Fossil Hunting in Utah

Utah is a paleontological powerhouse. With rocks spanning over 500 million years of Earth history exposed across dramatic desert landscapes, the state offers fossil collecting opportunities ranging from Cambrian trilobites to Jurassic dinosaurs to Eocene lake fish. Vast tracts of BLM land make much of this accessible to the public.

Why Utah?

Utah sits at the intersection of incredible geology and public access. The state’s arid climate means little vegetation covers the rock, and erosion constantly exposes new fossil material. The Colorado Plateau, Great Basin, and Uinta Mountains each tell different chapters of life’s history.

The Wheeler Shale in the House Range is world-famous for its abundant, well-preserved Middle Cambrian trilobites — particularly Elrathia kingii, one of the most recognizable trilobites on Earth. The Morrison Formation, exposed across eastern Utah, has yielded some of the most important Jurassic dinosaur discoveries in North America, including the legendary quarry at Dinosaur National Monument. And the Green River Formation preserves an Eocene lake ecosystem with extraordinary detail, producing fish, insects, and plants.

Perhaps best of all, roughly 65% of Utah is federal public land, and BLM regulations allow casual collecting of common invertebrate and plant fossils for personal use — no permit needed.

What You’ll Find

Cambrian trilobites (~510-500 million years ago):

• Elrathia kingii — the iconic Utah trilobite, found in abundance in the Wheeler Shale
• Asaphiscus wheeleri — a larger, less common trilobite from the same formation
• Agnostid trilobites — tiny, blind trilobites often found on the same slabs
• Brachiopods and other Cambrian marine invertebrates

Jurassic dinosaurs and marine life (~200-145 million years ago):

• Morrison Formation dinosaurs including Allosaurus (Utah’s state fossil), Diplodocus, Stegosaurus, and Camarasaurus
• Marine Jurassic formations in western Utah contain ammonites and belemnites
• Dinosaur tracks in the Moenave and Kayenta Formations of southern Utah

Eocene lake fossils (~50 million years ago):

• Beautifully preserved fish (Knightia, Diplomystus, Priscacara) from the Green River Formation
• Insect fossils with remarkable wing detail
• Plant leaves and seeds

Cretaceous fossils:

• Ammonites and marine invertebrates from the Mancos Shale
• Late Cretaceous dinosaur and turtle remains from the North Horn Formation

Best Time to Visit

• Spring (April-May): Pleasant temperatures in the desert before summer heat arrives. Freeze-thaw over winter may have exposed new material.
• Early fall (September-October): Heat subsides, making fieldwork comfortable. Clear skies and low humidity.
• Avoid summer (June-August): Temperatures in the House Range and eastern Utah regularly exceed 100 degrees F. Heat exhaustion is a real risk when splitting shale in direct sun.
• Winter: Many collecting areas have rough dirt roads that become impassable with snow or mud.

Tips for Utah Collecting

1. Bring water — lots of it. Most collecting sites in Utah are remote desert with no services. Plan for at least one gallon per person per day, and more if splitting rock in the sun.
2. Use a flat pry bar and rock hammer. Wheeler Shale trilobites are found by splitting thin shale layers along bedding planes. A flat-bladed tool slides between layers better than a chisel point.
3. Check both sides of every split. When splitting shale slabs, the trilobite can end up on either the top or bottom piece — always inspect both surfaces.
4. Wrap specimens carefully. Trilobites in the Wheeler Shale are often delicate. Bring newspaper, paper towels, and small containers for your best finds.
5. Carry a GPS or detailed maps. Cell service is nonexistent in the House Range and many other Utah collecting areas. Know your route in and out before you lose signal.
6. Respect vertebrate fossil laws. If you find dinosaur bone, turtle shell, or any vertebrate material on federal land, photograph it, record the GPS coordinates, and report it to the BLM or a local museum. Do not collect it — it is illegal without a permit.
7. Visit U-Dig if you want a guaranteed experience. The commercial quarry is well worth the fee for families or first-timers. You will find trilobites — the only question is how many and how nice.
8. Pair fossil collecting with Utah’s parks. Many fossil sites are near spectacular national and state parks. Combine a day of collecting with visits to Capitol Reef, Goblin Valley, or Dinosaur National Monument.

Collecting Sites

Legal Rules for Utah

Key Geological Formations

• Wheeler Shale (Middle Cambrian)
• Morrison Formation (Late Jurassic)
• Green River Formation (Eocene)
• Mancos Shale (Late Cretaceous)
• North Horn Formation (Late Cretaceous-Paleocene)

Local Fossil Clubs & Museums

• Utah Friends of Paleontology
• Utah Geological Survey
• Natural History Museum of Utah
• Timpanogos Gem and Mineral Society