Tracks from half a dozen species of dinosaurs turned up in a southern Utah area popular with ATV riders. An area the size of a football field was closed to protect thousands of three-toed and other tracks, according to the Bureau of Land Management, which manages the property about 5 miles southwest of Coral Pink Sand Dunes State Park in Kane County.
"Some people knew the tracks were out there, but we didn't," BLM spokesman Larry Crutchfield told The Salt Lake Tribune for a story posted online Thursday. "But most people didn't even know they were riding over dinosaur tracks."
The tracks were laid down across dozens of layers of rock, revealing a geologic record like the pages from a book.
They include tracks of a sharp-toothed and clawed carnivore, a three-toed crocodile and a large plant-eating species.
BLM paleontologist Alan Titus said the latest track find is extraordinary for its accessibility and high concentration of footprints.
"A local ATV rider told me about the site and I had planned to go see them," Titus said. "But when I saw a picture of the site, I had to get out there. I had no idea there were so many."
Southern Utah is known for dinosaur fossils and tracks from the Jurassic period. These animals lived about 190 million years ago in a harsh desert that got intermittent deluges.
"You rarely find herbivores in a desert," said Martin Lockley, who heads the Dinosaur Tracks Museum at the University of Colorado at Denver.
The prints in the sandstone are at least 100 million older than the fossils being extracted in neighboring Grand Staircase-Escalante National Monument, said paleontologist Andrew Milner, curator at the Johnson Farm track site in nearby St. George.