Hi all
 
     Last week's thread on fossil oysters and shell thickness made me think
     about one of my favorite bivalves, Flemingostrea subspatulata, an
     oyster found commonly in the Upper Cretaceous Ripley Formation in the
     Southeastern United States.  Although I have found numerous specimens
     throughout Alabama, the thickest are from a roadcut near Lumpkin,
     Georgia.  One individual, 12 cm long and 7 cm wide that I found at
     this site, had a shell thickness of 6 cm.
 
     As Andrew had mentioned, oysters and pectens have calcitic shells and
     are sometimes the only megafauna preserved intact.  A question that I
     have been meaning to ask is does anyone know of recent gastropods with
     calcitic shells?  In Ordovician deposits around Cincinnati, gastropods
     are common as internal molds.  An exception are species of the genus
     Cyclonema which are found intact and thought to have had a calcitc
     shell.  Also, if I am not mistaken, species of the genus Ecphora from
     Miocene and Pliocene deposits had calcitic shells.
 
     Just some food for thought from a guy that east raisin bran for
     breakfast.
 
 
 
     Michael Reagin
     Cleveland Heights, Ohio