Re: Study Backs Quick End of Dinosaurs

[Phillip Bigelow <bh162@scn.org>]

On Wed, 31 May 2000, Timothy Williams wrote:

> By way of Larry Dunn:
> 
> 
> William Clemens addresses this point:
> 
> >Clemens said that the weakness of the Sheehan study is
> >that it fails to go back far enough in history. He
> >said that deposits five million and six million years
> >old contain a much richer variety and number of
> >dinosaur fossils,

If one compares the Judith River Local Fauna (Campanian) to the Hell Creek
Faunal Facies (Maastrichtian), there is abundant evidence that the number
of dinosaur *taxa* have declined in the Hell Creek Faunal Facies. But I
have read nothing about dinosaur *population* numbers declining.  Does
anybody have a ref. to back up Clemens' claim? 


> suggesting the animals were
> >declining when the Hell Creek formation was deposited.


I don't see why this fact (and it is a fact) should weaken the Sheehan et al.
study.  While it's true that their paper doesn't do a good job of
addressing the gradualism vs. catastophism issue, it does provide better
data on the status of dinosaurians in the last 3 meters of Maastrictian
deposition than we had previously. And for such people as
stratigraphers/biostratigraphers/theorists, that is a real contribution to
science.  Frankly, I think it's one of the better dino-related papers to
have come out so far this year.  ;-) 

Small steps, people.  Small steps.

                       <pb>