The morphological identification of micro-residues on stone tools using light microscopy: progress and difficulties based on blind tests

Fifty-three stone flakes were knapped for a series of four blind tests on replicated flakes with residues derived from the processing of plant and animal products. Some flakes were hafted before use. Tests 1 and 2 were pioneering efforts published in 2004; lessons learned from these early studies shaped the new research reported here and lead to improved methodology and interpretive skills. A high level of accuracy was obtained for test 4. Test 3 showed that the rock type of a tool could influence the ability of the analyst to recognize and interpret residues. Test 4 in the series resulted in the most accurate interpretations because, prior to Test 4, identification difficulties experienced during the first three blind test sessions were addressed by examining many stone tools that had been used for various replicated tasks. The preparatory exercise was particularly useful for resolving issues that had previously caused problems for correctly identifying animal residues. The new work reported here highlights some of the difficulties that can be experienced in the morphological identification of microscopic organic residues, particularly the distinction between animal and plant residues. Some solutions for these problems are suggested.