Paleozoic Age

The Palaeozoic or Primary Era spans a period of time ranging from 542 million to 251 million years ago. The name Paleozoic, derives from the fact that, in the past, it was considered the first geological age. The Paleozoic covers a range of about 300 million years, giving rise to many forms of life, until the appearance of thecodonts, commonly believed to be the ancestors of dinosaurs.