Sunday, August 29, 2021

The Other California: There's More Out There Than The The Tar Tar Pits (and The Doing of a Good Thing at the Carpinteria Bluffs)


The first thing to know in this post is that this was once my home. My small growing family spent three years in the cramped condominiums across Highway 101 from this spot on the Santa Barbara coast near Carpinteria. It was the 1980s shortly after I finished my degree and I was working as a lab teacher at Santa Barbara City College. They were good years, and many may wonder why I moved to a dusty farm town in the Central Valley for my 30 year career. It's a fair question, but I've never regretted it.

Be that as it may, Carpinteria turned out to be a nice place to visit 30 years on, and I was pleased that while some things have changed, others have not. When we lived there, it was a pleasant 1/4 mile walk to the Carpinteria Bluffs, a roughly 60-acre tract that had somehow escaped development over the years. Given the level of the land utilization along the coastal terraces from Goleta to Ventura, this stood as some kind of minor miracle. It's also a minor geological miracle that the flatland even exists at all. The Santa Barbara coastline is a prime example of a "geologically active" place.

The Santa Barbara coast really stands out on a map of California. While most of the state's coasts are oriented towards the north-northwest, the stretch from Point Conception to Ventura is distinctly east-west, paralleling the orientation of the Channel Islands, several tens of miles offshore. Geologists call this region the Transverse Ranges for this reason. This strange structural knot in southern California extends eastward to the San Bernardino Mountains and Joshua Tree National Park.

The origin of the structural twist is wild...when the San Andreas fault originated, it mostly carried crust to the northwest, but the part of the crust that is now the Transverse Ranges was twisted nearly 90 degrees to the east-west orientation that it has today (you can see a great animation and explanation of the process at this link). Getting caught in the machinery of the fault was not gentle either. Compressional forces pushed the crust upwards into mountains more than 10,000 feet high, and caused the crust to sink in other places. The Ventura and Santa Barbara basins contain tens of thousands of feet of marine sediments deposited in just a few million years. The region contains some of the thickest Cenozoic-aged sediments known from anywhere in the world. And the sediment contains prodigious amounts of petroleum and natural gas, with some consequences that will be noted later in this post.
The fact is that most of coastal Central California is mountainous, and in many places the mountains rise directly from the sea, leaving little or no flat surfaces for either settlement or transportation routes. Flat terraces are prime real estate, and most of these were developed early on. Carpinteria was only the latest of settlements over the last several thousand years. The Chumash had a village noted by Cabrillo in 1541 called Mishopshnow. They were canoe-builders, and the woodworking that was going on there is the reason for the name Carpinteria ("carpentry shop").

The terraces were also the result of active geological processes. Thousands of years of waves washing back and forth flattened the beach areas forming a wave-cut bench. These benches were lifted out of the water by continued tectonic uplift (no doubt accompanied by occasional severe earthquakes).
I'll never quite know why the Carpinteria Bluffs escaped industrial development during the last century. When we lived there in the 1980s, we heard of ambitious plans for the "barren" terrace, and it seemed a sure thing that this pleasant stretch of coast would disappear soon after we moved away, yet when we returned last month for a visit, I was thrilled to see it remained much as it was. I learned that the 1990s was a contentious period during which the people of Carpinteria fought a pitched battle to keep the bluffs as open space. In 1998, the volunteers managed to raise just short of 4 million dollars to purchase the land to form a permanent nature preserve. 
The Santa Ynez Mountains rise dramatically above Carpinteria. They are composed of sandstone, siltstone, and shale layers that were on the bottom of the sea only a few million years ago.
The preserve can hardly be described as a wilderness, given its location between the 101 Freeway and the busy railroad tracks, but a short series of walks reveal incredible views of the coastline, beaches, and the Channel Islands far offshore. During particularly heavy storms I can remember hearing the concussion of the huge waves that pounded the cliffs from a quarter mile away in our condo.
A section of the beach has been seasonally closed to provide a safe haven for Harbor Seals who use the beach for birthing their pups. Around a hundred of them utilize the area.
When we first moved there, we found another reason that one might avoid walking on this particular beach. At the conclusion of our walks we would find that there was a considerable amount of tar covering our shoes, or worse, our feet. It was hard to get off, and seemed omnipresent. It was easy to blame the offshore oil rigs or the onshore petroleum processing facility just to the west, but the truth was the tar was natural. Which brings us to the other subject of the day concerning Carpinteria: the tar!
The Spanish Language is beautiful. It's been said that reading a grocery list in French sounds sexy, but Spanish is muy bonita. The place names in California attest to this fact. For example in my area alone we have poetic place names like Merced, Madera, Manteca, Los Banos, and Escalon. Merced translates into the equally poetic name "Mercy", but the others are in order "Wood", "Lard", "The Bathrooms", and "Step".

And sometimes we kind of mix up our translations into unnecessary repetition. Most specifically, the La Brea Tar Pits. The most literal translation is "The The Tar Tar Pits". The La Brea Tar Pits in the Hancock Park area of Los Angeles are justly famous for the fossil collections that have come from one of what are said to be only five natural tar pits in the world (I can't confirm this claim, but I'm going with it).'s not the place I'm talking about in this post. It turns out that two of the other four tar pits are in California, and they are obviously far less known. One is in McKittrick near Bakersfield, and the other is in, of all places, Carpinteria.
File:Layers of stone and tar at Carpinteria, CA.jpg - Wikimedia Commons
Tar results when petroleum escapes to the surface and loses some of its volatile components, becoming a sticky gooey mess. In the coastal cliffs at Carpinteria, the near vertical layers of the Monterey Shale give way to the horizontal layers of the coastal terraces. The Monterey is the source of much of the oil that is pumped from the ground in California, but at Carpinteria, it is emerging from the rocks like a very, very slow spring. The tar deposits are present over dozens of acres in the area, but are mainly exposed in the sea cliffs and on the beach just west of the Carpinteria Bluffs, and within the lands of Carpinteria State Beach. 
Tar Pits Park (Carpinteria) - 2021 All You Need to Know BEFORE You Go (with Photos) - Tripadvisor
The tar was utilized by the Chumash people for centuries, and as such can be described as the first petroleum enterprise in North America. The tar was traded for use as an adhesive, caulking, and waterproofing. The Chumash made use of the material in their construction of their plank canoes. 

European colonizers and invaders also made use of the tar deposits, and in the late 1800s and early 1900s it was used to pave roads in the area. Eventually the pits were abandoned and utilized as a garbage dump. 

Some paleontologists came to realize that the tar was an important fossil resource. Excavations between 1926 and 1928 revealed 25 plant species, 55 species of birds and 26 species of mammals according to the Carpinteria Valley History Society. The animals are similar to those found at La Brea, including Mammoths or Mastodons, Saber tooth Cats, Dire Wolves, Giant Ground Sloths, horses, and camels. The birds are even more diverse, due to being a coastal habitat, unlike the plains at La Brea. The plant fossils include eight conifer species showing that the during the ice ages the coastal environment was cooler and more moist, much like the Monterey Coast to the north.
Source: California State Parks

When I worked at SBCC there was no internet, and I was only vaguely aware that there had been tarpits somewhere in the area. So it was that I never realized the value of the irritating pollutant on the beach that ruined a number of pairs of my shoes. If you visit and mess up your own shoes, just remember, it's important history!

The Other California is my long-running series of places to see in our state when you've seen all the places on the postcards!

Friday, August 20, 2021

The Other California: Catch it While You Can, the Devil's Slide

California is nothing if not audacious. Our state possesses so many incredible landscapes known throughout the world: alpine mountain ranges, volcanoes, deserts, and of course the legendary California coastline. The coastline in particular has garnered a lot of attention over the years to the extent that roadbuilders tried to provide vehicular access to practically all of it. There are only a few short stretches of coast, especially in the north state, where wilderness reigns instead of highways. Highway 1 is a spectacular engineering feat for better or worse, providing some of the most astounding views a driver could ever hope to see.

But this incredible feat of engineering didn't come without serious costs and continuing hazards. Hardly a year goes by in which some portion of Highway 1 isn't shut down by mudflows and landslides. The Big Sur section of the coast has been especially hard hit in recent years. But there is one part of the highway that we Californians constantly heard about in the news, but not any longer. It just sort of disappeared from the public consciousness. It's a section between Pacifica and Half Moon Bay called the Devil's Slide.

One needs only to look at the Google Earth image (above) to see the insanity of trying to build and maintain a road across the coastal cliffs here. The near total lack of vegetation is an immediate clue to the instability. A closer look at the geology of the rocks exposed in the cliff reveals a complex mess. To the right is the bold cliff labeled on the map below as Devil's Slide, although that particular rock is not the source of the problem. It's a relatively coherent intrusive complex called the Granitic Rock of Montara Mountain. The unit consists of granite and quartz diorite, which to most humans looks like granite. It formed about 86 to 93 million years ago as part of the Sierra Nevada batholith. Being found along the coast, it seems a bit out of place, and it truly is. It was sliced off the south end of the Sierra Nevada by the San Andreas fault system and transported several hundred miles north at the furious rate of about 2 inches per year. 

The problem child of this geologic mess is the gray colored unit labeled Tss on the geologic map below. It is an unnamed sequence of sandstone, shale, and conglomerate of Paleocene age, from around 55-60 million years ago, just after the great extinction that wiped out the non-avian dinosaurs and many other species. These weakly consolidated sedimentary rocks have been severely deformed and sheared by nearby fault zones into a jumbled mass of unstable blocks prone to sliding. The main slide surface is about 150 feet beneath the surface, and the entire unstable block is 4,000 feet long, and as much as 900 feet high.

It was a treacherous slope, but engineers (well-educated or not) love a challenge. The first attempt at building a road came in the late 1800s when a road was carved about 100 feet above the present trail. Landslides and slope failures soon commenced, and by 1914 the road was abandoned in favor of a winding route on the other side of San Pedro Mountain (which serves today as a fire lane). 

Then the railroad designers took their turn, putting in a railway on the lower part of the cliff in the early 1900s. The slopes disagreed with the railway, and the tracks were abandoned by 1920 (the 1906 earthquake did not help). Then in 1936, the roadbuilders were ready to try again. Highway 1 was being constructed along much of the Central Coast of California, and the engineers decided they simply must have a highway across the Devil's Slide. It was finished in 1937.
The problems of course began right away. Slope failures caused major closures of the highway, in some instances for days, in others weeks, and in 1995, five months. Numerous fixes were proposed, but most would have caused severe environmental disruptions in the marine ecosystem below, and unwanted urban growth above (an improved and widened freeway would have brought commuters to Half Moon Bay). So the status quo continued (fix the breaks and keep the damaged road open as much as possible). Driving the highway was an exhilarating and bumpy experience, and for geologists it was a frustrating adventure because there was no safe place to stop and study the geology of this fascinating case study in slope failure. 

Another solution gained steam in the early 2000s: a tunnel bypass. What was proposed were two single lane tunnels underneath San Pedro Mountain. At 4,000 feet each, they would be among the longest of tunnels in California, and would end up costing 'only' a third of a billion dollars. The Tom Lantos Tunnels were completed in 2013, and the transportation saga of traversing the Devil's Slide appeared to be over. 
So what to do with the old highway? It could have simply been abandoned like the nearby WWII defense installations, but a better idea emerged: convert the old highway into a hiking trail. San Mateo County took over the property and converted the highway into a 1.3 mile long hiking and biking trail, complete with parking at both ends, restrooms, and a series of useful interpretive signs. It opened in 2014, but I didn't get a chance to explore it until last week.
The paved trail was in excellent condition. Maybe the lack of heavy truck traffic eases some of the pressure on the slope. There are great exposures of the rocks on the mountain side, and glorious ocean views on the cliff side. More than 150 bird species have been observed along the trail since its opening in 2014, but there is the potential for many more as birders have access that wasn't possible prior to the construction of the tunnels.
The trail also offers some close-up examples of slope mitigation methods as well. A section of the cliff has been covered in a metal mesh to prevent boulders from injuring people. 

One might argue that this locality is not in the spirit of "The Other California", since it has been a famous section of Highway 1 for many decades, but it's only been the last few years that anyone could actually walk and study this fascinating spot, and only a relative few people know about the trail. If you visit the Bay Area it is well worth a visit.

But you might consider doing it soon! There is less stress on the slope from heavy traffic, but the fundamentals of the slide are still in place, and it can't be predicted when new damage might occur...

For the park brochure and trail map of the Devil's Slide Trail, use this link:

DSTrailBrochure-Nov2018-FINAL-web-formatted.pdf (

For a geology road trip along the coast south of San Francisco check out this link:

Microsoft Word - chapter8.doc (

For engineering details on the slide, check out the following USGS Bulletin:

USGS Bulletin 2188, chapter 7

For a geologic map that covers the slide area, check out:

Microsoft Word - smgeo.doc (

USGS Open-File Report 98-137

Wednesday, August 4, 2021

A Different Kind of "Other": Yosemite of the Pandemic

Half Dome from Sentinel Bridge
I've spent a fair amount of time writing about "The Other California", the spectacular places we have in our state that don't tend to show up on postcards. But sometimes there are decent reasons to visit the places that are on the postcards. This is especially true with Yosemite Valley and Yosemite National Park. There are few places on Earth as spectacular as the granite cliffs and towering waterfalls. But summer isn't that time. It's hot and dusty, the waterfalls are dry or nearly so, and the crowds and traffic are...simply awful. It's my least favorite time of year.

But sometimes events conspire. A pandemic continues to rage across the country in large part because a significant proportion of the population refuses to mask up or get a vaccination. As a result, the National Park Service instituted a reservation system at Yosemite National Park, limiting the number of daily visitors. And despite the desperately dry conditions caused by the intense drought, there were a number of monsoon-related thunderstorms in the High Sierra in the last few weeks. Mrs. Geotripper and I decided to give the valley a chance, so I carefully watched the reservation site ( and caught a cancellation. We headed up the hill on Monday. 

The view from Swinging Bridge of Yosemite Falls
It was a different world in Yosemite Valley. Two years ago we paid a visit on Labor Day weekend (our out-of-town visitors couldn't come any other time), and it was absolute mayhem. There was an hour-long wait at the entrance station, and a two-hour long traffic jam that resulted in a single parking spot for the day with no chance for exploration (the trams were stuck in traffic too). But Monday there was no waiting to get into the park, and there were parking spots available everywhere, even the ones usually most impacted, like Swinging Bridge, and Sentinel Bridge. The weather was warm, verging on hot, but the ground was moist, the meadows still green, and Yosemite Falls was flowing. It was the kind of day that every visitor to this beautiful place deserves, and it was the kind of day that had become exceedingly rare in recent years.

There is usually a gaggle of photographers standing on Sentinel Bridge (the top picture) because of the artful possibilities of catching the reflection of Half Dome on the Merced River. We had the bridge to ourselves. Swinging Bridge (which for the record does not swing) was crowded as always, but even there the bridge was empty for a few moments and I was able to score a shot of Yosemite Falls without the aforementioned crowds in the picture.

There are lesser-known viewpoints like the one above of the Cathedral Rocks and Cathedral Spires, and on most days the three parking spots are taken. But once again we had the pullout to ourselves, and got a wonderful view of these cliffs that would qualify for national park status in any other place, but which barely catch the attention of travelers on their way out of the valley.

Another crowded spot on a normal day is Valley View at the west end of the valley. The small parking lot is usually packed, but once again there were spots available. El Capitan (left) and the Cathedral Rocks and the wispy, nearly invisible Bridalveil Falls (right) reflected on a slow-moving stretch of the Merced River.

I was going to write about the need to come to Yosemite on a weekday if at all possible, but it occurs to me that a better discussion is whether to implement a reservation system permanently. The concessionaires and surrounding communities of course depend on as many visitors as possible to thrive and maintain their profit margins. But the quality of the experience of visitors is radically diminished when they spend most of their time waiting in lines and being jostled by crowds on the trams and the trails. People expect that sort of thing at an amusement park, but that's not what our national parks were meant to be. Consider the mission of the parks: to preserve unimpaired the natural and cultural resources and values of the National Park System for the enjoyment, education, and inspiration of this and future generations. That simply doesn't happen in our most popular parks like Yosemite, Zion, Arches, and others that are bursting at the seams with tourists.

Our park system has not expanded with our population, and the budget of the park service is cut seemingly every year. The last administration actually cut the size of a number of precious parks. We need to expand the opportunities of people to experience the parks in the best way possible.