Stock Photo: Extinct gastropods and mollusks: Ammonites Rhotomagensis, Scaphites aequalis, A. varians, Hamites rotundus and Turrilites costatus. Handcoloured lithograph by an unknown artist from Dr. F.A. Schmidt's "Petrefactenbuch," published in Stuttgart, Germany, 1855 by Verlag von Krais & Hoffmann. Dr. Schmidt's "Book of Petrification" introduced fossils and palaeontology to both the specialist and general reader.