North America is one of the largest continents, currently spanning 23 countries and more territories. The environment has changed much since its splitting from other landmasses, and is home to many fossil formations and fauna.
Precambrian[]
The oldest rocks on earth date back to 4.3 billion years ago and they are found in northern Canada.
Cambrian[]
The Burgess Shale in Canada is a very well preserved fossil formation that preserves fossils of Pikaia, Anomalocaris and many other organisms.
Ordovician[]
The Ordovician is known all over the United States many fossils of Orthocones and other organisms can be found.
Silurian[]
During this time period sharks were starting to evolve and fossil from Wisconsin, Iowa and Pennsylvania have preserved fossils of brachiopods, mollusks and other marine life.
Devonian[]
Dunkleosteus was the top predator of Devonian Ohio.
Carboniferous[]
Hylonomus of Canada was one of the first animals to crawl on land followed by Petrolacosaurus.
Permian[]
Synapsids like Dimetrodon and Edaphosaurus dominated Oklahoma, New Mexico and Texas.
Triassic[]
The oldest dinosaur fossils are from fragments from the Pekin Formation in North Carolina. The Cooper Canyon Formation in New Mexico has produced fossils of Camposaurus, Chindesaurus, Daemonosaurus, Gojirasaurus and Tawa. These were some of the first dinosaurs to live.
Jurassic[]
In the Early Jurassic the Kayenta Formation was ruled by the theropod Dilophosaurus, the ankylosaur Scutellosaurus and the prosauropod Sarahsaurus. Fossil footprints of dinosaurs known as Kayentapus and Grallator are known as well. In the eastern United States the prosauropod Anchisaurus and the theropod Podokesaurus ruled Connecticut and Massachusetts.
The late Jurassic period was home to the Morrison Formation in the western United States. It was ruled by the sauropods Apatosaurus, Supersaurus, Smitanosaurus, Diplodocus, Galeamopus, Haplocanthosaurus, Camarasaurus, Brachiosaurus and Maraapunisaurus. The ornithopods Camptosaurus, Dryosaurus, Uteodon and Nanosaurus. The thyreophorans Stegosaurus, Gargoyleosaurus and Hesperosaurus. And the theropods Allosaurus, Ceratosaurus, Fosterovenator, Hesperornithoides, Koparion, Marshosaurus, Saurophaganax, Tanycolagreus and Torvosaurus.
Cretaceous[]
In the Early Cretaceous dinosaurs continued to dominate both western and eastern North America. Theropods included Yurgovuchia, Utahraptor, Acrocanthosaurus, Deinonychus, Geminiraptor and Moros. Sauropods included Astrodon, Astrophocaudia, Sauroposeidon, Abydosaurus and Venenosaurus. Ornithopods included Eolambia, Tenontosaurus, Iguanacolossus, Planicoxa and Hippodraco. Thyreophorans include Sauropelta and Gastonia.
As the dinosaur diversity rapidly swelled up North America was split into two continents called Laramidia and Appalachia. These were divided by the Western interior seaway and in present day Kansas many marine life was dominating the area such as Elasmosaurus, Tylosaurus, Dolichorhynchops and Mosasaurus. There was also the pterosaur Pteranodon as well. As well as Ichthyornis and Hesperornis two diving birds.
About 76 million years ago as the Cretaceous was nearing its end dinosaurs were dominating every where in North America. They included Qiupalong, Eotrachodon, Titanoceratops, Utahceratops, Parasaurolophus, Prosaurolophus, Agujaceratops, Aquilarhinus, Saurornitholestes, Daspletosaurus, Gorgosaurus, Gryposaurus, Hypacrosaurus, Kosmoceratops, Lambeosaurus, Zuul, Xenoceratops, Corythosaurus, Velafrons, Brachyceratops, Brachylophosaurus, Naashoibitosaurus and Maiasaura.
At the end of the dinosaur age dinosaurs were still dominant but these were Tyrannosaurus, Triceratops, Edmontosaurus, Ankylosaurus, Alamosaurus, Anzu, Dakotaraptor. Thescelosaurus and Trierarchuncus in the Hell Creek Formation.
About 66 million years ago an asteroid struck the Chicxulub region in Mexico marking the end of the dinosaur age.
Paleocene[]
After the dinosaurs died out mammals took over and Paleocene North America includes birds, early horses and small mammals.
Eocene[]
Marine Mammals Basilosaurus and Dorudon lived in present day South Carolina and Alabama. They ate horses and marine life.
Oligocene[]
About 27 million years ago the La Garita caldera in Colorado violently exploded.
Miocene[]
The Gray Fossil Site in Tennessee has yielded a Rhino, a Tapir, Pristinailurus, a Mastodon and an Alligator.
Pliocene[]
Megalodon teeth have been found all over the United States.
Pleistocene[]
The first humans entered North America 14,000 years ago. At the same time North America was ruled by life such as Columbian and Woolly Mammoth. Saber tooth cats and Dire Wolves were common in California as well as Ground sloths.