The Robledo Mountains are a mountain range

Mountain range

A mountain range is a single, large mass consisting of a succession of mountains or narrowly spaced mountain ridges, with or without peaks, closely related in position, direction, formation, and age; a component part of a mountain system or of a mountain chain...

 in Doña Ana County, New Mexico

Doña Ana County, New Mexico

-2010:Whereas according to the 2010 U.S. Census Bureau:*74.1% White*1.7% Black*1.5% Native American*1.1% Asian*0.1% Native Hawaiian or Pacific Islander*3.0% Two or more races*18.5% Other races*65.7% Hispanic or Latino -2000:...

 just northwest of Las Cruces

Las Cruces, New Mexico

Las Cruces, also known as "The City of the Crosses", is the county seat of Doña Ana County, New Mexico, United States. The population was 97,618 in 2010 according to the 2010 Census, making it the second largest city in the state....

. The range was named for Pedro Robledo, who died on May 21, 1598 and was buried nearby. Robledo was the first casualty of the Oñate expedition to colonize the upper Rio Grande

Rio Grande

The Rio Grande is a river that flows from southwestern Colorado in the United States to the Gulf of Mexico. Along the way it forms part of the Mexico – United States border. Its length varies as its course changes...

 valley. A native of Toledo, Spain

Toledo, Spain

Toledo's Alcázar became renowned in the 19th and 20th centuries as a military academy. At the outbreak of the Spanish Civil War in 1936 its garrison was famously besieged by Republican forces.-Economy:...

, Robledo was accompanied on the expedition by his wife and five children.

These Mountains are home to world famous Early Permian

Permian

The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...

 trackways of invertebrates and vertebrates. The main locality was recently designated the 100th active national monument

National monument

A National monument is a monument constructed in order to commemorate something of national importance such as a war or the country's founding. The term may also refer to a specific monument status, such as a National Heritage Site, which most national monuments are by reason of their cultural...

 in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, and named Prehistoric Trackways National Monument

Prehistoric Trackways National Monument

Prehistoric Trackways National Monument is the 100th national monument in The United States of America. The monument is located in the Robledo Mountains, near Las Cruces in the southern region of the U.S. state of New Mexico...

. Rock outcrops in the area preserve numerous examples of Early Permian

Permian

The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...

 trackways

Trace fossil

Trace fossils, also called ichnofossils , are geological records of biological activity. Trace fossils may be impressions made on the substrate by an organism: for example, burrows, borings , urolites , footprints and feeding marks, and root cavities...

. These trackways include prints of Dimetrodon

Dimetrodon

Dimetrodon was a predatory synapsid genus that flourished during the Permian period, living between 280–265 million years ago ....

, Edaphosaurus

Edaphosaurus

Edaphosaurus is a genus of prehistoric synapsid which lived around 303 to 265 million years ago, during the late Carboniferous to early Permian periods. The name Edaphosaurus means "ground lizard" and is derived from the Greek edaphos/εδαφος and σαυρος/sauros...

, Eryops

Eryops

Eryops meaning "drawn-out face" because most of its skull was in front of its eyes is a genus of extinct, semi-aquatic amphibian found primarily in the Lower Permian-aged Admiral Formation of Archer County, Texas, but fossils are also found in New Mexico and parts of the eastern United...

, Cacops

Cacops

Cacops is a genus of dissorophid temnospondyl that is known from the Early Permian of the central United States.It was about long and well adapted to a terrestrial lifestyle, with a heavily built skull, strong legs, a short tail, and a row of armor plates along its back...

 and many other small pelycosaurs.