Gray Fossil Site facts for kids
The Gray Fossil Site is a special place in Washington County, Tennessee, USA. It holds many fossils from about 4.5 to 4.9 million years ago, during a time called the Pliocene Epoch. This site was found by accident in May 2000 when workers were building a road near Gray, Tennessee. People quickly realized how important these fossils were. So, they decided to save the site for learning and research.
Today, the Gray Fossil Site is part of East Tennessee State University. In 2007, the Gray Fossil Site & Museum opened its doors. It lets visitors see the amazing discoveries made there.
Millions of years ago, this area was a warm, wet forest with a pond inside a sinkhole. The fossils we find today are from the plants and animals that lived and died in and around that ancient pond.
This site is the first of its kind from the Appalachian mountains for this time period. It gives us a unique look into the past. Scientists have found many surprising things here. These include new types of red panda, rhinoceros, pond turtle, and even a new kind of hickory tree. The site also has the largest collection of fossil tapirs ever found!
Back then, the world was much warmer than it is now, especially in what is now Tennessee. This warm climate helped thick, humid forests grow.
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How the Gray Fossil Site Formed
The Gray Fossil Site is like a big time capsule. It's made of layers of clay and silt that settled at the bottom of an ancient lake. This lake formed inside a sinkhole. The fossil area is shaped like an oval, about 220 meters long and 180 meters wide. It goes deep, from about 7 meters to 39 meters down. The fossils found here are plentiful and often very well-preserved.
The ground here is made of old limestone rocks. Water flowing through these rocks creates caves and sinkholes. The sinkhole at Gray Fossil Site formed from several smaller collapses that joined together. Big rocks found in the lake sediments show that the sinkhole once had tall walls or overhangs. Chunks of rock would sometimes break off and fall into the lake.
By studying the mammal fossils, scientists believe the main fossil layers are between 4.5 and 4.9 million years old. This was during the Early Pliocene Epoch. There are hints of even older layers deeper down, from earlier sinkhole collapses.
The Site's Discovery and History
In May 2000, workers from the Tennessee Department of Transportation found the fossil site. They were building a new road near Gray, Tennessee. People in the local community quickly realized these fossils were special. They worked hard to save the site. In September 2000, the Governor of Tennessee, Don Sundquist, announced that the road project would move. This saved the fossil site for research and education.
The Gray Fossil Site then became a project of East Tennessee State University. The university hired experts in fossils and geology to manage the site. They also created a new Department of Geosciences. The university built a museum right at the site. This museum has research labs and exhibits for visitors. It first opened in August 2007. Today, it's simply known as the Gray Fossil Site & Museum.
What the Ancient Environment Was Like
The Gray Fossil Site was once a lake or pond surrounded by a forest. The ancient lake was home to many water animals. These included fish, pond turtles, salamanders, beavers, and alligators. Plant fossils, especially pollen, tell us about the forest. It had mostly oak, hickory, and pine trees, along with many smaller plants.
A study in 2020 looked at fossil mammal teeth to guess the ancient climate. It found that the average yearly temperature was about 16.8 °C (62.2 °F). This is similar to modern-day Atlanta, GA. The yearly rainfall was about 1,343mm (52.9in), like modern-day Tampa, FL. The coldest month's lowest temperature was around 2.6 °C (36.7 °F). These findings agree with earlier ideas that the site had a warmer and wetter climate than East Tennessee today. This is supported by finding warm-climate animals like alligators and plants like tupelo.
Many of the fossil animals and plants at Gray Fossil Site are related to species found in Europe and Asia today. Examples include red pandas and European badgers. This suggests that during the Early Pliocene, eastern North America was connected to Eurasia in terms of animal and plant life.
Amazing Fossils Found Here
The Gray Fossil Site is a Lagerstätte, which means it's a place with many well-preserved fossils. It's the only fossil site in the Appalachian region from this specific time period. This makes it a special window into the past.
Fish Fossils
All the fish fossils found so far at the Gray Fossil Site belong to the family called Centrarchidae.
Amphibian Fossils
- Salamanders: Several types have been found. These are the oldest known members of their families in the Appalachian mountains. This region is famous for its many kinds of salamanders today.
- Frogs: Many types of frogs have been identified, including Rana.
Reptile Fossils
- Alligators: Several well-preserved alligator fossils have been found. They seem to be a different kind of alligator than those we know today.
- Lizards: These include skinks, anguids, and helodermatids.
- Snakes: The most common snakes are colubrids. Several species have been found, including a unique fossil species called Zilantophis schuberti. Viperids (like vipers) are also present.
- Turtles: This is the most diverse group of reptiles here. It includes many types of box turtles, painted turtles, slider turtles, snapping turtles, and tortoises. Two species are only known from the Gray Site: the musk turtle Sternotherus palaeodorus and the slider turtle Trachemys haugrudi. T. haugrudi was named after Shawn Haugrud, who manages the site's lab and field work.
Bird Fossils
A study in 2011 found several types of birds at the Gray Fossil Site. The most common bird fossils were ducks.
Mammal Fossils
Odd-Toed Hoofed Mammals (Perissodactyls)
- Tapirus polkensis (dwarf tapir): The Gray Fossil Site has the largest group of tapir fossils ever found. It includes tapirs of all ages, from babies to very old adults.
- Teleoceras aepysoma (rhinoceros): Several rhino fossils have been found, including two almost complete skeletons. In 2019, these rhinos were identified as a new species. They were called the "high-bodied" Teleoceras because their front legs were longer than other species.
- Cormohipparion emslei (three-toed horse).
Even-Toed Hoofed Mammals (Artiodactyls)
- Peccaries: Two species have been found: Mylohyus elmorei and Prosthennops serus.
- Pediomeryx.
- Camel, possibly Megatylopus.
Carnivores
- Pristinailurus bristoli (red panda): This was named a new species in 2004. Two almost complete skeletons make it one of the best-known fossil pandas in the world.
- Arctomeles dimolodontus (Eurasian badger): This species was named at the same time as the Gray Fossil Site panda in 2004.
- Gulo sudorus (wolverine): This is the oldest known fossil wolverine. It was called the "sweaty wolverine" because the ancient climate at Gray was much warmer than where wolverines live today.
- Plionarctos (short-faced bear).
- Saber-toothed cat, possibly Machairodus.
- Buisnictis breviramus (skunk).
- Borophagus (bone crushing dog).
Elephants (Proboscidea)
- Mastodon: Scientists believe this is likely a new species. Several fossils have been found, including one almost complete and very large skeleton.
Rodents
- Several species, including beavers, packrats, and mice.
- Miopetaurista webbi (flying squirrel): A flying squirrel about the size of a cat. It is related to today's giant flying squirrels.
Rabbits and Hares (Lagomorphs)
- Alilepus vagus (rabbit).
- Notolagus lepusculus (rabbit).
Bats
- Two species of vespertilionid bats.
Shrews and Moles (Eulipotyphla)
- Several species of shrews and moles.
Sloths (Xenarthra)
- An unknown species of megalonychid sloth.
Invertebrate Fossils
Water-dwelling invertebrates found at the Gray Fossil Site include ostracods, snails, and small clams. We also have insect fossils, including at least four different families of beetles.
Plant Fossils
Plant fossils at the Gray Fossil Site include pollen, leaves, wood, fruits, seeds, and other parts. They show a wide variety of flowering plants, conifers, ferns, and other plants. The forest was mostly made up of different kinds of trees and shrubs. The most common were hickory, oak, and pine.
Several new, extinct plant species have been found at the Gray Fossil Site:
- Carya tennesseensis (hickory)
- Sinomenium macrocarpum (moonseed)
- Staphylea levisemia (bladdernut)
- Three species of Vitis (grapes)
- Corylopsis grisea (witch hazel)
- Passiflora sulcatasperma and Passiflora appalachiana (passion vines)
- Cavilignum pratchettii, which is the first extinct genus (a group of related species) of plant found at Gray.
Algae Fossils
Tiny algal fossils have been identified. They include many freshwater species. One new extinct species, Stigmozygodites grayensis, was named after the Gray Fossil Site in 2013.
Fungi Fossils
Several types of fungi have been found from tiny remains of fungal tissue.
More Places to Explore
- Ashfall Fossil Beds
- Pipe Creek Sinkhole
- La Brea Tar Pits
- Lagerstätte
- List of fossil sites
