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Izeki Formation

• Coherent formation
• Late Cretaceous, Coniacian - Santonian

• Sedimentary facies: Marine
• Lithofacies (Top): Shale
• Lithofacies (Upper): Sandstone
• Lithofacies (Upper, Minor): Shale
• Lithofacies (Middle): Shale
• Lithofacies (Middle, Minor): Sandstone
• Lithofacies (Lower): Sandstone
• Lithofacies (Lower, Minor): Shale, Conglomerate
• Lithofacies (Basal): Conglomerate
• Sedimentary structures: Graded bedding

• Thickness: ca. 450 m
• Thickness (Top): ca. 40 m
• Thickness (Upper): ca. 100 - 150 m
• Thickness (Middle): 50 - 80 m
• Thickness (Lower): 100 - 170 m
• Thickness (Basal): ca. 10 - 20 m
• Upper limit: Disconformity (Kamimatsubara Formation)
• Lower limit: Disconformity (Arida Formation), Unconformity (Kurosegawa Belt)

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

• Distribution: Ikadachi - Kamimatsubara, Aridagawa city, Arida county, Wakayama pref.
• Fossils: Echinoids
• Fossils (Shellfishes): Bakevellia? shinanoensis, Corbicula (Paracorbicula) sanchuensis, Gervillia forbesiana, Inoceramus sp., Polymesoda (Costacyrena) radiatostriata, Polymesoda (Isodomella) sp.

• Yao (2012) Jour. Geol. Soc. Japan, vol.118, Supplement, pp.90-106 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.)