Nature Notes: The Clayton’s Overlook Exhibit: A Key to Davis Mountains Geology, History

Lava surged and surged again, in vast flows hundreds of feet thick. Eruptions spewed ash and lava. Magma pooled beneath the Earth.

Weathered over millions of years, the products of that fiery activity are sublime today. That volcanic chapter is visible from Alpine and Fort Davis to Balmorhea, in the landscapes of the Davis Mountains.

At the Chihuahuan Desert Nature Center, a unique exhibit offers a key to this geologic history. But the exhibit, on the hill called Clayton’s Overlook, named for CDRI donor Clayton Williams, has a broader purpose as well – to show how geology shapes the human experience.

Founded in 1974, the Chihuahuan Desert Research Institute, or CDRI, is one of the region’s flagship educational institutions. The nonprofit works to promote appreciation of the region’s natural diversity.

In the early 2000s, geologist Blaine Hall was working closely with the CDRI. A West Texas native, Hall’s geology career had taken him around the world. But he’d retired from industry and returned here, and was teaching at Sul Ross State University.

One day in 2002, Hall climbed Clayton’s Overlook, an outcrop on the CDRI’s Nature Center property south of Fort Davis. In the panoramic view, Hall saw the highlights of Davis Mountains geology. And he saw an educational opportunity.

“What really struck me was that, since I had this 360-degree view, it was incumbent on me to figure out how to utilize it, to be able to share it with other people,” Hall said. “That sounds pretentious, but that was really what my thought process was.”

What does the view disclose?

Trans-Pecos Texas once witnessed powerful volcanic activity. The Davis Mountains are the result of very extensive lava flows of that volcanic history.

Over a 3-million-year period, beginning 38.4 million years ago, molten rock poured from multiple fissures in present-day Jeff Davis and Brewster counties. The largest flows covered as much as 1,000 square miles.

The flows ceased, but 2-and-a-half million years later, magma again began to press upward. This time, it didn’t reach the surface. It intruded into and domed up the rocks created by the earlier lava flows.

At Clayton’s Overlook, Hall saw distinct strata formed by different flows. In three mountains, the Pollard, Barillos and Musquiz domes, intrusions had raised and exposed the volcanic timeline.

Hall began to consider an interpretive exhibit. On a subsequent visit, he brought a ladder. He climbed a few rungs – and found the elevation made a difference.

“All of a sudden what you felt was you were part of what you were looking at,” Hall said. “That was a kind of a major breakthrough in the design of what we were going to build.”

Hall and Alpine architect Tom Greenwood designed a raised, octagonal platform. The 360-degree panorama would be divided into eight views, with panels to interpret the landscape.

CDRI’s then-executive director, Cathryn Hoyt, provided critical help in writing text and taking photos for the panels. The text is written for an eighth-grade reading level. Rendering the complex science accessible for young students was a major challenge for both Hoyt and Hall.

Fort Davis was built to safeguard the San Antonio-El Paso Road, which conveyed 49ers to California. The road followed springs that flowed from volcanic rock. The fort was placed for access to water and timber. From the overlook, one can see how geology dictated these foundations of the Fort Davis community.

As a ranching hub, Fort Davis relies on lush surrounding grasslands. These higher-elevation grasslands, in turn, exist because of rich volcanic sediments.

The exhibit was a complex undertaking. Foundations, corporations and individuals donated to the project. CDRI hired pack teams to haul exhibit materials, including the panels, to the hilltop. The exhibit opened in 2009. It’s unique not only in the region, but nationally.

Science education relies increasingly on digital media. Here, visitors learn about geology – in the midst of the landscape itself.

Hall said he hopes the exhibit provides visitors with new tools for looking at the world.

“What we hoped was that people would take away a way of looking at other things,” he said, “and start to appreciate and recognize that they could also understand, to a degree, what they were seeing somewhere else. In other words, this way of looking and thinking was exportable.”

The Davis Mountains region is among the most scenic in Texas. At Clayton’s Overlook, visitors learn the secrets of this stunning landscape.

Nature Notes is underwritten by the Dixon Water Foundation and is produced by Marfa Public Radio in cooperation with the Sibley Nature Center. This episode was written by Andrew Stuart.

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