The so-called ”Kasaisi” (Mushroom-shaped stone) is almost 9 feet high, and reddish ”brown in color. At least 12 stones are now left in the island. Its history is quite -uncertain. Regarding the origin there have been many opinions, one of which stated that it was derived from the stupa, while another mentioned that it might be a kind of menhir. From the consideration on the morphological comparison and the distribution of the related customs in the main land it may be concluded that the ”Kasaisi” may be a relic of sexual worship.