Page:Popular Science Monthly Volume 31.djvu/490

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474
THE POPULAR SCIENCE MONTHLY.

Significant of this was the feeling of the American people during the fearful droughts a few years since in the States west of the Missouri. No days were appointed for fasting and prayer to bring rain—there was no attribution of the calamity to the wrath of God or the malice of Satan; but much was said regarding the folly of our people in allowing the upper regions of their vast rivers to be denuded of forests, thus subjecting the States below to alternations of drought and deluge. Partly as a result of this, a beginning has been made of teaching forest-culture in many schools, tree-planting societies have been formed, and "Arbor-day" is recognized in several of the States. A true and noble theology can hardly fail to recognize in the love of Nature and care for our fellow-men thus promoted, something far better, both from a religious and a moral point of view, than any efforts to propitiate the Divine anger by flattery, or to avert Satanic malice by fetichism.

 

THE FALLS OF THE MISSISSIPPI.
By JOHN ARNOLD KEYES.

THE Mississippi River and its tributaries, forming as they do one of the most important river systems on the globe, and draining one of the most richly-furnished continental areas, present, moreover, many interesting geological studies, and open up fields of curious inquiry to the investigator. The old discussions as to the possibility or impossibility of things has, for the most part, passed out of existence in this department of science. No one now denies the general principles of geology as at present taught; therefore new regions of investigation are to be approached on the firm foundation of the old, and difficult matters settled in conformity with established principles. That there is no new thing under the sun is a saying well worn, but in one sense correct, yet the same thing recognized as a fact in one situation may under other circumstances seem a fallacy. The Falls of Niagara are familiar to all, and came to exist through causes natural and easy of explanation, inasmuch as the whole secret lies in the character of the formations over which the river flows, viz., a crust made up of from sixty to one hundred feet of comparatively hard limestone lying in a nearly horizontal position, beneath which is a deep deposit of shales and sandstones. Whenever the river in wearing its channel back reached the point where this arrangement of rocks began, the hard limestone would naturally resist the erosive action of the waters, while the underlying shales and sandstones, offering less resistance, would be rapidly cut away, until a vertical fall such as is now seen would be the result, with a constant recession going on, leaving below the broad canon, walled on either hand by bluffs, the crests of which are preserved by the limestone crowning them.