Erect fossil stumps were found from the outcrop of the Upper Triassic Hinabata Formation, the uppermost part of
the Nariwa Group at Hinabata, Nariwa-cho,Takahashi City, Okayama Prefecture, SW Japan. They are evidence of
the oldest fossil forest in Japan. The Upper Triassic Nariwa Group is mostly composed of non-marine deposits
except the marine Jito Formation and characterized by the abundance in plant fossils. The marine Jito Formation is
characterized by occurrence of Norian Monotis ochotica. On the basis of detailed observation of the occurrence of
erect fossil stumps, as well as sedimentary facies of fossil-bearing unit, the fossil forest was interpreted to have
grown on the top of the natural-levee units. One of the erect fossil stumps was identified as Xenoxylon sp.