Hi all,   Today at a flea market I purchased a small handful of shells found on the Kaloot (NL), where you can find fossil sharkteeth as well as fossil seashells (and other fossils). He assured me that at least some (if not all) are fossils, which is true: the Pliothyrina in the middle is extinct, so it has to be a fossil; and many of the astartes on the bottom seem to be fossilized too. But I'm not sure that all the shells are fossilized. Therefore I was wondering, does anyone know ho