Inhabitants flock in here daily, mostly from Pensilvania and other parts of America, who are over-stocked with people and some directly from Europe, they commonly seat themselves towards the West, and have got near the mountains. --Gabriel Johnston, Governor of North Carolina, to the Secretary of the Board of Trade, February 15, 1751. At the opening of the eighteenth century the tide of population had swept inland to the "fall line," the westward boundary of the established settlements. The actual frontier had been advanced by the more aggressive pioneers to within fifty miles of the Blue Ridge. So rapid was the settlement in North Carolina that in the interval 1717-32 the population quadrupled in numbers. A map of the colonial settlements in 1725 reveals a narrow strip of populated land along the Atlantic coast, of irregular indentation, with occasional isolated nuclei of settlements further in the interior. The civilization thus established continued to maintain a close and unbroken communication with England and the Continent. As long as the settlers, for economic reasons, clung to the coast, they reacted but slowly to the transforming influences of the frontier. Within a triangle of continental altitude with its apex in New England, bounded on the east by the Atlantic, and on the west by the Appalachian range, lay the settlements, divided into two zones--tidewater and piedmont. As no break occurred in the great mountain system south of the Hudson and Mohawk valleys, the difficulties of cutting a passage through the towering wall of living green long proved an effective obstacle to the crossing of the grim mountain barrier. In the beginning the settlements gradually extended westward from the coast in irregular outline, the indentations taking form around such natural centers of attraction as areas of fertile soil, frontier posts, mines, salt-springs, and stretches of upland favorable for grazing. After a time a second advance of settlement was begun in New Jersey, Pennsylvania, and Maryland, running in a southwesterly direction along the broad terraces to the east of the Appalachian Range, which in North Carolina lies as far as two hundred and fifty miles from the sea. The Blue Ridge in Virginia and a belt of pine barrens in North Carolina were hindrances to this advance, but did not entirely check it. This second streaming of the population thrust into the long, narrow wedge of the piedmont zone a class of people differing in spirit and in tendency from their more aristocratic and complacent neighbors to the east.