DON'T TAKE IT FOR GRANITE

I wanted to see the Surprise Canyon Formation. I wanted to understand how it was possible to discover a new formation among the layers of rocks in the Grand Canyon - some of which have been there for almost 2 billion years. In a June 2019 lecture, part of a series marking Grand Canyon National Park's centennial, at Northern Arizona University's Cline Library, geologists George Billingsley and Peter Huntoon discussed mapping the geology of the Canyon. It was Billingsley who discovered this new formation. It happened at river Mile 274 on a June 1972 trip down the Colorado River. Looking up, Billingsley noticed a rock ledge unlike the rock below or above it. Exploring further once he was off the river, he found a layer of rock that had formed in ancient valleys and karst caves eroded into the top half of the Redwall Limestone. The formation's thickness essentially corresponds to the depth of the valleys in which it was deposited: It averages approximately 400 feet thick in the western half of the map area, and it thins to about 30 feet in the eastern half. Existing in a non-continuous line throughout the length of the park and farther east, it is a kind of interruption in the neat order of things, as if the Earth itself refuses to be typecast. Plant and bone fossils, mud cracks and ripple marks make the Surprise Canyon Formation the most fossiliferous rock unit in the Grand Canyon. This discovery did not change the Canyon's walls, but it does change our understanding of how those walls were built, forcing us to acknowledge that even in stone, nothing is written in stone. Billingsley named the rock layer after a lightly visited canyon, in the western end of the park, whose name had not yet been given to any other formation. (Surprise Canyon itself is a difficult hike with little water.) Fascinated by the idea of a new formation that is about 310 million years old, I decided a trip to the Canyon was in order.

Billingsley had already told me the formation was hard to see, that much of his own viewing was via helicopter, that it wasn't near anything easy to reach, with the exception of a spot near the 3-mile point along Bright Angel Trail. (I have since learned that it is also visible along the South Rim's more difficult New Hance and Grandview trails, but I've not hiked either.) By walking up from Three-Mile Resthouse, which sits on Redwall Limestone, and turning the corner to the east, behind it, to face another wall of Redwall Limestone, I expected to see it.

I had studied the geological map. I knew I could identify it.

I was able to identify a condor. Some prickly pears. An isolated moment of silence just off the busiest trail in the park. Scrutinizing the wall ahead of me, I identified nothing.

The Surprise Canyon Formation is very clear on the geological map of the Grand Canyon. There appear to be views of it on Pattie Butte from Yaki Point; views of it on several buttes from Shoshone Point; and a few other places where good binoculars or a telephoto lens should bring it into focus. The geological map, authored by Billingsley and published by the U.S. Geological Survey, covers a 58-by-42-inch piece of paper. It is gorgeous work. One of the pleasures of this map is the experience of color it offers. Meticulously drawn and colored, when not being read as geology, it becomes a kind of abstraction, a piece of art.

Color, of course, contributes to the awe one experiences on viewing the Grand Canyon. It is part of what makes the Canyon so frequent a subject for painters and photographers, for whom every color-changing nuance - the angle of the sun, the presence of clouds, of storms, of seasons - is cause for yet another painting, another photograph. In the Canyon, color becomes a measure of time, the face of geology.

In fact, color is a geological event. The age, the particular rock, the minerals in the rock all contribute. If you're floating the river, you have a particular point of view of formations and color; from either rim, another; from a walk down into and out of the Canyon, the most intimate view, the view you can touch, the view you feel as you walk, the view that, in its intensity, becomes your world.

Somehow, I had expected the map to translate to my view. Returning to the resthouse, I had a drink, a lunch, a fury I was not about to let anybody else see, and started back up the trail to the South Rim. It was later than it should have been. (It is always later than it should be.) But the hour allowed me, at dusk, to pass a group of men from Spain returning from their camp at the bottom. "We're waiting for the stars," one told me. Once the stars were out, they passed me. And I had the magnificence of starlight and the Bright Angel Trail to myself to end the day.

All hiking or climbing is an act of intimacy with geology. In the Canyon, a walk from rim to river is also intimacy with the immensity of Earth's time. Cross sections of rock, rising from the oldest layers to the most recent, offer insights into an Earth being built. Hiking here becomes the equivalent of time travel. Stand next to rock 1.7 billion years old in the Inner Gorge, and you and that ancient layer of rock share a single moment in time. (Time travel on the walk back up is especially nice, because when you reach the top of the trail, you are much younger.) "The rock tells the story," Billingsley says. “The more you get into it, the more you get lost in time.” He has mapped 18,000 square miles of the Canyon and its surroundings; these rocks are his familiars. Billingsley and Huntoon were part of the initial geological mapping of the Canyon. In 1969, as students working in the Canyon, they came in from the field to attend an annual geology symposium organized by the Museum of Northern Arizona. Although it no longer happens, the symposium was a major event in the world of geology.

At that time, recent publication of a parkwide topographical map made the idea of a parkwide geological map feasible. “Topos” provide a base on which to build the structure of the Earth. Most hikers use topo maps. Informing us exactly where we are physically, they allow us to identify peaks and streams, find our routes. But following contours, as if a walk into the Canyon were some ordinary hike, misses the point. No hike to the river and beyond, or to the river and back, is ordinary. The contours cannot tell us the rocks' story. Not reading a topo correctly may get us lost in the Canyon, but not in time.

Enter the “Blue Dragon,” the name given to the project to map the park's geology. Or, rather, the name that evolved out of the map itself. It can only be a dragon, the magnificent blue beast winding across the geological map of the Grand Canyon. Obviously a benevolent dragon, as Asian dragons are, it seems like a water deity carrying the lifeblood of the land across the plateau it carved and chiseled into a living map of time.

Work on the Blue Dragon began in 1970. Eight geologists, Billingsley and Huntoon among them, went to work on variously assigned sections of the Grand Canyon. Six years later, the first geological map of the Canyon was published. This did not mean that every geological facet of the Canyon had been mapped - although, for a nongeologist, it is hard to imagine that when working with rocks in place for millions of years, anything would be hidden.

Obviously, the Surprise Canyon Formation was. Until its discovery, geologists traditionally included the rock of the Surprise Canyon Formation as part of the ubiquitous Redwall Limestone beneath it or the Watahomigi Formation (part of the Supai Group) above it.

USGS Bulletin 1605-A, titled Stratigraphic Notes, 1984, calls the Surprise Canyon Formation “a new name applied in this report to rocks previously considered to be part of the Redwall Limestone and the Watahomigi Formation.” While the Surprise Canyon Formation isn't something that just happened recently, it does allow us to see easily how something existing in plain sight might also be something to be discovered. I thought geology provided us a sense of order, of everything being in place. Instead, geology is fluid, the Earth as dynamic as the human mind.

As for the Blue Dragon, it remained a living thing as corrections and updates were made to each subsequent map. But at that June 2019 NAU lecture, Huntoon, acknowledging the inevitability of change, said, “Our map is slowly becoming obsolete. New things are coming along in the Grand Canyon every year. Everything in science is transient.” Billingsley offered his own view of transience, showing us photographs of Navajo Falls in 1968 and again in 1980, and of Supai Falls in 1970 and again in 2015. We saw that each waterfall has visibly migrated. “I never thought I'd live long enough to see it visually changing,” Billingsley said.

When even a geologist is surprised by the rapidity of change, it might seem the rest of us can be forgiven for looking at rock as more permanent than, for instance, watercourses or glaciers. Although we know that earthquakes and volcanic eruptions make change an immediate event, most of us still think, as Billingsley voiced, that geological change isn't something we're apt to see in one lifetime. I even remember - a long time ago when I thought geology was a prehistoric event, all over by the time I was born. I thought all mountains were already built, all canyons long since carved. Geology was not something alive, like a rose. Then, one day, I watched an enormous rockslide down a mountain slope. When the dust cloud finally lifted, the mountain was changed, the trail beneath it obliterated, the top of the meadow where I sat an altered landscape.

On another occasion, an alpine guide I knew took a client to an area where a giant boulder had rested at the bottom of a mountain for what the locals considered thousands of years. It was a tourist attraction because of its interesting balance on a relatively small base, and people wanted to be photographed beneath it. As my friend's client did. In the moment of that photograph, the boulder dislodged and the client was crushed.

My friend gave up guiding after that. Geology happens. AH

PUTTING THE CANYON ON THE MAP

Before there was the “Blue Dragon,” which is mentioned in the accompanying story, there were U.S. Geological Survey topographical maps of the Grand Canyon. The first of these maps was published in 1903; the Bright Angel section of the 1906 version is shown here. USGS geologist François Matthes led the initial mapping expeditions in 1902 and 1903. “We found ourselves face to face with a barrier more formidable than the Rocky Mountains – an abyss 280 miles long, containing an unbridged, unfordable, dangerous river,” Matthes recalled in a 1928 Arizona Highways story.

But trailblazing topography wasn’t the Matthes expedition’s only contribution to the Canyon. At the time, there was no convenient route from the North Rim to the Colorado River, and Matthes recalled that the group had been told Bright Angel Canyon, the most obvious place for such a trail, “afforded no practical route for pack animals, and might be impassable even to the foot of man.” Undaunted, the group pioneered a path down the side canyon, crossing Bright Angel Creek more than 90 times along the way. “Of accidents there were more than can here be chronicled,” Matthes wrote, “but none of them, fortunately, was of a serious nature.” These early maps are notable not only for their detailed topography but also for their man-made features – or lack thereof. This map shows no road to the North Rim and only sparse development at the South Rim, and the Bright Angel Trail – which today is the Canyon’s most popular trail – is labeled here as the Cameron Trail (see He Took a Toll, page 18). Several old Grand Canyon topographical maps are available via the Library of Congress, and backcountry hikers sometimes use them to find remnants of trails that are no longer in use. – Noah Austin