I think for this era, fungi and other consumers of decaying matter could not break down the cellulose walls of plant matter. Since then they did. It is interest

I think for this era, fungi and other consumers of decaying matter could not break down the cellulose walls of plant matter. Since then they did. It is interesting to imagine a species gaining sentience on a planet where there was no coal or oil to power from a wood-burning society of iron to steel and plastics.