Quaternary Period Pecten gibbus Neptunea tabulata CENOZOIC ERA (Age of Recent Life) Tertiary Poriod Calyptraphorus velatus Venericardia planicosta Cretaceous Period Scaphites hippocrepis Inoceramus labiatus MESOZOIC ERA (Age of Jurassic Period Perisphinctes tiziani Nerinea trinodosa dieval Life) Triassic Monotis subcircularis Period Trophies subulatus Permian Leptodus americanus Parafusulina bosei Period Pennsylvanian Period Dictyoclostus americanus Lophophyllidium proliferum Mississippian Cactocrinus muItibrachiatus Prolecanites gurley Period PALEOZOIC ERA Devonian Mucrospirffer mucronate (Age of Palm atolopus unicornis Ancient Life) Period Silurian Period Cystiphyllum niagarense Hexamoceras hertzerl Ordovician Bathyurus extant Tetragraptus fructicosus Period Cambrian Billingsella corrugata Period Paradoxides pinus PRECAMBRIAN Index fossilsIndex fossils