tion and condition of the sun, and other distant bodies, were very positively made out. So much clear and precise knowledge has been gained in the last fifty years, that it would be presumptuous to undertake to mark the future boundaries between the known and the unknown, or perhaps to say that any subject awakening the interest and curiosity of men will not be sufficiently investigated and cleared up to fully satisfy that curiosity.

The outlines of what science has revealed of the past of one of the most important regions of the earth, are given in the First Part of this work. So far as we can discover all the labors of nature are directed toward an ultimate end in connection with man. The Mississippi Valley seems to have been formed with peculiar care on a broad and simple plan and to have been supplied with a variety, abundance and excellence of useful materials seen nowhere else in the world.

It can not but be of interest to note how and when the original plan of the great Valley was drawn, and how the operations that stored it with so many treasures were conducted. Science is able to give a very clear and connected history of this long process, and also to furnish a most interesting tale of an ancient and mysterious people of whom written history knows almost nothing, or at least nothing definite. The facts and the manner in which they have been studied and their meaning learned are contained in a multitude of books. The details must be sought in those. It is only the general conclusions that are here given.

CHAPTER I.

HOW NATURE FORMED THE GREAT VALLEY.

The Book accepted as a Divine Record and Revelation by the Jews, and afterwards by Christians, opens with a brief and partial outline of the origin of the earth and its progressive fitting up for the use and residence of man. Nature itself must be a revelation, if its narrative can be read, and the two. records should be in harmony. The Bible account contains a very brief summary, and leaves wide gaps in the outlinetouching but few points. Naturally it would not be fully comprehended until the outline was completed and explained by a multitude of details. This was the task of science, and the more definite and unmistakable its conclusions become, the more decisive appears the agreement between the two records.

The Bible commences with "the beginning," when the elements, which came ultimately to their present state, were formless, confused, and utterly "dark;" confines its statements concerning the early periods chiefly to the origin and development of light, to the gradual introduction of plants and animals, and, finally, of man. Science commences with an examination of the finished work-with the earth as it is now-and follows the process back, step by step, to the time when no life existed, and when it first became possible for the earth to be illuminated as it is now. It confirms, explains and fills up the Bible outline so far as it can reach positive conclusions. It discovers evidences of a heated state in which rocks and metals were melted, or existed only in the form of gas or vapor, through which the light of the sun could not penetrate. The earth gradually cooled, a crust formed over the

molten mass, the vapors condensed and fell to the surface as water, and minerals diffused in it, much of which last at length became solid, leaving the atmosphere as a transparent gas through which the bright sunshine fell on the solid surface, or the waters, and in which a portion of the water, whenever turned to vapor by heat, floated as clouds, became condensed and fell in the form of rain.

Astronomy and chemistry aid us to go back a step beyond even this state of fusion, and confirm the Bible statement that the earth was "without form and void, and darkness was upon the face of the deep;" when progress commenced by "movement," or motion, communicated by some power to the dif fused elements of matter. Men of science see reason to conclude that the material of the solid mass of the earth, as well as its liquid and gaseous parts, existed then as thin vapor, the particles of matter being widely separated, thinner and lighter than air, and cold and lifeless, so to speak, because they were not near enough to act and react on each other. To introduce this action they must be condensed-brought into contact. When this was done great activity commenced, producing an immense development of heat accompanied by "light." In this state of lively action particles of the same kind sought each other, came together, or condensed, ultimately hardened, and a direct process of fitting up the surface for man commenced.

So far, therefore, as the two records touch on the same points they mutually confirm each other; the order in which organized living things were introduced in later times being substantially the same in each. The Bible narrative is incomplete, yet remarkably exact as far as it goes. The word "day," in the sacred narrative, which has perplexed so many and formerly caused the conclusions of science to be looked upon with suspicion, is used in several senses in that narrative itself, and is now commonly regarded as presenting no obstacle to the harmony of the two records.

THE ORIGIN OF THE EARTH.

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It is, therefore, believed that the whole planetary system was, at first, one vast mass of vapor, which, gradually confracting as it revolved, threw off successive rings which collected in separate masses and condensed independently--the process of condensation being more rapid in proportion as the masses were smaller. The vast central mass-the sun-still remains in the condition in which the earth once was—a ball of glowing fire-the other planets being in the various stages of progress according to their size and rate of motion. This is a theory long since entertained, and, though doubted by some or considered not fully proved, it seems to be confirmed in various ways by the researches of science.

Heat is latent, or unperceived, in vapor. It is developed by motion-it is said to be a mode of motion-and it appears to be connected with all the vast activities that have made the earth what it is. The most violent motion produced, or was accompanied by, the greatest displays of heat. When the boiling matter of the earth began to part with its heat, it contracted so as to occupy less space. It boiled down, so to speak, the lighter and the heavier elements separated, the gases and the vapors that were to form the atmosphere and the waters or to be gradually returned as solids at a later period-became the envelope of the heavier pasty mass at the center.

Thus the central mass thickened, shrunk, as it parted with its heat, until a scum or crust formed at the surface. At first this crust was too hot to allow the vapor to condense into water but it continued to thicken and cool until a universal sea covered it. The waters were at first hot and saturated with corrosive minerals, which eat into and wore down the surface of the hardened rock, so that this was finally buried under a thick layer of these minute fragments. These fragments gradually consolidated and formed the first or azoic rock-which contained no sign of life-that was raised out of the waters. was this which, pulverized by the atmosphere, the rain or the

It

waves, furnished material for the layers of rock formed in later ages. Each age left in the rocks formed in it some traces of its plant and animal life.

It would seem that, by the operation of some law as yet unknown, the surfaces where the continents were to be, hardened first, and the lines that were to separate the future continent and ocean were drawn at the very beginning. The study of coast lines, of mountain chains and their various ages, with the forces that must have raised them, proves a steady operation of influences in the same direction from the beginning, and renders it quite improbable that the continents and ocean beds have really ever changed places to any great extent. The continents and their immense ranges of mountains were steadily lifted (or prepared to be raised) while the ocean beds were as steadily depressed until late in geological times. Apparently this result was largely due to the stiffening of the crust over the continental areas first. The melted rock contracted eight to twelve per cent in volume as it cooled and became immovable; that which cooled last would lie lower and be thinner and more yielding at any given period; and as the mass beneath cooled it shrunk, and the crust must settle to find support. As it settled to the smaller dimensions of this shrinking ball the crust must wrinkle and fold and produce the mountain systems and continental plateaus of the earth. As the sea bottoms lay lower and yielded to the descending movement most readily (being somewhat thinner because later formed) they must find room by pressing obliquely up against the borders of the continents, thereby tending to raise them as a whole, as well as to fold them, in places, into mountain chains.

Accordingly, mountains are usually found not far from the border of the continents, are steepest on the sides which front the sea, from which the strongest lifting pressure came, and it is found that the higher mountains of a continent border the largest ocean. In America, the Rocky Mountains border