Category: Places

Tejon Pass is a Journey Through Time, Terrain, and Tectonics

Interstate 5 coming out of the Grapevine near Tejon Pass (Photo: Erik Olsen)
Support California Curated with a small donation.

There’s a drive that I’ve done many times where I tend to look around and wonder about the place. It’s while I’m on I-5 headed north, a while after passing Santa Clarita, Magic Mountain (I always strain to see if there are people on the roller coasters), and the CalArts up on the hill (where so many Pixar legends once trained).

Perhaps you’ve done it, too. Maybe you get gas in Castaic, then you pass Pyramid Lake, and you’ve fully left the San Fernando Valley behind. Then the climb begins and the terrain changes dramatically. It’s subtle at first. The road starts to rise, winding past low ridges covered in golden grass and sun-bleached rock. Then the grade steepens. You see warning signs for trucks: “Turn off A/C to avoid overheating.” Semis tuck into the right lanes, their flashers blinking, straining against gravity. You’re ascending into the Tehachapi Mountains. The name comes from the Southern Paiute word “Tihachipia” meaning “hard climb”, which makes a ton of sense when you’re there. These mountains are part of the geologically fascinating Transverse Ranges, which we’ve written about before. Up ahead is Tejon Pass, the official name for the mountain crossing, but it’s more famously known to most drivers as the Grapevine, the steep stretch of I-5 that descends into the Central Valley.

The highway carves through steep canyon walls and hillsides sometimes bright with flowers, sometimes scarred by past wildfires. If it’s summer, the air gets drier and hotter; in winter, it might be raining or even snowing. You’re crossing one of the most weather-vulnerable stretches of highway in the state. The road is wide but unforgiving. Watch for crosswinds, or the occasional patrol car tucked into a turnout. Tejon Pass is more than just a mountainous pathway connecting the San Joaquin Valley to Los Angeles. It’s a geological and historical hotspot that tells a story of native tribes, daring transportation, seismic activity, and human ingenuity.

The weather can change quickly near Tejon Pass (Photo: Erik Olsen)

Rising to an elevation of 4,160 feet, Tejon Pass’s unique topography is a fascinating blend of rugged mountains, deep canyons, and expansive plateaus. At the summit, the land briefly levels out. There’s a moment where the mountains give you a glimpse in both directions. Behind, the tangled ridges of Southern California. Ahead, a vast, hazy bowl: the southern end of the Central Valley. You pass the Fort Tejon Historical Park turnoff, and suddenly, you’re descending.

The road plunges down in a series of long, controlled curves. Runaway truck ramps cut into the hillside like scars. Then, like stepping through a door, you’re out of the mountains. Flatness stretches to the horizon. Orchards, oil derricks, and cattle fields mark your arrival in the valley. The air feels different. Denser, warmer. You’re in Kern County now, approaching the outskirts of Bakersfield, and the Grapevine is behind you. It’s as if you crossed an invisible line, a border between two Californias.

CALIFORNIA CURATED ART ON ETSY

Purchase stunning coffee mugs and art prints of California icons.
Check out our Etsy store.

One of the most relevant things about Tejon Pass today is its seismic significance. The region is situated at the intersection of two major fault lines: the San Andreas Fault and the Garlock Fault. This combination has made the area a hotspot for seismic activity and has resulted in a number of substantial earthquakes over the years.

Image of the Garlock Fault created with data from NASA’s Shuttle Radar Topography Mission (SRTM)

The most significant of these events occurred in 1857. Known as the Fort Tejon earthquake, it was an estimated magnitude 7.9 and ruptured more than 200 miles of the San Andreas Fault, shifting the land by up to 30 feet in seconds. Shaking may have lasted several minutes, but with few people living nearby, the damage and death toll were minor. Most seismologists believe this segment is locked, meaning it doesn’t release energy through small quakes but instead builds stress until it breaks in a single, massive event.

Today, that same stretch of fault has been largely quiet for more than 160 years. Studies of ancient quake layers suggest it ruptures on roughly a 140-year cycle, leading many scientists to believe stress is building toward another major event, AKA “The Big One”.

Long before European contact, Tejon Pass was a vital passageway for several Native American tribes, including the Chumash and Tataviam. The area around present-day Gorman, near the pass, was home to the Tataviam village of Kulshra’jek, which functioned as a significant trading crossroads for centuries. These Indigenous communities recognized the strategic importance of the pass, utilizing it for travel, trade, and communication across regions.

Tejon Pass near Grapevine, California, in 1868

With the arrival of European settlers, the pass continued to play a vital role in California’s development. It became one of the state’s oldest continuously used roadside rest stops, a title it still holds today. The pass has borne witness to the evolution of transportation, from horse-drawn carriages to modern highways.

However, not all the tales from Tejon Pass are picturesque. The area has earned the foreboding nickname “Dead Man’s Curve.” This name references a notoriously dangerous curve on the old Ridge Route, infamous for its high number of accidents. The treacherous curve became symbolic of the broader challenges of early automotive travel through the mountains, where both engineering and human limitations were tested.

A section of the 1915 Ridge Route in Lebec, California, known as “deadman’s curve,” was abandoned when the highway was improved over the Tejon Pass. photo by George Garrigues.

The Ridge Route, completed in 1915, was California’s first paved highway directly connecting the Los Angeles Basin with the San Joaquin Valley. Engineered to traverse the challenging terrain of the Sierra Pelona Mountains, it followed a winding path from Castaic to Gorman, culminating at Tejon Pass. This innovative route was a significant milestone in California’s transportation history, facilitating automobile travel between Southern and Central California. ​

A notable segment of this route is known as “The Grapevine,” located in the northern portion descending into the Central Valley. The name originates from the Spanish term “La Cañada de las Uvas,” meaning “The Canyon of the Grapes,” a reference to the wild grapevines that early Spanish explorers, including Don Pedro Fages in 1772, observed growing abundantly in the area.

Over time, the Ridge Route underwent several significant transformations to accommodate increasing traffic and improve safety. In 1933, it was replaced by a three-lane alternate highway, later designated as U.S. Route 99. This was expanded into a four-lane expressway by 1953 . Eventually, the route evolved into the modern eight-lane beast known as the Interstate 5 Freeway, completed in 1970, which continues to serve as a vital artery for transportation in California. You will encounter lots and lots of trucks. ​

Driving Tejon Pass and the Grapevine

Today, Tejon Pass continues to serve as a crucial thoroughfare for Californians and visitors alike, with Interstate 5 traversing the landscape. The Tejon Ranch Conservancy plays a central role in protecting and interpreting this remarkable landscape. Established as part of a landmark 2008 conservation agreement, the Conservancy is tasked with stewarding over 240,000 acres of permanently protected land—making it one of the largest private conservation efforts in California history. Its mission goes beyond preservation; the Conservancy offers guided hikes, wildlife tracking programs, and educational outreach that invite the public to engage directly with the land.

Superbloom near Tejon Ranch (Tejon Ranch Conservancy)

Soon, however, you leave Tejon Pass behind and continue north on I-5, dropping into the southern end of the Central Valley. You pass through the outskirts of Buttonwillow and Lost Hills, where the landscape flattens into a broad, arid plain. It’s mile after mile of industrial agriculture, just endless rows of almonds, pistachios, and oil wells under a hazy sky. The scenery turns monotonous, and although it does have a story (mostly about moving water), it’s one we’ll save for later.

Tejon Pass is one of those places most people barrel through without a second thought. It’s just a steep stretch of I-5 between Los Angeles and the Central Valley, a name on a weather report when the Grapevine closes in winter. But if you take a moment to look beyond the guardrails and gas stations, you’ll find a landscape layered with deep history and surprising complexity. Knowing what lies beneath the pavement won’t make the climb any less steep—but it might make the ride a little more meaningful.

Support California Curated with a small donation.

Hannes Keller’s Deadly 1,000-Foot Descent off Catalina Island Was the Dive of the Century

An ambitious quest for underwater exploration that ended in tragedy beneath the Pacific waves.

The city of Avalon on Catalina Island (Erik Olsen)
Support California Curated with a small donation.

In 1962, Swiss physicist and deep-sea diving pioneer Hannes Keller embarked on an ambitious and perilous mission to push the boundaries of human endurance and underwater exploration. California, with its dramatic coastline and history of daring maritime ventures, became the setting for this bold effort to make history in diving. Partnered with British diver and journalist Peter Small, Keller aimed to descend inside a specially designed diving bell named Atlantis to an unprecedented depth of 1,000 feet off the coast of Catalina Island. Their plan involved exiting the pressurized diving bell once it reached the ocean floor, a groundbreaking and dangerous procedure that would allow them to perform tasks outside in the extreme depths. What promised to be a historic achievement, however, took a tragic turn.

Keller’s passion for deep-sea diving had recently garnered international attention, fueled by his record-breaking dives and groundbreaking research into advanced breathing gas mixtures. Working alongside Dr. Albert Bühlmann, a renowned physiologist specializing in respiration, Keller employed cutting-edge technology, including an IBM computer, to meticulously design gas formulas that could counteract the dangers of deep diving. Their innovative work addressed the twin challenges of nitrogen narcosis and decompression sickness, promising to revolutionize underwater exploration.

For Keller, diving was initially an unconventional pursuit. He was engaged in teaching mathematics to engineering students in his native town of Winterthur, close to Zurich, and had aspirations to become a pilot. However, the prohibitive cost of flying on a teacher’s salary led him to explore other avenues. Introduced to the burgeoning sport of scuba diving by a friend in the late 1950s, Keller applied his mathematical and scientific acumen to the field. He soon concluded that the existing techniques in deep-sea diving were outdated and ripe for revolutionary advancement.

“If a man could go, for instance, to 1,000 feet down and do practical work,” Mr. Keller wrote in The Sydney Morning Herald, “then all the continental shelf zone could be explored, a total of more than 16 million square miles.”

Keller prepares for his May 1961 chamber dive at the United States Navy Experimental Diving Unit (NEDU). Photo: US Navy

Keller and Bühlmann worked collaboratively to expand their computerized concoction of breathing gases, ultimately selecting a dive site off near Avalon Bay at Catalina Island in Southern California. This location was chosen due to its dramatic underwater geography, where the ocean floor descends sharply from the coast into the deep ocean.

At the time, it was widely believed that no human being could safely dive to depths beyond three hundred feet. That was because, beginning at a depth of one hundred feet, a diver breathing normal air starts to lose his mind due to nitrogen narcosis.

Partnering with Peter Small, co-founder of the British Sub Aqua Club, Hannes Keller planned their historic descent using a specially designed diving bell named Atlantis. This advanced pressurized chamber, deployed from a surface support vessel, was staffed by a skilled technical crew tasked with monitoring gas levels and maintaining constant communication with the divers through a surface-to-bell phone link. The Atlantis diving bell represented a significant leap in underwater technology, providing a controlled environment that allowed divers to venture into previously unreachable depths. Its design and operational success revolutionized the field of deep-sea exploration, offering invaluable insights into human physiology under extreme pressure and laying the groundwork for future advancements in underwater science and technology.

Keller’s experimental dives piqued the interest of the U.S. Navy, as they saw the potential to revolutionize diving safety and practicality. If proven successful, Keller’s methods could transform existing dive tables and enable safer, more practical deep-sea exploration. Encouraged by the promising outcomes of Keller’s preliminary chamber tests and several less extreme open-sea trials, the Navy allowed him to perform a test dive at their primary experimental facility, adjacent to the Washington dive school. They also became a financial supporter of Keller’s ambitious thousand-foot dive.

To carefully scrutinize the operation, the Navy designated Dr. Robert Workman, one of their foremost decompression specialists, to be present on site. A few days after reaching Catalina in late November, Dr. Workman joined Dr. Bühlmann, the rest of Keller’s team, and various onlookers aboard Eureka, an experimental offshore drilling vessel provided by Shell Oil Co. Shell, like other oil and gas enterprises, had a vested interest in innovative techniques that could enhance the productivity of commercial divers. If the dive was successful, the company would receive Keller’s secret air mixture technology and thereby become an instant frontrunner in offshore oil exploration. Their interest was particularly relevant as offshore drilling initiatives were venturing into deeper waters, both off the California shore and in the Gulf of Mexico.

Resembling a huge can of soup, Atlantis stood seven feet tall and had a diameter slightly greater than four feet. Its structure featured an access hatch at the bottom and was adorned with an array of protruding pipes and valves, adding to its industrial appearance.

British journalist Peter Small (BSAC)

As a journalist, Peter Small intended to pen a first-hand narrative of the groundbreaking dive. On December 1, as part of a final preparatory dive, Small and Keller were lowered inside Atlantis to a depth of three hundred feet, where they spent an hour scuba diving outside the bell. During the decompression process within the bell, both divers experienced relatively mild symptoms of decompression sickness, commonly known as the bends. Keller felt the effects in his belly, while Small was afflicted in his right arm. Decompression sickness is still a relatively poorly understood phenomenon, and it remains unpredictable as to which part of the body it might affect.

Keller’s symptoms abated on their own that night, but Small’s discomfort lingered until he underwent recompression treatment. Despite this warning sign, Keller was determined to continue with the dive as planned, without conducting further incremental tests at increasing depths before the ambitious thousand-foot descent. His decision was likely influenced, at least in part, by the assembled crowd of journalists and other spectators eager to witness the historic dive. The constraints of time, finances, and equipment availability added to the pressure, compelling the team to proceed with the experimental dive as scheduled.

The diving bell Atlantis is lifted out of the water after Keller and the journalist Peter Small descended 1,020 feet to the Pacific Ocean floor in December 1962.

On Monday, December 3, around noon, Atlantis began its descent beneath the surface of the Pacific, enclosing its two divers within. The journey towards the ocean floor took under thirty minutes. Upon reaching the target depth of a thousand feet, a series of dark and chaotic moments ensued. Keller exited the bell to plant a Swiss flag and an American flag on the ocean floor. In the process, his breathing hoses became entangled with the flags, and after clambering back inside Atlantis, he lost consciousness.

The gas mixture had somehow become compromised. Peter Small also blacked out, despite never having left the diving bell. As Atlantis was hastily ascended to within two hundred feet of the surface, several support divers swam down to meet the bell. Tragically, one of these support divers, Christopher Whittaker, a young man of just nineteen, disappeared without a trace.

Pacific Ocean off Catalina Island (Erik Olsen)

Keller came to roughly a half-hour after the incident, and Small regained consciousness, but it took nearly two hours for him to do so. Upon awakening, Small engaged Keller in coherent questions about what had transpired. He reported feeling cold and, although he retained the ability to speak, see, and hear, he could not feel his legs. Despite not experiencing any pain, he was too weak to stand. Leaning against his Swiss counterpart, he drifted off to sleep as their decompression within the bell continued.

Several hours later, as Atlantis was being transported back to shore to Long Beach from the dive site near Catalina, Keller discovered that Small had ceased breathing and had no pulse. Desperate to revive him, Keller administered mouth-to-mouth resuscitation and cardiac massage, but to no avail. Small was cold and pallid. The remaining pressure inside the bell, about two atmospheres, was hastily released in a frantic effort to get Small to a hospital after being trapped inside Atlantis for eight hours. Tragically, upon arrival, he was promptly pronounced dead.

The Atlantis diving bell (Paul Tzimoulis)

The Los Angeles County coroner identified the cause of death as decompression sickness. An examination revealed that Small’s tissues and organs were filled with Nitrogen gas bubbles. However, Keller contended that other factors, such as a potential heart attack and the panic Small displayed upon reaching the thousand-foot mark, contributed to the tragedy.

Regardless of the underlying causes, the catastrophic dive to thirty atmospheres and the loss of two lives led to a rapid waning of interest in Keller’s previously sensational methods. The potential for failure of this magnitude had been a concern to many in the deep diving community and the day’s events set back research in the emerging field of saturation diving. Even before this event, saturation diving had only tepid support from the Navy, but this made some people loss faith in the technique. Of course, it would not be the end of saturation diving, not by a long shot. 

Hannes Keller in his later years. (Credit: Keller, Esther, Niederglatt, Switzerland)

Modern deep-water diving owes much to the groundbreaking experiments of Hannes Keller. His historic dive to 1,020 feet (311 meters) off Catalina Island was a remarkable achievement that captivated the world. Far from being a mere stunt, as some critics claimed, Keller’s dive was a meticulously planned scientific endeavor designed to push the boundaries of human exploration of the ocean depths. This Swiss adventurer’s pioneering work laid the foundation for advances in deep-sea diving techniques, leaving an enduring legacy in the field.

CALIFORNIA CURATED ART ON ETSY

Purchase stunning art prints of iconic California scenes.
Check out our Etsy store.

Christopher Swann, a diving historian, said the dive “was a milepost in the sense that it was the first time something like that had been done.”

Keller ended up living a rich and long life, dying on December 1, 2022, at at a nursing home in Wallisellen, Switzerland, near his home in Niederglatt. He was 88.

Support California Curated with a small donation.

Baja California Is Slowly Breaking Away from the Mainland and May One Day Become an Island

Baja California and the Sea of Cortez (Photo: Erik Olsen)
Click to buy us a cup of coffee? We’d appreciate it!

Geological forces are always at work, reshaping the planet, just usually on a timescale too slow for us to notice. But over the long haul, they can completely transform places we think of as fixed and familiar, like Southern California and northern Mexico. I’ve been down to Baja a bunch of times, including a few unforgettable multi-day kayak trips in the Sea of Cortez. Paddling past sheer cliffs and sleeping on empty beaches under the stars, it’s easy to feel like the landscape has been frozen in time. But that sense of permanence? It’s an illusion.

Baja California stretches like a crooked finger pointing toward the tropics, wedged between the restless Pacific and the calm, warm waters of the Gulf of California. This long, skinny slice of land, more than 1,200 miles from Mexicali to Cabo, is full of contrasts: sun-blasted deserts, jagged mountains, hidden oases and mangroves. But it’s not just a finger of land: it’s a fracture. Baja was ripped from mainland Mexico by slow, grinding tectonic forces, the Pacific Plate dragging it north and leaving the Gulf in its wake. And it’s still on the move.

Kayaking the Sea of Cortez out of Loreto, Mexico on the Baja Peninsula (Photo: Erik Olsen)

Every year, Baja creeps a little farther away from the continent, slowly widening the gap. Some scientists think that, millions of years from now, the whole rift could flood, turning parts of northern Mexico into a vast inland sea. It’s the continent, cracking apart right under our feet. it’s just taking its time.

This process is linked to the activity of the San Andreas Fault and other associated fault systems, which collectively form a boundary between the Pacific Plate and the North American Plate. The movement of these tectonic plates is a slow but relentless process, occurring over millions of years. (Slow, and yet as we’ve documented, there’s been quite a bit of movement over that long period of time).

The Pacific Plate is moving northwest relative to the North American Plate, and the San Andreas Fault system primarily accommodates this movement. In essence, the Baja California Peninsula is moving with the Pacific Plate alongside and away from the North American Plate. 

The separation is taking place at an average rate of about 2 to 5 centimeters per year. Over millions of years, these movements accumulate, leading to significant shifts in the geography of regions like Baja California. According to some geologists, within the next 20-30 million years, this tectonic movement could eventually break Baja and the westernmost part of California off of North America to create a vast inland sea, if not an island.

The movement of the continental crust in the area is due in part to seafloor spreading at a massive underwater seam called the East Pacific Rise. This mid-ocean ridge stretches from the southeastern Pacific near Antarctica all the way north into the Gulf of California. Its northernmost extension, known as the Gulf of California Rift Zone, reaches close to the mouth of the Colorado River, helping drive the slow but steady separation of the Baja California Peninsula from mainland Mexico.

Check out our Etsy store for California wildlife gifts.

That geological rift didn’t just shape the land—it created an entirely new sea. The story of Baja California’s tectonic journey isn’t just about earthquakes and shifting plates, it’s also a story of water. The Gulf of California, also known as the Sea of Cortez, is a geologically young sea, having formed around 5.3 million years ago when the Baja Peninsula began drifting northwest. That rifting process continues today, slowly widening the gulf and redrawing the landscape of northwest Mexico.

The azure waters of the Sea of Cortez (Photo: Erik Olsen)

This body of water is a critical habitat for marine life, including several species of whales and dolphins that depend on its warm waters. Jacques Cousteau, the famous French oceanographer, famously referred to the Gulf of California as “the world’s aquarium” due to its vast array of (declining) marine life.

The Sea of Cortez today is under threat from our short time so far on the planet. Unfortunately, overfishing and pollution, including nitrogen-rich runoff from the Colorado River, which (sort of) flows directly into the gulf, imperils wildlife. Nutrient flows can lead to a dramatic decrease in oxygen, depriving plants and animals of the life-giving gas. The potential extinction of the critically endangered vaquita (Phocoena sinus), represents one of the most urgent conservation crises in the region. The vaquita is the world’s most endangered marine cetacean, with estimates suggesting only a few individuals remain. This dire situation is primarily due to bycatch in illegal gillnets used for fishing another endangered species, the totoaba fish, whose swim bladder is highly valued in traditional Chinese medicine.

Habitat destruction is another growing concern, as mangroves, estuaries, and reefs, vital for the breeding and feeding of marine species, are increasingly destroyed to make way for tourism infrastructure and coastal development. Climate change intensifies these problems, with rising sea temperatures and ocean acidification threatening reefs and the broader ecosystem.

Baja California as seen in April 1984, from the bay of a Space Shuttle  (Photo: NASA)

The birth of the Sea of Cortez also has an intriguing connection to a body of water hundreds of miles to the north: the Salton Sea. The Salton Sea, California’s largest lake, sits in the Salton Trough, an area geologists consider a “rift zone,” an extension of the same tectonic forces at work in the Gulf of California.

As the North American and Pacific Plates continue their slow-motion dance, the area around the Salton Sea may sink further, eventually linking with the Gulf of California. If this occurs, seawater could flood the basin, creating a new body of water significantly opening the Sea of Cortez. As mentioned above, eventually this could lead to the full separation of the peninsula from the mainland. However, such a dramatic event is likely millions of years in the future, if it happens at all. Interestingly, the Salton Sea acts as a mirror, reflecting the past processes that led to the formation of the Sea of Cortez.

Salton Sea (Wikipedia)

The Sea of Cortez stands at a crossroads, shaped by both human impact and tectonic drift. Baja California is slowly pulling away from mainland Mexico, a process that could one day create a vast inland sea and dramatically reshape the region. While no one alive today will witness the full transformation, its ultimate impacts could be extreme—redrawing coastlines, shifting ecosystems, and isolating parts of southern California and Mexico in ways we can scarcely imagine.

Click to buy us a cup of coffee? We’d appreciate it!

Where the Sand on Southern California’s Beaches Comes From

Support California Curated with a small donation.

Southern California’s sandy beaches are more than just popular spots for surfing and sunbathing—they’re the product of a dramatic geologic story that’s been unfolding for millions of years. With their sweeping ocean views and turquoise waters, these iconic coastlines attract millions every year. But few people stop to think about how these beaches actually came to be.

To get the full picture, you have to go way back—about 200 million years, to the Mesozoic era. Back then, the land we now know as Southern California was underwater, part of a vast oceanic plate. As the North American continent drifted westward, it collided with and began to override the Pacific plate. This slow-motion crash, called subduction, set the stage for the coast we see today.

This subduction zone generated intense heat and pressure, melting portions of the oceanic crust and upper mantle. The resulting magma rose to the surface, forming a chain of volcanic islands and large underground magma chambers. Over time, these chambers cooled and solidified into granite, forming what’s now known as the Southern California batholith—an enormous mass of igneous rock that underlies much of the region. This tectonic activity also helped uplift and shape many of the mountain ranges we see today, including the Santa Monica and San Gabriel Mountains.

CALIFORNIA CURATED ART ON ETSY

Purchase stunning art prints of iconic California scenes.
Check out our Etsy store.

Beach sand, particularly in Southern California, is primarily composed of quartz and feldspar mixed with silvery mica and milky quartz. These minerals originally existed in the granite of the local mountains, miles from the shoreline. Studies have shown that much of the sand on Southern California beaches actually comes from the San Gabriel mountain range. 

“Sediment that’s derived from granite-type watersheds is generally comprised of a lot of quartz,” says UCLA geography professor Tony Orme. “It tends to be light in color.”

San Gabriel Mountains

The San Gabriel Mountains are part of the Transverse Ranges, are known for their rugged terrain, diverse ecosystems, and recreational opportunities, stretching approximately 68 miles from Los Angeles County to San Bernardino County.

It may be surprising to learn that the San Gabriel Mountains, towering over Los Angeles, play a critical role in forming the region’s stunning beaches. They are, in fact, the primary source of much of Southern California’s beach sand, particularly around Los Angeles. But how does this granitic mountain material end up miles away on the beach?

The answer lies in the forces of erosion and weathering. The mountains’ granite is gradually worn down over time by rain, wind, and cycles of freezing and thawing. This erosion process, which can take millions of years, results in smaller and smaller particles. Rainfall and streams transport these eroded particles down the mountain slopes and into the regions rivers.

Southern California beach

These rivers, such as the Los Angeles and San Gabriel Rivers, act as conveyor belts, carrying the eroded material – the future sand of our beaches – toward the Pacific Ocean. Renowned geomorphologist Douglas Sherman of the University of Alabama has extensively studied these sediment transport processes, highlighting their importance in coastal formation.

Sand continuously migrates from land to sea. As rivers met the ocean, they deposited their sediment load, forming deltas. Coastal currents then took over, redistributing these sediments along the shoreline, a process known as longshore drift. Waves, powered by the coastal winds, continually pushes this sediment onto the shore, gradually creating the wide, sandy beaches we enjoy today.

This ongoing transfer is accompanied by watershed run-off and the erosion of bluffs and hillsides, which carry sand toward the beach. Grains of sand then embark on a southward journey along the coast, while the smaller sediment particles are swept further offshore and deposited deep on the ocean floor.

Lifeguard tower (Erik Olsen)

While there is still widespread belief among geologists that most of California’s sand originates in the mountains, two relatively recent studies conducted by researchers at the University of California, San Diego have suggested that another key source of erosion might be the grand sea cliffs of the region.

“Much to our surprise,” expressed Scott Ashford, formerly a professor of engineering at UCSD, and now at Oregon State, who employed a mobile laser imaging system to examine coastal formations for one of the studies. “It’s revealing that our comprehension of the beach system isn’t as thorough as we’ve presumed.”

CALIFORNIA CURATED ON ETSY

Purchase stunning art prints of iconic California scenes.
Check out our Etsy store.

His research analyzed six years’ worth of imaging data from the 50-mile (80-kilometer) coastline stretching from Dana Point to La Jolla. Previously, geologists had conjectured that up to 90% of the beach sand in this sector originated from deposits transported by coastal rivers, but Ashford’s research indicated that the sea cliff erosion accounts for some 67% of Southern California’s beach sand. However, since Ashford’s study was focused on such a small area of the coast, many geologists are wary of embracing his conclusions.

The coastal journey of the sand concludes either when it is blown inland to form dunes or more frequently, when it descends into a submarine canyon, such as Monterey Canyon in Northern California. The deep underwater chasm of a canyon signifies the endpoint of a littoral cell. A littoral cell is a unique coastal region where sand embarks on a journey from land into the ocean, traverses down the coast, and then exits the system. The volume of sand accessible to beaches equals the quantity entering the littoral cell minus the quantity exiting. Changes to this sand budget can result in the contraction or even complete vanishing of beaches.

Hermosa Beach (Erik Olsen)

The formation of Southern California’s beaches is not a completed process but an ongoing one. Waves and currents continue to shape the coastline, sometimes depositing sand to widen the beach, and at other times eroding the shoreline. Los Angeles has paved most of its major rivers, reducing the amount of sand that comes from the mountains onto the beaches. In fact, it is not uncommon for Southern California beaches to be missing close to 50% of their historical sand supply.

California has added sand to its beaches for decades through projects called “nourishment”. These projects are often used to restore eroded beaches and protect against sea level rise. Sand is typically dredged offshore and pumped onto the shore, where trucks spread it around. The goal is to widen the beach so that wave energy breaks sooner and dissipates towards the bluff face.

Rosanna Xia’s book, California Against the Sea: Visions for Our Vanishing Coastline (2023) is an excellent source of information on California beach erosion and the threats posed by the loss of significant portions of the coast. The book explores how human activities like coastal development, urbanization, and dam construction have intensified natural erosion processes. She provides a historical context for these developments and their long-term impacts, while also exploring innovative adaptation strategies and community-led efforts to protect the coastline. Balancing a sense of urgency with cautious optimism, Xia presents a vision for a resilient future where informed policies and sustainable practices can help safeguard California’s coastal treasures for generations to come.

Los Angeles River

Understanding the geological history of Southern California’s beaches not only adds depth to our appreciation of these natural wonders but also highlights the need for careful stewardship. By minimizing our environmental impact, reducing development and mitigating the effects of climate change, we can ensure that these incredible landscapes continue to evolve and endure for generations to come.

Support California Curated with a small donation.

Why Are Dinosaur Fossils So Scarce in California?

Hadrosaur on ancient California landscape. Hadrosaurs like this AI generated one are among the very few dinosaurs whose fossils have ever been found in California.
Support California Curated with a small donation.

You’ve surely seen those dramatic museum displays: fearsome T-Rex skulls, triceratops horns, towering brachiosaur skeletons – tangible reminders of a world with giant animals that roamed our planet millions of years ago. Some states are rich in the fossils of ancient dinosaurs. Montana, Wyoming, Utah all have rich fossil records. But not California. Very few dinosaur fossils have ever been found in the Golden State.

But why? We’ve got Hollywood, Silicon Valley, lots of oil, and the Giant Redwoods, but where are our prehistoric dinosaur residents hiding?

To understand this prehistoric puzzle, we have to venture back into the geologic past, and also consider some unique aspects of California’s geographical and geologic evolution.

Dinosaurs were mostly present during the Mesozoic Era, from about 252 million to 66 million years ago. The Mesozoic is divided into three periods: the Triassic, Jurassic, and Cretaceous. The dinosaurs reign likely ended with a massive meteorite impact that caused a mass extinction, wiping out the dinosaurs and up to 80% of life on Earth.

(There’s a cool California story related to this discovery.)

While dinosaur fossils are found around the globe, their distribution is far from even. Fossilization itself is a relatively rare event that depends on several specific conditions. Generally, fossilization requires rapid burial to protect the remains from scavengers and environmental factors, as well as a lack of oxygen to slow down decay. Over time, minerals gradually replace organic material, preserving the structure and creating a fossil, but only a small fraction of organisms ever undergo this process.

Jack Horner, Curator of Paleontology at Museum of the Rockies, provides scale for Tyrannosaurus rex fossils at excavation site near the Fort Peck Reservoir, Fort Peck, Mont., June 1990. (Photo: courtesy Museum of the Rockies

So, when a dinosaur died, its body needed to be quickly covered by sediment, like sand, mud, or volcanic ash. This prevented the remains from being scavenged or decomposed and allowed for the slow process of mineralization, where bones and teeth gradually turn to stone.

Even if these conditions were met, the resulting fossils had to survive millions of years of geologic processes, such as erosion, plate tectonics, and volcanic activity. To find dinosaur fossils today, the layers of rock in which they are embedded must be exposed at the Earth’s surface.

But now here’s where California’s unique geologic history comes into play. Most of the land we see today in California wasn’t even above sea level during the Mesozoic Era, instead it was submerged beneath the Pacific Ocean. Only small, scattered volcanic islands or bits of uplifted crust occasionally broke the surface, shaped by the intense movement of tectonic plates. That means there were no T. rexes or Stegosaurs ambling through Yosemite Valley…which, by the way, hadn’t even formed yet.

California’s active geology works against fossil preservation. The state sits on the boundary of tectonic plates (the Pacific and North American plates), resulting in significant geological activity including earthquakes, volcanic activity, mountain building, and erosion. These processes tend to destroy fossils rather than preserve them.

Head section of Olenellid trilobite in a Latham Shale slab. (Credit: National Park Service)

California, in the form we recognize today, is relatively new land that finally began rising out of the ocean near the end of the dinosaur age, as mountain ranges like the Sierra Nevada started to form and ancient sea basins uplifted. While these earlier conditions weren’t favorable for preserving land-dwelling dinosaur fossils, they did leave behind a rich marine fossil record, including ammonites, marine reptiles, and countless microfossils.

That said, there have been several discoveries of particular animals in California, representing animals much later in the dinosaur story. The majority of the dinosaur fossils found in California are the bones of hadrosaurs, duck-billed dinosaurs that lived during the Late Cretaceous period. These herbivorous dinosaurs thrived in what was once a coastal plain environment, and their remains have been uncovered in parts of California like the Point Loma Formation near San Diego, the Panoche Hills area near Fresno, and in Baja California.

Mosasaur artists rendering (Wikipedia)

While much of California was underwater during the Late Cretaceous, it was home to mosasaurs, large carnivorous marine reptiles that lived in oceans all over the world. These fearsome predators had long, streamlined bodies with powerful fins and jaws lined with sharp teeth. They hunted fish, ammonites, and possibly even other mosasaurs. Some species grew as big as modern whales and ruled the seas at the very end of the dinosaur age. Mosasaurs shared the world with creatures like Triceratops and Tyrannosaurus, but they vanished along with the dinosaurs during the mass extinction at the close of the Cretaceous. Today, paleontologists recognize mosasaur fossils by distinctive features on their skeletons, including unique muscle attachment scars and specialized bone knobs.

CALIFORNIA CURATED ART ON ETSY

Purchase stunning art prints of iconic California scenes.
Check out our Etsy store.

Back to hadrosaurs, however. There is the duck-billed plant-eater Augustynolophus, a member of the hadrosaur family, which recently was named the official state dinosaur of California. All known specimens of Augustynolophus have been found only in California, in particular the Moreno Formation in the San Joaquin Valley. Only two specimens have ever been found. The first fossil was uncovered in Fresno County in 1939. The second was discovered nearby in 1941 in San Benito County, according to the Natural History Museum of Los Angeles County website. Named after paleontologist William J. Morris and NHMLA patron Gretchen Augustyn, Augustynolophus remains one of few dinosaurs that have been discovered in the state.

Artists recreation of the hadrosaur Augustynolophus by the Natural History Museum of Los Angeles County

As mentioned above, the action of plate tectonics, the slow but powerful movements of sections of the Earth’s crust, has significantly affected California’s fossil record. Over millions of years, California has been built from pieces of the Earth’s crust that traveled here aboard tectonic plates.

Much of the rock we see at the surface today, especially along the coast and in the western mountains, arrived during the Cenozoic Era, after the age of dinosaurs. These younger rocks, while not bearing dinosaur fossils, have yielded rich caches of mammal fossils, including creatures like saber-toothed cats, mammoths, and dire wolves, which roamed California long after the dinosaurs.

In recent years, paleontologists have begun to find more dinosaur fossils in California, albeit still far fewer than in states like Utah, Montana, or Wyoming. These discoveries, often of marine animals or those who lived near the coast, are expanding our understanding the ancient Californian landscape.

Saber-toothed cat (State of California Capitol Museum)

In 2022, a remarkable fossil discovery was made during a construction project at San Pedro High School in Los Angeles. The excavation revealed a massive trove of marine fossils from the Miocene Epoch, dating back around 5 to 23 million years (so, not technically dinosaur fossils). Among the finds were the remains of ancient whales, sharks, fish, and mollusks, offering a rare glimpse into Southern California’s prehistoric past when the region was submerged under a warm, shallow sea. This discovery provided paleontologists with valuable insights into the marine ecosystems that once thrived in the area.

Among the fossils found under San Pedro High School are juvenile megalodon teeth, right, the great white shark’s ancestor; those from mako sharks, center; and from smaller sharks.
 (Wayne Bischoff / Envicom Corp.)

In addition to the marine fossils, a few terrestrial remains were also uncovered, hinting at a nearby coastline that once supported a variety of land animals. The discovery of such well-preserved fossils captured the attention of scientists and the local community alike, briefly turning the San Pedro High School campus into an unexpected center of scientific excitement. For students and residents, the find offered a cool reminder of the ancient worlds buried just beneath their everyday lives.

While California’s record of dinosaur fossils is relatively sparse, its mammal fossil record is nothing short of astonishing. Sites like the La Brea Tar Pits in Los Angeles preserve an incredible array of Ice Age mammals, from saber-toothed cats and mammoths to giant ground sloths. These fossils provide an unparalleled window into the vibrant ecosystems that thrived long after the age of dinosaurs ended, showcasing California’s rich and varied prehistoric past.

saber toothed cat
Saber-toothed cat fossil skeleton at the La Brea Tar Pits in Los Angeles (Photo: Erik Olsen)

While it might be tempting to feel a little disappointed that California doesn’t have an abundance of dinosaur fossils, that’s simply the way the landscape evolved. But there’s still plenty to celebrate. California’s unique geologic past has produced a vibrant fossil record of other ancient life — from towering prehistoric sequoias to tiny, long-lost plankton. Every fossil, big or small, offers a glimpse into the rich, complicated, and ever-changing story of this remarkable place we call California.

Support California Curated with a small donation.

Genetic Guardians: The Asilomar Conference and its DNA Diplomacy

How a gathering of the world’s top genetic scientists helped create a roadmap for responsible biology.

Asilomar Conference Grounds Interior
Support California Curated with a small donation.

In 1975, amidst the California coastal dunes of Asilomar near Monterey, a groundbreaking conference was held that would influence the direction of biotechnology and the course of scientific research for decades to come. This was the Asilomar Conference on Recombinant DNA, an assembly marked by both controversy and consensus. Its aim was not just to debate the scientific merits of a new and potentially groundbreaking technology but also to discuss its potential impacts on society and the environment. (Berg and others had met as Asilomar before in 1973, but that initial meeting resulted in little more than a realization there would have to be more discussion).

DNA

Among the seventy-five participants from sixteen countries were Paul Berg, a Nobel laureate, Maxine Singer, a prominent molecular biologist, and many others, each bringing their own perspective and expertise to the table. They recognized the vast potential that recombinant DNA (rDNA) technology, the process of combining DNA from different species, had to offer but were equally cognizant of the potential risks involved.

Berg was awarded the Nobel Prize in Chemistry for his work on nucleic acids, with a focus on recombinant DNA. Berg had first-hand experience with the transformative potential and risks of the technology. His ground-breaking experiments with recombinant DNA in 1972 and subsequent calls for a moratorium on such work had spurred the idea of the conference.

Maxine Singer, another significant contributor, was known for her advocacy for scientific responsibility and ethical considerations. She played a crucial role in drafting the initial letter to the journal “Science” advocating for a voluntary halt on certain types of rDNA research until its potential risks could be better understood. In 2002, Discover magazine recognized her as one of the 50 most important women in science.

CALIFORNIA CURATED ON ETSY

Purchase stunning art prints of iconic California scenes.
Check out our Etsy store.

The conference was the outcome of dramatic advances in molecular biology that took place mid-century. In the atomic age of the 1950s and ’60s, biology was not left behind in the wave of transformation. A pioneering blend of structural analysis, biochemical investigation, and informational decoding began to crack open the mystery of classical genetics. Central to this exploration was the realization that genes were crafted from DNA, and that this intricate molecular masterpiece held the blueprints for replication and protein synthesis.

Paul Berg (Photo: Stanford University)

This was a truth beautifully crystallized in the DNA model, a triumph of scientific collaboration that arose from the minds of James Watson, Francis Crick, and the often under-appreciated Rosalind Franklin. Their collective genius propelled a cascade of theoretical breakthroughs that nudged our understanding from mere observation to the brink of manipulation.

The crowning achievement of this era was the advent of recombinant DNA technology – a tool with the potential to rearrange life’s building blocks at our will. As the curtain lifted on this new stage of biological exploration, the promise and peril of our increasing control over life’s code started to unfurl.

Asilomar Conference Building

The ability to manipulate genes marked nothing less than a seismic shift in the realm of genetics. We had deciphered a new language. Now, it was incumbent upon us to assure ourselves and all others that we possessed the requisite responsibility to utilize it.

As Siddhartha Mukherjee put it in his excellent book The Gene: An Intimate History, “There is an illuminated moment in the development of a child when she grasps the recursiveness of language: just as thoughts can be used to generate words, she realizes, words can be used to generate thoughts. Recombinant DNA had made the language of genetics recursive.”

The conference served as a forum to deliberate the safety measures that would be needed to prevent accidental release of genetically modified organisms (GMOs) into the environment, the ethical considerations of manipulating the genetic code, and the potential implications for biological warfare. It was as much about the science as it was about its potential impact on society, mirroring aspects of the Pugwash Conferences that discussed nuclear arms control during the Cold War.

Participants in the First Pugwash Conference in 1957 in Pugwash, Nova Scotia, Canada. Notable figures included Joseph Rotblat, Bertrand Russell, Leo Szilard, Igor Tamm (pugwash.org)

Much like the Pugwash Conferences in Pugwash, Nova Scotia, Canada, brought together scientists from both sides of the Iron Curtain to discuss the implications of nuclear technology, the Asilomar Conference sought to bridge the divide between the proponents and critics of genetic engineering. Just as nuclear technology held the promise of unlimited power and the threat of unparalleled destruction, recombinant DNA offered the allure of potential solutions for numerous diseases and the specter of unforeseen consequences.

Another analogy might be the two-page letter written in August 1939 by Albert Einstein and Leo Szilard to alert President Roosevelt to the alarming possibility of a powerful war weapon in the making. A “new and important source of energy” had been discovered, Einstein wrote, through which “vast amounts of power . . . might be generated.” “This new phenomenon would also lead to the construction of bombs, and it is conceivable . . . that extremely powerful bombs of a new type may thus be constructed. A single bomb of this type, carried by boat and exploded in a port, might very well destroy the whole port.” 

The Einstein–Szilard letter

The Asilomar Conference reached a consensus that with proper containment measures, most rDNA experiments could be conducted safely. This resulted in a set of guidelines that differentiated experiments based on their potential biohazards and suggested appropriate containment measures. This framework, later adopted by the National Institutes of Health (NIH) in the United States, provided the bedrock for the safe and ethical use of rDNA technology.

The decisions made at Asilomar had far-reaching implications for both science and society. By promoting a culture of responsibility and precaution, the conference effectively prevented a public backlash against the nascent field of genetic engineering, allowing it to flourish. Moreover, it set a precedent for scientists to take an active role in the ethical and societal implications of their work.

“The most important lesson of Asilomar,” Berg said, “was to demonstrate that scientists were capable of self-governance.” Those accustomed to the “unfettered pursuit of research” would have to learn to fetter themselves.

CRISPR

Today, the spirit of Asilomar lives on in the field of synthetic biology and discussions around emerging technologies such as CRISPR and gene drives. It underscores the importance of scientific self-regulation, public dialogue, and transparent communication in navigating the ethical minefields that technological advancements often present.

The Asilomar Conference was a milestone in scientific history, a demonstration that scientists are not merely the creators of knowledge but also its stewards. It showed that with open dialogue, proactive self-regulation, and a deep sense of responsibility, we can both harness the promise of scientific breakthroughs and mitigate their potential risks.

Support California Curated with a small donation.

A Deep Dive into the World of California’s Orcas: Majestic Ocean Predators

The marine ecosystem of California is both vibrant and diverse, boasting an array of majestic creatures, from the smallest microorganisms to the most massive marine mammals. One of the ocean’s most iconic inhabitants, the orca or killer whale (Orcinus orca), has attracted a significant amount of fascination and intrigue due to its striking appearance, formidable hunting abilities, complex social structure, and enduring presence in human culture.

In May, an uncommonly large grouping of orcas for Northern California — around 20 to 24 animals — was spotted by a whale-watching tour off the coast of San Francisco, likely gathered together to celebrate a successful hunt for sea lions or seals.

“I screamed ‘orca!’” Michael Pierson, an Oceanic Society naturalist leading the tour, told KTLA “those distinct dorsal finds poking out of the water.”

“It was really, really special,” Pierson said.

In June, a crowd of 30 killer whales met for a whale party in California’s Monterey Bay. Observers said they did belly flops into the water, slapped the waves with their flukes and spumed water from their blowholes, surprising marine biologists who had never seen the animals engage in such playful behavior for such a long period.

“Just like kids that are in a park, they get excited and play with the other kids and may be more active,” said Nancy Black, a marine biologist with Monterey Bay Whale Watch and the director of the California Killer Whale Project. “The little ones were wrestling and rolling like a bunch of puppies.”

An astonishing video last May showed a group of 30 orcas attacking two grey whales near Monterey. “We were able to observe the unique hunting strategies of the pods and the rarely seen defensive strategies of the two Grays,” Monterey Bay Whale Watch said. “The battered gray whales eventually made it to shallow water, and the orcas broke off.”

Black’s California Killer Whale Project has spent thirty years cataloging the killer whales that spend time in Monterey Bay. The group is able to recognize many of the whales by their spotted markings and the common tail notches.

The whales are rarely seen further south of Monterey, but another whale-watching tour off the coast of Southern California spotted a pod of killer whales last April, just off Newport Beach. The viewing included a rare glimpse of a three-year-old albino calf named Frosty due to its white appearance. (The white skin of the whale may not be albinism, per see. Several known conditions cause certain animals, including orcas, to look white. One condition is the extremely rare leucism, which is a genetic condition that causes the unusual coloring and the pigmentation of the skin to be paler. The other is Chediak-Higashi syndrome, an inheritable immune deficiency that can cause partial albinism.)

Jumping Orca

The term “killer whale” is a bit of a misnomer. Killer whales are actually dolphins and the largest species of the family Delphinidae. An adult male can typically grow up to 26 feet long and weigh up to 6 tons, while females are typically smaller. That said, The largest recorded male killer whale was 9.8 m (32 ft.) in length and weighed 10,000 kg (22,000 lbs.) The largest recorded female was 8.5 m (28 ft.) and weighed 7,500 kg (16,500 lbs.). They are known for their distinctive black and white coloration, with a dark dorsal side and a lighter ventral side. The tall, triangular dorsal fin of a male orca, which can reach heights of up to 6 feet, is a distinguishing characteristic.

Orcas are warm-blooded mammals, with an impressive ability to regulate their body temperature even in the cold waters off California’s coast. Their thick layer of blubber not only insulates them but also acts as a reservoir of energy when food is scarce.

Killer whales are top predators and display a diverse diet, although their food preference varies depending on the population. They are known to feed on fish, squids, seals, sea lions, and even other whales. In California waters, salmon, particularly Chinook, is a crucial part of their diet, but they also consume marine mammals such as sea lions and seals.

In orca societies, females generally choose the mates. Gestation lasts for about 17 months, with females giving birth every 3 to 10 years. The mother-calf bond in orcas is remarkably strong, often lasting for a lifetime. Orcas are known for their complex social structures, including matrilineal groups comprising grandmothers, mothers, and their offspring.

Killer whales are found in oceans worldwide, from the frigid Arctic and Antarctic regions to tropical seas. In California, they are most frequently sighted in Monterey Bay, the Gulf of the Farallones, and along the northern coast near the Oregon border. They migrate following their prey, and their appearance in California waters often aligns with the migration of gray whales, a favorite prey species.

Orcas have been popular in human culture, depicted in indigenous art, folklore, and mythology. Their image was catapulted into the modern mainstream by the 1993 film “Free Willy.” Yet, their captive display in marine parks like SeaWorld has sparked controversy and fueled a significant shift in public perception towards marine mammal captivity. The 2013 documentary “Blackfish” shed light on the stressors faced by these magnificent creatures in captivity, leading to policy changes and declining popularity of such exhibits.

Orcas are not typically dangerous to humans in the wild, and there are very few documented cases of wild orcas attacking people. However, tragic incidents involving captive orcas and their trainers have occurred, which some attribute to the psychological stress of captivity.

Despite their wide range and lack of natural predators, orcas face significant threats due to human activities. These include pollution, overfishing of their prey, habitat degradation, and noise disturbances. In some parts of the world, orcas are hunted for their meat and blubber.

A female resident orca whale breaches while swimming in Puget Sound near Bainbridge Island, Wash., as seen from a federally permitted research vessel. The National Marine Fisheries Service has finalized rules to expand the Southern Resident orca’s critical habitat from the Canadian border down to Point Sur, Calif., adding 15,910 square miles, (41,207 square kilometers) of foraging areas, river mouths and migratory pathways. (AP Photo/Elaine Thompson, File)

All killer whales are protected under the Marine Mammal Protection Act (MMPA) and the Southern Resident population is listed as an endangered species under the Endangered Species Act (ESA).

The majesty and power of the orca have undeniably earned it a special place in human imagination and culture. Yet, it’s crucial to understand and respect these creatures in their natural habitat, to learn from them, and to work towards preserving the marine ecosystems they call home. California’s orcas are a testament to the incredible life thriving in our oceans, a life we must commit to protecting.