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Re: Archaeopteryx's birthday

At 12:35 PM 11/16/96 +1030, you wrote:
>   None of the references I have, including _The Dinosauria_, lists the
>era/stage that Archaeopteryx is associated with.  They merely say "Late
>Jurassic."  Anybody happen to know the era/stage Archie is associated with?

Archaeopteryx is from the Kimmeridgian (middle Late Jurassic), c.
154.7-152.1 Ma.  Incidentally, almost all the recent geochron work
(biostrat, isotope, etc.) shows that the vast majority of Morrison dinosaur
bearing horizons are ALSO Kimmeridgian (including Dry Mesa, which turns out
to be from the middle, not the top, of the stack).  We really don't know
what Tithonian (late Late Jurassic) dinos looked like, unless Tendaguru
and/or the Chinese Late J dinos turn out to be Tithonian.

Thomas R. Holtz, Jr.
Vertebrate Paleontologist     Webpage: http://www.geol.umd.edu
Dept. of Geology              Email:th81@umail.umd.edu
University of Maryland        Phone:301-405-4084
College Park, MD  20742       Fax:  301-314-9661

"To trace that life in its manifold changes through past ages to the present
is a ... difficult task, but one from which modern science does not shrink.
In this wide field, every earnest effort will meet with some degree of
success; every year will add new and important facts; and every generation
will bring to light some law, in accordance with which ancient life has been
changed into life as we see it around us to-day."
        --O.C. Marsh, Vice Presidential Address, AAAS, August 30, 1877