 Among the tool types analyzed are projectile points, bifaces, unifaces, ground stone artifacts, and lithic reduction by-products (debitage) such as flakes and cores.Stone is the one category of material which is used by (virtually) all human cultures and, for the vast majority of the human past, is the only record of human behaviour.The end of prehistory does not signify the end of stone working; stones were knapped in Medieval Europe, well into the 19th century in many parts of Europe and the Americas.