野川先土器時代遺跡の研究

抄録

A. The Nogawa Site and its Stone Culture (KOBAYASHI and ODA)
1. The Nogawa site is located in Kamiishihara, Chofu City, Tokyo. It sits on a low bluff on the Tachikawa Terrace facing across a stream toward the higher Musashino Terrace marked by the Kokubunji Cliff Line (fig. 1).
2. The site was first excavated in 1964, and exploratory excavations were carried on for the next several years (Kidder et al.: 1970). Then a project to widen the stream threatened to destroy the site, and in response the Nogawa Site Excavation Group was formed to excavate the endangered part of the site. Excavations were carried out from June to the end of August 1970 (Nogawa Iseki Chosa Kai: 1970, 1971a, 1971b, 1971c).
3. Geologically the site has thirteen strata (fig. 3). The base stratum XIII is gravel. Over this are nine layers of loam, strata IV to XII, the so-called Tachikawa loam. Four of these strata, strata IVb, V, VII and IX, are black bands of fossil soils. Stratum III is the soft loam, stratum II is a brown humus, and stratum I is a black humus.
4. Culturally there are eleven layers, ten Preceramic Period layers (numbered III, IV1, IV2, IV3a, IV3b, IV4, V, VI, VII and VIII to correspond to the geological strata in which they were found) and one mixed Jomon Period layer in stratum II. More than 10, 000 artifacts were recovered from the Preceramic Period layers. Over 2, 000 are tools or flakes. Another more than 7, 000 artifacts are fire-reddened gravel usually found in heaps. The clarity of stratification, the number of layers, and the quantity of artifacts make Nogawa the best stratified, Preceramic Period site in Japan.
5. The Nogawa data, when correlated with data from other sites in Kanto (fig. 7-10) (in particular, the Heidaizaka Site and ICU Location 15 in Koganei City and the Tsukimino Site Group on the Sagami Terrace in Kanagawa Prefecture), allows definition of four broadly defined phases for the Preceramic Period. The earliest phase, Nogawa layers VIII to V (Heidaizaka layers X to V), has mostly flake tools plus some heavy-duty tools made from pebbles. Phase II, Nogawa layers IV4 to IV1, is characterized by backed blades. Temporally related changes in the form of these backed blade tools are apparent. The early assemblages of the phase are marked by lightly worked blades of knife-like form. Later assemblages see changes to smaller tools of more geometric form and the appearance of small, bifacially worked points. (Phase III of the South Kanto Preceramic Period is distinguished by the presence of microblades and the cores from which they were obtained. However, this phase is not represented at the Nogawa site). The latest Preceramic Period phase, phase IV, Nogawa layer III, consists mainly in large, biface points and pebble tools.
6. The heaps of fire-reddened gravel are found mostly in Nogawa layers IV1 to IV4, i. e. Preceramic Period phase II. X-ray diffraction analysis done by M. Suzuki of Tokyo University shows the stones to have been heated to more than 600°C. The meaning of these heaps is unclear. It is not known whether they were used as found-single layers of gravel spread in near circular patterns one to two meters in diameter-or whether they were simply disposed of at a location in the site some distance from where they were used. However, many of the stones do have a kind of tar-like substance on them, and one is probably justified in thinking the stones were used directly in some manner for cooking. Also, pounding stones, grinding stones and anvil-like stones are frequently found in close proximity to the heaps.