Epoch

You may wish to consult Epoch (disambiguation) for other, similarly-named pages.

An epoch was, according to Bernice Summerfield, a division of time. (AUDIO: The Temple of Questions ^[+]Loading...["The Temple of Questions (audio story)"]) When Peri Brown suggested that horseshoe crabs were from space, the Sixth Doctor quickly corrected her, stating that the Cambrian Epoch in which they originated made them just as terrestrial as she was. (PROSE: Blue Box ^[+]Loading...["Blue Box (novel)"])

Behind the scenes

In actuality, the Cambrian was a period, not an epoch. As for horseshoe crabs, their earliest fossils only date back to the Ordovician period.