Time Traveling to the World's Largest Dinosaur Trackway

Yesterday, my daughter Aubrey and I went way, way, way back through the wilderness of time, actually to 150,439,697 years ago when I was still a twinkle in my mama's eye, to Jurassic Park times.

Looking out the dim portal of my handy time-travel machine, a cramped and clunky contraption designed in the mind of HG Wells, we glimpsed giant sauropods plodding across a muddy beach along the edge of a shallow inland sea, now called Dinosaur Lake, that washed emerald tides against a forest of towering tropical conifers and huge ferns.

Look! Look at that pair of Apatosaurs on the right! Moving in tandem, the two gigantic beasts lifted graceful necks into the sunshine, warily looking left and right at smaller theropods, three-toed, bipedal monsters like Allosaurus that pranced across the sloppy beach in search of meaty prey.

Okay, so my imagination runs amok sometimes. But the truth of those observations is based on the ancient evidence left in a bed of sandstone straddling the edges of the Purgatoire River in southeastern Colorado.

The river twists across the broad bottomland of Picketwire Canyon, an arid place of stairstepped slopes topped with varnished sandstone cliffs, rattlesnakes and bull snakes coiled beneath shady boulders, the etched scribblings of vanished Americans on leaning rock walls, and, above the land, a blaze of omnipresent sunlight that desiccates living things.

On both banks of the meager river is what is now called the largest dinosaur trackway in the world, with over 1,900 fossilized footprints in over 130 separate trackways on gray limestone bedrock. Most of the trackways were made by massive dinosaurs, trampling the muddy beach or walking side by side in a westerly direction. This parallel movement indicates herd behavior. In contrast, the prints of the carnivorous therapods are randomly scattered around, indicating that these critters were possibly looking for someone to crunch.

While we can go to museums and see the skeletal remains of dinosaurs reconstructed on pedestals and much can be discovered about these long-extinct creatures that shared our planet, the Picketwire Canyon track site offers a look at the elusive behavior of the dinosaurs. It allows us to ponder with more certainty what made these animals tick and let's us wonder why were they walking west on that muddy beach.

This image on the south bank of the Purgatoire River shows Aubrey's shadow cast across a sauropod trackway and in the upper right corner are the trampled tracks of a dino herd. The right side of the tracks in this photograph are obscured by mud and debris from flash flooding last summer. Mud also fills the 18-inch-wide footprints in the obvious left-trending trackway.

Aubrey's shadow falls across dinosaur tracks at Picketwire Canyon dinosaur trackway, the largest trackway in the world with almost 2,000 individual dino tracks. Photo © Stewart M. Green