Along the Greenbelt and Among the Grasses

①Faulting uplifts bedrock to form the mountain mass.

②Streams erode the mountains and begin to deposit sediments in the valley.

③Streams continue depositing valley sediments eroded from the mountain mass.

④Streams have now cut clear through the sharply eroded mountains and formed steep-walled canyons.

⑤All but isolated mesa remnants of the mountains have eroded and weathered away. The riverbed rests in the deep layer of sediments.

⑥In a future stage the bedrock mountain uplift might be entirely eroded away to become a deep layer of sediments.

When you think that the Earth is perhaps 4.5 billion years old, that complex organisms have existed for no more than about 700 million years, that the oldest rocks exposed in the park are 300 million years old, and that fossils of backboned animals in the park cover a time span of 70 million years, you can realize how fragmentary the fossil record really is. You get few glimpses of the relatively recent past, but these are astonishing.

For example, geologists know that back in the dim dark distances of Earth time, Big Bend lay repeatedly at the bottom of the sea. Convulsions within the Earth repeatedly raised these sea floors to the tops of mountains, and time after time these mountains wore away. One of the ancient ocean beds can be seen at Persimmon Gap where, in remnants of the park’s oldest mountains, fossil sponges, brachiopods, and other simple marine organisms lie exposed. For hundreds of millions of years the three-lobed trilobite was among the most prolific animals in the world, but it had long been extinct when the last great ocean, the so-called Cretaceous sea, washed across Big Bend. Most of Mexico lay submerged and a sort of mid-continent seaway cut North America in two about on the line of the Rocky Mountains. In its early stages this sea harbored ancestral clams, oysters, snails, corals, and a coiled shellfish called an ammonite. You can see these animals preserved in the limestone walls of Santa Elena Canyon. Giant clam shells a meter (3 feet) across and fossil fishes preserved in the round between Boquillas and Mariscal Mountain tell us what lived in later seas. Sea turtles, sharks, and a 9-meter (30-foot) marine lizard that swam in the open ocean have left their remains in the yellowish badlands near the park’s western entrance.

Late in this oceanic period the Rocky Mountains began to rise to the north of Big Bend, the Sierra Madre to the south. The park’s own Santiago, del Carmen, and Mariscal ranges, and the first upward thrust of the Chisos also occurred at this time. As the mountains rose and started to wear away, delta deposits began to build out farther and farther into the seaway, forming barrier bars and tidal shelves where turtles, snails, oysters, and sharks lived and died. Gradually the near-shore, subtidal environment changed to a tidal flat. This in turn changed to marsh, to beach, to brackish and freshwater lagoons,and finally to an estuary and river floodplain environment. Such was the Big Bend world to which the dinosaurs came. They had been ruling the Earth for eons, but they did not reach the park until the Cretaceous sea withdrew.

Ammonite impressions (top) and fossil clams reveal the era in which the Big Bend area repeatedly lay beneath a shallow sea. Fossil finds show that today’s mountaintops were once sea bottoms.

Fossil clams.

Sloshing about in the freshwater were amphibious and semi-aquatic species. Probably commonest was the duckbill dinosaur, an enormous reptile that walked on huge hind legs. It had as many as 2,000 teeth. Specially adapted for grubbing up and munching freshwater plants, these flat grinders occurred in batteries in the duckbill’s jaw. As a tooth wore out, another popped into place.

Tramping about on all fours and peaceably cropping land plants were bizarre looking horned dinosaurs with turtle-like beaks. For their weight they must have had the most powerful jaws of any backboned animal that ever lived. Armored species included one that looked like a horned toad the size of a dump truck. Another sported a huge lump of bone on the end of its tail, still another a thick lump of bone above a brain no bigger than the end of your little finger. The world’s largest crocodile, a 15-meter (50-foot) creature with 15-centimeter (6-inch) teeth, turned up in the park, but remarkably few bones of meat-eating dinosaurs have ever been found. One of the Earth’s great mysteries is why, at the top of their terrific form, the dominant dinosaurs died out? This happened in a geologically short time all around the globe. Perhaps it was because the highly specialized reptiles couldn’t cope with changes in their environment as the world climate grew cooler and more continental. No one really knows.

When the Age of Mammals began some 64 million years ago, Big Bend lay on an alluvial floodplain where summers were moist and winters were mild. Shallow rivers meandered between natural levees wooded with flowering plants, sycamore, stinking cedar, and tree ferns. Garfish swam in rivers and isolated ponds, while small lakes and swamps lingered on in meander cutoffs and abandoned river channels. It was a land where seasonal floods alternated with dry periods and where, during protracted dry spells, treeless areas invaded the forest.

Garfish and turtles in the Rio Grande give us a hint about life here 50 million years ago. Then they swam in waters haunted by crocodiles and visited by the modern horse’s earliest ancestor, Hyracotherium; the hippo-like Coryhodon; and Phenacodus, an early species of ungulate related to both hoofed and clawed mammals.Fossils of these and other animals belie dry and barren Tornillo Flat’s earlier Eocene life as a lushly vegetated landscape, as depicted in this reconstruction.At the time of this scene the dinosaurs (“terrible lizards”) had been extinct for 15 million years. Their fossils occur here too. Remains of the giant Pterosaur have been found. These “winged lizards” were flying reptiles whose 11-meter (36-foot) wingspan exceeded that of small jet fighters. The wing was a featherless membrane stretched out from the reptile’s body to the tip of its greatly enlarged fourth digit. Fossil remains of Brontosaurus, Allosaurus, Icthyosaur, and others have been found. Fossil Ammonites (seepage 67), related to today’s sea-dwelling chambered nautilus, represent the even earlier period when today’s Big Bend was covered by a shallow inland sea. Sample fossils are displayed in a shelter off the Marathon entrance road near Tornillo Creek bridge.

Fossils of these and other animals belie dry and barren Tornillo Flat’s earlier Eocene life as a lushly vegetated landscape, as depicted in this reconstruction.

At the time of this scene the dinosaurs (“terrible lizards”) had been extinct for 15 million years. Their fossils occur here too. Remains of the giant Pterosaur have been found. These “winged lizards” were flying reptiles whose 11-meter (36-foot) wingspan exceeded that of small jet fighters. The wing was a featherless membrane stretched out from the reptile’s body to the tip of its greatly enlarged fourth digit. Fossil remains of Brontosaurus, Allosaurus, Icthyosaur, and others have been found. Fossil Ammonites (seepage 67), related to today’s sea-dwelling chambered nautilus, represent the even earlier period when today’s Big Bend was covered by a shallow inland sea. Sample fossils are displayed in a shelter off the Marathon entrance road near Tornillo Creek bridge.

Pterosaur

Extinct mammals.

With such a wealth of habitats a whole new host of animals took over Big Bend. Crocodiles and turtles hung on from the Age of Reptiles, but nature’s evolutionary torch passed to the warm-blooded mammals who increased rapidly in numbers, size, and diversity. Remains of 29 species of early, extinct forest-dwelling mammals have been discovered near the Fossil Bone Exhibit site on Tornillo Flat. This same floodplain later accommodated a hippo-like plant-eater, a browsing collie-sized mammal, a panther-like cat, and the little ancestral horse, Eohippus. No bigger than a fox terrier, Eohippus had not yet developed the typical horse hoof and still had four toes on his front feet and three on his hind. He browsed among low forest plants, because nature hadn’t yet invented grass.

Some 20 million years ago, when we get our next glimpse of the Big Bend, grasses were well established and the Earth began to witness the rapid rise of grazing animals. In the park, Castolon had a savanna-type environment, with a sub-humid to semi-arid climate. Rabbits and camel- and sheep-like mammals flourished. Plant eaters ranged in size from a tiny mouse to an enormous rhinoceros. This giant was about 3 meters (10 feet) long, stood 2 meters (7 feet) high at the shoulder, and had massive, bony horns on its head. There were also carnivores to fatten on the herbivores.

In the middle of the Age of Mammals, Big Bend country became the seat of widespread and repeated volcanic disturbances, with lava flows, ash falls, and mountains bulging up like blisters as they filled with molten rock. Here, most of these events centered on the Chisos, where the signs can be seen in mountain peaks to this day. Much of what happened since has not even left a shadow; the record and the rocks have both been erased by millions of years of weathering and erosion. But you can see “living fossils” in the high Chisos canyons. These are the ponderosa pines, Arizona cypress, and Douglas-fir trees descended from the moist woodland species that populated this region during the last Ice Age. Occasional remains of the great Ice Age mammoths have also come from gravels in deeply eroded ravines. And you can see all around you the evidence of two latecomers who seem to have reached Big Bend around the same time: Man and the Desert. But here, deep in the river’s canyon, both are apparently as remote from you as your own daily world.

University of Texas paleontologist Wann Langston excavates the sacrum of an extinct sauropod dinosaur. These bones were excavated near Tornillo Creek.

This huge cottonwood tree casts its shade along Terlingua Creek. Early settlers of Big Bend greenbelts used the cottonwood for roofbeams. Later, the trunks shored up mine shafts.

Even in the dead of night it smells green beside the silt pond at Rio Grande Village. Well,dustygreen perhaps, but redolent with reeds and shrubs, trees and grass, with the very jungle breath of the floodplain. On the other side of the river a lone cock crows and close at hand there’s a rustling of leaves, a crackling of reeds, the lap-lap of some animal drinking. Leopard frogs croak on in unconcerned bass and baritone burps, sounding like someone’s stomach talking. But all at once something has a frog for dinner and the unwilling meal keeps pumping out shrieks, faster and faster and louder and shriller, to the last breath. Then silence. The frog chorus grumbles on.

In the morning you find the flat-footed tracks, long-fingered as a human hand, of that nocturnal hunter. The raccoon is an omnivore, an opportunist with a taste for whatever it can find: amphibians, shellfish, mesquite beans, acorns, cactus fruits, rodents, garbage. The little masked bandit can in fact make himself a campground pest. His dependence on water keeps him a prisoner of the floodplain, but the river, the springs, the sloughs, and the ponds provide abundance in a narrow green world unrolled like a ribbon across the desert. Sometimes this greenbelt, as it is called, is no wider than a bush; in places it may measure three-quarters of a kilometer (half a mile). And it keeps changing, widening with floods, narrowing in droughts, altering course with the river itself.

Just such a change of channels apparently created the bench of bottomland where Rio Grande Village lies today. People have been camping here for thousands of years, as shown by the many deep mortar holes where meal was ground in the limestone ledges near the pumping station. Certainly the place had much to recommend it: wood and water, abundant game, rich soils, an agreeable winter climate, and beautiful views of river and mountains.After the white man came to stay in the early 1900s most of the native flora changed. Farmers cleared the bottomland to plant cotton and grains, cut down the lanceleaf cottonwoods for roofbeams, dredged ponds and ditches, and enclosed springs. Nowadays, the plants you see are often exotics brought in from outside to create shade and lawns.

Such are the eastern cottonwoods with their heart-shaped leaves, the evergreen live oaks and smooth sycamores, the sweet-smelling honey locust and eucalyptus trees, and that fine green carpet of Bermuda grass. Like the farmers’ field crops, these interlopers cannot flourish without irrigation and sometimes even that is not enough. Dozens of eastern cottonwoods have died in recent years.

A good place to see native plants and animals is along the Rio Grande Village Nature Trail, which starts at the campground and leads to a hill above the river. A walk along this trail is doubly interesting because it shows greenbelt and shrub desert side by side, the two habitats often separated by less than a vertical or horizontal meter. The jungle starts at the edge of the clearing and almost at once you come upon a warm spring run. This may be where the rare little Big Bend mosquitofish,Gambusia gaigei, originated, but all you see today is a larger relative,Gambusia affinis. These five-centimeter (two-inch) predators, little as they are, soon take over. They apparently are invaders from the Rio Grande.

In wet weather this whole spring area becomes a swamp and even in dry times moisture-loving plants crowd the trail. You pick your way beneath black willow trees and grapevines festooned with wild grapes, stop to admire the yellow tube-flowers on the tree tobacco, stoop to avoid a spear slanting from the solid wall of common and giant cane. These two tall woody grasses stand 4.5 meters (15 feet) high and put out great, plume-like flowering heads that shine silver in the sun. Indians used the stems for arrow shafts and ate the roots raw, roasted, or boiled. Many an early settler roofed and even walled his house with cane. Today the reeds supply deer and cattle with attractive browse, and the thickets serve both as home and hunting ground for birds, small mammals, and reptiles.

Here is the cleverly constructed nest of a gray wood rat. And there, crouched beneath a bush likesome storybook monster is an enormous spiny lizard. Rosy and gray, he peers back unblinking, still as a stone, then melts away so quickly he is gone before you see him move.

A little further on the trail climbs a short rise, topping out on Chihuahuan Desert complete with creosotebush, dog cholla, ocotillo, and the standard collection of cactuses. If you take the trail in spring or summer, the mound-building strawberry cactus will be covered with hot pink blossoms and delicious fruit. By fall the fiercely barbed blades of the false-agave, or hechtia, will have taken on a reddish tinge. In wintertime the tasajillo cactus will be dressed like a tiny Christmas tree in long green spines and bright red fruits. But at any season this water-starved scene stands in sharp contrast to the marsh, rank with reeds and bulrushes, that lies just below.

Unlikely as it may seem you are looking at a beaver pond backed up behind an actual beaver dam hidden in the reeds. The wary, nocturnal beaver is seldom seen and you will look in vain for the familiar beaver lodge, because Big Bend beavers make do with what the floodplain has to offer. Instead of building wooden houses, these rodents dig burrows in the river bank, foraying from there to feed on willow, cottonwood, seepwillow, and river cane. Around the turn of the century the Rio Grande and its main tributaries abounded with beaver, but fur traders trapped them to the brink of extinction, woodcutters and farmers destroyed their food supply, and cattle feeding in the canebrakes trampled their burrows.

It is hard to imagine just what destroying the trees and ground cover can do to fertile land and to a living stream, but a visit to Terlingua Abaja shows you. James B. Gillett, foreman of the famous G-4 Ranch, recalled that in 1885 “the Terlingua was a bold running stream, studded with cottonwood timber and was alive with beaver.” There was one grove of trees where he had seen at least 1,000 head of cattle enjoying the shade. But after the Terlingua mines opened, Mexican farmers established a community at Terlingua Abaja, a few kilometers up the creek from its junction with the Rio Grande. All the cottonwoods up and down the creek fell to construction and hungry mine furnaces and the virgin earth turned bottom up beneath the plow and grubbing hoe. Today this once fertile valley is a wasteland.

The Big Bend mosquitofish (Gambusia gaigei) has a miniscule geographic range. Not only is it restricted to the park, as some other species are, but it is also restricted to one pond. The fish was first identified in 1928 in Boquillas Spring. Unfortunately, the spring soon dried up and for some 20 years the fish was thought extinct. In 1954 more were found near Rio Grande Village. This group was later threatened, and a pond was built especially for the fish. But people dumped into the pond other fish that ate this tiny mosquitofish. At one point the world’s only survivors were two males and a female, Rio Grande Villagers that biologists had removed to a laboratory aquarium at the University of Texas at Austin. A cold winter again killed nearly the whole park population, and again the Austin-raised stock replenished it.Gambusia gaigeigives birth to live offspring and has been around as a species since mastodons. They feed largely on mosquito larvae.

Actual size

Since the coming of the park, cottonwoods have returned to the floodplain, especially at Castolon. A stately colonnade of eastern cottonwoods lures ladderback woodpeckers and yellow-bellied sapsuckers to Cottonwood Campground. More than 100 lanceleaf cottonwoods may be seen along the road that leads to Santa Elena, Mexico. Standing as much as 30-meters (100-feet) tall, refreshingly green in summer and gorgeous gold in fall, cottonwoods seek water by spreading horizontal roots far and wide, and by sending taproots deep down to the water table. They propagate in early summer by shaking millions of cottony seeds upon the wind. These fuzzy white parachutes may lie in windrows or cover the ground downwind like new fallen snow.

Along the River Road from Castolon to Santa Elena Canyon, you get another glimpse of what water means in the desert. The road winds along the edge of an alluvial bench from 15 to 30 meters (50-100 feet) high. Atop this terrace you have the widely spaced shrubs of the Chihuahuan Desert, but peer over the edge and you find a dense green wilderness crowded between the benchface and the river. All that separates lifeless sand from green jungle is the vertical distance that stops the water. Down there salt cedars have packed themselves thickly into the narrow space.

Another water-loving plant prevalent along the river and dry washes is honey mesquite, a feathery, thorned shrub- or tree-sized member of the pea family. Its root system, with a deep tap root, is so extensive that more wood lies underground than shows above ground, and natives say you must “dig for wood” here. Mesquite trees multiply as persistently as salt cedar, but are highly useful to man and to wildlife. Honey bees and butterflies visit the yellow mesquite flowers, quail roost in the branches, and wood rats collect mesquite beans in tremendous numbers. Deer, horses, and cattle also relish the beans, while Indians and early settlers made a nutritious bread from mesquite bean flour. Honey mesquite carries the standard Kentucky-wonder type of bean. But the screwbean mesquite ortornillo—for which Tornillo Creek was named—puts out a curious cluster of corkscrew-shaped fruit pods. Mesquites often mass together in thickets, and they do very well in the drier soils of arroyos, often rubbing thorns with acacias, a family of sweet-smelling, flowering trees and shrubs attractive to honey bees and hummingbirds. The roots of these thickets provide apartments for scores of floodplain pocket gophers, kangaroo rats, and hispid cotton rats.

A greenbelt along a wash contrasts sharply with surrounding desert habitat.

Despite the luxuriance and rapid growth of floodplain flora, life along the greenbelt rests in precarious balance. The floodplain is the one place in the park from which domestic cattle have never been successfully removed. The problem is that Mexican cows, horses, and burros do not recognize international boundaries.

There was a day when cows grazed grasslands at higher elevations, and before the cows could be seen herds of pronghorns, golden, graceful, large-eyed, with black horns and white rump patches. Imagine if you can how Tornillo Flat must have looked at the turn of the century with fine grasses bending under the wind and the pronghorns flashing their rump patches in sudden semaphore. Depending on speedy flight for protection, pronghorns seek wide-open places where they can see a long way off. Today, Tornillo Flat is a bald shrub desert. The pronghorns vanished long ago. The small band sometimes seen north of Tornillo Creek is the remnant of a herd reintroduced in the 1940s.

The grass that flourished on Tornillo Flat in its heyday was a very good clump-forming grass called tobosa. To the first settlers it looked as though there was more grass along Tornillo Creek than could ever be eaten off. Yet the tobosa soon disappeared, falling first to mowing machines and finally to the domestic herds that cropped it out of existence. Hay balers plied Tornillo Flat into the 1930s.

Grasses spread through seed germination, and in some cases by underground and aboveground stems. As a general rule, root depth equals the height of the grass, but half of the root system dies back each year. This is natural and even desirable since the dead roots create new soil and you still have a sound root system if the grass isn’t topped too much. But heavy overgrazing causes grass roots to die back even more and creates an abnormally shallow root system. This is doubly dangerous in desert country where heat and the need to search out water pose crucial problems for all plants. Nor is this all,because other good things come—and other good things go—with a healthy ground cover. As each year’s grasses die back they fertilize the soil and insulate seedlings and roots from the sun’s killing heat, but when this cover is reduced, good grasses disappear and poorer grasses take over. Surface conditions are finally so changed that neither grasses nor grassland forbs and shrubs can grow. Seedlings may burst into brief life with a rain but when the sun bears down again day after day the unprotected plants perish. With nothing to hold it the soft topsoil blows and washes away. Desert downpours soon gully the ground, changing drainage patterns and lowering the water table beyond the reach of short grass roots. Longer rooted desert shrubs move in, first the shortlived tarbush, and finally creosotebush. The result is seen on Tornillo Flat today: typical Chihuahuan shrub desert with sparsely scattered creosotebush and cactuses.

What happened at Tornillo Flat also happened to other park grasslands. Chino grama, ignored by cattle and goats, but relished by sheep and horses, is and was the dominant grass of the Big Bend foothills. By 1944, overuse had so stripped the grasslands near Government Spring that you could hardly find a bunch of chino on the bare beige hills. Even in the mountains proper the grasses had all but disappeared, and biologists conducting an ecological survey found that the South Rim looked and smelled like a goat paddock.

Once the park was established and domestic animals were removed, native grasses got the chance to reestablish themselves. At first nature itself blocked recovery. For seven long years drought ruled all life in Texas. When the rains finally did come, grasses improved at different rates in different places. They had the most difficult time at lower elevations where heat and aridity are greatest. Several attempts to seed Tornillo Flat have been made, but it may take decades for these once bountiful bottomlands to green again. Grasses in the grassland belt surrounding the Chisos have made a remarkable comeback, however. In ten short years ground cover increased 30 percent. Grasses at the higher elevations are now probably as rich as ever.

Furs were an active commodity in the Big Bend until about 1940. Beaver once abounded along the river and its tributaries. Both fur bearers and predators were taken. The bighorn sheep was largely extirpated, selling for a time as “Mexican goat.” Wolves were extirpated before the park could provide refuge. Not all species were trapped. The javelina was hunted during World War I, for use in gloves, coats, and suitcases. The bristles went into brushes. Elmo Johnson (photo) bought furs from trappers at his trading post. Good profits required a good eye for raw furs, which Johnson possessed. Furs not trapped during the animal’s winter prime were nearly worthless, and values depended on their condition generally. No fur market existed in Mexico, so furs trapped there were sold at Texas trading posts, destined for the fur houses in St. Louis, Missouri. Only a portion of Johnson’s fur stocks shows in this 1929 photograph. Furs were a good business for him, because trappers took their value in goods, his first profit in the transaction. He then sold the furs for his second profit. Later, salaried government trappers worked this area to control predators. Today, all wildlife in the park is protected.

Gray fox

Mule Deer

Bobcat

Kit fox

Coyote

Badger

Elmo Johnson and furs.

Different kinds of grasses have adapted themselves to different soils and altitudes and grow in company with different co-dominant plants. In colorful sequence the grasses create a three-dimensional mosaic that begins on the edges of the shrub desert, covering the foothills and running up through the woodlands out onto mountaintop meadows. You can see these differences quite easily.

The U.S. Boundary Survey trekking the Big Bend country in 1852 encountered this Lipan Apache warrior. His portrait came to adorn the survey report.

Let’s say it’s ten o’clock on a fine fall morning, and you are driving from Rio Grande Village up to the Basin. You find shrub desert all around you at first, with the usual creosotebush, ocotillo, and pricklypear. The only grass you see grows in a buff-colored strip on either side of the road, where runoff from infrequent rains creates a habitat moist enough for grasses to germinate and reach maturity. But after you pass 900 meters (3,000 feet) of elevation you begin to see the first sparse bunches of chino grama spotted here and there across the desert. Somewhere just below the Dugout Wells turnoff you find quite a bit of bunch grass among the bushes. Almost imperceptibly the chino thickens until at 1,000 meters (3,500 feet) the hillsides appear cobbled over with lumps the color of gray rock. It appears that you couldn’t step down without stubbing your toe against a clump of gray-green grass or lechuguilla. Soon all the slopes are patterned yellow and gray-green as solid stands of lechuguilla crowd into the chino grama. The grass is so thick now that scaled quail hunt seeds along the roadside and cottontail rabbits bounce jauntily across in the mid-morning sunlight.

The colors you see owe much to the angle of the sun, but at about 1,200 meters (4,000 feet), near Panther Junction, the plants themselves add a soft new hue, the beautiful silver-blue of ceniza shrubs. Bunches of vivid green grass crop up amid the tawny three-awns by the roadside, and the tops of the tarbush are brushed with yellow. Rock, gravel, grass, and shrub blend together in shades of tan, gray, green, and blue pinpointed by Christmas-red fruits on the guayacan, with once again vast gardens of chartreuse lechuguilla and skeleton-leaf goldeneye shrubs. These rolling grasslands have much less pricklypear and creosotebush, and they have a lower profile than the shrub desert. Here and there the Torrey yucca lifts its shaggy head high, but the whole land surface looks somehow smoother, less hob-nailed than before.

When you start the 11-kilometer (7-mile) climbtoward the Basin, chino grama gives way to a variety of grasses, blue, black, hairy, and side oats grama, and the straw-colored grass aptly named tanglehead. The whole color scheme changes with the grass from shades of gray to reddish brown and yellow, and the tops of these good grasses have the heavy headed look of grain. The lechuguilla becomes less obvious. Gradually the moisture-loving mountain shrubs push the grasses back from the roadside, but the golden gramas grow with wonderful abundance on the drier slopes beyond. Still higher, the still good grasslands are studded now with century plant, basket grass, and sotol.

Ancient rock art known as petroglyphs (top) decorate rock faces. The arid climate protects them.

Mortar holes deepened imperceptibly each time the Indians ground seeds or grains in them.

Earlier in this century sotol abounded between Green Gulch and Government Spring, but in the severe drought during World War I, ranchers chopped it out for cattle feed. Today you will find a perfect forest of sotol growing at Sotol Vista on the western flank of the Chisos. As you can see from the overlook, this narrow-bladed plant favors the cooler north-facing exposures. Sotol leaves grow at ground level from a short trunk, and nearly every spring the plant thrusts up a brush-like bloomstalk, 4 to 6 meters (15-20 feet) tall, covered half its length by greenish-white flowers. Prehistoric Indians had many uses for sotol, and later the Chisos Apaches often located their rancherias at solid stands of “desert candle.” They used the fibrous leaves in making mats and ropes, fermented a potent drink from the pineapple-like heart, or roasted it in rock-lined pits as we roast beef. Several crumbling sotol pits are found throughout the Chisos, and sotol still serves as an all-purpose plant along the border.

Sotol is one of those Big Bend plants that has its very own grasshopper. If you look closely, you may find a little fellow feeding high on the bloomstalk and looking for all the world like a bud. He lives his whole life on the sotol plant and knows just how to use it to advantage. If you annoy him he will probably play possum, drawing in his legs and dropping like a stone right down into the thick of the sotol leaves. Few predators come away unscathed from a close encounter with those saw-edged blades.

Evidence of Paleo-Indian culture dates back to about 9000 B.C. here. The Archaic and Neo-American culture sites date from about 6000 B.C. These occur near today’s water sources, so climate conditions then were probably similar to now. The Archaic people used the atl-atl, a dart-pointed throwing stick, to hunt game animals. The Neo-Americans used the bow and arrow. Spaniard Cabeza de Vaca encountered their descendants in his 1535 expedition through the area. In the 1640s the major Indians here were the Tobosas, Salineros, Chisos, and Tepehuanes, who fought Spanish encroachment and enslavement. Spanish horses enabled the Mescalero Apaches to expand their range and dominate the area by the 1740s. They became the Chisos Apaches. By the 1840s, the Comanches, also with Spanish horses, dominated an enormous range focused on the Big Bend. When Texas was annexed by the United States in 1845, the U.S. military became the Indians’ antagonist. Forts strung along the route to California goldfields after 1849 sliced the Indian territory in half.Retreating far into the mountains, the last Apaches, under Chief Victorio, were defeated by Col. Benjamin H. Grierson and scattered into Mexico. There Victorio was soon killed by Mexican troops. Col. William H. Shafter continued the Army’s Indian pacification after March 1881. Not all Indians were hostile. The painting, by Capt. Arthur Lee, shows West Texas Indians trading at Fort Davis.

Retreating far into the mountains, the last Apaches, under Chief Victorio, were defeated by Col. Benjamin H. Grierson and scattered into Mexico. There Victorio was soon killed by Mexican troops. Col. William H. Shafter continued the Army’s Indian pacification after March 1881. Not all Indians were hostile. The painting, by Capt. Arthur Lee, shows West Texas Indians trading at Fort Davis.

Chief Victorio

Col. William H. Shafter

West Texas Indians trading at Fort Davis.

Another lily of the desert is the yucca. Overabundance of this perennial often indicates abuse of a grassland, and yucca gradually thins out again once a good grass cover is reestablished. Several species of yucca flourish in Big Bend. Most widely scattered is the Torrey yucca or Spanish dagger. Seen from desert lowland to mountain top, it thrives at Persimmon Gap near the park’s north entrance.

One of six yucca species in the park, the giant dagger abounds in Dagger Flat. It blooms every two or three years from late March through April.

Yucca grows like sotol from a central trunk, but it adds new growth at the top and lets its dead leaves drop down in a palm-like grass skirt. The yucca also puts up a bloomstalk year after year, and the creamy flowers are a favorite browse of deer and cattle. Yuccas may live from 50 to 75 years, reaching tree-like proportions. The giant dagger that gives Dagger Flat its name may grow more than 6 meters (20 feet) tall. In good years it blooms around Easter-time, and a single bloomstalk may have more than 1,000 flowers and weigh as much as 30 kilos (70 pounds). Indians used nearly every part of the yucca in countless ways. They ate the flowers and fruit, wove baskets and made brushes from leaf fibers, and made soap from the roots. Along the border, natives still harvest the great yucca flower-heads and feed them to livestock.

The Mescalero Apaches roasted the mescal or century plant using the same technique they used for sotol. The mescal was as central to the Apache way of life as the bison was to the plains Indians. They made food, drink, medicine, mats, ropes, bags, and even needles and twine from the great, gray-green agave.

It is not true that the century plant takes a hundred years to bloom; it’s more like 25 to 50 years. Once started the bloomstalk shoots up at the rate of nearly 2.5 centimeters (an inch) in an hour, or up to 41 centimeters (16 inches) in 24 hours. Soon platters of golden flowers float on the air, and bees, flies, and ants come to the feast. The violet-throated Lucifer hummingbird may sometimes be found at a mescal in blooming season. At night the Mexican long tongued bat leaves its cave on Emory Peak and comes to feed on the nectar and ample pollen.

Like all agaves, the mescal expends its strength on this onetime burst of blooming. Once the seed pods form, the plant dies and young plants arise near its base. But that is not the end of its beauty or its usefulness. If you climb the foot trail to Juniper Flat through the thickly grassed woodlands above the Basin, you will pass more than one dead mescal with its towering bloomstalk supported by the limbs of some pinyon pine. Year by year, in graceful andgradual decay, the agave leans in its neighbor’s embrace. As it slowly splits up, it dresses the pine in a flowing drape of fiber fragments. You can see little wormholes here and there, and larger holes where woodpeckers have taken a meal. This life-supporting return to dust goes on all over these mountains.

The century plant took its name from the erroneous notion that it took 100 years to bloom. It takes “only” 25 to 50 years. Then the plant dies.

Many of the park’s finest grasses may be found in the mountains, for while the grasslands blend into the woodlands somewhere around 1,700 meters (5,500 feet), the grasses continue all the way up to the mountaintops. Again, the species change with climate, altitude, and ground cover conditions. The beautiful bull muhly favors north-facing slopes, and, growing in clumps up to just over a meter (4 feet) high, it helps hold soil on the hillsides. With its large purple flowering heads, it makes a good bedding grass for deer. So does the golden thread-leaf stipa that likes to grow under juniper trees, spilling its long blades in rounded clumps.

Since the return of the grasses the mountains and foothills both support a fascinating host of grassland animals. Some, like the yellownosed cotton rat, have come back with the grass. Many of these grassland creatures are abroad at night and are best seen at dawn and dusk. Even after dark you may see a great deal of life along the highway. The 16-kilometer (10-mile) stretch between park headquarters and the Basin may bring startling glimpses of grassland activity within reach of your headlights: a great horned owl with its catlike face and “ears,” sitting still as a sphinx in the middle of the road; a coyote pair gamboling like shepherd pups, their paired eyes flashing white and bright as automobile headlights. These carnivores have come to hunt the rats and rabbits making a mad dash across the road. Arthropods and snakes come to the pavement to warm themselves. The diamond sparkles that litter the blacktop may be reflections from spiders’ eyes. You see a blood-red coal of fire spring to one side at the edge of the road and then as abruptly as a UFO leap 3 meters (10 feet) straight-up into the air. A ringtail climbing a tree perhaps? Or a poor-will taking flight? A flash of pink lights at elbow and shoulder height turns out to be a mule deer and fawn. Stop, turn off your own lights, and look and listen and you will behold a world as it must have been a long time ago, singing in the silence underneath the stars.

When the deepest channel of the Rio Grande became the boundary between the United States and Mexico in 1848, the Army assumed a thankless task: To enforce an invisible boundary in impossible terrain populated—if at all—by people traditionally disposed to crossing the river freely. At times the Army depended on the Texas Rangers. During the Civil War era troops were withdrawn from the Big Bend, and border incidents surged. After the Mexican revolution of 1910 that government lost control of its northern provinces. Bandit gangs plagued both Texas and California. Pancho Villa used border forays to create tension between Mexico and the United States. In 1913, raiding bandit Chico Cano was capturedand freed by his gang in an ambush; the next year he killed his Customs Service captor. Cano was photographed with 8th Cavalry Major Roy J. Considine in 1918. Three soldiers and a small boy were killed in a 1916 raid on Glenn Springs led by Navidad Alvarez, a lieutenant of Pancho Villa. The store was looted and houses burned. Livestock raids on ranches sometimes left entire families murdered. Many Texas Rangers were killed in ambush over the years. Smuggling activities abounded. Arms and ammunitions passed into Mexico, and liquor (during prohibition) and silver bullion passed into the United States.

Chico Cano and Maj. Roy Considine.

Bandits on horseback.

The Chisos float in morning mist after a rare ice storm.

From a distance the Chisos Mountains don’t look wooded. They seem to be sculpted from naked rock. Even as you begin the drive up Green Gulch you expect to see only buffy grass, century plants, and sotol. But as you pull abreast of Lost Mine Peak the grass is gone from the road’s edge and the shoulders are covered more and more thickly with green, leafy shrubs. Soon you see taller bushes on the open slopes, the evergreen sumac, Texas madrone, cat claw, and common bee-balm, crowned with beautiful deciduous and evergreen leaves.

The Chisos Mountains fascinate for so many reasons: their great beauty, their wooded coolness and greenness, the exceptional variety—and rarity—of plant and animal life. Lying close to the border, they encompass an interesting blend of U.S. and Mexican species. But because they stand alone and apart, they support species found nowhere else. And their height creates a temperate environment, a grassed and timbered island in a sea of rock and sand.

In the Chisos as elsewhere in desert country, what lives where depends on highly local conditions of soil and climate. While daytime temperatures in the mountains average significantly cooler than the desert flats, and while rainfall in the Basin is twice as heavy as at Rio Grande Village, just as crucial are the land’s shape and the sun’s angle. You might expect that trees grow as a woodland belt around the mountains, with treeline determined by altitude. Not so. Many trees prefer canyons to exposed slopes because soils are deeper there and drainages offer more water. Even in the same canyon, more trees may grow on cooler north-facing slopes, while grasses predominate on sunny south-facing slopes. Or pinyons, junipers, and oaks may flourish at lower elevations, while most other forest species occupy the canyon’s heights.

At about 1,400 meters (4,500 feet) of elevation as the mountains begin to close, a surprise delights theeye: The first of what you might call trees beside the road. Suddenly, masses of trees—junipers, little oak trees, and pinyon pines—higher up in the drainages that crease the mountainside. And multitudes of woodland birds dart in and out of the trees and bushes along the roadway. You understand now why they call this valley Green Gulch. As you approach the first water tank you are in actual woodland. Grasses still grow on the open slopes along with bushes and pricklypear and sotol, but here are the first easily distinguished little pinyons beside the road. At 1,600 meters (1 mile) of elevation they are fairly respectable pines. Tree cover increases and, after the second water barrels, the woodland comes right down to the road. The grass is less obvious now, but it covers the ground between the trees and is especially thick on south-facing slopes. Flocks of little birds fly up from the road ahead of you. At the switchbacks in Panther Pass you peer up the steep slopes at solid stands of deciduous green trees set off against darker evergreens. Way up at the top leap scarlet flames of frost-touched Grave’s oak and fragrant sumac.

These pinyon-juniper-oak woodlands are pretty typical of the dry Southwest. Chisos woodlands include only one pine, three junipers, and many varieties of oak. You can easily identify pinyon and juniper trees, but the oaks are often hard to tell apart because they tend to hybridize. The different tree species have different soil and water requirements and where moisture is harder to come by they grow smaller and more widely spaced. You’ll find redberry juniper at drier, lower elevations, such as Green Gulch. This is a rather scraggly shrub or small tree whose lower branches often touch the ground. It has scale-like yellow-green leaves, and red berry-like cones. It will often invade abused grasslands. The gray oak, an evergreen with small olive-green leaves and dark gray bark, also prefers drier soils. On exposed slopes it too takes on shrub-like proportions but grows to 20 meters (65 feet) in protected canyons. Birds, peccaries, and deer feed on gray oak acorns. The Indians preferred the acorns of the Emory oak.

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