The tools hunters made and used during the Archaic Period became increasingly specialized. Lance and spear points, as well as knives, were fashioned by chipping stone with glass-like properties. These tools were tied to wooden shafts in new ways, by using notches and stems. The shape of projectile points was varied for stylistic, and perhaps functional, reasons. Since these innovations were introduced gradually, archaeologists can use the shapes of projectile points as time markers for particular centuries or millennia.