{{short description|National monument in New Mexico, United States}} {{Use American English|date=July 2025}} {{Use mdy dates|date=February 2025}} {{Infobox protected area | name = Prehistoric Trackways National Monument | image = Prehistoric-trackways-01.gif | mapframe = yes | mapframe-zoom = 10 | mapframe-wikidata = yes | map = New Mexico#USA | relief = 1 | map_caption = Location of Prehistoric Trackways National Monument within the United States | location = Doña Ana County, NM, USA | nearest_city = Las Cruces, New Mexico | coordinates = {{coord|32|21|0|N|106|54|0|W|region:US|format=dms|display=inline,title}} | coords_ref = | area = {{convert|5,255|acre|0}}<ref name="blm_details">{{BLM National Monument detail table |accessdate=2012-12-27}}</ref> | established = March 30, 2009 | visitation_num = | visitation_year = | visitation_ref = | governing_body = Bureau of Land Management | website = [https://www.blm.gov/visit/ptnm Prehistoric Trackways National Monument] | module = {{designation list | embed = yes | designation1 = NMON | designation1_date = }} }}
'''Prehistoric Trackways National Monument''' is a national monument in the Robledo Mountains of Doña Ana County, New Mexico, United States, near the city of Las Cruces. The monument's Paleozoic Era fossils are on {{convert|5,255|acre|0}}<ref name="blm_details"/> of land administered by the Bureau of Land Management.<ref name="blm.gov">{{cite web |date=May 31, 2011 |title=Prehistoric Trackways National Monument |publisher=Bureau of Land Management |url=http://www.blm.gov/nm/st/en/prog/recreation/las_cruces/trackways.html |access-date=August 4, 2011 |archive-url=https://web.archive.org/web/20110831213342/http://www.blm.gov/nm/st/en/prog/recreation/las_cruces/trackways.html |archive-date=August 31, 2011 |url-status=dead }}</ref> 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 fossilized footprints in fossil mega-trackways of land animals, sea creatures, and insects. These are known as trace fossils or ichnofossils. There are also fossilized plants and petrified wood present, as well as plenty of marine invertebrate fossils including brachiopods, gastropods, cephalopods, bivalves, and echinoderms.<ref>{{cite journal |last1=Kozur |first1=Heinz W. |last2=LeMone |first2=David V. |year=1995 |title=The Shalem colony Section of the Abo and Upper Hueco Members of the Hueco formation of the Robledo Mountains, Dona Ana County, New Mexico: Stratigraphy and New Conodont Based Age Determinations |journal=New Mexico Museum of Natural History and Science Bulletin |volume=6 |pages=39–55}}</ref> Much of the fossilized material originated during the Permian Period and is around 280 million years old.<ref name="blm.gov"/>
[[File:Dimetrodon track.jpg|thumb|upright=1.2|left|Possible ''Dimetrodon'' track]] Some of the animals who may have left tracks in the Robledo Mountains include ''Dimetrodon'', ''Eryops'', ''Edaphosaurus'', and multiple other pelycosaurs.<ref>{{cite book |last=Lockley |first=M. |year=1995 |title=Dinosaur tracks: and other fossil footprints of the western United States |location=New York |publisher=Columbia University Press |isbn=978-0231079266}}</ref><ref name=":0">{{Cite web |last=Lucas |first=Spencer |date=2015 |title=New Mexico Museum of Natural history and science 2015 bulletin |url=https://npshistory.com/publications/blm/prehistoric-trackways/nmmnhsb-65-2015.pdf}}</ref> There are at least 13 major trace fossils found at the monument, including ''Selenichnites'' (sel-EEN-ick-NIGHT eez) or moon-shaped trace, ''Kouphichnium'' (koof-ICK-nee-um) or light trace, ''Palmichnium'' (pal-ICK-nee-um) or palm [frond] trace, ''Octopodichnus'' (oct-toe-pod-ICK-nuss) or eight-footed trace, ''Lithographus'' (lith-oh-GRAFF-us) or rock writing, ''Tonganoxichnus'' (tong-a-nox-ICK-nuss) or Tonganoxie [Kansas] trace, ''Augerinoichnus'' (aw-gurr-EE-no-ICK-nuss) or Augerino 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.<ref>{{cite book |last=Lucas |first=S. |year=2011 |title=Traces of a Permian Seacoast |location=Albuquerque |publisher=New Mexico Museum of Natural History |isbn=978-0615471709}}</ref>
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, although they are not on display at this time. Guided hikes are periodically offered by BLM interpretive staff.<ref name="blm.gov"/>
==Geology== The monument lies along the western portion of the Rio Grande rift and is within part of the Robledo Mountains. It is made up of Cenozoic alluvium and intrusive rock and Paleozoic (robledo mountain formation) sediments.<ref name="Minter">{{Cite journal |last=Minter |first=Nicholas |date=2009-01-01 |title=Ichnology of an Early Permian Intertidal Flat: The Robledo Mountains Formation of Southern New Mexico, USA |url=https://www.academia.edu/1236904 |doi=10.1111/J.1475-4983.2009.00911.X |doi-broken-date=April 8, 2026 }}</ref> The Robledo Mountain Formation is Early Permian in age, specifically late wolfcampian (Late Artinskian) around 286 million years old.<ref>{{Cite web| title=Prehistoric Trackways National Monument Science Plan | url-status=live | url=https://npshistory.com/publications/blm/prehistoric-trackways/sp-2019.pdf | archive-url=https://web.archive.org/web/20220704213046/http://npshistory.com/publications/blm/prehistoric-trackways/sp-2019.pdf | archive-date=2022-07-04}}</ref><ref name="Minter"/> Most of the monument is Permian 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.<ref>{{cite journal |last=Lucas |first=S. G. |title=Geology of Early Permian tracksites, Robledo Mountains, south-central New Mexico |journal=New Mexico Museum of Natural History and Science Bulletin |year=1995 |volume=6 |pages=13–32|display-authors=etal|url=https://books.google.com/books?id=aY8ZCgAAQBAJ&dq=Lucas,+S.+G.%3B+et+al.+%22Geology+of+Early+Permian+tracksites,+Robledo+Mountains,+south-central+New+Mexico%22.+New+Mexico+Museum+of+Natural+History+and+Science+Bulletin.+6:+13%E2%80%9332.&pg=PA13 |access-date=15 April 2022}}</ref> The rocks of the Robledo Mountains Formation interfingers with the fossil rich Abo Formation.<ref name=":0" /><ref>{{Cite web |last=Lucas |first=Spencer |date=2025 |title=THE LOWER PERMIAN HUECO GROUP AND ABO FORMATION IN SOUTHERN NEW MEXICO AND HUECO GROUP CORRELATIONS IN NEW MEXICO-WEST TEXAS |url=https://www.researchgate.net/publication/396539837}}</ref><ref>{{Cite web |last=Kues |first=Barry |date=2004 |title=the late paleozoic ancestral rocky mountains system in new mexico |url=https://www.researchgate.net/publication/288940743}}</ref> This means the units represent laterally equivalent and contemporary environments. The Abo Formation has produced body fossils of ''Dimetrodon'',''Edaphosaurus,Eryops'' and numerous other vertebrates.<ref>{{Cite journal |last=Krainer |first=Karl |date=2024-11-26 |title=The Lower Permian Abo Formation in the Northern Sacramento Mountains, Southern New Mexico |url=https://www.academia.edu/48022871}}</ref><ref>{{Cite web |last=Lucas |first=Spencer |date=2012 |title=The Lower Permian Abo Formation in the Fra Cristobal and Caballo Mountains, Sierra County, New Mexico |url=https://nmgs.nmt.edu/publications/guidebooks/downloads/63/63_p0345_p0376.pdf}}</ref><ref>{{Cite web |title=Page 76 |url=https://nmdigital.unm.edu/digital/collection/bulletins/id/4550 |access-date=2026-04-04 |website=nmdigital.unm.edu |language=en}}</ref> This indicates the animals of the Abo Formation were the likely track makers at PTNM.
==Flora and fauna== The monument is situated at the northern tip of the Chihuahuan Desert. Some examples of plants within the monument are ocotillo, mesquite, creosote bush, prickly-pear cactus, Torrey yucca, barrel cactus, sotol, agave and snakeweed. A few of the animals that you may see are mule deer, rattlesnakes, desert cottontail, many species of lizards, and several species of birds.<ref>{{cite web |url=http://www.chihuahuandesert.org/fieldguide2.htm |title=Chihuahuan Desert Field Guide - Plants |publisher=Chihuahuan Desert Education Coalition |access-date=2012-12-27 |url-status=dead |archive-url=https://web.archive.org/web/20130221044445/http://www.chihuahuandesert.org/fieldguide2.htm |archive-date=2013-02-21 }}</ref>
==Climate== On average the coolest month in the monument is January with an average high of {{convert|57|F|C}}, the hottest month is June with an average high temperature of {{convert|94|F|C}}, and the wettest month is August with about {{convert|2.52|in}} of precipitation.<ref>{{cite web |url=http://www.weather.com/outlook/recreation/outdoors/overview/US0875 |title=Overview for Robledo Mountains |publisher=The Weather Channel |access-date=2011-08-06 |url-status=dead |archive-url=https://web.archive.org/web/20121024195518/http://www.weather.com/outlook/recreation/outdoors/overview/US0875 |archive-date=2012-10-24 }}</ref>
==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 New Mexico Museum of Natural History and Science in the Jerry MacDonald Paleozoic Trackways Collection. Two other continuous trackways are held in the Carnegie Museum of Natural History and Smithsonian.<ref>{{cite book |last=MacDonald |first=J. |year=1994 |title=Earths First Steps |location=Boulder Co. |publisher=Johnson Printing |isbn=978-0585036632}}</ref>
==Monument designation== Prehistoric Trackways National Monument was sponsored by Senators Jeff Bingaman (D-NM) and Pete Domenici (R-NM) and was part of the National Landscape Conservation System of the United States of America under the Omnibus Public Land Management Act, signed into law on March 30, 2009.<ref>{{cite web |author=United States Congress |title=Omnibus Public Land Management Act of 2009, Title II |date=October 3, 2009 |url=http://en.wikisource.org/wiki/Omnibus_Public_Land_Management_Act_of_2009/Title_II |access-date=2012-12-27}}</ref> It was the first national monument established under the Barack Obama 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). thumb|250px|right|BLM sign at the discovery site
==Recreation== {{update section|date=September 2020}} OHV, horseback riding and mountain biking is permitted along the designated paths and hiking as well as camping can be done along informal trails across the desert.<ref>{{Cite web |title=Prehistoric Trackways National Monument |url=https://www.blm.gov/visit/ptnm |access-date=2026-02-25 |website=Bureau of Land Management |language=en}}</ref>
==See also== * List of national monuments of the United States * Walchia * Fossil trackways in the United States * Organ Mountains–Desert Peaks National Monument * White Sands National Park
==References== {{Reflist}}
==External links== *[https://www.blm.gov/visit/ptnm Official Bureau of Land Management website] * [https://web.archive.org/web/20120126023613/http://www.blm.gov/pgdata/etc/medialib/blm/nm/programs/recreation/rec_docs/rec_docs_las_cruces.Par.30343.File.dat/TracesofaPermianSeacoast_smallerfilesize.pdf Book in PDF. on monument] * [https://www.youtube.com/blmnewmexico/ 10 podcasts on the monument] * [https://nmnaturalhistory.org/ New Mexico Museum of Natural History and Science] * [https://www.youtube.com/watch?v=1rpsiY4Pb4w/ News report on YouTube]
{{Protected Areas of New Mexico}} {{National Monuments of the United States}}
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Category:National monuments in New Mexico Category:Bureau of Land Management national monuments Category:Bureau of Land Management areas in New Mexico Category:Fossil parks in the United States Category:Fossil trackways in the United States Category:Paleozoic life Category:Paleozoic New Mexico Category:Protected areas of Doña Ana County, New Mexico Category:2009 establishments in New Mexico Category:Protected areas established in 2009 Category:National monuments designated by Barack Obama Category:Units of the National Landscape Conservation System Category:Paleontology in New Mexico