Part 7

Let us, for illustration, consider for a moment the making of America. The earth, composed of countless aggregations of matter drawn together from the skies, whirled into a globe, settled into a solid mass surrounded by an atmosphere carrying water like a sponge, has reached the stage of development when land and sea have divided the surface between them, and successions of heat and frost, snow, ice, rain, and flood, are busy with their ceaseless carving of the land. Already mountains are wearing down and sea bottoms are building up with their refuse. Sediments carried by the rivers are depositing in strata, which some day will harden into rock.

We are looking now at the close of the era which geologists call Archean, because it is ancient beyond knowledge. A few of its rocks are known, but not well enough for many definite conclusions. All the earth's vast mysterious past is lumped under this title.

The definite history of the earth begins with the close of the dim Archean era. It is the lapse from then till now, a few hundred million years at most out of all infinity, which ever can greatly concern man, for during this time were laid the only rocks whose reading was assisted by the presence of fossils. During this time the continents attained their final shape, the mountains rose, and valleys, plains, and rivers formed and re-formed many times before assuming the passing forms which they now show. During this time also life evolved from its inferred beginnings in the late Archean to the complicated, finely developed, and in man's case highly mentalized and spiritualized organization of To-day.

Surely the geologist's field of labor is replete with interest, inspiration, even romance. But because it has become so saturated with technicality as to become almost a popular bugaboo, let us attempt no special study, but rather cull from its voluminous records those simple facts and perspectives which will reveal to us this greatest of all story books, our old earth, as the volume of enchantment that it really is.

With the passing of the Archean, the earth had not yet settled into the perfectly balanced sphere which Nature destined it to be. In some places the rock was more compactly squeezed than in others, and these denser masses eventually were forced violently into neighbor masses which were not so tightly squeezed. These movements far below the surface shifted the surface balance and became one of many complicated and little known causes impelling the crust here to slowly rise and there to slowly fall. Thus in places sea bottoms lifted above the surface and became land, while lands elsewhere settled and became seas. There are areas which have alternated many times between land and sea; this is why we find limestones which were formed in the sea overlying shales which were formed in fresh water, which in turn overlie sandstones which once were beaches--all these now in plateaus thousands of feet above the ocean's level.

Sometimes these mysterious internal forces lifted the surface in long waves. Thus mountain chains and mountain systems were created. Often their summits, worn down by frosts and rains, disclose the core of rock which, ages before, then hot and fluid, had underlain the crust and bent it upward into mountain form. Now, cold and hard, these masses are disclosed as the granite of to-day's landscape, or as other igneous rocks of earth's interior which now cover broad surface areas, mingled with the stratified or water-made rocks which the surface only produces. But this has not always been the fate of the under-surface molten rocks, for sometimes they have burst by volcanic vents clear through the crust of earth, where, turned instantly to pumice and lava by release from pressure, they build great surface cones, cover broad plains and fill basins and valleys.

Thus were created the three great divisions of the rocks which form the three great divisions of scenery, the sediments, the granites, and the lavas.

During these changes in the levels of enormous surface areas, the frosts and water have been industriously working down the elevations of the land. Nature forever seeks a level. The snows of winter, melting at midday, sink into the rocks' minutest cracks. Expanded by the frosts, the imprisoned water pries open and chips the surface. The rains of spring and summer wash the chippings and other débris into rivulets, which carry them into mountain torrents, which rush them into rivers, which sweep them into oceans, which deposit them for the upbuilding of the bottoms. Always the level! Thousands of square miles of California were built up from ocean's bottom with sediments chiselled from the mountains of Wyoming, Colorado, and Utah, and swept seaward through the Grand Canyon.

These mills grind without rest or pause. The atmosphere gathers the moisture from the sea, the winds roll it in clouds to the land, the mountains catch and chill the clouds, and the resulting rains hurry back to the sea in rivers bearing heavy freights of soil. Spring, summer, autumn, winter, day and night, the mills of Nature labor unceasingly to produce her level. If ever this earth is really finished to Nature's liking, it will be as round and polished as a billiard ball.

MIDDLE FORK OF THE BELLY RIVER, GLACIER NATIONAL PARK

Very ancient shales and limestone fantastically carved by glaciers. The illustration shows Glenns Lake, Pyramid Peak, Chaney Glacier, and Mount Kipp]

Years mean nothing in the computation of the prehistoric past. Who can conceive a thousand centuries, to say nothing of a million years? Yet either is inconsiderable against the total lapse of time even from the Archean's close till now.

And so geologists have devised an easier method of count, measured not by units of time, but by what each phase of progress has accomplished. This measure is set forth in the accompanying table, together with a conjecture concerning the lapse of time in terms of years.

The most illuminating accomplishment of the table, however, is its bird's-eye view of the procession of the evolution of life from the first inference of its existence to its climax of to-day; and, concurrent with this progress, its suggestion of the growth and development of scenic America. It is, in effect, the table of contents of a volume whose thrilling text and stupendous illustration are engraved immortally in the rocks; a volume whose ultimate secrets the scholarship of all time perhaps will never fully decipher, but whose dramatic outlines and many of whose most thrilling incidents are open to all at the expense of a little study at home and a little thoughtful seeing in the places where the facts are pictured in lines so big and graphic that none may miss their meanings.

Man's colossal egotism is rudely shaken before the Procession of the Ages. Aghast, he discovers that the billions of years which have wrought this earth from star dust were not merely God's laborious preparation of a habitation fit for so admirable an occupant; that man, on the contrary, is nothing more or less than the present master tenant of earth, the highest type of hundreds of millions of years of succeeding tenants only because he is the latest in evolution.

PROGRESS OF CREATION

Chart of the Divisions of Geologic Time, and an Estimate in Years based on the assumption that a hundred million years have elapsed since the close of the Archean Period, together with a condensed table of the Evolution of Life from its Inferred Beginnings in the Archean to the Present Time. Read from the bottom up. Read the footnote upon the opposite page concerning the Estimate of Time.

---------+---------------+--------------+-----------------------+---------- ERA | PERIOD | EPOCH | LIFE DEVELOPMENT | ESTIMATED | | | | TIME ---------+---------------+--------------+-----------------------+---------- | | Recent | THE AGE OF MAN | CENOZOIC | Quaternary | Pleistocene |Animals and plants of | 6 | | (Ice Age) |the modern type. First | millions | | |record of man occurs in| of | | |the early Pleistocene. | years. Era of +---------------+--------------+-----------------------+ Recent | | Pliocene | THE AGE OF MAMMALS | Life | Tertiary | Miocene |Rise and development of| | | Oligocene |the highest orders of | | | Eocene |plants and animals. | ---------+---------------+--------------+-----------------------+---------- | Cretaceous | | THE AGE OF REPTILES | MESOZOIC | Jurassic | |Shellfish with complex | | Triassic | |shells. Enormous land | | | |reptiles. Flying | 16 | | |reptiles and the | millions | | |evolution therefrom of | of | | |birds. First palms. | years. | | |First hardwood trees. | | | | First mammals. | Era of +---------------+--------------+-----------------------+ Intermediate | | THE AGE OF AMPHIBIANS.| Life | | | THE COAL AGE | |Carboniferous| Permian |Sharks and sea animals | | | |with nautilus-like | | |Pennsylvanian |shells. Evolution of | | | |land plants in many | | |Mississippian |complex forms. First | | | |appearance of land | | | |vertebrates. First | | | |flowering plants. | | | |First cone-bearing | | | |trees. Club mosses and | | | |ferns highly developed.| ---------+---------------+--------------+-----------------------+---------- | | | THE AGE OF FISHES | | Devonian | |Evolution of many | | | |forms. Fish of great | | | |size. First appearance | 45 | | |of amphibians and land | millions | | |plants. | of +---------------+--------------+-----------------------+ years. PALEOZOIC| | |Shellfish develop | Era of | Silurian | |fully. Appearance and | Old Life | | |culmination of crinoids| | | |or sea-lilies, and | | | |large scorpion-like | | | |crustaceans. First | | | |appearance of | | | |reef-building corals. | | | |Development of fishes. | +---------------+--------------+-----------------------+ | | |Sea animals develop | | Ordovician | |shells, especially | | | |cephalopods and | | | |mollusk-like | | | |brachiopods. Trilobites| | | |at their height. First | | | |appearance of insects. | | | |First appearance of | | | |fishes. | +---------------+--------------+-----------------------+ | | |More highly developed | | Cambrian | |forms of water life. | | | |Trilobites and | | | |brachiopods most | | | |abundant. Algæ. | ---------+---------------+--------------+-----------------------+---------- | Algonkian | |The first life which | | | |left a distinct record.| 33 | | |Very primitive forms | millions PROTEROZOIC | |of water life, | of | | |crustaceans, | years. | | |brachiopods and algæ. | ---------+---------------+--------------+-----------------------+---------- | Archean | |No fossils found, but | | | |life inferred from the | | | |existence of iron ores | ARCHEOZOIC | |and limestones, which | | | |are generally formed in| | | |the presence of | | | |organisms. | ---------+---------------+--------------+-----------------------+----------

Who can safely declare that the day will not come when a new Yellowstone, hurled from reopened volcanoes, shall found itself upon the buried ruin of the present Yellowstone; when the present Sierra shall have disappeared into the Pacific and the deserts of the Great Basin become the gardens of the hemisphere; when a new Rocky Mountain system shall have grown upon the eroded and dissipated granites of the present; when shallow seas shall join anew Hudson Bay with the Gulf of Mexico; when a new and lofty Appalachian Range shall replace the rounded summits of to-day; when a race of beings as superior to man, intellectually and spiritually, as man is superior to the ape, shall endeavor to reconstruct a picture of man from the occasional remnants which floods may wash into view?

NOTE EXPLANATORY OF THE ESTIMATE OF GEOLOGIC TIME IN THE TABLE ON THE OPPOSITE PAGE

The general assumption of modern geologists is that a hundred million years have elapsed since the close of the Archean period; at least this is a round number, convenient for thinking and discussion. The recent tendency has been greatly to increase conceptions of geologic time over the highly conservative estimates of a few years ago, and a strong disposition is shown to regard the Algonkian period as one of very great length, extremists even suggesting that it may have equalled all time since. For the purposes of this popular book, then, let us conceive that the earth has existed for a hundred million years since Archean times, and that one-third of this was Algonkian; and let us apportion the two-thirds remaining among succeeding eras in the average of the proportions adopted by Professor Joseph Barrell of Yale University, whose recent speculations upon geologic time have attracted wide attention.

Fantastic, you may say. It is fantastic. So far as I know there exists not one fact upon which definite predictions such as these may be based. But also there exists not one fact which warrants specific denial of predictions such as these. And if any inference whatever may be made from earth's history it is the inevitable inference that the period in which man lives is merely one step in an evolution of matter, mind and spirit which looks forward to changes as mighty or mightier than those I have suggested.

With so inspiring an outline, the study to which I invite you can be nothing but pleasurable. Space does not permit the development of the theme in the pages which follow, but the book will have failed if it does not, incidental to its main purposes, entangle the reader in the charm of America's adventurous past.

THE NATIONAL PARKS OF THE UNITED STATES

The National Parks of the United States are areas of supreme scenic splendor or other unique quality which Congress has set apart for the pleasure and benefit of the people. At this writing they number eighteen, sixteen of which lie within the boundaries of the United States and are reached by rail and road. Those of greater importance have excellent roads, good trails, and hotels or hotel camps, or both, for the accommodation of visitors; also public camp grounds where visitors may pitch their own tents. Outside the United States there are two national parks, one enclosing three celebrated volcanic craters, the other conserving the loftiest mountain on the continent.

The starting point for any consideration of our national parks necessarily is the recently realized fact of their supremacy in world scenery. It was the sensational force of this realization which intensely attracted public attention at the outset of the new movement; many thousands hastened to see these wonders, and their reports spread the tidings throughout the land and gave the movement its increasing impetus.

The simple facts are these:

The Swiss Alps, except for several unmatchable individual features, are excelled in beauty, sublimity and variety by several of our own national parks, and these same parks possess other distinguished individual features unrepresented in kind or splendor in the Alps.