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Kumazawagawa Formation

• Type locality: Kumazawa river, Kazuno city, Akita prefecture
• Volcanic rocks
• middle Miocene (Shellfishes)
• Correlation: Obonai Formation

• Lithofacies (Upper): Tuff, Conglomerate, Sandstone, Shale
• Lithofacies (Lower): Altered andesite, Rhyolite

• Upper limit: Unconformity (Yudamatagawa Lava, Sorinotaki Lava)

• Distribution: Kumazawa river, Kazuno city, Akita pref.; Yudamata river, Tazawako, Senboku city, Akita pref.; Appi river, Hachimantai city, Iwate pref.
• Fossils: Shellfishes

• Kawano and Uemura (1964) Hachimantai, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 36p. (in Japanese with English abstract 8p.)