Picketwire Canyon Ancient Lizard Trail (15 photos + 1 video)
The largest dinosaur footprint in North America is hidden among the ghosts and archaeological gems of this canyon. 
Picketwire Canyon is a shallow canyon in southeastern Colorado located on the Rio de Las Animas Perdidas en Purgatorio, or River of Souls Lost in Purgatory. The canyon is home to the ruins of Mission Delores, the remains of the Wineglass Ranch, owned by a prominent 19th-century ranching family, traces of the Santa Fe Trail, numerous Native American archaeological sites, and even a few ghosts of a lost conquistador party. 
But the real reason people visit Picketwire is to see dinosaur tracks along a large inland sea of the Jurassic period. 
Dinosaur Trail
Across about half a kilometer of limestone on either side of the river are 1,300 dinosaur tracks in 100 separate tracks. Most of the tracks belong to either Apatosaurus or Allosaurus. The Apatosaurus tracks are the most prominent and show evidence of herd behavior, with larger tracks on either side of smaller ones. 
The Allosaurus tracks are the tracks of a single animal hunting an Apatosaurus. One of them shows a distinct slide in the mud as the animal makes a sharp turn to avoid the Allosaurus. Recent removal of sediment on top of the tracks reveals the presence of multiple Allosaurus, which may have hunted together. The Allosaurus tracks show signs of animals approaching with long strides and breaking into a run. One of them even shows one of three Allosaurus "springing" toward the prey. This is the first set of tracks near the river. 
Cave paintings on nearby cliffs
There are other, older signs of dinosaur behavior that are not typically found in tracks. One area, called the "tramp zone," is a series of overlying tracks in an area that would appear to have been trampled. But upon closer inspection, long, circular grooves are visible in the ground. These are tail drag marks, which indicate mating behavior, since Apatosaurus had a stiff, vertical tail. 
These tracks are just part of the canyon's rich and haunted history. The River of Souls Lost in Purgatory gets its name and its ghosts from a Spanish expedition led by Francisco Leyva de Bonilla, a Portuguese captain in the service of Spain, and Spanish captain Pedro de Cazorla. 
They were initially pursuing Native American raiders, but stories of the mythical land of Quivira told by the Pecos Pueblo filled Bonilla's head with thoughts of glory.
Cazorla declared Bonilla to be committing treason against the Spanish crown and returned with some troops to Pecos Pueblo. 
Bonilla and his lieutenant, Antonio Gutierrez de Humana, were advancing toward the high plains of Colorado. Since Bonilla was Portuguese, Humana was reluctant to obey his orders, and one night they had a fight over a campfire. Bonilla was left motionless, his blood dripping from Antonio Gutierrez de Humana's dagger. 
The priests of the detachment, seeing Bonilla lying in a pool of blood, swore that they would not follow the murderer and would not give rights and communion to anyone who did so. Together with a small detachment, they returned to New Spain, leaving Humanya in command of a diminished but still determined detachment. Gold and glory were much more important to Humanya than sanctimonious priests! Humanya crossed the Raton Pass and burst into the crucible of the Comanche people. 
On the edge of a canyon of a small stream running through the plain, the Comanches surrounded the detachment at a place called La Matanza, or "Slaughterhouse," and drove them to the edge of the forest. Then they killed every single person. Having no priest to perform the rite of burial over them, their souls were doomed to wander the banks of this stream forever, and their mournful groans can still be heard in the surrounding gorges. 
