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Triassic · 251.9 – 201.4 Ma

Triassic fossil sites

Life recovered slowly from the Permian extinction. The earliest dinosaurs, mammals, and modern coral groups all appeared in the Triassic. Marine fossil sites favor ammonites and the first ichthyosaurs and plesiosaurs.

A golden Ceratites ammonite, its ribbed coil laid on a plain background
Photo: Dr. René Hoffmann, CC BY-SA 3.0, via Wikimedia Commons

The Triassic opens on an emptied world. The end-Permian extinction had removed most life, and recovery took millions of years. Into that space came the first dinosaurs, the first mammals, and the first pterosaurs. In the sea, ichthyosaurs and nothosaurs took the roles that earlier marine reptiles had vacated.

Triassic rocks are often red. Iron oxide formed in the dry Pangaean interior and stained the sandstones and mudstones that fill many basins. Those beds preserve reptile bones and trackways rather than shells. Marine Triassic rock is scarcer but yields ammonoids and the large ichthyosaurs that made the period famous.

The Triassic list runs to eleven entries. Eight are viewing sites and only two allow free collecting. Berlin-Ichthyosaur State Park in Nevada preserves ichthyosaurs where excavators found them. The Paleorrota area of southern Brazil produces some of the oldest dinosaurs known anywhere. Petrified Forest National Park in Arizona exposes the Chinle Formation, where whole logs of silicified wood lie across the desert surface.

11 fossil sites

Updated 3 August 2026

Life of the period

Three to know from the Triassic

You will not find all of these yourself. They are the animals and plants that make the period worth reading about.

  • A mounted ichthyosaur skeleton suspended in a museum gallery.
    Giant ichthyosaurShonisaurus

    Around 15 metres long, and Nevada's state fossil. Berlin-Ichthyosaur State Park preserves several individuals in the rock where they were excavated, left in place rather than removed to a museum.

    Carpenter, Kenneth, CC BY-SA 4.0

  • Two mounted early dinosaur skeletons in a museum display about dinosaur origins.
    Early dinosaurHerrerasaurus

    One of the oldest dinosaurs known, from roughly 231 million year old rock in Argentina. It stood about a metre at the hip. Dinosaurs spent their first 30 million years as a minor part of the fauna.

    Zach Tirrell, CC BY-SA 2.0

  • A mounted Coelophysis skeleton standing on a plinth in a museum gallery.
    Ghost Ranch theropodCoelophysis

    A quarry at Ghost Ranch in New Mexico produced hundreds of individuals stacked together, probably a mass death at a drying water hole. Few dinosaur bone beds anywhere have produced so many animals from one place.

    bryan, CC BY-SA 2.0

All Triassic sites

Frequently asked questions

What are the oldest dinosaurs?
The earliest widely accepted dinosaurs come from Late Triassic rocks in Argentina and southern Brazil, around 230 million years old. Herrerasaurus and Staurikosaurus are among them. They were small, walked on two legs, and were far from dominant at the time.
Why is so much Triassic rock red?
Iron in the sediment oxidized in a dry, well-drained setting. The result is the red beds that fill Triassic basins across North America, Europe, and Africa. Red does not mean the rock is barren, but it does mean the sediment settled on land.
Can I collect Triassic fossils?
Rarely at the sites in this guide. Eight of the eleven are viewing only, and several sit inside national parks where collecting is a federal offense. Read each page before you plan a visit.