mineral shell?

[paul monfils]

"Internal casts" of gastropod shells, and even bivalve shells, are a common type of fossil. It sounds like that is what you are describing.  The empty shell gets filled with sediment which eventually becomes bound together into a solid mass, while the actual shell, being made of much softer calcium carbonate, slowly dissolves away leaving the internal cast.

Some information on posting images can be found here:

<a href="http://www.seashell-collector.com/Html/acebordHELP.htm" target="_blank"><!-- m --><a class="postlink" href="http://www.seashell-collector.com/Html/acebordHELP.htm">http://www.seashell-collector.com/Html/acebordHELP.htm</a><!-- m --></a>

Even if you don't have your own homepaqe or website, many servers provide a certain amount of free webspace where you can post things. Otherwise you can try one of the free posting sites. If you are unsuccessful, email the image to me and I will post it for you.

Regards,
Paul  <span class="petit">--Last edited by Paul Monfils on 2008-05-24 22:55:37 --</span>