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Re: Paleocene Dinosaurs

Allison R Tumarkin wrote:
>  The problem with channel deposits is that a
> stream will transport (1) remains of recently-dead animals AND (2)
> previously buried (sometimes already fossilized) remains derived from the
> older deposits which the stream is eroding.  Thus the presence of
> unassociated, disarticulated dinosaur bits in Paleocene stream deposits
> does not necessarily mean that dinosaurs survived into the Paleocene, but
> only shows that the Paleocene stream eroded Mesozoic strata and picked up
> some dinosaur bones/teeth in the process.

Exactly. Imagine my surprise when I discovered a Mesozoic ammonite
weathering out of Oligocene sediments in N.W. Nebraska. I would guess
that during the Oligocene the ammonite was washed down from the higher
areas of the nearby Black Hills, where ammonite-bearing strata abounds
and deposited in the floodplain. 

Adam Black
Wildlife Art of the Tertiary & Pleistocene
Archer, Florida