The exploitation of the beasts took hunter and trader to the west, the exploitation of the grasses took the rancher west, and the exploitation of the virgin soil of the river valleys and prairies attracted the farmer. Good soils have been the most continuous attraction to the farmer's frontier. The land hunger of the Virginians drew them down the rivers into Carolina, in early colonial days; the search for soils took the Massachusetts men to Pennsylvania and to New York. As the eastern lands were taken up migration flowed across them to the west. Daniel Boone, the great backwoodsman, who combined the occupations of hunter, trader, cattle-raiser, farmer, and surveyor--learning, probably from the traders, of the fertility of the lands of the upper Yadkin, where the traders were wont to rest as they took their way to the Indians, left his Pennsylvania home with his father, and passed down the Great Valley road to that stream. Learning from a trader of the game and rich pastures of Kentucky, he pioneered the way for the farmers to that region. Thence he passed to the frontier of Missouri, where his settlement was long a landmark on the frontier. Here again he helped to open the way for civilization, finding salt licks, and trails, and land. His son was among the earliest trappers in the passes of the Rocky Mountains, and his party are said to have been the first to camp on the present site of Denver. His grandson, Col. A. J. Boone, of Colorado, was a power among the Indians of the Rocky Mountains, and was appointed an agent by the government. Kit Carson's mother was a Boone.[19:1] Thus this family epitomizes the backwoodsman's advance across the continent. The farmer's advance came in a distinct series of waves. In Peck's New Guide to the West, published in Boston in 1837, occurs this suggestive passage: