List of index fossils

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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]

Fossil Scientific Name Time Period Million Years Ago
Calico scallop 02.jpg
Calico scallop

Argopecten gibbus
Quaternary Period 1.8 million years ago
Neptunea tabulata Quaternary Period 1.8 million years ago
Viviparus glacialis - Rosmalen - Late Tiglian.jpg Viviparus glacialis Tiglian (Early Pleistocene) 0.5 million years ago
Calyptraphorus velatus Tertiary Period
Venericardia planicosta Eocene
Scaphites hippocrepis Cretaceous Period 145 to 66 million years ago
Inoceramus labiatus Cretaceous Period
Ammonit - Wüstenhaus.jpg
Perisphinctes tiziani Jurassic Period 201.3 to 145 million years ago
Nerinea trinodosa Jurassic Period
Tropites subbullatus Triassic Period 145 to xxx million years ago
Monotis fossil shells - Kiritehere beach.jpg Monotis subcircularis Triassic Period
Leptodus americanus Permian Period xxx to xxx million years ago
Parafusulina Parafusulina bosei Permian Period
Dictyoclostus americanus Pennsylvanian Period xxx to xxx million years ago
Lophophyllidium proliferum Pennsylvanian Period
Cactocrinus multibrachiatus Mississippian Period xxx to 416 million years ago
Prolecanites gurleyi Mississippian Period
Mucrospirifer mucronatus Silica Shale.JPG
Mucrospirifer mucronatus Devonian Period 416 to 359 million years ago
Palmatolepis unicornis Devonian Period
Silurian Period 359 to xxx million years ago
Tetragraptus fructicosus Ordovician Period xxx to 509 million years ago
BLW Trilobite (Paradoxides sp.).jpg Paradoxides Cambrian Period 509 to 500 million years ago
Billingselia corrugata Cambrian Period
Archeocyathids.JPG Archaocyathids Lower Cambrian 529 to 509 million years ago
Examples of index fossils


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