Dinosaur and turtle tracks from the Laramie/Arapahoe formations (Upper Cretaceous), near Denver, Colorado, USA

Abstract

A large slab showing more than two dozen dinosaur footprints discovered in the Upper Cretaceous (Maastrichtian) Laramie or Arapahoe Formation near Denver, Colorado, represents the first significant find of dinosaur tracks in the greater Denver metropolitan area in more than a decade. The tracks are all of tridactyl bipeds and appear to be mainly attributable to theropod dinosaurs, although some may be attributed to ornithopods. The track-bearing slab is undoubtedly the highest concentration and best preserved example of small dinosaur tracks ever discovered in the Laramie Formation, and adds significantly to our understanding of the range of size and shape of small bipedal tracks in the Denver area during the latest Cretaceous. At another site, small vertebrate tracks attributed to turtles were recently discovered. They consist of very short wide tracks with deep claw impressions.