"Riding the Dinosaur"

"Riding the Dinosaur"

One of the most informative phases of fossil research is the study of tracks and trails. Ancient prints provide scientists with important data on the physical structure of the animal, its lifestyle, and the environment in which it lived and died.

During the last Ice Age the area now enclosed within the prison yard of the Nevada State Prison in Carson City had been a prehistoric waterhole. The numerous well—preserved footprints serve to record the abundance of thirsty animals that came here to drink.

The fossil footprints became quite famous soon after discovery and were not overlooked by early—twentieth—century convicts. Those who entered the state prison were routinely greeted by fellow inmates with the remark that, for the next prescribed number of years, they were going to be "riding the dinosaur."

The prints were made nearly 50,000 years ago by a number of animal species, including deer, ground sloth, elephant, and several carnivores such as the wolf and the saber—toothed tiger. One can easily envision the wide berth given the waterhole when this great cat came to drink. Since no sign of violence is associated with the cat, it is likely that other animals were conveniently in short supply as it approached. Thus all it did was drink and wander off.

Several of the prints do record a battle, but this was between two great Ice Age sloths. The rock base, which was then mud, bears the impression of opposing feet, one of which is set deeper at the toes and the other at the heels. This suggests that one sloth was pushing as the other resisted. Close by is a broad depression indicating where a third sloth was squatting, perhaps to watch the fight. Very likely it was the female sloth for whom the males were battling, the winner to enjoy her charms.

Even the wind direction of that long—forgotten day is recorded. On the ridges of each large footprint sand was lodged against the extruded mud. The sand stuck to the footprints as the prehistoric wind blew the particles against the upturned ridges. This served as a perpetual record that the wind direction for the latter part of that day was from the southwest, probably in strong but short gusts.

With the expansion of the prison facilities the prison yard was eventually cemented over. Modern prisoners and prison staff as well are generally unaware of the underlying prints, and the phrase riding the dinosaur has long been forgotten. Although now hidden from view, this rock record of the past is at least protected from the forces of weathering, erosion, and human vandalism. A few plaster casts of some of the prints are on display in the Nevada State Museum in Carson City.

From the book: 
Our Fascinating Earth