Dear friends, let me submit a sample from the alluvial sands of Kyiv, Ukraine.
Please help me decide: is it a concretion or a fossil, and if it is a fossil, what could it be? May be, it is carbonized wood?
As I know, Cenozoic deposits are possible here in Kyiv. In the Paleogene, the territory of Kyiv was covered by the sea (here the bones of the Basilosaurus were found), since the Neogene - land.
I applied vinegar, and my sample does not respond
Thank you in advance for the tips!