The Cambrian Explosion describes the sudden appearance in the fossil record of diverse, advanced marine life without any clear evidence of ancestors.

Below, you will find an infographic depicting the placement of certain fossils, from the GRI collections, within the Cambrian and Precambrian layers of the geologic column.

* The above graphic represents the lowest appearance in the geologic column of the represented phyla, shown by the base of each vertical bar. GRI’s fossil specimens pictured in the graphic are all Cambrian examples belonging to the respective phyla, but were not necessarily found at the very base of the phylum’s stratigraphic range.

Further Reading

• The Cambrian Explosion, by Raul Esperante

• Polyphyly and the Cambrian Explosion, by L. James Gibson

• Cambrian Explosion and Darwin’s Doubt, by L. James Gibson

• Trilobite Explosion, by L. James Gibson

• Cambrian Complexity, by L. James Gibson

• The Cambrian Explosion at Qingjiang, by L. James Gibson

• Famous Fossils From a Mountaintop, by Harold G. Coffin

• The Precambrian, by Benjamin L. Clausen: Part 1, Part 2, Part 3