Bouri Formation
It is located in the Middle Awash Valley, in Ethiopia, East Africa, and is a part of the Afar Depression that has provided rich human fossil sites such as Gona and Hadar.
[1][2][3][4] The area is important because active tectonics in the Afar Depression created varying habitats for early hominins across the most recent few million years known informally as the Plio-Pleistocene.
The Hatayae layer is 40 m thick at its base and is composed of variegated silt clay and paleosols, zeolitic and bentonitic tuffs, carbonates that are pedogenic, sandstone with bivalve and gastropod shells, and mudstone.
"[2] Existence of stone tools is also evidenced by bones of large mammals—such as alcelaphinae (Wildebeest related bovids) and Hipparion, an extinct genus of three-toed horse—that show butchery cut marks by hominins including those made in removing an animal's tongue.
"[2] As concluded by the excavators, the evidence from the site shows "..a major function of the earliest known tools was meat and marrow processing of large carcasses.
The Dakanihylo (Daka) layer is 22 to 45 m thick and composed of pumice sandstone that is cross-bedded; it is situated in the southern half of the Bouri horst and dated to 1 mya.
[4] Early Acheulean stone tools such as hand axes and cleavers have also been found in the Daka member, as well as evidence of butchery processing on equid, bovid and hippo bones.
This layer presents lignite, veins of pink carbonate, and silty clays (of predominantly lake origin) containing gastropod and bivalve fossils; it is dated to 260 thousands of years ago (kya).
As at Herto, Garba III includes terminal Acheulean hand axes, typical Levalloisian method, and many retouched tools on flakes (side-scrapers and end-scrapers, backed knives, burins, unifacial and bifacial points).
[1]In this layer are found a large number of Hippopotamus bones: "One occurrence shows abundant remains of several hippo calves, mostly newborn to a few weeks old, scattered together with butchered adults".
Clark, et al., (2003) reports that "The latter pattern of bone surface modification is almost never present in hominid [hominin] or nonhuman faunal remains processed for consumption, and is therefore unlikely to represent evidence of utilitarian or economic behaviour."
