Few substances are as maligned as dirt. If we’re dirt poor, our only option is to get things dirt cheap. We can treat someone like dirt, which may include digging up dirt on them. We take off our shoes, so we don’t drag dirt into the house. We let dirty dishes soak in the sink. And we throw dirty clothes in the washer. Just don’t air your dirty laundry in public, because that’s a big no-no.
But in Chimayó, New Mexico, the dirt is holy—and after my mother’s death at the age of ninety, the thought of visiting this healing shrine, famed for its sacred soil, came out of nowhere and wouldn’t let me go. Perhaps it was tied to the fact my mom had been an Iowa farmer’s wife and so, in the paradoxical logic of the spiritual realm, Chimayó would be the perfect place to say goodbye to her. Or maybe it was simply that I needed healing, now that I was an orphan. A middle-aged one, to be sure, but an orphan nevertheless.
On the weekend before I flew to New Mexico, a funeral director handed me a box that contained her earthly remains. “Here’s Mom,” he said with incongruous good cheer.
I took the box, gingerly, and wondered what I would do with it. I considered taking some ashes with me to Chimayó, following the example of friends who’d scattered the remains of loved ones in beautiful sites around the world. But my mother had disliked traveling when she was alive, and I guessed that her thoughts on the matter probably hadn’t changed after her death.
Then I considered the mantelpiece in my living room, but it didn’t seem right to display her ashes in public. Storing the box in the basement felt disrespectful, and I definitely didn’t want it in my bedroom. So finally I settled on my office, a little upstairs room that once was a walk-in closet. I put the box of cremains next to a statue of the Virgin Mary, then draped a scarf over both Mary and the box so that it looked like it was tucked under her arm. I would glance at it occasionally as I worked, wondering when I’d have the courage to open its lid and look inside.
Long before the Spaniards arrived in the region, Chimayó was considered holy by the Pueblo people, who thought that healing spirits inhabited the hot springs in the area. After the springs dried up, people came for the dirt where the water had once been. The miracles, apparently, didn’t mind whether they came through water or soil.
Chimayó’s fame spread to the larger world around the year 1810, when a story began to circulate of a local man, Bernardo Abeyta, who saw a light springing from one of the hills near the Santa Cruz River. After following the light to its source, he found in the earth a crucifix bearing a dark-skinned Jesus. The local villagers paid homage to the relic and then took it to a church in nearby Santa Cruz. Mysteriously, during the night the crucifix returned to its original location. After this happened two more times, the locals received permission to build a small chapel to house the crucifix in Chimayó.
Our Lord of Esquipulas, as the figure on the crucifix is known, is also linked to a shrine in Guatemala that has been associated with healing earth. Franciscan friars helped spread devotion to this icon throughout Mexico and New Mexico. It must have seemed natural to them to link the Pueblo people’s stories about the site’s healing earth to the Catholic devotion to Our Lord of Esquipulas.
And so through the years, the story of the crucifix became intertwined with Indigenous beliefs. It became part of a story that’s been repeated countless times throughout history: the stones from pagan temples get reused for churches; cathedrals are built over earlier sacred sites; churches whose congregations have dwindled become houses of worship for other faiths. The Holy Spirit seems to love recycling as much as environmentalists.
Humble Chimayó’s reputation for miracles gradually spread, drawing an increasing number of pilgrims to the simple adobe church whose official name is El Santuario de Chimayó. After World War II, survivors of the Bataan Death March made a walking pilgrimage to the church on Good Friday in gratitude for their deliverance. The tradition of Holy Week pilgrimages continues to this day, when more than thirty thousand people walk to the church before Easter. Many travel the eight miles from the town of Nambé, while others walk from as far away as Santa Fe or Albuquerque.
My own pilgrimage began with a flight to Albuquerque in the low season of February, followed by a two-hour drive north, first on a broad highway and then on narrower roads that led me into brown hills of sparse grass and scattered junipers. At last, I reached Chimayó, a village of about three thousand in the foothills of the Sangre de Cristo Mountains. When I pulled into the parking lot at the shrine there were only two or three other cars there. The wind was chilly as I walked past deserted outdoor shrines to the Virgin Mary and alcoves holding statues of saints. It all looked a little forlorn, like a party room after the celebration is over.
But once I entered the church, I found it as warm and inviting as I remembered from my previous two visits. The adobe church with twin bell towers is one of the finest examples of Spanish Colonial architecture in New Mexico, with a timbered ceiling, rough-plastered interior walls, and simple wooden pews. Five reredos of colorful folk art adorn its walls, one behind the altar and two on each side of the nave. A six-foot crucifix hangs above the altar, a cross that’s said to be the same one found by Bernardo Abeyta.
On my previous visit, a priest gave a homily full of good humor and humanity to a church in which every pew was filled. Many of the people had seemed like locals, but I had also heard Japanese and French on my way out. Today, the church was empty, though a stand with flickering candles near the altar showed that other pilgrims had been there before me.
I sat for some time in that simple sanctuary, grateful to be at my destination and pondering what had drawn me here. I wasn’t seeking a miracle, unlike many who come here. My mother had lived a good and long life, and amid my sadness, I felt relief that her twilight journey through dementia was now over. But I also sensed a fissure inside me, a recognition that some primal link had been broken. I was trying to find my bearings as I learned to live the rest of my life without either parent. My eye was caught by a wooden bust of the Virgin Mary that looked down on me from a window sill above, and I felt grateful to have her maternal gaze rest on me.
I stood up, walked past the altar, and exited the church to the adjoining small room known as the pocito, which in Spanish means “little well.” By tradition, this is the spot where Abeyta found the crucifix in 1810. Bowing my head at the low entryway, I saw the small hole in the ground that I remembered from my previous visits. About a foot in diameter, it’s filled with fine-grained dirt. This is the spot where thousands have knelt, ladling handfuls of powdery soil into containers they brought from home. I crouched down to pick up my own handful of dust, feeling its coolness sift through my fingers, thinking about the fact that I’d been to many shrines with holy water, but never one with holy dirt.
In a 2008 interview, Father Casimiro Roca, who served as rector at the church for more than five decades, said that the dirt is replenished each day by human hands, not miraculously replenished as some believed. “I always tell people that I have no faith in the dirt, I have faith in the Lord,” he told a New York Times reporter. “But people can believe what they want.”1
Stepping into the room adjacent to the pocito gave ample evidence of the piety of those who come here seeking healing. A row of crutches hung on one wall, presumably left by those who no longer needed them, and photographs lined the walls testifying mutely to the prayers that have been said here. I stood for a long time looking at the faces of those in the photos: soldiers in uniform, elderly women in hospital beds, fresh-faced school children, tattooed motorcycle riders, babies with oxygen tubes. I spotted one that looked like my mom, an elderly woman with a kind smile. Blinking back tears, I pulled my jacket closer in the chilly room and then left the church.
The Beauty of Bones
Georgia O’Keeffe went searching for flowers, but instead she found bones.
The famed artist was on my mind as I set out from Chimayó for an afternoon of exploring. Her iconic images of whitened animal skulls, multicolored cliffs and canyons, and high desert vistas are indelibly linked to the region surrounding Ghost Ranch, which lies an hour north of Chimayó. I was longing to see for myself those stark panoramas so different from the tidy farms and hills of my native Iowa, wanting an outer landscape that matched my inner mood.
O’Keeffe became fascinated by New Mexico on a visit to Santa Fe in 1917 when she was twenty-nine years old. “From then on, I was always on my way back,” she later said. For a number of years, that meant summer visits from her home in New York, but in 1949, she moved permanently to the region, first to a house at Ghost Ranch and later to one in the small village of Abiquiú.2
For years O’Keeffe’s life was overshadowed professionally and personally by her husband, the photographer Alfred Stieglitz. In 1933, she experienced a crisis caused by his infidelities, though the two remained married until his death in 1946. Their marital difficulties accelerated her need to redefine herself in the starkness of the New Mexico desert. There, she found new directions in her art and an inner strength that sustained her for a future that would be largely solitary. Keenly attuned to the power of nature, she sought out the strangeness hidden in the familiar, removing what was nonessential by emphasizing color and shape. The dramatic, stripped-down countryside of northern New Mexico became her artistic and spiritual home.
Before O’Keeffe fell under the spell of New Mexico, many of her paintings had featured lush flowers. But because blooms are sorely lacking in the high desert, here she turned instead to collecting and painting bones from animals whose carcasses had been picked clean by scavengers and then bleached by the sun. “To me, [bones] are as beautiful as anything I know,” she said. “To me they are strangely more living than the animals walking around. . . . The bones seem to cut sharply to the center of something that is keenly alive on the desert even though it is vast and empty and untouchable.”3
O’Keeffe loved the angles and shapes of the bones and was fascinated by the ways they could be used to frame and dramatize the landscape. Some of her best-known paintings show skulls she’d collected on her walks through the desert. Some may see these works as meditations on mortality, but for her the bones were more symbols of endurance and strength than symbols of death. Bones show the underlying structure of an animal, the reality hidden underneath its surface, and in her work, they also hint that deeper meanings are hidden within the New Mexico landscape.
As I drove through a landscape of red cliffs and canyons near Ghost Ranch, I saw many scenes that were familiar to me from O’Keeffe’s work. The mountain known as Pedernal loomed in the distance, its peak sacred to the Navajo and Jicarilla people and one that O’Keeffe painted many times. She said she thought that if she painted it often enough, God would give it to her, though in the end the opposite became true: after her death, her ashes—which were actually pulverized bones, like all cremains—were scattered there, so that she became part of the mountain.4
I could see why O’Keeffe felt so at home in this wild and open countryside, a landscape perfectly suited to her need for solitude. I felt myself craving to be alone here. Normally, I seek out conversations when on trips, eager to learn about a place from a local’s perspective. On this journey, my impulse was just the opposite. As O’Keeffe had realized before me, this is a good place to be alone.
I remembered the visit I’d made on my previous visit to O’Keeffe’s home and studio in the small village of Abiquiú. She’d purchased a rundown house there in 1945, and after restoring it, she made it her home for all but the last two years of her life. On my tour, I was amused by the docent’s reverent attitude toward the artist and her military-style enforcement of security measures, including forcing us to relinquish all the pens and pencils we had in our bags, as if we were likely to start drawing on the walls like kindergarteners. But as I listened to the story of O’Keeffe’s life there and her almost-religious devotion to her art, I could see why she has become a kind of secular saint in this part of the world. Like the desert hermits of the third century in Egypt, she was cantankerous and odd, which I guess are good traits to have if you’re seeking meaning in a desert.
I pulled into the long drive leading to Ghost Ranch, which is now a spiritual retreat center that attracts visitors from around the world. A cold wind had sprung up and a light dusting of snow covered the red, yellow, and gray badlands. I walked the paths between rustic wooden buildings, thinking of the many pilgrims who find their way here each year. As I meandered, I thought of one of my favorite O’Keeffe paintings, From the Faraway, Nearby, which shows an antlered skull floating in the sky above a desert landscape.
At first it looks like an ordinary skull, but then one realizes it has a mythic quality, with far too many points on its antlers to represent any real animal. I love the painting’s juxtaposition of the familiar and the dreamlike, the near and the distant. Its mood evokes something related to what I was searching for: a deeper perspective on life, one that’s comfortable with paradox, that’s rooted in a sacred landscape, and that only appears ordinary at first glance.
On the drive back to Chimayó I could see Pedernal in the distance, and I thought about O’Keeffe’s ashes, gradually being incorporated into the mountain she loved, and my mom’s ashes, tucked beneath Mary’s arm in my office.
The Treasure Beneath Our Feet
Amid the array of ordinary substances made sacred in Christian rituals, dirt takes a back seat to bread, wine, and water. The major exception is Ash Wednesday, when many denominations hold services that include the imposition of ashes, which is a fancy way of saying that they smear dirt on people’s foreheads. Traditionally, the black soot is created by burning the leftover palms from the previous year’s Palm Sunday service; it thus serves as a reminder of the cyclical nature of life, the way our shouts of praise and hosanna inevitably fade, and our green branches become brittle. When the soot is pressed into service on Ash Wednesday, it reminds us that we’re going to die. Too often in the religious world we sugarcoat reality but not on this day. From dust we came, and to dust we will return.
Yet my time in Chimayó made me realize that the Christian understanding of dirt is more multifaceted than that. Sure, there are plenty of Bible verses that speak negatively of dirt, and I’ve known more than a few altar guild members with an evangelical zeal for removing it. But Christianity actually has a pretty good relationship with dirt, starting with the fact that in the Genesis creation story, which parallels many other stories from traditions around the globe, God creates the first humans from soil. The word humus, a synonym for soil, shares the same Latin root as human and humanity. These words are also related to humility, which is just what we’re supposed to feel when the smudges of ashes on our forehead disintegrate into tiny black speckles on our noses, cheeks, and chins.
In the Gospels, a story that makes neat freaks uncomfortable is when Jesus spits into the dust, forms a paste, and puts it on the eyes of a blind man. Go wash it off, he tells the blind man, and when the man obeys, his eyesight is restored. Whatever Jesus was up to—and it’s obvious that despite his divinity, he should never be put in charge of sterilization protocols in a hospital—it’s obvious that he wasn’t afraid of a little dirt.
One example of someone who loved working in the dirt is Saint Phocas, the patron saint of gardeners. During the third century when the Roman Empire was persecuting Christians, this kind man grew food for the poor. One day, a group of soldiers knocked on his door, asking for directions to the house of a Christian named Phocas, whom they were to arrest and execute. He cordially invited them in, offered them food, and put them up overnight. In between his hospitality duties, he went out into his garden and dug a man-sized hole in its rich loam. The next morning, he told the soldiers that he was the person they were looking for, then asked them if they would they be so kind as to kill him next to the grave he’d dug so that his body could fertilize the garden.
The story of Phocas underscores the fact that death is intricately tied to soil, which is the greatest recycler on earth. Without its regenerative power, the corpses of once-living things would overwhelm us. Instead, the soil’s microbes, fungi and invertebrates take what is given to them and return the nutrients and carbon back into forms in which they can be used again. Thus, we are all recycled plant and animal material, the culmination of many trillions of lives, large and small.
To learn more about what science can tell us about dirt, I turned to my friend Art Bettis, a geologist who specializes in soils. The first thing he did was set me straight on terminology. “Dirt is the stuff you get on your shoes,” he said. “Soil is a living substance that sustains all terrestrial life. It’s the most valuable—and the most unknown—ecosystem that we have. And it’s full of information about the past, both the recent past and the distant past.”
My crash course in soil science from Art gave me a much greater respect for the element I’d formerly ignored. The thin layer of soil on the outside of the earth—just 7 percent of the surface of the planet—has been formed over millions of years from the weathering of rocks into mineral particles that gradually become mixed with organic matter, air, water, and living organisms. In wet tropical climates, it takes about two hundred years to form one centimeter of soil; in milder climates it can take twice as long—and to create truly rich, fertile soil takes several thousand years.
Once it’s formed, that fertile topsoil is a miraculous wellspring of life. In addition to growing plants, it acts as a kind of lung, releasing and absorbing water vapor, carbon dioxide, and other gases. Billions of species dwell within soil, from moles and fungi to bacteria—in fact, just a single handful of soil contains more organisms than the entire human population of the earth.
Art opened my eyes as well to the tremendous diversity of soils across the globe. Scientists divide them into twelve orders, though those classifications are in a continual state of flux as research reveals more information. I was pleased to learn that states have official soils, just as they do state birds. Connecticut has the regal Windsor; North Carolina, the bow-tied Cecil; and Minnesota, the next-door-neighbor Lester. Less amusing, but more authentic to the Indigenous origins of the regions, are Idaho’s Threebear and Rhode Island’s Narragansett.5
I don’t mean to brag, but my own state of Iowa’s official soil, Tama silt loam, is some of the best in the world, at least if you’re trying to grow things. It has an intense, dark color and is teeming with nutrients, microbes, and animals from earthworms to mites. And according to Art, it didn’t even exist eleven thousand years ago. “Tama Silt Loam began its evolution as a thin soil in Iowa’s late glacial evergreen forest, then became thicker, but still organic poor as the vegetation shifted to deciduous forest,” he said. “During the past six thousand years it became much richer after all the organic material of the tallgrass prairie ecosystem became incorporated into it. When it was first plowed, the prairie’s topsoil was more than three feet deep in Iowa.”
Art’s words emphasize the dynamic nature of soil. Its composition changes depending upon factors like rainfall quantity, what’s decaying on top of it, and what’s living in it. Despite being a substance with no legs or wings, it also has a surprising ability to move. It’s estimated that twelve million tons of dust from the Sahara drop onto the Amazonian rainforest each year, for example, where its minerals help replenish rainwater-depleted soils. Other soil movement is much more negative, including the many tons of fertile topsoil that get washed away every year in the Midwest. While the thick roots of prairie plants once held Midwestern soil in place, modern farming practices too often lead to significant erosion, and as a result, that thick layer of topsoil that existed when the pioneers first came to the Midwest has been reduced by more than half. Given how long it takes to regenerate soil, that’s an unsustainable phenomenon.
Of course, agriculture is just one of the ways in which soil benefits humans. Many of our most important medicines come from the soil, including more than five hundred types of antibiotics. Conversely, health researchers speculate that our rising rates of allergies and asthma may be linked to too much cleanliness. One piece of evidence is that children raised on farms have lower rates of these medical issues.6 As a farmer’s daughter who ate more than her fair share of dirt while growing up, I suspect that my immune system benefited from the many workouts I gave it.
Although I appreciate my crash course in soil science from Art, I don’t want to give up on that homely word dirt. Like many short English words that derive from Old Norse, from sky and lake to bug, it retains a Viking earthiness—in fact, its original form of drit means excrement. Because manure makes great fertilizer, that’s not necessarily an insult. For thousands of years the main fertilizer on farms was manure, which adds nitrogen, phosphorus, and potassium to the soil. It was so valuable that in Europe young women’s dowries were sometimes calculated according to how much manure was produced on their childhood farms.
And what would it mean if we viewed dirt not only as valuable, but also as holy—not just at Chimayó but everywhere? If we took that kind of a perspective, we’d be much less likely to let it wash off our fields and into rivers, like foolish spendthrifts who throw their money away without a care. Instead, we’d be like Saint Phocas, deeply conscious of our need to nourish and protect it. I think, too, of the people of Effigy Mounds near my home in Iowa, who hundreds of years ago carried countless baskets of earth to form ceremonial mounds on the top of bluffs overlooking the Mississippi River. I suspect they had a sense for the preciousness of what they were carrying.
All of which reminds me of a joke. A group of scientists form a delegation to meet with God. “There’s no need for a divine being any more,” they say, “given all we know about science. We can clone animals and manipulate genes to create living creatures faster and better than you can.” So God challenges them to a human-making contest, which they eagerly accept. After he invites them to go first, one of the scientists reaches down to scoop up a handful of dirt, until God interrupts him.
“Oh, no,” God says. “You have to use your own dirt.”
I spent three days hanging around Chimayó, walking its meditation path near the Santa Cruz River, browsing the weaving shops for which the area is famous, and sitting quietly in the adobe church. Although about three hundred thousand people visit the area each year, my arrival in February meant that I had it largely to myself. Occasionally others would wander through, spending just a few minutes in the church before heading to the pocito, the room with the holy dirt. I watched the other visitors, trying to guess what they were praying for—recovery from illness, a pregnancy for a daughter, healing of a troubled marriage, comfort after receiving a terminal diagnosis? The flickering votive candles lit by pilgrims bore witness to their silent prayers.
I could see, too, the ways in which the shrine has ties to a variety of spiritual traditions. In its outdoor meditation gardens, for example, there’s a statue dedicated to Our Lady of La Vang, which draws pilgrims of Vietnamese and Filipino descent. Her story dates back to 1798, when a group of Catholics who were fleeing religious persecution hid in the forest of La Vang in Vietnam. While praying the rosary under a banyan tree, they saw a beautiful lady with an infant in her arms. She spoke words of comfort to them, promised to be with them, and directed them to gather leaves from nearby bushes to make a drink that would heal their illnesses. Mary appeared in the forest a number of times after this initial apparition, and La Vang became a famous holy site. At Chimayó, her statue has features that reflect her origin in Asia, which helped me see the many ways in which the holy is expressed here.
Nearby is a small chapel that reflects the Indigenous roots of the shrine. The word Chimayó comes from Tsi-Mayoh, which in the Tewa language refers to one of the four sacred hills that overlook the valley. The chapel’s iconography incorporates Native American images and symbols, from the altar’s candleholders, which are shaped like ears of corn, to a tableau of the Last Supper featuring Indians in the dress of various tribes.
I found it curious that the Native American traditions surrounding healing earth remain so strong here. I remembered Art telling me about the widespread practice of eating dirt in traditional cultures around the world, especially in areas where the soil provides essential minerals that are otherwise lacking in people’s diets. In past centuries, pilgrims ate the holy dirt here, too, though that practice has fallen out of favor. Instead, pilgrims are advised by the clergy to pray, confess their sins, and ask God for guidance and healing. If they like, they can then rub the blessed dirt over the parts of their bodies in need of healing, which isn’t that much weirder than a lot of medical folklore and would certainly help stimulate the placebo response, if nothing else. At some deep level, we seem to know that the earth has healing powers, if we just pay attention to what’s beneath our feet.
A block away from the shrine, I found another church that draws nearly as many visitors as the santuario: the Chapel of the Holy Child of Atocha, whose devotion has roots in a story from Spain. In the thirteenth century, some Christians were being held captive in the Madrid neighborhood of Atocha. To reduce the threat of escape, their captors would allow only children to deliver food and water to prisoners, but this meant that the prisoners who had no family were suffering greatly. One day, a young boy showed up with a basket of food and a gourd of water for the prisoners. The soldiers let him through, and the next day he returned again, and then again and again. His basket and gourd miraculously remained full, despite the many men who ate and drank from them. The prisoners took this as an answer to their prayers, believing that the child was Jesus. The Holy Child of Atocha, as he became known, became a figure of devotion throughout Spain and, later, Mexico.
In 1857, a resident of the Chimayó region, Severiano Medina, made a vow that if he recovered from his illness, he would make a pilgrimage of more than one thousand miles to a shrine in Zacatecas, Mexico, that is dedicated to the Holy Child of Atocha. After recovering and making the trek there and back, he built a chapel dedicated to this manifestation of the divine.
At the chapel, I learned why survivors of the Bataan Death March started making pilgrimages to Chimayó. After the bombing of Pearl Harbor, nearly two thousand members of the New Mexico National Guard fought valiantly with Filipino soldiers against the Japanese invasion of the Philippines. Defeated after seven months of battle, the soldiers were forced to walk sixty-five miles to POW camps, a brutal march during which many died of exhaustion, dehydration, starvation, and violence. Of the seventy-five thousand US and Filipino troops who began the march, an estimated ten thousand died along the way. The survivors spent forty months in a variety of POW prisons and slave labor camps, enduring harsh conditions that led to many more deaths. By the end of the war, only about half of the members of the New Mexico National Guard were still alive. Many attributed their survival to the Holy Child of Atocha, whom they believed watched over them in their time of dire need.
Sitting in the church dedicated to the Holy Child, I realized it would be easy to misinterpret its iconography, which in contrast to the more somber, rough-hewn mood of the santuario is much brighter and more modern, with an emphasis on the innocent Holy Child rather than the suffering Christ. But learning the story behind the Good Friday pilgrimage made me realize how the two churches are linked. Darkness and light, illness and healing, suffering and redemption are intertwined in both.
The World War II story also gave me new insights into the small statue of the Holy Child of Atocha that rests in a glass case behind the church’s altar. The young boy is sleeping, his head propped up against his hand. The faithful believe he’s dozing because each night he walks out from the church in search of those in need. Many pilgrims to this church leave small shoes as a gift because the Holy Child wears them out so quickly in his travels.
It’s not just pilgrims who walk in search of God, I realized as I sat in that quiet church. God walks in search of us as well.
A few weeks after returning from Chimayó, I attended an Ash Wednesday service at my church. A priest put a smudge of ash on my forehead and repeated the familiar words, “From dust you came, and to dust you will return.”
I walked back to my seat, sanctified by holy dirt.
- Erik Eckholm, “A Pastor Begs to Differ With Flock on Miracles,” New York Times, February 20, 2008, https://www.nytimes.com/2008/02/20/us/20dirt.htmlhttps://www.nytimes.com/2008/02/20/us/20dirt.html.
- O’Keefe quoted in Lesley Poling-Kempes, “A Call to Place,” in Georgia O’Keeffe and New Mexico: A Sense of Place, ed. Barbara Buhler Lynes, Lesley Poling-Kempes, and Frederick W. Turner (Princeton, NJ: Princeton University Press, 2004), 78.
- O’Keeffe quoted in “The Natural World,” Georgia O’Keeffe Museum, https://www.okeeffemuseum.org/installation/the-natural-world/.
- See “Pedernal Society,” Georgia O’Keeffe Museum, https://www.okeeffemuseum.org/support/pedernal-society/.
- See Natural Resources Conservation Service, “State Soils,” United States Department of Agriculture, https://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/edu/?cid=stelprdb1236841.
- Jocelyn Kaiser, “Dirty Farm Air May Ward off Asthma in Children,” Science, September 3, 2015, https://www.sciencemag.org/news/2015/09/dirty-farm-air-may-ward-asthma-children.