Hikiiwa Rocks are a group of huge rocks located in the upstream of the Inari River, one of the tributaries of the Aizu River in Inari-cho, Tanabe City, Wakayama Pref. The rocks are composed of a thick sand stone layer that was formed during Miocene epoch of Cenozoic era. A long period of erosion and water flow of the Inari River has made it into the present shape. The name comes from the shape of the rocks, which look like toads sitting in line and looking up at the sky. Largest ones are about 45 m tall, among which the huge rock on the Inari River is designated as a prefectural Natural Monument. There is a Kannon statue called Iwaya Kannon placed in a large grotto created in one of the rocks. The Kannon stood at the top of the steep stairs. Kumagusu Minakata, a natural historian in the Meiji period, often visited this area to collect plants and fungi, to which he referred in his later literature.