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Komiji Formation (Kobayashi et al., 1950) Kato and Sato, 1983

• Type locality: Komiji bridge, Ikusaka city, Higashichikuma county, Nagano prefecture
• Coherent formation
• Miocene

• Lithofacies (Upper): Interbedded sandstone and sandy mudstone
• Lithofacies (Lower): Sandstone
• Lithofacies (Lower, Minor): Sandy mudstone, Coal, Conglomerate
• Sedimentary structures (Lower): Graded bedding

• Thickness (Upper): 30 - 300 m or thicker
• Thickness (Lower): 30 - 390 m
• Upper limit: Conformity (Nagaiwa Member), Unconformity (Mitsumineyama Volcanics, Hijiriyama Andesite, Ooka Mudflow Deposit)
• Lower limit: Conformity (Susobana Formation, Shige Member)

• Distribution: Komiji bridge, Ikusaka city, Higashichikuma county, Nagano pref.; Nagaiwa - Kayakariba - Ishitsu - Iriyama - Ashinoshiri, Ooka, Nagano city, Nagano pref.; Taka, Omi city, Higashichikuma county, Nagano pref.
• Fossils: Shellfishes (Corbicula cf. sakaensis, Margritefera sp., Viviparus sp.), Plants (Sequoia sp., Taxodium sp.)

• Kato et al. (1989) Geology of the Omachi District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 111p. (in Japanese with English abstract 7p.)
• Kato and Sato (1983) Geology of the Shinano-Ikeda District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 93p. (in Japanese with English abstract 7p.)
• Kato (1980) Geology of the Sakaki District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 57p. (in Japanese with English abstract 5p.)