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Tazawa Mudstone Member Tanaka and Seki, 1966

• Type locality: Okuchizawa, Tazawa, Azumino city, Nagano prefecture
• Coherent formation
• middle Miocene

• Lithofacies: Mudstone
• Lithofacies (Minor): Sandstone

• Thickness: 400 - 650 m
• Upper limit: Transitional (Hakumaki Sandstone and Conglomerate Member)
• Lower limit: Conformity (Uchimura Formation)

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

• Distribution: Tazawa - Nakagawate - Nigorisawagawa river, Azumino city, Nagano pref.; Nishikibe, Matsumoto city, Nagano pref.
• Fossils (Shellfishes): Adulomya uchimuraensis, Volsella akanudaensis
• Fossils (Foraminifera): Alveolophragmium cf. scitulum, Ammonia hatatatensis, Amphicoryna fukushimaensis, Amphicoryna scalaris, Angulogerina hughesi, Angulogerina kokozuraensis, Anomalinoides sp., Bolivina cf. dilatata, Bolivina striatula, Buccella tanaii, Bulimina striata, Bulizalina sp., Cassidella sp., Cassidulina carinata, Chilostomella sp., Cibicides efulgens, Cibicides lobatulus, Cibicides tani, Cibicidoides asanoi, Cibicidoides mediocris, Cyclamina cf. pacifica, Dentalina decepta, Dentalina subraphana, Dentoglobigerina altispira altispira, Dorothia sp., Elphidium advenum, Elphidium cf. excavatum, Elphidium sendaiense, Epistominella cf. pulchella, Fissurina sp., Fursenkoina sp., Gavelinopsis sp., Glabratella opercularis, Glandulina laevigata, Globigerin aangustiumbilicata, Globigerina eamesi, Globigerina falconensis, Globigerina praebullides, Globigerina woodi, Globigerinella obesa, Globigerinella praesiphonifera, Globigerinita glutinata, Globigerinides immaturus, Globigerinoides obliquus, Globigerinoides quadrilobatus, Globigerinoides saccurifer, Globigerinoides sicanus, Globigerinoides subquadratus, Globigerinoides triloba, Globobulimina cf. affinis, Globobulimina pupoides, Globocassidulina cf. subglobosa, Globoquadrina baroemoensis, Globoquadrina dehiscens, Globorotalia bella, Globorotalia mayeri, Globorotalia peripheroronda, Globorotalia quinifalcata, Globorotalia zealandica, Gyroidina soldanii, Gyroidinoides sp., Hanzawaia nipponica, Haplophragmoides sp., Heterolepa sp., Lagena lievis, Lagena striata, Melonis nicobarensis, Melonis pompilioides, Neogloboquadrina continuosa, Nodosaria koina, Nonionella miocenica, Nonionella stella, Nonionellina sp., Nonion japonicum, Nonion nakosoensis, Oolina melo, Orbulina suturalis, Oridorsalis umbonatus, Praeorbulina glomerosa circularis, Praeorbulina glomerosa curva, Praeorbulina glomerosa glomerosa, Pseudononion subcustata, Pseudoparrella sp., Pseudopolymorphina sp., Pullenia bulloides, Pyrgo sp., Quinqueloculina cf. seminulum, Recurvoides sp., Rosalina sp., Rutherfordoides cf. mexicana, Sphaeroidina sp., Sphaeroidinellopsis disjuncta, Sphaeroidinellopsis seminulina seminulina, Spiroplectammina sp., Stainforthia sp., Stilostomella cf. lepidula, Textularia cf. andenensis, Uvigerina akitaensis, Uvigerina proboscidea, Uvigerina sinboi, Valvulineria nipponica

• Harayama et al. (2009) Geology of the Matsumoto District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 63p. (in Japanese with English abstract 3p.)