Abstract: In 2007, over ten thousand cracked stone pieces were unearthed during a test excavation from a thick ashy layer at Locality 12 of the Shuidonggou Paleolithic site in the Ningxia Hui Autonomous Region, North China. The cultural horizon yielding such fractured stone was dated to 11000 —12000 BP by AMS and OSL methods. Morphological observations and lithological analysis of the broken stones indicated that they were the result of ancient human selection, transport, heating , and utilization. Experimental studies on similar lithic materials support the idea that such cracked pieces went through the process of repeated heating and water immersion. Therefore, it is presumed that these pieces were “cook stones” used by ancient humans to aid in the cooking of foods and boiling of water. Chemical tests on water samples collected from ground and underground sources near the site indicate a high intestinal Bacillus content, and thus natural water could not have been utilized directly without heat treatment. Paleoenvironmental studies point out that during the late Upper Pleistocene, many kinds of plant food resources were available to human groups living in the region, and that some of such plant foods, especially seeds, would be edible to humans only after being boiled or cooked. It is the first time that evidence of complex and an indirect way of fire use, i.e., hot-rock cookery, has been recognized from Paleolithic remains in China, and thus, such boiling stones provide valuable information for studying ancient human adaptative strategies and the development of human fire-use history.

Key words: Burnt stones; Hot-rock cookery; Shuidonggou Locality 12; Late Upper Pleistocene