Fossil Butte National Monument facts for kids

Quick facts for kids Fossil Butte National Monument
IUCN Category V (Protected Landscape/Seascape)
Fossil Butte National Monument
Fossil Butte National Monument Location in Wyoming Show map of Wyoming Fossil Butte National Monument Location in the United States Show map of the United States
Location	Lincoln County, Wyoming, USA
Nearest city	Kemmerer, WY
Area	8,198 acres (33.18 km2)
Established	October 23, 1972 (1972-October-23)
Visitors	16,552 (in 2011)
Governing body	National Park Service
Website	Fossil Butte National Monument

Heliobatis radians, an extinct stingray, had small teeth for crushing snails and other mollusks and barbed spines on the tail for defense. This specimen is about 35 centimetres (14 in) long, including the tail.

This 1.7-meter (5 foot 6 inch) Axestemys byssinus is one of the largest turtles known from Fossil Lake.

Fossil Butte National Monument is a special place in Wyoming, USA. It is managed by the National Park Service. This monument is famous for its amazing collection of plant and animal fossils.

These fossils are from the Eocene Epoch, a time between 56 and 34 million years ago. They come from an ancient body of water called Fossil Lake. This lake was the smallest of three huge lakes that once covered parts of what is now Wyoming, Utah, and Colorado. The other two lakes were Lake Gosiute and Lake Uinta.

Fossil Butte National Monument was created on October 23, 1972. It protects some of the best fossil records of water-dwelling creatures from the Cenozoic Era. These fossils are found in the 50-million-year-old Green River Formation. This formation is what's left of the ancient lake bed.

Scientists have found fossils of fish, alligators, bats, turtles, and even a horse the size of a dog! There are also many types of insects and plants. These fossils tell us that the area was a warm, wet, freshwater basin for about 2 million years.

Ancient Lakes and Fossils

Map of major Wyoming geological formations, showing Fossil Butte (lower left) far south of Yellowstone (upper left), southwest across the state from Devils Tower (upper right).

Millions of years ago, during the Eocene time, this part of Wyoming was a warm, wet place. It was home to a huge lake system called the Green River Lake System. This system included three ancient lakes: Fossil Lake, Lake Gosiute, and Lake Uinta. These lakes spread across parts of Wyoming, Utah, and Colorado.

Fossil Butte is a small part of what was once Fossil Lake. This ancient lake was about 40 to 50 miles (64 to 80 km) long and 20 miles (32 km) wide. Its size changed over the 2 million years it existed.

Fossil Butte National Monument covers about 13 square miles (8,198 acres (33,180,000 m²)). This is just a tiny piece of the original 900-square-mile (595,200 acres (2.409×10⁹ m²)) ancient lake. The main fossil-rich layers are called the Green River Formation.

The monument also has parts of the Wasatch Formation. This formation contains sediments from ancient rivers and streams. It shows what the land around the lake was like. Here, scientists have found fossil teeth and bone pieces from early Eocene mammals. These include very old types of primates and horses.

Exploring the Monument

Visitor Center Exhibits

The Fossil Butte National Monument Visitor Center is a great place to start your visit. It has over 80 fossils and fossil copies on display. You can see fish, a crocodile, turtles, bats, birds, insects, and plants.

There's a 13-minute video that explains the fossils found here. It also shares what scientists have learned from them. You can also try interactive exhibits. These let you make fossil rubbings to take home. A computer program teaches you about fossils, geology, and the monument's natural history.

Summer Activities

If you visit in the summer, you might see lab workers preparing fossils. They do this in public, so you can watch them carefully clean and preserve these ancient treasures.

Summer is also a fun time for other activities. Park rangers lead programs and hikes. You can learn about paleontology (the study of fossils) and geology (the study of Earth's rocks). Sometimes, visitors can even help with fossil collecting for the park.

Stingray prepared by R. Lee Craig (Asterotrygon maloneyi). This fossil was prepared around 1920.

Junior Ranger Program

Kids aged 5–12 can join the Junior Ranger program. It takes about 3–4 hours to complete. A highlight is hiking about 3/4 mile up the butte to the dig site. Here, interns from the Geological Society of America work. They talk about their fossil digs. They might even let you help flake apart sedimentary rocks to find fish fossils or coprolites (fossilized animal droppings!).

Fossil Species Found Here

Fossil Butte National Monument is a treasure chest of ancient life. Here are some of the amazing fossil species that have been found:

Fish Species

• Asterotrygon spp, an extinct stingray
• Diplomystus dentatus, an extinct ray-finned fish
• Knightia spp, an extinct fish related to herring and sardines
• Seven extinct species of perch
• Heliobatis radians, an extinct stingray
• Notogoneus spp, an extinct bottom-feeding fish
• Crossopholis magnicaudatus (Commons), a 1-meter (40 inches) long predatory paddlefish
• Asineops squamifrons, called 'mystery fish'
• Two extinct species of the family Osteoglossidae
• Amphiplaga brachyptera, an extinct freshwater fish
• Two extinct species of the genus Hiodon

Amphibians

• Aleoamphiuma tetradactylum, an extinct omnivorous salamander
• Aerugoamnis paulus, an extinct frog

Mammals

• Coryphodon
• Onychonycteris finneyi and Icaronycteris index, ancient bats
• Heptodon, an extinct animal similar to a tapir
• Apatemys chardini, a tree-dwelling mammal like a lemur
• Protorohippus, an early horse-like mammal
• Palaeosinopa didelphoides, an otter-like meat-eater
• Hyopsodus wortmani 'tube sheep', a small omnivore
• L. popoagicum, an extinct odd-toed ungulate

Birds

• Frigate birds
• Pseudocrypturus cercanaxius, an extinct shoreline bird
• Gallinuloides wyomingesis, an extinct land fowl
• Primobucco mcgrewi, an extinct roller bird
• Four extinct species of parrots: Cyrillavis coldurnorum, Cyrillavis olsoni, Avolatavis tenens and Tynskya eocaena

Reptiles

• Afairiguana, an extinct anole
• Boavus idelmani, a small extinct snake
• Bahndwivici, Afairiguana avius and Bahndwivici ammoskius, extinct lizards
• Baptemys wyomingenis, an extinct river turtle
• Echmatemys wyomingensis, an extinct pond turtle
• Borealosuchus wilsoni and Tsoabichi greenriverenis, extinct crocodiles
• Three species of soft-shell turtles: Apalone heteroglypta, Axestemys byssinus and Hummelichelys guttata
• Baenidae, a type of turtle

Plants

• Palm trees
• Cattails
• Gyrocarpus spp
• Lagokarpos Lacustris, a type of distinct 'winged fruit' plant found in lake deposits
• Ailanthus confucii
• Platycerium, a staghorn fern
• Salvinia preauriculata, a water fern
• Lygodium kaulfussi 'climbing fern'
• Nelumbo spp
• 

  †Chaneya tenuis
  Chaneya tenuis; a genus of uncertain affinities
• Birthwort (species unknown)
• Soapberry
• Species similar to a walnut

Arthropods

• Bechleja rostrata, an extinct species of shrimp
• Procambarus primaevus, an extinct species of crayfish
• Three unidentified species of spider
• Dragonflies
• Damselflies
• Crickets
• Other insects including bees and ants

Primary source:

Images for kids

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  Knightia eocaena fish, about 10 centimetres (3.9 in) long. Knightia is the most commonly excavated fossil fish in the world.

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  Cockerellites liops from Fossil Lake. An extinct perch. About 11.5 centimetres (4.5 in) long.

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  Fossil Sabalites sp. palmetto frond, about two metres (6.6 ft) long.

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  Notogoneus osculus, a 53-centimetre-long (21 in) bottom-dwelling fish from Fossil Lake.

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  An unidentified fossil bird from FBNM, in the collections of the Field Museum

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  A well-preserved Buprestidae beetle (3.5 cm or 1.4 in long) from the FBNM collections. Other beetles, flies and Hemiptera bugs have also been found in the Fossil Lake sediments.