Geology During the Cambrian period major rock formations were forged. Many of these are still visible today, in the oldest parts of continents. Shallow seas spread over the landscape. The climate started out cool, even arctic in the north, but it became more moderate and lasted like that through the Ordovician. Animal Life: Fossils dating to the Cambrian are widespread, all in the seas. Life included: Coelenterates, protozoa, poriferans, molluscans, worms, echinoderms, trilobites, trilobitomorphs, achaocyathids, and brachiopods. Plant Life: Algae was the major forms of plant life. They secreted lime, helping in the formation of rocks.

A shrimp dating to the Cambrian Period

A trilobite fossil

Paleozoic Era: Cambrian Period