Miocene Mystery Revealed
After uncovering fossilized bones from tapirs, turtles and an elephant-like animal, the group hypothesized that the fossils uncovered had to be from the Pleistocene Epoch, between 15,000 to 30,000 years ago. While they were not uncovering any common ice age animals, their hypothesis was based on the fact that the fossils they found occur in Tennessee fossil deposits dated to the end of the ice age. It wasn't until TDOT environmental specialist Rick Noseworthy unearthed a portion of a skull, which Dr. Parmalee identified as that of an alligator or crocodile, that Pleistocene doubts began to rise. Eventually the Pleistocene hypothesis was eliminated entirely because scientists from the Illinois State Museum and North Dakota were able to identify several fossils from a Miocene rhinoceros skeleton. The particular genus, known as Teleoceros, became extinct in North America around 4.5 million years ago. After the Teleoceros discovery and identification, it became clear that this site was warmer, older and more unique than anyone had originally thought. After further excavation, the group was able to determine a more accurate time frame because they now knew, after recovering Teleoceros (believed to have existed between 4.5 million years ago and 17.5 million years ago), and another species, Plionarctos (a small tremarctine bear, which existed between 2 million years ago and 7 million years ago), that the age of the entire fossil collection was between 4.5 and 7 million years old.
Visiting the East Tennessee State University (ETSU) and General Shale Brick (GSB) Natural History Museum and Visitor Center at Gray Fossil Site allows one to visually journey back in time, more than 4.5 million years ago, to a Miocene land that would look more similar to the present-day continent of Africa than to present-day Tennessee. Many of the species unearthed from the site are familiar to us such as the rhino, "elephant" and camel; however, the exhibit shows that these animals are very distinct from of animals that exist today. Touring the exhibit hall is like a journey through time that showcases the change in animals and environment over the ages.
The Miocene is a geological epoch of the Neogene Period and extends roughly from 23 million to 4.5 million years before present day. The Earth morphed from the Oligocene Epoch through the Miocene and into the Pliocene before cooling into a series of ice ages. The Miocene Epoch often is referred to as the regional boundary between the warmer Oligocene and the cooler Pliocene, when no distinct global event took place. Many of the fossilized species unearthed from the Miocene have close relatives alive today.
Photographs Courtesy of the Natural History Museum