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Bihoku Group

Invalid synonym: Tari Group (Local name in Tottori pref.)

• Type locality: Miyoshi city - Shobara city, Hiroshima prefecture
• Coherent formation
• Miocene
• Correlation: Nichiôji Formation, Ukan Formation

• Sedimentary facies: Marine
• Lithofacies (Upper): Siltstone
• Lithofacies (Lower): Conglomerate, Sandstone
• Sedimentary structures (Lower): Cross stratification

• Thickness: ca. 30 - 80 m
• Lower limit: Unconformity (Mikunisan Rhyolites, Sasao Body, Serpentinite)

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

• Distribution: Miyoshi city, Hiroshima pref.; Dogoyama station, Saijo town, Shobara city, Hiroshima pref.; Tari, Nichinan city, Hino county, Tottori pref.; Muroharagawa river, Niinohara, Okuizumo city, Nita county, Shimane pref.; Kamiichi - Sasao - Shimokumatani - Maio, Niimi city, Okayama pref.
• Fossils: Crabs (Callianassa sp., Cancer sanbonsugi), Brachiopods (Terebratalia sp., ), Pollen (Bruguiera sp.)
• Fossils (Echinoids): Brissops makiyamai, Linthia tokunagai, Prionocidaris sp., Schizaster sp., Stereocidaris sp.
• Fossils (Shellfishes): Anadara daitokudoensis, Anomia sp., Batillaria tateiwai, Cardium (Bucardium) ogurai, Chlamys sp., Clementia sp., Corbicula sp., Corbula sp., Cyclina sp., Dentalium sp., Diplodonta sp., Doliocassis cf. japonica, Euspira sp., Geloina sp., Julia sp., Katelysia (Nipponomarcia) nakamurai, Leucoma sp., Lima sp., Macoma sp., Nassarius kometubus, Notocorbura sp., Ostrea gigas, Paphia sp., Pholadomya tukunagai, Pitar sp., Polinices sp., Propeamussium tateiwai, Protorotella yuantaniensis, Protothaca sp., Soletellina sp., Tellina sp., Teredo sp., Tritia sp., Vicaryella cf. bacula
• Fossils (Foraminifera): Cassidullina cf. sblimbata, Cibicides lobatulus, Cibicides pseudoungerianus, Discopulvinulina bradyi, Discopulvinulina cf. nitida, Dyocibicides sp., Elphidiella momiyamaensis, Elphidium advenum, Eponides tanaii, Eponides umbonata, Gaudryina? sp., Globorotalia sp., Hanzawaia nipponica, Quinqueloculina controrta, Quinqueloculina seminula, Quinqueloculina seminula, Quinqueloculina cf. vulgaris, Robulus sp., Rotalia beccari, Rotalia tochigiensis, Triloculina sp., Vaginulina asp., Valvulineria nipponica
• Fossils (Plants): Castanea sp., Comptoniphyllum naumanni, Quercus sp.

• Goto et al. (2013) Jour. Geol. Soc. Japan, vol.119, no.4, pp.321-333 DOI
• Yamanoi et al. (2008) Jour. Geol. Soc. Japan, vol.114, no.5, pp.262-266 DOI
• Hattori (1978) Geology of the Kami-Iwami District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 65p. (in Japanese with English abstract 4p.)
• Igi and Sakamoto (1977) Geology of the Tari District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 45p. (in Japanese with English abstract 7p.)