In the north the great rivers lay across the tedious paths that ran with the lines of latitude. And so it was partly for physiographic reasons that the first far-stretching expansions of the New England settlements were not toward this great western wilderness but northward along the narrower valleys. It was not until the migration had filled the meagre limits and capacities of these smaller valleys and had carried school-houses and churches and town halls well up granite hillsides, that the western exodus came, to leave those hillside homes and institutional shelters as shells found far from a receding sea, empty or habited by a new species of immigrant. [Footnote: In one of those far northern valleys which I know best there was a school, before the exodus, of some seventy pupils, gathered from the farmers' families of the neighborhood. Now there are not a half-dozen pupils, and they are carried to a neighboring district.] Farms were abandoned for the fertile fields of the far west, from which wheat can be imported for less than the cost of raising it on the sterile hills and in the short-summered valleys. New England had once claimed a fraction of the great west, as, indeed, had most of the other seaboard colonies. But these claims were surrendered to the general government, as we shall see later, "for the common good," and so her migrants had none other than that instinct which follows lines of latitude to keep them practically within the zone of her relinquished claims. Over into New York, New Jersey, and Pennsylvania her children overflowed till a map of these States in 1820, colored to show the origin and character of their various communities, made practically all of western New York, a part of New Jersey and the northern third of Pennsylvania, an expanded New England. Meanwhile the hardiest joined the transmontane migration, and in the decade after the opening of the Erie Canal (1830-40) the whole northern edge of the valley takes color of New England conquest. So the first peopling was a mingling of the children of the first strugglers with a raw savage continent; men already schooled in adversity, already acquainted with some of the frontier problems--civilization's most highly individualized, least socialized material, the wheat of the new world's first winnowing. What is particularly to be observed is that men of the north and the south, as far apart as Carolina and Massachusetts, came together beyond the mountains in the united building of commonwealths; for over those mountains the rivers all ran toward the Mississippi, which tied the interests of all together.