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Motohata Formation

• Type locality: Motohata, Waga, Kitakami city, Iwate prefecture
• Coherent formation
• Miocene

• Sedimentary facies: Marine
• Lithofacies: Sandstone, Conglomerate, Siltstone
• Lithofacies (Minor): Dacitic tuff, Lignite
• Lithofacies (Basal): Conglomerate
• Paleocurrent: West to East

• Thickness: 350 - 400 m
• Upper limit: Interfingered (Kunimiyama Andesite)
• Lower limit: Unconformity (Tsunatori Formation, Hishinai Formation)

• Distribution: Motohata, Waga, Kitakami city, Iwate pref.
• Fossils (Shellfishes): Anadara cf. subcrenata, Anadara cf. tatsunokutiensis, Anodontia cf. bialata, Anomia cf. lischkei, Callista brevisiphonata, Cardium gorokuense, Cerastoderma californiense, Chlamys cf. nipponensis, Clinocardium bülowi, Clinocardium pseudofastosum, Cyclina sp., Donax? sp., Dosinia? sp., Fortipecten takahashii, Laternula? sp., Macoma cf. incongrua, Macoma tokyoensis, Macrocallistabrevisiphonata, Mactra? sp., Meretrix sp., Mya japonica, Mytilus sp., Ostrea gigas, Panope japonica, Paphia sp., Patinopecten takahashii, Pitar cf. sendaica, Protothaca sp., Sunetta sp., Tapes sp., Thracia sp., Venerupis? sp., Yoldia sp.

• Ozawa et al. (1971) Geology of the Kawashiri District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 40p. (in Japanese with English abstract 5p.)