It has been known a few of shell mounds on the Early Jomon period so far in the SETO Inland Sea. The majority of those shell mounds are kishima type pottery stages. Tehima Ratazaki shell mounds was followed to shell mounds of the Kishima type stage.
This research introduce the Inujima kitchen midden(S.Ono collection)on the early Jomon period was thought to be a stage immediately before the kishima type. It has been understood that the Inujima shell midden were mainly composed of the Corbicula japonica at the age of about 8600BP and Yamagatamon type potteries.