Prehistoric Trackways National Monument is a national monument in the

Robledo Mountains The Robledo Mountains are a mountain range in Doña Ana County, New Mexico just northwest of Las Cruces. They are an uplifted block of Paleozoic rocks on the west side of the Rio Grande Rift. The range was named for Pedro Robledo, who died on Ma ...

of Doña Ana County,

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe , LargestCity = Albuquerque , LargestMetro = Tiguex , OfficialLang = None , Languages = English, Spanish ( New Mexican), Navajo, Ke ...

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

, near the city of Las Cruces. The monument's

Paleozoic Era The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ''z ...

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

s are on of land administered by the Bureau of Land Management. It became the 100th active U.S. national monument when it was designated on March 30, 2009.

Fossils

The Prehistoric Trackways National Monument site includes a major deposit of Paleozoic Era

ized footprints in fossil mega-trackways of land animals, sea creatures, and insects. These are known as

trace fossil A trace fossil, also known as an ichnofossil (; from el, ἴχνος ''ikhnos'' "trace, track"), is a fossil record of biological activity but not the preserved remains of the plant or animal itself. Trace fossils contrast with body fossils, ...

s or ichnofossils. There are also fossilized plants and

petrified wood Petrified wood, also known as petrified tree (from Ancient Greek meaning 'rock' or 'stone'; literally 'wood turned into stone'), is the name given to a special type of '' fossilized wood'', the fossilized remains of terrestrial vegetation. ' ...

present, as well as plenty of marine invertebrate fossils including

brachiopods Brachiopods (), phylum Brachiopoda, are a phylum of trochozoan animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear end, wh ...

gastropods The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. The ...

, cephalopods, bivalves, and echinoderms. Much of the fossilized material originated during the

Permian Period The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleoz ...

and is around 280 million years old. Dimetrodon track

Some of the animals who may have left tracks in the Robledo Mountains include '' Dimetrodon'', ''

Eryops ''Eryops'' (; from Greek , , 'drawn-out' + , , 'face', because most of its skull was in front of its eyes) is a genus of extinct, amphibious temnospondyls. It contains the single species , the fossils of which are found mainly in early Permian (a ...

'', ''

Edaphosaurus ''Edaphosaurus'' (, meaning "pavement lizard" for dense clusters of teeth) is a genus of extinct edaphosaurid synapsids that lived in what is now North America and Europe around 303.4 to 272.5 million years ago, during the Late Carboniferous to ...

'', and multiple other

pelycosaurs Pelycosaur ( ) is an older term for basal or primitive Late Paleozoic synapsids, excluding the therapsids and their descendants. Previously, the term ''mammal-like reptile'' had been used, and pelycosaur was considered an order, but this is now ...

. There are at least 13 major trace fossils found at the monument, including ''

Selenichnites ''Selenichnites'' (‘moon track’) is a Cambrian to Jurassic trace fossil that has been found on every continent. It consists of crescent-shaped impressions interpreted as resting or burrowing traces of Xiphosura (extinct relatives of horsesho ...

'' (sel-EEN-ick-NIGHT eez) or moon-shaped trace, ''

Kouphichnium ''Kouphichnium'' is an ichnogenus that has been attributed to limulids (horseshoe crabs). ''Kouphichnium'' fossils resemble the footprints of birds, sometimes in conjunction with a medial line, and were initially thought to be bird or pterosaur ...

'' (koof-ICK-nee-um) or light trace, ''

Palmichnium ''Palmichnium'' ("palm trace") is an ichnofossil genus, interpreted as a eurypterid trackway. It has been found by many places around the world, such as Australia, Canada, United States or Wales. Its trackways consist of three or four subcircular ...

'' (pal-ICK-nee-um) or palm rondtrace, ''

Octopodichnus ''Octopodichnus'' (‘eight-footed trace’) is a Permian to Jurassic trace fossil A trace fossil, also known as an ichnofossil (; from el, ἴχνος ''ikhnos'' "trace, track"), is a fossil record of biological activity but not the pres ...

'' (oct-toe-pod-ICK-nuss) or eight-footed trace, ''

Lithographus ''Lithographus'' (‘rock writing’) is a Carboniferous to Cretaceous trace fossil A trace fossil, also known as an ichnofossil (; from el, ἴχνος ''ikhnos'' "trace, track"), is a fossil record of biological activity but not the pr ...

'' (lith-oh-GRAFF-us) or rock writing, ''

Tonganoxichnus ''Tonganoxichnus'' (‘Tonganoxie, Kansas trace’) is a Pennsylvanian to Permian trace fossil that has been found in North America. The ichnogenus originally included two ichnospecies found in close association. ''T. buildexensis'' is interpre ...

'' (tong-a-nox-ICK-nuss) or Tonganoxie ansastrace, ''

Augerinoichnus ''Augerinoichnus'' (‘Augerino trace’) is a Permian trace fossil that has been found in New Mexico, US. The trace fossil is a corkscrew-shaped burrow that, when partially eroded out at the surface, has the appearance of a set of horseshoe-sh ...

'' (aw-gurr-EE-no-ICK-nuss) or

Augerino The augerino is a legendary creature present in the folk tales of lumberjack and ranching communities in the western United States.Carol Rose, ''Giants, Monsters, and Dragons: An Encyclopedia of Folklore, Legend and Myth''. Norton, 2001, pp. 30- ...

trace, '' Undichna'' (und-ICK-nuh) or wave-shaped trace, '' Serpentichnus'' (serpent-ICK-nuss) or snake-like trace, '' Batrachichnus'' (baa-track ICK-nuss) or frog trace, '' Dromopus'' (dro-MOE-puss) or running foot, and '' Dimetropus'' (die-MEET-row-puss) or Dimetrodon foot. The trackways can be difficult for the general public to find, as the monument is largely undeveloped with few facilities yet existing to aid fossil hunters. Many of the slabs pulled out by Jerry MacDonald are housed at the

New Mexico Museum of Natural History and Science The New Mexico Museum of Natural History and Science is a natural history and science museum in Albuquerque, New Mexico near Old Town Albuquerque. The Museum was founded in 1986. It operates as a public revenue facility of the New Mexico Departmen ...

, although they are not on display at this time. Guided hikes are periodically offered by BLM interpretive staff.

Geology

The monument lies along the western portion of the

Rio Grande rift The Rio Grande rift is a north-trending continental rift zone. It separates the Colorado Plateau in the west from the interior of the North American craton on the east. The rift extends from central Colorado in the north to the state of Chihuahu ...

and is within part of the

. It is made up of Cenozoic

alluvium Alluvium (from Latin ''alluvius'', from ''alluere'' 'to wash against') is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. ...

and intrusive rock and

Paleozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ' ...

( Hueco Formation) sediments. The Hueco Formation is Early Permian strata. Most of the monument is

Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last ...

and would have been underwater or along the coast of what was once the Hueco Seaway. The tracks can be found in the red rock of the Robledo Mountains Member of the Hueco Formation.

Flora and fauna

The monument is situated at the northern tip of the

Chihuahuan Desert The Chihuahuan Desert ( es, Desierto de Chihuahua, ) is a desert ecoregion designation covering parts of northern Mexico and the southwestern United States. It occupies much of far West Texas, the middle to lower Rio Grande Valley and the lo ...

. Some examples of plants within the monument are

ocotillo ''Fouquieria splendens'' (commonly known as ocotillo (), but also referred to as buggywhip, coachwhip, candlewood, slimwood, desert coral, Jacob's staff, Jacob cactus, and vine cactus) is a plant indigenous to the Sonoran Desert and Chihuahuan ...

mesquite Mesquite is a common name for several plants in the genus '' Prosopis'', which contains over 40 species of small leguminous trees. They are native to dry areas in the Americas. They have extremely long roots to seek water from very far under gr ...

creosote bush ''Larrea tridentata'', called creosote bush and greasewood as a plant, chaparral as a medicinal herb, and ''gobernadora'' (Spanish for "governess") in Mexico, due to its ability to secure more water by inhibiting the growth of nearby plants. In S ...

, prickly-pear cactus, Torrey yucca,

barrel cactus Barrel cacti are various members of the two genera ''Echinocactus'' and ''Ferocactus'', endemic to the deserts of Southwestern North America southward to north central Mexico. Some of the largest specimens are found in the Sonoran Desert in So ...

sotol Sotol is a distilled spirit from the Chihuahuan desert northern Mexico, western Texas sourced from the family of Asparagaceae; the genus Dasylirion and several species, most commonly: ''Dasylirion wheeleri'', Dasylirion durangense, ''Dasyliri ...

agave ''Agave'' (; ; ) is a genus of monocots native to the hot and arid regions of the Americas and the Caribbean, although some ''Agave'' species are also native to tropical areas of North America, such as Mexico. The genus is primarily known for ...

and snakeweed. A few of the animals that you may see are

mule deer The mule deer (''Odocoileus hemionus'') is a deer indigenous to western North America; it is named for its ears, which are large like those of the mule. Two subspecies of mule deer are grouped into the black-tailed deer. Unlike the related whi ...

rattlesnakes Rattlesnakes are venomous snakes that form the genera '' Crotalus'' and '' Sistrurus'' of the subfamily Crotalinae (the pit vipers). All rattlesnakes are vipers. Rattlesnakes are predators that live in a wide array of habitats, hunting small an ...

desert cottontail The desert cottontail (''Sylvilagus audubonii''), also known as Audubon's cottontail, is a New World cottontail rabbit, and a member of the family Leporidae. Unlike the European rabbit (''Oryctolagus cuniculus''), they do not form social burrow s ...

, many species of lizards, and several species of birds.

Climate

On average the coolest month in the monument is January with an average high of , the hottest month is June with an average high temperature of , and the wettest month is August with about of precipitation.

Discovery

In situ Paleozoic Era tracks were discovered on June 6, 1987 by Jerry Paul MacDonald. Scattered footprints had been found in the Robledos for almost fifty years prior to MacDonald starting his search. He used the recollections of local hikers, quarrymen, and fossil hunters to concentrate his search. This initial site was named the "Discovery Site". It is one of the best places in the monument for visitors to see fossilized tracks. Jerry MacDonald excavated three long trackways, carrying over 2500 slabs out from the site on his back. The majority of the slabs are housed in the

in the Jerry MacDonald Paleozoic Trackways Collection. Two other continuous trackways are held in the

Carnegie Museum of Natural History The Carnegie Museum of Natural History (abbreviated as CMNH) is a natural history museum in the Oakland neighborhood of Pittsburgh, Pennsylvania. It was founded by Pittsburgh-based industrialist Andrew Carnegie in 1896. Housing some 22 million ...

and Smithsonian.

Monument designation

Prehistoric Trackways National Monument was sponsored by Senators

Jeff Bingaman Jesse Francis "Jeff" Bingaman Jr. (born October 3, 1943) is an American politician who served as a United States Senator from New Mexico from 1983 to 2013, for 5 terms. A member of the Democratic Party, he served as Chairman of Committee Outrea ...

(D-NM) and

Pete Domenici Pietro Vichi "Pete" Domenici (May 7, 1932 – September 13, 2017) was an American attorney and politician who served as a United States Senator from New Mexico from 1973 to 2009. A member of the Republican Party, he served six terms in the S ...

(R-NM) and was part of the

National Landscape Conservation System National Conservation Lands, formally known as the National Landscape Conservation System, is a collection of lands in 873 federally recognized areas considered to be the crown jewels of the American West.United States of America The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territo ...

under the

Omnibus Public Land Management Act The Omnibus Public Land Management Act of 2009 (, ) is a land management law passed in the 111th United States Congress and signed into law by President Barack Obama on March 30, 2009. The bill designates millions of acres in the US as protected a ...

, signed into law on March 30, 2009. It was the first national monument established under the

Barack Obama Barack Hussein Obama II ( ; born August 4, 1961) is an American politician who served as the 44th president of the United States from 2009 to 2017. A member of the Democratic Party, Obama was the first African-American president of the ...

administration, and the fourth established in 2009. At the time of its establishment, it was the 100th active national monument in the United States (not the 100th national monument ever designated, since some monuments were previously designated and later dissolved, but the 100th national monument still in operation). Discovery Site

Recreation

The Bureau of Land Management is in the process of writing a resource management plan for the monument to be completed in 2012. In the meantime, there are no developed hiking or equestrian trails, and only one interpretive sign. Roads are not maintained and there are no facilities. There are OHV and mountain bike trails, which are rugged and require appropriate skills and equipment.

References

External links

Official Bureau of Land Management website

Book in PDF. on monument

10 podcasts on the monument

New Mexico Museum of Natural History and Science

News report on YouTube
{{authority control National Monuments in New Mexico Bureau of Land Management National Monuments Bureau of Land Management areas in New Mexico Fossil parks in the United States Fossil trackways in the United States Paleozoic life Paleozoic New Mexico Protected areas of Doña Ana County, New Mexico 2009 establishments in New Mexico Protected areas established in 2009 National Monuments designated by Barack Obama Units of the National Landscape Conservation System Paleontology in New Mexico