Hike to oyster fossil field in California desert

The West Mesa Trail passes the full length of the Willis Palms.

Some 3.1 million years ago, the smoothound shark lived in the waters
covering the Coachella Valley.

West Mesa Trail topo map. Click for larger version

This article originally was written for and appeared on the Uken Report.

Day hikers can head to an oasis brimming with wildlife and fossils on the West Mesa Trail near Palm Desert.

The 2.2-mile lollipop trail sits at the base of Little San Bernardino Mountains in the Coachella Valley Preserve. It’s sometimes referred to as the Willis Palms and West Mesa Trail on maps and in other literature.

To reach the trailhead, from Interstate 10 take Ramon Road east at Thousand Palms. As approaching the foothills, turn left/north onto Thousand Palms Canyon Road. A parking lot is on the road’s left side in about 0.66 miles. The trail heads northwest from the lot along the base of the mountains.

Desert flowers
The trail’s opening section consists of loose sand, as the route heads through a wash. Be sure to wear quality hiking boots; a trekking pole also can help with stability.

In about a quarter mile, leave the trail’s stem for the loop. Go right/northeast around the base of the foothill in front of you. The trail gradually gains elevation.

At about 0.8 miles from the trailhead, you’ve reached the loop’s north side. The trail then heads up and crosses the foothill. Your reward for the exertion are great views of the Coachella Valley spreading before you (Thousand Palms and Palm Desert are directly ahead) with the Santa Rosa and San Jacinto Mountains rising above it.

At roughly a mile in, you’ll begin the descent down the foothill. If hiking a day or two after a rainfall in late winter or early spring, wildflower blooms usually can be spotted along the way. Chia, the desert gold poppy, desert sand verbena, dune evening primrose, and sand blazing star all grow in the area. Butterflies and the carpenter bee often flit about the blossoms.

Desert wildlife
Though appearing like wasteland, a number of creatures actually thrive near the wash and on the foothill. The lizard is ubiquitous with the zebra tailed, dune and leopard species, as well as chuckwallas, all common. Footprints of roadrunners, black-tailed jackrabbits, and coyotes usually grace part of the trail. If you’re really lucky, you may sight the paw prints of the rarely seen bobcat, desert kit fox, or raccoon.

Once at the foothill’s base, the trail turns southeast and quickly arrives at Willis Palms. The oasis of California fan palms stretches 1200 feet from northwest to southeast. It is one of several oasis that line the San Andreas Fault, which causes water from the valley’s aquifer to seep upward through cracks in the earth.

Willis Palms is a testament to nature’s resilience. A fire burned much of the grove in November 2010, but within weeks the flora already was growing back. Bats and birds lost their homes when the fire destroyed the palms’ skirts, but all have since returned.

Today, Willis Palms is a good spot for birdwatching. Cactus wrens, hummingbirds, mourning doves, and Gambel’s quail have been spotted there. Look up, and you may see an American kestrel, raven, red-tailed hawk, or even a great horned owl eyeing the ground for a meal.

Oyster fossil field
Sign of life from a long ago age also can be found at the oasis. Erosion has exposed an oyster fossil field formed when this part of the world was at the bottom of an ancient sea about 3.1 million to 3.2 million years ago. At that time, the Gulf of California extended into the Coachella Valley with the warm shallow waters running about 30 to 98 feet. Fossils for at least four kinds of sharks and rays as well as three kinds of fish also have been found around the oasis.

To locate the oyster fossil fields, look for large white patches as the ground rises off the desert floor beneath the fan palms. Oyster shells stick out of the fairly soft rock. Only take pictures, though – collection of the ancient marine fossils is illegal.

Around 1.9 miles in, you’ll reach the stem trail. Continue straight/southeast to the parking lot.

The West Mesa is not the best-marked trail and there are crossing routes, so be sure to carry a map and compass. Almost all of the trail is exposed to the sun and wind, so always don sunscreen, sunglasses and a sunhat. To avoid the desert heat, the trail is best done October through March; the preserve is open 7 a.m. to 5 p.m. during those months.

Cali trail heads past master of camouflage

Among the highlights of the Indian Palms Trail is spotting the threatened
flat-tailed horned lizard.

Indian Palms Trail map. Click for larger version.

Day hikers at California's Coachella Valley Preserve can encounter a lizard whose camouflage is so good that it has virtually no shadow.

The 1.6-miles round-trip Indian Palms Trail also heads to two small oases. From June through September, the 17,000-acre preserve is open from 6 a.m. to 8 p.m. then in winter from 8 a.m. to 4 p.m. Wednesday through Sunday.

To reach the trailhead, take Interstate 10 to Thousand Palms and exit onto East Ramon Road. Go east on it. Next, turn left/north onto Thousand Palms Canyon Road. A parking lot is on the road's left/southwest side; this serves the McCallum Trailhead with Indio Hills Palms and the Center for Natural Lands Management located there. Take the trail heading southeast toward the Pushawalla Palms Trailhead.

To the trail's south is Squaw Hill, which rises about 70 feet. Another path heads to its top, which gives a great view of the valley's western side.

Upon reaching the highway, cross it to the trailhead sign. The stone-sided trail begins by entering a wash. Floods in autumn 2018 covered the wash, but the trail since has been repaired.

Flat-tailed horned lizard
While the preserve is more known for the endangered Coachella Valley fringe-toed lizard, plenty of other reptiles live there. Among them is the camouflage master flat-tailed horned lizard.

Found only in southeastern California, southwestern Arizona, Sonora, and Baja California Norte, the lizard has a round, flat body with a dark vertebral stripe and a broad, flat tail. Long spines sit on its head. The lizard’s color changes to match the local sand, so the Coachella Valley's denizens tend to be whiter than its counterparts. The Coachella Valley marks the northern margin of the species’ range.

The flat-tailed horned lizard mainly eats ants though sometimes it will dine on beetles and other bugs. As standing water is rare in the preserve and other locations that the lizard lives, it acquires most of its water when eating.

In short order, the trail splits. Each way takes you to a desert oases to either the north or south.

Go left to the northern grove. The trail heads up a slight slope and then loops around a small group of California fan palms. Water seeping up through faults in the area helps water the palms.

Saltbush
Among the rocks only a few feet from the oasis are barrel cactus, creosote bushes, and sandpaper plants.

Another plant you'll pass along the way is four-wing saltbush. Slow down when you do, as these plants mark the best places to spot the flat-tailed horned lizard. As the saltbush produces fruit even during droughts, they naturally attract large ant populations, which in turn draws the flat-tailed horned lizard.

Four-wing saltbush is a type of evergreen shrub. They usually grow 2-4 feet high with thin leaves about 0.5-2 inches long. Their fruit is what really makes them stand out, though. The fruit has four wings at right angles to one another. The wings are densely packed on long stems.

Finding the flat-tailed horned lizard will be tougher than you think. As the sides of their flat bodies thin to an edge and they press their bodies to the ground, there's no shadow to make them stand out. The fringed scales on their sides further obscure them by helping them blend into the sand.

South grove
After looping around the grove, head to back to the junction and then go to the south grove. Though smaller than the northern oases, usually puddles of water can be spotted.

The flat-tailed horned lizard faces a number of threats. Kestrels and shrikes will hunt them, so their populations tend to be low with 0.1 miles of roads, which provide open ground and poles and power lines for the birds to perch. In addition, Russian thistle and Sahara mustard can limit movement of the lizards, which tend to be wide-bodied. Further, populations are becoming fragmented, reducing breeding populations. In the Coachella Valley, Interstate 10, the Coachella Canal, and other small roads effectively divide up the lizards' habitat.

After taking in the south grove, return to the junction and retrace your steps to the parking lot.

Avoid this trail during summer or anytime temperatures are in the 80s or higher. Always don sunscreen, sunglasses and a sunhat, as there is no shade on the trail. Pets are not allowed in the preserve.