Page:Popular Science Monthly Volume 23.djvu/490

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THE POPULAR SCIENCE MONTHLY.

valley, where the fire is nearest the surface, the entire superstratum breaks up and crumbles to ruin. When, after a summer storm, the flood comes down the valley, shoots into the crevices, and runs along the fissures, something like an explosion takes place. On every side volumes of steam ascend, but the fire is not extinguished. The loosened earth is much of it swept away, and a deep gulch forms between the ridges, and so the air comes freely to the fire, which might otherwise be smothered in its own ruin. Meanwhile the hearts of the hills themselves are baked like tiles in a close kiln, and while the fire would seem to hasten erosion, as in some places it certainly does, yet the metamorphism accomplished tends in the opposite direction, and is efficient in proportion to the completeness of the change.

And so the work goes on; one bed of lignite after another takes fire, one butte after another becomes the cover of a kiln, a furnace, and the whole country is transformed. I say the work goes on; better, has gone on, for it is nearly done. Glowing or smoldering through ages past, now hidden in darkness, now breaking forth to light, these secret fires have been burning, burning like a hidden fever, until the fair face of Nature has become an arid desert.

Thus the Bad Lands, as we know them, are the results of the action of two opposing elements, the water and the fire. Of these two the first had doubtless acted alone long before the second entered at all into the problem of disintegration. These level tops bespeak a former continuous level plain. More than this: into the highest of the buttes we may trace the same strata which make up the lower hills. The level must at one time have been higher still than we had first supposed. The changes of the past are enormous as compared with anything shown by the present, or even possible in the future of these strata. Owing to the peculiar nature of the strata, their uniformity and lack of solidity, the erosion has produced effects unique, and to these the fire has brought permanence and stability. Far as the coal beds extend erosion has been or is liable to be arrested, and the country doomed to infertility. But the coal is not universally present. Many places are free from it entirely, and here erosion may continue unchecked its peaceful processes until all is beaten down to the common plain. In other places the coal takes fire in but isolated hills, and these become permanent while all else is reduced to prairie. And now we remember that away to the east the plains sometimes show a solitary hill, whose sides, reddening beneath the sparse grass, and whose summit, glowing in the sunshine, betray its origin.