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Narioka Formation (Masuda et al., 1974) Yamamoto, 1999

• Type locality: Aga river, Yagoshima - Toyonari, Shimogo city, Minamiaizu county, Fukushima prefecture
• Volcanic rocks
• Collapse caldera-fill deposit
• Pleistocene

• Sedimentary facies: Terrestrial
• Lithofacies (Lacustrine): Sandstone, Conglomerate, Siltstone
• Lithofacies (Lacustrine, Minor): Breccia
• Sedimentary structures (Lacustrine): Graded bedding, Reversed graded bedding, Parallel stratification

• Thickness (Overall): ca. 350 m
• Thickness (Lacustrine): ca. 200 m
• Lower limit: Unconformity (Shimogo Formation, Tenei Pyroclastic Flow Deposit, Tsurugaike Debris Avalanche Deposit)
• Lower limit: Unconformity (Late Cretaceous granodiorite, Hiwada Formation, Ono Formation, Tonohetsuri Formation)

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

• Distribution: Aga river, Yagoshima - Toyonari, Shimogo city, Minamiaizu county, Fukushima pref.; Kadotani river, Shimogo city, Minamiaizu county, Fukushima pref.
• Fossils: Diatoms (Freshwater)
• Fossils (related to Todera flora): Acer diabolicum, Acer mono, Acer palmatum, Betula grossa, Betula maximowicziana, Carpinus cordata, Carpinus japonica, Celtis jessoensis, Chamaecyparis pisifera, Fagus crenata, Fraxinus lanuginosa, Ilex geniculata, Juglans ailantifolia, Pinus sp., Potamogeton sp., Quercus cf. dentata, Quercus mongolica var. grosseserrata, Quercus serrata, Rhododendron sp., Rosa sp., Salix sp., Sasa sp., Sorbus commixta, Thuja standishii, Tilia japonica, Tilia maximowicziana, Ulmus davidiana var. japonica

• Yamamoto (1999) Geology of the Tajima District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 85p. (in Japanese with English abstract 8p.)