Chimpanzee Stone Age

The following paper, published in 2007, contains clear photos of ancient starch granules. It can be seen on the net (PDF).

• Mercader, Julio, Huw Barton, Jason Gillespie, Jack Harris, Steven Kuhn, Robert Tyler, and Christophe Boesch. 2007. 4,300-Year-old chimpanzee sites and the origins of percussive stone technology. Proceedings of the National Academy of Science (PNAS) 104 (9): 3043-3048.