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Tomizawa Formation (Tokunaga and Otsuka, 1930) Masatani and Tamura, 1959

• Type locality: Bunazaka - Umazawa, Koyamada, Kashima ward, Minamisoma city, Fukushima prefecture
• Coherent formation
• Late Jurassic, Tithonian

• Sedimentary facies: Fluvial
• Sedimentary facies: Floodplain
• Lithofacies (Upper): Sandstone
• Lithofacies (Upper, Minor): Shale, Sandy shale
• Lithofacies (Lower): Sandstone
• Lithofacies (Lower, Minor): Conglomerate

• Thickness: ca. 350 - 400 m
• Upper limit: Bottom of tuffaceous sandstone bed or shale bed
• Upper limit: Transitional (Koyamada Formation), Unconformity (Kameoka Formation, Tatsunokuchi Formation)
• Lower limit: Bottom of quartz arenite bed
• Lower limit: Conformity (Koike Limestone Member)

• Distribution: Bunazaka - Umazawa - Tomizawa, Koyamada, Kashima ward, Minamisoma city, Fukushima pref.; Obatake - Yamadorisaku, Haramachi ward, Minamisoma city, Fukushima pref.
• Fossils (Plants): Coniopteris? sp., Equisetites sp., Equisetum sp., Kirchneria sp., Onychiopsis elongata, Otozamaites sp., Podozamites sp., Podozamites lanceolatus, Pecopteris sp., Ptillophyllum sp.
• Fossils (Bennettitales): Williamsonia sp.

• Taketani and Osozawa (2013) Jour. Geol. Soc. Japan, vol.119, Supplement, pp.68-81 DOI
• Yanagisawa et al. (1996) Geology of the Somanakamura District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 114p. (in Japanese with English abstract 9p.)
• Kubo et al. (1990) Geology of the Haramachi and Omika District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 138p. (in Japanese with English abstract 7p.)
• Fujita et al. (1988) Geology of the Kakuda District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 99p. (in Japanese with English abstract 9p.)