Oobora Shell Mound

A shell mound from the late Jomon period is located in Ohora, Akasaki-cho, Ofunato City, Iwate Prefecture. It is one of the shell mounds on the hills of Ofunato Bay, on a gentle hill sandwiched between two valleys a little way in from the east coast of the bay. The shell mounds are formed on the northern and southern slopes of the hill, and the shell mound on the cliff on the western side of the northern slope is called Area A, the one below the cliff is called Area A', the shell mound on the eastern side of the northern slope is called Area B, and the shell mound on the southern slope a little further away is called Area C. Shell mounds have been excavated for a long time, and in 1925 (Taisho 14), Hasebe Kotondo and Yamauchi Sugao conducted an investigation of the shell mounds in each of the above areas. Based on the excavated materials, Yamauchi Sugao subdivided the shell mounds into six types: Ohora Type B, BC, _C1 , _C2 , A, and A', and arranged them chronologically in that order. This chronological system is used as the chronological standard for late pottery. In addition to pottery, stone tools, bone and horn tools, and shell rings have also been excavated. The shell mound mainly contains clams, fish bones such as sharks and tuna, and animal bones such as deer and wild boar. It was designated as a prefectural historic site in 1966 (Showa 41).

[Kusama Shunichi]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

岩手県大船渡(おおふなと)市赤崎町大洞にある縄文時代晩期の貝塚。大船渡湾岸の丘陵にある諸貝塚の一つで、湾の東岸より少し入った谷に挟まれたなだらかな丘陵にある。貝塚は丘陵の北斜面と南斜面に形成されているが、北斜面西側の崖(がけ)の上の貝塚をA地区、崖下をA′地区、北斜面東側の貝塚をB地区、これから少し離れた南斜面の貝塚をC地区とよんでいる。貝塚は古くから発掘調査が行われているが、1925年（大正14）に長谷部言人(はせべことんど)と山内清男(やまのうちすがお)とによって上記各地区の貝塚の調査が行われた。その出土資料等に基づいて、山内清男は大洞B式、BC式、C₁式、C₂式、A式、A′式の6型式に細分し、その順序に編年序列を行った。この編年型式が晩期の土器の編年基準として用いられている。土器のほか、石器、骨角器、貝輪なども出土している。貝塚はアサリを主とし、サメ、マグロなどの魚骨や、獣骨ではシカ、イノシシが多い。1966年（昭和41）県指定史跡となっている。

［草間俊一］

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