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Three trackways of dinosaur footprints. The middle one was made by a bipedal dinosaur, and those on both sides by quadrupedal dinosaurs (sauropods). The rocky substrate consists of sandstones formed on a beach or coast at low tide. The substrate was originally wet and firm, but deformable. The direction of movement of the dinosaurs was to the left.
Site of dinosaur footprints of Cal Orcko, in Sucre, where more than twelve thousand prints have been found on numerous trackways in this wall of limestone and sandstone inclined at about 70 degrees, 1200 m long, and 80 m high. Researchers have found almost 300 ichno species on this exposure.
“Brontosaur bulges." Mid-way through the picture we can observe four bulges in a sandstone layer, depressing downward the underlying layers. These have been interpreted as a dinosaur trackway viewed in cross-section. A large sauropod left these “underprints" by deforming soft sediment while walking. Very specific conditions (e.g, sediment cohesiveness, rate of sedimentation, exposure vs submergence) are necessary for the preservation of footprints in the rock record. Scale bar is 40 cm long. Photo taken at Dinosaur Ridge, Golden, Colorado.
The Dinosaur Ridge Tracksite, in Golden, CO, preserves two main types of dinosaur footprints. Both are tridactyl (with three toes). They have been colored in with charcoal to enhance their visibility. The tracks with a wider aspect and thick toes were made by ornithopod dinosaurs. They were left by animals of different sizes (possibly adults and juveniles). The narrow-toed tracks were made by theropods. See if you can recognize the different tracks. This outcrop exposes the surface of a sandstone bed in the Lower Cretaceous South Platte Formation of the Dakota Group.