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Re: mammals over dinosaurs in continuous sequence
Message text written by INTERNET:Dinogeorge@aol.com
>All these responses are very interesting, but the question being addressed
is
where in the world is there a K-T boundary sequence with dinosaur fossils
below the boundary and no dinosaur fossils, only mammals, above it.<
There's a site just west of Denver (in Golden, actually) called South Table
Mesa which is approximately 2/3 Late Cretaceous Denver Formation and 1/3
(at the top) Early Paleocene Denver Formation. Both sections have produced
fossils, dinosaurs below (the type of _Ornithomimus velox_ was found in the
same formation very nearby; I'm not sure about mammals in the Cretaceous
part), and a nice partial skull of _Baioconodon denverensis_ as well as
plant fossils above. Oddly, last I heard, no one had found iridium on the
mesa, and the precise location (stratigraphically speaking) of the boundary
is unknown. However, the presence throughout the formation of dated
volcanic ashes demonstrates that the boundary is in there, somewhere...
Anyone who's been to Dinosaur Ridge and seen the footprints in the Dakota
there have inevitably looked north and seen the mesa.
_,_
____/_\,) .. _
--____-===( _\/ \\/ \-----_---__
/\ ' ^__/>/\____\--------
__________/__\_ ____________________________.//__.//_________
Jerry D. Harris
Fossil Preparation Lab
New Mexico Museum of Natural History
1801 Mountain Rd NW
Albuquerque NM 87104-1375
Phone: (505) 899-2809
Fax: ; (505) 841-2866
102354.2222@compuserve.com