> There is no bioturbation discussed in the original articles and as a
> Quaternary scientist who has worked with Holocene terrestrial sediments I
> wouldn't expect significant bioturbation in the French sediments described.
Would you expect to find bioturbation in swamps which form peat
deposits? These would be the same swamps which supposedly formed the
Pennsylvanian coal deposits. When I look at the underclays beneath
coal, I commonly observe thin bedding in both the underclay and coal. I
would expect bioturbation and rooting to obliterate all bedding
immediately beneath the coal; what I observe is thin bedding, plant
fragments, and one fossil tree trunk, but no continuous roots attached
to trees as I would expect from a swamp. The coal appears to me to have
been rafted by water and settled to the bottom where it was buried.
I've asked these questions before, but have yet to receive an answer
which explains the observations.