Over most of the Province of the Lake and Prairie Plains the Laurentide glacier spread its drift, rich in limestone and other rock powder, which farmers in less favored sections must purchase to replenish the soil. The alluvial deposit from primeval lakes contributed to fatten the soil of other parts of the prairies. Taken as a whole, the Prairie Plains surpass in fertility any other region of America or Europe, unless we except some territory about the Black Sea. It is a land marked out as the granary of the nation; but it is more than a granary. On the rocky shores of Lake Superior were concealed copper mines rivaled only by those of Montana, and iron fields which now[129:1] furnish the ore for the production of eighty per cent of the pig iron of the United States. The Great Lakes afford a highway between these iron fields and the coal areas of the Ohio Valley. The gas and oil deposits of the Ohio Valley, the coal of Illinois, Iowa, Michigan, and eastern Kansas, the lead and zinc of the Ozark region and of the upper Mississippi Valley, and the gold of the black Hills,--all contribute underground wealth to the Middle West. The primeval American forest once spread its shade over vast portions of the same province. Ohio, Indiana, southern Michigan, and central Wisconsin were almost covered with a growth of noble deciduous trees. In southern Illinois, along the broad bottom lands of the Mississippi and the Illinois, and in southern and southwestern Missouri, similar forests prevailed. To the north, in Michigan, Wisconsin, and Minnesota, appeared the somber white pine wilderness, interlaced with hard woods, which swept in ample zone along the Great Lakes, till the deciduous forests triumphed again, and, in their turn, faded into the treeless expanse of the prairies. In the remaining portions were openings in the midst of the forested area, and then the grassy ocean of prairie that rolled to west and northwest, until it passed beyond the line of sufficient rainfall for agriculture without irrigation, into the semi-arid stretches of the Great Plains. In the middle of the eighteenth century, the forested region of this province was occupied by the wigwams of many different tribes of the Algonquin tongue, sparsely scattered in villages along the water courses, warring and trading through the vast wilderness. The western edge of the prairie and the Great Plains were held by the Sioux, chasing herds of bison across these far-stretching expanses. These horsemen of the plains and the canoemen of the Great Lakes and the Ohio were factors with which civilization had to reckon, for they constituted important portions of perhaps the fiercest native race with which the white man has ever battled for new lands.