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Kumi Formation Okubo, 1981

• Type locality: Lake Shintameike, Okinoshima city, Oki county, Shimane prefecture
• Coherent formation
• Miocene (16.5 - 9.5 Ma)
• Intruded by: Hei Trachyte, Kamo Rhyolite
• Correlation: Igo Mudstone

• Lithofacies (Upper): Mudstone, Tuffaceous mudstone
• Lithofacies (Upper, Minor): Diatomite, Glauconite
• Lithofacies (Lower): Sandstone-dominant interbedded sandstone and mudstone

• Thickness (Upper): 500 m or thicker
• Thickness (Upper, Diatomite): ca. 100 m
• Thickness (Lower): ca. 150 m
• Distribution: Several km² or less
• Upper limit: Unconformity (Tsuma Formation, Omosu Formation, Mukogaoka Formation, Omineyama Basalt, Misaki Basalt)
• Lower limit: Unconformity (Kori Formation)

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

• Distribution: Utagi - Lake Shintameike - Hei - Shimonishi - Nishida - Kamo - Minoura - Iinoyama - Mount Soramineyama - Igo-Nakanoura - Nakamura - Nukadani - Tsudo Island Park - Mukoyama - Cape Nagumisaki - Lake Yuinoike - Nogoe - Tokoyamagoe - Mount Terayama, Okinoshima city, Oki county, Shimane pref.
• Fossils: Sharks (Isurus sp.), Sponges (Aphrocallistes sp..?)
• Fossils (Shellfishes): Acila cf. yanagawaensis, Alvenius ojianus, Barbatia sp., Boreotrophon sp., Calyptraea sp., Cardita cf. leana, Cavolina sp., Chrysodomus despectus, Conchocele disjuncta, Conus tokunagai, Delectopecten peckhami, Diodora sp., Euchellus cf. notoensis, Glycymeris sp., Glyptamusium sp., Haliotis notoensis, Limatura kurodai, Macoma izurensis, Mizuhopecten sp., Natica sp., Nemocardium sp., Nerita cf. ishidae, Nipponolimosis cf. azumana, Nuculana (Nuculana) pernula sadoensis, Nuculana sadoensis, Palliolum peckhami, Serripes sp., family Shiphonodentalidae, Shizstar sp., Thyasira bisecta var. nipponica, Thyasira tokunagai, Tugali cf. decussatoides
• Fossils (Foraminifera): Catapsydrax sp., Globigerina angustiumbilicata, Globigerina druryi, Globigerina foliata, Globigerina praebulloides, Globigerina pseudociperoensis, Globigerina weissi, Globigerina woodi, Globigerinida glutinata, Globigerinoides bisphericus, Globigerinoides quadrilobatus trilobus, Globoquadrina altispita, Globoquadrina baroemoenensis, Globoquadrina dehiscens, Globorotalia bykovae, Globorotalia obesa, Globorotalia peripheroronda, Globorotalia cf. praescitula, Globorotalia quinifalcata, Lenticulina sp., Miogypsina sp., Neogloboquadrina cf. continuosa, Neogloboquadrina mayeri, Operculina sp., Sphaerogypsina globulus, Sphaeroidinellopsis disjuncta
• Fossils (Diatoms): Actinocyclus curvatulus, Actinocyclus ehrenbergii, Actinocyclus ellipticus, Actinocyclus kisselevii, Actinocyclus ingens, Actinoptychus campanurifer, Actinoptychus senarius, Actinoptychus splendens, Annellus califormicus, Arachnoidiscus ehrenbergii, Arachnoidiscus ornatus, Aulacosira granulata, Auliscus caelatus, Bidduluphia pulchella, Bidduluphia tuomeyi, Cladogramma sp., Cocconeis antiqua, Cocconeis curvirotunda, Coscinodiscus argus, Coscinodiscus aymbolophorua, Coscinodiscus elegans, Coscinodiscus endoi, Coscinodiscus gigas, Coscinodiscus lewisianus, Coscinodiscus marginatus, Coscinodiscus oculus-iridis, Coscinodiscus radiatus, Coscinodiscus stellaris, Coscinodiscus vetuatiaaimus, Craspedodiacus coscinodisucs, Cyclotella sp., Denticulopsis hyalina, Denticulopsis hustedtii, Denticulopsis kanayae, Denticulaopsis lauta, Denticulopsis nicobarica, Denticulopsis praedimorpha, Denticulopsis praelaauta, Denticulopsis punetata, Denticulopsis punetata var. hustedtii, Diploneia sp., Fragilaria captina, Goniotheaium odontella, Grammatophora sp., Hemiaulus cf. polymorphun, Hyalodiscus sp., Ikebea sp., Mastogloia splendia, Mediaria aplendida, Melosira sol, Navicula sp., Nitzschia sp., Odontella aurita, Paralia sulcata, Rhaphoneis aurirella, Rhaphoneis sp., Rhizosolenia sp., Rutilaria sp., Stephanogonia hanzawae, Stephanopyxia sp., Stictodiscus californicus, Stictodiscus kittonianus, Tabellaria sp., Thalassionema cf. hirosakiensis, Thalassionema nitzschioides, Thalassiosira leptopus, Thalassiosira cf. plicatus, Thalassiosira cf. yabei, Triceratium condecorum, Triceratium pseudonervatum

• Yamauchi et al. (2009) Geology of the Saigo District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 118p. (in Japanese with English abstract 3p.)