List of index fossils

Index fossils (also known as guide fossils or indicator fossils) are fossils used to define and identify geologic periods (or faunal stages). Index fossils must have a short vertical range, wide geographic distribution and rapid evolutionary trends. Another term, Zone fossil is used when the fossil have all the characters stated above except wide geographical distribution, they are limited to a zone and can't be used for correlations of strata. [1]

FossilScientific NameTime PeriodMillion Years Ago
Calico scallop

Argopecten gibbus
Quaternary Period1.8 million years ago
Neptunea tabulataQuaternary Period1.8 million years ago
Viviparus glacialisTiglian (Early Pleistocene)0.5 million years ago
Calyptraphorus velatusTertiary Period
Venericardia planicostaEocene |

Scaphites hippocrepisCretaceous Period145 to 66 million years ago

Inoceramus labiatusCretaceous Period

Perisphinctes tizianiJurassic Period201.3 to 145 million years ago
Nerinea trinodosaJurassic Period
Tropites subbullatusTriassic Period145 to xxx million years ago
Monotis subcircularisTriassic Period

Leptodus americanusPermian Periodxxx to xxx million years ago
ParafusulinaParafusulina boseiPermian Period
Dictyoclostus americanusPennsylvanian Periodxxx to xxx million years ago
Lophophyllidium proliferumPennsylvanian Period
Cactocrinus multibrachiatusMississippian Periodxxx to 416 million years ago
Prolecanites gurleyiMississippian Period

Mucrospirifer mucronatusDevonian Period416 to 359 million years ago
Palmatolepis unicornisDevonian Period
Silurian Period359 to xxx million years ago
Tetragraptus fructicosusOrdovician Periodxxx to 509 million years ago
ParadoxidesCambrian Period509 to 500 million years ago
Billingselia corrugataCambrian Period
ArchaocyathidsLower Cambrian529 to 509 million years ago


  1. Index Fossils, from the US Geological Survey. Updated July 31, 1997.
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