Six million years ago California’s inland deserts would not be recognizable as we know them today. The desert, which at first glance appears to be a barren wasteland, was not too long ago a tropical sea full of marine life. While hiking in the Domelands of Anza Borrego, you don’t have to look far to find irrefutable evidence that supports this.
As I planted my shoes on the flaky sediment formations in the Coyote Mountains, surrounded by thousands, perhaps millions, of sea fossils, I imagined standing on the ocean floor, peering up to the sun on the surface.
The fossilized sand dollars, sea snails, and coral that litter the ground in every which direction tells a story of a sea that once shape the land around me. These creatures, that hopefully lived prosperous lives, eventually died, sinking to the ocean floor where they were buried by sediment. That ocean floor now sits 1,500 feet above the sea and the elements have torn back the layers of time to expose a snapshot of Earth’s history when these marine creatures were flourishing.
Six million years ago, way back when tectonic forces were beginning to pry the Baja peninsula away from mainland Mexico, a warm, shallow sea covered the land that is today the bone-dry desert of Anza Borrego. This sea flourished for ages, evidenced by the fossils of whales, walruses, pelicans, turtles, and abalone that have been found in these mountains. Then, about 4.2 million years ago the oceans began to recede. Tectonic activity ensued, uplifting the area thousands of feet. To top it all off, after the last ice age, about 8,000 years ago, the climate drastically changed and the dry desert that we know today took form.
The desert, which at first glance appears to be a barren wasteland, was not too long ago a tropical sea full of marine life.
This area of the Coyote Mountains in Anza Borrego, coined the ‘Domelands’ (I presume for the shape of the sandstone), caught my attention for a number of reasons. In a relatively small area you can find sandstone caves shaped by wind, slot canyons, sweeping views, and of course, a mind boggling amount of fossils just sitting on the ground.
I had been dying to break in my new down sleeping bag in some cold weather, so I figured a winter night out in the Domelands would be a perfect inauguration.
Part I: Heading out to the Domelands
I opted to complete an 8-mile loop in the Domelands and then top it off with a freestyle search for a nice, secluded camping spot, returning to my car in the morning to head back to San Diego.
I drew up a map with labels below for those that are interested in following the hike as they read, or perhaps doing it on their own.

Green line – Loop trail (completed clockwise)
Purple line – Searching for a campsite
A – Trailhead / parked car
B – Wind caves
C – Slot canyon
D – Campsite
E – Sunrise
I took my time leaving my house in San Diego to make the 100-mile drive out to Anza Borrego. The nine miles that I had planned for the day were relatively easy, so I didn’t want to finish my route so quick that I would be sitting around twiddling my thumbs.
Luckily, my roommate Nate let me borrow his SUV with sufficient clearance for dirt roads. My little Nissan probably would have had trouble making it over a few of the bumps on the road out to the trailhead.
I breezed through the 1.5 hour drive from San Diego to Anza Borrego, pulling up to the parking lot at the Domelands to find that the trail was quite a bit more popular than I had imagined.
The ‘parking lot’ was nearly full and a group of about fifteen people were huddled around preparing for a hike. They were all playing the name game, some talking about their past backpacking experience, while others discussed how excited they were to do their first trip. It was clear who the group leader was by his confident, instructional tone. It seemed that it was a hiking club or something that meets on the weekends.
Now, I didn’t exactly drive out to the middle of the desert by myself to hike in a group of fifteen, so I let them get a 10-minute head start on me on the trail, thinking that they could put a good amount of distance between us.
When I calculated that the coast was clear, I threw on my pack and began my hike up into the Coyote Mountains. Unsure of how easy the trail would be to follow since there are no markers, I had done a lot of research on the route to take, so much in fact that I felt like I had already memorized the curves of the desert washes that lay around each corner on the trail.
After about five minutes of hiking I turned a corner to discover that the group of fifteen hadn’t gotten very far. Nothing happens fast in a group. In this case, a few of their group decided that they had overdressed and wanted to shed a layer, which gave me a chance to shoot on ahead.
I smiled as I passed, said hello, and left them in the rear view mirror. Every time I looked back, they were nowhere to be seen. I wouldn’t have lasted long in a group walking at that pace.








Part II: Wind caves
A few miles into the hike the trail ascends out of a wash and up into the mountains (you could call them large hills).
In this section of the Domelands the sandstone sediments emerge from the sedimentary layers with interesting rock formations called wind caves. A wind cave is pretty much what it sounds like, a cave that has been formed through the erosion of wind over many thousands of years.
Sandstone is a unique rock that is durable, and resistant to erosion. As a result, sandstone often forms dramatic cliffs, natural arches, or caves such as these. I’d put sandstone as #2 on my list of favorite rocks, probably after granite, I suppose.
I found a small overlook rock to survey the wind caves, picking out the ones that looked best to visit.





Part III: A sea of fossils
As I was walking around checking out the different wind cave formations, I was too focused on looking ahead to the next cave to notice what lay right before my eyes. I was walking on an ancient seabed that clearly had been teeming with life at one point. Thousands of shells, sand dollars, and sea snails were strewn on the ground. In fact, they were so abundant that they were hiding in plain sight.
I had been passively looking for fossils for the first hour or so on the hike and hadn’t noticed anything, but when you arrive to the wind caves, you can’t miss them.
In no hurry to get on my way, I took about a 45 minute break poking around the fossils, documenting all the different types I could find.
Thousands of shells, sand dollars, and sea snails were strewn on the ground.





Part IV: Squeezing through the slot canyon
After I had seen each type of fossil several dozen times, I continued down the trail to my next destination, a tight slot canyon that would mark the half way point of my loop hike.
I was happy to see that the trail was very easy to follow because google maps and some stories online had cast some doubt on how easy it would be to find my way.
I wanted to be extra sure that I was keeping on track and not heading astray because just four miles (as the crow flies) to the north lies a mysterious no-man’s land called the Carrizo Impact Area.
The Carrizo Impact Area is a 45-square mile chunk of Anza Borrego that was used as a bombing range during World War II and the Korean War. Apparently the desert is sprinkled with exploded and unexploded ammunitions, complete with 1,000-pound bombs, rockets, and 50-cal bullets.
I steered clear of that area, not wanting any thousand-pound bombs to put a damper on my backpacking trip.
Somehow I had never heard about this place, even though I had done numerous hikes in the vicinity before. My fascination with the off-limits area grew as I researched online and discovered that there surprisingly is very little information available. I also couldn’t find any good map that clearly defines the borders of the area. From what I understand, there are people tasked with carefully disposing of bombs that are reported. They tend not to report the location of the bombs for fear that it will cause people to go looking for more.
Anyway, the important part is that I was aware of the existence of the Carrizo Impact Area and that, if for some reason, I started wandering north that I was not to cross a certain wash that has large, six-foot do not enter signs. I steered clear of that area, not wanting any thousand-pound bombs to put a damper on my backpacking trip.


































Part V: Closing
To the outsider backpacking trips can seem like a big undertaking, but once you have all the gear and a destination close to home, you can really get the full experience with limited time. I was back at my car by 8am, less than 24 hours after leaving San Diego. A quick strike mission to the desert.
The southern portion of Anza Borrego had never really caught my attention before, for some reason. The impressive peaks and valleys tend to be more to the north, closer to Borrego Springs, but this trip gave me a new perspective on the cool places to visit in the park.
I was quite satisfied with my less-than-24-hour trip, having explored wind caves, squeezed through an impressive slot canyon, and examined hundreds of fossils.
I’m heading back out this way soon to search for some Native American pictographs, inspired by a conversation that I had with another hiker on the trail. Stay tuned for more on that.
I appreciate all your info here! I’ve taken my family to the Domelands several times, but I think my favorite visit was when I took friends from New Hampshire who’d never been to a desert before! We made it a whole “sand to snow adventure” by heading up S-2 to the 78 west into Julian, then back south along Sunrise Highway, stopping for the view and a snowball fight at the Desert View Picnic Area. 🙂 Anyway, I’ve wanted to continue to the slot canyons but haven’t been able to find the trail after the last few wind caves, so I’m appreciating your detailed descriptions and map. One note: the Domelands aren’t in Anza-Borrego Desert State Park, but just barely. If you look at the map at https://www.parks.ca.gov/pages/638/files/abdsp_Park_Map201704.pdf you’ll see that the ABDSP border is west and north of the Domelands. The only reason I point it out is because like most CA state parks, ABDSP doesn’t allow dogs on trails, but BLM land is pet-friendly and we like to take our dogs hiking with us if possible (we follow rules & regulations about where they’re allowed, along with abiding by leash laws & cleaning up after them). Thanks again for this great post!
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Hey Leslie thanks for reading. The Domelands are a great intro to the desert as they have a wide variety of points of interest. And yes I know it’s outside of the state park but it’s so close I just lump it in there. Hard to miss the fact you’ve stepped onto BLM land when you see all the shooting trash at the trailhead
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Hi Even,
I randomly stumbled across your post and really enjoyed it. I’ve done that Domelands loop several times and it never gets old. With the San Diego hiking club– uh oh, a big group, but knowledgeable and a lot less officious than the Sierra Club. That steep 30′ dropoff goes into Andrade Canyon. It’s a tough downclimb but a relatively easy upclimb if you have a bit of experience with that sort of thing. I’ve often intended to climb that hilltop where you went for the sunrise but never got around to it. To the East of that hill is a tributary canyon to Andrade. Some cool scenery in it, and some mildly dicey spots. It makes a nice loop so you can do that drop at the top of Andrade as an upclimb. I’ve been a mile or so into the Carrizo Impact Area by accident– with a club group in tow (oops!). It’s downstream a little way from where that side canyon meets Andrade. The first time I was there, there was an obvious fence. But when I led it a year or two later… Gee, I thought that fence was closer… Apparently a flood had taken it out. We did notice some mangled barbed wire on the way back. One more tidbit. If you climb over the canyon wall to the East of that side canyon and poke around toward the north, you’ll find a very long slot canyon. It’s gets seriously rugged over there though, with a lot of crumbly stuff. Well, enough rambling.
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Hi Richard, thanks for reading and sharing your knowledge of the area. Careful wandering into the Carrizo Impact Area! Happy hiking.
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I really enjoyed reading your description of the Domelands area. I have been there twice already with backpacking groups, and now I will be leading with my daughter for a long day hike through the loop. So much to see and appreciate in that super cool nook of the world. Nice job!
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Very nicely written, photographed and documented hike.
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Thanks for reading, Phil.
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I always thought Anza Borrego was a magical place but had no idea so many sea life fossils could still be found. It seems it is difficult to find solitude anywhere in a state with so many mega metropolises even in a remote desert but glad you at least got some dark skies.
Thanks for taking me to a place i likely could not reach on my own.
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Hi Shelley, San Diego is just a short hop over the mountains to find solitude. I actually just went back today to go petroglyph hunting. I’ll share those photos too.
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Regarding the un-identified desert fossils…it could very well be a Chambered Nautilus fossil. At one point while hiking down a slot canyon to get back to the river, on a trail accessible only from the river (while rafting down the Colorado River through The Grand Canyon), I noticed a18-inch long, segmented shell fossil, tapered from 5 inches wide at one end and narrowing to a defined point at the other end, standing out in bas-relief from the stone floor I was resting on, one I couldn’t identify. Another hiker in our group said it was an Chambered Nautilus, fossilized eons before these sea-crawlers had curled-up their segmented shells into the curved-inward shell-shape we find today swimming in the oceans. Or perhaps not.
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I see my car and then my tent in the wash you were admiring. It was a perfect desert weekend. The two groups you passed were Sierra Club Wilderness Basics Course groups.
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Hi Renee, thanks for the info!
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In a way, Evan, I think this is your best column: You express more of your own insights and ideas here than in most prior columns; and I think you have provided your readers with serious and important information they’ll need if they decide to take the same trip. You mention distance from San Diego, the length of the hike, info on campsites and parking and equipment that will help any such readers who want to follow in your footsteps.Your writing is clear and colorful and I particularly enjoyed your subtle criticisms of the group of hikers you encountered on the hike. Also, you wrote, ” I was too focused on looking ahead to the next cave to notice what lay right before my eyes,” I think you’ll find (but I think you have already discovered) that the same holds true for life in general. Good work!
-Lee
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The previous comment should not read that it’s from “Anonymous.” It is, obviously, from your Uncle Lee!
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Hi Lee. Seems like you enjoy every post more than the last ha. Thanks for the comment.
And there’s nothing wrong with hiking in a group! Just not what I was going for this weekend.
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Really nice post! Enjoyed reading it.
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