The elusive, giant beasts left a legacy 180 million years ago that can now be seen at Pipe Spring National Monument near Moccasin, Ariz., along the Utah border. This monument preserves an historic fort and structures built by Mormon pioneers during their settlement of the Southwest.

"At many localities, dinosaur footprints are mentioned in the literature, but no one has documented them," said Dr. Roger J. Cuffey, professor of paleontology in Penn State's College of Earth and Mineral Sciences. "There are more than 25 mentions of dinosaur prints in rocks of the same age as Pipe Spring, but only 7 or 8 have been adequately published."

Cuffey wasn't looking for new footprints at Pipe Spring. He was trying to take a photograph of a dinosaur footprint reported there for his undergraduate class in dinosaurs.

"In a 1988 booklet on where to go to see dinosaurs, Professor William Lee Stokes mentioned a natural cast of a dinosaur footprint at the visitor's center at Pipe Spring National Monument," said Cuffey. "The people at the park thought the cast was in storage, but asked me if I'd seen the dinosaur footprints in place on the mesa."

The footprints are on a mesa behind the ranch buildings, and are from a three-toed beast. They were only discovered in the mid-1990s. Two of the footprints are nearly side by side about 1.5 feet apart and the other footprint is 8 feet in front.

"I thought that these prints should be documented," said Cuffey. "And that they would be a good undergraduate project."

Two undergraduates, Maria Di Nardo and Bryan Herzing, who have both since graduated, worked on identifying and documenting the footprints for senior theses. Their literature search turned up a sizeable number of documented prints from the same period -- the early Jurassic -- in Connecticut and Massachusetts, but very little about footprints in the Navajo sandstone in the southwest.

"The trackway was laid down at the base of the orange Navajo sandstone at a time when that area was two or three days walk -- for a dinosaur -- from the shoreline to the west," said Cuffey. "The area was a desert created by wind-blown sand coming from the east, although there would have been a few small ponds of water between dunes for drinking."

The Penn State scientist and his students compared the Pipe Spring footprints with outlines of other dinosaur footprints found elsewhere to try to identify the animal that made them. He is fairly certain that they were made by a theropod, and most probably the kind known as Eubrontes.

"Because of the 8-foot length of the stride, this was a medium to large dinosaur," said Cuffey.

The theropods include both the enormous Tyrannosaurus Rex and the now famous velociraptors as well as some smaller scavenger dinosaurs and medium-size carnivores.

"One thing we did find out, was that the nice, clear outline drawings of dinosaur prints are rather difficult to match to the ragged and somewhat blurred edges of the actual footprints," said Cuffey. "A precise identification at this time is therefore elusive."

While the exact pedigree of the dinosaur tracks is still unknown, they should be available for viewing for quite a while. Currently, the Pipe Spring National Monument personnel go up every few months to sweep away the fine gravel that periodically blows across and obscures the prints. Cuffey has suggested to the National Parks Service that a fence or railing be installed so that the footprints can be viewed, but no one can inadvertently step on or damage them.

Note: If no author is given, the source is cited instead.

• Dinosaurs
• Paleontology
• Human Evolution
• Early Humans
• Tyrannosaurus Rex
• Early Climate

• Trace fossil
• Hadrosaurus
• Paralititan
• Brachiosaurus
• Stegosaurus
• Fossil