I recently found some Astarte/Tridonta (mostly A. elliptica) shells which are almost certainly subfossil dating from the last ice age, but in almost perfect condition, complete with periostracum. I allowed the first one I found (unfortunately the only A. borealis) to dry out, and the periostracum flaked off immediately, as soon as the shell was dry. I have kept the subsequent finds in the clay and brackish water in which I found them, and would like to know the best way of preserving these, bearing in mind that they are probably subfossil and I particularly want to preserve the periostracum. I have been advised by a leading expert in ice-age molluscs in the UK where I live that the best preservation method is to use gum tragacanth as it is water-soluble and can easily be removed at a later date. He has had great success with this. But as I have a number of shells, I would also like to know of any alternatives that I could try so that I am not relying on one method. I know this has been discussed before (particularly in April 2002 under the subject of "oiling shells"), and from what I have read, parafin seems to be the best bet for preserving periostracum, though I do not really want to introduce any foreign substance if it is not completely necessary, particularly in case they were to be subsequently used for research or as museum exhibits. If I use parafin, would the shells need to be completely dry first? I doubt if the periostracum would survive complete drying. The shells have somehow been preserved buried in clay for thousands of years, and possibly more recently in brackish water, and I am wondering if there is some way of replicating this natural method of preservation for at least a short period of time. Would keeping the shells immersed in saline solution (in glass or plastic tubes so they could still be seen) preserve the periostracum? Sarah Longrigg ---------------------------------------------------------------------- [log in to unmask] - a forum for informal discussions on molluscs To leave this list, click on the following web link: http://listserv.uga.edu/cgi-bin/wa?SUBED1=conch-l&A=1 Type your email address and name in the appropriate box and click leave the list. ----------------------------------------------------------------------