By Christian Wright
Guide at Holiday River Expeditions
Most people driving across the Green River Desert on Interstate 70 make few stops along the way. On an average summer’s day, looking out from a car’s air conditioned windows it seems the whole universe has turned to a burnt, waterless desert. The monotone yellow of the Mancos Shale formation, the remnants of a Cretaceous sea that makes up the ground in all directions including the first several hundred feet of the continuous cliffs to the North, appears bleached out in the mid day sun. Taking off one’s sun glasses and stepping out of the car it’s difficult to focus on anything, the surroundings are so bright. Evidence of human civilization is slim. Evidence of water even slimmer. Many, finding themselves in a trek across this wasteland, are so awed by the inhospitability of the landscape that they happily top off their tanks for $4.25 a gallon of regular unleaded in Crescent Junction.
And like most travelers, they suffer for their haste. The real last stop for Westbound traffic isn’t for another 20 miles. There, at Green River, the gas stations in and outside of town are the real last stop. The next 107 miles until Salina is the longest distance without services of any kind along the entire US interstate system.
Another consequence of the same haste is that the fascinating geology, ecology, and numerous historical sites of the Mancos Badlands / Cisco Desert / Book Cliff complex gets overlooked and forgotten, as one rushes to redder, magicaller rocks to the South!
As for being a “wasteland”, the landscape may be forgiven, for it certainly looks the part. For over a hundred miles it appears almost completely devoid of vegetation of any kind. In fact, except for a scattered and untrustworthy few green specks along the higher slopes, the only green a traveler sees at all before reaching the irrigated fields of Green River are occasional stands of greasewood following a desert wash, or perhaps few distant Pinons and Junipers along the slopes of the Salt Valley Anticline.
But despite appearances and names, it really does rain here. In fact, it can rain quite terribly, in apocalyptic torrents of hyper-localized downpours. Deep gullies carving slopes of Mancos Shale and the alluvial trenches that characterize most normally dry washes in this area are evidence of the erosive power of such storms. The Cisco Desert (or as it is called farther West, the Green River Desert) is a desert by all appearances. But here, a lack of precipitation is not the primary reason for the scarcity of vegetation.
The Mancos shale, a crumbling mudstone that instantly turns to an expanding, tire-sucking glue at the slightest precipitation, swells and contracts with the addition or removal of moisture, causing trouble for most plants’ root systems. Furthermore it is also rich in selenium salts, which makes growth for anything but the hardiest species quite difficult.
Recall the verdant greasewood, which you may have seen before, perhaps along the Salt Flats of I-80 where its tolerance for alkaline soils makes it, again, the only green plant you will see not on a mountain anywhere between Salt Lake and Wendover. Here on a side road, such as the poorly maintained “Danish Flat” (formerly East Cisco) exit, the plant sprouts up on either side of the narrow pavement, thirstily drinking up the runoff that collects on either side of the pavement.
Still too low to the ground (and too prickly!) the greasewood would provide shade only to the most desperate wanderer willing to crawl inside of one. A better bet for a tired driver on a summers’ day would be to pull over along one of the Cisco road’s many bridges over normally dry washes. In the Cisco vicinity, these provide the only shade there is between the Book Cliffs and Dewey Bridge. And should you become a hitcher, your best bet is to stay put! Try and get dropped off near a shady bridge, or even a roadside sign!
Animal life as well, despite appearances, is not as absent on the badlands as one may expect. Turning off onto one of the dirt roads off any I-70 exit, and heading either North or South along the wide, flat expanses of rolling badlands, one is fairly likely to encounter herds of Pronghorn, particularly at early morning on in the evening. It’s ideal habitat for the creature, whose primary defense from predators lies in early detection via keen eye sight and wide country, as well as speed to elude them. Cottontail Rabbits are abundant as well, often burrowing into the sides of washes, and living off grass and greasewood leaves, too salty for livestock but palatable to the cottontail. Rabbits in turn, along with smaller rodents, sustain a population of coyotes, who prefer to hunt at night, where they are far more often heard than seen. Glamorous and apex predators come in the form of Mountain Lions, highly secretive and almost never seen, and a variety of Golden and Bald Eagles and Red Tailed Hawks. Often, one or the other of these birds of prey can be seen upon some roadside hill, surveying its territory and watching for any sign of smaller, rodential movement.
A great place to casually study the difference soil type can make in ecology is towards the end of one’s drive to the put in at Westwater Ranger Station, the start of a popular, class III-IV, 17 mile river trip. Westwater Canyon has been cut through the farthest Northwestern slopes of the 10,000 foot Uncompahgre Plateau. Like most regional uplifts in the four corners’ area, the uplifting of the Uncompahgre brought much older, and elsewhere buried, formations of sedimentary rock to the surface.
Shortly after leaving the interstate the drive to Westwater is through a small drainage, with hills about a hundred feet higher than the road on either side of it. But look closely, do you notice a difference? On the right, as you head towards the river, is yet another slope of Mancos Shale. Entirely devoid of any green plants. But to the left, and not at a higher elevation than the slope on the right, is a slope containing many healthy juniper trees. And the “ground”, cropping out often from beneath a thin layer of topsoil, is the older Dakota formation, a cliffy, white, stream mouth / beach deposit. Relatively selenium free, and without the cycles of expansion and contraction that characterize the Mancos Shale, the Dakota is a welcome host for desert plants, and these in turn sustain a more diverse population of herbivores, such as the mule deer, rarely seen in the day but at night a hazard to hasty drivers.
On an earlier drive, perhaps from Crescent Junction to Moab, you may have gazed into the gaping heart of the collapsed Salt Valley Anticline, noticing as you did that the rocks inside it, and on the slopes of it, were very different from from the flat yellow you were driving on. Again, it was the Dakota that formed the next oldest layer after the Mancos, and whose horizontal bedding has been turned up on either side of the anticline, allowing, again, those Junipers we spoke of earlier to grow, and which are visible as a prominent long, high, green ridge from Crescent Junction to Yellow Cat Flat.
Once the retreating shore of an advancing sea, the Dakota was eventually buried by the muds of a seaway that around 90-80 million years ago connected the Arctic Ocean to the Gulf of Mexico. In geologic terms the Mancos Shale is said to rest “comfortably” on top of the Dakota, meaning the change in one deposit to the other was part of a continuous transition. There was no pause in the depositional process as environments changed, nor any missing layers that had been eroded in some intervening period of time. For several million years, as the beach / Dakota was spreading ever further East and West while the seaway expanded. Once overcome by the waves the Dakota soon became buried beneath thick, fine grained muds that slowly accumulated on the bottom on the sea. Highly fossiliferous, the Mancos has preserved numerous examples of marine life, from humble bivalves an inch across to Plesiosaur, the “Loch Ness Monster” looking long necked sea monster with four powerful flippers, each up to five feet long!
In the vicinity of I-70, the layers of Sedimentary strata from the top of the distant Book Cliffs to the lower, buried layers, have been tilted upwards to the south. This gives a very deep formation a much shallower appearance. Imagine, the height of a neatly stacked deck of cards being held at the edge of a table. Now, while holding the deck, tilt it down off the table so what was once a vertical edge of the deck is now tilting upwards, diagonally where it was once vertical, witch a majority of the whole deck (deposit) now unseen beneath the table’s top. Such is a common analogy used to describe the tilted Mancos, which in places has been measured as a deposit to a height of 4,000 feet!
What could have been responsible for such tilting? One one two things. Either the Southern boundary of the formation was lifted, or the Northern boundary of the formation was “sunk”, pulled down by continental subsidence. In different degrees and at different times, both processes have here effected the entire stratigraphy of the book cliffs, from the higher formations above the Mancos to the buried Mesozoic and Paleozoic deposits underneath it.
The large plateau above the Book Cliffs is known as the Tavaputs. The remote Sand Wash “airport”, a high point on the plateau’s Northern, rising flanks, presents a view where this tilting upwards to the South is quite visible, as well as beautiful!
Younger sedimentary rocks, mostly Green River Shale, are here exposed, high above the buried Mancos.
In certain areas, large isolated profiles of the Mancos Shale have been revealed, less obscured by overlying sediment. For example, here’s one of the highly photogenic buttes of Cathedral Valley, just east of Capital Reef National Park.
The entire complex is Mancos shale. Including the top, cliffy layer. Sort of. You see, different types of sedimentary rocks are deposited by different environments. In this case, a cliff forming sandstone makes up the butte’s caprock, while a crumbly hill of marine shale makes up its base. As one depositional environment changes to another, a different sort of rock can of course deposited above the old one. But environments do not always directly change one to the other. Sometimes long periods of interfiguring occur, as, say, glaciers at the poles advance and retreat in cycles over several million years, raising and lowering the sea level, and subsequently allowing stream deltas and sea floors to alternately deposit their sediment atop one another.
Such is the case with the Mancos Shale, and its overlying deposit, the Mesa Verde Sandstone. Turning once again to face the book cliffs, one notices the slopy grays and yellow (Mancos changes from dark shale rock to light yellow mud the longer it is exposed to sunlight and weathering) of the lower book cliffs gradually give way to a yellow cliff face without any sloping grays. The higher, yellow / white / occasionally reddish cliff face, is the Mesa Verde sandstone. Here’s a nice profile of the height of the Mesa Verde as it towers above the former coal camp of Standardville, in Spring Canyon West of Helper. The ground level is around 6,500 feet. The top of the mountain in the distance is above 8,500 feet.
Here in coal country, much of this deposits’ fossiliferous evidence has been unearthed for our appreciation by the hard work of miners. Dinosaur footprints found in coal beds are on display at the Western Mining and Railroad Museum in Helper as well as other museums across the Colorado Plateau. Petrified wood was often thrown out of coal cars as a waste rock, where it can be found today in slag heaps. And numerous features in the sandstone itself, such as stream bed “lenses” and ripple marks, can be found much more abundantly, providing evidence to the conditions that first created the deposit.
Now you may ask, “Isn’t Mesa Verde a National Park in Colorado?” Well, yes it is, and it is the “type area” for this sandstone, the area from whence the name derives. It, like the Mancos, is a very large deposit. The seaway, later replaced by a stream and swamp environment where the harder Mesa Verde formed, covered a broad area. Many Western Colorado and Eastern Utah towns- Vernal, Green River, Price, Grand Junction, Mancos, Cortez, and Durango, are located on one or the other formations.
But the Mancos- Mesa Verde contact is not so simple as simple stratigraphic superposition. “Interfingering” was mentioned earlier. This you noticed outside the Holiday operation in Green River, or perhaps along Highway 191 between Green River and Price, where the slopey Mancos on the lower cliffs was interrupted by a nearly continuous horizontal band of cliff forming sandstone- an insurmountable barrier to any climber- and only afterwords was replaced by yet another band of slopey shale. Further to the North, at Helper, Utah, the Book Cliffs and the Wasatch Plateau come together at the upper end of the Mancos- Mesa Verde contact, where the bands of shale finally give way to thick sandstone for good.
Within the slopey Mancos shale, different depositional environments have deposited different sandstone “cliffy” layers of sandstone. The lowest layers represented offshore sandbars and marine beaches. Successive sandstone layers, deposited after many years and many thousand feet of shale had already accumulated, represent a transition to a stream deposited continental environment. Midway up the difficult to divide transition between sandstone beach layers within the Mancos and sandstone stream layers of the Mesa Verde are several thick seams of coal. These represented thick, slow gradient, freshwater or brackish swamps. The highest sandstones represent freshwater streams. Eventually, beds of slope forming sea floor get thinner and thinner until they disappear completely. This marks the final retreat of the sea from the Colorado Plateau, which occurred as the Laramide Orogeny (mountain building event) began, which built today’s Rocky Mountains and raised the average land elevation far above the reach of the sea.
The interfingering here between shale and sandstones is largely the result of climate changes. There is, for some reason incomprehensible to myself, currently a debate among some humans in this country about whether or not climate change happens, happens as a result of man made activity, or even ought to be a concern at all! It is easy, I suppose, to have interminable “debates” on the basis of personally formed opinions when that is one’s starting and ending point. However, when scientific evidence is taken into account, and conclusions are first proceeded by research and careful study, there is an overwhelming consensus among over 95% of scientists on the planet that human activities, namely the burning of fossil fuels, are resulting in a warming of earth’s average temperatures.
But certainly, burning fossil fuels was not responsible for the rises and falls in sea level in cretaceous time! Gradual advances and retreats of sea levels of hundreds of thousands, or even millions of years, were largely the result of glacial advances and retreats in the polar regions. An advance of polar snowpack lowers sea level. The melting of polar ice caps raises it. Thus we can locate today saltwater clam fossils and ancient shark teeth in the Mancos Shale, high above a lower Mesa Verde coal seam, itself an organic “fossil” of verdant freshwater to brackish lagoonal plant life, abundantly containing petrified wood and even land animal tracks. Of course, in some ways, the dinosaurs of the Cretaceous had an easier time dealing with sea level rises and falls. Sea levels rose and fell gradually, giving Iguanadon generations to causally migrate East or West along his preferred coastal hunting grounds, which is more time than my geologists tell me we may have before the ice caps melt. Iguanadon was also spared the liability of having invested billions of dollars in coastal cities, sea ports, housing, and infrastructure. There were also many fewer Iguandons then there are today humans, and Iguanadon was less concerned with passports, fences, and national boundaries when climate changes pressured him to migrate than we currently seem to be obsessed with.
I am sure, however, there were dramatic instances of conflict among various Iguanadons, trapped on smaller coastal peninsulas, where the number of crowded animals began to exceed the amount of food available to them. And the lowly clam, whose mobility has never been a distinctive evolutionary advantage, was certainly left high and dry when the sea level dropped. I am told today by certain authorities that our discoveries of airplanes, automobiles, buses and interstate highway systems allow us a deal of greater mobility. But events as recent as 2005 in a certain coastal lowland dear to me have demonstrated how incapable we often are of efficiently utilizing these systems, even when rising waters are imminently obvious to everyone!
Like the Mississippi River, which on its own terms wanders periodically as it changes course to deposit itself over various areas of the Gulf Coast, the rivers that drained the ancient and now completely eroded Sevier Mountains in West- Central Utah in Cretaceous time meandered and wandered, replaced and retraced their former flows so that the banding layers of sandstone we see today where once they flowed came to cover a massive area. And the assertion I have just made regarding direction of river flow is not mere conjecture! One of the best ways to understand direction of flow in ancient sandstones is to look at grain sizes of the same stream deposit from one area to another. The farther West we go, towards the Wasatch Plateau, the larger, on average, the sand grains of the Mesa Verde tend to be. The further East, the smaller they get. This same process of sediment sorting is characteristic of all rivers. The bed of a high energy, low volume Rocky Mountain trout stream is composed of larger rocks and cobbles, than say, the tiny sand and silt sediments the Colorado River is depositing in large quantities at the head of Lake Powell.
The deposition of extensive coal beds has been the most significant economic legacy of the Cretaceous period in Utah, particularly in Carbon and Emery Counties, where by the 1890s an industrialized island of coal camps, coke ovens, and railroad yards largely staffed by Southern and Eastern European immigrants (as well as Japanese, Finnish, Black, Mormon, and a few protestant “Anglo” workers) contrasted greatly with the dominant ethnic, religious, and economic makeup of the rest of the state.
At the Eastern end of this activity, the largest coal mining camp in Utah’s Grand County is today the lonely ghost town of Sego. Once home to over 300 workers, today Sego contains numerous fascinating and photogenic ruins just up the right fork of the canyon above the popular rock art site 3 miles North of Thompson Springs. Coal was mined at Sego from the early 1900s until the railroad replaced steam engines with diesels in the 1950s and coal stoves were replaced by other fuels for cooking and heating. Here the seam is several feet thick, and large quantities of the mineral still lay about in heaps at the face of the mine.
A detailed Geologic cross section of the numerous interfingerings of shale and sandstone can be a rather complex and confusing diagram to look at. Several “groups” of sandstone – shale sequences are named, but not all occur at the specific area you may be looking at. Some were never deposited there, and others have long since been eroded away. The Blackhawk Group, for example, is an economically important grouping of several sandstone layers that contains much of the coal that has been mined in the Book Cliffs / Wasatch Coal Field. The Star Point Sandstone is another, and an actual visit to Star Point on the Eastern boundary of the Wasatch near Wattis exposes its fabulously tall, steep sandstone face. The Ferron Sandstone is one of the lowest and oldest sandstone seams, widely considered to be a marine sandstone and a part of the Mancos Formation. This layer is visible in great thickness and detail as you drive through the Ferron Anticline, where the formation is well exposed on either side of Highway 6/191 just south of Wellington.
The town of Cisco itself might be a good enough place for us to conclude our discussion. Originally a railroad station where steam engines took on water pumped up from the nearby Colorado River, and ranchers loaded cattle that had fattened upon the slopes of the La Sal Mountains, Cisco grew in the early 20th century through an expansion of sheep herding and an oil boom. Decades later filmmakers discovered it, and if you have been there, you will probably recognize some of the older buildings, the town Post Office, or the Book Cliff profile from such films as Thelma and Louise, Vanishing Point, or Don’t Come Knocking. While audiences enjoyed the scenery, the town itself profited very little from these endeavors. The remote location was always a liability, and winters were cold and harsh- the effects of climate being compounded by inversion, as Cisco has been built in a hole, the land all around it higher than the town itself.
The final death blow came with the construction of Interstate 70 through Eastern Utah in 1972. One of the last sections of Interstate to ever be built (though the Glenwood Canyon section in Colorado was not completed until 1992!), I-70 at times followed exactly the older route of Highway 6, and at others it diverged. Here, it passed to the North of Cisco by little over a mile, but no convenient exit was built to the town. Instead, two exists were built, one several mines to the East, and the other several miles to the West. Neither was close or convenient enough to justify the time it took busy travelers to drive along the old Highway 6 grade to find a bite to eat or fill up on gas. By the 1990s, the gas station and store had closed, and the last restaurant (Ethyl’s, the last building on the left as you drive Westbound through town) and followed suit. A year ago the Cisco store had an occupant and even a horse, but since then the premises have been quiet. Along with their chickens, goats, and several native White Tailed Prairie Dogs, two hermits at the South and East end of town make up Cisco’s only residents, and the post office has long since been abandoned in favor of a small, outdoor PO Box stand. A graveyard of abandoned cars and campers winds throughout the town, some of the vehicles providing parts for a mechanic, others apparently left to their own devices. Today, Cisco is perhaps Eastern Utah’s most ubiquitous and accessible ghost town. An eccentric and mysterious relic that continues to set the tone for many thousands of visitors to the Moab area each year.
Yes, there is far more on offer here, for the interested traveler, than a last place to fill up on water or a better deal on Gasoline. The southern slopes of the Book Cliffs, exposed to the interstate along a 250 mile continuous escarpment from Palisade, Colorado to Helper, Utah, are a land of many secrets. To many from other states, or other parts of the state, a vacant wasteland is all this represents. In the 1960s, the vast, uninhabited land prompted the federal government to choose Green River as the site of a Missile Launch Complex, where Athena Intercontinental Ballistic Missiles were tested through the 1970s. Here they were launched towards the White Sands Missile Range in New Mexico, over the heads of vacationers in Canyonlands National Park, who would occasionally joke about the odds of a booster stage falling to earth upon them.
The few hundred members of the military and civilian employees who came here for the jobs this facility provided were following in the 70 year old footsteps of agriculturalists who saw in the Green River valley what they couldn’t find in the high land prices of Fruita and Palisade. Today the same qualities of open space, along with distance from the Colorado River and the impermeability of the Mancos Shale, is behind the decision to relocate several million tons of Uranium mill tailings now sitting on a floodplain north of Moab here at the base of the cliffs by Crescent Junction. A nuclear powerplant, projected to be built at the town of Green River itself, would along with the tailings pile amount to much controversy and worry for may local residents, and significantly change the character of the sleepy town of 850 melon farmers, hotel workers, and river outfitters.
Like most extractive energies, the decision of whether to build this plant, along with the controversial wisdom of the continued burning of job providing yet polluting coal, poses great questions and challenges a state that gets 98% of its electricity from coal and natural gas. Generations of intensive grazing, oil and gas development, uranium and coal mining have quantified the value of the Cisco Desert and Book Cliff areas in little more than crude economic terms. Today a multi million dollar tourism industry benefits from a different, intrinsic value of open and “unspoiled” places. How these areas, such as the Book Cliffs Wilderness Study Area, the water and land potential of Green River, or the Mancos Badlands along I-70 get used is an ongoing debate.
But whatever your background or priorities you are likely to benefit from a little more time spent along the exits in this “land of many uses”, that so many drive past without giving a second thought to. While this article has touched on a few topics, there is so much more to be discovered, and appreciated. Yellow Cat Flat, the Morrison Formation, Arches National Park, Desolation and Labyrinth Canyons, the San Rafael Swell, all are highly interesting destinations more popularly attended to than the land I have just described. It’s a place one could easily spend a lifetime, getting to know the deserts’ little ways…Blog Home