Map by Ry Hagen

Precambrian (541mya-4.6bya)

ryhagen301_1 — 2025-02-24 13:13:33 UTC

The first found Precambrian fossil, was an organism called "Charnia," it was found in Charnwood Forest, in the UK. A teenage boy discovered it, and it's important that it was found in rocks considered older than the Cambrian period, which was first thought to be the earliest era of life.

Paleozoic Era

ryhagen301_1 — 2025-02-24 13:17:33 UTC

The first fossils to show the beginning of the Paleozoic Era are Trilobites, this period is called the "Cambrian Explosion" because of the rapid diversity of life forms at that time.

Mesozoic Era

ryhagen301_1 — 2025-02-24 13:23:36 UTC

The first fossil known to be from the Mesozoic Era is likely a dinosaur called Eoraptor, which showed up in the Triassic period, marking the beginning of the Mesozoic era. This dinosaur is considered one of the earliest known dinosaurs in the fossil record

Cenozoic Era

ryhagen301_1 — 2025-02-24 13:30:12 UTC

The first fossil mammals found from the Cenozoic Era would likely be considered to be the "Eomaia", which appeared in the Paleocene epoch, the first period of the Cenozoic, shortly after the extinction of the dinosaurs; however, it's important to note that mammals existed long before the Cenozoic, with the earliest mammal fossils belonging to the late Triassic period, like "Morganucodon