[Footnote 6: For convenience to navigation, the islands in the lower Mississippi, beginning at St. Louis, are numbered. Many of them, however, have local names by which they are frequently known.] Within a few years the town of Napoleon, which has already been mentioned as the site which beheld the cross erected by Marquette and the seizure of La Salle, was the scene of still another chapter in history. Almost two hundred years from the time when Joliet and Marquette beheld the historic ground, the river turned its current against the banks, and in a few hours the crumbling walls of an old stone building, half a mile or more from the river banks, were the surviving monument that marked the former location of the town. The Mississippi is indeed a grand study, and the people who have lived in its valley during past ages have seen the river doing just what it is doing to-day; and as race has succeeded race, each in turn has seen the landmarks of its predecessors swept away by its angry flood and buried beneath its sediment. Ever since the crests of the Appalachian and Rocky Mountains were thrust up above the sea, the river has been wearing them away, and bearing the scourings to the vast plain below. In the time of its building it has made the greatest and the richest valley on the face of the earth; next to that of the Amazon it is the largest, covering an area of one and one-quarter million square miles. The river and its tributaries drain twenty-eight States and Territories--an area equal to that of all Europe except Russia. This basin includes half the area of the United States, exclusive of Alaska. It is five times as large as Austria-Hungary, six times the size of France or Germany, nine times the area of Spain, and ten times that of the British Isles. Measured by its grain-producing capacity, this valley is capable of supporting a larger population than any other physical region on the face of the earth. Already it is the foremost region in the world in the production of grain, meat and cotton. The rich soil, sedentary on the prairie and alluvial in the bottomlands, is almost inexhaustible in its nutritious qualities. The soil cannot be "worn out" in the bottomlands, for nature restores its vitality by bringing fresh supplies from the highlands as fast or faster than the seed crop exhausts it. Sixty bushels of wheat or two bales of cotton may be harvested from an acre of bottom lands. So vast in proportions is the yearly crop of food stuffs that more than three hundred thousand freight cars and about two thousand vessels are required to move the crop from farm to market. One hundred and twenty-five thousand miles of railway, fifteen thousand miles of navigable water, exclusive of the Great Lakes, and several thousand miles of canals are insufficient to transport this enormous production; thousands of miles of railway are therefore yearly built in order to keep pace with the growth of population and the settlement of new lands.