Kakumazaki Shell Mound and Hachirogata lagoon in the Jomon Period
The Kakumazaki Shell Mound, located near the western shore of Ogata Village, is an archaeological site dating primarily to the Early Jomon period (around 6,000 years ago).
Shell mounds containing many marine shells are rare in Akita Prefecture, but at Kakumazaki, 17 out of 20 species found were marine shells.
Mr. Nishimura, who studied the shells from Kakumazaki, classified the marine shells into three groups based on their habitat: those from rocky shores, from sandy beaches facing the open ocean, and from inner bays. He suggested that the shells from inner bays were likely collected from the “Hachirogata” area, which, at that time, was a sea and formed a bay.
This hypothesis was proposed in the early 1930s.
Later, in the early 1950s, many shells from around 6,000 years ago were discovered in layers of soil beneath Ogata Village, including almost all the types of inner-bay shells found at Kakumazaki.
This discovery confirmed that one of the places where the people of Kakumazaki gathered shells was indeed the “Hachirogata” area.
Before land reclamation, Hachirogata was a treasure trove of marine resources, and it appears that it was also a bountiful sea for the people of the Jomon period.
