Re: "No Bolides!"

[tidwell@ix.netcom.com (Virginia Tidwell )]

Tomwrote: 
>
>Besides, many of the above taxa such as the dinosaurs and ammonites 
were
>doing well beforet the catastrophe and then suddenly disappeared. In 
all
>likelyhood, _yes_ it was a bolide that started it all!
>
>Regards,
>Thomas R. Lipka
>Paleontological/Geological Studies
>
  Within the last few years some good evidence has been presented 
showing a marked decline of general dinosaur diversity on the generic 
level during the late Cretaceous.  Although the taxa that are found 
near the K/T seem to be well represented by large numbers of 
individuals,  faunal lists from the Western Interior of N.A. for that 
time period suggest that a large number of genera had become extinct 
during the late Cretaceous with out any replacement groups filling in 
the empty niches.  It may be misleading to say that dinos were doing 
well until the impact.  Rather, it would appear that select taxa were 
thriving at the time.  
  It is also dangerous to make projections about global dinosaur 
populations based on the limited data currently available from 
Cretaceous terrestrial localities.  

          Cautous, but curious in Denver,
            Virginia Tidwell