Find the Marker
The San Juan County marker is on the southeast side of the Edge of the Cedars State Park Museum at 660 W 400 N in Blanding. It highlights Comb Ridge, a 120-mile-long north to south-trending ridge from where Seitaad ruessi, the plant-eating ‘sand monster’ of Utah’s Navajo Sandstone, was discovered.
GPS 37°37’52.896”N 109°29’23.568”W
If you find yourself in the southeast corner of Utah, rolling along U.S. Highway 191 between the outpost towns of Blanding and Bluff, you’ll eventually pass through a great gap in the rock. It almost seems like a huge geologic wave of reddish rocks extending to either side, ridged pillows of whitish rock on top. This isn’t just any geologic feature, but Comb Ridge – the place of discovery for one of Utah’s rarest dinosaurs.
“The dinosaur Seitaad ruessi is unique to Utah,” says Dr. Randall Irmis, NHMU's chief curator and curator of paleontology. “In fact,” he adds, “only one specimen has ever been discovered, and that was at Comb Ridge.” This Early Jurassic dinosaur is categorized as a sauropodmorph, or a member of the broad family that includes long-necked, herbivorous dinosaurs like Diplodocus. Being an early member of the group, Seitaad was smaller – about the size of a large dog – and walked on two legs rather than all fours.
But how could a plant-eating dinosaur like Seitaad have survived in such an arid environment during the Jurassic? “We have geologic and paleontologic evidence showing there were spring-fed pongs in and among the sand dunes,” Irmis notes, “and these water sources were permanent enough that large conifer trees grew nearby.” The habitat was a combination of very dry sand dunes and wet oases that many animals relied on to survive. Perhaps, as paleontologists continue to explore Comb Ridge, another Seitaad – or even something new – might greet them in the prehistoric red rock.
Want to Go Farther?
Valley of the Gods is just down the highway from Comb Ridge.
Explorer Corps in Action