From the Museum Archives: Dinosaurs in our coal mines |

From the Museum Archives: Dinosaurs in our coal mines

Paul Knowles/Museum of Northwest Colorado

Believe it or not, dinosaur footprints are occasionally found clinging to the ceiling of coal mines all over the world. But why?

During the late Cretaceous Period — roughly 65 to 75 million years ago — Northwest Colorado consisted of a large swamp on the shores of a huge inland sea. This long-extinct shoreline produced vast coal seams that are today one of the largest economic drivers in Northwest Colorado.

Coal originates from the thick layers of highly organic ground, called peat, found in ancient swampy forests. As dinosaurs foraged these swamps they would inevitably leave behind their footprints in the soft ground. If the timing was just right, a flood would quickly fill in the fresh footprints with silt and sand and then left alone.

Over a period of millions of years these footprints would then become buried deep in the earth. The swamp peat underneath them would slowly become compressed and heated until it eventually became a layer of coal. At the same time, the silt and sand that filled the footprints would become a layer of sedimentary rock.

Then, when the coal seam is one day extracted by coal miners, a natural-cast footprint of an extinct dinosaur is left clinging to the mine ceiling as though the creature was still standing directly above. Sometimes dozens of tracks are found and can even include signs of a foraging in a circle around a tree.

These fascinating footprints are actually considered a mine hazard and are usually removed to prevent them from falling on the miners below. So in essence, you could still be maimed by a dinosaur even today!

This particular footprint — donated in 1968 by Agnes and Dick Miles — is on display in the Museum of Northwest Colorado. It was found hanging from the ceiling of a coal mine located south of Hayden, 17 miles east of Craig. It is believed to have been made by a member of the Hadrosaur, or duck-billed, family of dinosaurs. Their fossils are found throughout North & South America, Antarctica, Asia and Europe and range between 65 to 75 million years old.

Paul Knowles is assistant director of the Museum of Northwest Colorado. To learn more, drop by the Museum of Northwest Colorado at 590 Yampa Ave., or visit the museum’s Facebook page,