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Tobigamori Formation (Noda, 1934) Onuki, 1956

Invalid synonym: Natsuyama Conglomerate Formation

• Type locality: Mount Tobigamori, Higashiyama village, Higashiiwai city, Iwate prefecture
• Coherent formation
• Late Devonian - early Carboniferous
• Correlation: Ainosawa Formation

• Sedimentary facies: Marine
• Lithofacies (Upper, Main): Mudstone
• Lithofacies (Upper, Minor): Conglomerate, Pebbly mudstone
• Lithofacies (Lower, Main): Mudstone, Interbedded sandstone and mudstone
• Lithofacies (Lower, Minor): Lapilli tuff, Tuff breccia, Tuffaceous conglomerate, Tuff, Tuffaceous sandstone

• Thickness: 1,000 m or thicker
• Upper limit: Conformity
• Lower limit: Unconformity (Motai Metamorphic Rocks, Shoboji Diorite)

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

• Distribution: Minami-Iwairi, Nagasaka, Higashiyama village, Higashiiwai city, Iwate pref.
• Fossils: Trilobites, Bivalves, Gastropods, Bryozoans, Crinoids, Lepidodendron (Leptophloeum rhombicum)
• Fossils (Brachiopods): Crytospirifer tobigamoriensis, Crytospirifer yabei (former descriptions: Spirifer verneuili, Cryptospirifer verneuili)
• Fossils (Ammonoids): Costaclymenia sp., Protocanites sp.

• Tazawa and Niikawa (2018) Jour. Geol. Soc. Japan, vol.124, no.2, pp.111-116 DOI
• Ehiro and Morikiyo (2013) Jour. Geol. Soc. Japan, vol.119, Supplement, pp.47-67 DOI