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Koka Formation (Takaya, 1963) Kawanabe, 1989

• Coherent formation
• Pliocene (2.8 - 2.6 Ma)

• Sedimentary facies: Terrestrial
• Sedimentary facies: Wide and deep lake (Diatoms), Fluvial
• Lithofacies: Sands, Clay
• Lithofacies (Minor): Gravels

• Thickness: ca. 180 - 200 m
• Upper limit: Conformity (Nunobikiyama Alternation Member)
• Lower limit: Conformity (Ayama Formation)

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

• Distribution: Yasu river, Yoshinaga, Konan city, Shiga pref.; Kosaji - Shigaraki, Koka city, Shiga pref.; Shimokomazuki, Hino city, Gamo county, Shiga pref.; Ayama, Iga city, Mie pref.
• Fossils (Plants): Abies sp., Alnus sp., Carex sp., Cathaya sp., Chamaecyparis obtuse, Chamaecyparis pisifera, Cornus sp., Cunninghamia sp., Cyclocarya sp., Dichocarpum sp., Eurya japonica, Fagus microcarpa, Ficus cf. nipponica, Fraxinus sp., Glyptostrobus sp., Lapsana sp., Metasequoia sp., Picea sp., Polygonum sp., Pseudotsuga sp., Salix sp., Sciadopitys sp., Scirpus sp., Sequoia sp., Thuja standishii, Tsuga sp.
• Fossils: Diatoms (Melosira solida), Elephants (Footprints), Deers (Footprints)
• Tephra: Kosaji Tephra

• Wakita et al. (2013) Geology of the Kyoto-Tonambu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 124p. (in Japanese with English abstract 3p.)
• Satoguchi et al. (2012) Jour. Geol. Soc. Japan, vol.118, Supplement, pp.70-78 DOI
• Nakano et al. (2003) Geology of the Minakuchi District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 83p. (in Japanese with English abstract 3p.)
• Yoshida et al. (2003) Geology of the Omi-Hachiman District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 72p. (in Japanese with English abstract 3p.)
• Kimura et al. (1998) Geology of the Kyoto-Tohokubu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 89p. (in Japanese with English abstract 5p.)