The predecessor of Hachiro Lagoon was the sea
Just beneath the surface is the fill from land reclamation.
Below that, there is a layer rich in Yamato shijimi (Corbicula japonica), which thrive in brackish water, indicating that this sediment was deposited in Lake Hachirogata.
This layer dates back to around 2,000 years ago.
Beneath it lies a layer of sand and small stones, abundant with marine shells, which was deposited in the sea approximately 6,000 years ago.
This peeled sample reveals the story of how Lake Hachirogata was shaped by the changing sea.
[Block Sample]
The sample contains four species of bivalves and three species of snails.
Many of the bivalves are found with both shells intact, suggesting they were buried in the same area where they originally lived.
