Crassispira semicolonCrassispira semicolon is an extinct species of carnivorous sea snail, a marine gastropod mollusk in the family Pseudomelatomidae, the turrids and allies.Subspecies: † ''Crassispira semicolon chameryensis''DescriptionThe length of the shell attains 24.6 mm; its diameter 8.3 mm. It lived from roughly the Eocene period 47.8 - 41.3 million years ago, before having a last known appearance 3.60 - 2.59 million years ago, during the Cenozoic period.DistributionFossils have been found in Pliocene and Middle Eocene strata off Norfolk, Great Britain; also in the Paris Basin and the Loire Basin, France