野尻湖立が鼻遺跡第１０次発掘出土の骨器

Abstract

The first excavation at Tategahana, on the shore of Lake Nojiri, was carried out in 1962; since then, excavations have been undertaken ten times. On the occasion of the 10th excavation season in 1987, the total number of excavated items reached 7, 872. They include 755 archaeological items, 1, 931 mammalian fossil items, 98 lithic artifacts and 23 bone artifacts which were mainly made of bones of the Naumann elephant (Palaeoloxodon naumanni).The Nojiri-ko Formation is divided into three members, Lower, Middle and Upper, with marked unconformities between them. Furthermore, each member is subdivided into three or four parts. On the basis of radiocarbon dating and both palaeontological and archaeological studies, the chronometric framework of the Nojiri-ko Formation can be attributed as follows: the Lower Member represents 50, 000-30, 000y.B.P., the Middle Member represents 30, 000-25, 000y.B.P., and the Upper Member represents 25, 000-10, 000y.B.P.The present paper focuses on bone tools including a cleaver, flakes, a spiral flake and chips made of Naumann elephant bones from Middle Member I (26, 100±2, 070y.B.P. 14C, GaK-7789), giving a description of morphological characteristics and attempting to reconstruct the manufacturing processes of bone tools. The most remarkable tool from this layer is a bone cleaver which coincides well morpho-typologically with the definition of a stone cleaver. Our discussion compares the cleaver with other examples of bone cleavers from Anaguni, Central Italy, and Lang/Ferguson, South Dakota. The characteristics of secondary flaking technique for the bone cleaver, together with a bone “point” excavated in the 5th excavation season, were discussed in comparison with the flaking technique expressed among lithic industries from Cultural Layers IX and X in the Musashino Upland area of Tokyo.The distribution pattern of the bone tool assemblage, including two refitted bone items, on the horizon of Middle Nojiri-ko Member I implies that the elephant hunters had also made bone tools in the process of kill-butchering.