MAN THE IDEAL ANIMAL.

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continued to pass through important changes until late in geological time. Yet many of these animals, after a long career here, wholly disappeared while still continuing in Europe.

When the Glacial Period came on it is natural to suppose that the higher land animals retreated southward before it, and many of them survived it to perish before man could be benefited by them-as the horse, reindeer, and others. The animal kingdom continued, however, to be represented by huge and powerful animals, and to raise some of its classes in the scale of organization till man appeared. He was the Ideal Animal. Their progress had ever been (it is not proven how) from feeble to lively sensation; from few and confused parts and small measures of energy to many and highly elaborated sets of powers; from a few scattered fascicles of nerves to the extensive and well-protected system of the vertebrates; and the prone body and barrel form of the fish was soon excelled by a more and more erect head, while the long posterior body was shortened until only legs were left, while all the noble vital organs were raised in power and crowded into the front until the head was raised perpendicularly above them, and the fore legs were no longer instruments of locomotion but servants of the brain.

This uprightness, with the face and forehead on a perpendicular line with the front of the body, reached the limit of possible improvement in the frame, while the intelligence of man joined all the instincts and limited perceptions and passions of all the animal world in one mind, with undefined and fairly unlimited possibilities of power and growth, to which was added a class of faculties constituting his highest value-moral powers-the love of virtue and truth. As there can be no nobler frame in the animal world, so there can be no being essentially greater than man, in his highest and peculiar gifts, unless by an expansion of the same qualities. There was greater intelligence and power in the Principle

that planned and produced the world, but since man can comprehend the work he must be of the same nature as the Workman.

CHAPTER VII.

GENERAL VIEW OF THE FINISHED VALLEY.

We have seen how heat and the loss of heat provided the inconceivable force in the crust of the earth required for the immense changes of every geological age. The vastness of the power is very evident, as also is the restraint laid on it. It was, so to speak, tamed and made to work in harness. What it has done shows how easily it could have become a destroyer instead of a builder. Yet it worked slowly, cautiously, never getting ahead of its chemical, mechanical, and organic associates. Chemical attractions and repulsions made and unmade rocks, and stored up minerals at the points where the forethought that guided volcanic force and the power arising from contraction designated, winds and waves, sun and storm, torrent and gravity made rock in the proper places, and the Life Force worked with unflagging zeal in vegetable and animal to supply the most useful rocks and to store the richest treasures. Finally, cold came to do a most important surface work and then retired, leaving the slow falling and rising of the levels, the waters, dews, rains, and the sun to re-arrange the drift, vital energy to re-people it with animal and vegetable life, and present it finished to man when he should appear.

We have now to observe its general features as completed. From north to south the extreme of its length is about 2,000 miles; the extreme descent through its center in that distance being a little over 1,600 feet. The descent is nowhere very abrupt, although about three fourths of it are accomplished in the upper part of the Valley, from the head of the Mississippi to the mouth of the Missouri. The very gradual fall from

that point to the Gulf is one of the most important features of the Valley.

Its extremest width, from the heights of the eastern watershed to the crest of the Rocky Mountains, is not far from 1,600 miles. The western rim of the bowl is much the highest; about 2,000 feet in general along the east, though considerably higher in some places and lower in others; while the head waters of the Missouri are nearly 7,000 feet high; those of the Arkansas, 10,000; and of the Red River about 2,500. The descent on the west is very gradual, forming, for the most part, vast grassy plains, on which the steady change of level, though so great on the whole, is scarcely perceptible to the eye. On the east, the region inward from the mountains is much more broken, and, in part of West Virginia, Kentucky and Tennessee, a ridge of mountain is thrown westward, so that a northward slope is made to meet the general southward descent, in the bed of the Ohio. It is a ridge across the eastern center of the bowl which has prevented the extreme "washing" of the surface that has taken place west of the Missouri on the "Plains."

The whole of the united basins of the great central river and its branches, together with adjoining sections that naturally annex themselves to it by position and relations, cover an area of about 1,800.000 square miles-about the size of Europe without its colder and almost worthless northern regions and the poorer parts of Russia further south. The actual basins of the Mississippi and its tributaries cover an area of 1,256,000 square miles-it is often stated at 1,244,000, but that omits the delta. The adjoining and affiliated sections are the basin of the Great Lakes, which only a few feet of soil prevents from pouring its waters into the Mississippi, as it formerly actually did; the basin of the Red River of the North; and the Gulf coast, including the Valley of the Rio Grande, and, therefore, all of Texas, New Mexico, and Colorado, with large parts of the Territories further north. The length of the main river and

THE GREAT RIVER AND ITS BRANCHES.

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its subordinate streams, the height of their head-waters above the level of the sea, and the area of their basins, with some other facts, are given in the following table from Humphrey's and Abbot's "Report to the Government on the Physics and Hydraulics of the Mississippi River."

This grand network of rivers supplies an internal navigation by steamboats of near 9,000 miles. The main stream is navigable from its mouth to St. Paul by large steamers 1,944 miles

-and beyond St. Anthony's Falls 80 miles further, with 350 miles, on its branches in Minnesota and 220 miles on the Illinois River. The Ohio is navigable to Pittsburgh, 975 miles and that distance is about doubled by including the capacity of its branches. The Missouri is navigable almost 2,000 miles, and in high water 600 more. The Arkansas and the Red Rivers are navigable several hundred miles and the distance is doubled in high water. Several other streams add many hundreds of miles to navigation.

The regions of the Valley so reached are the fairest and richest for farming and mercantile purposes. The eastern and central parts of the Valley are extremely well watered, and the shore-line of the Great Lakes, the Gulf shore, and navigable streams emptying into it, altogether furnish for the