Purgatoire River track site
The Purgatoire River track site, also called the Picketwire Canyonlands tracksite, is one of the largest dinosaur tracksites in North America. It is located on public land of the Comanche National Grassland, along the Purgatoire (“Picketwire”) River south of La Junta in Otero County, Colorado. Since 2001, the area has also yielded discoveries of dinosaur bones.
The tracksite is far from paved roads, but accessible to the public by hiking on foot, by mountain bike, or by horseback. Motorized vehicle access is restricted to tours conducted by the US Forest Service.
The more than 100 trackways, made up of more than 1300 individual footprints, were made by both biped and quadruped dinosaurs. The tracks occur in limestone of the Jurassic Morrison Formation. The site is believed to have been the shore of a large freshwater lake at the time the tracks were made.
- Martin Lockley, Karen J. Houk and Nancy K. Price, "North America's largest dinosaur trackway site: Implications for Morrison Formation paleoecology", Geological Society of America Bulletin, October 1986, v.97, n.10, p.1163-1176.
- Bruce A. Schumacher, “To Resurrect a Brontosaur”: Picketwire Canyonlands Sauropod Excavation.
- US Forest Service, Picket Wire Canyonlands - guided auto tour general information
- US Department of Agriculture, Forest Service 
- US Department of Agriculture, Forest Service, Picketwire Canyonlands dinosaur tracksite
- US Department of Agriculture, Forest Service, Picketwire Canyonlands dinosaur tracksite - life at dinosaur lake.
- Bruce A. Schumacher, Paleontological treasures of the Picket Wire Canyonlands, a glimpse into the Purgatoire River valley, Comanche National Grassland, southeastern Colorado, Geological Society of America, annual meeting, 2004, Paper 177-4.
- Schumacher, B. A. 2008. The Last Chance Site, a new sauropod quarry from the upper Jurassic Morrison Formation, southeastern Colorado - in (Choate, J. and Farley, G., eds.) Unlocking The Unknown: Papers Honoring Dr. Richard J. Zakrzewski, Fort Hays Studies, Special Issue Number 2, Fort Hays State University, p. 77-88.