Hi everyone. I recently visited a quarry at the north of Spain (more specifically a geographical area called "El Bierzo", famous for its fossils from the carboniferous era) and I found this one, which looks like tree bark with some particular marks. I have found several well preserved fossils at the same quarry but I will upload the pictures later. I have been looking for information about this one in particular but I haven't found out what type of tree it is, has anybody seen this before? Thank you very much!