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Tochikubo Formation Masatani, 1950

• Type locality: Koyamada, Kashima-ku, Minamisoma city, Fukushima prefecture
• Coherent formation
• Late Jurassic, Oxfordian

• Sedimentary facies: Marine, Fluvial
• Sedimentary facies (Top): River mouth, Coastal
• Sedimentary facies (Upper): Meandering river
• Sedimentary facies (Middle): Lacustrine, Floodplain
• Sedimentary facies (Lower): Braided river, Meandering river
• Lithofacies (Upper): Sandstone
• Lithofacies (Middle): Interbedded sandstone and shale
• Lithofacies (Lower): Sandstone
• Lithofacies (Minor): Conglomerate, Coal
• Sedimentary structures: Parallel-stratification

• Thickness: 350 - 500 m
• Upper limit: Bottom of marine facies horizon bearing shellfish fossils and bioturbation
• Upper limit: Transitional (Nakanosawa Formation), Unconformity (Kameoka Formation, Mukaiyama Formation)
• Lower limit: Conformity (Yamagami Formation)

• Distribution: Uda river, Yamakami - Tomizawa - Ikegami - Imada, Soma city, Fukushima pref.; Koyamada - Tochikubo, Kashima ward, Minamisoma city, Fukushima pref.; Ohara - Shidazawa - Oshigama, Haramachi ward, Minamisoma city, Fukushima pref.
• Fossils (Plants): Lycopodiophyta, Equisetales, Seed ferns (Sagenopteris petiolata), Bennettitales (Zamites yabei)
• Fossils (Ferns): Cladophlebis acutipennis, Cladophlebis exiliformis, Cladophlebis isikawaensis, Cladophlebis lobifolia, Cladophlebis undulata nipponensis, Onychiopsis elongata, Sagenopteris petiolata, Taeniopteris somaensis, Taeniatus elongatus, Zamiophyllum cf. buchianum, Zamites yabei
• Fossils (Cycads): Nilssonia orientalis, Nilssoniocladus tairae, Nilssoniocladus japonicus, Pseudoctenis cf. lanei, Ptilophyllum pachyrachis, Ptilophyllum pecten
• Fossils (Pinophyta): Pelourdea nipponica, Podozamites sp.
• Fossils (Footprints): Theropods, Coelurosauria, Reptiles

• 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.)