Mystery Fossil

Data: Fossil was lacated in the woods around Dickson Tennessee

Send Ideas to: Brett




  • Your fossil appears to be the internal casting of a ? possible ammonite. The shells fill up with sediment and solidify and the shell can get worn away just leaving a beautiful casting such as yours. ... Avril B.

  • While the fossil is an internal mold, it is not an ammonite (no chambers). It reminds me of a freshwater snail like a ram's horn....John J.

  • The coiling is not correct for a planorbid (ramshorn) gastropod, which is sinistral-hyperstrophic, giving the misleading appearance of being dextral.
    The rocks there are too old to be an ammonite, which appeared in the Triassic. The oldest ammonoids, of which the ammonites are the youngest group, appeared in the Devonian.
    This shell is an internal mold or steinkern, possibly a nautiloid in which the septa have not been preserved (rather unlikely) or miore probably a monoplacophoran or a bellerophontoid gastropod, both of which have bilaterally-symmetric shells. ...Andrew G.

  • it surely looks like a bellerophontid. Especially since Andrew said the rocks are too old for ammonites....
    Cheers, ...Sven

  • Dickson County has lower Carboniferous (Mississippian) rocks for the surface. The lack of chambers strongly suggests a bellerophont "monoplacophoran". Bellerophonts were planisirally coiled shells, probably including some early gastropods, some relatives of other living groups, and some extinct groups. ... Dr. David C.

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