Fossil Butte National Monument is a

United States National Monument In the United States, a national monument is a protected area that can be created from any land owned or controlled by the federal government by proclamation of the president of the United States or an act of Congress. National monuments prot ...

managed by the

National Park Service The National Park Service (NPS) is an List of federal agencies in the United States, agency of the Federal government of the United States, United States federal government, within the US Department of the Interior. The service manages all List ...

, located west of

Kemmerer, Wyoming Kemmerer is the largest city in and the county seat of Lincoln County, Wyoming, United States. Its population was 2,415 at the 2020 census. History Explorer John C. Frémont discovered coal in the area during his second expedition in 1843. Th ...

, United States. It centers on an assemblage of

Eocene Epoch The Eocene ( ) is a geological epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''Ēṓs'', 'Dawn') and ...

(56 to 34 million years ago) animal and plant fossils associated with Fossil Lake—the smallest lake of the three great lakes which were then present in what are now

Wyoming Wyoming ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States, Western United States. It borders Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho t ...

Utah Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...

, and

Colorado Colorado is a U.S. state, state in the Western United States. It is one of the Mountain states, sharing the Four Corners region with Arizona, New Mexico, and Utah. It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas ...

. The other two lakes were Lake Gosiute and Lake Uinta. Fossil Butte National Monument was established as a national monument on October 23, 1972. Fossil Butte National Monument preserves the best paleontological record of

Cenozoic The Cenozoic Era ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterized by the dominance of mammals, insects, birds and angiosperms (flowering plants). It is the latest of three g ...

aquatic communities in North America and possibly the world, within the 50-million-year-old

Green River Formation The Green River Formation is an Eocene geologic formation that records the sedimentation in a group of intermountain lakes in three basins along the present-day Green River (Colorado River), Green River in Colorado, Wyoming, and Utah. The sedimen ...

— the ancient lake bed. Fossils preserved include fish, alligators, bats, turtles, a dog-sized horse, insects, and many other species of plants and animals — suggest that the region was a low, subtropical,

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...

basin when the sediments accumulated, over about a 2 million-year period.

Geologic formations

During the

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

this portion of

was a

sub-tropical The subtropical zones or subtropics are geographical and climate zones immediately to the north and south of the tropics. Geographically part of the temperate zones of both hemispheres, they cover the middle latitudes from to approximately 3 ...

lake ecosystem. The Green River Lake System contained three ancient lakes, Fossil Lake, Lake Gosiute, and Lake Uinta. These lakes covered parts of southwest

, northeast

and northwestern

. Fossil Butte is a remnant of the deposits from Fossil Lake. Fossil Lake was long from north to south and wide. Over the two million years that it existed, the lake varied in length and width. Fossil Buttes National Monument contains only 13 square miles () of the 900-square-mile () ancient lake. The ancient lake sediments that form the primary fossil digs is referred to as the

. In addition to this fossil-bearing strata, a large portion of the

Wasatch Formation The Wasatch Formation (Tw)Shroba & Scott, 2001, p.3 is an extensive highly fossiliferous Formation (geology), geologic formation stretching across several basins in Idaho, Montana, Wyoming, Utah and western Colorado. When the fossils were discovered, miners dug them up to sell to collectors. In particular, Lee Craig sold fossils from 1897 to 1937. Commercial fossil collecting is not allowed within the National Monument, but numerous quarries on private land nearby continue to produce extraordinary fossil specimens, both for museums and for private collectors.

Climate

Exhibits

The Fossil Butte National Monument Visitor Center features over 80 fossils and fossil casts on exhibit, including fish, a crocodile, turtle, bats, birds, insects and plants. A 13-minute video is shown about the fossils found at the site and what scientists have learned. Interactive exhibits let visitors create fossil rubbings to take home, and a computer program discusses fossils, geology and the current natural history of the monument.

Activities

During the summer, lab personnel prepare fossils in public. Summer activities also include ranger programs, hikes, paleontology and geology talks, and participation in fossil quarry collections for the park. Asterotrygon maloneyi Fossil Shack coll

A Junior Ranger program can be completed by children aged 5–12 (with exercises scaled to the child's age) in 3–4 hours. A highlight is hiking 3/4 mile up the butte to the dig, where interns from the

Geological Society of America The Geological Society of America (GSA) is a nonprofit organization dedicated to the advancement of the geosciences. History The society was founded in Ithaca, New York, in 1888 by Alexander Winchell, John J. Stevenson, Charles H. Hi ...

talk about their excavation and let children help them flake apart sedimentary deposits to discover fish fossils and

coprolite A coprolite (also known as a coprolith) is fossilized feces. Coprolites are classified as trace fossils as opposed to body fossils, as they give evidence for the animal's behaviour (in this case, diet) rather than morphology. The name ...

List of fossil species recovered at Fossil Butte National Monument

''Fish:'' *'' Asterotrygon'' spp, an extinct

stingray Stingrays are a group of sea Batoidea, rays, a type of cartilaginous fish. They are classified in the suborder Myliobatoidei of the order Myliobatiformes and consist of eight families: Hexatrygonidae (sixgill stingray), Plesiobatidae (deepwate ...

*''

Diplomystus dentatus ''Diplomystus'' is an extinct genus of freshwater and marine clupeomorph fish distantly related to modern-day extant herrings, anchovies, and sardines. It is known from the United States, China, and Lebanon from the Late Cretaceous to the middle ...

,'' an extinct

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...

*''

Knightia ''Knightia'' is an extinct genus of clupeid bony fish that lived in the freshwater lakes and rivers of North America and Asia during the Eocene epoch. The genus was erected by David Starr Jordan in 1907, in honor of the late University of Wyom ...

'' spp, an extinct fish related to

herring Herring are various species of forage fish, belonging to the Order (biology), order Clupeiformes. Herring often move in large Shoaling and schooling, schools around fishing banks and near the coast, found particularly in shallow, temperate wate ...

and

sardines Sardine and pilchard are common names for various species of small, oily forage fish in the herring suborder Clupeoidei. The term "sardine" was first used in English during the early 15th century; a somewhat dubious etymology says it come ...

*Seven extinct species of

perch Perch is a common name for freshwater fish from the genus ''Perca'', which belongs to the family Percidae of the large order Perciformes. The name comes from , meaning the type species of this genus, the European perch (''P. fluviatilis'') ...

*'' Heliobatis radians'', an extinct

*''

Notogoneus ''Notogoneus'' is an extinct genus of prehistoric ray-finned fish. A trace fossil attributed to ''Notogoneus osculus'' has been found in the Green River Formation. Species *†''Notogoneus cuvieri'' (Agassiz, 1844) *†''Notogoneus gracilis'' ...

'' spp, an extinct bottom-feeding fish *'' Crossopholis magnicaudatus''
Commons
, a 1-meter (40 inches) long predatory

paddlefish Paddlefish (family Polyodontidae) are a family of ray-finned fish belonging to order Acipenseriformes, and one of two living groups of the order alongside sturgeons (Acipenseridae). They are distinguished from other fish by their elongated rost ...

*'' Asineops squamifrons'', called 'mystery fish'- allocated its own family ''Asineopidae'' *Two extinct species of the family Osteoglossidae *'' Amphiplaga brachyptera,'' an extinct

freshwater fish Freshwater fish are fish species that spend some or all of their lives in bodies of fresh water such as rivers, lakes, ponds and inland wetlands, where the salinity is less than 1.05%. These environments differ from marine habitats in many wa ...

*Two extinct species of the genus '' Hiodon'' ''Amphibians:'' * '' Aleoamphiuma tetradactylum'', an extinct omnivorous salamander * '' Aerugoamnis paulus'', an extinct frog ''Mammals:'' *''

Coryphodon ''Coryphodon'' (from Greek , "point", and , "tooth", meaning ''peaked tooth'', referring to "the development of the angles of the ridges into points

n the molars N, or n, is the fourteenth letter of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages, and others worldwide. Its name in English is ''en'' (pronounced ), plural ''ens''. History ...

") is an extinct genus of pantodonts of the family Coryphodontidae. ''Coryphodo ...

'' *'' Onychonycteris finneyi'' and '' Icaronycteris index'', bats *''

Heptodon ''Heptodon'' is an extinct genus of tapir-type herbivore of the family Helaletidae endemic to North America during the Early Eocene. It lived from 50.3—48.6 mya, existing for approximately . ''Heptodon'' was about in length, and closely rese ...

'', an extinct

tapir Tapirs ( ) are large, herbivorous mammals belonging to the family Tapiridae. They are similar in shape to a Suidae, pig, with a short, prehensile nose trunk (proboscis). Tapirs inhabit jungle and forest regions of South America, South and Centr ...

*'' Apatemys chardini'', a tree-dwelling mammal similar to the

lemur Lemurs ( ; from Latin ) are Strepsirrhini, wet-nosed primates of the Superfamily (biology), superfamily Lemuroidea ( ), divided into 8 Family (biology), families and consisting of 15 genera and around 100 existing species. They are Endemism, ...

*'' Protorohippus'', an early horse-like mammal *'' Palaeosinopa didelphoides'', an otter-like carnivore *'' Hyopsodus wortmani'' 'tube sheep', a small omnivore *'' L. popoagicum'', an extinct

odd-toed ungulate Perissodactyla (, ), or odd-toed ungulates, is an order of ungulates. The order includes about 17 living species divided into three families: Equidae (horses, asses, and zebras), Rhinocerotidae (rhinoceroses), and Tapiridae (tapirs). They t ...

''Birds:'' *

Frigate bird Frigatebirds are a family of seabirds called Fregatidae which are found across all tropical and subtropical oceans. The five extant species are classified in a single genus, ''Fregata''. All have predominantly black plumage, long, deeply forked ...

s *''

Pseudocrypturus cercanaxius ''Pseudocrypturus'' is a genus of extinct paleognathous bird. Three species are known and the type species is ''Pseudocrypturus cercanaxius''. It is a relative of such modern birds as ostriches. It lived in the early Eocene. The holotype fossil ...

'', an extinct shoreline bird *'' Gallinuloides wyomingesis'', an extinct land fowl *'' Primobucco mcgrewi'', an extinct roller bird *Four extinct species of

parrot Parrots (Psittaciformes), also known as psittacines (), are birds with a strong curved beak, upright stance, and clawed feet. They are classified in four families that contain roughly 410 species in 101 genus (biology), genera, found mostly in ...

- '' Cyrillavis coldurnorum, Cyrillavis olsoni, Avolatavis tenens'' and ''

Tynskya eocaena ''Tynskya'' is an extinct genus of messelasturid bird. Distribution ''T. eocaena'', the type species, is known from fossils found in the North American Green River Formation. The Walton Member of the London Clay Formation of England contai ...

'' ''Reptiles:'' *''

Afairiguana ''Afairiguana avius'' is an extinct iguanid lizard known from a nearly complete and articulated skeleton discovered in rocks of the Early Eocene-aged Green River Formation of Wyoming, United States. As of the initial description, the skeleton rep ...

'', an extinct

anole Dactyloidae are a family of lizards commonly known as anoles (singular anole ) and native to warmer parts of the Americas, ranging from southeastern United States to Paraguay. Instead of treating it as a family, some authorities prefer to treat ...

*''

Boavus idelmani ''Boavus'' is an extinct genus of boa known primarily from Eocene-aged strata of North America. At least three species (''B. occidentalis, B. idelmani'', and possibly ''B. agilis'') are known from the Middle Eocene Green River lagerstätte in ...

'', a small extinct snake *''

Bahndwivici ''Bahndwivici'' is an extinct genus of lizard known from a nearly complete and articulated skeleton discovered in rocks of the Green River Formation of Wyoming, United States. The skeleton is very similar to that of the modern Chinese crocodile ...

, 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 Baenidae is an extinct family of paracryptodiran turtles known from the Early Cretaceous to Eocene of North America. While during the Early Cretaceous they are found across North America, during the Late Cretaceous they are only found in Laramidi ...

, turtle ''Plants:'' *

Palm tree The Arecaceae () is a family of perennial, flowering plants in the monocot order Arecales. Their growth form can be climbers, shrubs, tree-like and stemless plants, all commonly known as palms. Those having a tree-like form are colloquially c ...

s *

Cattails ''Typha'' is a genus of about 30 species of monocotyledonous flowering plants in the family Typhaceae. These plants have a variety of common names, in British English as bulrushStreeter D, Hart-Davies C, Hardcastle A, Cole F, Harper L. 2009. ...

*''

Gyrocarpus ''Gyrocarpus'' is a small genus of flowering plants in the Hernandiaceae family with a wide pantropical distribution. Species * '' Gyrocarpus americanus'' Jacq. (Pantropical A pantropical ("all tropics") distribution is one which covers tropi ...

'' spp *''Lagokarpos Lacustris,'' a type of distinct 'winged fruit' plant ''Lagokarpos'' found in lake deposits *''

Ailanthus confucii ''Ailanthus'' (; derived from ''ailanto,'' an Ambonese word probably meaning "tree of the gods" or "tree of heaven") is a genus of trees belonging to the family Simaroubaceae, in the order Sapindales (formerly Rutales or Geraniales). The genus ...

'' *''

Platycerium ''Platycerium'' is a genus of about 18 fern species in the polypod family, Polypodiaceae. Ferns in this genus are widely known as staghorn or elkhorn ferns due to their uniquely shaped fronds. This genus is Epiphyte, epiphytic and is native to tr ...

'', a staghorn

fern The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissue ...

*'' Salvinia preauriculata'', a water fern *'' Lygodium kaulfussi'' 'climbing fern' *''

Nelumbo ''Nelumbo'' is a genus of aquatic plants with large, showy flowers. Members are commonly called lotus, though the name is also applied to various other plants and plant groups, including the unrelated genus '' Lotus''. Members outwardly resemb ...

'' spp *'' Chaneya tenuis''; a genus of uncertain affinities * Birthwort (species unknown) *

Soapberry Soapberry is a common name for several flowering plants both native to the Americas and may refer to: * ''Sapindus ''Sapindus'' is a genus of about thirteen species of shrubs and small trees in the lychee family, Sapindaceae and tribe Sapindea ...

*Species similar to a

walnut A walnut is the edible seed of any tree of the genus '' Juglans'' (family Juglandaceae), particularly the Persian or English walnut, '' Juglans regia''. They are accessory fruit because the outer covering of the fruit is technically an i ...

''Arthropods:'' * '' Bechleja rostrata'', an extinct species of

shrimp A shrimp (: shrimp (American English, US) or shrimps (British English, UK)) is a crustacean with an elongated body and a primarily Aquatic locomotion, swimming mode of locomotion – typically Decapods belonging to the Caridea or Dendrobranchi ...

* ''

Procambarus primaevus ''Procambarus'' is a genus of crayfish in the family Cambaridae, all native to North and Central America. It includes a number of troglobitic species, and the marbled crayfish (''marmorkrebs''), which is parthenogenetic. Originally described a ...

'', an extinct species of

crayfish Crayfish are freshwater crustaceans belonging to the infraorder Astacidea, which also contains lobsters. Taxonomically, they are members of the superfamilies Astacoidea and Parastacoidea. They breathe through feather-like gills. Some spe ...

* Three unidentified species of

spider Spiders (order (biology), order Araneae) are air-breathing arthropods that have eight limbs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude spider silk, silk. They are the largest order of arachnids and ran ...

Dragonflies A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata. About 3,000 extant species of dragonflies are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat threate ...

Damselflies Damselflies are flying insects of the suborder Zygoptera in the order Odonata. They are similar to dragonflies (which constitute the other odonatan suborder, Epiprocta) but are usually smaller and have slimmer bodies. Most species fold the win ...

Crickets Crickets are orthopteran insects which are related to bush crickets and more distantly, to grasshoppers. In older literature, such as Imms,Imms AD, rev. Richards OW & Davies RG (1970) ''A General Textbook of Entomology'' 9th Ed. Methuen 886 ...

* Other insects including

bee Bees are winged insects closely related to wasps and ants, known for their roles in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyletic lineage within the superfamil ...

s and

ant Ants are Eusociality, eusocial insects of the Family (biology), family Formicidae and, along with the related wasps and bees, belong to the Taxonomy (biology), order Hymenoptera. Ants evolved from Vespoidea, vespoid wasp ancestors in the Cre ...

s Primary source:Green River Formation Fossils
at Fossil Butte

Gallery

File:Knightia eocaena FBNM.JPG, '' Knightia eocaena'' fish, about long. ''Knightia'' is the most commonly excavated fossil fish in the world. File:Cockerellites liops Green River Formation.jpg, '' Cockerellites liops'' from Fossil Lake. An extinct

. About long. File:Fossil Sabalites sp palm.jpg, Fossil ''Sabalites'' sp. palmetto frond, about long. File:Notogoneus osculus.png, '' Notogoneus osculus,'' a bottom-dwelling fish from Fossil Lake. File:Fossil bird Field Museum.jpg, An unidentified fossil bird from FBNM, in the collections of the

Field Museum The Field Museum of Natural History (FMNH), also known as The Field Museum, is a natural history museum in Chicago, Illinois, and is one of the largest such museums in the world. The museum is popular for the size and quality of its educationa ...

File:Buprestidae beetle, FBNM.jpg, A well-preserved

Buprestidae Buprestidae is a family (biology), family of beetles known as jewel beetles or metallic wood-boring beetles because of their glossy Iridescence, iridescent colors. Larvae of this family are known as flatheaded borers. The family is among the lar ...

beetle ( long) from the FBNM collections. Other beetles, flies and ''

Hemiptera Hemiptera (; ) is an order of insects, commonly called true bugs, comprising more than 80,000 species within groups such as the cicadas, aphids, planthoppers, leafhoppers, assassin bugs, bed bugs, and shield bugs. They range in size from ...

'' bugs have also been found in the Fossil Lake sediments. File:Heliobatis radians Green River Formation.jpg, '' Heliobatis radians'', an extinct

, had small teeth for crushing snails and other mollusks and barbed spines on the tail for defense. This specimen is about long, including the tail.

References

External links

National Park Service: official Fossil Butte National Monument website

from FBNM * ttps://web.archive.org/web/20080906194457/http://3dparks.wr.usgs.gov/2006/fossilbutte/html2/fossil06.htm Photo tour of FBNM from

USGS The United States Geological Survey (USGS), founded as the Geological Survey, is an government agency, agency of the United States Department of the Interior, U.S. Department of the Interior whose work spans the disciplines of biology, geograp ...

Paleontology of Green River fossils
from

University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California), is a Public university, public Land-grant university, land-grant research university in Berkeley, California, United States. Founded in 1868 and named after t ...

Geologic travel guide
from

American Geological Institute The American Geosciences Institute (AGI) is a nonprofit federation of about 50 geoscientific and professional organizations that represents geologists, geophysicists, and other earth scientists. The organization was founded in 1948. The name of ...

{{Authority control National Park Service national monuments in Wyoming Eocene Fossil parks in the United States Protected areas of Lincoln County, Wyoming Natural history museums in Wyoming Museums in Lincoln County, Wyoming Protected areas established in 1972 Paleontology in Wyoming Paleontological protected areas in the United States 1972 establishments in Wyoming 1972 in paleontology