Worland Field Office

Paleontology in the Bighorn Basin

RGDT visitors.
Tracing the dinosaur tracks.
College students working at the tracksite.
College student working at the tracksite.
The 260-plus million acres administered by the BLM are rich in fossils. Most public lands are simply those rejected by homesteaders as too steep, too dry, and too barren to support a family. What is unsuitable for agriculture is perfect for fossil discoveries.

Paleontologists have been collecting fossils in the Bighorn Basin since before 1880. Rocks in the Basin and along the flanks of the Bighorns and Absarokas range from about 600 million years to about three million years old, and all but one geologic period is represented.

The Bighorn Basin, and Wyoming in general, has yielded many kinds of fossils. The region is arid, so little soil or vegetation forms to obscure the exposures of bare rock. Also, when rain falls, it often does so violently and quickly erodes the surface, exposing more and more fossils.

Collecting. Much of the surface is administered by the BLM, so while hobbyists may collect petrified wood, invertebrates, and plant fossils, vertebrates are kept in the public trust through BLM's collecting permit process.

May I Collect Fossils? You may collect a variety of fossils on public lands, with certain restrictions. Special management designations restrict access and types of activities on some public lands. It is always a good idea to stop by the nearest BLM office to check on local conditions such as land status, fire danger, or road closures. On private lands, fossils may be collected only with the permission of the landowner.

Invertebrates - no permit is required to collect reasonable amounts of invertebrate fossils such as:

  • trilobites
  • brachiopods
  • ammonites

The invertebrate fossils you collect are for your personal use and enjoyment, and may not be bartered or sold. Please remember to leave some for the next collector, too.

Petrified Wood - you may collect:

  • up to 25 pounds of petrified wood, plus one piece, each day.
  • no more than 250 pounds in any calendar year without a permit.

You may not combine your allowance with another collector's allowance to obtain larger pieces of petrified wood. And you can't sell it without a special permit.

Other Plant Fossils - no permit is required to collect reasonable amounts of plant fossils such as leaves. They are for your personal use and may not be bartered or sold.

Vertebrates - vertebrate fossils may only be collected with a permit because of their relative rarity and scientific importance. They include not only bones and teeth, but also footprints, burrows and other traces of activity.

Vertebrate fossils are fragile and complex and permit applicants must be able to show a sufficient level of training and experience in order to collect them. In addition, all vertebrate fossils collected under a permit must be held in an approved repository.