at www.smithsonian.com/science-nature/what-killed-dinosaurs-utahs-giant-jur… … dinosaur boneyards are an interesting aspect of the geological record. One such can be found in a Utah quarry that is roughly an hour's drive from the small town of Price. It is one of the most dense concentrations of Jurassic dinosaurs in the world – it is reputed, and the jumble of bones is packed mainly with the remains of one predator species, Allosaurus fragilia – but why might this be so?
The pit is deep but three quarters of the remains come from that species. The remaing quarter of fossils come not just from herbivores but other carnivores too. This particular species grew up to 30 feet in length – but how did they manage to get there. The consensus opinion is that a prey victom became stuck in mud and predators went in to feast on the beast only to get stuck themselves. In turn the bleating of their cries attracted more and more carivores and these too, became stuck. Another theory is that it was a shallow lake or marsh and the dinosaurs were killed by poisonous water.
The quarry is currently being reinvestigated using modern scientific methodologies and treating site as a crime scene in order to get to the most likely explanation – were they killed as a result of a single catastrophe or as a result of noxious fumes or whatever over a long period of time.