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Kozono Formation Fujimoto and Watabe, 1947

Invalids synonym: Gotanda Formation, Tachigase Formation

• Type locality: Arakawa river, Kozono, Yorii city, Osato county, Saitama prefecture
• Coherent formation
• Early Miocene (17.0 - 16.5 Ma)
• Correlation: Shirasu Formation, Tomita Formation, Ushibuse Formation
• Correlation (Upper): Nenokami Formation

• Sedimentary facies: Marine, Brackish
• Sedimentary facies: Tidal sands
• Depth of water (Upper): Shallow
• Lithofacies (Upper): Interbedded sandstone and siltstone
• Lithofacies (Lower): Conglomerate, Arkose sandstone
• Lithofacies (Lower, Minor): Lignite

• Thickness: ca. 110 - 400 m
• Upper limit: Conformity (Arakawa Formation)
• Lower limit: Unconformity (Kinshozan Quartz Diorite, Yorii Formation)

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

• Distribution: Kozono - Tachigase, Yorii city, Osato county, Saitama pref.; Ogawa city, Hiki county, Saitama pref.
• Fossils: Foraminifera, Lignite, Siliceous woods
• Fossils (Kadonosawa fauna): Acila sp., Anadara sp., Arca sp., Bulla sp., Cerithidea sp., Chlamys sp., Clementia sp., Corbicula sp., Corbula nisatoensis, Crassatellites sp., Crassostrea gravitesta, Cultellus sp., Cyclina chinensis, Cyclina japonica, Dentalium sp., Diplodonta ferruginata, Dosinia sp., Epitonium sp., Fulgoraria striata, Glycymeris cf. direlicta, Hemifusus? sp., Hiatula minoensis, Katherinella cf. iizukai, Lamelliconcha kawadai, Lucinoma sp., Macoma aomoriensis, Macoma cf. optiva, Macoma cf. tokyoensis, Mactra sp., Margarites? sp., Meretrix arugai, Mizuhopecten sp., Nuculana sp., Ostrea gravitesta, Pecten sp., Pitar cf. itoi, Pollia sp., Saxolucina cf. khataii, Solen cf. gouldi, Soletellina minoensis, Striarca sp., Tapes sp., Tateiwai tateiwai, Tateiwai yamanarii, Turritella chichibuensis, Trigonaphera sp., Venus sp., Vicarya callosa japonica, Vicaryella atukoae, Vicaryella cf. chosenica, Vicaryella ishiiana, Vicaryella nipponica, Vicaryella tyosenica, Yoldia sp.

• Takagi et al. (2016) Jour. Geol. Soc. Japan, vol.122, no.7, pp.305-324, DOI
• Arai et al. (2009) Jour. Geol. Soc. Japan, vol.115, no.5, pp.223-241 DOI
• Takahashi and Yanagisawa (2004) Jour. Geol. Soc. Japan, vol.122, no.12, pp.625-635.
• Makimoto and Takeuchi (1992) Geology of the Yorii District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 136p. (in Japanese with English abstract 6p.)