Fossil snail (Keeneia oculi). This is the fossil- ised shell of a gastropod (class Gastropoda). The gastropods are a group of molluscs which have one muscular foot and (usually) a coiled shell. Modern snails are gastropods. This gastropod lived during the Permian period, 250-290 million years ago. It is about 3.5 centimetres across. Found in New South Wales, Australia.