About 45,000 years ago, some stoneworkers developed a new technology based on preparing cylindrical cores from which long, parallel-sided blades were removed by indirect percussion with a punch and hammerstone (see Figure 11.6). These regular blanks were then trimmed into knives, scraping tools, and other specialized artifacts (see Figure 11.7 on page 196). This blade technology was so successful that it spread all over the world. It has been shown to be highly efficient (see Doing Archaeology Box). Controlled experiments resulted in 6 percent of the raw material being left on one exhausted blade core; 91 percent of it formed 83 usable blades. Once blades had been

removed from their cores, they were trimmed into shape by a variety of techniques. In some, the blade’s side was pressure-flaked with an antler or a piece of wood to sharpen or blunt it. Sometimes the flake would be pressed against another stone, a bone, or a piece of wood to produce a steep, stepped edge or a notch (see Figure 11.7a and b).