Upper Cretaceous Period- C. 100-66 Million Years Ago Order to which the fossil belongs: Ammonitida Name of which the family belongs: Desmoceratidae Informal name of the fossil: Ammonite A nice example of pair of well preserved, polished Desmoceras Latidorstatum ammonite halves, which has been cut down the middle to show the internal chambers of the fossil. Ammonites are a form of ammonoid which are distinguished by their complex suture lines. They evolved very rapidly to produce numerous species and genera, but it was during the Late Cretaceous period that the ammonites and other marine groups, like belemnites, and terrestrial groups, like dinosaurs became extinct. The name ammonite, was inspired by the spiral shape of their fossilized shells, resembling tightly coiled rams’ horns. Many ammonoids probably lived in the open water rather than at the sea bottom, this is due to the fact that their fossils are often found in rocks that were laid down under conditions where no bottom-dwelling life is found. They are typically evolute with the inner whorls exposed, but some are commonly stout and more involute and strongly ribbed with pronounced tubercles. A beautiful example of a pair of polished Ammonite halves, with fine detail. It has slight iridescence to shell and some calcite infill. Size: 50mm x 62mm