Set your watches to the Permian Period (that’s 280 million years ago!), when prehistoric beasts ruled the Earth. Just a short distance northwest of Las Cruces, experience the 5,255-acre Prehistoric Trackways National Monument.
Written and Photography by Victor Gibbs
The Prehistoric Trackways National Monument was established in March 2009 by the Bureau of Land Management. There are currently no established facilities at the monument, though some interpretive signs at the parking areas will help get you oriented. New features within the park are being built as funding become available.
Well-known for their fossil richness, the red siltstone canyons of the Robledo Mountains boast several dozen prehistoric trackways. Batrachichnus tracks are the most common vertebrate species found in the area. Similar to a salamander, the Batrachichnus’s track is similar in size to a human baby’s handprint. There are also marine invertebrate fossils in the park, including Bivalves, Gastropods, Brachiopods, and Cephalopods.
In 1987, amateur paleontologist Jerry MacDonald discovered one of the most extensive sets of Dimetrodon tracks ever found. Dimetrodon was a mammal-like reptile, so named because it had five toes and the head of a mammal. The creature had a sail-like fin on its back, so it could regulate its temperature. Over 50 of this monster’s prints were found, along with several other species of prehistoric beasts and plant life at what is known as the Discovery Site. The tracks were laid down in a red mud on an ancient seashore. This kind of fossil is called a trace fossil, or ichnofossil. Over millions of years of pressure, the tracks formed into five- to seven- inch thick siltstone plates.
Under guidance from the Bureau of Land Management, 2,500 siltstone plates were carefully removed by hand and carried out using a special backpack. During the excavation of three long dinosaur trackways, each plate was catalogued and numbered for later reassembly. The plates are now housed at the New Mexico Museum of Natural History and Science in Albuquerque. Tracks and imprints of vegetation can be seen eroding from the Discovery Site and other locations in the Robledo Mountains.
Make a little time for exploration while in the park. You may make a significant discovery of your own. Please keep in mind that this is a national monument. Take nothing but pictures, leave nothing but your footprints in the sand. Who knows? Maybe some future paleontologist will find them in 280 million years.
What to Bring
Make sure you bring plenty of water (at least four liters per person in summer months), snacks, a first aid kit, and protection from the sun. In the summer, try to leave early in the morning to beat the heat. As this area is a little off the beaten track, let someone know where you are going. And always beware of rattlesnakes! Getting There
Getting to the trackways at the Discovery Site is a little tricky, requiring an approximately three mile round trip hike through some of the best country the Robledo Mountains have to offer. If you don’t want to walk that far, this area has a lot of other good hiking locales.
From the intersection of Picacho/US Highway 70 and Valley Drive, travel 5.5 miles north on Valley Drive to Shalem Colony Trail. Turn left on Shalem Colony Trail, and travel 1.3 miles through the pecan orchards. Just after you cross the Rio Grande, take a right onto Rocky Acres Trail. Follow Rocky Acres Trail for approximately 0.2 mile, then turn left onto an improved gravel road. Just a short distance up this road is the Bureau of Land Management parking area for the monument containing interpretive signs. Your hike begins here.
The Ridgeline Trail
A sign for the Ridgeline Trail is on the north side of the parking lot. Brown trail markers will help guide you along the way. The trail to the Discovery Site extends across a small arroyo and follows the course of an abandoned two-track up and to the west. This route has an elevation gain of 750 feet over 1.45 miles (one way). Along this route, you’ll be treated to spectacular views of the Mesilla Valley and the Robledo Mountains. The high road slopes up for the first 0.6 mile, then winds around one black hill and then over another black hill. After the second black hill, look for a trail leading down into the canyon below.
Follow the trail down the canyon for another 0.2 mile to a red siltstone slope on the right side of the canyon. There is a large brown Bureau of Land Management interpretive sign on the opposite side of the canyon to help orient you. If you have a GPS, the latitude/longitude coordinates for the Discovery Site are: North 32° 22.849’, West 106° 52.902’.
The Return Trek
Once you have explored the Discovery Site, you can either return along the Ridgeline Trail, or you could continue down the canyon back to the parking area. This route is a little trickier, more interesting, and is downhill all the way. This return route is about 1.3 miles in length. Much of the canyon doesn’t have a trail marked path, as the canyon floor is solid limestone. A variety of fossils are embedded in the limestone and there is also a greater plant diversity in the canyon than the ridge, including sotol, juniper, and prickly pear cactus.
About a third of the way down the canyon, you will see an old rock quarry on your right. The Bureau of Land Management has placed yellow warning signs to keep people clear of this hazardous area. Keep heading downstream in the canyon and to left of the tailing piles. As the canyon empties into a wide arroyo, you will soon be back at the parking area.