The area surrounding Mount Haku is one of the few in Japan that contains outcroppings from the Jurassic period of the Mesozoic era. Many of Japan's typical examples of dinosaur fossils were found in this area. One of the major rock outcrops is in the Kuwashima area and is known as the Kuwashima Fossil Wall (桑島化石壁 Kuwashima Kasekikabe).