Paleontology in Arizona

This sea was still in place during the Cambrian period of the Paleozoic era and was home to brachiopods and trilobites, but it withdrew during the Ordovician and Silurian.

Sea levels began to rise and fall during the Carboniferous, leaving most of the state a richly vegetated coastal plain during the low spells.

Jurassic Arizona had a drier climate and was covered by sand dunes where dinosaurs left behind footprints.

During the Cretaceous, part of eastern portions of the state were covered by the Western Interior Seaway, home to marine reptiles, including plesiosaurs and turtles.

Most of Arizona was dry land during the Cenozoic era when the state was inhabited by wildlife including camels, horses, mastodons, and giant ground sloths.

Brachiopods, trilobites and other contemporary marine life of Arizona left behind remains in the western region of the state.

[1] During the Late Triassic, this area was being drained by channels of water flowing toward Pangaea's western coast.

[4] At the time of the Dockum Group's deposition, about 220 million years ago, Arizona had a very similar environment to that of nearby Texas.

Chindesaurus is notable for providing an evolutionary link between the local fauna and the most primitive known dinosaurs such as Eoraptor and Herrerasaurus, which are found in South America.

[12] During the Pleistocene, the local animal life included camels, mastodons, rodents, and giant sloths.

[1] At some point in the Pleistocene, mastodons were mired at the San Pedro Valley marsh site, not far from a salt lake.

Zuni creation stories contain considerable parallels to modern science's understanding of earth's history.

Zuni mythology describes these early people as incompletely human, having bulging eyes, ears like bats', webbed toes, wet skin and tails and living in caves.

The Sun's Twin Children feared that the vulnerable ur-people would be killed by the monsters before they could become "completed" people.

So, protected by magic shields, they armed themselves with rainbows and launched arrows made of lightning to kill the monsters.

Their lightning arrows sparked huge fires that dried up the water and baked the mud solid, making the world safe for the pre-human people to finish evolving into modern humans.

The author expressed deep concern about the future prospects of the fossils because many people were taking specimens both small and large.

Charles W. Gilmore visited the Grand Canyon area during the 1920s to collect specimens of these footprints for the Smithsonian Institution.