Re: Fastovsky vs Archibald

[Phil Bigelow <bigelowp@juno.com>]

> 
> But 
> it
> is nearly impossible to identify an undisputed extinction horizon 
> within
> a formation.  Absence of evidence is not necessarily evidence of 
> absence.


I'd better amend that statement a bit.  Although the point is accurate
sensu stricto, there are some cases where extinctions are interpreted to
have occurred with a high confidence level (the K-T boundary layer is one
example).  But these exceptions are rather uncommon and they tend to be
associated with special circumstances (such as an association with an
iridium layer).  But in most (typical) cases where species appear to
"disappear" within a rock formation, the Signor-Lipps Effect tends to
dominate.

In some U.S. states, a criminal suspect cannot be charged with a murder
if the body of the purported victim cannot be found.  Trying to prove
that the ancient disappearance of a species was due to its extinction is
a much more complex problem.

<pb>
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