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Tenoko Formation Tokunaga and Tanai, 1954

• Type locality: Tenoko, Iide city, Nishiokitama county, Yamagata prefecture
• Coherent formation
• early - late Pliocene (4.4, 3.4, 2.6 Ma, FT)

• Sedimentary facies: Fluvial
• Sedimentary facies: Meandering river
• Sedimentary facies (Lower): Flood flow deposit
• Lithofacies: Sandstone, Conglomerate, Mudstone
• Lithofacies (Minor): Lignite, Tuff
• Lithofacies (Lower): Interbedded sandstone and conglomerate
• Lithofacies (Basal): Koyasawa Pyroclastic Flow Deposit
• Sedimentary structures: Trough cross-stratification, Imbrication
• Sedimentary structures (Lower): Parallel stratification, Low-angle cross stratification, Ripple stratification

• Thickness: ca. 230 - 500 m
• Upper limit: Bottom of the horizon intercalating thick conglomerate beds
• Upper limit: Conformity (Nakahara Formation)
• Lower limit: Bottom of Koyasawa Pyroclastic Flow Deposit
• Lower limit: Conformity (Takamine Formation)

• Distribution: Tenoko - Kazuma - Koetosawa - Sugo bridge, Iide city, Nishiokitama county, Yamagata pref.
• Fossils (Upper, Tenoko flora): Comptonia kotoi, Menyanthus cf. trifoliata
• Fossils (Lower, Takamine flora): Acer nordenskioeldi, Alnus miojaponica, Berchemia miofloribunda, Camellia protojaponica, Carpinus heigunensis, Carpinus subcordata, Catalpa sp., Celtis nathorstii, Cercidphyllum crenatum, Cinnamomum akitaense, Cinnamomum miocenum, Cladrastis chaneyi, Corylus takaminensis, Fagus stuxbergi, Ficus sp., Fraxinus takaminensis, Gledtsia miosinensis, Glyptostrobus europaeus, Ilex cf. goshiensis, Ilex subcornuta, Kalopanax acerifolius, Lindera miyataensis, Liquidambar cordata, Liquidambar protopalmata, Liriodendron honsyuensis, Maackia onoei, Metasequoia occidentalis, Myssa sp., Paliurus protonipponicus, Parrotia pristina, Poacites sp., Populus sambonsgii, Pterocarya japonica, Pterocarya protostenoptera, Pueraria sp., Pyrus hokiensis, Rosa cf. usyuensis, Sabia cf. japonica, Salix k-suzukii, Salix takaminensis, Saplum mogiensis, Sasa sp., Sassafras cf. yabei, Sequoia langsdorfii, Smilax trinervis, Sophora miojaponica, Stewartia okutsui, Stewartia submonadelpha, Taxodium dublum, Tilia distans, Ulmus cf. longifolia, Ulmus protojaponica, Wisteria fallax, Zelkova ungeri
• Tephra: Koyasawa Pyroclastic Flow Deposit

• Yanagisawa and Yamamoto (1998) Geology of the Tamaniwa District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 94p. (in Japanese with English abstract 4p.)