Part 1 of Essay
During a lot of things happened both geologically and biologically. The Cambrian Period was the first period of the Paleozoic Era, it lasted from 570 million years ago to 500 million years ago, 70 million years. It¹s very important because it corresponds with the firs t appearance of abundant fossils especially Trilobi ....

Part 2 of Essay
.... a large inland sea called the Saulk sea. Inhabiting this sea, and the other seas of the primitive world, were Trilobites and Brachiopods . Trilobites were three - lobed arthropods, unlike other arthropods Trilobites had primitive ,unspecialized appendages. Brachiopods are simple bi- valve shellfish that resemble clams. During the Cambrian corals and chrinoids emerged. Chrinoids are sea animals of the class chrinoidea like the sea lily and the feather star. The only plant life of the Cambrian per ....