The peninsula has a larger, more elaborate torii that extends outward into the water, just past the shrine of Mika the priest. Mika has a Wanted List that can be cleared for a reward, and there is a geyser behind his shrine that can be boosted up with Waterspout to reach a treasure chest on one of the torii crossbars.
At the beginning of the game, the Moon Cave lies at the very end of the peninsula, although it is not visible until Amaterasu passes through the large torii. The cave entrance is sealed off until its Demonic Incantation can be broken with the Serpent Crystal.
When Orochi chooses Kushi as a sacrifice, Waka traps Amaterasu and Issun inside the barrier and disappears. Disguised as one of Orochi's Imp minions, Amaterasu searches through Orochi's lair until she finally finds her way to the top level to confront the monstrous beast with Susano. The Moon Cave vanishes upon Orochi's defeat, transforming its former terrain to a simple sandbar with a small guardian shrine at its tip.