Artist's Bracket?

Artist's Bracket?

Observation - Artist's Bracket? - UK and Ireland. Description: Near the base of a veteran oak tree. About 30 cm across, semicircular and almost flat. Ruddy brown colour with quite a thin margin. Third photo of slice from bracket appears to show a sterile layer which Fenwickfield suggested could confirm applanatum.

Near the base of a veteran oak tree. About 30 cm across, semicircular and almost flat. Ruddy brown colour with quite a thin margin.
Third photo of slice from bracket appears to show a sterile layer which Fenwickfield suggested could confirm applanatum.