Oginoyama - Oginosen

A mountain located in the northeastern part of Tottori Prefecture, near the border with Hyogo Prefecture. It is 1,310 meters above sea level. Its name comes from its inverted fan-shaped shape. It is a volcano in the Daisen volcanic group. Rhyolite and andesite erupted at the end of the Tertiary Period, breaking through the Miocene green tuff bedrock, and then were covered by the early Quaternary period dipyroxene andesite lava flows, giving it an aspite-type mountain shape. The Anagara near the summit is thought to be a later crater. Apart from horse chestnut, Japanese walnut, and katsura trees in the valley, the remaining primeval forests of beech and nemagaridake trees that were seen up to the summit have been reduced by logging. The Sugano sphagnum moss marsh is located on the mountainside, and the Japanese giant salamander lives in the river valley. Kawaidani Plateau is a suitable place for skiing, camping, and wild vegetable gathering, and is home to a prefectural pasture and a great view. It forms the northern part of Hyonosen-Ushiroyama-Nagisan Quasi-National Park.

[Minoru Iwanaga]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

鳥取県北東部、兵庫県境付近にある山。標高1310メートル。逆扇形の山形が呼び名となった。大山(だいせん)火山系の火山。中新世の緑色凝灰岩からなる基盤を破って、第三紀末に流紋岩や安山岩が噴出、ついで第四紀初頭の複輝石安山岩溶岩流がこれらを覆い、アスピーテ型の山容を示す。頂上付近の穴ヶ原はその後の噴火口と推定される。植生は渓谷部のトチノキ、サワグルミ、カツラなどは別として、頂上部までにみられたブナ、ネマガリダケなどの残存原始林は伐採で少なくなった。山腹には菅野(すがの)のミズゴケ湿原があり、河谷にはハコネサンショウウオが生息する。河合谷高原(かわいだにこうげん)はスキー、キャンプ、山菜採集の適地で、県営放牧場があり、好展望地。氷ノ山後山那岐山(ひょうのせんうしろやまなぎさん)国定公園の北部を構成する。

［岩永　實］

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