>Yes, no doubt it is eroded, but I can't quite understand the
>dislocation of the line as it was
>melted.
>
>If you grind a shell it will not look like this, the shoulder line
>will not be displaced.

Hi Marcus

Remember that Ellobium aurismidae, in addition to being thickshelled,
has a well-developed periostracum. In this species the periostracum
is not resorbed as the shell grows; instead the new shell is
laid-down over it, trapping it between the previous whorl & the next.
This will leave a distinct pseudosuture if the shell is eroded away
at the suture, and because the shell is conical in section the
pseudosuture (for want of a preexisting term) will "dip" abapically
over the worn area.

In exactly the same way ammonite sutures become pseudosimplified if
the fossil shell is ground down.
--
Regards
Andrew

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