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Iwaodaki Tuffaceous Sandstone Member (Ikebe et al., 1951) Sumi et al., 1989

• Type locality: Iwaodaki fall, Oyabe city, Toyama prefecture
• Coherent formation
• middle - late Miocene
• Correlation: Nakata Tuff

• Lithofacies: Andesitic tuffaceous sandstone
• Lithofacies (Minor): Mudstone, Tuffaceous mudstone, Lignite
• Sedimentary structures: Parallel stratification, Graded bedding, Slump structures

• Thickness: ca. 30 - 250 m

------ Conformity, ~~~~~~ Unconformity, ~~~--- Local unconformity, '''/,, Interfingered, :::::: Fault, /--/-- Thrust, +__+__ Ground surface, ?--?-- Unknown

• Distribution: Iwaodaki fall - Tanitsubono, Oyabe city, Toyama pref.; Torikura, Fukuoka town, Takaoka city, Toyama pref.; Busshoji, Himi city, Toyama pref.; Konma, Tsubata city, Kahoku county, Ishikawa pref.; Shoshihara, Hodatsushimizu city, Hakui county, Ishikawa pref.
• Fossils: Desmostylus sp. (Molar), Barnacles (Baranus sp.), Argonautidae, Plant fragments
• Fossils (Shellfishes): Cassididae, Chlamys sp., Clinocardium sp., Dentalium sp., Feraniella sp., Fissurellidae, Fulgolaria sp., Megayoldia sp., Natica sp., Nuculana sp., Pecten sp., Portlandia sp., Saccella sp., Turritella sp., Venericardia sp., Yoldia sp.

• Sumi et al. (1989) Geology of the Isurugi District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 118p. (in Japanese with English abstract 5p.)
• Sumi (1978) Geology of the Tsubata District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 55p. (in Japanese with English abstract 4p.)
• Inoue et al. (1964) Johana, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 32p. (in Japanese with English abstract 5p.)