At www.pasthorizonspr.com/index.php/archives/05/2013/origins-of-chinese-agr… ..the first evidence of agriculture, the domestication of plants and animals, is dated to the early Holocene – around 10,000 years ago. However, such skills were probably not learnt overnight, so to speak, and scientists have been able to trace tools used to grind seeds back to 23,000 years ago – so far. The same kind of tools were being used to process seeds and tubers in northern China at the same time as grinding was a fact of life in western Asia. Grinding stones are found in Upper Palaeolithic archaeological sites around the world and consist of two stones. One was held in the hand and was used to rub against a larger flat stone set on the ground, designed to process seeds, roots and tubers into flour. The residue of starch grains on the surface of such stones can be used to analyse the types of plants being processed. In China they were grinding wild millet seeds, for example, and this became the staple crop of the Chinese neolithic.