Natural Science Forum / Biology / Paleontology / May 2005

Hmmm.  What part of Tennessee was that found in?  Does the rock fizz when
exposed in a small area with hydrochloric acid?  It almost looks like boxwork,
calamine (zinc carbonate), or limonite (all of which can be found in tennessee).
If it doesn't fizz on exposure to acid, will it scratch a knife blade?  Will it
scratch a chunk of calcite?  Will it scratch your fingernail?  Also, if you
could post some higher resolution images, that would be helpful.  Bivalves are
common in many rocks in tennessee, so that isn't much help without knowing the
location where you found this specimen (perhaps you could also post some images
of the bivalves - sometimes, identifying associated fossils can narrow the
possiibilities).  Rotten chert is another possibility, or maybe even travertine,
as it looks like something found in a cave, or spring entrance (you can also
find similar rock at a contact spring emanating from an outcrop), or in a
weathered chert zone in soil residuum.  As for the possibility that it is a
fossil, it could be, but it is hard to say from these pictures.  If it is
associated with bivalves in tennessee, it is not too likely to be any kind of
'beak'.  One fossil that could conceivably be confused with a beak is an
orthocone cephalopod, which is very common in parts of tennessee.  Having said
that, if this is an orthocone, it is highly weathered.  It doesn't have the
characteristic segments of an orthocone, nor any apparent siphuncle.  Sorry that
I can't be much more help.  Of course, it is always best to actually have the
specimen in hand when examining it, but a higher resoltion image might help,
along with some detailed physical characteristics of the rock (hardness, whether
or not it is brittle, steak - the color of the powder if you crush a small piece
of it, such as rubbing it against a piece of unglazed porcelain, etc.).