ''[[Homo ergaster]]'', a contemporary of ''H. erectus'' in Africa.

In contrast to an Oldowan tool, which is the result of a fortuitous and probably unplanned operation to obtain one sharp edge on a stone, an Acheulean tool is a planned result of a manufacturing process. The manufacturer begins with a blank, either a larger stone or a slab knocked off a larger rock. From this blank he or she removes large flakes, to be used as cores. Standing a core on edge on an anvil stone, he or she hits the exposed edge with centripetal blows of a hard hammer to roughly shape the implement. Then the piece must be worked over again, or retouched, with a soft hammer of wood or bone to produce a tool finely knapped all over consisting of two convex surfaces intersecting in a sharp edge. Such a tool is used for slicing; concussion would destroy the edge and cut the hand.

Some Mode 2 tools are disk-shaped, others ovoid, others leaf-shaped and pointed, and others elongated and pointed at the distal end, with a blunt surface at the proximal end, obviously used for drilling. Mode 2 tools are used for butchering; not being composite (having no haft) they are not very effective killing instruments. The killing must have been done some other way. Mode 2 tools are larger than Oldowan. The blank was ported to serve as an ongoing source of flakes until it was finally retouched as a finished tool itself. Edges were often sharpened by further retouching.