Bivalves 1 2 3
Bivalve fossils are not as common and not as diverse as gastropods. They are most often found as pyrite casts in the accumulations on the beach. The shell is usually missing. This is due to wave action. However when fresh slips occur they can be found with their original shell still largely intact. Very occasionally they are preserved on phosphatic nodules or on or in septarian cement stones. Unless the shell is infilled with a substance that helps to retain the calcium content of the shell they do not preserve well. So the shell needs to be associated with pyrite, phosphatic material or cement stone to stand any chance of consolidated preservation. If the shell is not in contact with these substances it is often decalcified in the clay. If this is the case then on contact to a drying atmosphere the shell soon crumbles away.
Astarte filgera
Astarte rugata
Astarte sp
Astarte sp.
Striarca wrigleyi
Abra splendens
Cuspida inflata
Ledina amygdaloides