[3] Both proposals will set the lower boundary close to 514.5 million years ago.
The International Commission on Stratigraphy has not named the fourth stage of the Cambrian yet.
In the widely used Siberian nomenclature stage 4 would overlap with parts of the Botomian and Toyonian.
[6] During Cambrian Stage 4, three families of trilobites were widely distributed: olenellids, redlichiids, and paradoxidids.
In particular, trilobites of the families Ollenellidae and Redlichiidae have been extinct in Laurentia and South China, respectively.