Life in Colorado has been shaped, more obviously than in most States, by great natural features and characteristics. Wide differences in topography, geology, types of soil and vegetation, altitude, temperature, length of growing seasons, and annual rainfall mark this diverse land of floor-like plains, battlemented mesas, and jagged snow-capped peaks. The problems and concerns, the everyday routines, perhaps even the philosophy of life of miners isolated in the rock-ribbed mountains are naturally not those of ranchers on the high, dry, sandy plains, and the life patterns of both differ in turn from those of farmers carefully grooming broad green acres in the sheltered river bottoms. But whatever else concerns them, all share one persistent and often anxious thought.

"Is it going to rain?”

"Do you think we'll have snow?"

To Coloradoans, weather is not a conventional subject, a means of just passing the time of day, but a very serious matter. Want of snow on the high ranges in February, an unseasonal dry spell in May, can— and often does—spell the difference between a fat and a lean year, for water is the base of the State's present economy and the key to its history as well.

Up its watercourses came Spanish, French, and American explorers. After them came the Mountain Men—Jim Bridger, Kit Carson, Jim Beckwourth, Jim Baker, "Broken Hand" Fitzpatrick, "Uncle Dick” Wootton, and many another trapper and trader of almost legendary fame. All these kept close to the streams, tracing them to their sources in search of beaver and other peltry so that milord in London—and in Paris and New York, too—might appear resplendent in a white beaver topper. With the decline of this curious trade linking the farthest frontier with the distant world of fashion, gold conjured up a human flood that swept across the plains and into the mountains. Gold-hunters, too, kept close to the streams, for without water they could not wash "pay dirt" in pans and sluices, could not operate stamp mills and smelters. And water, like a magic fountain, has ever run through the day dreams—and at times, unfortunately, like an elusive phantom through the nightmares—of cowmen, sheepmen, beet growers, hay ranchers, truck gardeners, and general farmers.

Where there is water, there is life, as Coloradoans well know. To expand the habitable area within the State, they early put their wits to work contriving vast irrigation projects to water millions of acres of potentially fertile land. Coloradoans have improved upon Nature, but as even a cursory glance at the configuration of the State discloses, the latter strictly conditions all development and sets its terms, imposing limits that cannot be transcended.

Colorado, "the barrier that became a goal," straddles the Continental Divide, the great ridgepole of North America, about midway between Canada and Mexico in one direction, and the Mississippi River and the Pacific Ocean in the other. Laid out with no regard to natural boundaries, a surveyor's dream, the State forms a perfect rectangle with its sides running true to the cardinal points of the compass, extending almost four hundred miles from east to west, somewhat less than three hundred from north to south. With 103,948 square miles, some 66,340,000 acres, twice the area of England and twelve times that of Massachusetts, Colorado is the seventh largest State; significantly, it ranks seventh from last in water area.

Quite as important, Colorado has a third dimension. Between its lowest and highest points, both along the Arkansas River, the first at Holly (3,385 alt.) on the Kansas Line and the other on Mt. Elbert (14,431 alt.), the difference in altitude totals 11,046 feet, or more than two miles. Of the eighty peaks in North America that soar to heights of 14,000 feet or more, Colorado has fifty-one—certainly the lion's share. Pikes Peak (14,110 alt.) is perhaps the most spectacular, rising abruptly as it does from the plains and not from the shoulders of other mountains, but it is not, as so many believe, the State's loftiest summit, ranking twenty-eighth. With 1,500 peaks rising 10,000 feet or more, Colorado has a mean altitude of 6,800 feet, exceeding that of any other State. This is not just another "interesting" fact—one more ''first" to boast of—for it profoundly affects temperature, growing seasons, rainfall, and consequently all forms of life.

Colorado, too, has a fourth dimension. Miners in isolated mountain canyons, with a limited vista of rocky crags and the merest patch of sky, are not much interested in the great sweep of the plains or the broad expanse of the mesa country. Nor is the miner much interested in the average or particular height of his mountains. But he and all dependent upon him for a livelihood—and they are many—have a vital and engrossing interest in the State's fourth dimension, the depth of its mineral resources.

Down the middle of the State winds the Continental Divide, splitting it into two roughly equal sections, the Eastern and the Western Slope, geographically and even economically distinct. South from Wyoming the Divide follows the crest of the Park Range, turns sharply eastward along the Rabbit Ears for fifty miles, then turns as sharply southward along the Front or Rampart Range through Rocky Mountain National Park and the glacier country. Angling southwestward to the high Mosquitoes, "that highway of frozen death" in boom days, the Divide boxes in the headwaters of the Arkansas and follows the towering Sawatch and Collegiate Ranges to the lower Cochetopa Hills, the watershed between the basins of the Pacific-bound Colorado River and the Gulf-bound Rio Grande. Again ascending, it runs up and over the precipitous San Juans to descend along its lesser ridges into New Mexico. Pikes Peak and Longs Peak, as well as Evans, Blanca, La Plata, Shavano, and many other of Colorado's highest summits, stand apart from the Divide.

But Colorado, contrary to popular belief, is not entirely mountainous. Broken only by occasional sand hills and isolated buttes, vast stretches of it are as smooth and level as a tidal flat, which is what they were, in fact, in the far distant past. Emerging gradually from the true prairies of Kansas and Nebraska, the high plains slope gently upward some two hundred miles to the base of the foothills. Northeast across these plains angles the South Platte; southeast, the Arkansas. Between their fertile and intensively cultivated valleys, bright green ribbons threading a brown expanse, lies a huge dry farming area, crisscrossed by thousands of miles of barbed wire, checkered with farms, dotted here and there with the green oasis of a prairie hamlet shading itself from the blistering sun under trees as carefully transplanted and lovingly tended as garden flowers. Rainfall here is scant, seldom attaining the annual State average of 16.62 inches. Winds are high in spring, and now and again a tornado has whirled its terrifying course across these plains homesteaded by sturdy hopefuls two or three generations ago. Nature in one of her more amiable moods favored them for a time; in recent years, however, they and their descendants have suffered the ravages of severe drought. But these weather-beaten plainsmen, bred to the earth, continue to grow crops and graze beeves in spite of drought, wind, insect plagues, occasional devastating hailstorms, and the now lessening menace of dust—"black snow"—to their fields.

A marked change occurs where plain meets mountain. The terrain abruptly begins to roll and swell upward. Dark evergreen forests, with some cedar here and there, creep down the slopes to terminate in a sharp line at the plains. Here along the base of the foothills, within a band some thirty miles wide extending from Wyoming to New Mexico, live two-thirds of all Coloradoans. With the exception of Grand Junction, far down the Western Slope near the Utah boundary, this narrow strip contains all of the State's cities of 10,000 or more — Fort Collins, Greeley, Boulder, Denver, Colorado Springs, Pueblo, and Trinidad—with many thriving smaller cities and towns between. Denver alone shelters more than a fourth of Colorado's 1,035,791 people, and with Colorado Springs and Pueblo, considerably more than a third.

Within this band is concentrated the State's commercial and industrial activity: vegetable canning plants, meat packing plants, coal mines, steel mills and forges, stockyards, large wholesale and retail houses, factories of many kinds, and most of Colorado's eighteen beet sugar refineries. This north-south population band is curious, for main lines of traffic and travel have always followed an east-west course and still do. The explanation again is—water. These communities along the foothills are strategically placed to tap the larger mountain streams as they debauch upon the plains, and the valleys of these streams provided the easiest routes in early days for the highly profitable distribution of supplies to boom camps in the mountains.

Down the middle of the State, behind the front ranges, stretches a chain of four large parks, great level expanses rimmed by snow-capped peaks. In North Park, a circular basin opening into Wyoming in the north-central part of the State, are the headwaters of the North Platte. Directly south, across the Continental Divide, is Middle Park, through which the Colorado, the State's largest river, flows westward toward the Pacific. Farther south, again across the Divide on the Eastern Slope, lies South Park, the Bayou Salado of the Mountain Men, a favorite hunting ground of the Ute, a broad and beautiful mountain meadow at the source of the South Platte. These grassy basins, with little or no timber, have been cut up into farms and ranches for the most part, and life here is rather in the plains than the mountain mode.

Midway along the southern boundary, traced by the Rio Grande as it flows sluggishly toward New Mexico, is a large triangular park known as the San Luis Valley, once the bed of an inland sea, a naturally arid but widely irrigated section, its adobe villages and scattered jascals the center of Spanish-American culture in the State. These villagers are descendants of the free Spanish settlers who followed the triumphal march of the Conquistadores, or of the retainers brought along by the haciendados who divided up the Southwest in princely demesnes under the seal of the Spanish and Mexican governors at Santa Fe.

West of the chain of parks the mountains shelve off into the mesa country that stretches away toward the purple sage flats along the Utah boundary, a beautiful but often sterile land inhospitable to man and beast. Through the mesa country flows the Colorado and its chief tributary, the Gunnison, both lined with fields and orchards on their lower reaches. Between them, almost at the point of their confluence in Grand Junction, looms the huge mass of Grand Mesa, rising 10,000 feet to a vast table top, the largest in Colorado. The lower surrounding mesas are heavily forested, for the most part, and on these and in the more remote valleys between them are the last strongholds of the cattle barons in Colorado. The scene here has changed little since the 1880's. Only a few roads have been improved; and down them, in place of bouncing buckboards behind a plunging span of cayuses restive in harness, rattle dust-encrusted automobiles of ancient vintage, as brown as the sun- and wind-burned faces of the cowmen at the "reins," in boots, spurs, Levi's, and ten-gallon Stetsons. After a day in one of the valley towns they load up their "wagons" with supplies and go snorting back up the grade to the "corral," not to be seen again for several months.

In the northwestern corner of the State are two great and still almost inaccessible river gorges, along the Yampa and the Green, tributaries of the Colorado. Here, in wild and fascinating country recently included within the Dinosaur National Monument, is Brown's Hole, a favorite rendezvous of the Mountain Men when beaver was king, later the hideout of cattle rustlers, highwaymen, and bank robbers.

The southwestern corner of Colorado, ringed by the high and precipitous walls of the San Juans, San Miguels, and La Platas, is occasionally cut off from other parts of the State for days at a time during winter months when heavy snows pile up in drifts thirty feet high in the steep narrow passes. In this corner is the breath-taking mesa country once peopled by the Cliff Dwellers, those accomplished Indians of an early pueblo culture who suddenly and mysteriously vanished some seven centuries ago. Their elaborate and often quite beautiful "apartment houses," built in natural caves high up on sheer canyon walls, dot the region and extend into neighboring States. The more important ruins in Colorado are now preserved and protected in Mesa Verde National Park, Yucca House National Monument, and Hovenweep National Monument on the Utah boundary. This is still Indian country, for here is the Consolidated Ute Agency, the only reservation in the State, a narrow arid strip inhabited by the eight hundred descendants of Colorado's once most numerous tribe, which held the whole mountain country as its range.

Tucked away in mountain pockets throughout the State are many old mining towns, all much shriveled since their lusty youthful days. Many are true ghost towns, having long since been abandoned. Yet the lure of gold is as strong as ever in the decaying camps, for old sourdoughs have never lost faith in the mountains, knowing well that their manifold hidden treasures have scarcely been touched.

And there is more than gold, or silver, or coal and oil, or zinc and molybdenum, in "them thar hills." There are crystalline streams with a sparkle brighter than the brightest ores, stocked with flashing rainbow trout, and Eastern brook, Loch Leven, cutthroats, and German Browns. There are great silent forests of lodgepole and yellow pine, pinion, Douglas fir, and blue spruce, for along the mountains runs the broad timber belt of Colorado. Most of it is now set aside in State and national forest reserves; national forests alone cover almost a fifth of the State. Here in this forested mountain country, much of it still a primitive wilderness of magnificent beauty, are the renowned playgrounds of Colorado, enjoyed alike by "natives" and their many guests, who in season all but outnumber their hosts. This yearly invasion of their haunts does not much bother old-timers in weathered mining camps and on remote mountain ranches, although occasionally they can be heard grumbling among themselves at the intrusion as they reminisce about the days "when Colorado meant gold, silver, and cattle, instead of tourist camps, dude ranches, and irrigated farms."

Along with this love of the glamorous old order, their children have inherited "the look of eagles"; they walk with the free stride of the mountain-born; they are a proud and self-sufficient lot; they ask no favors—and seldom receive them. But they are a hospitable folk, for their hospitality has been handed down as a tradition from the days when the only cardinal sin in the mountains was to refuse a stranger welcome.

Colorado has not always been a sharply serrated mass of prairies, plateaus, and soaring peaks. For millions of years in its distant past it was a level plain in its entire extent. In time it became a series of vast plateaus, later broken by cataclysmic upheavals that leveled some to prairies, buckled others into tower ranges. At least four times Colorado has been wholly or partially submerged by invasions of the sea that reduced it to a waste of shifting islands and muddy ocean bottoms. A score of times the land broke under the pressure of vast crustal warpings or was split by volcanic explosions. Droughts turned new land into deserts; fern forests overran the deserts and perished in turn under new droughts or marine invasions. When the seas subsided for the last time, dense subtropical jungles covered what are today grassy plains and snow-capped peaks. Ice sheets crept down from the north and then retreated. Meantime, through all these changing scenes, animal and plant life inexorably continued to evolve slowly from simpler to more complex forms.

At the beginning of the Paleozoic era, some five hundred million years ago, Colorado was a uniform plain leveled by the long erosive processes of the preceding Algonkian era, as was true of the entire Continent. From time to time vast sheets of water swept over the levels, and the geological history of the State during the three hundred and thirty million years of the Paleozoic era is largely a record of the changing relations of land and water. As the seas rose over the old continental shore lines, they invaded Colorado, first from the northwest, then from the southwest, while decayed mantle rock spread as mud along the retreating or advancing coasts. When the area emerged as dry land, sluggish rivers meandered across great flats, carrying sediment to salt-water basins or fresh-water lakes, ultimately carving the flats into low hills and valleys very similar to those now found on the eastern prairies.

The climate became arid toward the close of the era, and those parts of the State that remained above water became deserts of shifting sands. These in time were stratified by constantly changing water levels into numerous grades of calcareous clays and sandstone. Rocks dating from this period are predominantly red, with occasional greenish and gray tints and even streaks of white. The upturned sedimentary led rocks along the eastern front of the Rocky Mountains, as seen in the Garden of the Gods at Colorado Springs and the Park of the Red Rocks west of Denver, are largely of late Paleozoic origin. The era closed with the crustal warping known as the Appalachian revolution, which raised the mountain chain of that name and spilled back the seas from Colorado.

The Paleozoic era was important in the evolution of plant and animal life. When the seas first advanced into Colorado, they brought sponges, marine worms, jellyfish, clams, snails, and other invertebrates. Before the first waters receded, some of these life form- had reached the height of their development and were beginning to decline. The second great advance of the Paleozoic seas occurred during the Devonian period, or Age of Fishes; there was a marked development of rnarine vertebrates, but fantastic trilobites, sea scorpions, and other invertebrates continued to flourish. Centipedes and spiders now crept along the rocks, and giant dragon flies—some with a wing spread of more than two feet—hovered over the marshes. Even before the Appalachian revolution amphibians had become the dominant form of animal life, and the progenitors of the reptile had appeared. Fossils of a primitive fish, believed to be one of the oldest vertebrates yet discovered, have been unearthed in late Paleozoic rock near Canon City.

While the skeletons of primitive fauna were being embedded as fossils in the rock museums at the bottom of the seas, the record of plant life was seriously damaged by erosion. The Paleozoic era probably opened with a luxurious growth of seaweeds throughout Colorado, but fossil evidence is lacking. During those periods when the land rose above the waters, it was a barren waste, without trees or vegetation. Millions of years later the State was covered with dense fern forests, in which grew primitive unisexual flowers; some trees, ferns, and club mosses attained heights of sixty to one hundred feet. As these and similar plants fell and decayed, they formed thick beds of peat, which later hardened into rich anthracite beds as in Pennsylvania; where conditions were favorable, a few such beds were created in Colorado.

Colorado entered the Mesozoic era, approximately one hundred and ten million years long, with a gigantic upheaval. Later, during the Jurassic period, the rise of the Colorado plateau was interrupted by a sudden brief return of the sea, followed by the creation of hundreds of large fresh-water basins in which were laid thin strata of varicolored rocks, chiefly limestones, sandstones, and marly shales. The Jurassic deposits east of the Continental Divide are known as the Morrison formation, those west of the Divide as the McElmo. The former underlies most of Colorado's eastern plains and appears here and there as outcrops along the frontal mountains from Wyoming to New Mexico.

Late in the Mesozoic era, during the Cretaceous period, an extension of the Gulf of Mexico invaded Colorado and joined a southward advancing arm of the Arctic Ocean. The entire State was again submerged, this time in a shallow mediterranean sea, a settling ground for gravel, sand, and mud containing millions of marine fossils. Gradually the gravel consolidated into conglomerate; the sand, into sandstone; and the mud, into shale—and all were cemented together by the weight of the surface layers above. Jurassic and Cretaceous rocks contain some of the most interesting fossils yet discovered in Colorado. Cretaceous rocks range in thickness from two thousand feet near the borders of the State to approximately ten thousand feet in the vicinity of Denver. The lower marine deposits contain numerous small oil reservoirs, while in the upper layers are valuable coal beds, laid down in fresh-water swamps and lagoons. The general emergence of the land during the era was accompanied by a marked improvement in climatic conditions, which in time transformed the Colorado desert into a garden.

Although great mountain-making movements, accompanied by igneous activity, recurred during later geological ages, the basic mountain structure of the region was formed about eighty million years ago, near the close of the Mesozoic era. A great warping and faulting movement gradually elevated the entire area above the surrounding plains, folding and tilting granite and sedimentary strata into jagged sky-scraping ranges. From gaping cracks in the upturned rocks poured molten lava, some of which congealed in crevices and subterranean reservoirs, but most of it burst from volcanic vents to tear immense holes in the mountain block. Avalanches of debris tumbled into the lowlands, and volcanic ash was so thickly scattered that it formed thick sedimentary layers over large areas. Erosion by wind, water, and glaciers through the ages has sculptured the mountain masses to their present contours, and has left such geological monuments as the Black Canyon of the Gunnison, the Royal Gorge of the Arkansas, Lodore Canyon of the Green, and Yampa Canyon.

The Mesozoic era was the age of reptiles; these creatures ruled land, sea, and air. Although turtles, crocodiles, lizards, and sea serpents reared powerful dynasties, the dinosaurs were easily supreme. These fantastic creatures ranged from one foot to eighty feet long, from a few inches to twenty feet high, and from a few pounds to scores of tons in weight. They were both herbivorous and carnivorous, and some species were heavily armored. Yet, before the close of the Mesozoic era, most of them had vanished, leaving only an insignificant posterity. Reptilian birds and more modest mammals appeared on the evolutionary horizon.

Skeletons of the grotesque monsters that once inhabited Colorado have been excavated from the Morrison formation near Denver; a Colorado diplodocus more than seventy-five feet long is on display, with many other paleontological treasures, at the Colorado Museum of Natural History, Denver. Near Canon City scientists have uncovered a dinosaur with feet three feet long and two and a half feet wide. Exposed rock strata along the hogbacks west of Denver contain thousands of ancient invertebrates of the Cretaceous period. Specimens of sea shells and dinosaur remains have been unearthed also on the Western Slope.

Mesozoic plant life emerged with great difficulty from the Colorado desert. Thickets of ferns, palms, cyceads, horsetails, and ginkgos first made their appearance; then conifer forests sprang up on the low subtropical hills. Yews, cypresses, cedars, and pines advanced rapidly toward modern types. Towards the close of the era appeared figs, magnolias, tulip trees, laurels, cinnamon trees, holly, oleanders, maples, birches, sycamores, oaks, beeches, and walnuts. Flowering plants flourished throughout the State. Today fossil palm leaves are found in many of Colorado's rock formations, particularly near Golden and Boulder. Valuable leaf imprints of the Cretaceous period come from the Green River formation, from rock beds near Chandler, and occasionally from deposits near Denver and at Florissant.

As the seas never returned to Colorado, the Cenozoic era—the most recent sixty million years of geological history—has left only a scanty record of itself in fresh water and saline lake deposits. The rocks of the Tertiary period, first of the chief subdivisions of the era, were laid down in shallow basins or on the flood plains of ill-defined and shifting rivers. Recent deposits in the State consist largely of windblows and sand dunes on the level plains, swamp muck in the higher mountain valleys, and alluvial gravel, sands, and loams along the streams.

Volcanic eruptions and crustal warpings continued until comparatively late in the Tertiary period, at which time the evolution of the Rocky Mountains and the Colorado plateau to their present form was completed. Colorado's metallic ore deposits apparently came from deep within the earth, forced up by volcanic activity, the chemical action of vapors, and rising water solutions, and were deposited in concentrated masses in the veins and faults of surface rocks. Evidence of this has been found in the mining camps of Cripple Creek, Alma, Breckenridge, Central City, and others where signs of former volcanic activity are manifest.

To some extent minerals are still being deposited, as is evidenced by the large number of hot mineral springs within the State. Although these thermal springs are undoubtedly much smaller than those of earlier geological periods, Big Pagosa Springs—the largest in the State—has an average flow of seven hundred gallons a minute, and those at Glen-wood Springs discharge some three thousand gallons a minute.

Minerals necessary for fertile soils have been supplied in abundance in Colorado. For the most part, its soils are sandy or gravelly loams, composed chiefly of fine grains of quartz, feldspar, and clay, with some-mica. Colorado prairie soils have an extremely wide range in both color and texture, and vary in appearance from light brown and almost chalky white to dark red, chocolate, and black. In texture they range from very fine sands to refractory adobes and clays.

The great ice sheet that scoured large sections of North America between twenty-five and sixty thousand years ago, did not touch Colorado. But exposed masses of glacial rock, isolated boulders, and terminal moraines indicate the presence of smaller alpine glaciers on many Colorado mountains. Remnants of these ice sheets still exist in Rocky Mountain National Park arid in the mountains west of Boulder. Beautiful cirques and U-shaped valleys at the eastern approach to Berthoud Pass are other reminders of this period.

While the turbulent end of the Mesozoic era was accompanied by conditions hazardous to plant and animal life, both flora and fauna evolved rapidly toward modern forms during the comparatively brief Cenozoic era. Birds cast off their reptilian characteristics and established a dynasty of their own. Mammals became the dominant type, Colorado fossils present a clear record of the evolution of the horse and the rhinoceros from primitive five-toed ancestors no larger than a dog. The evolution of the dog, cat, and bear families has been similarly traced in finds made within the State. The plains of northeastern Colorado have yielded remains of ancient turtles of gigantic size, as well as skeletons of the mammoth, giant pig, rhinoceros, and saber-toothed tiger. One of Colorado's paleontological prizes is the skull of a vintacolotherium, discovered in 1924 in the Eocene beds of Moffat County. This land animal approximated a small elephant in size, and had six horns, two huge fighting tusks, and a brain approximately as large as a sheep's.

Subtropical flora covered Colorado land surfaces during the early Tertiary period. Palm trees with broom-shaped leaves four feet long grew in the forests. Myrtles, sycamores, buckthorns, dogwoods, hawthorns, figs, sweet gums, cinnamons, and water lilies flourished; grasses took possession of all open spaces. Less favorable conditions prevailed after a new continental elevation, but with the retreat of the glaciers the climate again became temperate and modern forms of plant life proliferated.

During the prolonged construction and modification of the region now included within the State, nature played strange geological pranks. Among the resulting marvels is the Colorado National Monument in Mesa County near Grand Junction; huge caves and passages honeycomb the region, which is seamed with numerous canyons in which stand hundreds of monoliths like naked sentinels; names such as Steamboat Rock, Battle Rock, Double Balance Rock, Umbrella Rock, Devil's Kitchen, and Cold Shivers Point suggest the topography of the region. Erratic erosion has produced the fantastic volcanic formations of Wheeler National Monument in the south-central part of the State; here innumerable cones, massive plugs, and red pinnacles tower above majestic gorges. At Manitou Springs, near Colorado Springs, is the Garden of the Gods, a mass of upturned red rocks sculptured into weird formations; equally interesting is Red Rocks Park, west of Denver. The great shifting sand dunes in the San Luis Valley are the last remnants of a once vast prehistoric desert.