Oyster Shell Beds, Yuha Geoglyph and Yuha Well
by L. Bremner – DesertRoadTRIPPIN.com
The Yuha Basin road trip was a trip I took back in March ’97. I haven’t been back to this particular spot since then, but I thought it would be a fun road trip to feature since I don’t have any new trips planned into this area until the fall, when temperatures cool down a bit.
There are newer GPS systems (hand held) that were not available in ’97. I’m sure a handheld gps system will work just as well as the one we used on a laptop. When we took this trip we did not have the BLM access map of the area. Make sure you pick one up as their access guide/map works with the numbered markers that are found throughout the Yuha Basin. It will make finding the Oyster Shell Beds much easier as there are many unmarked trails and roads in this area. See the BLM notes at the end of this article for more details on the area and maps available.
March 1997: In March, when the Sonoran Desert is hot, but not scorching, I took a day trip to the Yuha Basin in search of ancient fossils. The fossils are located at a point of interested called the oyster shell beds in the Yuha Basin.
The Yuha Basin lies in Imperial County on both sides of Interstate 8, approximately 100 miles east of San Diego, California. It can be accessed at the Dunaway Road Exit, which is also called the Dunaway Staging Area for Limited Use Off-Highway Vehicle (OHV) Recreation, about 10 miles west of El Centro, California.
I was accompanied by DesertUSA’s Publisher, Jim Bremner, my official off-road driver and technical expert. We were testing our new Global Positioning System (GPS) that we brought along to field test that same day.
By the time we arrived at the Dunaway Road Exit at 10:00 am, the temperature had already reached 98 degrees F. Dunaway Road is only paved for a few hundred yards on the south side of the freeway before it ends at the main entrance to the Yuha Basin.
Equipped with a Gem Trail Guide, several area maps and a portable computer loaded with Tripmate, a GPS application from DeLorme, we were ready to begin our journey into the Yuha Basin. Our destination was the Shell Beds, where 6 million-year-old oyster shell fossils and concretions can be found. The Gem Guide can be purchased in DesertUSA’s online store.
The Gem Trail Guide map shows a series of dirt roads with mile markers and washes as landmarks. Since there were a number of dirt roads leading from the end of Dunaway Road, it wasn’t clear which one we should take. After analyzing the Gem Trail Map, we decided to take the road to the right that headed southwest.
According to the map, we needed to travel 1.6 miles before we would turn left on another road. We had only traveled about .5 mile when our road seemed to disappear into a maze of trails (New Rules). Totally confused, we decided it was time to start up our portable computer and use our GPS system to show where we were and which direction we needed to go to reach the shell beds.
With the GPS locator on the dashboard, we asked Tripmate to locate our current position. In less than a minute, the screen displayed a map of the Yuha Basin with a green arrow pointing to our exact location (within 100 yards). The Tripmate maps are very detailed and, to my surprise, contained the location of the fossil shell beds as well. On the BLM map the oyster shell beds are located Along BLM Route EC346 and nearby side routes.
I sat in the passenger seat with the computer on my lap and navigated, as we slowly maneuvered our 4WD Jeep Cherokee across the rough terrain. There were times when the road would disappear or we would reach an area that was too difficult to traverse in a Jeep. We would then backtrack to a different trail. I had to get out of the Jeep several times to see if we could make it down some of the hills, many of which we did not want to risk, so we took alternate routes. As we drove, the GPS system tracked our exact position and left a trail of green arrows across the screen indicating the route we had traveled.
Within 30 minutes, we reached the edge of the fossil shell beds and parked in a dry wash to explore the area. As I looked out the window, I spotted a Desert Iguana basking in the sun next to an oyster shell fossil. I quickly grabbed our video camera and captured some footage of the Iguana before it scurried off into the nearby brush.
As we began to explore the area, I noticed the ground of the dry wash was littered with oyster shell fossils. The walls of the wash were formed in layers, and you can clearly see where the shells once covered the basin floor. The oyster shell fossils are remnants of Lake Leconte, which covered most of Imperial and central Riverside counties about 6 million years ago.
We collected a few samples of oyster shell fossils and some rocks with shells embedded in them. As I scanned the area, I found an interesting white- colored crystal specimen in the sandy wash. Later, I was able to identify the sample as a selenite crystal, which can be found in the soft sand and soil areas of the Yuha Basin. These crystals are fragile and need to be handled carefully.
If you are an avid rockhounder, you can search the area for Gypsum, which is commonly found in the shell bed area. Agate jasper and obsidian can also be found closer to the Dunaway Road Exit, approximately 2.5 miles southwest of the basin entrance.
It’s hard to believe the bleached desert flats of the Yuha Basin were once covered with lush vegetation, vast lakes and numerous Indian encampments. The fossils, geoglyphs, and other evidence left behind, are the only clues we have to tell a story that spans millions of years.
Today, the Yuha Basin is home to many animal and plant species which have adapted to its harsh environment. The BLM has designated 40,622 acres of the Yuha Basin as an Area of Critical Environmental Concern (ACEC). The purpose of the ACEC is to protect sensitive natural and cultural resources while providing for a wide range of uses.
After leaving the shell beds, we continued our exploration of the Yuha Basin, heading northwest. We slowly worked our way through the maze of trails as we searched for a more direct route to Route 98, which would take us back to Interstate 8 and the small town of Ocotillo.
In our travels we came upon a fenced-in area that looked like some sort of landmark. As we approached the fence, we spotted a sign that told us the site was the Yuha Geoglyph, which was constructed by prehistoric Native Americans. A geoglyph is a large symbol etched into the ground by clearing lines in the surface layer of small, dark rocks (known as desert pavement) to expose the lighter soil underneath.
Since we were level with the site, we were unable to appreciate the geoglyph images, but the landmark did show an aerial picture of the geoglyph. In 1975, the geoglyph was damaged by vandals and has since been reconstructed by the Imperial Valley College Barker Museum and BLM.
Not far from the Yuha Geoglyph is another historic landmark, Yuha Well. Although we didn’t get a chance to visit the well, the BLM offers an Access Guide that provides the following information.
Located on BLM Route EC346, the Yuha Well became an important oasis for later travelers and settlers following the de Anza Trail through the desert. Led by Indian guides, Captain Juan Bautista de Anza was the first Spanish explorer to visit the Yuha. Some 200 years ago, his party replenished their water supplies here before pushing on. Their goal was to establish a trade route between Arizona, the Pacific Coast, and the mission in San Francisco. See “Exploring the Yuha Desert”, a joint BLM/National Park Service pamphlet, 2004.
Notes: 4WD is STRONGLY recommended. While driving the numerous trails and roads in the Yuha Basin, you will see various numbered markers throughout the area. These markers are maintained by the BLM and correspond to a route map called the “Imperial Valley South Desert Access Guide #22.” The BLM produces a series of Access Guides for most of the areas it manages. The Access Guides can be purchased from the BLM or related ranger stations.
Info. From the BLM Site
Unrestricted off-road vehicle use and camping has greatly affected the Yuha Desert. In 2003, the Bureau of Land Management (BLM) issued special policies and regulations to help protect the Yuha from impacts from unrestricted activities. Complying with these rules will help protect the desert.
Vehicles can travel in the Yuha only on marked BLM designated routes. Route 346 (California Backcountry Discovery Trail), Route 274, and Route 308 (Anza Trail) are open to all vehicles. All other designated routes are limited to street legal vehicles.
Camping in the Yuha is limited to designated camping areas. Refer to the map on the reverse for the location of four of the designated six campgrounds within this area. Overnight unoccupied vehicles are limited to the area adjacent to the Jacumba Wilderness Area for overnight backpackers.
All Native American sites and artifacts are part of our shared cultural heritage and protected by federal law. Report any looting immediately to the BLM.
Visitors may collect up to five gallons of fossilized invertebrate. Commercial collectors must obtain a collection permit.
Source: BLM Site
For all of its beauty, the Yuha Desert can be unforgiving for those unprepared. Always carry at least one gallon of water per person. Be prepared to take care of yourself. If you break down, seek shade near your vehicle so that others may easily find you. Smuggling activity occurs regularly near the international border. Use good judgement. Do not attempt to cross the international border except at a designated Port of Entry. Assist other travelers in need. Call 911 for help. Cell phone coverage is not complete in this area – change locations to get better reception.
BLM Contact Information
The Yuha Desert is administered by the El Centro Office of the Bureau
of Land Management. 1661 South Fourth Street, El Centro, CA 92243,
(760) 337-4400. Contact the visitor center during normal business
hours for more information. The Juan Bautista de Anza Trail is
administered by the National Park Service, 1111 Jackson, Oakland, CA
94607, (510) 817-1438. Contact that office or the BLM El Centro Office
for additional information about the trail.
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