Geology of the Jemez Area, Chapter 13: The Holocene

The table of contents may be found here.

Tyuonyi ruins
Tyuonyi Ruin at Bandelier National Monument. Looking south from 35 47.121N 10616.585W

We do not know exactly when the first humans settled in the Jemez area. Humans, Homo sapiens, are a relatively young species; the genus Homo is thought to have emerged perhaps 2.8 million years ago, close to the start of the Quaternary, and Homo sapiens is perhaps 200,000 years old. The first humans to cross over the Bering Straits into North America arrived somewhere between 40,000 and 16,000 years ago. The oldest human artifacts in New Mexico, discovered at Clovis, are around 13,500 years old, or near the start of the Holocene.

In this chapter, we emerge from deep time into the Holocene, the age of historic Man.

  1. Humans settle the Jemez
    1. Paleoindians
    2. Archaic and Ancestral Puebloans
      1. Trails
      2. Petroglyphs
      3. Obsidian
    3. The Spanish era
      1. Canones
      2. Missions and sanctuaries
    4. The American era
      1. Cattle ranching
      2. Logging
      3. Mining
      4. Ghost Towns
      5. Los Alamos
      6. Geothermal prospecting
      7. Movies
  2. The Jemez Today
    1. The Valles Caldera National Preserve
    2. Bandelier National Monument
    3. Kashe-Katuwe National Monument
    4. Santa Fe National Forest
      1. Forest Road 289 (Dome Road)
      2. Forest Road 36
      3. State Road 290/Forest Road 10
      4. Forest Road 266
      5. State Road 485/Forest Road 376
      6. State Road 126
      7. Forest Road 100
      8. Forest Road 144 (Thirtyone Mile Road)
    5. Hazards
      1. Lightning
      2. Flash flooding
      3. Water and sunshine
      4. Critters
      5. Volcanic Activity
  3. Geological History Animations

Humans settle the Jemez

Road to
          Kiatsukwa ruins
Old road to Kiatsukwa Ruins


The oldest archaeological sites in the Jemez date back about 11,000 years and consist of obsidian quarry sites and isolated structures called field houses. These reflect a culture that was still largely a hunter-gatherer culture that characteristically hunted big game. At this time, New Mexico had a significant population of megafauna, or large mammals, such as mammoths, musk oxen, mastodons, and camels, and their predators, lions and saber-tooth tigers. The megafauna abruptly disappeared around 10,900 B.C. for reasons still not agreed among archaeologists, though over-hunting by paleoindians is widely thought to have played an important role.

Among the last of the paleoindians was the Cody culture, which hunted along the major rivers of New Mexico around 7500 B.C. Climate change drove the Cody out of the area within two millennia.

Archaic and Ancestral Puebloans

The Archaic people arrived on the Rio Grande around 5500 BC and were the first farming culture of New Mexico. The earliest flint tool found in the Cerro Pedernal region is characteristic of the Bajada Phase, 4800 to 3200 B.C.  

Maize (Indian corn) appeared around 2100 B.C. and was the major crop by 500 A.D. Beans and squash may have arrived around 1000 B.C., while cotton became a crop around 400 A.D. These were farmed using dry land farming methods that relied on rainfall, which is more abundant at higher elevations.

By 1150 A.D., the first permanent communities began to be established in the Jemez, by what are now known as the Ancestral Puebloans. (The older term "Anasazi" is considered a pejorative by the modern Puebloans and its use is discouraged.)  These settlers likely included the principal ancestors of the Keresians, who now live in the southern Jemez pueblos of Cochiti, Santo Domingo, San Felipe, Zia, and Santa Ana, as well as the more distant pueblos of Acoma and Laguna. The remains of their settlements are found throughout the periphery of the Jemez and are particularly well known at Bandelier and Puye Cliffs. The large settlement found within the Valles caldera itself was in Valles de los Indios, a relatively sheltered location, and a few field houses on the south slopes of Banco Bonita. The remainder of the caldera can become very cold in the winter due to its topography forming a natural trap for cold air. This makes it unsuitable for maize culture. Pottery shards in the caldera are few but diverse, suggesting that the caldera was regularly visited by almost all the neighboring cultures.

In addition to establishing large permanent settlements, the Ancestral Puebloans produced pottery, of a type archaeologists describe as Red Mesa black-on-white.

Red Mesa black-on-white pottery
Red Mesa black-on-white storage jar. Wikimedia Commons

Although some of the Ancestral Puebloans adopted Ak Chin farming, which utilizes runoff to water fields, the only culture of this period to adopt true irrigation was the Chacoan, which flourished between 1020 and 1125 A.D. in the San Juan Basin northwest of the Jemez. The Chacoan civilization constructed sophisticated irrigation systems and built large masonry cities, but seem to have had no written language, nor are there any indications that they smelted the fragments of metal ore found around their settlements, apparently prizing them instead for their ornamental value. Turquoise was particularly prized and turquoise beads have been found in pecked basins (excavated circular pits, about a foot across and half as deep) atop the nearby mesas, which are believed to have been offerings to the gods. The civilization abruptly collapsed around 1130 A.D. Possible causes include drought or civil war; infant mortality appears to have been nearly twice as great in the outlying areas as in the central cities, pointing to increasing social stratification. Regardless of the actual cause, the collapse of the Chacoan civilization seems to have left the ancestral Puebloans with a deep distrust of attempts to control nature.

Pueblo Bonita
Pueblo Bonita, center of the Chaco civilization. 36 03.710N 107 57.764W

The migration of the survivors of the disaster to higher elevations also produced conflict, and may account for the tendency of pueblos in the Jemez to be located atop more easily defended mesas than in the more fertile valleys. This period, from about 1130 AD to 1325 AD, is known as the Coalition period and is characterized by the appearance of new patterns of pottery. The Chacoans may have been the principal ancestors of the Tewa or Tano peoples, who today live in the Rio Grande Valley north of Santa Fe at the pueblos of Nambé, Pojoaque, San Ildefonso, Ohkay Owingeh, Santa Clara, and Tesuque.

Ruins of field house on Burnt Mesa. 35 49.046N 106 19.261W

The oldest settlements on the Pajarito Plateau date back to about the 13th century and were relatively small and located mostly at altitudes below 6800' (2000m). Each settlement had ten to twelve rooms arranged in two rows, usually laid out north to south. Only two or three rooms had fire pits, and the others may have been for storage. Perhaps two or three families occupied each settlement. The construction was tuff blocks at the bottom of the walls, often giving way to packed adobe towards the top, 

          house near Fuller Lodge

Ruins of field house near Fuller Lodge in Los Alamos. 35 52.979N 106 18.096W

Scores of such ruins are found on the larger mesas, but archaeologists believe only a few were occupied at any given time.

Map of prehistoric Jemez ruins

Map of multiple dwelling Ancestral Puebloan ruins in the Jemez

Archaeologists refer to the period from about 1325 AD to 1600 AD as the Classical Period. The population began gathering into larger settlements in the 15th century, and by the end of that century there were a number of much larger population centers. One of these is Kiatsukwa Pueblo ruins, located near 35 44.000N 106 36.971W. This is easily accessible from Forest Road 10, but if you choose to visit, be respectful of the area, disturb nothing, and take no samples (even of natural rocks.) The ruins are strictly protected under the Antiquities Act.

Note the many large branches laid deliberately along the road to the ruins. This was likely done by the Forest Service to control erosion along the road and allow vegetation to grow back, but the branches also discourage casual visitors to the ruins.

Road to
          Kiatsukwa ruins
Old road to Kiatsukwa Ruins

Large boulders have also been placed at the junction with Forest Road 10 to block vehicular movement. I repeat: If you visit, take only photographs, and do not disturb the ruins in any way.

The ruins are largely unexcavated and consist of mounds of roughly shaped blocks of Bandelier Tuff. The site was occupied between 1400 and 1500 A.D. and briefly reoccupied in the early 1600s.

Kiatsukwa ruins

Kiatsukwa ruins
Kiatsukwa Ruins

The pueblo numbered about 400 persons at its peak, with some buildings having three levels. The valley here is underlain by El Cajete Pumice, which seems to have been favored by the Ancestral Puebloans for its fertility and capacity to hold water. The pumice is evident in the soil along the road.

          exposures of El Cajete Pumice
Kiatsukwa Ruins

Archaeologists at Bandelier National Monument have made attempts to reproduce ancestral Puebloan agricultural practices.

Experimental garden
Experimental garden. 35 47.721N,106 17.002W

The corn here is of a variety resembling those used by Ancestral Puebloans, and relies solely on rainwater and snow melt. The soil here, atop Burnt Mesa northeast of Frijoles Canyon, is rich in El Cajete Pumice.

Another important ruin is Otowi, located in Pueblo Canyon east of Los Alamos. The site is easily seen from the Clinton P. Anderson Overlook, being located directly to the north on a ridge on the canyon floor.

Otowi Ruins
Otowi Ruins. Looking north from 35 52.386N 106 14.006W

This ruin is completely unexcavated and likely to remain so, since it is on tribal lands of the descendants of the people who lived here. However, the ground has a characteristic appearance in the satellite photograph that is partially discernible at ground level.

Tsankawi is the site of another large unexcavated ruin.

Tsankawi ruins

Eastern edge of Tsankawi ruins. 35 51.705W 106 12.895W

There are a number of archaeological sites around the world that have been left deliberately unexcavated like this. In some cases, it is out of respect for the feelings of identifiable descendants of the peoples of the ruins who are leery of having their ancestors’ ancient homes poked around. But in other cases, it is because the ruins are typical of a culture that has already been much studied, and are being left unexcavated against the day when better methods of excavation are invented. In the case of Tsanwaki, I suspect both reasons apply.

I also noticed that the visible edge of the ruins on the ground are well within the area that looks visibly disturbed on satellite. I have no ready explanation.

Within the ancient walls are at least two pits that are likely unexcavated kivas.


Kivas at Tsankawi. 35 51.727W 106 12.930W

Kivas were the underground ceremonial spaces of the Ancestral Puebloans. The classical kiva is a round room, roofed over, with a small pit on the north side (a sipapu) which likely represented the doorway from which the first humans emerged from the underworld. Kivas are interpreted by some archeologists as models of the Universe, where heaven, earth and the underworld meet — as with temples in many ancient cultures.

Possibly related are so-called circle shrines.

Circle shrine

Circle shrine on Burnt Mesa. 35 47.166N 106 16.658W

I have been warned that archaeologists have a tendency to interpret anything whose practical purpose is not obvious as a religious artifact. However, members of some native American tribes still make use of stone shrines for activities that are clearly religious in character, and stone circles have been associated with native American communities from the Chaco civilization to the early Spanish era at Petroglyphs National Monument in Albuquerque.

In addition to walled villages and individual field houses, the Ancestral Puebloans excavated caveate rooms in cliffs of the relatively soft tuff of the Bandelier Formation.

Here is a caveate room with a kind of atrium excavated along the trail to the top of Tsankawi Mesa.

Caveate room with atrium

Caveate room with atrium at Tsankawi. 35 51.673N 106 13.134W

The shape of the atrium appears to have been largely determined by natural jointing in the rock, but the faces were probably smoothed off and the row of holes then excavated to seat timbers supporting a light roof. The opening to the left is into a caveate room, which likely started as a natural cavity in the rock that was further excavated by the Ancestral Puebloans. These people came to the area in the 15th century and were speakers of the Tewa language, rather than the Keres language of the settlements in the main section of Bandelier National Monument to the southwest.

The south side of Los Alamos Mesa, north of Tsankawi, shows numerous caveate rooms.

Caveate rooms on Los Alamos Mesa

Caveate rooms on south side of Los Alamos Mesa. Looking north from 35 51.950N 106 13.560W

The caveate rooms are located right at the top of the talus slope below the vertical cliffs. They probably started as small natural cavities in the rock, but were greatly enlarged by the Ancestral Puebloans. There are also what appear to be rows of pits suitable for inserting beams to support a light roof.

The area was probably wetter in the 15th century. There is abundant archeological evidence that the Ancestral Puebloans abandoned many settlements in what are now quite dry areas of the Southwest at about this time and moved to the valleys of the Rio Grande and its major tributaries, where their descendants live today.

The ruins at P'oshu'owingeh ("village above the muddy river") may represent an early stage in this migration to the river valleys.

P'oshu'owingeh ruins

P'oshu'owingeh. Looking north from 36.2113733N 106.275371W

These ruins are largely unexcavated, but the bare ridges mark where the walls once stood. It is estimated that this pueblo once stood 3 or 4 stories tall and had 700 rooms.

The ruins here are on a river terrace overlooking the Chama River. The same terrace level is visible just across the valley. More distant, at the foot of Sierra Negra at the center of the panorama, is another remarkably level erosional surface at a higher level. This was formed in a side channel of the Rio Chama earlier than the the lower terraces. It’s hard to get good estimates of ages of these surfaces, but the higher, older surface is probably about half a million years old. Sierra Negra behind it is capped by a basalt flow that has been dated at 4.5 million years old, showing the age of the surface on which the flow erupted, clear at the top of the mesa. (The rest of the surface has long eroded away.) There has a lot of erosion here in the last five million years.

The establishment of relatively large settlements did not end the use of field houses. Over one hundred field houses have been found in the Frijoles quadrangle alone, which takes in most of Banderlier National Monument and the LANL test ranges to the north.


Other traces of early humans in the Jemez include trails or steps cut into the relatively soft tuff of the Bandelier Formation. There are a pair of likely prehistoric steps in the tuff above the Clinton P. Anderson Overlook.

          exposures of El Cajete Pumice
Prehistoric steps. Near 35.872N 106.234W

This area saw some modern traffic in the 1940s, when the old road to Los Alamos made switchbacks up the nearby mesa face. However, the new road is further away, and it it unlikely these are modern traces.

There are prehistoric trails carved deeply into the Bandelier Tuff in several locations.

          exposures of El Cajete Pumice
Prehistoric trail on Potrillo Mesa. Near 35.795N 106.221W

This is located on Potrillo Mesa south of White Rock and is now used by the occasional modern hiker. Similar trails are prominent in the Tsankawi section of Bandelier National Monument.

Trail on Tsankawi mesa

Prehistoric trail at Tsankawi. 35 51.732N 106 13.044W

The desert varnish visible in the trail shows its antiquity. The fact that the desert varnish has not been worn away shows that most modern tourists walk on the higher ground around the trail rather that in the trail. This seems most natural.

So why, then, did the Native Puebloans even create this trail?


Among the traces left by the Ancestral Puebloans are petroglyphs. These are markings etched into stone, found scattered throughout the southwestern United States. A large number of petroglyphs are found on the eastern escarpment of the Cerros del Rio near the village of La Cieneguilla.

La Cieneguilla petroglyphs. 35.605N 106.126W

The petroglyphs in this area are on hawaiite that has a thick weathering film, known as desert varnish. When the surface is pounded with a heavy tool, the desert varnish is removed and the lighter rock beneath is exposed. Such petroglyphs can be roughly dated from the extent to which fresh desert varnish has begun to form over the petroglyphs, and this establishes that the petroglyphs were etched by Ancestral Puebloans.

I know little about petroglyph iconography. But then, neither do archaeologists, who have a number of conflicting notions about their significance. For example, the spiral pattern seen in the last photograph is often interpreted as a representation of the sun, but it has also been interpreted as a representation of water or of migration. Some other figures have fairly clear meanings.

The figure at center with the head appendages (probably representing feathers) is Kokopelli, a fertility deity shared across several native American cultures. Kokopelli may have originally represented a kind of wandering priest whose flute was a symbol that he came in peace. Kokopelli has been thoroughly commercialized in the modern American Southwest, which I find vaguely regrettable.

Thunderbird petroglyph

La Cieneguilla petroglyphs. 35.604N 106.124W

The bird-like figure right of center is the thunderbird, a powerful supernatural being in many Native American traditions. To the left are deer or possibly sheep; if the latter, they must postdate the arrival of the Spanish in New Mexico.


La Cieneguilla petroglyphs. 35.604N 106.124W

This photograph is centered on a somewhat faded maize petroglyph. Maize or Indian corn was the staple of the Ancestral Puebloans and is a common element in their petroglyphs.

I have seen petroglyphs throughout the Jemez area, including petroglyphs carved on Bandelier Tuff and in Mesozoic sedimentary rock. Basalt seems favored but not decisively so. Some petroglyphs are found close to ancient settlements, but I’ve also seen petroglyphs in areas far from any known settlement, including White Rock Canyon and the Hagan Basin.

Petroglyphs are found at several locations along the west rim of White Rock Canyon. Some are likely ancient Native American rock art:

        American rock art

and some are not.

Rock art

The petroglyph in the first photograph not only shows an authentic ancient pattern, but it also shows a thin layer of desert varnish reflecting  its antiquity. This is not present on the modern petroglyph, which also reflects 1960s iconography.

The nearest known ancient ruins to these petroglyphs are at Tshirege and Navawi. Neither ruin has been excavated or is accessible to casual visitors.

Petroglyphs of a subtly different character are found northwest of Abiquiu.


Petroglyphs at Red Wash Canyon northwest of Abiquiu. 36 14.518N 106 22.877W

This is a boulder of Shinarump Formation located at the top of a saddle, a natural focal point for travelers between the Chama River valley to the south and the Arroyo del Cobre to the north.


The Jemez was an important center for the ancient obsidian trade, with the obsidian being used to fashion spear heads and other tools. Obsidian from the Jemez was traded throughout the Southwest, and may have been transported as far as Ohio and Mesoamerica. Important ancient obsidian quarries have been identified at Cerro del Medio, El Rechuelos, the Rabbit Mountain debris flows, Bear Springs, and possibly Paliza Canyon.

While hiking around Cerro la Jara close to the Valles Preserve vistors' center, I came across what is likely an ancient tool fashioning site.


This is a location on the north side of the dome, showing a scattering of obsidian chips on the ground. As we've seen, obsidian and rhyolite form from the same kind of of lava and are often interbedded, but these are isolated chips; the bedrock here is all rhyolite, not obsidian; and these chips are freshly broken, not rounded clasts one would expect if they had eroded out of the local rock. That makes it a fair guess that is this is a tool making site. It is common for prehistoric quarries and tool manufacturing sites to be at separate locations. I was careful not to disturb it, beyond placing a quarter on the spot to provide scale for my photograph and then removing it.

The Spanish era

The first Spanish arrived in the New Mexico area around 1540, ending the three centuries of the Classical Period, but for decades the area remained largely unknown to Europeans. In 1598, King Phillip II of Spain authorized Juan de Oñate to organize a new Spanish province in what is now New Mexico. Oñate crossed the Rio Grande at El Paso and established his headquarters near the confluence of the Rio Chama and Rio Grande south of Black Mesa, at the pueblo of Ohkay Oweenge. Oñate named his new capital San Juan de los Caballeros. At this time, there were about 81 major pueblos and a population of about 100,000 Puebloan people in New Mexico. Sixty years later, there were 31 pueblos with a population of 15,000. The catastrophic decline in population has been attributed to epidemic diseases unwittingly introduced by the Spanish, mistreatment of the Puebloans, raids by migratory tribes who had acquired horses, and drought.

The Spanish reintroduced irrigation, forgotten since the time of the Chacoans, and the acequia or community irrigation canal became the hallmark of Spanish settlements along the Rio Grande and its tributaries. The carrying capacity of the land was not large, even with irrigation, and the Hispanics of northern New Mexico developed a culture of small communities at favorable locations that shared water rights and grazing lands for their cattle. One such community is Canones.


The northern tip of Polvadera Mesa gives a magnificent view of the Canones Creek valley.

Canones area seen from Polvadera Mesa

Canones area from northern Polvadera Mesa. 36 09.723N 106 25.816W

At left in the middle distance is Pueblo Mesa. Beyond is the sloping ground north of Cerro Pedernal, with the cliffs of Mesa Alta on the skyline. The village of Cañones lies in the valley left of center, with a glimmer of Abiquiu Reservoir in the distance. Behind and to the right of Cañones is Cañones Mesa, which merges with the El Alto Plateau at right. The canyon at the bottom right of the panorama is Polvadera Canyon.

Pueblo Mesa has the Ancestral Puebloan ruins of Tsi’pinouinge atop it. This appears on the panorama as a tan patch of clear ground. I’m afraid my camera can’t do it justice. Through my binoculars, I could make out piles of stone blocks covering this area, and a low cliff running through the area that appeared to have doors and post holes excavated in it. There is also some ruined walls further south (left), where a trail comes up to the mesa top. I could not make out the shapes of buildings and kivas from this angle that are visible on satellite.

The satellite photo appears to show a single kiva far from the village. There is evidence that kivas were of more than one type. Archaeologists distinguish between Great Kivas and Chaco-style kivas, with the Great Kivas being larger, more elaborate, and kept further from ordinary dwellings than Chaco-style kivas. Perhaps this outlying kiva was a form of Great Kiva. A similar pattern is seen at Tyuonyi at Bandelier National Monument, where there is a single large outlying kiva (Big Kiva) and three smaller kivas within Tyuonyi ruins itself (only one of which has been fully excavated.)

The name, Tsi’pinouinge, means "village of the flaking stone", referring to the many quarries in the Pedernal Chert nearby. Cerro Pedernal is itself known as Tsi'pin ("flaking stone") or possibly Tzi'iping ("pointed mountain'). This pueblo was the largest and northernmost of all the pueblos of the Classical Period, occupied from 1200 to 1325 AD. It had up to 400 rooms, 16 kivas, and a central plaza. After it was abandoned, the area was occupied only by nomadic Utes until the arrival of the Spanish.

Cañones is a Hispanic village of about 113 persons. Its origins trace back to 1766, when Juan Pablo Martín Serrano was awarded the Polvadera Grant. Serrano was a a wealthy military veteran with a large family, and established a seasonal rancho in the canyon, raising livestock, farming the canyon bottom, and trading with the Utes. Permanent settlement seems to have begun with Juan Bautista Valdez, who bought a grant at the present location of Cañones in 1807.

Cañones is typical of the small Hispanic villages of northern New Mexico, which were traditionally sustained by cattle and sheep ranching and farming. Anthropologists Paul Kutsche and John R. Van Ness have contrasted the Hispanic culture south of the Jemez, which they name the Rio Abajo ("lower river"), from the Hispanic culture north of the Jermez, which they name the Rio Arriba ("upper river"). The Rio Abajo tradition was characterized by large individual land grants, social stratification (patrón and peón) and large-scale sheep herding, while the Rio Arriba tradition, of which Cañones is an example, was characterized by communal land grants, small economies, campanilismo (community spirit), and a fair degree of social equality. An important institution of communities like Cañones is the acequias, or irrigation ditch, which provides abundant irrigation to the canyon bottom: Cañones and Polvadera Creeks provides an ample 33 acre-feet per year of water.

The Spanish community grant or merced came with an obligation to improve and defend the land, or it reverted to the Crown. Land was divided between house plots; irrigable plots of a few acres measured by frontage along the stream; and common land for grazing and gathering food and firewood. The former two categories could be privately owned and sold, but the common land was shared by the community, whose members held a usufruct, or use right, to the common land. This system worked reasonably well for a community engaged in subsistence farming.

The surrounding land can support about one cow per 126 acres at lower elevations, one cow to twelve acres in the best locations at middle elevations, and one cow to 48 acres at higher elevations. Sheet irrigation is used to increase the carrying capacity of pasturage in the immediate area of the village. The frost-free period runs only from around May 24 to September 26, making fruit cultivation and gardening a hit or miss proposition.

The town gained temporary fame in 1966, when the state closed the one-room school and ordered the children to attend school in Coyote, which at the time meant busing the students several miles over a very bad road. The parents refused en masse to send their children to school in Coyote, and the subsequent legal battle seems to have revolved around the issue of whether the parents were acting on legitimate concerns for their children's safety or were using the children to pressure the state into building a better road into the community. The upshot is that the parents were fined for truancy, but the village now has an acceptable paved road.

The residents of Cañones value their privacy; geologists familiar with the area and culture recommend that, if you wish to visit Tsi’pinouinge (which requires a permit from the Coyote ranger station), you should approach the area via a trail from near the point where I took this photograph rather than through Cañones. Please note that I have not hiked this trail and cannot guarantee that I have correctly identified the trailhead.

Missions and sanctuaries

The Spanish culture of northern New Mexico is steeped in Catholicism, and local churches and sanctuaries are important historical landmarks. One such is El Santuario de Chimayo, which one New Mexico State Historian has described as "no doubt the most important Catholic pilgrimage center in the United States." A small chapel was built here in 1810 by Don Bernardo Abeyta, a member of the Penitentes and probably a devotee of the Christ of Esquipulas, a site in Guatemala where the clay is believed to have healing powers. The present chapel was built by 1816 and has become a pilgrimage site for Catholics during Holy Week.


El Santuario de Chimayo. 35 59.336N 105 55.973W

According to legend, the sanctuary marks the site where a buried crucifix was discovered sometime in the 18th century. Accounts vary as to who found the crucifix and under what circumstances. A small room within the sanctuary (el pocito) contains a round pit containing the sand in which the crucifix was found, which is thought to have curative powers. It is traditional for Catholics seeking blessings to walk long distances to the sanctuary and take a small amount of the tierra bendita, "blessed earth."

Ruins of older missions are historically significant, such as Plaza de Santa Rosa de Lima.

Santa Rosa de LIma

Plaza de Santa Rosa de Lima. 36 12.572N 106 17.547W

This is heart of the ghost town of Santa Rosa de Lima. The church was apparently in use until the 1930s and is now on the National Register of Historic Places. The nearby village of Abiquiu, outside the original genízaro merced, has become somewhat gentrified, and there is a bed and breakfast very close by.

The Spanish regarded New Mexico as a backwater buffer province between Mexico and the North American claims of the French, and, later, the Americans. No foreigners were allowed in the territory, trade to Santa Fe was monopolized by Chihuahua, and the province remained deeply impoverished. Although Mexico established a modern scientific mining school, no one knowledgeable about geology visited New Mexico until the Mexican-American War of 1847.

The American era

One of the first Americans in the Jemez region was Josiah Gregg, a trader on the Santa Fe Trail, who published the bestselling Commerce of the Praires in 1844. Gregg was no geologist, but he did notice the presence of large petrified logs in the Galisteo area, which became the first report of fossils in New Mexico. 

When war broke out between the United States and Mexico, the Army of the North invaded New Mexico across the Raton Pass and reached Santa Fe on 18 August 1847 unopposed. With the expedition was Lieutenant William H. Emory, who made the first scientific observations of the geology of the areas through which the Army marched.

The war of 1847 transferred sovereignty over New Mexico to the United States. The Treaty of Guadalupe Hidalgo granted U.S. citizenship to those New Mexicans who chose not to emigrate to Mexico and bound the United States to recognize the land grants made by the Spanish viceroy or his governors that had continued through the Mexican era. Existing water law was initially left intact, and the institution of the acequia has been little disturbed since 1847 and remains in place in many of the villages of northern New Mexico to the present day.

The recognition of existing land grants in 1847 still leaves its mark on modern maps, which often show grant boundaries. Grant boundaries are often also marked by highway signs. The Valles Preserve is marked as Baca Location No. 1 on some older maps, hearkening back to the time when the Baca family owned the land as a former land grant.

My own home in White Rock is located on the former Ramon Vigil Grant, which has an interesting and murky history. This grant was originally awarded to Pedro Sanchez in 1742, who allegedly used forged documents to petition for the grant. The White Rock area was claimed by the San Ildefonso Pueblo as grazing commons, but the pueblo could produce no documents to support their claim, and it became part of the Pedro Sanchez grant. In 1765, the Spanish governor of New Mexico declared the grant abandoned and ordered it to revert to San Ildefonso. However, in 1851, Antonio Sanchez appeared before the Alcalde (municipal magistrate) for San Ildefonso, claimed to be a descendant of Pedro Sanchez, and sold his claim to the land to Ramon Vigil. With the arrival of the U.S. Surveyor-General at the end of 1854, Vigil petitioned for a "good title" to the land, which was awarded in 1860 in spite of key documents being missing or likely forged. The land was eventually condemned for the Manhattan Project in 1943, then sold to private developers in the postwar era for homes for Laboratory employees, which included my father.

Some grants remain largely intact even to the present day. This is particularly true of land grants controlled by native American pueblos, but the Merced del Pueblo de Abiquiu grant, originally awarded around 1750, also remains intact. The grant takes in most of northern El Alto Mesa, and tourists driving in this area will find themselves restricted to roadways until they reach National Forest land further south.

The years just before the Civil War were marked by numerous surveys of the western United States, generally by parties of the well-trained Corps of Topographic Engineers accompanied by civilian scientists. The rest of the country was hungry to learn about the vast new western territories of the United States, and the publication of hundreds of engravings and wood-cuts cost the government better than $100,000, which was real money in the 1850s. It was the 19th century version of Big Science. This effort was interrupted by the war, but resumed afterwards, with Hayden's survey briefly penetrating New Mexico in 1869 and the Wheeler Expedition conducting the first truly systematic and extensive mapping in the 1870s.

The AT&SF Railroad was completed to Santa Fe by 9 February 1880. The "Chili" line became the closest railway to the Jemez, connecting Santa Fe with Denver on 8 January 1887. The line ran from Santa Fe to Buckman, turning north along the Rio Grande and crossing the river at Otowi

Remnants of Chili Line crossing

Remnant of piling for Chili Line, now occupied by a gauging station.

Old rail grade to Chili crossing

Old railroad grade at Otowi crossing. 35 52.552N 106 08.546W

From there the line ran to Espanola, Embudo, and points further north.

The arrival of the railroad accelerated contact between Anglos and Hispanics and native Americans, and also led to increased friction. Different legal traditions were a particular source of difficulty. Some disputes over land grant boundaries continue to the present day. But some of the thorniest disputes came over the issue of partition. With the arrival of the railroad, livestock raised in New Mexico could be shipped to distant and eager markets, and the grazing land held communally by small Hispanic villages suddenly jumped in value. Under the old customs, ownership of this land was nonpartible; that is, one could sell the right to share in the use of this land to a new owner, but the land itself could not be divided up and portions sold. American law had always viewed land as partible, and conflicts arose when Anglo purchasers thought they were purchasing exclusive use of a tract of ground and Hispanic sellers thought they were selling the right to share in the use of the land. American courts tended to side with the American purchasers, which produced lasting bitterness in the Hispanic community.

However, much of the Hispanic community was able to adjust to American legal and political traditions, and today Hispanics hold a substantial fraction of state and local political offices. Native Americans have not fared as well, in part because they now make up less than 10% of the population, and in part because of the greater cultural gap between native Americans and Anglos compared with the cultural gap between Hispanics and Anglos.

The area north and west of the Ramon Vigil Grant and the San Ildefonso Reservation was opened up for homesteading after being surveyed by the Surveyor-General. Both Hispanic and Anglo settlers established homesteads on the Pajarito Plateau.

Homesteader cabin

Romero cabin. 35 52.965W 106 18.101W

The Romero cabin dates to the late 19th century and was relocated to the historical district from its original location on what is now a LANL restricted area.

Cattle ranching

Cattle ranching plays a significant role in the history of the Jemez area, and cattle grazing on National Forest lands remain a part of the Jemez experience today. The Valles preserve is still a working cattle ranch, and historical buildings from the ranch days continue in use by Preserve staff.

Baca ranch

Old ranch headquarters. 35 51.877N 106 31.022W

          guest lodge, "The Octagon"

The Octagon

The building in the second photograph has an octagonal floor plan and was apparently used as a guest lodge.

Cattle grazing on most National Forest lands is by permit based on carrying capacity. The hiker may encounter cattle in most of the more fertile parts of the National Forest areas of the Jemez.

A mooving sight.

In my experience, most such small herds are mixed steers and cows (with calves at the right time of year.) It is well to remember that even cows can be aggressive if provoked severely enough, and that these animals represent considerable wealth to their owners. Treat them with due respect.


During the early part of the 20th century, much of the Jemez was opened to logging, which continues on a reduced scale to the present day. Logging was particularly extensive in the Valles caldera in the 1960s, including in the area around Redondito.

Logging roads east of Redondito

Logging roads east of Redondito. Looking southeast from 35 54.294N 106 33.224W

The angle of the sun highlights the rows of logging roads on the peak.  Most of the old roads in the caldera are now overgrown, but they make an effective network of trails for hikers and mountain bicyclists. However, the roads shown in this photograph are off-limits, as they are in the cultural exclusion zone around Redondito and Redondo Peak, established out of respect for native American beliefs.

Logging brought with it an emphasis on fighting forest fires. It took decades to recognize that this could be counterproductive, by allowing undergrowth and forest litter to build up to the point where fire potential became explosive. Fires in such forests tend to be hot fires that reach the crowns of the trees, with devastating effect. We now have a better understanding of how fire can renew wild lands, burning out excess undergrowth and thinning tree seedlings.

Here’s what a healthy ponderosa forest is supposed to look like.

ponderosa forest

The trees are widely spaced and surrounded by grassland. This is what you get if there are frequent “cool” ground fires to cut down the number of ponderosa saplings and promote the growth of grass. Curiously, this area is likely not a result of allowing grass fires to run their course, but of livestock grazing simulating some of the effects of fire.

With improved understanding of the role of fire, the Forest Service regularly carries out prescribed burns of selected areas of national forest. One such burn went out of control in May 2000, becoming the devastating Cerro Grande fire which destroyed 48,000 acres (19,400 hectares) of forest and over 400 homes in Los Alamos. The decision to carry out the prescribed burn was controversial, since spring is the windy season in the Jemez and the area was bone-dry. However, the Forest Service was concerned that the Cerro Grande area was a tinderbox that could catch fire from lightning strikes at any time as an uncontrolled burn, and took the gamble of risking a preemptive controlled burn -- a gamble that was lost. The devastating Las Conchas fire in 2011, which burned a record 156,293 acres, was a result of wind blowing down power lines in an area that had not experienced fire for decades.

Visitors to the Jemez may encounter signs advising that a controlled burn is in progress or read about plans for controlled burns in local papers. Should you see a smoke plume in the Jemez without any advisory signs or recent notices in the paper, then by all means report it by cell phone. A wildfire is an emergency for which the good faith use of the 911 code is justified.


Mining has played an important role in the history of the Jemez. We have already learned about gold mining in connection with the Bland Monzonite. But mining of copper took place even earlier, and mining of pumice continues to the present day.

The mining industry distinguished between mines, quarries, and borrow pits. A borrow pit is an open pit where gravel and other unconsolidated material is removed for use in road construction or other civil engineering, while a quarry is an open pit where solid rock (rather than any ore it contains) is mined for use as dimension stone. Any excavation for extracting specific ores or other minerals is a mine.

Copper mining likely dates back to the time of the Spanish conquistadores, and copper ores were worked in the Shinarump Formation near Cuba and in Canyon del Cobre ("Copper Canyon") or in the Abo and Yeso Formations in Canon de San Diego. Of these, only the Nacimiento mine has been worked in modern times.

The mine has been worked since at least the 19th century, originally by adits (horizontal tunnels) in the copper-bearing beds. These were shut down during the First World War, due to the wartime labor shortage, and never reopened. Open-pit mining began in the 1960s and continued to 1975, when rich new copper deposits in South America began to be mined. These drove the worldwide price of copper so low that the Nacimiento mine could not longer be profitably worked. A local earthquake at about this time destabilized part of the slope above the open pit, and the costs of stabilizing the slope and continuing to pump water out of the open pit were prohibitive.

In 1984, an attempt was made to extract the ore by in situ leaching using a solution of sulfuric acid. However, the method proved uneconomical. By then some 25,000 gallons of sulfuric acid had been pumped underground. This posed a serious environmental hazard, and in 2007 the Forest Service began remediation, flushing fresh water through the ore body to remove the acid waste and processing it in a series of treatment ponds on the site. The water returned to the watershed is apparently so cleaned up that it meets drinking water standards.

The treatment ponds begin with an anaerobic pond, filled with boulders, in which alcohol is added to feed anaerobic bacteria. The bacteria metabolize the alcohol using oxygen extracted from the sulfuric acid in the leach water, converting the sulfuric acid to hydrogen sulfide. This form of metabolism is called dissimilatory sulfate reduction. The hydrogen sulfide precipitates most of the metal contaminants out of the waste water but gives a distinct stench to the area.

Most copper mines consist of copper sulfides deposited by hydrothermal activity, with a rich cap of copper carbonate minerals (green malachite and blue azurite) formed by oxidation of the upper part of the ore body. The copper mines of the Jemez area are unusual in that the copper minerals were deposited by replacement of organic matter. The copper was leached from overlying formations by groundwater, which then percolated through the underlying sandstone. The copper replaced the organic matter in the sandstone as chalcocite, Cu2S, along with minor amounts of copper carbonates.

This is a large fragment of petrified wood exposed on the east face of the Nacimiento Mine.

Shinarump copper

Copper mineralization at Nacimiento Mine. 35 59.583N 106 53.815W

The main ore body must have been spectacular. The green color is from malachite, while the petrified wood contains a variable amount of black chalcocite. Unfortunately, this can be hard to distinguish from the carbon of the original wood.

Another example:

          mineralization at the Nacimiento Mine

Here is a bit of petrified wood from the tailings dump showing copper mineralization.

Petrified wood from
          Nacimiento Mine

It’s not a large fragment, but in addition to having beautifully preserved grain, you can see that there is some kind of membrane or layer cutting across the grain at intervals of a few millimeters. I am not paleobotanist enough to tell you the significance of this, alas. The fragment is also heavy, suggesting that there is considerable replacement of carbon by chalcocite.

The Nacimiento Mine has been worked long enough for Nature to have done some reworking of her own.

"Blueberries" from
          Nacimiento Mine

These are copper "blueberries" found in some of the tailings and worked areas of the mine. They do not seem to be present in the undisturbed beds, which suggests they have formed in a matter of decades in copper-rich debris exposed to the elements by the mining operations. Whether these should be classified as a natural feature is a matter of semantics; in this case, they formed as a consequence of anthropological disturbance, but they could in principle form in natural landslides as well. Regardless, they are a curiosity of sufficient value to collectors that the best location for collecting them has been duly staked and claimed by a local rock hound.

Even the main ore body at the Nacimiento Mine was mostly quartz sandstone. Rock from the ore body was milled to a fine powder, then the gangue (waste rock) was separated from the ore to produce copper concentrate suitable to be shipped out for refining. This was done by flotation, in which the finely ground mixture of ore and gangue is placed in a tank of water through which air is bubbled. Chalcocite grains readily cling to the bubbles and are floated to the top of the tank, where they are skimmed off and dried as copper ore concentrate. Because much of the ore at the Nacimiento Mine occurs as copper carbonates, special surfactants were developed that, when added to the water in the tank, caused carbonate mineral grains to cling to the bubbles as well, allowing both ore minerals to be separated from the gangue in one operation.

Pumice mining continues in the Jemez area to the present day. The most active mine is the Copar Mine northwest of Espanola.

Copar pumice mine

Copar Mine. Looking east from 36.035674N 106.24034W

The mine here consists of Guaje Pumice (perhaps the most northerly exposure east of the Jemez) under an overburden of Otowi Member, Bandelier Formation. The overburden is stripped and the pumice beneath sorted into trucks for shipment to purchasers. A consequence is that 31 Mile Road is very well maintained to this point, so that the 18-wheelers can safely traverse it in good weather. Beyond the mine, the road abruptly drops in quality, though it is still a good gravel road by the usual National Forest standards.

A limited amount of quarrying has also taken place in the Jemez. An old limestone quarry, exploiting the Madera Formation, is located not far off State Highway 126.

Limestone quarry

Abandoned limestone quarry. 36.000275N 106.739989W

Nearby workings yielded stone used in the Seven Springs area for road embankments. The pond here was once a depression occupied either by a gravel crusher or a Portland cement kiln. The former is more likely.

Cinder is mined at the Cerrito Pelado Mine in the Cerros del Rio.

Ghost Towns

The native Americans were not the only inhabitants to leave ruined settlements in the Jemez area. Ghost towns, most often dating from around the start of the 20th century, are found scattered throughout the region.

The Tsankawi section of Bandelier National Monument includes an early 20th-century ruin known as the Duchess Castle.

Duchess Castle

Duichess Castle. 35 51.945N 106 12.880W

The Duchess Castle was constructed for Vera von Blumenthal and her friend Rose Dougan in 1918. (Vera was actually a baroness, not a duchess, but the name has stuck.) The “castle” was actually living quarters and a school, built to educate the local Pueblo peoples in how to refine their pottery techniques to increase their commercial value and help lift the pueblos out of poverty.

It’s a reminder of the high idealism of European culture that was devastated, along with much of Europe, in the First World War.

Duchess Castle

Duichess Castle. 35 51.945N 106 12.880W

The construction is shaped tuff blocks with mud mortar and some wood beams. The concrete at the base of the walls looks new and was almost certainly added for better preservation by the Park Service.

Traces of the smaller ghost towns may be nothing more than a cluster of old deciduous trees and some old foundation stones, as at the ghost town of Waldo in the Hagan Basin south of the Jemez.


Waldo. 35 26.865N 106 08.553W

Waldo is a bit unusual in that a salvage company purchased the land for the express purpose of recycling the building materials. Other ghost towns are better preserved.

And now you have the answer to the question that has been puzzled over by millions: Where’s Waldo?

Los Alamos

The largest city in the Jemez region came into existence quite abruptly in 1943, on the site of a former boys' school on the Pajarito Plateau. Ashley Pond had purchased the old Ramon Vigil Grant and the Los Alamos Ranch and started the school in 1916, turning management over to A.J. Connell after 1918. The school emphasized rigorous academic preparation for college, physical activity (including wearing shorts and sleeping in screened porches year-round) and strict discipline.

Fuller Lodge was part of the school complex and is now the oldest building in Los Alamos still in use.

Fuller Lodge

Fuller Lodge. 35 52.921N 106 18.161W

Near Fuller Lodge is Ashley Pond, a small pond named after the boys' school founder, that has since been enlarged and developed into the centerpiece of a large park. The pond has its own population of somewhat aggressive ducks and geese.

The school was closed during the Second World War to make way for a secret laboratory for developing the atomic bomb. The homesteaders on the Pajarito Plateau also found their land condemned by the government, and while all were entitled to compensation, several found their entire compensation seized to pay back taxes.

Access to the new laboratory was via a highway bridge at Otowi.

Otowi old bridge

Old Otowi Bridge. 35 52.485N 106 08.616W

The bridge was built in 1924 and remained in use until 1948, when a steel bridge was built at the location of the modern crossing. Nearby is the Edith Warner home, "The House at Otowi Bridge":

          House at Otowi Bridge

The House at Otowi Bridge. 35 52.485N 106 08.616W

Edith Warner befriended the San Ildefonso Tribe, and vice versa, and also became acquainted with the scientists who designed the first atomic bombs at Los Alamos. Otowi was the transfer point for a lot of the more ordinary deliveries to the laboratory, which Warner was paid a small salary to manage.

After the use of atomic bombs on Hiroshima and Nagasaki contributed to ending the war, the laboratory continued research in nuclear energy, eventually becoming a permanent establishment and a major employer in the region, with Los Alamos being effectively a large company town. It remains so today.

Geothermal prospecting

Because there is obviously hot rock not far below the surface here, exploratory geothermal drilling was done in the Jemez during the 1980s. The Baca #1 well was drilled near the road north of Sulfur Springs.

Baca #1
          well pad

Baca #1 well pad. 35.909N 106.612W

The geothermal potential turned out not to be great enough for profitable exploitation. However, the drilling at this and several other well sites contributed significantly to our understanding of the geology of the Valles caldera.


The Jemez area has become a favorite location for filming Western movies and television shows. Several have been filmed on the Valles preserve, and there are also sets in the area north of Cerillos.


Telephoto shot of back of movie set north of Los Cerillos. Looking east from near 35 31.152N 106 06.927W

This is a relatively new set; it was not yet present on Google Maps at the time I took this photograph. You are seeing a set of facades from the rear.

The Jemez Today

Relief map of the Jemez
Digital relief map of the Jemez area. Red and yellow are paved roads; orange are gravel roads. ©2015 Kent G. Budge

The Jemez Mountains are still largely undeveloped, and likely to remain so for the foreseeable future. However, there is a paved highway (NM 4) through the heart of the Jemez and a loop of paved highways around the periphery of the Jemez. The mountains also have a good network of forest roads. While these are gravel roads, the most important are well-maintained and suitable for passenger vehicles in good weather.

The entire Jemez area has been carefully mapped by geologists, and most of the geologic maps are available online from the New Mexico Bureau of Mining and Mineral Resources. Geologic maps are generally based on a topographic map of the mapped area, but show locations of rock formations, faults, and other geological features.  These maps can be invaluable for the serious geology enthusiast visiting an area.

Perhaps the most useful resource for the geology tourist is the extensive sets of road logs for the Jemez area. A road log is a prescribed route with odometer mileages describing geological features along the route. These are best (and most safely!) used by a driver and co-driver. The vehicle's trip odometer is reset at the start of the route, and the driver follows the prescribed route while the co-driver watches the trip odometer and follows the road log to identify interesting geologic features. Extensive road logs have been published for the Jemez area by the New Mexico Geological Society, and some are available online.

The Valles Caldera National Preserve

Cerro La Jara seen from visitors' center
Valles Preserve visitors' center. Looking southwest from 35 51.412N 106 29.459W

The heart of the Jemez, the Valles Caldera, is almost entirely contained within the Valles Caldera National Preserve. A day pass costs you $15, and to drive in the back areas of the caldera, you will also need a back country vehicle permit. This is free with the $15 day pass but only a limited number are issued each day. The gravel roads to the north moat and along the length of the moat are kept in good condition and are suitable for passenger vehicles in good weather.

The trip to the north moat will give you a good view of the topography of the caldera, caldera rim, ring domes, and resurgent dome.

Bandelier National Monument

The southeast portion of the Jemez is contained within Bandelier National Monument. Access is exclusively by shuttle bus from the transfer station at White Rock, except during the winter months or if you have a handicapped parking permit, or if you intend to camp on site. The transfer station has extensive parking and a modest number of inexpensive overnight trailer stations, and it ties into the main bus system of Los Alamos County, which does not charge fares. A 7-day individual pass to Bandelier is $6.

The main attractions at Bandelier are the extensive archaeological sites, but there is also some splendid geology, especially in the back country. For a short visit, I recommend the hike to Upper Falls. If you have more time, the hike from Ponderosa Campground the length of Frijoles Canyon to Upper Falls is a nice tour of many of the formations of the Pajarito Plateau.

Kashe-Katuwe National Monument

The tent rocks of Kashe-Katuwe National Monument and the Veterans Memorial Overlook into the Bearhead Peak area are not to be missed. Hours are somewhat variable; I recommend arriving early in the day. Admittance is $5 per vehicle. Be aware that there is no lodging nearer than Santa Fe.

The road to the tent rocks is a paved all-weather road, but the road from there to the overlook is a gravel road which, while suitable for passenger vehicles in good weather, is closed during inclement weather or conditions of limited visibility.

No rock collecting is permitted within the boundaries of the Preserve or the National Monuments. Pets, other than service animals, may also be restricted to certain areas.

If you are planning to visit a number of the national parks, preserves, and monuments in the western United States during your trip, you may find it worthwhile to get an interagency annual pass. This is $85 per individual but gets you practically unlimited access to national parks, preserves, and monuments for a full year. Note that you will still need a back country permit in the Valles preserve (though there will be no fee.)

Santa Fe National Forest

Much of the Jemez surrounding the Valles preserve is under the jurisdiction of the Santa Fe National Forest. Unless there are local regulations to the contrary (as in the immediate area of Soda Dam) you may collect reasonable quantities of hand specimens for personal study.

Most roads are gravel roads and these vary greatly in quality. The best are suitable for all passenger vehicles in good weather; the worst are barely suitable for an off-road vehicle with high ground clearance and a roll bar. Take care on sharp turns on steep grades; even the roll bar won't save you if you go off a vertical cliff 50 meters high, of which there are many in the area.

Note that many of the forest roads are closed to most traffic from January 1 through April 15.

I offer descriptions of the more passable roads based on conditions during my most recent visits. Road conditions can change from year to year and even from month to month. Travel at your own risk.

Forest Road 289 (Dome Road)

This is the main road into the southeast Jemez and San Miguel Mountains. It branches off State Road Four, throws out a spur to St. Peter's Dome, and continues to the Cochiti area. The section from State Road Four to the Dome spur is a first-rate gravel road suitable for passenger vehicles in good weather. From there the road gets rougher, but is still acceptable for passenger vehicles driven with care, until you reach Cerro Balitas. Here the quality of the road becomes quite poor, so that I cannot recommend it except as a jeep trail. The road is presently (2021) closed at the boundary of Cochiti Pueblo, and in any case has been completely washed out by flash floods at the former Dixon apple orchard.

The spur to St. Peter's Dome is quite rocky but acceptable for passenger vehicles driven with care. Take particular care on the final ascent, and beware of an enormous pothole halfway along the road that can be crossed in dry weather but turns into a mud pool in wet weather.

Large pothole along Dome
        Lookout Spur
El Pothole Grande. 35.771483N 106.4066607W

Forest Road 36

This road also branches off State Road Four, with a branch that connects to Forest Road 289 and another branch that enters a lightly built up area near a volunteer fire station. There are several branches from here, all leading to private property. However, the road is another well-maintained gravel road suitable for passenger vehicles in good weather, and the area is scenic.

State Road 290/Forest Road 10

This is the main road through the southern Jemez, branching off State Road Four and passing though the village of Ponderosa before rejoining State Road Four.  The southern portion (SR 290) is a paved all-weather road, while the northern portion (FR 10) is a well maintained gravel road and quite suitable for passenger vehicles in good weather. This is a particularly scenic drive through a heavily forested area that has not experienced recent fires.

Forest Road 266

This road branches off Forest Road 10 onto Borrego Mesa and takes you to the Bear Springs area. It is not as good a road as Forest Road 10, but is negotiable in a passenger vehicle with reasonable ground clearance (such as an XUV) in good weather. The chief hazard is taking a branch of the road by mistake and ending up in a rock garden. Familiarizing yourself with the route and employing a GPS to navigate is recommended.

State Road 485/Forest Road 376

This is the main road in the southwest Jemez, paved from its junction with State Road Four to the Guadalupe Box and an excellent gravel road from there to its junction with State Road 126. The road is suitable for almost any vehicle in good weather, including campers, and goes through some of the most scenic country in the Jemez. If you have time for only one back country drive during your visit, this is the one I'd recommend.

Note that Forest Road 376 continues north of State Road 126. This portion of the road is rocky in places and badly washed out in others, but I have driven it in my Hyundai Santa Fe.

State Road 126

This is the main road of the western Jemez. Though marked on maps as a highway, this road is only partially paved, being well-maintained gravel over its middle third.

Forest Road 100

This is the main road in the northern Jemez. It branches off State Road 96 at Youngsville and continues high into the Jemez, where it eventually joins up with Thirtyone Mile Road (Forest Road 144) via Forest Road 99. There is a spur to Encino Point and its magnificent overlooks. The road is another well-maintained gravel road, passable to campers at least to the La Grulla Plateau. The Encino Point turnoff could be awkward for large vehicles, and the road is gated a significant distance from the old fire tower. The best lookout point is directly west of the gate at the end of the long meadow.

Forest Road 144 (Thirtyone Mile Road)

This road departs from Espanola and runs into the northwest Jemez to join State Road 126. The road is well-maintained gravel at least as far as the foot of Gallina Mesa. From there the road becomes quite rocky as it climbs towards the rim of the Valles Caldera, but it is negotiable for passenger vehicles in good weather with careful driving. There are logging roads up onto the rim itself -- a magnificent view -- but these are in quite poor shape and are best driven (if at all; the hike is not far) in a four-wheel drive vehicle with good ground clearance.


There are no unusual hazards in the Jemez area. Nevertheless, you can certainly get yourself killed here if you work at it a little.


The Jemez experiences a summer monsoon from early July to late September that can cause torrential if brief rain from local thunderstorms, mostly in the afternoon. Lightning danger is very high. If you hear thunder, get off high ground as quickly as you safely can. If you are caught in the open, stay away from isolated trees or other natural lightning rods, and crouch low on your feet. Rubber soles provide modest protection by acting as an insulator. Don't head for stream beds, as there is danger from ...

Flash flooding

Warning sign

The Jemez are crossed by numerous deep and narrow canyons and arroyos (dry stream beds). A sudden cloudburst can fill these with roaring water with amazing speed. Do not hike in arroyo bottoms if there is another route; do not hike in arroyo bottoms if there is any sign of rain; and if you do insist on hiking in an arroyo bottom, be ever mindful of the fastest route to higher ground in case the need arises. 

Water and sunshine

The Jemez covers three climate zones, from the high desert of the Upper Sonoran Zone below 2100 meters (7000') through the Transitional Zone between 2100 meters and 2700 meters (9000') to the Canadian above 2700 meters. The Upper Sonoran is characterized by piñon and juniper scrub forest and arid grassland; the Transition Zone by ponderosa forest; and the Canadian Zone by mixed forest of spruce, fir, and aspen.

Taking adequate water when hiking is a must. You require a full gallon of water a day when hiking in the lower terrain in mid-summer. The altitude also makes for wicked sunburns; you are well advised to slather on sunscreen rated SPF-30 or better regardless of how well tanned you already are. Insect life is locally abundant, so bring the DEET as well.

You are well advised to bring warm clothing even in summer if you are planning to hike in the higher elevations. If you are soaked by a sudden thunderstorm while on the trail, there is risk of hypothermia.

Cell phone coverage is limited away from the main settlements and paved roads. In an emergency, you may have a better chance of getting a connection if you are on higher ground, though there is no guarantee. You can pretty much count on no wireless service in the wild canyons of the north, west, and south Jemez. If you plan to hike in the back country, you may wish to bring a satellite GPS messenger.


Beware this critter.

Crotalus atrox
Crotalus atrox near the Veteran's Memorial Scenic Overlook. 35 40.138N 106 26.984W 

Crotalus atrox
Crotalus atrox in the Dome Wilderness. Near 35.7596596N 106.3471191W

This is the Western diamond rattlesnake, which, along with the prairie rattlesnake (Crotalus viridis), is the chief poisonous serpent of the Jemez area. Rattlesnakes are not uncommon and their bite is dangerous. I encountered the one in the first photograph at the overlook at Kashe-Katuwe Tent Rocks National Monument. I came within about a half second of stepping on the second while bushwacking in the Dome Wilderness east of the San Miguel Mountains. I've also encountered a rattlesnake next to the main loop trail at Bandelier National Monument.

Fortunately, rattlesnakes are not aggressive. They rattle because they would rather not tangle with you, and they are not looking for reasons to bite. Back away and you will be fine. The greatest danger is of stepping on an unnoticed rattlesnake while hiking rugged country, or of placing your hand on an unseen rattlesnake while scrambling over steep ground. Hikers in rattlesnake country must keep alert and always watch where they are stepping. Sturdy high-top hiking boots and loose-fitting long pants offer significant protection and should be considered standard hiking gear in the high desert.

Provoke an attack, and you had better hope someone in your group has the presence of mind to bundle you in a car and get you to a hospital for antivenom treatment as quickly as possible. Don't bother mucking around with trying to suck the venom from the wound or applying a constriction band; both are dangerous wastes of time when the right course of action is to keep the victim quiet, keep the bitten limb as low and as motionless as possible, and get the victim to a hospital as quickly as possible. If you can get a wireless connection, dial 911 for rescue, or use the SOS button on your satellite messenger.

The bull snake is a smaller animal that superficially resembles the Western diamond rattlesnake.


It can be distinguished by the lack of a rattler and the narrower shape of the head. The bull snake is harmless, but it never hurts to be on your best manners when encountering wild animals.

The only other poisonous critters of any significance in the Jemez are insects, spiders, and scorpions. None have dangerous bites or stings, but they can be very painful.


Tarantula in Dome Wilderness.

Tarantulas are not especially common most of the year, but during the months of August through October the males actively search for mates, often in large numbers. The spiders do not move quickly and are largely oblivious to the presence of humans.

The chief large predators are coyotes, bears, and cougars.


Coyote or timber wolf print in Valle Jaramillo.

Coyotes (smaller relatives of wolves) are not particularly dangerous unless infected with rabies. If a coyote acts oddly (and unprovoked aggression by a coyote is definitely odd) avoid the animal. If you get bit, you're in for a series of painful rabies vaccinations, with the added delight of a slight risk of the vaccinations failing, which means a most unpleasant death.

Bears are usually shy, rarely have rabies, and will normally attack only if cornered or if you come between them and their cubs. Do not offer food to bears under any circumstances. Do not leave food around your camp where it is accessible to bears. I once had the bad fortune to encounter a bear in the foothills of the Sierra de los Valles just as a four-wheel vehicle was approaching from the other direction; had the bear felt trapped between us, the situation could have got very ugly. Fortunately the bear had nearby brush to escape into. In the summer of 2015, another hiker was less lucky; he found himself between a bear and her cub and was badly mauled. A cross-country runner was mauled in the summer of 2016 when she inadvertently got between a mother bear and her cubs.

While bears account for a greater number of recent maulings than any other (nondomestic) species in the Jemez, cougars (mountain lions) are individually the more dangerous predator.

Cougar tracks

Cougar tracks near Clara Peak.

Fortunately, cougars are uncommon and wary of adult humans. I encountered one at a very uncomfortably close range in the outskirts of White Rock once at twilight. I kept my flashlight facing the cougar's glowing eyes while I slowly backed away about a hundred yards, then turned and ran like hell. It seemed to work. I am careful to keep a light on when walking in twilight now, so that any large predator will have warning that I am coming, and will likely quietly slip away. If you do encounter a cougar, look big, act noisy, and do not run until you are a good distance away; if you run at once, the cougar may decide you are prey and run you down.

Bobcats are also found in the Jemez area.

Bobcat prints?

Possible bobcat prints in Red Wash Canyon.

While they occasionally take down a deer, attacks by non-rabid bobcats on humans are quite rare. Bobcats are most active in twilight. The photograph here shows prints which, based on their size and the lack of any visible claw marks, are likely from a bobcat.

Some wild animals are very comfortable indeed around humans.

Bobcat prints?

Grey fox on my back porch

This is a gray fox, Urocyon cinereoargenteus. This particular animal has wintered two years now on our back deck. We leave it completely alone, but find its choice of our deck for its winter naps rather flattering. The species is known to favor human-inhabited areas because we frighten off its main predators. Supposedly, the species is able to climb trees; the wooden deck, painted just the right color, must be very inviting.

Raccoons are occasionally encountered in the Jemez region, and are notorious garden pests in settled areas.


Racoon prints in the Dome Wilderness.

I once had a tent torn open by a hungry raccoon looking for treats in northeastern New Mexico. The raccoon discovered a plastic baggie full of Benadryl, which it mistook for candy. I don't think the Benadryl agreed with the poor creature. The lesson is that even items you do not normally think of as food may attract wild animals.

Elk are the largest herbivore commonly found in the Jemez.

Elk stag in the fog at Valle Grande

They are normally shy, but if you provoke a stag elk like the one in this photograph, he's going to get mean. While there have been no recent gorings by elk in the Jemez, it is wise to give these animals some space. You can often hear nearby elk bugling, particularly during the autumn mating season.

Sound of elk bugling

The most common large herbivore in the Jemez is the mule deer. They are routinely spotted near highways throughout the region.

Mule deer

Most of those encountered are somewhat acclimatized to humans but, like all wild animals, should be respected.

Prairie dogs are numerous around the Valles Preserve headquarters. Their only danger to humans is as carriers of of flea-borne diseases. I mention them only because they are so darned cute.

Prairie dog near Valles
          Preserve headquarters

Notwithstanding the common name, prairie dogs are rodents of the squirrel family rather than canids. The one seen here is likely the Gunnison prairie dog, Cynomys gunnisoni. Though rarely of direct concern to humans, prairie dog dens are a hazard to cattle, which can break a leg if it is caught in a den opening. Since many of their predators are driven out of farm country, the populations can become quite large. The colony around the Valles headquarters is enormous, likely because predators are wary of the high human traffic in the area. The prairie dogs here seem so sleek and fat they can barely waddle.

Volcanic Activity

I suppose this one has to be included, if only to reassure the nervous reader.

Hydrothermal activity suggests that the Jemez volcanic field is still capable of activity. There is little seismic activity in the caldera, suggesting that the rocks beneath are hot enough that the brittle to ductile transition takes place at a relatively shallow depth. Seismic waves passing beneath the caldera from earthquakes nearby are attenuated in a way that shows the presence of molten rock. Careful analysis of seismic data suggests that there is a lens-shaped zone centered beneath the caldera that is 17 km (10.5 miles) across, centered at a depth of about 11 km (7 miles), and at least 8 km (5 miles) thick, composed of a sludge of partially crystallized magma. Careful measurements of the Earth's electric and magnetic field around the caldera (magnetotelluric measurements) also suggest a magma body at depth.

However, there has not been any volcanic activity in the Jemez for 74,000 years; and, while it is quite likely there will be further eruptions someday, the odds are heavily against one in our lifetime.

There would be warning signs of such an eruption. One of most reliable indications of rising magma is an increase of sulfur emissions from hot springs and fumaroles, which can begin years before the actual eruption. The caldera is regularly monitored by synthetic aperture radar (SAR) satellites that would likely detect the ground surface rising due to injection of magma into the magma chamber. As magma begins moving towards the surface, it fractures the rock along its path and produces a characteristic kind of earthquake called harmonic tremor. Since the Jemez is monitored by the Los Alamos Seismic Network, established in 1973, harmonic tremor would likely be detected almost at once. Finally, almost every violent volcanic eruption on record has been preceded by at least a few hours of ash eruptions that typically pose little immediate danger. Were such warning signs to appear, the sparsely-populated Jemez could be evacuated within a very short time.

Geological History Animations

The previous chapters have discussed the story of the Jemez, from the birth of Northern New Mexico 1.8 billion years ago to the deposition of alluvium in the modern stream drainages. The following animations depict this history.

The first animation shows the exposure maps you've seen throughout the preceding chapters as an animation.

Animation of exposures by age

The next animation is similar, but is cumulative in time, adding successively younger exposures.

Cumulative animation of Jemez exposures

I find these useful for visualizing the slow growth of the rock record in the Jemez over the ages.


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