Irie Site
The Irie Site is a coastal site with large mounds made up of discarded shells and the bones of fish and animals. These shell mounds at the Irie Site were likely formed over several centuries with the top layers of the mounds dating from approximately 2000 BCE. Numerous graves and the sites of pit dwellings have also been discovered.
The archaeological site is open to the public. Displays include a large preserved cross section of earth, shells, and bones taken from one of the mounds and a three-dimensional representation of a pit dwelling. The site is within walking distance of the Takasago Burial Site [link] and the Irie Takasago Museum [link].
The sea and shell mounds
As the climate grew warmer (8000–5000 BCE), sea levels rose, and prime hunting and foraging areas were replaced by shallow bays and fishing and shellfish gathering methods began to develop. Prehistoric communities of northern Japan relied increasingly on these activities for sustenance and consumed large quantities of seafood. As a result, shell mounds formed next to the settlements.
Shell mounds allow archaeologists to study how diets changed over time and in response to environmental factors. The shells of Asian hard clams (Meretrix lusoria) and oysters in lower layers and Japanese cockle (Venerupis philippinarum) shells in higher layers indicate a change in water temperature and sea levels. At the Irie Site, inhabitants of the settlement relied on both fishing and hunting for sustenance, typically consuming more meat and fish than shellfish.
At the entrance to the park, there is a large cross section of one of the shell mounds. It is several meters high and long, and bones and shells are visible in varying quantities. Bones, which include those of fur seals, dolphins, deer, and other fish and animals, feature more prominently than shells.
Fishing implements and trade
A wide variety of fishhooks unearthed at the Irie Site show how fishing implements developed, and larger combination hooks indicate that open-sea fishing was common. Items made with materials not indigenous to Hokkaido, such as boar-tusk ornaments, have been found at the site. These are thought to be evidence of maritime trade with communities on Japan’s main island of Honshu.
Artifacts from the site are displayed at the Irie Takasago Museum [link]. An entrance fee is required. Some basic information is in English.