But already the Mississippi Valley was beginning to stratify, both socially and geographically. As the railroads pushed across the mountains, the tide of New England and New York colonists and German immigrants sought the basin of the Great Lakes and the Upper Mississippi. A distinct zone, industrially and socially connected with New England, was forming. The railroad reinforced the Erie Canal and, as De Bow put it, turned back the tide of the Father of Waters so that its outlet was in New York instead of New Orleans for a large part of the Valley. Below the Northern zone was the border zone of the Upland South, the region of compromise, including both banks of the Ohio and the Missouri and reaching down to the hills on the north of the Gulf Plains. The Cotton Kingdom based on slavery found its center in the fertile soils along the Lower Mississippi and the black prairies of Georgia and Alabama, and was settled largely by planters from the old cotton lands of the Atlantic States. The Mississippi Valley had rejuvenated slavery, had given it an aggressive tone characteristic of Western life. Thus the Valley found itself in the midst of the slavery struggle at the very time when its own society had lost homogeneity. Let us allow two leaders, one of the South and one of the North, to describe the situation; and, first, let the South speak. Said Hammond, of South Carolina,[198:1] in a speech in the Senate on March 4, 1858: I think it not improper that I should attempt to bring the North and South face to face, and see what resources each of us might have in the contingency of separate organizations. Through the heart of our country runs the great Mississippi, the father of waters, into whose bosom are poured thirty-six thousand miles of tributary streams; and beyond we have the desert prairie wastes to protect us in our rear. Can you hem in such a territory as that? You talk of putting up a wall of fire around eight hundred and fifty thousand miles so situated! How absurd.