The Futatsumori Shell Midden is located on a 30 meters high plateau, where River Takase meets River Aka, on the southwest bank of Lake Ogawara. The site is a settlement with a large shell midden from the Early to the Middle Jomon period (approximately 3500 to 2000 BC). In additions to 27 types of shellfishes (Japanese basket clams, common orient clams, scallops, and oysters), the middens also contained fragments of pit dwellings, storage holes, graves, pottery, tools, decorated bones, bones from fish, boars, swans, ducks and other animals, and bones from human beings.Among all of the shells and bones, four pieces (Sword-Shaped Tool made of whalebone, Projectile Point made of antler bone, Ornament made of boar teeth, and Fork-like Item made of antler bone) have been recognized as Prefectural Important Cultural Properties. Now the Futatsumori Shell Midden is under preservation as a historic park.