Baculites compressus Cobban 1951.
Matrix free section from a straight shelled heteromorph Ammonite. Where the iridescent shell has been removed the beautiful internal sutures are shown to perfection. A 'beauty'. These straight shelled Ammonites would have been powerful swift swimmers.
Upper Cretaceous, Maastrichtian. Pierre Shale.
Cheyenne river, Bridger, Meade County, South Dakota, USA.
Ammonite : 7.5 cm diam.
