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Oyamada Formation Takano, 1994

• Type locality: Kamioyamada town, Machida city, Tokyo
• Coherent formation
• Fore-arc basin sediments (Kazusa trough)
• early Pleistocene (1.7 - 1.5 Ma)
• Interfingered: Tsurukawa Formation

• Sedimentary facies (Upper): Shore, Shallow marine
• Sedimentary facies (Middle): Mudflat, Inland bay (Brackish)
• Sedimentary facies (Lower): Fluvial
• Sedimentary facies: A cycle of regression - transgression sequence
• Lithofacies (Upper): Sands
• Lithofacies (Middle): Silt, Sands
• Lithofacies (Lower): Gravels
• Sedimentary structures (Upper): Trough cross-stratification
• Sedimentary structures (Middle): Hummocky cross-stratification, Dune structure, Pipe rocks
• Sedimentary structures (Lower): Channel structure

• Thickness: ca. 30 - 50 m
• Thickness (Upper): 8.6 m or thicker
• Thickness (Middle): 6.6 - 12.3 m or thicker
• Thickness (Lower): 2 - 6 m
• Upper limit: Conformity (Renkoji Formation), Unconformity (Terrace deposit)
• Lower limit: Conformity (Fukushima Formation, Hirayama Formation)

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

• Distribution: Kamioyamada town - Nozuta town, Machida city, Tokyo; Tama river, Sakae town - Hinohoncho town, Hino city, Tokyo; Minamidaira, Hino city, Tokyo; Naganuma park, Naganuma, Hachioji city, Tokyo; Kinugaoka - Shimoyugi - Kamiyugi, Hachioji city, Tokyo; Higashinagano, Tama city, Tokyo
• Fossils: Stegodon aurorae, Shellfishes (Ostrea sp.), Crabs, Fishes, Pollen (Metasequoia sp.)
• Fossils (Plants): Measequoia cfr. glyptostroboides, Pterocayra multistriata
• Fossils (Trace fossils): Proboscidea (Footprints), Even-toed ungulate (Footprints)
• Tephra: HU1, HU2, Zushi 2, Ob4b-6

• Suzuki et al. (2016) Jour. Geol. Soc. Japan, vol.122, no.7, pp.343-356, DOI
• Ueki et al. (2013) Geology of the Hachioji District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 137p. (in Japanese with English abstract 6p.)
• Suzuki and Murata (2011) Jour. Geol. Soc. Japan, vol.117, no.7, pp.379-397 DOI
• Ueki and Sakai (2007) Geology of the Ome District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 189p. (in Japanese with English abstract 5p.)