An additional 130 artifacts were found on the surface. In one instance, Harmand's team was able to match a flake to its core, suggesting a hominin had made and discarded the tool at the site.[1] The tools were generally quite large – larger than the oldest known stone tools, recovered in the Gona area of the Afar Region of Ethiopia, in 1992. The largest weighs 15kg, and may have been used as an anvil.[4] According to Harmand, it appeared that the tool makers had purposely selected large, heavy blocks of strong stone, ignoring smaller blocks of the same material found in the area.[3] She ruled out the possibility that the tools were actually natural rock formations, saying "The artifacts were clearly knapped and not the result of accidental fracture of rocks".[2] Analysis suggested the cores had been rotated as flakes were struck off.[2] The purpose of the tools found at Lomekwi 3 is unclear, as animal bones found at the site do not bear any sign of hominin activity.[1] This is the greatest expression of late Neogene technology in human evolutionary history.