Early Acheulian & Developed OldowanB / r)oldef-hrbiffig64
Lava biface made from an end-struck flake. Site EF-HR, Upper Middle Bed II, Olduvai Gorge (c. 1.3 MYA).
Perhaps classifiable as a one-tiered, four-faceted symmetry, with naturally rectilinear sides and a naturally pointed top and trimmed rounded bottom.
Photo © Leakey, M. (1971). Olduvai Gorge, Vol. 3. Cambridge: At the University Press: fig. 64. (yellow highlight added)