EP Gallery: Middle Acheulian -- Olorgesailie, Olduvai Gorge, Near East, Abbevillian (c. 1.0 MYA to 500,000 BP) / i)olgbifdia

Comment: This is Glynn Isaac's "diagram illustrating the concept that the various categories of larger tools [from Olorgesailie] form zones within a field of morphological gradients. The lower diagram shows the frequencies of the major categories in the overall Olorgesailie sample. The percentages are represented as a three-dimensional histogram with the forms distributed essentially as in the upper diagram." This is a key analysis for my own interpretation of Middle Acheulian symbolism. The chart indicates that bifaces are predominantly 'handaxes' (classic cordiform, subclassic, with some irregular ovate and subdiscoid) and 'cleavers' with a high percentage of 'chisel-ended handaxes' that combine features of handaxe and cleaver.

Illustration © Glynn Isaac. Issac, G. [1977]. Olorgesailie: Archeological Studies of a Middle Pleistocene Lake Basin in Kenya. Chicago, University of Chicago Press: figure 40.