Re: Pennsylvanian Extinction Query

["Ken Kinman" <kinman@hotmail.com>]

Steve,
    I don't think most workers take the periodic mass extinction theory 
very seriously any more.  The Sepkoski-Raup hypothesis caused a stir for a 
while, but the evidence didn't hold up well to closer scrutiny.
    I see no indications at all of any sudden widespread extinctions at the 
end of the Pennsylvanian.  There was a pretty big one at the end of the 
Ordovician, but that doesn't fit the Sepkoski-Raup periodicity model at all.
    If you find some evidence of an end-Pennsylvanian extinction, I would 
be interested to hear about it.  But I really doubt that there was one.  
There were a lot of interesting evolutionary developments between the 
end-Devonian extinction and the end-Permian extinction, but I think the end 
of the Pennsylvanian was pretty quiet by comparison.  Changes continued to 
happen, but I see nothing particularly sudden at that time.
            ----Cheers,   Ken

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