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.

The location of this shell midden is on a plateau at the foot of Mount Ganjoji, to the northwest of the city center.

The existence of shell middens on the gentle slope facing south of Sukumo Bay has been known since antiquity, but came to the attention of academia only in 1891, when they were first excavated.

The mounds are located approximately 60 meters apart and form the largest known shell midden in Shikoku, both in terms of size and in number of excavated artifacts.

[2] The site is about five minutes by car from Tosa Kuroshio Railway Sukumo Station.