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Sayama Formation (Makiyama, 1930) Fujimoto, 1932

Invalid synonym: Hakonegasaki Formation

• Type locality: Osawa, Ishihata, Mizuho city, Nishitama county, Tokyo
• Coherent formation
• late Pliocene - early Pleistocene
• Correlation: Bushi Formation

• Sedimentary facies: Marine, Fluvial
• Sedimentary facies: Inner bay, Seashore
• Depth of water: Mudflat, Intertidal, Lower intertidal
• Sedimentary structures: Many local unconformities, Planar cross-stratification, Pipe rocks

• Thickness: ca. 50 m
• Upper limit: Unconformity (Imokubo Formation)

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

• Distribution: Osawa, Ishihata, Mizuho city, Nishitama county, Tokyo; Zoshiki, Higashiyamato city, Tokyo; Mitsugi - Shinmei, Musashimurayama city, Tokyo; Kanahorizawa creek, Miyadera, Iruma city, Saitama pref.; Sanpoiri Tokorozawa city, Saitama pref.
• Fossils: Bivalves (Brackish), Ostrea gigas, Diatoms (Freshwater, Brackish)
• Fossils (Plants): Davidia involucrata, Juglans megacinerea, Liquidamber sp., Metasequoia disticha
• Fossils (Trace fossils): Macaronichnus segregatis, Ophiomorpha isp., Rosselia isp.
• Tephra: SYG, SGO, Tmg-R4, Ebs-Fkd, Kd44-Nk, Imokubo Tephra, Zoshiki Tephra, Hakonegasaki Tephra Group

• Suzuki et al. (2016) Jour. Geol. Soc. Japan, vol.122, no.7, pp.343-356, DOI
• Ueki and Sakai (2007) Geology of the Ome District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 189p. (in Japanese with English abstract 5p.)