Free Centennial by James A. Michener Page A

years. When the area rose, it rose too. When minor faults appeared, it adjusted to them. And when the area subsided, the golden pipe fell with it, still ensconced under the north bank of the little stream. In time roots of the golden aspen formed a network above it.
    When the first great glacier filled the valley it stripped away some fifty feet of cover protecting the near end of the pipe, but no other change occurred. Each succeeding glacier cut away a little more of the protection until the last one came. Sometime around the year 1,000 B.C. this glacier actually cut away six feet of the pipe and scattered the gold that it had contained along the bottom of the stream for a distance of some two hundred yards.
    This same glacier, of course, deposited gravel over the exposed end of the pipe, so that it could not easily be detected, and hid the nuggets of gold that lay at the bottom of the stream. Then trees returned and the gold was buried again, but each autumn when leaves of the aspen turned, this was a valley that was doubly golden.
    The third place was conspicuous from all directions, and spectacular, but what was significant about it was hidden, and we shall not know of it till later.
    Some sixty-five million years ago—shortly after the emergence of the New Rockies—the river began hauling down an extraordinary amount of rock, gravel and sand, which it deposited in a thick overlay on the flat plains to the east. We have observed this phenomenon before, so there is no need to recapitulate, except to state that at the location we are talking about, a spot to the north of Centennial and slightly to the east, the deposit eventually, was more than two hundred feet thick.
    When this process was completed, thirty-eight million years ago, the plains to the east were so built up that they blended harmoniously into the lower reaches of the New Rockies, creating a lovely sweep that extended in unbroken beauty several hundred miles into Nebraska and Kansas. This symmetry did not endure, for the New Rockies experienced a massive uplifting, which raised them above the gentle sweep. As a result, the river now dropped more steeply from the mountains, carrying with it many cutting rocks. It surged eastward and for twelve million years dominated the foothills, cutting them away, scraping down hillocks, and depositing on the plains new layers of soil characterized by a rocky, infertile content.
    The great inland sea which had once dominated this area had long vanished, so that the building of this new rock had to be accomplished in open air. The river would bring down deposits, which would spread out in fans. Sun and wind would act upon them, and new deposits would form over them. Gradually, disparate components would begin to solidify, and as heavier forms accumulated on top, those on the bottom would coalesce to form conglomerates.
    Each year the plains grew a little higher, a little more stable in their footing. Finishing touches were applied about eleven million years ago, when a sandstone rock was laid down, sealing the entire region. This final rock had a peculiar characteristic: at the spot we are talking about, north of Centennial, some variation occurred in the cement which bound the granular elements together. Different from the cement operating in nearby regions, it had been formed perhaps from volcanic ash which had drifted in; at any rate, it created an impermeable caprock which would protect the softer sandstone that rested beneath.
    At last the vast job of building was ended. From the period when the New Rockies underwent their secondary uplift, some three hundred and twenty feet of solid rock and soil had been laid down, all protected by the caprock, and had there been an observer at the time, he could have been excused had he concluded that what he saw then, eight million years ago, would be the final structure of the plains.
    But it was still the river which determined what the surface of the land would be, and starting