NATIONAL PARK SERVICE Sonoran Desert National Park, Arizona: A Proposal

Plants and Animals

The rich and varied vegetation is perhaps the most striking feature of the Sonoran Desert — certainly it is the most obvious and of most interest to the visitor. Within the study area three biological subdivisions of the Sonoran meet and blend together. As a result there is a great variety of plant and animal life, including many species rarely found anywhere else in this country.

Special symbol of the Sonoran Desert is the saguaro; it grows naturally nowhere else. This gigantic single-stemmed cactus, standing 10 to 50 feet high, forms weird open "forests" of gaunt, fluted, olive-green columns, often with fantastically extended arms. In many places the saguaros spread over hill, valley, and mountainside in groups, ranks, and clusters, making as uncanny a landscape as can be seen anywhere.

But perhaps the most remarkable characteristics of the saguaros is that they dominate a little world of their own, which has a particular animal, bird, and plant life. Many species are unique to the Sonoran Desert and are found nowhere else, and the ranges of some are almost identical to that of the saguaro. The local Indian cultures, from the dim past to the present time, are also based upon the saguaro, and the primitive native way of life still persists little changed, with religion, customs, and well-being directly influenced by this giant cactus. The Indians make the fruit into food and drink; use the ribs for their huts and ramadas; and weave saguaro fiber baskets and drinking vessels. So important is the saguaro to the aboriginal inhabitants, that they celebrate their New Year when the fruit ripens in May.

However, the whole Sonoran Desert is preeminently a land of cactuses, and scattered among the giants are dozens of other species, as well as a surprising variety of other plants, mostly bristling, spiny, or spiked. Besides the saguaro, organpipe, and senita, there are the barbed barrel cactus and night-blooming cereus, the many-branched tree cholla and fuzzy teddy bear cholla, pricklypear, rainbow, fish hook, and a host of ground-hugging cactuses.

Also numerous are trees and shrubs, such as the green-trunked paloverde, the whiplike ocotillo, the leafless crucifixionthorn, the fat trunked elephanttree, creosotebush, centuryplant, mesquite, ironwood, catclaw acacia, bursage, smoketree, desertwillow, and several varieties of yucca.

In early spring, especially after generous winter rains, the desert stages a gaudy flower show. In places valleys and hillsides are spread with rainbow-hued carpets of blooms. Then, if summer thunder showers are plentiful, the land comes to vigorous life again with a second wildflower exhibit and scattered patches of green grass, in places almost as lush as the Vermont countryside. Prominent spring and summer flowers are the Mexican goldpoppy, magenta, owl-clover, blue lupine, and bright orange mallow.

The Sonoran Desert teems with animal life, from earthbound insects, mammals, and reptiles, to soaring eagles, hawks, and buzzards high in the sky. Familiar birds include the roadrunner, gila woodpecker, cactus wren, gilded flicker, inca dove, and elf owl. In addition to pronghorns, bighorn sheep, and peccaries, the larger animals include the ubiquitous coyotes, as well as cougars, bobcats, badgers, foxes, and mule deer. But perhaps most fascinating is the busy life of the smaller creatures who run, hop, crawl, burrow, and climb in well-adjusted association with the desert vegetation. Nowhere can be found better examples of adaptation to an austere environment of extreme aridity. Every living thing is provided with special ways and means of survival, and this almost waterless community of plants and animals induces a feeling of reverent awe for Nature's infinite capacity.

All in all, the Sonoran Desert is a place of beauty, scientific interest, and relaxation. It is a priceless legacy from our original natural heritage and, as such, is of national significance. As much as possible of what remains in a near-primitive condition should be preserved intact, for the enjoyment, education, and inspiration of the crowded generations to come.

Geology

The broad landscape of the study area is of comparatively recent origin. However, the elements that compose it are venerable even on a geological time scale. The outline and form of the present mountains and valleys date back only a few million years, but the structural materials and chain of events which made the country what it is show a continuous tectonic history spanning at least a half-billion years, possibly twice that long. Through the ages the land periodically rose and fell, and several times was the bed of shallow seas. Mountain ranges were uplifted and eroded away. Sedimentary layers were formed from the wasted mountains, and vast amounts of molten magma were intruded beneath the earth's surface to become the basic crystalline rocks of today.

The late Tertiary Period, some 15 to 20 million years ago, was a time of widespread volcanic activity, and much of the area was buried by successive lava flows and showers of ash which filled the valleys to depths of hundreds of feet and, in places, built up veritable mountains. This tremendous overburden of volcanic material came from no single center, but was poured forth from dozens of vents throughout the area. By the end of the Tertiary the subterranean fires died, the final lava flows hardened into andesite, rhyolite, and basalt, and the stage was set for the modern geological drama.

Its first act began with orogenic upheavals, and the present fault-block ranges were slowly uplifted along northwest-southeast trending zones of weakness. As they rose they carried the volcanic covering up with them. This lava cap can still be seen atop the crests and on the flanks of the Ajo Range and the Puerto Blanco Mountains in Organ Pipe Cactus National Monument, and the Growler and Cabeza Prieta Mountains in the Game Range. Other indications of Tertiary volcanism are lava plugs, buttes, and mesas throughout the area. However, the Granite and Mohawk Mountains and the Sierra Pinta in the Game Range have lost their lava overburden and now consist almost entirely of the original underlying granites, schists, and gneiss.

Little sedimentary rock remains, but one strikingly eroded formation of reddish sandstone rises to the east of Tule Well, near the Mexican border. The valleys, and the bajadas leading up to the bases of the mountains, consist of outwash alluvium and detritus to an unknown depth. But whatever the thickness, it is impressive that such a tremendous amount of material can have come from mountain ranges of such limited extent and modest altitude. In fact, the results of past and present geological forces are such prominent features of the area that even the layman finds them challenging subject for speculation.

The last act, perhaps most dramatic of all because so recent, was the pouring forth of the Pinacate volcanic field, over the line in Mexico. It would be safe to conjecture that if the Gadsden Purchase had included more land to the south in the United States, the Pinacate region today would be one of our most remarkable and best known National Parks. Here "hell boiled over," not once, but countless times. Centered in the round-topped Sierra Pinacate, 3,957 feet elevation, remnant of a larger and higher volcano, an apron of multiple lava flows spreads for many miles in every direction. The northern edge spills northward over the border into the Cabeza Prieta Game Range and, to the west, the lavas are buried beneath the great sand dunes which extend along the Sonora shore of the Gulf of California for more than 100 miles. Incredibly rough, barren, and desolate, the dark, scabrous expanse is punctuated by hundreds of cones of every size and age. Some are battered and worn, others fresh as if they had erupted the day before. Almost every kind of volcanic phenomenon known on earth can be found here.

But the most spectacular features of the Pinacate region are the nine gigantic calderas directly incised without cones in the peripheral lavas to the north and northwest. Largest are MacDougal Crater, Cerro Colorado, and Crater Elegante. The last is nearly circular, measuring approximately 4,800 feet in diameter, and about 700 feet deep.

The first major activity in the Pinacate volcanic field occurred at the beginning of the Pleistocene Epoch, perhaps more than a million years ago. The last eruption, probably at Cerro Colorado, dates back only about 1,000 years, plus or minus a few hundred. During the region's short recorded history Pinacate has been quiescent, but it cannot be assumed that the field is dead for all time.

Myriads of diverse forces are continually shaping the landscape day after day. Their actions are, of course, generally far too slow to be measured by human clocks, but at any time the curtain may rise on another act in the everlasting geologic drama.

Prehistory and History

For thousands of years southern Arizona was inhabited by ancestors of the present-day Indians. Although the climate was considerably cooler and more moist than it is today, there is no evidence that these early Indians made permanent settlements within the study area.

In later times, when conditions were much as they are now, the territory was the home of a few families of seminomadic Indians, known as the Sand Papagos. These primitive people eked out a meager living in the harsh desert environment by hunting bighorn sheep and subsisting on what other food they could find — mainly cactus fruit and mesquite beans.

Well-worn trails, still clearly visible in many places, cross the study area from southwest to northeast. These were part of a general Indian trade route from the Gulf of California into the interior. Salt and sea shells from the Gulf were particularly popular items of barter with these people, and were eagerly sought by inland tribes. Along the trails are the remains of "sleeping circles" outlined by boulders, stone shelters, metates, petroglyphs, and other relics of a vanished culture. A popular resting place on one of these routes was at the present Charlie Bell Well, then presumably a copious spring, near the northeastern corner of the Game Range. There, scores of petroglyphs can be seen on the rocks scattered over a hillside above the ancient camp. The much larger spring at Quitobaquito in the southwest corner of the Monument was an equally important stopping place on another well-used trail.

When recorded history began with the coming of the Spaniards some four centuries ago, the Growler Mountains were the dividing line between the Yuma Indians on the west and the Papagos to the east and southeast. The latter were finally awarded a part of their ancestral homeland in perpetuity by the United States Government in 1916, with the establishment of the Papago Indian Reservation. Containing approximately 2,775,000 acres, it is the second largest Indian Reservation in the country and is now inhabited by about 10,000 Papagos. Their principal basis of economy is cattle raising. The tribe is an interesting example of acculteration, combining both the old and the new. These Indians have adopted what they want from modern civilization, and are largely Roman Catholics, but they prefer to live in native-style villages and rancherias, and stoutly cling to their time-honored way of life.

The first white man to enter the region was the Spanish explorer Melchior Diaz, who crossed it in 1940 on his way to the mouth of the Colorado River. A century and a half later the country was often traversed by the famed Jesuit missionary priest Father Eusebio Kino, who was one of the Southwest's outstanding explorers and a pioneer emissary of European civilization to its native population. He established one of his many Indian missions at Sonoyta in 1699, and his meticulous journals record stops at Quitobaquito, Heart Tank, Cabeza Prieta Tank, Tinajas Altas, and other places in the study area. Father Kino is credited with making the first maps of Pimeria Alta, the name then applied to southern Arizona and northern Sonora, and with the discovery that California is not an island.

In 1774 the indomitable Franciscan Padre Francisco Garces and Captain Juan Bautista de Anza passed through the southern portion of the study area. Two years later they repeated the journey accompanied by more than 200 colonists for the founding of San Francisco. Their route later came to be known as El Camino del Diablo, or the "Devil's Highway," because of the great numbers of humans and animals who perished along it from fatigue and lack of water. Many gold seekers followed this hellish track westward in the late 1840's and 1850's and it is said that at least 400 of them died along the way. All this region was Spanish until Mexico won its independance in 1822. Then, with the Gadsden Purchase of 1854, the United States acquired 45,535 square miles of Mexican territory, and the present international boundary was established.

In spite of its early exploration, the country was too inhospitable to invite settlement, and it remained largely an unpopulated desert. The entire region has been thoroughly prospected, but no rich strikes were ever made with the exception of the great copper deposits at Ajo. Spaniards worked mines in the vicinity as early as 1750, but intensive development did not begin until 1854. Today the Phelps Dodge Corporation conducts a large open-pit operation and smelter, ard the Ajo area is one of the most important mining districts in the Southwest.

Unquestionably few sections of the United States have had such a long human history, yet still remain so remote, sparsely settled, and little known. This, of course, contributes greatly to the region's attractiveness, and should be taken into account in any discussion of its future status. Such intangible considerations should also be a predominant factor in planning for public use of the area.