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Re: Preservation bias



In a message dated 97-04-11 03:31:27 EDT, sarima@ix.netcom.com (Stanley
Friesen) writes:

<< The qualification is that the plant and animal fossils (except for a few
 shellfish) are generally in different specific beds within these
 formations.  This still leaves them quite close together in places,
 sometimes just a few meters apart. >>

The occurrence of plant fossils with animal fossils is common enough that
I've been wondering why the question even came up. For example, the
Bernissart _Iguanodon_ skeletons were discovered in a coal mine, and coal, as
we all know, is a quintessential plant fossil. The type skeleton of
_Agathaumas sylvestris_ ("forest-dwelling marvel") was discovered reposing on
a bed of fossil leaves, hence the "sylvestris" in its scientific name, and
the type skeleton of _Scolosaurus cutleri_ had a splendid leaf impression in
the belly. The type skeleton of _Compsognathus corallestris_ has its manus
portions obscured by a piece of plant debris, which caused its describers to
suggest that its forelimbs were modified into flippers.

In Dinosaur Provincial Park, Alberta, where I volunteered as a collector for
a few weeks during the summers of 1979 and 1980, fossil wood was routinely
mistaken (especially by >this< novice) for fossil bone. The wood is generally
compressed and "coalized," and sometimes there are tiny amber crystals
imbedded in it, the fossilized remnants of sap. Not infrequently there are
also pretty seed cone impressions. In 1980, we excavated a nice hadrosaur
skeleton that was partially wrapped around a tree trunk (it's now in a floor
display at the Tyrrell Museum), where it came to rest after floating
downstream some 75 million years ago. And the bedding plane of the partial
_Chirostenotes_ skeleton we pulled out in 1979 was shot through with fossil
wood.