It seems to the writer that much progress has been made in the study of the neolithic age (Jomon Period) in Japan, but the details of the cultural features and changes in each small region have not yet been fully investigated. Accordingly the writer has taken up the Kuriyama Valley as a subject for detailed research and investigation. This Valley, which was a bay thirteen kilometres in length at the beginning of the neolithic age, had been gradually changed into land by the terrestial upheaval and the alluvial accumulation. It has on both banks nearly twenty shell mounds constructed in old and new periods of the Jomon Culture and affords a favourable field for research. The study is still in progress, and the writer has so far obtained the following results.
I. The culture traits of this region. (A) This region is extremely scanty of stone works, (the reason of which has been fully studied and discussed, but we have not yet come to the final conclusion). (B) Judging from the distribution of the earthenware of Shimoono type, it may be said that the culture had been brought along the coast to this region about the middle of the Jomon period. And it is also inferred, from the distribution of the earthenware of Goryoga-dai and Shomyoji type, that the culture had been brought to this region via the Izu and Boso Peninsulas.
II. The food probems (A) In this region few bones of beasts and fish have been discovered. A considerable amount of vegetable must have been taken because the shell fish could not be sufficiently nutritious. People might have eaten the wild plants and it is also probable that they had agriculture of the most primitive stage. (B) This region faces the Pacific Ocean. But, judging from the kinds of the fish bones discovered in this region, fishing was done inside the bay, and not in the open sea. (C) The kind of shell fish varies with the periods : it has been realized that a certain specific kind was selected and supplied in each period. (D) Judging from the positions of the shell mounds and the fact that the shell fish (taken mainly as food) were obtained inside the bay, the writer thinks that the shell fish were gathered just near the shell mounds. Probably the shell gathering was the work for old people, women and children.
III. Chronology and regression As all the shell mounds in this Valley consist of marine mollusca, it is quite probable that the sea extended into the depth of the Valley in the Jomon period. The more secluded the shell mounds are in the Valley, the older they must be, because the sea has turned into what it is by gradual regression. After examining the earthenware of this Valley on this principle, the writer could obtain almost the same chronology of the earthenware as had been established for the shell mounds along the coast of Tokyo Bay. The writer, therefore, believes that the chronology of the Jomon Culture along the coast of Kujukuri has been successfully established. The coas line in the earliest (or proto-) Jomon period seems to have been over the line of ten metres above the sea levels measured today. The height of the coastline in each period has been proved as follows :
Early Jomon period………8～10m.,
Middle Jomon period………8m.,
Late Jomon period………5m.
Then the course of regression has been definitely disclosed, and the writer has succeeded in restoring the prehistoric topography in each period of the Jomon culture.
|
