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Futakawa Formation

Tomiyoshi and Takasu (2009) assigned to Southern Chichibu Belt.

• Type locality: Futakawa - Shimizu - Hasegawa, Aridagawa city, Arida county, Wakayama prefecture
• Coherent formation
• Late Cretaceous, Campanian
• Contemporaneous heterotopic facies (Upper): Toyajo Formation

• Sedimentary facies: Shallow marine
• Lithofacies (Top): Shale, Interbedded sandstone and shale
• Lithofacies (Upper): Sandstone
• Lithofacies (Upper, Minor): Conglomerate, Shale
• Lithofacies (Middle): Shale, Interbedded sandstone and shale
• Lithofacies (Lower): Sandstone, Siltstone
• Lithofacies (Lower, Minor): Shale, Conglomerate
• Lithofacies (Bottom): Shale
• Lithofacies (Bottom, Minor): Interbedded sandstone and shale, Limestone
• Lithofacies (Basal): Conglomerate, Sandstone
• Sedimentary structures: Graded bedding

• Thickness: ca. 300 - 1,200 m
• Thickness (Top): 40 - 150 m or thicker
• Thickness (Upper): ca. 40 - 270 m
• Thickness (Middle): ca. 70 - 300 m
• Thickness (Lower): ca. 70 - 400 m
• Thickness (Bottom): ca. 350 - 600 m or thicker
• Thickness (Basal): 0 - 20 m
• Lower limit: Conformity (Goryo Formation, Matsubara Formation), Unconformity (Kurosegawa Belt, Northern Chichibu Belt)

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

• Distribution: Futakawa - Shimizu - Hasegawa, Aridagawa city, Arida county, Wakayama pref.
• Fossils: Brachiopods (Rhynchonella sp., Terebratulina sp.), Echinoids, Solitary corals
• Fossils (Ammonoids): Baculites sp., Eutrephoceras sp., Gaudryceras? sp., Hyphantoceras aff. oshimai, Pentacrinites sp., Polyptychoceras cf. haradanum, Polyptychoceras cf. pseudogaultinum, Pseudoperissites cf. bicarinata, Pseudoxybeloceras? sp.
• Fossils (Shellfishes): Acila sp., Anomia sp., Grammatodon sachalinensis, Inoceramus cf. ezoensis, Inoceramus japonicus, Inoceramus cf. naumanni, Inoceramus schimdti, Lima sp., Loricula sp., Lucina (Myrtea) ezoense, Semifusus (Trochofusus) tuberculatus, Tonna sp.
• Fossils (Limestone): Bryozoans, Calcareous algae

• Yao (2012) Jour. Geol. Soc. Japan, vol.118, Supplement, pp.90-106 DOI
• Tomiyoshi and Takasu, (2009) Jour. Geol. Soc. Japan, vol.115, no.10, pp.540-543 DOI
• Hirayama and Tanaka (1956) Todorogi, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 37p. (in Japanese with English abstract 11p.)
• Hirayama and Tanaka (1956) Kainan, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 62p. (in Japanese with English abstract 12p.)