The middens associated with such settlements contain bone, botanical material, mollusc shells, sherds, lithics, and other artifacts and ecofacts associated with the now-vanished inhabitants, and these features, provide a useful source into the diets and habits of Jōmon society.

[2] The Yoshigo Shell Midden dates from the late to final Jōmon period, in an alluvial area with an elevation of six meters above the current sea level, on a gentle slope facing Atsumi Bay.

Many of the skulls showed that front teeth had been removed, confirming a trait of Jōmon culture which has been known from other sites.

The Yoshigo Shell Midden was excavated from 1922 to 1923 and contributed greatly to knowledge of Jōmon anthropology.

In addition, the traces of several pit dwellings were also found in the vicinity, and artifacts such as Jōmon pottery, stone tools and other items have been discovered.