Re: US Fossil Collections

["Rich Hengst" <rhengst@davros.cc.purduenc.edu>]

On Fri, 7 Apr 1995 00:19:06 -0400, Jerry D. Harris wrote:

>>But,last year someone discovered dinosaur tracks in China. They were
>>found IN TERTIARY ROCKS (my emphasis). Last I heard they were going to

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>>
>>Ray McAllister, Prof (Emeritus) Ocean Eng.,
>
>Dr. McAllister et al -
>
>        Can you provide a reference for these tracks?  I haven't heard of
>them.  I _do_ know, however, that Keith Rigby, Jr., of Notre Dame and his

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>
        Already, though, many people are (rightfully, to my way of
>thinking) doubting his findings -- the attribution of these skeletons to
>the Paleocene is based on some iffy vertebrate associations of the
>dinosaurs with Paleocene mammals.
>
>
>Jerry D. Harris
>Denver Museum of Natural History
>
Assuming that you are speaking of Rigby's work, I helped excavate some of 
those tracks in southern china.  They are situated in LATE Cretaceous 
sediments but certainly not tertiary, unless new tracks were found this 
year by a group other than Rigby's.  Jerry Harris is correct in the 
proximity of advanced mammals located VERY close to dinosaur egg sites.  
Part of the problem is what constitutes the K-T boundary in that area.  It 
is easy to define by fossil criteria but difficult to corroborate or 
date by independent means.  Thus, the ash analysis and some stratigraphic 
work.  As of this moment I would have a tough time saying if the dino egg 
evidence is tertiary or the mammal evidence Cretaceous. But then, I don't 
have to...
A plea, as a middle-aged man who backpacked 85 pounds of ash samples for 
15 miles, I implore you geochemists to find a way that requires, in fact 
demands, that really, really, small sample sizes are the only thing you 
will accept for analysis and dating.

Rich Hengst
Biol. Sci. 
Purdue Univ. North Central
Westville, IN  46391