A View South from Cundick Ridge
A view south from Cundick Ridge located approximately 2 miles as the crow flies north of the visitor center. A one mile walk on a dirt road (vehicles prohibited) gets you here.
Fresh-Water Ray - National Parks Gallery
"Heliobatis radians" is a prehistoric stingray which lived in fresh water lakes during the Eocene. Fossils of "Heliobatis" have been found in rocks within and around Fossil Butte National Monument, Wyoming.
Fossil Butte national monument - Undescribed Millipede
The only millipede fossil found to date in Fossil Lake.
Snow Covered Butte - National Parks Gallery
Winter storms often lay a blanket of snow over the landscape. One storm can dump several feet of snow.
Fresh-Water Fish - National Parks Gallery
"Diplomystus dentatsus" is a prehistoric herring like fish. It lived in fresh water lakes during the Eocene Fossils of Diplomystus have been found in rocks within and around Fossil Butte National Monument, Wyoming.
North Slope of Cundick Ridge - Public Domain image, National Parks Gal...
North facing slopes at higher elevation support aspen and and limber pine forests. The aspen leaves are beginning to show their fall colors.
Arches National Park, Ipomopsis aggregata
Common name: scarlet gilia. Family: Polemoniaceae (Phlox Family). Confirmed as present in the following Northern Colorado Plateau Network parks: Arches National Park, Bryce Canyon National Park, Canyonlands Nat... More
Fossil Butte national monument - Dipteronia sp.
This seed is from a plant in the Sapindaceae family. The seed is approximately 1.4 cm across. Catalog number FOBU9987.
Fossil Butte national monument - Fossilized fish
Fossilized fish in Fossil Butte National Monument, Wyoming.
Looking for fossils - National Parks Gallery
GIP Anthony Menicucci (center) opening the scientific fossil quarry and looking for fossils at Fossil Butte National Monument, Wyoming.
Fossil Butte national monument - Examining limestone
Anthony Menicucci, Paleontology GIP, lifting a slab of limestone in the research quarry at Fossil Butte National Monument, Wyoming.
Fossil Butte national monument - Examining limestone
Paleontology GIP Anthony Menicucci examining fragments of limestone from the Green River Formation for fossils exposed on the surface in Fossil Butte National Monument, Wyoming.
Asterotrygon maloneyi, male - National Parks Gallery
The narrow, paired fins at the base of the tail were used to position the female stingray to most effectively fertilize eggs as they were laid. Catalog number FOBU408
Fossil Butte national monument - Junior Ranger
Nicole Reynaud, Paleontology GIP for Fossil Butte National Monument, Wyoming, showing a Junior Ranger fossils in the field.
National parks: Leaf - public domain image
Unidentified leaf from the Fossil Lake deposits in Fossil Butte National Monument, Wyoming.
Fossil Butte national monument - Cardiospermum coloradoensis
This small lobed leaf of a balloon vine occurs in great abundance in the Parachute Creek Member of the Green River Formation deposited by Lake Uinta in what is now Colorado and Utah. Catalog number FOBU10725.
National parks: Leaf - public domain image
Unidentified leaf from the Fossil Lake deposits in Fossil Butte National Monument, Wyoming.
Fossil Butte national monument - Crossopholis magnicaudatus
The predatory fish, Crossopholis magnicaudatus, from the Green River Formation at Fossil Butte National Monument, Wyoming.
Unidentified extinct baenid turtle
Unidentified extinct baenid turtle from the Green River Formation in Fossil Butte National Monument, Wyoming.
Fossil Butte national monument - Gyrocarpus sp.
This came from a tree related to living sassafras trees. Both trees produce leaves in three shapes, unlobed, two lobed like this one, and three lobed. The leaf is 41.9 cm. Catalog number FOBU10668.
inidentified leaf, approximately 5 cm long
Fossilized plants are often difficult to identify because their parts, stem, roots, leaves, and fruiting structures are often not attached.
Fossil Butte national monument - unidentified flower
The detailed preservation of this flower is due, in part, to the fine-grained nature of the limestone matrix it is found in.
unidentified member of the Trionychidae family
This 1.7 meter (5 foot 6 inch) softshell turtle is one of the largest turtles from Fossil Lake. During the Eocene, trionychid turtles reached maximum size. Today, North America's largest softshell turtles reach... More
unidentified insect of the order Hemiptera
Collectively known as true bugs, Hemiptera species include cicadas, aphids, planthoppers, leafhoppers, shield bugs and others. (fossil is approximately 1 cm long)
beetle of the family Buprestidae, 3.5 cm long
Because of their glossy irridescent colors, members of the family Buprestidae are known as jewel beetles or metallic wood-boring beetles, such as the emerald ash borer.
unidentified insect, approximately 1 cm long
Preserved insects from Fossil Lake sometimes show color patterns, wing venation, and sex related characteristics. Note the pattern on the wings of this fossil insect.
Knightia eocaena, approximately 11 cm long
Knightia eocaena is perhaps the most common complete vetebrate fossil in the world. It is Wyoming's state fossil.
Fossil Butte national monument - unidentified flower
Fossilized plants are more difficult to identify than living plants because their parts often become separated before they are preserved. The plant that produced this flower may be impossible to identify becaus... More
unidentified beetle, approximately 4.5 cm long
Beetles are the most diverse and abundant group of animals today but are poorly represented as fossils in Fossil Lake.
unidentified leaf, approximately 15 cm long
Two hundred and seventy six leaves, seeds and flowers are known from the Fossil Lake deposits. Fossil plants are key in determining the climate of past environments.
unidentified leaf, approximately 8 cm long
Over 300 fossil plants have been discovered in the Fossil Lake deposits.
unidentified fly, approximately 1 cm long
The insect fossils from Fossil Lake sometimes show color patterns, wing venation, and sex-related characteristics. Notice the venation pattern on the wings of this fly.
Cockerellites liops, approximately 13 cm long
Cockerellites liops (formerly Priscacara liops) occurs in at least one mass mortality layer indicating it was a schooling fish.
unidentified insect of the order Hemiptera, 1.5 cm
Preserved insects from Fossil Lake sometimes show color patterns, wing venation, and sex related characteristics. Note the pattern around the edge of this true bug's abdomen.
unidentified leaf, approximately 3 cm long
Plants are key to understanding past climates. If a population of 25 or more different shaped leaves are collected from a locality, paleontologists use a technique called leaf-margin analysis to estimate temper... More
unidentified baenid turtle - National Parks Gallery
This ten-inch-long turtle belongs to the Baenidae family, an extinct North American group. Shell characteristics, a very long tail and recurved claws suggest they were strong bottom walking turtles.
Mass mortality of Knightia eocaena
Knightia eocaena was a schooling fish. This specimen is from the sandwich beds where several mortality beds of adult fish are found. (fish are approximately 10 cm long)
Palmites sp., approximately 2 meters long
The presence of palm fossils indicate a much warmer and wetter climate 52 million years ago, similar to the Gulf coast states today.
Diplomystus dentatus with Knightia in its mouth
This fossil fish was not found in a mass mortality (beds that contain hundreds of fish on one surface) suggesting it did not die in a catastrophe. It most likely died from starvation or suffocation because it c... More
Knightia alta, approximately 12.5 cm long
In Fossil Lake, the deep-bodied Knightia alta is less common that Knightia eocaena.
Mioplosus labracoides, approximately 9 cm long
The mouth of Mioplosus, an extinct perch-like fish, was lined with numerous tiny sharp teeth. This aided in grasping prey, but also prevented them from expelling fish too big to injest.
Phareodus encaustus, 50 cm long
Large teeth and rear-placed fins make Phareodus encaustus well suited for catching and eating other fish.
Crossopholis magnicaudatus, approximately 1 m long
Unlike its filter-feeding modern North American relative, Crossopholis was a predatory fish.
Fossil Butte national monument - Protorohippus sp.
Most mammal fossils consist of teeth and bone fragments. This fully-articulated early horse is an extremely rare find and to date, the first of two horses found in the Green River Formation.
Heliobatus radians, approximately 30 cm long
Heliobatus radians had small teeth for crushing snails and other mollusks and barbed spines on the tail for defense.
Procambarus primaevus, approximately 5 cm long
Crayfish lived in the shallow, near-shore water of Fossil Lake. Procambarus is known only from the Eocene deposits of Fossil Lake. Its closest living relative, Austrocambarus, is found in Mexico.
Onychonycteris finneyi (cast) - National Parks Gallery
The fossils of the Green River Formation's ancient Fossil Lake are remarkable for the broad spectrum of species found here. This 5.5 inch long bat is the most primitive bat known. Claws on each finger of its wi... More
Fossil Butte national monument - GeoCorps interns
GeoCorps intern, Taormina Lepore, is helping a young visitor split open a rock at the Fossil Butte National Monument, Wyoming, research quarry.
Fossil Butte national monument - Cleaning fossils
GIP Julie Rozen cleaning fossils with a Junior Ranger at Fossil Butte National Monument, Wyoming.
Tourist Attraction - Fossils on the Ridge
Freeze/thaw action fractures rock revealing the fossils. Picryl description: Public domain photograph of National Park, nature, free to use, no copyright restrictions image.
Visitor Center in Snow-Covered Landscape
Up to two feet of snow is on the ground November - March.
Cleaning a fossil - National Parks Gallery
Here Megan Ferre (Paleontology GIP) is cleaning an exploded fish fossil at the visitor’s center during a demonstration for visitors at Fossil Butte National Monument, Wyoming.
Looking for fossils - National Parks Gallery
Megan Ferre (Paleontology GIP) searches for fossils at the Fossil Butte National Monument, Wyoming, research quarry.
Fossil Butte national monument - Paleontology GIP
Paleontology GIP, Megan Ferre, pointing out a fossilized fish tail in the visitor’s center at Fossil Butte National Monument, Wyoming.
Megan Ferre, GIP intern - Public Domain image, National Parks Gallery
Megan Ferre, GIP intern cleans an exploded fish fossil at Fossil Butte National Monument, Wyoming.
Double Rainbow On Fossil Butte - Public Domain image, National Parks G...
Thunderstorms bring rain and colorful rainbows. Picryl description: Public domain photograph of National Park, nature, free to use, no copyright restrictions image.
A View of Fossil Basin from Cundick Ridge
Ancient Fossil Lake deposits are visible in the distance. Picryl description: Public domain photograph of National Park, nature, free to use, no copyright restrictions image.
Fossil Butte national monument - Fossil Butte
Fossil Butte is capped by limestone deposited by ancient Fossil Lake, part of the famous Green River Formation. Sagebrush steppe vegetation dominates the landscape of Fossil Butte National Monument.
Fossil Butte national monument - Exploded gar
A fossilized exploded gar (fish) being prepared in the lab by GIP Taryn O'Connell (Fossil Butte National Monument, Wyoming).
Exhibit at Fossil Butte National Monument
Exhibit at Fossil Butte National Monument, Wyoming, about fossilization that Guest Scientist Taryn O'Connell assisted with.
Amanda Meacham, GIP intern - Public Domain image, National Parks Galle...
Amanda Meacham, GIP intern preparing fossil fish at Fossil Butte National Monument, Wyoming.
Mitchell Hermann, GIP intern - Public domain natural history illustrat...
Mitchell Hermann, GIP intern excavating fossils at Fossil Butte National Monument, Wyoming.
Green River Formation fossil, Fossil Butte National Monument, 2016.
Crayfish lived in the shallow, near-shore water of Fossil Lake and are known only from Eocene lake deposits. The closest living relative of Procambarus is Austrocambarus, found in Mexico. This Procambarus prima... More
Green River Formation fossil, Fossil Butte National Monument, 2016.
The presence of palm fossils indicate a much warmer and wetter climate, similar to today's gulf coast region, occurred 52-million yeasr ago. Palmitates sp. Specimen approximately 2-meters long.
Mass Mortality of Cockerellites liops
For number, variety, and detail of fossil fish, few places equal ancient Fossil Lake of the Green River Formation. Mass mortalities such as this one are uncommon. These multiple deaths may have been caused by t... More
Green River Formation fossil, Fossil Butte National Monument, 2016.
Cockerellites liops (formerly Priscacara liops) occurs in at least one mass mortality layer, indicating that it was a schooling fish. Specimen approximately 13-cm long.
Fossil Butte national monument - Cockerellites liops
Ancient Fossil Lake of the Green River Formation is known for excellent preservation, abundance and diversity of life. This mass mortality of fossil fish is just one example.
Green River Formation fossil, Fossil Butte National Monument, 2016.
In Fossil Lake, this deep-bodied Knightia alta is less common than Knightia eocaena. Knightia alta specimen approximately 12.5-cm long.
Green River Formation fossil, Fossil Butte National Monument, 2016.
Fossilized plants are much more difficult to identify than living plants because their delicate parts often become separated before they are preserved. The plant that produced this flower may be impossible to i... More
Green River Formation fossil, Fossil Butte National Monument, 2016.
Large teeth and rear-placed fins make Phareodus encaustus well-suited for catching and eating other fish. Specimen approximately 50-cm long.
Green River Formation fossil, Fossil Butte National Monument, 2016.
Fossilized plants are much more difficult to identify than living plants because their delicate parts often become separated before they are preserved. The detailed preservation of this unidentified flower is d... More
Green River Formation fossil replica, Fossil Butte National Monument, ...
A broad range of species can be found in the Green River Formation's ancient fossil lake. This 5.5-inch long bat is the most primitive bad known to science. Claws on each finger of its wings indicate that it wa... More
Green River Formation fossil, Fossil Butte National Monument, 2016.
The mouth of Mioplosus was lined with numerous tiny sharp teeth useful for grasping prey but, as evidenced from this specimen, also prevented unfortunate Mioplosus from expelling fish that were too large for it... More
Fossil Butte national monument - Ancestral Bat
"Icaronycterix index" is a very early bat that lived during the Eocene. Fossils of "Icaronycterix" have been found near Fossil Butte National Monument, Wyoming.