The Gray Fossil Site is an Early Pliocene collection of fossils dating between 4.5 and 4.9 million years old, located near the town of Gray in Washington County, Tennessee. The site was discovered during road construction in May 2000. Shortly after which local officials decided to preserve the site for research and education. The site became part of East Tennessee State University, and the Gray Fossil Site & Museum was opened on the site in 2007.

Years ago the land around the Gray Fossil Site was a pond formed inside a sinkhole surrounded by a warm, wet forest. The fossils found in the area explain the ancient plants and animals that lived and died in and around the sinkhole pond.

As the first site of its age known from the Appalachian region, the Gray Fossil Site is a unique window into the past. Research at the site has brought many surprising discoveries. These included new species of red panda, rhinoceros, pond turtle, hickory tree, and more. The site also hosts the biggest known collection of fossil tapirs.

History
In late May of 2000, this fossil-rich area was discovered during a Tennessee Department of Transportation road construction project on the outside of Gray, TN. As it became clear that the fossils were not normal for this part of the country, members of the local community began an effort to preserve the site.

Many of the fossil fauna and flora of the Gray Fossil Site are closely related to modern-day species in Europe and Asia, including red pandas, European badgers, Chinese moonseed, and Corylopsis. This indicates that during the Early Pliocene, eastern North America maintained a biogeographic link with Eurasia.

Fossils
The Gray Fossil Site preserves a collection of preserved fossils. It is the only fossil site in the Appalachian region dating near the boundary between the Miocene and Pliocene Epochs. This offers a unique window into this region at this time.

Fish
All of the fish fossils found at the Gray Fossil Site belong to the family Centrarchidae.

Amphibians
 Salamanders. Several taxa have been identified, including Ambystoma, Desmognathus, Notophthalmus, and Plethodon. These are the oldest known members of their families in the Appalachian mountains, a region well-known for its modern salamander diversity.
Frogs. Numerous taxa, including Rana.

Reptiles
 Alligators. Multiple well-preserved specimens have been identified to the genus Alligator. These appear to be distinct from known alligator species.
 Lizards. Identified lizards include skinks, anguids, and helodermatids.
Snakes. The most common snakes are colubrids, of which multiple species have been identified. This includes the endemic fossil species Zilantophis schuberti. Viperids were also found.
 Turtles. These are the most diverse group of reptiles at the site, including several taxa of box turtles, painted turtles, slider turtles, snapping turtles, and tortoises. Among these are two species only known from the Gray Site, the musk turtle Sternotherus palaeodorus and the slider turtle Trachemys haugrudi.

Birds 
A preliminary study in 2011 identified several families of birds at the Gray Fossil Site, the most common of which were ducks.

Mammals 
Perissodactyls (odd-toed hoofed mammals)

Tapirus polkensis (dwarf tapir). The Gray Fossil Site has the largest tapir population of any known fossil site, including fossil tapirs of all ages, from very young juveniles to old adults.
Teleoceras aepysoma (rhinoceros). Several specimens are known, including two nearly complete skeletons. In 2019, the Gray Fossil Site rhinos were identified as a new species, named the "high-bodied" Teleoceras for their longer front legs compared to other species.
Cormohipparion emslei (three-toed horse)

Artiodactyls (even-toed hoofed mammals)

 Peccaries. Two species have been identified: Mylohyus elmorei and Prosthennops serus.
 Pediomeryx.
 Camel, possibly Megatylopus

Carnivora

 Pristinailurus bristoli (red panda). This was named as a new species in 2004. The two nearly complete skeletons make this one of the best-known fossil pandas.
 Arctomeles dimolodontus (Eurasian badger). This species was named alongside the Gray Fossil Site panda in 2004.
 Gulo sudorus (wolverine). The oldest known fossil wolverine. Named the "sweaty wolverine" since the ancient climate of Gray was much warmer than modern wolverine habitats.
 Plionarctos (short-faced bear).
 Saber-toothed cat, possibly Machairodus.
 Buisnictis breviramus (skunk)

Proboscidea (elephants)

 Mastodon. Likely a new species. This includes one nearly complete and very large skeleton. Early findings of proboscidean fossils at Gray were originally believed to belong to a gomphothere.

Rodents

 Several species, including beavers, packrats, and mice.

Lagomorphs

 Two species of extinct rabbits.

Bats

 Two species of vespertilionid bats.

Eulipotyphla
 Several species of shrews and moles.
Xenarthra

 An unknown species of megalonychid sloth.

Invertebrates 
Aquatic invertebrates of the Gray Fossil Site include ostracods, snails, and small clams. Insects are also known from fossilized exoskeletal remains and trace fossils, including at least four different families of beetles.

Plants 
Plant fossils at the Gray Fossil Site include pollen, leaves, wood, fruits, seeds, and other structures which represent a diverse flora of angiosperms, conifers, ferns, lycophytes, and bryophytes. The forest flora was dominated by a variety of trees and shrubs, of which the most common were hickory, oak, and pine.

Several previously unknown extinct plant species have been identified at the Gray Fossil Site:

 Carya tennesseensis (hickory)
 Sinomenium macrocarpum (moonseed)
 Staphylea levisemia (bladdernut)
 Three species of Vitis (grapes) 
 Corylopsis grisea (witch hazel)
 Cavilignum pratchettii, the first extinct genus of plant identified at the Gray Fossil Site.

Algae 
Algal microfossils have been identified as numerous freshwater species, including one previously unknown extinct species, Stigmozygodites grayensis, named from the Gray Fossil Site in 2013.

Fungi 
Several types of fungi have been found from microfossil remains of fungal tissue and fruiting bodies.

References

Tri-Cities, Tennessee
Museums in the United States