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Re: A Jurassic 'beaver'

At 10:08 PM +0100 2/23/06, David Marjanovic wrote:
>> And for the dinosaur connection, it comes from the same deposits as
>> Pedopenna, the enigmatic 'feather-foot' theropod.
>Eh, but in this case it is early to middle Early Cretaceous in age, not
>Middle Jurassic. (I sent the ref to the list a few months ago.)

They cite three references for the 164 million year date:
W Chen, Q. Ji, D-Y Liu et al, Geol Bull China 23, 1165 (in Chinese) (2004)
Y-O Liu, Y-X Liu, Geophysical Res Lett 32, L12314, (2005)
Q. Ji et al, Mesozoic Jehol Biota of Western Liaoning China (Geol Publ House, 
Beijing, 2004)

If my recollection is correct, the second of these is a radiometric date. What 
has been questioned is the interpretation of the stratigraphy. I have not seen 
the other two references. 
Jeff Hecht, science & technology writer
jeff@jeffhecht.com  http://www.jhecht.net
Boston Correspondent: New Scientist magazine
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