Tonda-gawa River in Kamitonda Town doesn’t meander so much, and it flows through low land in an active fault area. Though it’s small in scale in Shimoayukawa in the right bank, a typical river terrace is seen. There is 3 steps of this river terrace, and terrace surface of the second dan eye in about 65 m of altitude which develops most widely is used as plowland, and it’s a place with a lot of place-name with a letter of “flat” and “field”.
It’s said that that former pilgrimage to Kumano throws away a horse by Inaba root Oji in Tonda-gawa River opposite shore and crosses a river first was Ichinose. It was esteemed as a cold-water ablution place and was the location of the purification ceremony to enter Kumano. It’s in the slightly elevated location where Tonda-gawa River went up a mountain a little from a river in the place which narrows.
The biggest terrace in Kamitonda Town over the most substantial 550m and the approximately 1 km of length. 5 of kaisekitani can be checked, and there are ponds where the topography was used and a channel of the 6km attracted in 1833, and it’s also used for irrigation now. A rice paddy and pomiculture are performed on the terrace surface.
Okafuji in this forest was named by Kumagusu Minakata mutation Okafuji, and the raceme is short, and vexilla of a petal is big little, and the one with the dark color is the feature for light white and wing speech for a flower. There is a legend down which a forest of Yahata-jinja Shrine of the Oka-gawa River upper class has floated. It was designated as number 1 of natural monument in a prefecture in 1956.
A plant preffers warm and humid climate is in the swamp in Oka-gawa River, and grows.
The adjustment-lessness of the Muro Group of accretionary prism and the Tanabe Group who accumulated in the forearc basin with which it covers that can be observed. A thick sandstone conglomerate layer of inconsistency (base conglomerate layer) above forms a cliff in Sukuma-dani Gorgei into weathering and erosion hard adjustment-lessly, and a Sukuma-dani Gorge Kannon is built on it. There is a study place where you assume that Ennogyoja held in Sukuma-dani Gorge, and Oguri Hangan’s legend is also left.
Hikogoro-Teibo Embankment is located in the Tonda-gawa River right bank and is the grand embankment whose length is 1 km. An embankment with Hikogorou’s legend which was to the Tomitagawa’s advantage of flood control which repeated a flood for a human sacrifice. 4 tombstones are built on the embankment, and 1 human sacrifice Hikogorou tombstone of honors and 1 set are a Meiji flood invitation and dedication for dead soul monument.
It was necessary to build the bridge which is unbreakable because of the flood by Tonda-gawa River which repeats a flood, and needed a pierless bridge. It’s said that they refered to a bridge that lies underwater, protected from the destructive current in Shimanto-gawa River in Shikoku.