Iguanodon tracks found on Dinosaur Ridge. Large tracks are believed to be those of an adult.  Smaller tracks are those of a juvenile.

A Geological Tour of Denver, Golden, and Colorado's Front Range

By Jack Barkstrom

Tracks along the shore...

Stegosaurus, Colorado's state fossil, was first discovered in Colorado on Dinosaur Ridge in 1877. At a quarry named Saurian No. 5, Arthur Lakes, working for Yale University Professor O. C. Marsh, found the bones of both Stegosaurus armatus and Diplodocus lacustris, a brontosaur.  Despite that discovery, few footprints of Stegosaurus have been found on Dinosaur Ridge. One reason may be that the terrain it liked did not preserve tracks as well as the wetter ground found along beaches, where Iguanodons roamed.[1]

Dinosaur Ridge 100 million years ago offered unusually favorable conditions for track preservation.  At the same time, these conditions lasted, or were repeated, over a considerable period of time, for there are at least seven separate levels where tracks have been discovered.[2]

Not far from Dinosaur Ridge, at Fossil Trace Golf Course, in Golden, there is an impression of a Triceratops footprint.  Regionally, the first Triceratops discovery was made in Denver in 1887, near Federal Boulevard.  While the physical distance between the Iguanodon tracks found at Dinosaur Ridge and the Triceratops tracks found at Fossil Trace is just a few miles, the time difference is immense.  The Fossil Trace impressions were made some 30 million years later, when the Cretaceous Sea had retreated from Utah and was receding from Colorado as well.[3]

Footnotes
(1) Peter J. Modreski, "Geochemical and Mineralogical Studies of Dinosaur Bone from the Morrison Formation at Dinosaur Ridge," in "The Mountain Geologist," Volume 38, Number 3, Rocky Mountain Association of Geologists, (Denver, CO July 2001), p. 115;
Martin Lockley, "Fossil Footprints of the Dinosaur Ridge and Fossil Trace Areas, 2nd ed." Friends of Dinosaur Ridge and the University of Colorado at Denver Tracker Research Group, (Golden, CO 2003), p. 12.
(2) Lockley, "Fossil Footprints of the Dinosaur Ridge and Fossil Trace Areas," p. 38.
(3) Lockley, "Fossil Footprints of the Dinosaur Ridge and Fossil Trace Areas," pp. 52 & 54.