Averaging about 2 to 4 inches across, they were made using what paleoanthropologists call a «free hand» technique: A core is held in one hand and repeatedly struck with a round hammerstone held in the other hand to release sharp flakes. (discovermagazine.com)
Archaeologists have long considered the advent of the Levallois method of making stone tools — a strategy for obtaining broad, thin, sharp flakes from a chunk of stone called a core — to be a significant development in human prehistory. (scientificamerican.com)
Stone artifacts unearthed in the same sediment as the fossil jaw included chunks of rock from which sharp flakes were pounded off and used as cutting tools. (sciencenews.org)