The Isimila Acheulian Occupation Site in the Iringa Highlands of Tanzania was discovered in 1951 by D.A Marclennanof who on his way from Nairobi to Johannesburg collected some tools from the site. A first scientific report by Clarence van Riet Lowe, at that time the most eminent Prehistorian of South Africa, appeared already in 1951. The first Excavation work at Isimila was carried out 1957-1958 by Clark Howell, later followed by others until 1968. The Acheulian at Isimila, has been dated by U-series to ca. 260 k.a. (Howell et al., 1972), but is now suggested to be older than 300 k.a. A new project started this year to re-examine the stratigraphy and age with more advanced techniques (
http://blogs.brighton.ac.uk/geography/2014/09/). The site is in a short distance from Iringa town and is one of the richest finds of Paleolithic tools anywhere in the world. Nowadays the site is a Museum and is reached by a hike through amazing eroded columns in nearby dry river gorge (http://nathan-palmer-royston.tumblr.com/post/27717075060/isimilia-stone-age-site-it-is-estimated-that-it.)
Made in the Acheulian tool-making “tradition”, this handaxe is 20 cm long. Although it is oversized in comparison with most European stone tools of the same type, it was not unusually large for the site at Isimila where it was found, nor for similar tools found at other East African sites. One reason for its large size is the nature of material of which it is made. Large blocks of rock (basalt, rhyolites, trachytes, phonolites, and other lavas) that were commonly available for use in many regions of East Africa during the ESA/MSA, yield large flakes which can be worked into large cutting tools. The flint nodules used by prehistoric Europeans are often smaller. On the other hand, in East Africa during the Acheulian, quartz and chert-often in the form of erratics from stream channels served for the manufacture of Light Duty equipment.
Howell showed that the massive quantities of large cutting tools that greet the observer at some localities are lag deposits that have accumulated through the erosion of many superimposed occupation levels. However, many other intact occurrences do indeed contain impressive numbers of bifaces, as discoveries at the east African Middle Pleistocene sites like Olorgesaille, Isenya, Kariandusi, Lewa and Melka Kunture, amply demonstrate. Mary Leakey distinguished between the Acheulian and the Developed Oldowan at Olduvai Gorge upon the basis not only of technical features of the bifaces, but also upon biface frequency, requiring that 50 per cent of the tools in an assemblage be handaxes and cleavers for it to qualify as Acheulian. Many authors would now argue that the presence of even a single handaxe in an assemblage renders it Acheulian.
Experimental investigation clearly shows that “large cutting tools” (handaxes and cleavers) are well suited for the task of carcass dismemberment and defleshing, but artifact associations do not unequivocally support the early assumption that they were butchery implements. On the one hand, association of bifaces with megafaunal remains at Torralba and Ambrona, Spain, for example, does support their use in butchery, as do artifact association, refitting, and microwear at Boxgrove, England. On the other hand, many Middle Pleistocene single carcass occurrences that appear to represent butchery episodes have few handaxes or lack bifaces altogether. These include the Elephas recki skeletons from Member 1 at Olorgesaille, Kenya , and from FLKN at in Bed I at Olduvai Gorge, Tanzania, and the partially dismembered elephant from the contact between the Chiwondo and Chitimwe Formations at Mwanganda, Malawi . Partially dismembered Hippopotamus skeletons have been discovered in the Lukingi Member at Isimila, Tanzania, and from Gadeb 8F, Ethiopia. The artifact assemblages in all these occurrences are made up primarily of small flakes, cores, and scrapers, with the addition of rare bifaces or heavy duty implements. No doubt the handaxe, a long-lived and geographically widespread implement, served a variety of purposes in the many different contexts in which it was used. No microwear has yet been detected on east African handaxes, most of which are made of lava. But studies of usewear on handaxes found elsewhere serve to confirm the impression that the handaxe was a multipurpose implement.
Some similar Handaxes from the same site (Howell 1972):