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RE: New in Science
> -----Original Message-----
> From: email@example.com [mailto:firstname.lastname@example.org]On Behalf Of
> Sent: Friday, May 11, 2001 8:57 AM
> To: email@example.com; firstname.lastname@example.org
> Subject: Re: New in Science
> In a message dated 5/11/01 12:56:00 AM, email@example.com writes:
> << the Triassic-Jurassic Boundary Mass Extinction >>
> There was no Triassic-Jurassic Boundary mass extinction, the
> event took place
> between the Norian and Rhietian stages of the late Triassic.
On land, yes. In the seas, however, there is a big extinction event at (or
very close to) the Tr-J boundary: conodonts wiped out, ammonoids and some
other groups suffer major crashes, etc.
> the Jurassic
> begins with the Lias instead of the Rhietian an interesting
> question that I
> don't know the answer to.
Because Period boundaries were established using marine invertebrates rather
than the rare terrestrial vertebrates.
Thomas R. Holtz, Jr.
Department of Geology Director, Earth, Life & Time Program
University of Maryland College Park Scholars
College Park, MD 20742
Phone: 301-405-4084 Email: firstname.lastname@example.org
Fax (Geol): 301-314-9661 Fax (CPS-ELT): 301-405-0796