Paleonet: Help with some fossils

[Roger D. K. Thomas]

 Dear Jinzhuang,

     Cephalopods are often current-aligned, as in the case of Mississippian
examples in the Grand Canyon that have been interpreted by Creationists as
evidence of the Great Flood (!!).  Ordovician orthoconic cephalopods were
long ago studied and interpreted more conventionally by Richard Reyment as
being oriented horizontally and vertically by marine currents.
     However, the crossbars on your specimens show no indication of being
relatively widely and regularly spaced, like cephalopod chambers.  Also,
some specimens appear to be slightly bent, although this could be a result
of asymmetric compression or structural deformation.  The photograph
appears to show a bedding plane surface.  Is this correct?

     Conulariids, by any chance?

     Kind regards,   Roger


On Thu, Jun 12, 2014 at 2:37 AM, Jinzhuang Xue <pkuxue at pku.edu.cn> wrote:

> Dear all,
>      The attached is a picture showing some conical things horizontally
> laying on the bedding plane of sandstones. They look like stromatolite but
> they are not.  But, are they trace fossils? sedimentary structures? or
> anything else?  We are wondering if anyone here could help us for
> identifying them.  Has anyone found similar things before?  Thanks a lot in
> advance.  The age of the rock is Late Devonian Famennian, and the
> depositional environments may be swamps near coastal area.
>
> All the best,
>
> Jinzhuang Xue
> Peking University
> pkuxue at pku.edu.cn
> 2014-06-12
>
>
>
>
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>


-- 

Roger D. K. Thomas
John Williamson Nevin Professor of Geosciences
Secretary-General, International Palaeontological Association
___________________________________
Department of Earth and Environment
Franklin & Marshall College
P.O. Box 3003
Lancaster
Pennsylvania 17604-3003
______________________________
Office telephone:   717-291-4135
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Home telephone:    717-560-0486
http://www.fandm.edu/rthomas
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