mystery fossil

[Ken Kinman]

Hi Tim,
     Are you sure it is enamel?  The U-shaped "tube" vaguely reminds me of a tube-dwelling annelid or a wormy mollusc.  The denticles could perhaps help deter predators or help anchor the tube in sediment.  If I had a set of the Treatise on Invertebrate Paleontology available, I would look at fossil polychaetes or solengasters to begin with.  I suppose it could be a fake, but maybe it is just something unfamiliar (or one of many fossil problematica).  Will look at it again tomorrow when I have time.
    ----Cheers,
              Ken Kinman