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The Oi Formation is a palaeontological formation located in the Ichishi region of Central Japan. It is part of the Miocene Ichishi Group, which dates to the Lower Miocene period.[1] The Kamimitsugano tuffaceous sandstone members of the Oi Formation were found to contain two of the oldest fossils of still existent species (the Ophiomusium lymani and Ophiochiton cf. fastigatus).[2][3]

See alsoEdit


  1. ^ MATSUOKA, HIROSHIGE; SAKAKURA, FUJIO; OHE, FUJIO (December 30, 1998). "A Miocene Pseudodontorn". Paleontological Research. 2 (4): 246. Retrieved 23 December 2014.
  2. ^ Feral, Jean-Pierre; Bruno, David (2001). Echinoderm Research 2001. CRC Press. p. 56.
  3. ^ "Ophiomusium lymani". Encyclopedia of Life. National Museum of Natural History (USA). Retrieved 23 December 2014.

Further readingEdit

  • Vickers-Rich, Patricia & Rich, Thomas Hewett (1993); Wildlife of Gondwana. Reed. ISBN 0-7301-0315-3